Summary reports from this meeting include:

• HAART use among women in UK receiving treatment prior to conception
• Duration of ruptured membranes and vertical transmission in the UK
• Significant rates of unplanned pregnancies among young women born with HIV
• Route of HCV transmission in HIV-positive gay men is unlikely to be from semen
• Increase in LGV cases in gay men report in the UK
• 75% HIV-positive children have insufficient levels of Vitamin D
• High rates of osteopenia and osteoporosis: importance of DEXA monitoring
• Summaries of other studies

Abstracts from the conference are published as a supplement to the May 2010 edition of HIV Medicine; Volume 11, Supplement 1.

Until these are posted on the aegis.org conference abstract database, a PDF files abstract is:

http://www.aegis.org/conferences/BHIVA/2010/16BHIVA-2010.pdf

HIV positive women in the UK are increasingly receiving HAART prior to conception and pregnancy.

BHIVA guidelines recommend that women already on treatment at conception remain on HAART throughout and after their pregnancy.

Some drugs, notably efavirenz (EFV), are not recommended for use during pregnancy.

Loveleen Bansi and colleagues from the UK CHIC Study and the National Study of HIV in Pregnancy and Childhood (NSHPC) analysed clinical and treatment patterns of women conceiving their first child on HAART between 1996 and 2008 using linked data from the two datasets.

The investigators found 1838 matches between the women in the current UK CHIC (n=8,659) and NSHPC (10,912) datasets. Of these, 821 (45%) had received HIV clinical care before their first pregnancy.

The majority of women were infected via heterosexual sex (88%) and over two-thirds (69%) were of black-African ethnicity. Their median age at delivery was 33 (IQR: 28-36) years.

Just over half, 440/821 (54%) women were receiving HAART at the time of conception of their first child.

Their median CD4 count at conception was 389 (IQR 270-554) cells/mm3. Amongst women who had a measurement up to 90 days before conception, 88 (27.9%) had a detectable viral load >50copies/mL.

Of the 440 women, 237 (53.9%) received an NNRTI and for 86 (19.5%) women this was EFV. Most women had not started treatment close to conception, 40.9% had already been on HAART for over 3 years and only 10.9% started less than 6 months before conceiving.

One-third (n=155 (35.2%)) made a switch in their regimen before delivery. The proportions of women switching therapy by 3 and 6 months of conception were 22% and 33%. Of those receiving EFV at conception, 37 (43%) of women switched this drug.

The vast majority (97%) of women receiving HAART at conception were also receiving HAART at delivery. After delivery 286/428 women switched regimen at a median of 15 (IQR 13-18) months.

The proportions of women switching regimen at 6, 12, 18 and 24 months were 27%, 41%, 55% and 61%, respectively. In the year following delivery 13 (13%) of women receiving HAART at delivery discontinued completely.

The investigators wrote; “ Adherence support is important after pregnancy to minimise the number who interrupt or stop treatment after delivery.”

comment

The authors of this poster noted (personal correspondence) that they don’t have information on when the woman found out she was pregnant, in relation to conception (or when she told her clinician).  So, for women who were already on efavirenz at the time of conception, if they didn’t find out they were pregnant until a few months into the pregnancy, it might be argued that any potential damage had already been done, and so there was less reason to switch.

The study also highlights the importance of post natal adherence support.

Ref: Bansi L et al. Use of antiretroviral therapy during and after pregnancy among HIV-infected women already aware of their infection before conceiving. 2nd Joint Conference of BHIVA with BASHH, 20–23 April 2010, Manchester. Poster abstract P154.

Longer duration of rupture of membranes (ROM) was identified as a risk factor for mother to child transmission (MTCT) in the 1990s. Elective caesarean section prior to ROM was found to be protective.  However, these studies were conducted before the availability of HAART.

Whether duration of ROM has clinical implications for women on effective HAART is unclear. An increasing number of women in the UK opt to deliver vaginally but, of these, a high proportion, undergo emergency caesarean section. It is likely that concern over ROM contributes to this management decision.

In an oral presentation at the 2010 BHIVA/BASHH meeting, Pat Tookey showed findings from an investigation, using routine surveillance data from UK and Ireland, to explore the association between duration of ROM and transmission. Surveillance of obstetric and paediatric HIV is conducted through the National Study of HIV in Pregnancy and Childhood (NSHPC). Data on ROM have been collected since January 2007.

In this study, the investigators reviewed pregnancies resulting in live singleton births among HIV-positive women reported in 2007-9.

During this period, 2686 births were reported. The majority (95%) of mothers were on HAART; 40% had an elective caesarean section, 34 had vaginal delivery and 26% emergency caesarean section. Almost Three quarters of mothers (74%) had an undetectable viral load and the rate of mother to child transmission was 0.9% (15/1697).

Of the total, 1063/2686 mothers had an elective caesarean and data were missing for 298. There were ROM data for 1325, of which 884 (67%) had ROM prior to delivery and data on duration was provided for 661 (75%). The median duration was 4 hrs (IQR 1.5-8), <6hrs for 444 (67%), >6-48 hrs for 217 (33%), this included 16 mother with >48 hrs ROM.

There were 6/421 (1.4%) transmissions overall, among the infants with confirmed HIV status. The rate was similar for infants with < 6 hrs ROM, 2/284 (1.4 compared to those with  >6 hours, 2/137 (1.5%), OR 1.0 (95%CI 0.2-5.7, p=1.0)

In the sub group of women with undetectable viral load (<50 copies/mL) near delivery (99.7% on HAART), there was no difference in MTCT (overall 1/341, 0.3%), between those with ROM for >6 hrs compared to <6 hrs (0/112, 0.4% vs 1/229, 0.0%, p=1.00). Likewise, among mothers with undetectable viral load who had a planned vaginal delivery (overall 1/203, 0.5%:  0/52, 0% vs 1/151, p=1.0).

Six of the 661 children had confirmed infection at the time of analysis including 3 likely in utero transmissions (positive PCR on Day 1, see Table 1).

Table 1: Six children infected with HIV who were born to women with ROM before delivery

* closest to delivery. Note: Patients 1, 5 and 6 had reported adherence issues.

The investigators concluded that although data are sparse to date, so far there is no evidence that among women on HAART longer duration of ROM is associated with an increased risk of MTCT. Larger sample sizes are required and comprehensive data on: ROM and duration of ROM, infant infection status and viral load close to delivery. Continuing monitoring is essential.

Ref: Haile-Selassie H et al. Duration of ruptured membranes and vertical transmission of HIV: data from national surveillance in the UK and Ireland. 2nd Joint Conference of BHIVA with BASHH, 20–23 April 2010,  Manchester. Oral abstract O2.

There is little research and information reported on young women growing up with HIV. But a study at the meeting showed some interesting data on the pregnancy outcomes of young women who were born with HIV 10–20 years ago. The study looked at a cohort of 172 women, born with HIV and accessing services in 19 centres across the UK and Ireland.

Overall, there were 36 pregnancies reported in 27 women, with a median age of 18 years at first pregnancy. Of these, 27 (75%) were unplanned, 7 (19%) were planned and 2 were unknown. The women all conceived before September 2009. Seventeen women were on HAART, with a median CD4 count of 244 cells/mm3, but 8 out of the10 women who were not on treatment had CD4 counts below 200 cells/mm3.

Of the reported pregnancies, 86% (31/36) were with regular partners, of whom 22 (61%) reported being unaware of their partners HIV status. The pregnancies resulted in 5 (14%) 1st trimester miscarriages, 9 (25%) elective terminations, 18 (50%) live births and 4 (11%) pregnancies were ongoing.

At the time of delivery, 89% of the mothers were on HAART, with a median CD4 count of 254 cells/mm3 and a median viral load of 79 copies/mL (range <50–580,000). Seven women delivered with viral load <50 copies/mL, four had VL >1,000 copies/mL. Two women were admitted for Directly Observed Therapy and two were non-adherent to HAART at delivery. Mode of delivery was 9 elective and 5 emergency C-sections with 4 vaginal deliveries. 6 (33%) infants delivered at <37/40, five of whom required Neonatal Intensive Care. None of the babies were infected and there were no congenital anomalies were reported. Five of the babies were fostered and 3 have ongoing concerns.

The study showed without a doubt, that prevention of mother to child transmission worked, even though some mothers had advanced HIV and were not well adherent. Additionally, the study also highlighted a worrying high number of unplanned pregnancies, a population with social needs despite access to contraceptive services.

Ref: Williams B et al.  Pregnancy outcomes in women growing up with HIV acquired perinatally or in early childhood. 2nd Joint Conference of BHIVA with BASHH, 20–23 April 2010, Manchester. Poster abstract P144.

The mechanism for high rates of hepatitis C (HCV) transmission in HIV-positive gay men is unknown with little data on whether HCV levels in semen had a similar risk factor to HIV viral load, especially during acute infection.

Joanna Turner and colleagues presented a key study to inform this field.

Paired blood and semen samples were collected from 5 acute and 9 chronic HCV cases in HIV-positive men. At baseline 0/5 acute and 2/9 chronic cases had detectable HCV RNA in semen. Of all samples tested 2/10 (20%) of acute cases and 4/23 (17%) of chronic cases (p=NS) had detectable HCV RNA in semen.

However, when detected, HCV RNA viral loads were low: <30 IU/ml (acute cases) and <230 IU/ml (chronic cases) and did not correlate with plasma HCV viral load

Taken together, this lead the researcher to suggests that the quantity of seminal HCV virus is not a significant factor in determining the rate of HCV transmission, even during acute infection. Recruitment to the study is ongoing.

Ref: Turner J et al. Hepatitis C viral load in semen of HIV-positive men during acute and chronic hepatitis C infection. Oral abstract O5

Although the interpretation of the role HIV and vitamin D deficiency remains a focus in HIV-positive populations in relation to reductions in bone mineral density in adults, the impact on children is potentially more worrying.  If HIV-related complications prevent optimum bone development earlier in life (generally until the age of 30), this could result in higher rates of bone complication in later in life.

Atkinson and colleagues presented results of such low vitamin D levels in HIV-positive children that suggest further research should be an urgent priority.

An audit of plasma bone biochemistry, 25(OH) vitamin D and PTH levels in a cohort of 131 HIV-positive children receiving routine clinical care at a single UK centre between January and December 2009.  Median age was 12 years (IQR 9, 15); 51% were female and 85% were African/Caribbean. Median CD4 count (%) was 760 (32%) and 104 children (79%) were on HAART.

64 children (49%) were deficient (defined as 25nmol/L) and a further 37 (28%) had insufficient levels (25-50nmol/L). Abnormal PTH (>6.8 pmol/L) was seen in 15/52 children who had these levels (28.9%).

In multivariate analysis 25(OH) vitamin D deficiency was associated with older age (p=0.001), African/Caribbean ethnicity (p=0.04), winter season (0.008) and NNRTI use (P=0.01).

The authors concluded that Vitamin D deficiency and insufficiency is very common in children with HIV. Maximising bone health is increasingly important as this population enter adult life and the role of vitamin D supplementation requires further elucidation.

Ref: Atkinson S et al. Vitamin D deficiency in children with perinatally acquired HIV-1 infection living in the UK. Poster abstract P159.

The first ever ‘late breaker’ presentation for a BHIVA meeting was included to report a rapid increase in the number of cases of Lymphogranuloma venereum (LGV) reported to the Health Protection Agency (HPA) over winter 2009/10.

Diagnoses were 91% higher for November 2009 to January 2010 than in the previous three months (88 vs 46 cases), and 115% higher than that seen in the same period in 2008/09 (41 cases).

Since 2004, outbreaks amongst MSM have occurred in major cities in Europe, with 1,070 cases in the UK, mainly in London and to a lesser extent in Brighton and Manchester. LGV, which is caused by the L serovars of Chlamydia trachomatis, is endemic to areas of Africa, Asia, South America and the Caribbean.

The understanding of the epidemiology and mode of transmission of LGV remains poor, with only a small number of asymptomatic cases detected. Urethral infection is uncommon and, whilst infected individuals have high risk sexual behaviour and links to sex toys and sex parties have been described, no definitive associations have emerged.

Unlike other forms of C. trachomatis, LGV is invasive. Most cases seen in the UK have presented with proctitis but symptoms vary according to the site of infection and may include ulcers and inflamed and swollen lymph nodes in the groin (inguinal syndrome). If left untreated symptoms can become more severe and cause lasting damage to health. Treatment with three weeks of doxycycline BD 100 mg is recommended by BASHH.

Information posted to the HPA website, includes the following recommendations for limiting further spread.

• Testing for LGV should be offered during routine clinical care to HIV positive MSM who have symptoms of LGV infection and have a positive test for C. trachomatis;
• MSM should have a full sexual health screen annually. This should include testing for HIV where it is not already diagnosed;
• Behavioural modification is a key component of control strategies. Campaigns that increase awareness and knowledge of STIs and promote safer sex need to be intensified.

Several posters at the conference related to LGV.

Pallawela and colleagues from five clinics in London and Brighton presented results from a six-month pilot screening programme in 98 men who were newly diagnosed with HIV, HCV or syphilis and who were routinely offered testing for urethral and, if indicated, rectal Chlamydia. [2]

Of the 82 men (84%) who were screened within 4 weeks, 40 (49%) were newly diagnosed with HIV, 36 (44%) with syphylis and 8 (10%) with hepatitis C. Rectal Chlamydia was diagnosed in 13/82 (16%), of whom one also had urethral Chlamydia, and two with urethral Chlamydia only. No cases of LGV were found.

Dosekun and colleagues from St Thomas’ Hospital, London, which was also one of the five centres reported above, included a case report of pharyngeal LGV in a 26-year old HIV-positive gay man. [3]

He presented in April 2009 with rectal discharge and constipation, but reported no symptoms of urethritis or sore throat. Sexual history included recent protected anal and unprotected oral receptive and insertive sex with casual male partners. He was on antiretroviral therapy with a CD4 count of 627 cells/mm3 and undetectable viral load (<40copies/mL).

On examination he had florid proctitis with haemopurulent exudate. A rectal swab was positive for Chlamydia trachomatis (CT) and pharyngeal swab showed an equivocal CT result. Both specimens had LGV-specific DNA detected in laboratory analysis.

He was treated for proctitis with cefixime 400mg stat and a 21-day course of doxycycline 100mg bd. His rectal symptoms resolved with treatment and a pharyngeal CT test of cure at 6 weeks was negative.

Although most cases have been rectal, the authors reported this as the first documented case of LGV- associated CT DNA detected from the pharynx in the current UK outbreak. Reported risk factors for LGV acquisition suggest that transmission is predominantly rectal-to-rectal via intermediate carriage on hands or fomites. This case highlights possible transmission via orogenital contact.

References:

1.   Substantial increase in cases of Lymphogranuloma venereum (LGV) in UK. Oral late breaker.

See also online HPA report:

http://www.hpa.org.uk/hpr/archives/2010/news0810.htm#lgv

2.   Pallawela S et al. Screening for asymptomatic LGV coinfection in MSM newly diagnosed with HIV, hepatitis C or infectious syphilis. 2nd Joint Conference of BHIVA with BASHH, 20–23 April 2010, Manchester. Poster abstract 187.

3. Dosekun G et al. Case report: asymptomatic LGV detected from the pharynx of a London MSM. 2nd Joint Conference of BHIVA with BASHH, 20–23 April 2010, Manchester. Poster abstract 203.

Bone disease was addressed in many of the posters, with the first of these reports coming from Guys and St Thomas’ and the remaining three from the Chelsea and Westminster Hospital.

Perry and colleagues from reported results of a cross-sectional study of 175 randomly selected HIV-positive patients who completed lifestyle and general health questionnaires that were compiled with biochemical analyses and DEXA lumber spine and hip. [1]

Baseline characteristics included median age 38 years (IQR 30-43); 64% male, 41% black, 85% ARV-experienced, 31% current smokers.

DEXA results showed 49% patients had reduced BMD, 13% with osteoporosis and 36% with osteopenia. Age increased the association (p=0.007) occurring at a median age of 44.50 years (IQR 38–51 years) but not gender, with osteoporosis diagnosed in approximately 10% of patients aged 40-49 and 20% in those aged >50 years. (See Table 1).

Table 1: BDM results by gender and age

In multivariate analysis, other risk factors were low BMI (OR 0.87; 95%CI 0.79–0.95; p= 0.003) and ever having been on HAART (OR 4.43; 95%CI 1.57–12.50; p= 0.005). Gender, ethnicity, HIV viral load, CD4 cell count, CD4 cell count nadir and vitamin D were not statistically associated with abnormal BMD.

In their conclusion the authors highlighted the high proportion of patients with HIV from young age groups, and a significant correlation with HAART and that this may provide a rationale for routine screening for risk factors that predict fracture in HIV, including low BMD.

Stuart-Buttle and colleagues reported results from a retrospective audit of 106 patients who had DEXA scans from 2007–2009. [2]

12% had osteoporosis, 30% had osteopaenia and 58% had normal DEXA scans. Of the 44 patients over 50 (mean age 58.1 +7.02), 36% had a diagnosis of osteoporosis and 41% had osteopaenia, compared to 28% and 5%, respectively, in the group under 50 years.

While this was a retrospective study, presumably in patients selected for DEXA bone concerns, the researchers concluded that HIV should be considered a risk factor and that including HIV-positive people >50 years need to be included in screening studies. No significant correlation between bone mineral density and CD4 count, calcium or vitamin D levels.

Hughes and colleagues presented results from a new ‘over 50s clinic’ that was set up in January 2009. Of 54/70 patients with DEXA results (4 patients were excluded due to with diagnosed bone disease), osteopaenia was diagnosed in 24% (13/54) and osteoporosis in 11% (6/54). Of these, 77% (10/13) with osteopaenia and 100% (6/6) with osteoporosis were male. [3]

The mean age was 60 years, 93% (50/54) were male and 85% (46/54) of white ethnicity. All patients were taking ART (100% VL <50, mean CD4 551 cells/mm3).

Low vitamin D levels occurred in 66% (4/6) with osteoporosis, 38% (5/13) with osteopaenia and 49% (17/35) with normal DEXA result. With over one third of this cohort with osteopaenia or osteoporosis, the authors concluded that this supported routine screening in individuals aged over 50.

Finally, Rashid and colleagues, prospectively measured Vitamin D levels (25(OH) vitamin D) in 312 patients in July 2009. [4]

Mean age was 48 years (range 25-83), 88% male, mean duration of HIV infection 12 years (range 0-26). Median vitamin D level was 66nmol/L (range <10-221) with 35% levels low (40-70nmol/L) and 21% deficient (<40nmol/L). Low Vitamin D correlated with non-caucasian ethnicity (p<0.001) and female sex (p<0.001), but not antiretroviral class or specific agent, including efavirenz.

Of note, in 102 patients (33%) who had DEXA scans for unrelated reasons, median vitamin D levels were 71, 71 and 58 nmol/L for those with normal, osteopaenic and osteoporotic results respectively.

The lack of association of low vitamin D levels with DEXA results, and also with alkaline phosphatase levels, suggest the importance of larger definitive studies to inform patient management in this area.

References

All references are to the Abstracts of the 2nd Joint conference of the BHIVA and BASHH, 20–23 April 2010, Manchester.

1. Perry M et al. The relationship of HIV and bone density: implications for screening. Poster abstract P44.

2. Stuart-Buttle  C et al. Screening for bone disease in HIV patients. Poster abstract P46.

3. Hughes A et al. Over 50? It’s time for a dual energy x-ray absorptiometry (DEXA) scan. Poster abstract P39.

4. Rashid T et al. No association of vitamin D levels with individual antiretroviral agents, duration of HIV infection, alkaline phosphatase levels or bone mineral density findings. Poster abstract P45.

Many other studies at the conference deserve further reporting but can only be briefly summariesed here. For full details please refer to the conference abstracts and contact the lead authors.

Transmission and late diagnosis in older people: half of late diagnoses in people over 50 years old

An oral presentation from the Health Protection Agency highlighted some aspects of how older people are affected by HIV. The number of older adults who are HIV-positive in the UK from 2333 in 2000 to 8268 in 2007, accounting for 16% of adults accessing care in 2007 and 8% of all HIV diagnoses between 2000–2007. [1]

Compared to younger adults, newly diagnosed adults aged 50 years and over were more likely to be men (74% vs. 58%; p<0.001), infected through sex between men (40% vs. 34%; p<0.001) and of white ethnicity (60% vs. 38%; p<0.001). Older heterosexuals adults were more likely to be infected within the UK (16% vs. 12%; p<0.001), with evidence of travel abroad amongst white heterosexual men.

Late diagnosis (CD4 count <200) was significantly higher amongst older adults (48% vs. 33%; p<0.001); with older MSM being twice as likely to present late than younger MSM.

This study estimated that nearly half (48%; 1486) of persons diagnosed between 2000 and 2007 acquired their infection aged 50 and over.

Ref: Smith R et al. Refocusing our efforts – transmission and late diagnosis of HIV among adults aged 50 and over. Oral abstract O3.

Ocular syphilis at first presentation of HIV

Three cases were described where ocular syphilis was the presenting symptom: a 33-year old heterosexual man, a 20-year old gay man, and a 39-year old gay man. The study concluded: “Syphilis should be excluded in cases of uveitis and optic neuritis; other features of secondary syphilis may be absent. All patients had improving visual symptoms after neurosyphilis therapy, and had preceding oral steroids to prevent Jarisch-Herxheimer reaction, as this can worsen ocular symptoms. Early diagnosis is important as ocular syphilis can rapidly cause blindness.

Ref: Dhairyawan R et al. Ocular syphilis as the first presentation of HIV infection. Poster abstract P132.

Perinatally infection diagnosed in late adolescence

Two cases of extremely late diagnosis, in a young man and woman, both 20-year old Ugandan patients, presenting with multiple complications, including HIV-related dementia. These rare cases highlight the importance of family history and HIV testing in children and young adults who were potentially exposed to HIV during pregnancy and at birth.

Ref: Ross S et al. Vertical HIV infection in young adults presenting with HIV-associated dementia. Poster abstract P169.

Summary reports from this workshop included below have been selected from a comprehensive report from the Liverpool pharmacology group.

The full report is available in PDF format:

http://www.hiv-druginteractions.org/new/Uploaded_Attachment/82_11%20PKW%20Sorrento.pdf

Reports in this issue include:

• Atazanavir absorption maximised with food
• Methadone levels reduced moderately by rilpivirine
• Maraviroc 150mg once-daily achieves target concentrations with atazanavir/ritonavir
• Raltegravir and unboosted atazanavir
• Raltegravir dose adjustment not required for patients on dialysis
• Raltegravir and darunavir pharmacokinetics in liver disease
• Tenofovir may require closer renal monitoring in older patients
• Effect of age on atazanavir, darunavir, raltegravir and etravirine
• TDM targets for raltegravir
• Impact on billirubin levels when atazanavir is dosed twice-daily

Selected abstracts and presentations from the 2010 workshop are now on the Virology Education website:

http://regist2.virology-education.com/11th/7_april.html

The impact of food on atazanavir/ritonavir (300/100mg once-daily) was assessed in 12 HIV-positive volunteers. When given without food, atazanavir AUC, Cmax and Ctrough decreased by 41%, 32% and 53%, respectively. Ritonavir AUC and Ctrough decreased by 26% and 53%; Cmax increased by 4%. One patient had atazanavir Ctrough below target (<150 ng/mL), but no patients showed evidence of virologic failure.

comment

This study indicates that food maximises the absorption of atazanavir and supports the recommendation to take atazanavir/ritoanavir with food.

Ref: Giguerre P et al. The effect of food on the pharmacokinetics of atazanavir/ritonavir 300/100mg daily in HIV-infected patients. 11th PK Workshop, 2010. Abstract 30.

The effect of TMC278 (25 mg once daily) on the pharmacokinetics and pharmacodynamics of methadone was studied in 13 HIV negative volunteers stable on methadone maintenance therapy (60-150 mg/day).  TMC278 decreased the AUC, Cmax and Cmin of active R-methadone by 16%, 14% and 22%, respectively. Decreases were also seen in the AUC (16%), Cmax (13%) and Cmin (21%) of inactive S-methadone.  Exposure of TMC278 in the presence of methadone was within the expected range. No signs of opiate withdrawal were observed.

comment

Although no a-priori dose adjustment of methadone is required, clinical monitoring for withdrawal symptoms is recommended as some patients may require dose adjustment.

Ref: Crauwels HM et al. Pharmacokinetic interaction study between TMC278, a next-generation NNRTI and methadone. 11th PK Workshop, 2010. Abstract 33.

The pharmacokinetics of maraviroc (150 mg once daily) and atazanavir/ritonavir (300/100 mg once-daily) were assessed in a pharmacokinetic sub-study of 15 HIV-positive volunteers.  All subjects achieved, or exceeded, the targeted maraviroc Caverage of 75 ng/ml. Steady state values for maraviroc AUC, Cmax and Cmin were 4330 ng.h/ml, 650 ng/ml and 37 ng/ml, respectively. Efficacy and safety of this combination are currently being evaluated.

Ref: Vourvahis M et al. Pharmacokinetics of QD maraviroc co-administered as part of a novel NRTI-sparing regimen with atazanavir/ritonavir in HIV treatment-naïve patients. 11th PK Workshop, 2010. Abstract 37.

Coadministration of raltegravir (400 mg twice daily) and unboosted atazanavir (300 mg twice daily) was studied in 22 HIV-positive volunteers. Raltegravir pharmacokinetics were compared to historical data from HIV-positive volunteers receiving 10 day raltegravir monotherapy.

Raltegravir geometric mean AUC with atazanavir was 6166 ng.h/ml and was comparable to historical controls (6851 ng.h/ml). Atazanavir exposure showed high inter subject variability with a geometric mean AUC of 14622 ng.h/ml and a CV of 68.3%. Linear regression showed a highly significant correlation between raltegravir AUC and atazanavir AUC: subjects with atazanavir AUC >14622 ng.h/ml had a two-fold increase in raltegravir AUC. A similar trend was observed for trough concentrations.

Overall, unboosted atazanavir did not significantly increase raltegravir exposure, although subjects with higher atazanavir exposure had higher raltegravir concentration.

comment

Raltegravir pharmacokinetics are variable and this is a cross study comparison; therefore we need to be cautious in interpreting the data.

Ref: Cattaneo D et al. Exposure-related effects of unboosted atazanavir on the pharmacokinetics of raltegravir in HIV-1 infected patients. 11th PK Workshop, 2010. Abstract 49.

The effect of haemodialysis on raltegravir clearance was evaluated in two anuric end stage renal disease HIV-positive patients.

Predialyzer (C_in) and postdialyzer (C_out) blood samples were collected at the beginning and end of a single 4 h dialysis session and the haemodialysis extraction ratio (ER) was calculated using (C_in – C_out)/C_in.  Raltegravir dialysis clearance (CLd) in terms of plasma was calculated using ER x Qp, where Qp is plasma flow through the dialyzer.

At the end of the session, raltegravir concentrations decreased by 68% in patient 1 and by 45% in patient 2. However, ER and CLd were only 5.5% and 9.1 mL/min in patient 1, and 9.5% and 19.1 mL/min in patient 2, respectively. Both patients maintained raltegravir concentrations higher than 15 ng/mL at the end of the dialysis session.

comment

These results show minimal removal of raltegravir by haemodialysis and dosage adjustments of raltegravir may not be required.

Ref: Molto J et al. Effect of hemodialysis on raltegravir clearance in HIV-infected patients with end stage renal disease.11th PK Workshop, 2010. Abstract 7.

The pharmacokinetic profiles of darunavir and raltegravir were analysed in five HIV/HCV coinfected patients with moderate to severe liver disease. Based on the ultrasonographic and histological evaluation, two patients had HCV-related chronic active hepatitis, and three patients had a diagnosis of cirrhosis (Child Pugh stage B). Trough concentrations were determined 14 and 30 days after starting a raltegravir/darunavir containing regimen.

Mean raltegravir and darunavir trough concentrations in the hepatic impairment group was 637 (mean Ctrough in control group: 221±217 ng/ml) and 8519 ng/mL (mean Ctrough in control group: 3236±2183 ng/ml), respectively. In a sub-group analysis, patients with cirrhosis had higher mean raltegravir Ctrough than patients with active non cirrhotic hepatitis (665 vs 581 ng/mL). The mean darunavir Ctrough was consistently higher in cirrhotic than non cirrhotic patients (9820 vs 2016 ng/mL).

comment

The data suggest special caution in the use of raltegravir, and especially of darunavir, in patients with moderate to severe liver impairment because of the risk of additionally increased toxicity.

Ref: Tommasi C et al. Raltegravir and darunavir plasma pharmacokinetic in HIV-1 infected patients with advanced liver disease.11th PK Workshop, 2010. Abstract 10.

The impact of age on tenofovir-related effects on estimated glomerular filtration rate (eGFR) were explored in a retrospective analysis of 1031 HIV-positive subjects receiving tenofovir as part of their antiretroviral regimen.  Serum creatinine values were used to compute eGFR by the MDRD method.

The average eGFR at baseline was 112.7 ml/min and the median age was 43 years.

In a univariate analysis, there was a decrease in eGFR of 0.016 ml/min for each day of tenofovir use, an effect that persisted after controlling for age, baseline MDRD, race and gender. When age was added to a model controlling for days of tenofovir use, eGFR decreased by 0.638 ml/min for each year increase in age.

Individuals >50 years had an average eGFR 16 ml/min lower than individuals <50 years, which reduced to 4 ml/min lower than those <50 years after controlling for baseline eGFR.  When subjects were further stratified by age (<30, 30-45, >45 years), individuals aged 30-45 had an average eGFR 9.54 ml/min less compared to those <30; individuals >45 had an average eGFR 11.9 ml/min less than those <30 years, after controlling for eGFR at baseline.

comment

The authors of this study concluded that tenofovir may require closer monitoring in older individuals.

Ref: Goeddel L et al. Effect of Age on Renal Function with TDF. 11th PK Workshop, 2010. Abstract 38.

Trough concentrations of atazanavir, darunavir, raltegravir and efavirenz were compared in HIV-positive volunteers, grouped according to age (A: ≤39, B: 40-49, C: ≥50 years).  A total of 249 samples were analysed from 134 subjects (28 ATV/r, 40 DRV/r, 47 RAL, 19 EFV).

Atazanavir mean trough concentrations were lower in group C than group A, but this was not statistically significant (1483 vs 1968 vs 1013 ng/ml, A vs B vs C).  Darunavir mean concentrations were similar across the three groups (2633 vs 3077 vs 2581 ng/ml, A vs B vs C), as were raltegravir concentrations (210 vs 263 vs 177 ng/ml, A vs B vs C).  Efavirenz mean concentrations were significantly higher in group C (2950 ng/ml) than in group A (2148 ng/ml) or group B (2097 ng/ml).

No linear correlation between age and concentration was found for any drug.

Clinical studies have shown that the virological response to raltegravir is not linked to trough concentrations, but relates to AUC or “GMall” (geometric mean of all concentrations over 48 weeks).  However, obtaining a full AUC over the dosing interval is not practicable in clinical practice and so the use of alternative measurements were investigated.

Plasma concentrations and full AUCs were obtained from 47 HIV-negative volunteers receiving raltegravir (400 mg).  Trough concentrations were not significantly related to AUC0-12h or GMall.  The best single time point correlation with AUC0-12h was found with C2h (R2=0.815), but a stronger correlation (R2= 0.929) was found with AUC0-3h.

comment

Assuming AUC to be the important PK parameter for raltegravir, then TDM should preferably use C2h or an abbreviated AUC0-3h to estimate reliably AUC0-12h, but these observations should be tested prospectively in a patient data set.

Ref: Burger D et al. AUC0-3h of raltegravir is correlated to AUC0-12h: a novel approach for therapeutic drug monitoring of raltegravir. 11th PK Workshop, 2010. Abstract 41.

The changes in total, conjugated and unconjugated bilirubin were studied in 10 HIV+ subjects who switched from atazanavir 400 mg once daily to atazanavir 200 mg twice daily.

Total bilirubin at Ctrough and AUC24 were slightly increased after switch (31% and 15%, respectively), while maximum total bilirubin was unchanged.  Similar increases were observed for unconjugated bilirubin at Ctrough and AUC24, while maximum unconjugated bilirubin was unchanged.

The increases in bilirubin levels related to the switch from once to twice daily dosing were not clinically significant and the data suggest that the increase in unconjugated bilirubin associated with atazanavir  administration is rapidly reversible.

Ref: Gonzalez de Requena D et al. Bilirubin levels in HIV+ patients switching from atazanavir (ATV) 400 mg QD to ATV 200 mg BID. 11th PK Workshop, 2010. Abstract 42.

The 17th Conference on Retroviruses and Opportunistic Infections (CROI), one of the most important annual HIV meetings, was held this year from 16-19 February. As with previous meetings, much of the conference is published online including all abstracts and webcasts of oral presentations including selected poster discussions.

Making this scientific content available without login or subscription is itself a significant achievement. It is a model for broadening access to medical research to a degree that is currently unmatched by any other meeting.

The webcasts this year include oral presentations, poster discussions, the opening lectures and the pre-meeting set of training workshops for young investigators.

The conference website also includes a searchable abstract database.

We encourage readers to view these lectures directly.

http://www.retroconference.org/2010/Abstracts/38289.htm

http://www.retroconference.org/2010/data/files/webcast_2010.htm

Lectures are also available as audio downloads and podcasts which include slides as audiobooks.

New articles continuing our coverage of this meeting are:

• HIV reinfection cases reported at CROI
• Hepatitis studies: IL28B genetics, HCV survival, FibroScan in acute HCV, MSM reinfection and responses to transplantation
• Poor bioequivalence with crushed and dissolved tablets
• Initial PK, safety and 12 week efficacy of raltegravir chewable tablets in children 6-11 years
• PK of efavirenz in children dosed according to WHO weight bands
• Virological and immunological responses in infants enrolled in the CHER trial
• Darunavir-associated mutations in PI-naive and PI-experienced children in the UK

A poster discussion session included studies looking at different aspects of dual infection and reinfection and included two case studies that showed where this had a clinical outcome. Two other studies, one from London and one from San Francisco, reported on aspects of dual infections.

Erika Castro from University of Vaudois Hospital, Lausanne, and colleagues presented a useful case of reinfection between two men (M1 and M2) who had been sexual partners since 2006. [1]

M1 was initially diagnosed in 2000 during primary infection and had been suppressed on HAART through to 2007 with no history of drug resistance. M2 had been on HAART for five years with detectable viral load (range 3–4 log) and documented triple class resistance. In February 2008, viral load in M1 rebounded to 280 copies/mL and continued increasing. Resistance and phylogenetic tests were compared from 2000 and 2008 (86 sequences:  whole-genome (n=28), env (n=28), and gag (n=25).

All sequences were sub-type B. The genotypic analysis from 2008 showed 25 new related drug resistance mutations in M1 (11 in RT and 14 in protease), of which 23 were also present in M2. Additionally, M1-2008 sequences clustered within the M2-2008 branches and distinct from M1-2000 sequence clusters in all trees. Recombination between the original M1 and M2 strains was not observed, with M1 being replaced with M2 sequences following superinfection.

The case is important for highlighting several aspects of HIV reinfection:

• That reinfection can occur in established infection.
• That it can occur between regular partners (that no immune protection develops to repeated exposure to one virus).
• That reinfection can occur after several years of exposure (as with initial infection, chance and probability are low).
• That there is a clinical risk from reinfection when partners have different resistance profiles (most reinfection cases are only discovered because of unexplained viraemia in stable patients).
• That ART did not offer protection against reinfection, probably because any PEP effect would be negligible if the new MDR virus was resistant to the ARVs in that combination.

Martine Braibant from University de Tours Hospital and colleagues presented another case of sub-type B being reinfected with subsequent sub-type B infection. [2]

This patient entered a long-term non-progressor (LTNP) cohort in 1995 aged 58, following a ten year history of HIV infection, with a CD4 count >600 cells/mm3 for the previous 5 years and viral load of 135 copies/mL on study entry. From 1995–1999, viral load slowly increased to around 10,000 copies/mL and CD4 count dropped steadily to <500 cells/mm3. The initial infection was found to have a 20 nucleotide deletion in nef (consistent in 28 sequences) and the loss of viral control and immunologic progression from 1995 was associated with detection of subsequent sequential reinfection with two fully competent phylogentically different strains. Both new strains were also sub-type B.

The patient responded well to HAART, achieving viral suppression and CD4 recovery >700 cells/mm3 within the first year of therapy, but potentially would have maintained the option to remain off-treatment for many years if reinfection hadn’t occurred.

This case highlighted that:

• Progression rates may be determined by both virologic and immunologic factors
• Reinfection in the absence of resistance may have clinical implications on disease progression, requiring earlier treatment
• That long-term exposure to low level sub-type B virus did not promote an immune response that was protective of subsequent sub-type B infections,

The authors highlighted in their conclusion that this last point showed the inherent difficulties for development of a preventative vaccine.

Jane Deayton and colleagues from St Barts Hospital, London report three cases of inter-clade dual infection detected during routine genotype testing. The three cases were Caucasian UK-born MSM whose only risk factor was sexual exposure in the UK. Case 1 had been diagnosed in 2001 and received a genotype test in 2008 prior to starting therapy that indicated dual infection with sub-types B and G. Cases 2 and 3 were tested after their HIV diagnoses in 2007 and 2008 and showed dual infections with B and CRF02_AG, and B and A, respectively. Both these patients were reported to be stable off treatment.

None of the cases included significant drug resistance mutations.

The authors concluded that these were the reports of cross-clade dual infection from sexual transmission in MSM in the UK are rare (only one other was known). Additionally this indicated onward transmission of clades associated with African epidemics and an increasing cross-over of viruses between different demographic groups.

Finally, Larry Bragg and colleagues in San Francisco presented a poster looking at cases where majority viruses change in an individual though competitive expression following dual infection. Whilst difficult to distinguish from superinfection (ie reinfection after an initial infection) sequential expression of dual infections (SEDI) theoretically could come from dual initial infection or reinfection shortly after initial infection, especially prior to seroconversion. [4]

The group included 220 recently infected persons with at least two genotypes (560 person-years of follow-up). The mean age was 37 and median time from infection to first test was 107 days. Divergent viruses appeared in 7 cases, an overall incidence density of 1.24/100 person-years.

Their model estimated a risk of SEDI that was 16-fold higher in the first year post-infection compared to after one year. The estimated rate of SEDI was 4.1/100 person-years (95% CI, 1.8 to 9.2) in the first year following infection and was 0.2 per 100 person-years beyond 1 year post-infection (95% CI, 0.03 to 1.8).

This study highlighted that in the case of dual infection or early reinfection the predominant infection is determined within the first year.

References

1. Castro E et al. HIV-1 superinfection with a drug-resistant strain in a patient successfully controlled with ART. Poster abstract 480.

http://www.retroconference.org/2010/Abstracts/37374.htm

2. Braibant M et al. Disease progression after intrasubtype superinfection in an HLA-B57+ asymptomatic LTNP initially infected with a nef-defective HIV-1 strain. Poster abstract 302.

http://www.retroconference.org/2010/Abstracts/38615.htm

3. Deayton J et al. Inter-clade dual HIV-1 infection: an emerging phenomenon. Poster abstract 447.

http://www.retroconference.org/2010/Abstracts/38460.htm

4 Bragg L et al. HIV-1 Superinfection Surveillance in an Acute Infection Cohort Using pol Sequences from Resistance Genotyping: 1996 to 2008. Poster abstract 446.

http://www.retroconference.org/2010/Abstracts/39292.htm

The following studies focused on aspects of hepatitis coinfection.

IL28 predict treatment response to IL28

Some of the most exciting coinfection studies included those elaborating on the recent association between genetic variations in the IL28B gene and both HCV pathogenesis and response rates to PEG-IFN and ribavirin treatment.

Andri Rauch from University Hospital Bern, introduced the HCV coinfection scientific session with an overview lecture of this research, most of which has become clearer within the last six months. [1]

Rauch detailed how several groups have independently screened the human genome for genetic variations associated with HCV immune response linked to spontaneous clearance or to explain the wide range of responses to HCV treatment: important as roughly 50% patients globally are unable to clear the virus. These studies consistently identified genetic variations in interleukin 28B (IL28B) as the strongest predictor of spontaneous clearance and treatment-related clearance, in both monoinfection and HIV/HCV coinfected individuals.

Rauch explained how IL28B on chromosome 19 encodes interferon-lambda, a type III interferon with antiviral activity mediated through the JAK-STAT pathway by inducing interferon-stimulated genes. Several single nucleotide polymorphisms (SNPs) might modulate function or expression of IL28B.

The correlation between allele frequency in different American ethnicities and treatment outcome was also detailed. The rs12979860 SNP is found in approximately 40%, 70% and 95% of those with African, European and Asian decent, which correlates with SVR rates of 25%, 55% ad 75%, respectively.

IFN-lambda is induced by IFN-alpha and encoded by IL28B, and is not known to play an important role though mechanism in yet to be determined. Phase 1b trials show a potential treatment, synergistic to IFN-alpha, but associated with fewer side effects including reduced fever, flu-like symptoms, neutropenia, bone marrow toxicity.

Together, these findings may enable greater understanding of individual response rates to current treatment, potentially developing management strategies based on genetic differences, and also, potential lead to new antiviral HCV treatments.

Julia di Iulio from University Hospital Lausanne and colleagues presented an analysis of the rs8099917 allele, linked to the Type II haplotype family, in a genome-wide association study involving 347 people with spontaneous HCV clearance and 1015 people with chronic HCV. This in turn lead to identification 21 SNPs, and then four potential causal SNPs closer to IL28B, that are associated with chronic HCV and that may be more likely to influence IL28B function or expression. [2]

Norma Rallon and colleagues from Madrid reported on the role of rs12979860 on treatment responses of 198 HIV/HCV coinfected patients (106 with SVR and 92 non-responders). Due to sampling issues, 164 patients were included in final analysis.

The SVR rate was significantly higher in patients with the CC alleles than in those with CT/TT alleles across all HCV genotypes (75% vs 38%, p<0.0001) and by genotype (G1: 65% vs 30%, p=0.001; G-3/4 83% vs 57%, p=0.02). In the multivariate analysis, the rs12979860 CC genotype was a strong predictor of SVR (OR 3.4; 95%CI 1.4–7.9; p=0.006), independent of other well-known predictors such as HCV genotype 3, baseline serum HCV-RNA <600,000 IU/mL and fibrosis <F3-F4.

Jacob Nattermann from the University of Bonn, and colleagues, reported slightly different results to other coinfection cohorts when they looked at whether IL28B SNP rs12979860 affected treatment outcome in 192 co-infected patients (74 acute and 118 chronic). Rates of sustained virological responses (SVR) were compared in patients carrying different genotypes. As comparison, 136 uninfected and 156 HCV mono-infected patients were included as control groups. [4]

IL28B genotype distribution did not differ significantly between the HIV (acute and chronic) and uninfected groups but monoinfected patients had a low rate of the protective C/C genotype (30% vs 41-47%).

While coinfected patients with the C/C genotype had significantly higher SVR rates than patients with C/T and T/T (58.1% vs 40.6%; p=0.041). This effect reached statistical significance only in HIV-positive patients with chronic (50% vs 29%; p=0.04) but not in those with acute (73.3% vs 60%; p=NS) HCV.

comment

In addition to the data in co-infected patients reviewed by Rauch, his group has also shown that, as in mono-infected patients, polymorphisms also determine spontaneous clearance rates.  The potential for a genetic mechanism to explain differences in spontaneous clearance and HCV treatment response rates by ethnicity is clearly important given the social aspects of HCV care globally. This suggests perhaps a more accurate marker with, or instead of, early treatment response rates, in order to identify people who risk only toxicity without any likely clinical benefit if they use treatment with pegylated interferon and ribavirin.

Clearly, before these tests are utilised in clinical pathways, we need further studies. Positive- and negative-predictive values for genotype results need to be highly predictive to ensure this is not used as a way to exclude some patients from treatment.  IL28 alayses are likely to be included in future treatment studies. Furthermore, there may be implications for the clinical utility of these tests to identify patients with a low likelihood of response to standard therapy who may be candidates for early treatment with specifically-targeted anti-HCV drugs.

Duration of infectious HCV survival in syringes

Elijah Paintsil and colleagues from Yale School of Medicine presented results of the impact that different gauge syringes and different temperatures has on the duration of HCV infectivity and therefore risk from residual blood. [5]

Syringes with low (2 uL) and high (32 uL) quantities of residual HCV-containing blood after full plunger depression, with 1-cc insulin syringe (permanently attached needle) and 1-cc tuberculin syringe (detachable needle), respectively. Syringes were either immediately tested for viable virus or stored at 4ºC, room temperature and 37ºC, for up to 56 days. Virus was recovered from stored syringes and tested for infectivity in cell culture using relative luciferase activity.

HCV infectivity was not detected in the small syringes beyond day one except for those stored at 4º where HCV remained viable in 5% of syringes up to day 7.

After 7 days of storage, 96% ± 7.5, 71%± 23.1, and 52% ± 20 of 32 uL syringes were HCV-positive at 4º, room temperature, and 37º, respectively. Viable virus was recovered from the 32 uL syringes up to day 56. In general, the infectivity of the recovered virus was inversely related to duration and temperature of storage.

Caution when interpreting FibroScan results from acute HCV infection

A study from the European NEAT coinfection group reported that liver stiffness was elevated during acute HCV infection, probably due to high levels of inflammation and short observation periods, and that early FibroScan results should therefore be interpreted with caution, rather than assume that greater stiffness are a marker of rapid progression. [6]

Fibrosis progression rate (FPR) was calculated dividing the difference in fibrosis units by the time of follow-up. The analysis included 28 HIV-positive men with acute HCV that become chronic (91% MSM sexual exposure risk), or if FibroScan prior to anti-HCV therapy was available. Plotting FPR over follow-up time revealed short observation times being strongly correlated with high fibrosis progression rates. No interaction of risk factors for cirrhosis or HAART exposure with follow-up time was observed.

The authors concluded: Calculated high fibrosis progression rates after acute HCV infection in HIV-positive individuals are probably influenced by short observation periods. Higher liver stiffness in the acute phase of HCV infection may be at least partially explained by higher inflammatory activity that has been shown to increase stiffness leading to overestimation of fibrosis. A linear model for fibrosis progression, as is currently applied in the setting of chronic HCV infection, should be used with caution in the setting of acute HCV infection.

HCV reinfection after spontaneous HCV clearance

A poster on acute HCV infection in HIV-positive MSM in Germany was interesting for two reasons. Firstly, 22% patients spontaneously cleared HCV, and secondly, a high rate of reinfection that was reported (5 patients: 17% of those with a spontaneous or treatment related SVR). [7]

Hans-Jürgen Stellbrink and colleagues reported on 46 cases of acute HCV in MSM since 2001, from an HIV cohort of >4,400 predominantly MSM. Incidence rates per 1000 PYFU increased steadily from 0.15 in 2001/02 to 2.48 in 2007/08. HCV was genotype 1, 2, 3 or 4 in 20 (43%), 1 (2%), 9 (20%) and 16 (35%) cases, respectively.

Of the 34 patients treated with peg-IFN/RBV, SVR was achieved in 20 (65% of the 31 subjects with follow-up after treatment), relapse occurred in 3 (10%), and primary non-response was observed in 8 (26%). Ten patients (22%/46) cleared HCV spontaneously, and 2 (4%) remain untreated with persistent infection.

Re-infection occurred in five individuals (17%) of those who cleared acute hepatitis C infection (three with different genotypes, 1 with the same, 1 with pending genotype). After primary infection with G3, one patient developed severe hepatitis upon second re-infection with G1; this patient cleared HCV all 3 times without therapy.

Of note, a 24% rate of spontaneous clearance was reported by Bradley Hare and colleagues in a group of 54 HIV-positive MSM in San Francisco and New York. This study also reported 100% response rates in patients who, having achieved undetectable HCV RNA at week 8 or 12, continued treatment with PEG-IFN only (dropping RBV) for the subsequent 12 weeks. [8]

People with haemophilia with HIV/HCV coinfection need earlier referral for liver transplant

Margaret Ragni and colleagues presented results of canditates for liver transplant from the US multicentre study in people coinfected with HIV/HCV, comparing outcomes in men with and without haemophilia. [9]

Of 100 HIV/HCV enrolled candidates, 33 (33%) underwent orthotopic liver transplantation (OLTX), including 8/16 (50.0%) with haemophilia and 25/84 (29.8%) without.

Men with haemophilia were less likely to still be alive, and more likely to have died before transplant (mainly related to sepsis or multi organ failure). Men with haemophilia reached transplant (OLTX) and MELD of 25 marginally faster than non-hemophilic subjects (p=0.09 and 0.06 respectively). Although younger (42 vs 48 years, p=0.004), there were no differences in BMI, CD4, detectable HIV RNA or detectable HCV VL, time to post-OLTX death, graft loss, and treated rejection or 3-year survival. See Table 1.

Table 1: Outcomes from liver transplant in men with and without haemophilia

The authors concluded that in HIV-positive men with hemophilia, “despite early acquisition of HCV, transplant outcomes appear to be similar to those in co-infected individuals without hemophilia. However, pre-transplant mortality appears higher among co-infected hemophilic men. Whether earlier intervention could reverse this finding is not known”.

comment

Although this was one of the few studies at CROI to mention management issues for people with haemophilia, these results should be interpreted cautiously. With only 16 haemophilia patients in the study who are, by definition, a highly selected group of long-term survivors, the researchers are unlikely to have been able to adjust for the likely differences between the two groups.

References
All references are to the 17th Conference on Retroviruses and Opportunistic Infections, 16-19 February 2010, San Francisco. Oral presentations are included in the webcast: Oral Abstracts and Scientific Overview: Hepatitis C: Transmission, Outcomes, and Treatment. 17th CROI, 2010. Friday 09.30am.
1. Rauch A. The interleukin 28B gene and HCV recovery. 17th CROI, 2010. Oral abstract 162.
http://www.retroconference.org/2010/Abstracts/39872.htm
2. di Iulio J et al. Association of IL28B haplotypes with chronic HCV infection in HIV/HCV co-infected individuals. 17th CROI, 2010. Oral abstract 163.
http://www.retroconference.org/2010/Abstracts/37377.htm
3. Rallon N et al. Strong association of a single nucleotide polymorphism located near the interleukin-28b gene with response to hepatitis C therapy in HIV/HCV co-infected patients. 17th CROI, 2010. Oral abstract 165LB
http://www.retroconference.org/2010/Abstracts/39833.htm
4. Nattermann J et al. Genetic variation in IL28B and treatment-induced clearance of HCV in HCV/HIV co-infected patients. 17th CROI, 2010. Oral abstract 164.
http://www.retroconference.org/2010/Abstracts/39494.htm
5. Paintsil E et al. Survival of HCV in syringes: implication for HCV transmission among injection drug users. 17th CROI, 2010. Oral abstract 168.
http://www.retroconference.org/2010/Abstracts/38965.htm
6. Ref: Vogel M et al. Liver Fibrosis Progression after Acute HCV Infection in HIV+ Individuals. 17th CROI, 2010. Poster abstract 642.
http://www.retroconference.org/2010/Abstracts/38914.htm
7. Stellbrink H-J et al. Incidence, Genotype Distribution, and Prognosis of Sexually Transmitted Acute Hepatitis C in a Cohort of HIV-infected Patients. 17th CROI, 2010. Poster abstract 645.
http://www.retroconference.org/2010/Abstracts/38606.htm
8. Hare B et al. Kinetically Guided PEG Alfa-2a and RBV Therapy for HIV-+ Adults with Acute HCV Infection. 17th CROI, 2010. Poster abstract 639.
http://www.retroconference.org/2010/Abstracts/38114.htm
9. Ragni M et al. Outcomes in HIV/HCV Hemophilic vs Non-hemophilic Transplant Candidates. 17th CROI, 2010. Poster abstract 688.
http://www.retroconference.org/2010/Abstracts/39692.htm

There are limited paediatric antiretroviral options. Despite manufacture labelling, crushing and/or  dissolving tablets, against recommendations, has been reported. Two studies, presented as posters at CROI 2010, looked at bioequivalence of crushed and dissolved Atripla and crushed lopinavir/ritonavir (LPV/r) tablets, compared to whole tablets, in healthy volunteers and HIV-positive children respectively.

Neither strategy met FDA bioequivalence criteria (predefined as, 90%CI 0.8 to 1.25).

Atripla is a fixed dose combination (FDC) tablet combining efavirenz (EFV), emtricitabine (FTC), and tenofovir disoproxil fumarate (TDF).

Use of this FDC is limited to patients who can swallow tablets, since there is no liquid formulation currently on the market.

Jennifer King and colleagues from the University of Alabama looked at the bioequivalence of the FDC tablet and a compounded liquid formulation made from the crushed tablet, dissolved in 5 mL of water and diluted with 20 mL of Ora-Sweet oral vehicle.

This was a randomised, single dose, open label, crossover study in 14 healthy volunteers.

Subjects received single doses of both formulations on an empty stomach separated by a 14-day washout period. Samples were taken pre-dose and 0.25, 0.5, 1, 2, 4, 6, 8, 12, 24, and 48 hours post dose.

The area under the concentration-time curve (AUC-inf) and maximum concentration (Cmax) of TDF, FTC and EFV were determined using noncompartmental methods. Geometric mean ratio (GMR) of liquid to tablet Cmax, AUC-inf, and 90% confidence intervals (CI) were calculated to determine bioequivalence

The mean ± standard deviation age and weight for the subjects were 33.3 ± 10.9 years and 85.7 ± 18.4 kg, respectively.

The bioequivalence geometric means (percent coefficient of variation) and 90% CI for each drug are shown in Table 1.

Table 1: Bioequivalence, geometric mean ratios for EFV, FTC and TDF liquid and tablet formulations (n=14)

The investigators found only the 90%CI for FTC Cmax and AUC fell within the range to meet bioequivalence in this study.

The 90% CI for EFV Cmax was below the range for bioequivalence and AUC above. TDF Cmax and AUC were approximately 40% and 20% higher with the liquid formulation.

The authors suggested careful consideration before crushing Atripla tablets to construct a compounded oral solution.

A related poster authored by Huy Diep and colleagues from the University of California and Children’s National Medical Center, Washington DC,showed data from a PK study to determine the impact of crushing LPV/r on drug exposure in paediatric patients.

LPV/r is recommended for treating HIV-positive children. Although there is an oral formulation, it tastes unpleasant, contains 42% alcohol, needs to be refrigerated and must be taken with food.

The newer film coated tablet formulation of LPV/r does not require refrigeration and has no food restrictions. Although the manufacturer’s instructions state that tablets should not be crushed or chewed, routine use of crushed tablets has been reported.

This was a randomised, open-label, cross over study of 12 patients (13 were enrolled but one child refused to take the crushed dose), age 10-16, already taking LPV/r for at least two weeks.

Two separate 12 hour PK sampling following observed doses of LPV/r 400/100mg either whole or crushed tablets were performed. Samples were taken at 0, 1, 2, 4, 6, 8 and 12 hours. Plasma concentrations of LPV and RTV were measured by HPLC and used to calculate non-compartmental area under the curve (AUC) and clearance (CL/F). Median PK values were compared, using the Wilcox signed rank test. Table 1 shows ratios of crushed to whole tablets.

Table 2: Ratios (90% CI) of crushed to whole tablets

The investigators reported significantly lower exposure after crushed than whole tablets; approximately 40% decreased oral absorption for LPV and RTV. They noted high interpatient variability, eg crushed/whole LPV AUC ratio range: 5-75%.

The extent and variability of reduced exposure after multiple crushed doses at steady state in HIV-positive children remains unpredictable. The investigators concluded that these data reinforce the need to discourage this dosing practice.

comment

Besides emphasising the importance of following the manufacturer’s instructions, these data once again highlight the need for appropriate paediatric formulations.

The development of a liquid formulation of efavirenz has been problematic, but the originator company are continuing with the programme and it is hoped that we will have one soon.

For lopinavir/r, as recommended, dividing tablets clearly is not a good option. Cipla are developing sprinkles using melt extrusion technology to make tiny beads. Bioequivalence studies are underway and this formulation will offer a very useful option to the lopinavir/r liquid.

References

1. King J et al. Assessment of Bioequivalence of Tenofovir, Emtricitabine, and Efavirenz Fixed-dose Combination Tablet Compared with a Compounded Oral Liquid Formulation Derived from the Tablet. 17th CROI, 16-19 February 2010, San Francisco.  Poster abstract 605.

http://www.retroconference.org/2010/Abstracts/37400.htm

2.   Diep H et al. Pharmacokinetics of lopinavir/ritonavir crushed vs whole tablets in children. 17th CROI, 16-19 February 2010, San Francisco.  Poster abstract 877.

http://www.retroconference.org/2010/Abstracts/37445.htm

The raltegravir paediatric programme is ongoing in collaboration with IMPAACT (P1006). Children and adolescents age 2-18 who have failed at least one previous regimen, with viral load >1000 copies/mL are eligible. Age strata are accrued sequentially with the oldest group first.

Acceptable pharmacokinetics (PK), safety and short term efficacy has been reported for 6-11 and 12-18 year olds receiving the adult formulation. (poster 873)

In an oral presentation, Sharon Nachman presented initial PK, 12-week efficacy and safety data (as of January 4 2010) for children age 6-11 receiving a new chewable raltegravir tablet.

In this study, raltegravir was added to the children’s existing antiretroviral regimen. Intensive PK sampling was performed between days 5-12 and then background therapy was optimised.

This was an AUC targeted design for the chewable formulation based on adult data. PK parameters and variability were compared to the adult formulation in children of the same age range.

There were 10 children in this cohort, of which 50% were male, 60% white and 30% black. They were a median of 8.5 years old and 33 kg in weight. Their median absolute CD4, CD4% and viral load were 456 cells/mm3, 22.5% and 4.2 log respectively. The median follow up was 19 weeks.

Initially the dose studied was 8 mg/kg (n = 4). This was reduced to 6 mg/kg because of the high AUC12 with maximum dose of 300 mg.  All dosing was twice daily.

The actual geometric mean (GM) chewable formulation dose was 223 mg (vs 400 mg adult formulation).

At 6 mg/kg, GM AUC12 was 22.6 (range 12.8- 40.6) Mxh (n = 10). GM raltegravir trough (C12h) and peak (Cmax) concentrations were 128 (range 62-397) nM and 10.5 (4-23) uM, respectively.

Raltegravir oral clearance (CL/F) was 21 L/hr for chewable vs 49.6 L/hr for adult formulations. Overall PK variability (%CV) was less for chewable vs adult formulations (AUC12 34 vs 120%; Cmax, 53 vs 130%; C12h 84 vs 221%).

There was one grade 3 adverse event: possibly related (elevated fasting LDL). There were no grade 4 events and no treatment discontinuations. At Week 12, 7/10 children (70%, 95%CI 35% to 93%) had viral load <400 copies/mL (3/7 initially received 8 mg/kg).

The investigators concluded that the raltegravir chewable tablet had less PK variability and lower oral clearance compared to the adult tablet. The differences in clearance are likely to be due to greater relative bioavailability of the chewable tablet.

Study of raltegravir in children age 6-11 will continue with a dose of 6mg/kg (maximum 300mg) of the chewable tablet.

Ref: Nachman S et al. Interim results from IMPAACT P1066: raltegravir oral chewable tablet formulation in children 6 to 11 Years. 17th CROI, 16-19 February 2010, San Francisco. Oral abstract 161LB.

http://www.retroconference.org/2010/Abstracts/39677.htm

Efavirenz (EFV) is used widely in children over 3 years old throughout the world.  To date there is limited information about the steady state pharmacokinetics (PK) of EFV in African children.

A poster from Sabrina Bakeera-Kitaka and colleagues from the ARROW trial showed results from an investigation conducted to determine whether WHO recommended weight band dosing results in optimal EFV exposure in Ugandan children aged 3-12 years.

In this substudy, 41 HIV-positive children receiving generic EFV plus lamivudine (3TC) and abacavir (ABC) were enrolled in a crossover, PK study of twice vs once daily 3TC+ABC. This was conducted 36 weeks after the children started HAART in ARROW.

Children were dosed in accordance with WHO weight bands: 200/250/300*/350*mg for those weighing 10–15, 15–20, 20–25, and 25–30 kg respectively, using EFV capsules or *halved 600 mg tablets. Intensive sampling was performed at t=0, 1, 2, 4, 6, 8, and 12 hours post observed dose on twice-daily HAART at steady state and repeated 4 weeks later including a further 24 hour sample.

The investigators estimated EFV AUC0-24 and clearance (CL/kg) using WinNonlin, and predictors of log10AUC and CL were accessed using multivariate mixed models.

Of the children enrolled, 39 and 37 children had evaluable EFV profiles at the first and second PK sampling respectively.

The children were 41% (16/39) boys, 18 (46%) were aged 3–6 years and 21 (54%) 7–12 years. There were 5, 16, 15, and 3 children in the 10–15, 15–20, 20–25 and 25–30 kg weight-bands, respectively.

The investigators reported geometric mean (%CV) AUC0-24 of 50.4 (91.7%) and 54.0 (80.8%) h.mg/L at the first and second sampling respectively. They found no significant variation across weight-bands (p=0.51).

They noted a large inter- and intra-patient variability in EFV PK parameters (eg 81% and 28% for AUC0-24). They found 15% (6/39) children at the first sampling, and 7/37 at the second (7 children in total) had subtherapeutic C8hr and C12hr levels (<1.0mg/L); 38% (14/37) had therapeutic C24hr levels at the second sampling. They also found 23% (9/39) and 27% (10/37) children in the first and second sampling respectably (11 children in total) with a toxic C8hr and/or C12hr level (>4.0mg/L).

The investigators identified three groups of children using normal mixture modeling:  40% with geometric mean AUC0-24 27.2 h.mg/L, 32% with 49.9 h.mg/L and 28% with 137 h.mg/L. They suggested that genetic polymorphisms might play a role.

Mean clearance overall was 6.8 (SD 3.9) and 6.2 (3.7) L/h at the first and second sampling respectively (p =0.04). C/F increased by 0.50L/h for every year older (p=0.05), but was independent of weight (p=0.85), weight-for-age (p=0.52) or height-for-age (p=0.80).

Overall they found lower exposure than that previously reported in the tablets.

The ARROW group, are conducting ongoing investigations into the relationship between efavirenz concentrations and toxicity. The children’s viral loads will also be tested retrospectively. They wrote: “Increasing the EFV dose for children should be investigated, and has been proposed by WHO. However higher proportions of children with toxic levels might be expected.”

Ref: Natukunda E et al. Pharmacokinetics of efavirenz dosed according to the WHO weight-bands in children in Uganda. 17th CROI, 16-19 February 2010, San Francisco. Poster abstract 878.

http://www.retroconference.org/2010/Abstracts/37642.htm

Avy Violari and colleagues from the CHER trial showed data describing response in young infants after early HAART initiation in South Africa.

Largely because of this trial, current guidelines recommend early treatment in HIV-infected infants and, where possible, infants exposed to nevirapine in prevention of mother to child transmission (PMTCT) should receive lopinavir/ritonavir (LPV/r) first line. There are few data describing virological outcomes in African infants.

In CHER, infants aged 6-12 weeks with CD4% >25% (n = 411) and CD4 <25% (n=40) started LPV/r, zidovudine (AZT), lamivudine (3TC) either immediately or when clinically or immunologically indicated.

In this analysis, the investigators defined virological response as viral load <400 copies/mL and immunological response as CD4% increase >10% from pre-treatment level, at 24 and 40 (or 48 if missing at 40) weeks after starting HAART. Using logistic regression, the investigators examined the association between age at baseline, CD4%, absolute CD4, viral load, weight for age z-score, TB and gender with virological and immunological response. By the end April 2009, 387/451 children had started HAART and had data for >1 outcome.

At baseline, the children were a median: age of 8.4 (IQR 7.1–11.4) weeks; weight-for-age z-score -0.8 (-1.6–0.0); CD4% 32% (24-38%). Over half (59%) had a viral load >750,000 copies/mL. The majority (79%) started HAART by 12 weeks.

At 24 weeks, 71% (95% CI, 65–75%, 246/349) of children had a viral load <400 copies/mL; 77% (245/320) at 40/48 weeks. Assuming loss to follow up as failure, these proportions were 65% and 68% at 24 and 40/48 weeks, respectively.

The investigators found no association between virological response and age at initiation (OR at 24 weeks 1.04 per 4 weeks increase, 95%CI 0.95–1.14, p=0.39), CD4%, weight-for-age z-score, viral load or gender.

Only 5/15 (33%) children with active TB (diagnosed before or within 1 month after initiation) receiving concurrent TB treatment were <400 copies/mL at 24 weeks vs 241/334 (72%) of the remaining children (RR 0.47, 95%CI 0.23–0.96, p=0.04).

Median change in CD4% from baseline was similar at 24 weeks (7%, IQR 1–13%) and 40/48 weeks (7%, 1% -13%). CD4% increase >10% occurred in 33% and 32% at 24 and 40/48 weeks respectively.

CD4% increase >10% was more likely with lower CD4% at initiation. The investigators noted this was the only predictor of immunological response at both time-points.

The investigators concluded: “Virological response was satisfactory in this large cohort of infants initiating lopinavir-based ART in South Africa, and similar to rates reported in infants from well-resourced settings”

They plan to look at suppression in relation to adherence in this trial and resistance in children with detectable viral load.

Ref: Violari A et al. Virological and Immunological Responses in Infants Receiving a LPV/r-based Regimen. 17th CROI, 16-19 February 2010, San Francisco. Poster abstract 843.

http://www.retroconference.org/2010/Abstracts/39129.htm

Katherine Boyd and colleagues from the Collaborative HIV Paediatric Study (CHIPS) and the UK HIV Drug Resistance Database looked at the prevalence of duranavir associated mutations in children.

As duranavir boosted by ritonavir (DRV/r) has the potential for first or second line PI use in the UK, Identifying the prevalence of resistance associated mutations (RAM) in children is important for determining the clinical utility of this drug.

In this study, data from CHIPS (a cohort of approximately 95% of reported HIV-positive children in UK/Ireland since 1996) and the UK drug resistance database from 2000–2007 were combined.

The investigators identified DRV RAM from the 2008 IAS mutations list (V11I, V32I, L33F, I47V, I50V, I54L/M, T74P, L76V, I84V, L89V) and the Stanford database (I47A, G73S/T/C, I84A/C, V82F).

The prevalence of RAM was estimated in both PI and PI-naïve children. Using multivariate linear regression, the investigators examined the time on a PI, the area under the viraemia curve, and the type of PI. They used the Stanford database algorithm to assess the children’s resistance to DRV/r.

Of 344 children tested when they were PI-naïve, 14 (3%) had a single RAM (2 V11I, 2 V32I, 1 I47A, 7 I50V, 1 G73S, 1 L89V). No child had more than one RAM. Of 156 PI-experienced children tested while receiving a PI, 21(13%) had one RAM, 5 (3%) had 2, and 3 (2%) had 3: 55 (35%) children received prior LPV/r only, median (IQR) 2.6 (1.2 to 5.0) years on PI.

In multivariate analysis, there were significant associations between greater number of DRV/r RAM and longer time on a PI (RR 1.14, p=0.04 +1 year), larger area under the viraemia curve since the start of PI (RR 1.78, p=0.01), and previous use of a PI other than LPV/r (RR 6.15, p=0.02 vs LPV/r only).

The investigators noted, only 3 (2%) PI-experienced children had intermediate level resistance to DRV/r using Stanford. They concluded that these results suggest that DRV/r is useful both a first PI and an alternative second PI as prevalence resistance is low.

Ref: Boyd K et al. Prevalence of Darunavir-associated Mutations in PI-naive and PI-experienced HIV-1-infected Children in the UK. 17th CROI, 16-19 February 2010, San Francisco. Poster abstract 851.

http://www.retroconference.org/2010/Abstracts/38696.htm

Persistent HIV infection despite successful ART

Ultimately, we must either acquiesce to treat HIV patients with ART forever, or find ways to definitively prevent infection and to decisively eradicate infection. Tony Fauci, director of the NIH’s infectious diseases institute highlighted these priorities in his keynote address. [1]

Notable at CROI this year were several exhaustive and demanding studies of persistent infection. These were emblematic of the types of studies that are required to make progress in understanding the persistence of HIV infection despite ART, and required if the field is ever going to make progress towards eradication or drug-free control of HIV infection. Both the investigators, and most especially the patient volunteers, are to be applauded for their efforts and contributions.

Mary Kearney co-workers at the Frederick Drug Resistance Program presented very important observations on viral evolution during the initiation of ART. [2]

When a patient initiates ART, suppression of viremia to <50 copies/mL takes many weeks to achieve. It has been unknown to what extent drug resistant populations of virus could develop or expand during this period of time. To carefully characterise genetic diversity and divergence in patients before and during suppressive ART, Kearney and colleagues studied samples from 10 HIV-positive patients taken from the time of ART initiation and thereafter for as long as 5 years. A total of 1300 HIV-1 sequences (gag-pro-pol from p6 to RT) sequences were obtained by single-genome sequencing (SGS). Diversity was measured by average pair-wise difference (APD), genetic variation over time was assessed by phylogenetic analyses and a test for panmixia (the state of maximal mixing of all possible genetic sequences), and sequence changes were characterized using a comparison program called Highlighter.

Before ART, circulating HIV-1 sequences had differences of 0.2 to 2.5% per site. This is consistent with the work of this group and others, showing a relatively homogeneous pool of sequences at a moment in time, with episodic evolution of the circulating swarm in response to immunological pressure. In this group, ART reduced plasma viral RNA levels to undetectable (<75 copies/mL) in all patients within 5 months of initiation. In 8 of 10 patients, phylogenetic analyses and measurements of intra-patient APD revealed no change in viral diversity or population structure between pre- and post-ART samples despite up to 4-log10 decreases in HIV-1 RNA levels. That is to say, that after a 2 log, and a 3 log decline of viral load the residual viral swarm did not change significantly, and no novel viruses were selected or emerged from underneath the majority population. This was still the case when viral sequences were recovered and studied when HIV RNA was <75 copies/mL.

In two patients, divergence of HIV-1 was eventually evident after prolonged ART, resulting in a shift from pre-therapy virus populations containing occasional unique viral variants within a population of a dominant species, to a population with frequent G to A mutations, stop codons, and shifts in CTL escape mutation profiles. In one of these patients, a variant found one day after initiating ART became a predominant plasma clone after fours years on suppressive therapy, similar to that described by Bailey et al. (J Virology 2006). In this patient the predominant plasma clone was significantly different (p<10^-9) from the pre-therapy population by tests for panmixia and divergence (2.9%), resulting primarily from accumulation of G to A mutations.

These results suggest that both short- and long-lived cells are infected with diverse virus populations before therapy, but that viral replication is completely blocked by ART as no evolution of virus is observed during ART-induced decline of viremia. In some patients (as observed in the one patient described above) diverse replication-competent viral variants may decay with long-term suppressive therapy, leaving behind only defective proviruses produced by remaining clones of previously infected cells. This is an alternate or additional explanation for the predominant plasma virus clone described by Bailey, which is hypothesised by some to originate instead from an infected blood stem cell.

Steven Yukl exhaustively examined the HIV burden throughout the gut-associated lymphoid tissue (GALT). [3] He and his co-workers measured HIV DNA (cells that had been infected with HIV in the past) and HIV RNA (produced by infected cells that were potentially expressing HIV viral particles) in different area of the GI tract in patients on prolonged, suppressive ART. Eight HIV-positive patients on ART with CD4 counts >200 cells/mm3 (mean 480 cells/mm3) and plasma RNA viral load <40 copies/mL for 2.8 to 12 years were studied. Blood plasma, PBMC, and 7–10 endoscopic biopsies were taken from sites in the duodenum, terminal ileum, right colon, and rectum.

Using a sensitive research assay, plasma HIV RNA was detectable at very low levels in all patients (median 2.3 copies/mL). Unspliced HIV RNA was detectable in each gut site in the majority (63 to 88%) of patients using RT PCR, but levels were very low. So it is unclear if this HIV RNA represents tiny amounts of RNA produced by many cells, or large amounts of RNA produced by few cells. The latter would seem more likely, and consistent with the occasional ability to visualise HIV RNA by in situ hybridisation. Of course, the presence of HIV RNA does not guarantee that the cells involved are actually producing replication-competent viral particles, although for at least some of these cells that seems also likely to be the case.

Surprisingly, HIV DNA increased from the duodenum to the rectum, and the HIV DNA per CD4+ T cell was higher in all four anatomic regions relative to the PBMCs. Again, it is important to remember that the presence of HIV DNA means only that the virus has entered the involved cell at some time in the past, and does not prove that the cell is producing HIV RNA, or even competent viral particles. It does also not demonstrate that the involved cell was actually infected in the gut site from which the cell was recovered, as immune cells are frequently trafficking in tissues. Biopsies of the GALT, like any assay, are only snapshots in time. The terms persistence and reservoir are temporal and spatial ones, and these observations neither demonstrate that cells stably expressing virus persist in the GALT, or that the events that lead to persistent viral RNA production (and likely virion production) are occurring exclusively in the GALT. But we must measure what is possible to be measured.

Yukl and colleagues noted that the median unspliced HIV RNA was also higher in all gut sites compared to PBMCs, but oppositely was highest in the ileum and lowest in the rectum. Also surprising to the authors was the finding that cell activation markers were lower when HIV DNA levels in the gut tissue were higher. The authors concluded that “The inverse relationship between HIV DNA and T cell activation in the gut and the paradoxically low levels of HIV expression in the large bowel suggest that different processes drive HIV persistence in the blood and gut.”

This study is hopefully the first part of a longitudinal one, as such a study could tell us much of the processes that drive persistence. Persistence can be defined as:

• persistent infection without producer cell death,
• persistent rounds of infection with one cell passing new virus to another, or
• carriage of proviral DNA that can later express replication-competent HIV.

A conclusions from this study is only that cells that are expressing HIV RNA are found more frequently in the ileum. HIV DNA that predominates in the rectal tissue (also the tissue with the lowest levels of immune activation) could be, at least in part, a graveyard of proviral sequences that are incompetent for expression, in cells that were either infected there, or travelled there.

Ann Wiegand presented the results of an NIH intramural group study that found no reduction of persistent, low-level viremia as measured by the single-copy assay (SCA; Palmer J Clin. Micro. 2004) in treatment-experienced who intensified their ART with raltegravir (RAL). [4]

Eight participants had undergone an average of 4 suboptimal regimens with a prior history of virologic failure and genotypic resistance, but who had subsequently suppressed to <75 copies/mL were enrolled. Patients had baseline viral RNA levels determined during a 21-day period prior to RAL intensification, then weekly assays during a 30-day intensification period with raltegravir 400 mg twice daily, and then later additional sampling for 6 weeks after RAL was stopped. There was no significant change in viral RNA levels during intensification or afterwards. Some intensification studies have suggested a CD4 benefit in the absence of a change in viremia, but in this one mean CD4 cell numbers were not significantly different after 30 days of intensification.

Hatano reported the results of a similar study at UCSF in which 15 subjects with undetectable viral loads on ART for at least 1 year were randomised to add RAL 400mg twice daily, and 15 added placebo for 24 weeks. [5]

This was a group with a long disease history: the duration of HIV infection was 18 years, duration of HAART was 23 months, baseline CD4+ T cell count was 232 cells/mm3, and nadir CD4+ T cell count was 53 cells/mm3. Using a SCA with a lower limit of detection of <0.2 copies/mL, median baseline plasma HIV RNA level was 5.2 copies/mL; 9 subjects were below the limit of the assay. The proportion of subjects with undetectable plasma RNA levels at week 12 was not different across the 2 groups. Also, RAL intensification did not alter proviral DNA, cell associated HIV RNA, or CD8+ or CD4+ T cell activation in the blood. Further, 20 patients underwent GALT biopsies, and GALT CD8+ and CD4+ T cell activation was unaffected in the GALT by RAL. In addition, intensification did not significantly affect gag-specific responses in blood or GALT. However, higher levels of gag-specific IL2+INF-gamma CD4+ T cells and CD8+ T cells in GALT were associated with lower levels of cell associated RNA (rho = -0.52, p=0.02 for CD4+ T cell responses; rho = -0.53, p=0.04 for CD8+ T cell responses). This association held regardless of receipt of RAL or placebo, and it is hard to be sure if the association is a marker for patients with better control of tissue viral replication, or whether the responses themselves actually contribute to control of replication.

In a companion piece to this study, Yukl and colleagues also presented a study of the effect raltegravir intensification on HIV RNA and T cell activation in the GALT in patients of suppressive ART. [6]

In this study, 7 HIV-positive men with viral load <40 copies/mL for 3 to 12 years and a CD4 count >200, underwent a variety of 12-week intensifications: raltegravir (n = 4), raltegravir and efavirenz (n = 2), or raltegravir and darunavir/ritonavir (n = 1). Again, GALT biopsies were done in 4 sites (duodenum, ileum, colon, and rectum) at entry and week 12.

As before, HIV RNA was detectable in plasma and PBMCs. HIV DNA was detectable in all GALT sites, and RNA detected in the GALT in most patients. Intensification resulted in no consistent change in HIV RNA in the plasma, peripheral blood mononuclear cells, or gut. There was a trend (in 5 of 7) towards decreased unspliced HIV RNA per 106 CD4+ T cells in the ileum, and similarly a trend towards decreased activation of CD4+ and CD8+ T cells in all GALT sites. The authors concluded that intensification reduced HIV RNA, reduced immune activation, and increased CD4+ T cells in the ileum, suggesting that the ileum may support ongoing productive infection in some patients on ART, even if the contribution to plasma RNA is not discernible. However, like their other study, this study should be followed-up with longitudinal evaluations. Most of the confidence intervals for the effects were wide, and not all the effects were concordant in each part of the GI tract.

Javier Martinez-Picado from Barcelona presented a third raltegravir intensification study actually initially presented last year at CROI and now published in Nature Medicine (March 2010). [7]

69 patients with <50 HIV RNA copies/mL for >1 year were randomised to intensify their ART with raltegravir (n = 45), or to continue their HAART (n = 24) for 48 weeks. As discussed last year, raltegravir intensification resulted in no change or difference in total HIV DNA. This year it was also shown that SCA viremia was unchanged. However raltegravir intensification of a 3-drug suppressive ART regimen resulted in a specific and transient increase in 2-LTR circle DNA in a significant percentage (29%) of ART-suppressed patients, primarily those on therapy that included a PI rather than an NNRTI. This was the same data as shown on a poster at CROI in 2009, but all the individual patient data points were shown. There was no doubt that in the subgroup of patients in the study who had an increase in circles, most followed a similar pattern of increase at week 2 and/or 4, then a decrease to baseline. It should be noted that the levels in most of the 69 patients in the study were <1 copy of DNA circle per million cells, and that in some of the few patients with LTR circles the values were very low and increased little (eg. increase from <1 copies to 6 copies, then decreased to 2 copies) and in others was more variable (eg. 40 copies at baseline, increased to 70 copies at week 2, then <1 copy at week 4).

Interestingly, patients who were 2-LTR+ showed higher levels of immune activation (HLA-DR+CD38+, CD38+CD45RO+, HLA DR+CD45RO+ in CD8 T-cells) at baseline and a decline after intensification. These immune changes appeared quite modest but real, but it was unclear what mechanism induced them. Remember, levels of viremia (by SCA) did not change with intensification, and so the effect of RAL did not reduce the amount of circulating viral antigen – the typical mechanism by which we believe that ART dampens immune activation. The group interpreted their findings as evidence of ongoing replication, but it is important to be picky about terminology here. Replication means full rounds of the HIV lifecycle, which on ART would generally be expected to induce drug resistance. Although this could be happening at a level that is somehow too low to select for drug resistance, there is no evidence for full rounds of replication here. There is evidence for expression of virus (as measured by SCA in some patients), and evidence that RAL had its effect by blocking integration and increasing 2-LTR circles. It would be interesting to know how the individual SCA levels related to the individual 2-LTR circle levels, but this was not shown.

de Laugerre reported on another RAL intensification study for the EASIER-ANRS 138 study team. [8]

There were not obvious technical differences in the implementation of the assays used, but the French group reported “No evolution of HIV-1 total DNA and 2-LTR circles after 48 weeks of raltegravir-containing therapy in patients with controlled viremia” a self-evident title and conclusion. However, the French group did not make measurements at the 2-4 week timepoint after intensification, the time when increased levels of circles were seen by the Spanish.

Several studies examined the effect of the CCR5 antagonist and HIV entry inhibitor maraviroc, as an alternate intensification agent in place of raltegravir. Wilkin reported the results of ACTG 5256 in which patients with suboptimal CD4 recovery after ART added MVC for 24 weeks. [9]

This was a single-arm pilot trial that enrolled patients with a CD4 count <250 celss/mm3, whose CD4 counts were stable despite continued ART such that their calculated CD4 slope was between -20 and +20 cells/mm3/year, despite at least 2 years of undetectable plasma HIV-1 RNA. 34 subjects enrolled in this study. The median baseline CD4 count was 153 cells/mm3 and despite maraviroc intensification a CD4 count increase of > 20 cells/mm3 was not seen. The mean increase in CD4 count to was 11 cells/mm3. Despite this lack of enhanced CD4 recovery, modest decreases in activation (%CD38+ cells, or % HLA-DR+/CD38+ cells) were seen.

Evering and colleagues enrolled patients infected with CCR5-tropic HIV-1 and treated with ART during acute, early infection. [10]

Subjects received ART for an average of 4 years prior to study entry. 4 patients intensified with maraviroc for 24 weeks; 2 patients intensified their NRTI for 12 weeks, followed by crossover to maraviroc for 12 weeks. Phlebotomy and flexible sigmoidoscopy with mucosal biopsies were performed at entry, weeks 12 and 24. HIV RNA was generally undetectable in tissue. In contrast to other studies, levels of immune activation and CD4+ T cell depletion in the GALT persist despite maraviroc intensification. And in the small sample thus far, no statistically significant effect of intensification of ART with MVC on a variety of immunologic and virologic parameters in the GALT is seen.

Carolina Gutiérrez presented a difficult study for the group from Ramón y Cajal in Madrid. [11]

Again, stably suppressed patients intensified ART with maraviroc, this time for 12 weeks. In this study latently infected resting CD4 T cells were quantified using a limiting dilution co-culture assay. Residual viremia was measured by quantitative real-time RT-PCR assay (Single Copy Assay, SCA, threshold: 0.3 copies/mL), episomal 2-LTRs DNA in peripheral blood mononuclear cells was measured, and activation measured (HLA-DR and CD38 on CD4 and CD8 cells).

In nine patients studied so far, at baseline, the reservoir could be quantified in 6 patients (mean 2.04 infectious units per million (IUPM)). After 12 weeks of maraviroc intensification, all patients maintained viral load <50 copies/mL and a decrease in the latent reservoir was observed in 5 patients, while no decrease was found in one (mean 0.08 IUPM, P =0.048 compared to baseline). SCA increased in several patients, but not >50 copies/mL, and episomal 2-LTRs DNA were undetectable in the 9 patients at baseline and became detectable in 4 of them at week 12. HLA-DR and CD38 decrease 2.9% on CD4s (p=0.003) and not significantly on CD8s.

So unexpectedly, there was an apparent depletion of the resting cell reservoir, with a paradoxical increase in SCA, 2-LTR circles, but a decrease in activation. These findings appear discordant, and are hard to reconcile. However, most of the effects seen are of marginal magnitude, and so if possible longer-term study might help to clear up these confusing results.

Is there a summary?

Overall, intensification of durable, suppressive ART appears to have no effect on low-level plasma viremia. In some but not all studies modest effects can be measured such as small reductions of HIV RNA in tissue, or HIV DNA species in cells, or of cellular activation markers in tissue or circulating cells, and in one study resting CD4 cell infection frequency. It does appear that drug intensification is perturbing some equilibrium in the virus-infected patient, but the mechanism is not clear. I would propose that RAL and MVC are exerting a subtle, uncharacterized, non-virological effect resulting in the cellular changes measured. Repeated measures, and interventions might help clarify the mechanism of these phenomenon.

Tired T cells

Michael Lederman and his Bad Boys of Cleveland looked for correlates to understand why a large minority (ca. 25%) of patients who are successfully treated with ART are not able to enjoy an increase of CD4+ T cells into the normal range. [12]

The “Cleveland failure project,” perhaps an accidental reference to place called by some “the mistake on the Lake” (sorry, couldn’t resist), studied local patients who has been on ART for more than 2 years, and had viremia suppressed to <50 copies/mL for at least 2 years. Patients within incomplete immune restoration were those that had CD4 <350 cells/mm3 and they were compared to those with >500 cells/mm3 (ignoring those in the middle, 350-500, for clarity of analysis).

Lederman’s group studied 61 patients who met the failure criteria, identified 168 who met the criteria for success, and studied 20 of these lucky patients. In multivariate analysis, only nadir CD4 was independently associated with immune failure (p <0.001). “Failures” were more predominantly male (82% vs. 70% for immune restoration patients), and slightly older (ca. 4 years older on average). Of note CD8 cells were 2-fold higher in those with immune restoration. Of the subpopulations of CD4+ cells–naive cells, central memory cells, and effector memory cells–all were lower in the patients without full CD4 cell restoration. So failure was not specific to a CD4 cell subpopulation.

The activation markers CD38 and HLA-DR on both CD4 cells and CD8 cells tended to be somewhat higher in “failure” patients. Ki67, a marker of recently proliferating/cycling cells was higher in CD4, especially central and effector memory cells, but not in CD8 cells. This was one of the sentinel findings of the study, which Lederman entitled: “Immune failure after suppressive ART: high level CD4 and CD8 T cell activation but only memory CD4 cells are cycling.” This finding suggested that failure to fully recover the CD4 cell count might be related to a greater need to expand the CD4 cell pool to replace cells, and an inability to completely accomplish that task, despite apparently equivalent viral suppression. This finding is consistent with the observation that nadir CD4 was most strongly associated with immunological failure, and adds another reason to consider ART sooner rather than later. An additional useful tidbit was the suggestion that a lower CD8 cell count might portend poorer CD4 recovery, and if validated might also be used as a trigger to initiate ART earlier, or implement an immunotherapy strategy to boost CD4 cells (if we can find one that really works).

This report is an edited version of a longer report on the NATAP website.

Source: NATAP.org

http://www.natap.org/2010/CROI/croi_181.htm

References

Unless stated otherwise, all references are to the Programme and Abstracts of the 17th Conference on Retroviruses and Opportunistic Infections. 16-10 February 2010, San Francisco. All oral abstracts are available as webcasts.

1. Tony Fauci lecture. Pre-meeting plenary. Webcast: The HIV/AIDS Research Agenda. Tuesday 5.30pm.

2. Kearney M et al. The genetic diversity of HIV-1 in plasma persists despite suppression with ART. Oral abstract 98.

http://www.retroconference.org/2010/Abstracts/39122.htm

3. Yuki S et al. Differences in HIV burden throughout the gut of patients on suppressive ART: implications for HIV persistence. Oral abs 97.

http://www.retroconference.org/2010/Abstracts/38127.htm

4. Wiegand A el al. Raltegravir intensification does not reduce persistent HIV-1 viremia in treatment-experienced patients. Oral abs 280.

http://www.retroconference.org/2010/Abstracts/39474.htm

5. Hatano H et al. Raltegravir intensification in ARV-treated patients exhibiting a suboptimal CD4+ T cell response. Oral abstract 101LB.

http://www.retroconference.org/2010/Abstracts/39737.htm

6. Yukl S et a. Effect of raltegravir-containing intensification on HIV burden and T cell activation in the gut of HIV+ adults on suppressive ART. Poster abstract 279.

http://www.retroconference.org/2010/Abstracts/38158.htm

7. Buzon MJ et al. HIV-1 replication and immune dynamics are impacted by raltegravir intensification of HAART-suppressed Patients. Oral abstract 100LB.

http://www.retroconference.org/2010/Abstracts/39681.htm

8. de Laugerre C et al. No evolution of HIV-1 total DNA and 2-LTR circles after 48 weeks of raltegravir-containing therapy in patients with controlled viremia: a sub-study of the randomized EASIER-ANRS 138 trial. Poster abstract 281.

http://www.retroconference.org/2010/Abstracts/38779.htm

9. Wilkin T et al. Maraviroc intensification for suboptimal CD4+ cell response despite sustained virologic suppression: ACTG 5256. Poster abstract 285.

http://www.retroconference.org/2010/Abstracts/39637.htm

10. Evering T et al. The antiviral and immunological effects of intensification of suppressive ART with maraviroc, a CCR5 antagonist. Poster abstract 283.

http://www.retroconference.org/2010/Abstracts/37737.htm

11. Gutiérrez C et al. Effect of the intensification with a CCR5 antagonist on the decay of the HIV-1 latent reservoir and residual viremia. Poster abstract 284.

http://www.retroconference.org/2010/Abstracts/38572.htm

12. Lederman M et al. Immune failure after suppressive ART: high level CD4 and CD8 T cell activation but only memory CD4 cells are cycling. Oral abstract 47LB.

http://www.retroconference.org/2010/Abstracts/39722.htm

The 17th Conference on Retroviruses and Opportunistic Infections (CROI), one of the most important annual HIV meetings, was held this year from 16-19 February. As with previous meetings, much of the conference is published online including all abstracts and webcasts of oral presentations including poster discussions.

Making this scientific content available without login or subscription is itself a significant achievement. It is a model for broadening access to medical research to a degree that is currently unmatched by any other meeting.

The webcasts this year include oral presentations, poster discussions, the opening lectures and the pre-meeting set of training workshops for young investigators.

The conference website also includes a searchable abstract database.

We encourage readers to view these lectures directly.

http://www.retroconference.org/AbstractSearch/

http://www.retroconference.org/2010/data/files/webcast_2010.htm

Lectures are also available as audio downloads and podcasts which include slides as audiobooks.

Our first articles covering this meeting are:

• Treatment reduces infections by over 90%: a theme that is here to stay

• ACTG 5205: atazanavir/ritonavir vs efavirenz in treatment naïve patients

• Pipeline compounds and new approaches to treatment

• Clinical benefits of stopping smoking: CVD and CHD risk returns to that of ‘previous smoker’ in HIV-positive people within three years

• HIV increases the risk of lung cancer, independent of smoking status

• HIV-positive people in the HOPS cohort have 4-fold risk of fracture compared to general population in the US

• Vitamin D deficiencies in HIV management

• OCTANE 2: nevirapine and lopinavir/r are similar when used with tenofovir and FTC in treatment-naïve women

• HIV incidence and retesting in pregnancy

• Efavirenz use in pregnancy and birth outcomes

• Pregnancy outcomes in women using non-AZT HAART in Europe

• When should HAART be initiated in pregnancy to achieve an undetectable viral load?

• Pregnancy outcomes in infants exposed to maternal antiretrovirals in utero

• Maternal TB, HIV and pregnancy

More to follow next issue…

CROI was important this year because of the profile given to further studies supporting the role of treatment as prevention. Together they support the argument that universal treatment is perhaps the most powerful prevention tool we are likely to have for many years, perhaps with the potential to even eradicate the virus on a population level.

In a lecture prior to the main conference, Brian Williams from the South African Centre for Epidemiological Modelling and Analysis, Stellensbosch, detailed the modeling data for the direct and indirect impact of ARVs on prevention, [1] elaborating on the research paper published last year in the Lancet. [2]

At its most optimistic, this includes the potential for universal treatment to eliminate new infections in South Africa within 5-10 years on a cost neutral budget, at the same time saving millions of lives (and preventing millions of new infections). The science on which the model is based shows an impact on dramatically reducing infections that few can ignore.

The epidemiology for the model included low HIV infectivity (~0.001 per heterosexual encounter), 10-fold individual variability in infectivity, a slow epidemic doubling time (~1-3 years), a long period of potential infectiousness (5-15 years) and an average case reproduction number (~7 additional people infected per case): leading to a calculation showing that virtual eradication of HIV could be achieved if transmission could be reduced by 7-fold.

Viral load is commonly reduced by 10,000 times on treatment, and although infectivity reduces in smaller proportions (roughly in relation to the cube route of viral load), the net impact of treatment on infectivity was estimated to be a 96% reduction.

The impact on reducing TB and for continuous treatment after pregnancy were also included, and for interventions based only on PrEP alone or in combination with ARVs. For South Africa, the model was based on a conservative treatment programme, treating at a CD4 count of 200 cells/mm3, but similar costs and benefits were shown when starting universal treatment at 350, 500 or even at diagnosis. The initial outlay (an adjusted US $60 billion) was compensated by lower cost of hospitalisations and reduced new infections, and saved an additional 3 million lives over 40 years, at stable costs.

The discussion after the presentation stressed the need for pilot operational research on each aspect of a universal treatment model, including willingness to test, virological response rates with earlier treatment, the actual impact on transmission – and the need to develop new heath structures to allow such scale-up.

A first step in confirming treatment reduces HIV transmission in real world settings was shown in results from the Partners in Prevention HSV/HIV Transmission (PARTNERS) Study in over 3400 serodifferent heterosexual couples in seven southern African countries (Botswana, Kenya, Rwanda, South Africa, Tanzania, Uganda, and Zambia).  The HIV-positive partner was a man in 32% and a woman in 68% of couples. [3]

This study previously reported that HSV therapy with daily acyclovir failed to protect against HIV infections, explained by a massive increase in localised CD4 target cells, and persistence for up to two months after the healing of HSV lesions.

All HIV-positive partners entered the study with CD4 counts >250 cells/mm3 and were not on treatment. Over two years, approximately 10% of study participants required HIV treatment for their own care, and this allowed for the HIV transmission rates to be compared by use of ARV treatment. Intensive risk reduction support was supplied throughout the study, to minimise HIV risk for the HIV-negative partners.

People with more advanced HIV at baseline were more likely to start treatment; with higher baseline viral loads (mean 4.4 vs 3.9 log copies/mL, p<0.001), and lower CD4 counts (375 vs 540 cells/mm3, p<0.001). A higher proportion of men than women (12% vs 9%, p=0.01) strated treatment, at slightly lower median CD4 counts (192 vs 204 cells/mm3, p=0.05). People starting treatment were also older (mean 35.2 vs 32.7 years, p<0.001).

ART was initiated at CD4 counts <200 cells/mm3 in 52% patients, between 200 and 349 cells/mm3 in 33%, and >350 cells/mm3 in 15% (30% of this group were for prevention of mother to child transmission).

New HIV infections were detected in 151 of the HIV-negative partners, over 24 months of follow-up, with testing and prevention support provided every 3 months. Phylogenetic analysis suggested that slightly less than one third (43/151) of the infections were not from the relationship partner. Five cases were excluded from the transmission analysis due to uncertain use of ARVs.

This left an overall transmission rate in 103 remaining transmissions of 2.1%.

Of these, 102/103 were in the non-ARV group (102/4558 person years; rate 2.24 95%CI 1.82-2.72) compared to 1/103 from partners using ARV treatment (1/233 person years; rate 0.37 95%CI 0.09-2.04). This produced an unadjusted relative risk of 0.17 (p=0.037), which became even more significant when adjusting for time on study and CD4 count, showing a 92% reduction in risk: RR=0.08 (95%CI 0.002, 0.57, p=0.004).

The single transmission case occurred in someone whose partner started treatment 18 days before the 9 month assessment, when they were still HIV-negative (details on whether this was by HIV-antigen or PCR testing were not provided), but who seroconverted by the month 12 evaluations. Viral load was undetectable at month 12 in the HIV-positive partner.

Details on CD4 count in the HIV-positive partner showed transmissions at all CD4 levels, with a considerably higher risk when the partner had a count <200 cells/mm3 (rate = 8.79 vs 2.79 at 200-350 and 1.7 at 350-500).

This is likely to be an indirect marker of higher viral load relating to more advanced infections, but surprisingly, the presentation provided no further information on viral load levels of the source partner, other than showing that after a median of 7 months treatment (IQR 3-12months) the median viral load dropped to undetectable, indicating excellent responses.

Importantly, and perhaps showing the positive results from the behavioural interventions, the percentage of visits at which people reported unprotected sex dropped from 6.2% to 3.7% at the pre- and post-treatment visits, respectively, with no change in frequency of sex.

Two other studies at CROI, in a largely MSM population in San Francisco, supported the impact of ARVs to reduce transmission.

Moupali Das-Douglas and colleagues from the San Francisco Department of Public Health and the University of California presented results from a model that estimated values for average and total community viral load (CVL) from 2004-2008 and then compared these with the expected and actual number of new diagnoses over the same period. [4]

Average CVL was defined as the mean of the most recent viral load of all reported HIV-positive individuals in a particular population, divided by the number of reported HIV-positive individuals in the population. Total CVL was the sum of the most recent viral loads of all HIV-positive individuals in a particular population.

The context for this study was an effective ‘test and treat’ programme that from 2004 to 2008 increased the percentage of MSM testing within 12 months from 65% to 72% and within 6 months from 41% to 53%. The percentage of HIV-positive MSM unaware of their status dropped from 24% to 14.5% (comparable UK figures vary from 30-50%). By 2008, 90% of patients in care were on HAART, with 72% virologically suppressed (<75 copies/mL).

The decreases in mean CVL and reductions in actual diagnoses (from 798 in 2004 to 434 in 2008) were both statistically significant (p=0.005), as were the decreases in total CVL (p=0.019) and percentage of virologically suppressed patients (p=0.002). The presentation acknowledged that a limitation in these results is that cases may be diagnosed chronic rather than new infections, which was addressed in methodology for expected and actual incidence rates.

However, using a more conservative meta-regression analysis (different to the reported abstract), the 30% reduction in CVL and almost 40% reduction in incidence (rather than cases) was not significant (p=0.3) due to the degree of imprecision in the estimates.

While this makes it too early to link CVL with incidence, the reductions in newly diagnosed and reported cases, at the same time as increased testing, greater ARV coverage and greater virological suppression strongly support close following of subsequent data from this model.

In a related poster, Edwin Charlebois and colleagues modeled the impact of earlier treatment and broader test and treat programmes in San Francisco, suggesting that HIV prevalence could fall from the current 25% to around 10% by 2030 if the programme shifted to universal test and treat. [5]

As this issue of HTB went to press, a policy shift in San Francisco to offer HIV treatment to all newly diagnosed patients, regardless of CD4 count or viral load, was announced by public health officials. [6]

comment

The positive correlation between viral load and risk of transmission for every route, whether sexual, from shared injection equipment, during pregnancy, at birth and from breast milk, and from needle stick exposure to health workers, is now convincingly demonstrated.  For some of these transmission routes, antiretroviral treatment to reduce viral load is already widely used to reduce transmission (principally for mother to child transmission, PEP and PEPSE).

Treatment dramatically extends life, reduces morbidity and should now be additionally valued for reducing transmission. An estimated 70% of HIV-positive people globally in need of immediate treatment for their own care are still unable to access it.

References:

Unless stated otherwise, all references are to the Programme and Abstracts of the 17th Conference on Retroviruses and Opportunistic Infections. 16-10 February 2010, San Francisco. All oral abstracts are available as webcasts.

http://www.retroconference.org

1. Williams B and Dye C. Put your money where your model is: ART for the prevention and treatment of HIV/AIDS.  Webcast: Guiding the global response. Tuesday 2.30pm.

http://www.retroconference.org/2010/data/files/webcast_2010.htm

2. Granich RM et al. Universal voluntary HIV testing with immediate antiretroviral therapy as a strategy for elimination of HIV transmission: a mathematical model. The Lancet, Volume 373, Issue 9657, p48-57, 3 January 2009. doi:10.1016/S0140-6736(08)61697-9.

http://www.thelancet.com/journals/lancet/article/PIIS0140-6736(08)61697-9/abstract

3. Donnell D et al. ART and risk of heterosexual HIV-1 transmission in HIV-1 serodiscordant African couples: a multinational prospective study. 17th CROI 2010. Oral abstract 136.

http://www.retroconference.org/2010/Abstracts/39222.htm

Webcast: New Insights into Transmission and Acute Infection. Friday 9.30am.

http://www.retroconference.org/2010/data/files/webcast_2010.htm

4. Das-Douglas M et al. Decreases in community viral load are associated with a reduction in new HIV diagnoses in San Francisco. 17th CROI 2010. Oral abstract 33.

http://www.retroconference.org/2010/Abstracts/38232.htm

Webcast: Testing and Transmission. Wednesday 9.30am.

http://www.retroconference.org/2010/data/files/webcast_2010.htm

5. Charlebois E et al. Effect of Expanded ART Strategies on the MSM HIV Epidemic in San Francisco. 17th CROI 2010. Poster abstract 996.

http://www.retroconference.org/2010/Abstracts/39042.htm

6. San Francisco endorses starting HIV treatment immediately after diagnosis. (5 April 2010)

http://www.aidsmeds.com/articles/treatment_HIV_diagnosis_1667_18253.shtml

The few randomised clinical trials using currently licensed antiretrovirals worth highlighting from CROI partly stood out because there were fewer comparative studies that at previous CROI meetings. Of these, ACTG 5205, and its metabolic sub-study ACTG 5224s, generated most attention.

ACTG 5205

ACTG 5205 enrolled over 1850 treatment naïve patients from 2005-7 and followed them through to September 2009. The study was designed to compare efavirenz to atazanavir and tenofovir/FTC to abacavir/3TC by randomising equally to one of four groups. Patients were stratified by baseline viral load (above vs below 100,000 copies/mL). [1, 2]

Baseline demographics included 83% men/17% women; 40% white (non-Hispanic), 33% black, 23% Hispanic; median age 38 years median viral load ~50,000 copies/mL, and median CD4 230 cells/mL, Primary efficacy endpoints were time to confirmed virological failure (>1,000 copies/mL) at or after 16 weeks and before week 24 or viral load >200 copies/mL at week 24. Safety endpoints included time to first grade 3/4 event or laboratory abnormality at least one grade higher than baseline (excluding unconjugated hyperbilirubinaemia). Tolerability was assessed as time to change of treatment.

In February 2008, following a DSMB review, patients with baseline viral load >100,000 copies/mL who were using abacavir/3TC were unblinded and recommended to change to tenofovir/FTC due to significantly poorer virological responses. [3, 4]

Interpreting the final results now is further complicated because HLA-B*5701 testing was not available when the study started. Also, and perhaps more surprisingly, baseline resistance testing was performed in less than half the study group. In practice, this means that the most relevant results from the whole study relate to the comparisons between efavirenz vs atazanavir/r.

Using the primary virologic endpoint, there were no significant differences between atazanavir/r and efavirenz with either abacavir/3TC (HR 1.13, 95%CI 0.82–1.56) or tenofovir/FTC (HR 1.01, 95%CI 0.70, 1.46). The differences for the safety endpoint report benefits for atazanavir/r over efavirenz only with abacavir/3TC (HR 0.81, 95%CI 0.66–1.0; p=0.05), probably driven by a caution over management of rash and a potential hypersensitivity reaction when NNRTIs are prescribed with abacavir. This was seen even more in the tolerability analysis (HR 0.69, 95%CI 0.55, 0.86; p=0.0008).

Cardiovascular and renal events, non-AIDS malignancies and bone fractures were broadly similar in each group.

Again, as seen in other PI vs NNRTI studies, patients with virological failure were significantly more likely to develop resistance on the NNRTI compared to the PI regimen (approximately 60% vs 20% of virological failures included >1 major mutation in the efavirenz vs atazanavir/r group respectively).

The only signficant differences in CD4 responses were seen when atazanvir/r group was compared to efavirenz, but only when tenofovir/FTC was used as the nucleoside backbone (+252 vs +221 cells/mm3 at 96 weeks, p=0.002).

Lipid differences were more complicated, and while statistically significant for some values, may or may not be of clinical relevance.

In an on-treatment analysis at week 48, efavirenz was consistently associated with significantly greater increases in total cholesterol, LDL and HDL regardless of nucleosides (all comparisons p<0.001, except LDL with TDF/FTC, p=0.002). Increases were also consistently greater with abacavir/3TC compared to tenofovir/FTC. There were no significant differences for triglycerides although there was a trend for greater increases with atazanavir/r compared to efavirenz, when used with tenofovir/FTC (p=0.07). Despite this, there were no significant differences in total cholesterol:HDL ratio in any comparisons.

Finally, creatinine clearance dropped by approximately -3.0 mL/min at week 96 (as-treated analysis) when atazanavir/r was used with tenfovir/FTC compared to slightly higher increases in the other three groups (p<0.001). These differences were described as modest and <5% of patients in any arm experienced changes of greater than 25% decline.

ACTG 5224s

The metabolic substudy ACTG 5224s provided data on bone mineral density (BMD) and limb fat changes in 269 patients in ACTG 5202 (approximately 65 from each of the four comparative regimens). [5, 6]

Exclusion criteria for the substudy included diabetes or other complications including use of medication related to bone or body composition. DEXA evaluations (whole body and bone) were taken at baseline and at 24, 48 and 96 weeks, then annually. CT abdominal scans were taken at baseline and at week 96.

When no interaction was seen between either the RTI component or third drug components, factorial analyses were performed comparing pooled results for each dual RTI, and for atazanavir/r to efavirenz.

Primary endpoints included percentage changes in hip and lumber spine between the two RTI components, and changes of >10% loss of limb fat. Secondary analysis included fracture rates and the same bone and fat changes in the PI vs NNRTI groups.

Baseline demographics broadly reflected the main study and were balanced between groups. Of note, baseline rates of osteopenia (T-score <1.0) were 35% at lumbar spine and 23% at the hip.

Mean values for BMD at lumbar spine dropped in all groups over the first year of treatment and then recovered by about 50% over the subsequent year. These declines were more significant in the tenofovir/FTC compared to abacavir/3TC (approximately -3.5%% vs -1.5% at week 96, p=0.004) group and in patients using atazanavir/r compared to efavirenz (-3.2% vs -1.7, p=0.035).

Tenofovir/FTC was associated with a greater drop in hip BMD at 96 weeks compared to abacavir/3TC (-4.0% vs -2.6%, p=0.025) with no difference between atazanavir/r and efavirenz (p=0.59, each approx -3.0%). Early declines in hip BMD did not appear to reverse over time.

Fracture rates were similar in all groups, with an incidence of 1.7 per 100 patient years, all of which were reported as traumatic (ie expected in general life). No difference by regimen was seen in the main study (where 12% of fractures were without trauma).

Changes in fat distribution was complicated by the study decision to select a relatively marginal 10% cut-off for fat loss as the endpoint. No differences were seen between arms using this criteria (approximately -16%), with a post-hoc analysis using >20% reported in <5% patients with no clear RTI or third drug association.

Absolute mean values increased in both RTI arms (approximately +1 kg gain, no statistical difference) but this was higher in the atazanavir/r vs efavirenz groups (approximately +2 kg vs +1 kg;  +30% vs +15%, both p=0.008).

Trunk fat increases were similar in each RTI group, but atazanavir/r had greater increases at 96 weeks compared to efavirenz (approximately +2.4 kg vs +1.2 kg, p=0.023).

comment

The clearest outcome from these complicated results is likely to be a stronger recommendation for atazanavir/ritonavir as a clinical option in for first-line therapy.

Absolute differences in side effects, tolerability and metabolic differences are more complicated to interpret in clinical terms, even when they are statistically significant, but would be a factor to consider in individual patients at higher risk.

The reductions in bone mineral density in all groups are concerning, especially given the high percentage of patients with low levels at baseline. While fracture rates in this study were low, other studies at CROI suggested that the concern that ageing will uncover reduced BMD as a greater complication in HIV-positive people compared to the general population, may, unfortunately, be well founded.

Fat changes are difficult to interpret given the choice of endpoint for fat loss, although ~5% patients lost >20% fat across all arms. The significant increases in trunk fat, largely interpreted as a return to health effect, were based on DEXA results. The analysis of CT results, not included in the CROI presentation, is needed to determine whether this is an accumulation of visceral or subcutaneous fat.

References

Unless stated otherwise, all references are to the Programme and Abstracts of the 17th Conference on Retroviruses and Opportunistic Infections, 16-19 February 2010, San Francisco.

All oral abstracts are available as webcasts.

http://www.retroconference.org

1. Daar E et al. ACTG 5202: Final results of ABC/3TC or TDF/FTC with either EFV or ATV/r in treatment-naive HIV-infected patients. 17th CROI 2010. Oral abstract 59LB.

http://www.retroconference.org/2010/Abstracts/39789.htm

2. Webcast: Advances in ART. Wednesday 9.30am.

http://www.retroconference.org/2010/data/files/webcast_2010.htm

3. US study changes use of abacavir/3TC in naïve patients with viral load >100,000 copies/mL based on DSMB recommendation. HIV Treatment Bulletin, April 2008.

http://i-base.info/htb/1811

4. Sax P et al. Abacavir-lamivudine versus tenofovir-emtricitabine for initial HIV-1 therapy. N Engl J Med. 2009;361. DOI: 10.1056/NEJMoa0906768.

http://www.ncbi.nlm.nih.gov/pubmed/19952143

5. McComsey G et al. Bone and limb fat outcomes of ACTG A5224s, a substudy of ACTG A5202: a prospective, randomized, partially blinded Phase III trial of ABC/3TC or TDF/FTC with EFV or ATV/r for initial treatment of HIV-1 infection. 17th CROI 2010. Oral abstract 106LB.

http://www.retroconference.org/2010/Abstracts/39788.htm

6. Webcast: Complications of HIV and ART. Thursday 9.30am.

http://www.retroconference.org/2010/data/files/webcast_2010.htm

There were fewer presentations at this years meeting on either new drugs or comparative studies between existing drugs. While the missing studies were very noticeable, this is probably more due to the recent approval of several new drugs over the last two years.

It may be significant though that most of the notable studies were nearly all included in one oral abstract session. [1]

QUAD, elvitegravir and cobicistat

New clinical data was presented on the integrase inhibitor elvitegravir, in combination with a new pharmacokinetic booster from Gilead called cobicistat (previously GS-9350), both coformulated with tenofovir/FTC in a four-in-one tablet called Quad. [2]

When Quad was compared to Atripla (efavirenz + tenofovir + FTC), over 80% of patients in each group had undetectable viral load (less than 50 copies/mL) after 24 weeks. However, mean  baseline viral load was <40,000 copies/mL, and it was only >100,000 copies/mL in 25% of patients. In this Phase 2 study, patients in the Quad group (n=48) became undetectable more quickly than those on Atripla (n=23), as was seen with raltegravir. For example, after 8 weeks, about 80% people were undetectable with Quad compared to about 50% with Atripla.

While Quad was better tolerated in terms of not having efavirenz-related side effects, a caution due to the impact of cobicistat on reducing estimated glomerular filtration rate (eGFR) – but not actual GFR – suggests that management of renal toxicity may have to be handled differently.

Results from a second Phase 2 study were presented in the same oral presentation, this time comparing the new booster (n=50) to ritonavir (n=29), each in combination with atazanavir, tenofovir and FTC. [2]

No differences were seen in efficacy or tolerability between the two boosters. Unlike ritonavir, cobicistat has no antiretroviral activity.

In summary, results were sufficiently encouraging for both QUAD and cobicistat to be taken into larger Phase 3 studies.

Compounds in earlier development

A dose-finding Phase 1 study of a CCR5-inhibitor in development with Tobira Pharmaceuticals under the compound name TBR-652. The compound has a plasma half-life of 35-40 hours allowing once-daily dosing and although metabolised by CYP and non-CYP pathways is neither and inducer or inhibitor of CYP P450. [3]

These first results in 54 HIV-positive patients produced median viral load reductions of 1.7 log with the 50, 75 and 150mg doses after 10 days monotherapy. Although baseline viral load was lower in the 150mg group (median 4.0 logs, compared to 4.5 and 4.6 logs in the 50mg and 75mg groups), all patients using the 75mg dose had >1.0 log reductions. Patients were treatment-experienced (off treatment for at least 6 weeks), CCR5-naïve and CCR5-postive. No dose-related or serious side effects were reported, though the study was only in about 50 people.

Side effects were mild (none reported at the 75mg dose) and included nausea, diarrhoea, headache and fatigue in greater frequency at the 100 and 150mg – although many of these were reported as being associated with one patient with a concomitant infection.

Very little new information was available for the new integrase inhibitor in development with Shionogi and GSK called S/GSK1349572. [4] Although included in the oral session, this was more a product overview, adding no new in vivo data to that presented at the IAS meeting in Cape Town last year. [5]

Results from a pooled analysis of 721 treatment experienced patients in the unfortunately named Victor-E 3 and 4 Phase studies, presented by Joe Gathe, disappointingly found to too little difference compared to placebo for the troubled CCR5-inhibitor vicriviroc to continue to be taken forward for further development. In a modified ITT analysis the percentage of patients with undetectable viral load (<50 copies/mL) at 48 weeks was 64% and 61% in the vicriviroc and placebo groups respectively (p=0.6). [6]

The presentation suggested this was because of more effective background drugs were available for patients to construct optimum background therapy (approximately 65% had >3 active drugs), for the third agent to show significant advantages. A prespecified sub analysis showed that 70% of people randomised to the vicriviroc arms who had <2 active drugs achieved <50 copies/mL compared to 55% of the placebo group, and an indication that this was significant. As the vicriviroc group had fewer active drugs at baseline, this potentially obscured a difference in activity between the two arms.

While safety was apparently similar, during the questions, we learned that there were 7 vs 0 deaths in the vicriviroc and placebo arms respectively, not apparently significant after adjusting for time on treatment.

Despite the early promise, it looks likely that the development of this compound will now be put on hold. [6]

Preliminary studies looking at a handful of other targets and approaches, including attempts to target latently infected cells were presented as posters.

Frauke Christ and colleagues from University of Leuven, Belgium, detailed potential compounds from a new class of integrase inhibitor, called LEDGINS, that would not bind at the active site, and therefore not be cross-resistance to raltegravir or elvitegravir. These potential molecules, 2-(quinolin-3-yl)acetic acid derivatives, were designed by rational drug design, and identified after screening 200,000 molecules. [7]

Stephen Mason presented preclinical results on two early compounds that could interfere with the assembly and stability of the capsid core, that are in development at Boehringer Ingleheim. These compounds interrupt the process for assembling new virus and were shown to have activity against resistant HIV from other classes. [8]

Many presentations reiterated that eradication with current drugs is not possible, due to the inability to recognise latently infected resting cells. Even after many years of maximally suppressive therapy, it is well established that viral load rapidly rebounds to pretreatment levels, potentially within weeks of discontinuing treatment.

At least five new types of treatment are the focus of research on how to target latently infected cells. These include cellular restriction factors – human proteins that reduce HIV replication and that can help or block infections – such as tetherin, a protein that blocks HIV release, APOBEC3, an immunity gene that has anti-HIV activity, and TRIM5-alpha, a protein that in some monkeys protects against HIV infection, and that gene therapy could perhaps be modified to adapt the related human protein. Zinc finger inhibitors that can knock out CCR5 were included in other presentations, although this potential target that has been on the outer radar of investigative treatment for at least 15 years.

References

Unless stated otherwise, all references are to the Programme and Abstracts of the 17th Conference on Retroviruses and Opportunistic Infections, 16-19 February 2010, San Francisco.

1. Webcast: Advances in ART. Wednesday 9.30am.

http://www.retroconference.org/2010/data/files/webcast_2010.htm

2. Cohen C et al. Single-tablet, fixed-dose regimen of elvitegravir/emtricitabine/tenofovir disoproxil fumarate/GS-9350 achieves a high rate of virologic suppression and GS-9350 is an effective booster. 17th CROI 2010. Oral abstract 58LB.

http://www.retroconference.org/2010/Abstracts/39864.htm

3. Palleja S et al. Safety and efficacy of TBR 652, a CCR5 antagonist, in HIV-1-infected, ART-experienced, CCR5 antagonist-naïve patients. 17th CROI 2010. Oral abstract 53.

http://www.retroconference.org/2010/Abstracts/37579.htm

4. Johns B et al. The discovery of S/GSK1349572: a once-daily next generation integrase inhibitor with a superior resistance profile. 17th CROI 2010. Oral abstract 55.

http://www.retroconference.org/2010/Abstracts/37960.htm

5. First results of new integrase compound: GSK1349572. HTB October 2009.

http://i-base.info/htb/5976

6. Gathe J et al. Phase 3 trials of vicriviroc in treatment-experienced subjects demonstrate safety but not significantly superior efficacy over potent background regimens alone. 17th CROI 2010. Oral abstract 54LB.

http://www.retroconference.org/2010/Abstracts/39832.htm

7. Christ F et al. First-in-class inhibitors of LEDGF/p75-integrase interaction and HIV replication. 17th CROI 2010. Oral abstract 49.

http://www.retroconference.org/2010/Abstracts/37630.htm

8. Titolo S et al. Discovery of potent HIV-1 capsid assembly inhibitors. 17th CROI 2010. Oral abstract 50.

http://www.retroconference.org/2010/Abstracts/38238.htm

An analysis from the D:A:D study, presented as an oral session, reported that HIV-positive people who stop smoking can expert similar direct health benefits to HIV-negative people.

Kathy Petoumenos from the University of New South Wales, Sydney, looked at rates of cardiovascular disease before and after stopping smoking in over 27,500 HIV-positive patients from Europe, the US and Australia, who had smoking status recorded in the prospective D:A:D cohort study.

The group looked at four endpoints: fatal and non-fatal myocardial infarction (MI), a broader definition of coronary heart disease (CHD), cardiovascular disease (CVD) combining CHD and stroke, and all cause mortality. Event rates were calculated for never smokers (n=8,920), ex-smokers at D:A:D study entry (n=6,265), current smokers (n=11,951), and smokers who stopped during D:A:D follow-up (n=8,197).

Current smokers were more likely to be male (77%), white (70%), infected through IV drug use (32%) and HCV-positive (34%), but CD4, viral load, BP, lipids and ARV-exposure were broadly similar between groups.

Incidence rate ratios (IRR) were determined adjusting for age, sex, cohort, calendar year, antiretroviral treatment, family history of CVD, diabetes (men and women), and time updated lipids and blood pressure assessments. Mortality endpoint also adjusted for HCV, HBV, mode of HIV exposure, ethnicity and incidence of CVD during follow-up.

Up to February 2008, there were 432 (MI), 600 (CHD), 746 (CVD) and 1902 (mortality events) endpoints. Crude event rates were 2.85, 3.96, 4.94, and 12.45 per 1000 person years respectively.

With never-smoked as the reference, increased risks rates were 1.73 and 3.40 for previous- and current-smokers respectively. Rate ratios for patients who had stopped smoking for <1, 1-2, 2-3 and >3 years follow-up since quitting, were 3.73, 3.00, 2.62 and 2.07 respectively, compared to never-smokers. This showed significant reductions within a year of stopping that continued to reduce over subsequent years. A similar pattern was seen for CHD and CVD, and although these were not significant at all timepoints, this is likely to be related to the lower number of events in some groups and the lower number of people who stopped smoking more than two years ago. The protective trend here is clear and important (see Table 1).

Although current smokers were at 28% higher risk of mortality, with no difference between never- and former-smokers, no clear reductions were seen during follow-up since stopping, with all confidence intervals crossing 1.0, even in a sub-group at higher risk of CVD-related mortality (in patients older than 50 years).

Table 1: Incidence rate ratios by baseline smoking status and time since quitting

* Non significant (CI crossed 1.0)

An explanation for the higher rates seen in the most recent (< 1 year) quitters was explained by the likelihood that a medical incident could have been the prompt needed to stop smoking. This group would therefore be at higher risk compared to current smokers (who would have been symptomatic). This was supported by the cause of mortality being more likely to be HIV/AIDS in the never smoked group with higher rates of non-AIDS malignancies seen in the previous and stopped groups.

The study has limitations in the amount and type of data that were collected on smoking (e.g. no start/stop dates or pack-year data). However, the significant reductions on CHD with each year after stopping smoking should support cessation programme for HIV-positive people, a greater percentage of whom smoke than the general population.

comment

This is the first time that the clinical benefits of stopping smoking has been reported in HIV-positive people and these findings should not be taken for granted.

Each year, HIV-positive people are advised on the importance of modification of lifestyle for ‘healthy options’ related to the complicated etiology of cardiovascular health and any study that can show tangible benefits is important.

This is particularly important given the higher rates of lung cancers reported in other studies. Keith Sigel and colleagues reported that HIV is an independent risk factor for lung cancer after adjusting for smoking (IRR 1.80; 95%CI 1.28 2.15). [2]

Edgar Simard from the US National Cancer Institute, reported a 3-fold observed incidence of lung cancer in HIV-positive patients within 3-5 years of an AIDS diagnosis compared to the general population (and increasing cumulative incidence). [3]

Meredith Shiels and colleagues reported that lung cancer was one of the cancers that was being diagnosed at an earlier age in HIV-positive compared to HIV-negative people, and that this 3-4 year difference was statistically significant after adjustment for multiple comparisons (p<0.001). [4]

References

Unless stated otherwise, all references are to the Programme and Abstracts of the 17th Conference on Retroviruses and Opportunistic Infections. 16-10 February 2010, San Francisco. All oral abstracts are available as webcasts.

http://www.retroconference.org

1. Petoumenos K et al. Rates of cardiovascular disease following smoking cessation in patients with HIV infection: results from the D:A:D study. 17th CROI, 2010. Oral abstract 124.

http://www.retroconference.org/2010/Abstracts/38289.htm

2. Sigel K et al. HIV infection is an independent risk factor for lung cancer. 17th CROI, 2010. Oral Abstract 30.

http://www.retroconference.org/2010/Abstracts/38365.htm

3. Simard E et al. Cancer incidence and cancer-attributable mortality among persons with AIDS in the US. 17th CROI, 2010. Oral abstract 27.

http://www.retroconference.org/2010/Abstracts/38173.htm

4. Shiels M et al. Do people with AIDS develop cancer at younger ages than the general population? 17th CROI, 2010. Poster 757.

http://www.retroconference.org/2010/Abstracts/37914.htm

Keith Sigel and colleagues presented an analysis from the US Veterans Ageing Cohort Study Virtual Cohort (VC) on the relationship between HIV and lung cancer. [1]

The advantages of this database included size, smoking status data from a related health survey and a matched HIV-negative control group, although this was an almost exclusively (98%) male study. Median age was 47 years and ethnicity was approximately 40% white, 40% black. 10% Hispanic and 10% other. Approximately 30% were current smokers, 15% recently quit (< 1 year), 25-50% distantly quit (> 1 year) and 20% of HIV-positive compared to 25% of HIV-negative had never smoked.

The analysis compared over 3,700 HIV-positive and nearly 10,000 HIV-negative patients (contributing 28,500 and 76,800 person-years of follow-up respectively).

Lung cancer was defined using International Classification of Diseases (ICD-9) codes and Incidence Rate Ratios (IRR) were adjusted for age, race, smoking exposure, and Chronic Obstructive Pulmonary Disease (COPD).

The overall incidence of lung cancer per 100 person years was 0.26 compared to 0.16 in the HIV-positive vs HIV-negative groups (unadjusted IRR 1.5, 95%CI 1.2–2.0). Results from the adjusted analysis are detailed in Table 1.

Table 1: Adjusted IRR for lung cancer multivariate model including all covariates

* Reference = white race; ** Reference = never smoked.

The authors concluded that the incidence of lung cancer was significantly increased in HIV-positive men in their group, even after adjusting for smoking exposure.

comment

This study reported slightly lower rates of increased risk of lung cancers in HIV-positive individuals compared to rates that were 2- to 6-fold higher in earlier studies, that also adjusted for smoking status. [2, 3, 4]

While the approximate 2-fold increased risk associated with HIV was significant and is important, the presenter emphasised the 10-fold higher risk for current smokers (that was halved to around 5-fold for former smokers who had quit more than one year earlier).

References

Unless stated otherwise, all references are to the Programme and Abstracts of the 17th Conference on Retroviruses and Opportunistic Infections. 16-10 February 2010, San Francisco. All oral abstracts are available as webcasts.

http://www.retroconference.org

1. Sigel K et al. HIV infection is an independent risk factor for lung cancer. 17th CROI, 2010. Oral Abstract 30.

http://www.retroconference.org/2010/Abstracts/38365.htm

2. Cadranel J et al. Lung cancer in HIV infected patients: facts, questions and challenges. Thorax 2006; 61:1000-1008.

http://thorax.bmj.com/content/61/11/1000.abstract

3. Engels EA et al. Elevated incidence of lung cancer among HIV-infected individuals. J Clin Oncol 2006; 24 (9); 1383-1388. (March 2006).

http://jco.ascopubs.org/cgi/content/abstract/24/9/1383

4. Kirk GD et al. HIV infection is associated with an increased risk for lung cancer, independent of smoking. Clin Inf Dis 2007; 45:103-110.

http://www.journals.uchicago.edu/doi/abs/10.1086/518606

Over the last ten years HTB has reported numerous studies of lower bone mineral density and higher rates of osteopenia and osteoporosis in HIV-positive people compared to rates in age- and gender-matched general population.

While some research groups cautioned that their findings might not translate into higher fracture rates, most others suggested that ageing was likely to compound this risk and that it would be only a matter of time before the additional impact of HIV might be seen.

Two studies at CROI unfortunately suggest that these concerns are likely to be real.

Christine Dao from the US CDC in Atlanta and colleagues presented an analysis of fracture rates from 1994-2008 in over 8,400 HIV-positive patients followed in the HIV Outpatients (HOPS) Cohort and compared this to rates from non-HIV US inpatient (NHDS) and outpatient (NHAMCS) surveys that were weighted to make inferences to the US general population.

Only first fractures were included from HOPS and adjusted Hazard Ratios (AHR) were calculated controlling for age and gender. As fracture data were not comprehensively collected in HOPS prior to 2000, the presentation focused on fractures from around 5800 patients seen at least annually over the last eight years.

Baseline characteristics at first visit included: 79% male; 52% non-Hispanic white, 38% non-Hispanic Black; median (IQR) age 40 years (34-46), median BMI 24.4 (22.3-27.4); median time since diagnosis 5.3 years (1.3-9.9). Three-quarters of patients were treatment-experienced with median viral load (for the cohort) of 1,300 (<400-35,560) copies/mL.

Approximately 4% patients (236/5826) experienced a fracture at median age 45 years (38-51), roughly in proportion to baseline characteristic of race and gender, although only 51% of fractures were in treatment-experienced patients.

Gender-adjusted rates were restricted to patients aged 25-54, representing most HIV-positive individuals and showed not only an increase in fracture rates over time from about 55 to 85/10,000 PY, p=0.01 (compared to stable rates at around 30/10,000 PY in general population outpatient data). The rate in HIV-positive people was stable from 2002-2008 (and was approximately 4-fold higher).

Fractures at fragility sites (wrist, vertebra, femoral head) occurred at higher rate in both HIV-positive men and women compared to the general population, and are detailed in Table 1.

Factors independently associated with increased risk of fracture (adjusted HR: 95%CI) included: age >47 years (1.6; 1.0–2.5, p<0.05); nadir CD4 <200 cells/mm3 (1.6; 1.1–2.3, p=0.04); HCV coinfection (1.6; 1.1–2.3, p=0.01); diabetes (1.6; 1.0–2.6, p<0.05); and history of substance use (1.5; 1.0–2.3, p<0.05).

Limitations of the study included the use of different data collection systems for the HIV-positive and general population groups, no data linking bone mineral density to fracture risk, and whether this increase was due to an increase in events or a potential improved reporting.

Table 1: Percentage of fractures by anatomic site in adults 25-54 years old (HOPS 2000-2008)

Importantly, they also stressed that the actual event rate remained low, even though the relative rate was significantly higher.

Nevertheless, the researchers concluded that HOPS patients experienced higher rates of fracture compared to the general US population, that this rate increased over time and included a higher percentage of fragility fractures; and that in addition to known risk factors, low CD4 nadir was also associated with increased fracture risk.

Julie Womack and colleagues from the Veterans Ageing Cohort Study (VACS) presented results from men in the largely male VA cohort, focusing on the prevalence and incidence of fragility fractures (ie associated with minimal or no trauma, and with low bone mineral density). [2]

The VACS is a prospective observational cohort of about 40,000 HIV-positive veterans matched 1:2 by age, sex and site to around 80,000 HIV-negative controls. This analysis only included first fracture. Wrist fractures and compound fractures were excluded because of the higher likelihood of being related to trauma.

Multivariable models were adjusted for HIV status, race, enrollment date, age, coinfection, BMI and corticosteroid use, with additional adjustment for baseline CD4 and ARV use in HIV-positive patients.

During a median follow-up of 8 years (range 4-11), 952 fractures (644 hip and 308 vertebral) fractures were recorded, with an unadjusted incidence of 16 vs 11/10,000 PYFU in the HIV-positive vs HIV-negative groups. Fractures occurred at a mean age of 55 years (SD+11).

Prevalence results showed that across all ages only hip fractures occurred at a significantly higher rate in the HIV-positive vs HIV-negative groups (p<0.0001), with a difference developing and widening from age 40 onwards. Although vertebra fractures were generally similar in both groups, the rate in HIV-positive men increased significantly in men over 70 years who were HIV-positive.

After adjustment for cofactors (AHR; 95%CI), including Caucasian race (1.79; 1.57–2.03), BMI <19 (2.50; 1.54–4.05), alcohol use (H1.79; 1.47–2.18), pulmonary disease (1.38; 1.10–1.73), cerebrovascular disease (2.16; 1.54–3.02), and peripheral vascular disease (1.64; 1.10–2.44), the HIV effect was reduced, though still significant (1.38; 1.18–1.60). Similar ratios applied for the full model and HIV-positive only model.

The presentation also discussed management and this was picked up in the question session afterwards. Prevention is stressed for all patients. Clinical assessment for fracture risk was recommended for patients aged 40-50 and DEXA indicated when HIV is not the only risk factor.

Several members of the audience commented that they would encourage broader use of DEXA scans, especially given the high rates of other risk factors, including higher rates of smoking, alcohol use and low testosterone.

Although ARV use was not found to be significant in this study, another question from the audience suggested that this was unlikely to be a reliable conclusion, as the study defined exposure by baseline use of d4T, tenofovir, PIs or NNRTIs, rather than looking at cumulative exposure more commonly adopted in most studies.

Finally, a third presentation in the same oral session reported fracture incidence in a retrospective analysis in about 2400 women (approxiamtely 1700 HIV-positive, 700 HIV-negative) in the Women’s Interagency HIV Study (WIHS). Of note, this study also collected data on smoking, opiate/cocaine use and vitamin D/calcium supplementation.

Fractures occurred in 148 (9%) HIV-positive women vs 47 (7%) HIV-negative women producing incidence rates of 1.79 vs 1.41/100 PY, respectively (p=0.13 NS). Analysis by fracture site also showed no significant difference in rates by HIV status. In the multivariate analysis, HIV status remained non-significant, with only age, race (being Caucasian), HCV coinfection and serum creatinine only showing positive relationship to increased fracture rate. The only determinants of time to fracture in HIV-positive women were age (per 10 years older HR 1.2; 95%CI 1.0–1.5, p=0.047) and previous AIDS defining illness (HR 1.9; 95%CI 1.3–2.7, p=0.0008), but not CD4 count or ARV use.

Although no impact of HIV was seen over five years of follow-up the limitations of this study was that this was broadly a pre-menopausal patient group and in a modest sample size. Also, approximately 50% women had high BMI which is associated with protecting bone density and strength.

The conclusion included recognition that fracture risk could increase in HIV-positive post-menopausal women, given that oestrogen has a protective effect and other studies have already highlighted the lower levels of bone mineral density in HIV-positive women.

References

Unless stated otherwise, all references are to the Programme and Abstracts of the 17th Conference on Retroviruses and Opportunistic Infections. 16-10 February 2010, San Francisco. All oral abstracts are available as webcasts.

http://www.retroconference.org

1.  Dao C et al. Higher and increasing rates of fracture among HIV-infected persons in the HIV Outpatient Study compared to the general US population, 1994 to 2008. 17th CROI 2010. Oral abstract 128.

http://www.retroconference.org/2010/Abstracts/37582.htm

2. Womack J et al. HIV-infection and fragility fracture risk among male veterans. 17th CROI 2010. Oral abstract 129.

http://www.retroconference.org/2010/Abstracts/39138.htm

3. Yin M et al. Fracture rates are not increased in younger HIV+women. 17th CROI 2010. Oral abstract 130.

http://www.retroconference.org/2010/Abstracts/38338.htm

HTB has run several articles on vitamin D deficiencies in previous issues in relation to bone problems, tenofovir and efavirenz. There is increasing concern and research about vitamin D deficiency in people with HIV, especially with regard to African immigrants and people of African descent living in the cold climates of North America and Europe. There were several posters on this topic at CROI 2010 and so a themed discussion on it was held, chaired by discussants Peter Reiss of the University of Amsterdam and Michael Yin of Columbia University. Reiss started the session by giving a clear explanation of the basic science of vitamin D. [1-3]

Background

Vitamin D is a group of fat soluble prohormones that mainly originate in the skin where ultraviolet radiation interacts with 7-dehydrocholesterol to form pre-vitamin D3 and then vitamin D3. This process is harder in people with darker skins. Some vitamin D3 is also consumed from diet and supplements. The main purpose of vitamin D is to increase the flow of calcium in the bloodstream.

Vitamin D3 is hydroxylated by the enzyme 25-hydroxylase into hydroxylated vitamin D, 25(OH)D, in the liver.  An alternative pathway to hydroxylated vitamin D is via vitamin D2 acquired from diet, but this is considered a less important source.

The hydroxylated vitamin D, 25(OH)D is then further hydroxylated in the kidneys to one-alpha-hydroxylated-vitamin D (1α-25(OH)2D) which is the active metabolite. The enzymes involved in this process belong to the cytochrome p450 family, which is a catalyst for some antiretrovirals. There is also speculation that HIV itself affects the production of vitamin D (discussed further below).

Even though 1α-25(OH)2D is the active metabolite, for diagnostic purposes the amount of its precursor, 25(OH)D is  measured. This is because if there is a deficiency in 25(OH)D, an auto-regulatory mechanism upregulates the manufacture of 1α-25(OH)2D. So a person can have sufficient amount of the active metabolite, but still have a deficiency of vitamin D.

Clinical consequences of vitamin D deficiency

Widely accepted criteria for clinically sufficient, insufficient and deficient levels of vitamin D are given in Table 1. However, as Reiss pointed out, by this definition, 40 to 100% of elderly people are deficient in vitamin D and the criteria do not account for ethnic differences. Moreover optimum levels of vitamin D for skeletal and extra-skeletal health have not been established neither in the general population nor for specific ethnic groups.  As is clear from the presentations described in Table 1 below, these criteria are not standardised.

Julian Falutz of McGill University has compiled a table of studies examining vitamin D levels in people with HIV (Table 2). They cover a wide range of countries, seasons, CD4 count ranges and levels of ARV uptake, giving a diverse range of proportions of people categorised as sufficient, insufficient or deficient.

Table 1: Criteria for clinical definitions of 25(OH)D3 in blood (Reiss [3])

Table 2: Vitamin D studies in people with HIV (Falutz)

The role of HIV and its treatment in vitamin D regulation is speculative and complex. HIV might affect dietary intake in sick people which in turn might affect levels of vitamin D. HIV might also affect the 1-alpha hydroxylation step and thereby inhibit synthesis of the active metabolite. Vitamin D might also be used by maturing and proliferating T-cells. With their increased production during HIV infection, there might be greater utilisation of vitamin D. The utilisation of cytochrome p450 enzymes by NNRTIs and protease inhibitors might also affect levels of vitamin D.  The hydroxylation step in the kidney takes place in the proximal tubular cells, which are also affected by tenofovir, and this might impact on vitamin D levels. On the other hand ritonavir inhibits 1α-hydroxylase and consequently this might lead to an accumulation of unconverted 25(OH)D in the kidneys.

Vitamin D receptors are found on nearly all cells and deficiency of it is associated with many diseases such as osteomalacia (softening of bones), inflammatory conditions, hypertension, cardiovascular disease, insulin resistance, renal disease, prostate and colon cancer, greater risk of bacterial infection, cognitive dysfunction and frailty.

The SUN study

Christine Dao of the CDC presented results of the SUN study. This study assessed levels of vitamin D (measured by 25(OH)D, as with all other studies presented here) from 2004 to 2006 in the United States in 672 adults with HIV. Insufficiency was defined as less than 30ng/mL. The study found 72% of participants were vitamin D insufficient. Black race, Hispanic ethnicity, lower ultraviolet exposure, hypertension, lack of exercise and efavirenz exposure were independently associated with insufficiency. On the other hand renal insufficiency (GFR<90) and ritonavir exposure were independently associated with lower odds of insufficiency. In question time, Dao stated that 9% of participants were deficient, defined in this study as a 25(OH)D less than 10ng/mL (which is different from the definition of deficiency given above). [4]

Italian cohort

Antonella d’ Arminio Monforte from the University of Milan presented the results of an observational cohort with retrospective analysis in vitamin D in stored plasma samples of 852 patients contributing 1,498 measurements. Of these, 262 measurements were taken before and 1,236 after ART initiation. Insufficiency was defined the same way as the European measurement in Table 1, but deficiency was defined as less than 30 nmol/L. [5]

Insufficiency was found in 804 measurements (54%), while deficiency was found in 98 (7%). In 116 patients measured pre- and post-ART initiation in the same season, there was a non-significant drop of vitamin D levels (average of 7.57 nmol/L per year; p=0.11).

The following were significantly associated with deficiency versus normal values (adjusted odds ratios):

• Age (per 10 years older) (OR 1.53; 95%CI 1.11–2.09;  p=0.009)

• Non-Caucasian origin  (OR: Caucasians were 0.17 times as likely to have deficiency; 95%CI 0.07–0.42; p=0.0001)

• Lower CD4 count (per 100 cells/mm3) (OR: Higher CD4 count was 0.9 times as likely to have deficiency; 95%CI 0.82–0.99; p=0.04)

• Lower BMI (OR: for each unit higher, 0.9 times as likely to have deficiency; 95%CI 0.83–0.98; p=0.01)

• NNRTI vs PI use (OR: participants on PI regimens were 0.47 times as likely to have deficiency; 95%CI 0.27–0.84; p=0.01)

• Season:  (with summer as reference: OR of autumn: 1.24; 95%CI  0.51–3.05; p=0.64; winter: 4.84; 95%CI 2.07–11.33; p=0.0003; spring: 8.3; 95%CI 3.61–19.09; p=0.0001)

During questions, d’Arminio Monforte stated that they had found that deficiency was associated with clinical events, in particular cardiovascular ones, but the direction of any causal effect, if any, was unclear. She also pointed out that in the HIV-negative population obesity is associated with deficiency, while in this cohort the opposite occurred: lower BMI was associated with deficiency.

Swiss cohort

Christoph Fux of University Hospital, Bern presented data on vitamin D deficiency in 211 patients in the Swiss HIV cohort, half of whom were measured in spring and half in autumn. As with the Italian cohort, insufficiency was defined the same way as the European measurement in Table 1, but deficiency was defined as less than 30 nmol/L.  [6]

At baseline before ART initiation, there was 14% deficiency in autumn and 42% deficiency in spring. After 12 months of ART – at which point all patients were virologically suppressed – this was virtually unchanged (47% in spring, NS). White race was associated with significantly higher vitamin D levels than Asian, Hispanic and black race.

Interestingly, measurements of 1α-25(OH)2D were also taken and it was found that there was some compensation, ie when 25(OH)D levels were lower, there was a higher ratio of the active metabolite to 25(OH)D.

In multivariate analysis, white race (14.1 umol/L higher; p=0.001) and, surprisingly, duration of HIV by 10 years (6.4; p=0.02) were associated with higher 25(OH)D levels. While BMI (-0.7; p=0.05), active IDU (-11.2; p=0.02), spring (-17.7; p<0.001) and NNRTI use (-8.2; p=0.002) were associated with lower levels. Sex, age, HCV positivity, cGFR <60mL/min, previous AIDS, CD4 count and tenofovir use were not significantly related to lower levels.

Interestingly, for 1α-25(OH)2D levels, the results were different. Neither race nor season were significant. BMI was positively associated with vitamin D levels (1.7; p<0.001), as was tenofovir use (7.8; p=0.02).  HCV positivity was negatively associated  (-9.1; p=0.04) as was previous AIDS (-11.6; p=0.007) and CD4 count by 100 cells (-2.6; p=0.003).

Tanzanian cohort

Saurabh Mehta of Harvard Medical School presented data from Tanzania on the association between vitamin D levels and wasting, acute respiratory infections and thrush. They defined low vitamin D level as less than 32 ng/mL. Vitamin D levels were measured in 884 pregnant Tanzanian women who were followed up for a median of 70 months. In January, this research group published an article in PloS One showing that low vitamin D levels are associated with increased HIV disease progression (RR 1.25; 95%CI 1.05–1.5) and anemia (RR 1.46; 95%CI 1.09–1.96). Women in the highest vitamin D quartile had a 42% lower risk of all-cause mortality (RR 0.58; 95%CI 0.4–0.84). This group has also previously published a widely cited study showing that a vitamin supplement delayed disease progression and mortality in this cohort, but the supplement did not contain vitamin D  [7-9].

In this study, low vitamin D was associated with a 45% higher risk of wasting (BMI <18kg/m2; p=0.03), a higher incidence of acute respiratory infections (RR 1.28; 95%CI 1.05–1.55) and a much higher incidence of thrush (RR 2.92; 95%CI 1.43–5.96). They also found a linear relationship between any vitamin D level and wasting.

During questions, Mehta pointed out that no association was found with seasonal factors (Tanzania is near the equator). He also said that they found no association between vitamin D and TB, but did find an association between children born to mothers with deficiency and TB. When asked to comment on which way the association between wasting and vitamin D went, Mehta explained that the vitamin D level was measured at baseline when women with wasting were excluded from analysis and that the wasting in this cohort came subsequent to the vitamin D measure.

WIHS cohort

Audrey French of Rush University Medical Centre presented data from a cross-sectional sub-study of the Womens’ Interagency HIV Study (WIHS), whose objective was to see if there was an association between vitamin D deficiency and bacterial vaginosis. WIHS is a longitudinal multi-site study of about 3,000 women with and without HIV. The substudy is from Chicago and New York City and includes 480 HIV-positive and 122 HIV-negative participants.

Bacterial vaginosis was diagnosed using the Amsel criteria. Vitamin D insufficiency was defined as 20-30ng/mL and deficiency as less than 20ng/mL. Prevalence of deficiency was 60% and insufficiency was 24%. Black race was the only predictor of deficiency in an analysis using demographics, socioeconomic status and HIV associated variables including HIV status. Factors associated with bacterial vaginosis in multivariate analysis were black race (OR 6.08; 95%CI 2.66–13.9), number of recent sexual partners (OR 2.3; 95%CI 1.12–5.06) and vitamin D deficiency (OR 2.3; 95%CI 1.02–5.19). The correlation co-efficient between vitamin D and bacterial vaginosis was -0.14 (p<0.001).

During question time, it was stated that vitamin D status was not associated with bone mineral density. Two researchers indicated that in their US cohorts of HIV-positive and HIV-negative people, they had not found an association between HIV status and vitamin D status. But another researcher indicated that a Swiss study had found a difference.

The need for a clinical trial

Michael Yin summarised the session, emphasising the many unanswered questions, lack of data and need for clinical trials of vitamin D. Study participants to consider include people initiating ART especially efavirenz, people who are ageing and people in resource limited high TB prevalence areas. Study endpoints to consider are bone density, muscle mass, fall risk, insulin resistance, cardiovascular disease, CD4 count, HIV progression, opportunistic infections and other measures of innate and adaptive immunity. He suggested a vitamin D supplement dose of 1000–2000 IU per day was a reasonable dose. [10]

He also described unanswered questions about screening. He asked if there should be universal screening (adopted by European AIDS Clinical Society) or targeted screening aimed at older people, black race people, people with previous fractures or low bone mass density, people who are frail or have sarcopenia and patients on efavirenz. He suggested that a target in patients of 40–60 ng/mL or 100–150 nmol/L should be aimed for.

During questions, Yin was asked about the risk of high dosages. He described a study that looked at vitamin D and its correlation with calcium levels. Hypercalcaemia was only seen at levels of 200-240 nmol/L, which was far higher than could be reached with the doses he was proposing. Another questioner asked whether clinical or surrogate end point markers should be the endpoint of a vitamin D trial. Reiss responded that a trial looking at clinical endpoints would have to be too large and consequently surrogate endpoints would have to be used.

comment

These studies contribute to our understanding of vitamin D deficiency in people with HIV. However, there remain many unanswered questions relating to the clinical implications of vitamin D deficiency, how and what to measure and appropriate target levels in different populations, if supplementation is indicated.

In the absence of data from clinical trials, most HIV guidelines defer to national protocols for management of bone disease, recommending supplementation for patients with deficient levels.

While a Cochrane review found statistically significant evidence for prescribing vitamin D to patients taking systemic corticosteroids, other reviews found insufficient evidence to show supplementation prevents fractures in older people, or during pregnancy or to treat chronic kidney diseases or children with cystic fibrosis.

Peter Reiss noted that the size and cost of an adequately powered randomised trial probably makes this unlikely.  Management should therefore also include lifestyle changes, such as greater exposure to sun and improved diet and that this may be sufficient for some patients.

References

Unless stated otherwise, all references are to the Programme and Abstracts of the 17th Conference on Retroviruses and Opportunistic Infections. 16-10 February 2010, San Francisco. All oral abstracts are available as webcasts.

http://www.retroconference.org

1. Reduced levels of vitamin D in patients taking efavirenz. HTB, November/December 2009.

http://i-base.info/htb/6127

2. Vitamin D deficiency, supplementation and tenofovir. HTB, May/June 2009.

http://i-base.info/htb/1688

3. Got Milk? Vitamin D deficiency prevalence and associations. CROI 2010. Webcast session Feb 17 2010.

4. Dao C et al. Assessment of vitamin D levels among HIV-infected persons in the study to understand the natural history of HIV/AIDS in the era of effective therapy (SUN study). 17th CROI, 2010. Poster abstract 750.

http://www.retroconference.org/2010/Abstracts/36819.htm

5. Borderi M et al. Prevalence of hypovitaminosis D among HIV+ patients enrolled in a large Italian cohort. 17th CROI, 2010. Poster 751.

http://www.retroconference.org/2010/Abstracts/39276.htm

6. Mueller N et al. High Prevalence of severe vitamin D deficiency in cART naïve and successfully treated Swiss HIV patients. 17th CROI, 2010. Poster 752.

http://www.retroconference.org/2010/Abstracts/38991.htm

7. Mehta S et al. Vitamin D and HIV-related complications and HIV disease progression in women in Tanzania. 17th CROI, 2010. Poster 753.

http://www.retroconference.org/2010/Abstracts/39115.htm

8. Mehta S et al. Vitamin D status of HIV-infected women and its association with HIV disease progression, anemia, and mortality. PLoS One 2010 Jan 19;5(1).

http://www.ncbi.nlm.nih.gov/pubmed/20098738

9. Fawzi WW et al. A randomised trial of multivitamin supplements and HIV disease progression and mortality. N Engl J Med. 2004 Jul 1;351(1):23-32.

10. French A et al.  Vitamin D deficiency and bacterial vaginosis among HIV-infected and -uninfected women in the United States. 17th CROI, 2010. Poster 754.

http://www.retroconference.org/2010/Abstracts/37539.htm

In an oral presentation, James McIntyre showed data from the OCTANE/A5208 trial. This trial, conducted in seven African countries, was designed to evaluate which of two antiretroviral regimens is more effective in women previously exposed to single dose NVP and whether single dose NVP compromises subsequent NVP-containing HAART. [1]

OCTANE was composed of Trial 1 and Trial 2. Trial 1 women (n=243) were NVP exposed at least six months prior to the study and those in Trial 2 (n=502) were unexposed. Women in each trial were randomised to receive either NVP or lopinavir/ritonavir (LPV/r) in regimens with tenofovir (TDF) and emtricitabine (FTC). Women with CD4 <200 cells/mm3 were eligible.

The time from randomisation to death or virologic failure (defined as plasma viral load <1 log copies/mL below baseline 12 weeks after treatment initiation, or >400 copies/mL at or after 24 weeks) was the primary endpoint in both studies.

Trial 1 was stopped by the DSMB in October 2008 at a median of 66 weeks, after an interim analysis, which found LPV/r to be significantly more effective than NVP and associated with fewer side effects. We reported this data in previously in HTB. [2, 3]

It is notable that in this study the LPV/r arm performed extremely well with only 8% of women meeting an endpoint vs 26% in the NVP arm (adjusted HR 3.6; 95% CI 1.7–7.5).

Trial 2 was designed to assess equivalence (defined as 95% CI for the HR: 0.5–2.0) between the two treatment arms. As in Trial 1, women were followed for >48 weeks. This was an intent-to-treat analysis of 500 women (2 excluded): 249 in the NVP arm and 251 in the LPV arm.

Baseline characteristics were similar in both arms, median: age 34 years, CD4 121 cells/mm3 and viral load 5.15 log copies/mL. One woman in the LPV/r arm had received single dose NVP but was included in the analysis. In a random sample of 119 women, baseline NVP resistance was detected in 1% of women. The median duration of follow-up was 118 weeks; 14 women in the NVP and 6 in the LPV/r arms were lost to follow-up.

Dr McIntyre reported that 42 (17%) women in the NVP arm and 50 (20%) in the LPV/r arm reached the primary endpoint (HR 0.85; 95%CI 0.56–1.29). These results met the criteria for equivalence. The as-treated analysis results were similar (HR 0.71; 95%CI 0.45–1.13).

When the investigators broke down the composite endpoint to look at virologic failure and death separately, they found 15% vs 17% experienced virologic failure and 2% vs 3% died in the NVP and LPV/r arms respectively.

Overall, 93 women discontinued NVP or LPV/r permanently, 70 (28%) in the NVP arm and 23 (9%) in the LPV/r arm, HR 3.4 (95% CI 2.2-5.5). Of these, 35 (14%) in the NVP arm and 0 in the LPV/r arm discontinued due to adverse events, p<0.0001.

Grade 3 or 4 signs/symptoms while receiving NVP or LPV/r were reported in 75 (15%) women (14% in NVP, 16% in LPV/r arm), and 26% and 22% (respectively) had grade 3/4 laboratory test abnormalities. Dr McIntyre noted that the protocol took a conservative approach to adverse events for women receiving NVP but events in the LPV/r arm could be managed without a protocol-mandated switch in therapy.

In conclusion, the study reported that NVP+TDF+FTC and LPV/r+TDF+FTC were equivalent in treatment-naïve women. This suggests that the previously reported inferiority of NVP in Trial 1 was related to NVP resistance from single dose NVP exposure.

comment

James McIntyre remarked that these data are reassuring for programmes using nevirapine, particularly in Africa where it is a mainstay of antiretroviral regimens.

What remains unexplained is why the LPV/r arm in Trial 1 performed so well whereas in Trial 2 what we are seeing is similar to general experience.

When this was questioned after the presentation Dr McIntyre remarked that this raises “intriguing possibilities” and there may be some plausibility that nevirapine-induced mutations could have some effect on gag/pol cleavage causing conformational changes which may make protease enzymes less effective. If so, protease inhibitors would have less to inhibit, so would work better. He added that he knew of no evidence to support this!

It is perhaps worth noting that equivalence in this study is powered with an equivalence range from 0.5 to 2 – ie requiring a doubling or halving of the risk is still defined as ‘equivalent’.

When looking at absolute rates at other studies that use a tighter range, differences of up to 12% are typically viewed as being ‘non-inferior’. Using a doubling/halving in risk is stretching this even further.

References

Unless stated otherwise, all references are to the Programme and Abstracts of the 17th Conference on Retroviruses and Opportunistic Infections. 16-10 February 2010, San Francisco. All oral abstracts are available as webcasts.

http://www.retroconference.org

1. McIntyre J et al. Efficacy of ART with NVP+TDF/FTC vs LPV/r+TDF/FTC among antiretroviral-naïve women in Africa: OCTANE Trial 2/ACTG A5208. 17th CROI, 2010. Oral abstract  153 LB.

http://www.retroconference.org/2010/Abstracts/39798.htm

Webcast: Treatment outcomes in women and children. Friday 9.30am.

http://www.retroconference.org/2010/data/files/webcast_2010.htm

2. OCTANE Trial DSMB finds ritonavir-boosted lopinavir superior to nevirapine in HIV-positive women previously exposed to single dose nevirapine. HTB, December 2008.

http://i-base.info/htb/261

3. Lopinavir/r containing regimen superior to nevirapine containing regimen in women previously exposed to single dose nevirapine. HTB, April 2009.

http://i-base.info/htb/1449

Several groups have documented high rates of HIV acquisition during pregnancy and breastfeeding.

Two oral presentations at CROI showed findings from investigations into HIV incidence and retesting among women in high prevalence settings in Africa.

John Kinuthia from the University of Nairobi, Kenya presented data from a study looking at HIV incidence among mothers accompanying their infants for routine 6-week immunisation at 6 maternal–child health clinics in Nairobi and Nyanza Province of Western Kenya. [1]

In this study, mothers completed a questionnaire, before their HIV test, that assessed sociodemographic characteristics, obstetric history, HIV risk perception, and participation in PMTCT programmes during their last pregnancy. The investigators compared characteristics of HIV-negative women who seroconverted during pregnancy and immediately post partum to those who did not.

Dr Kinuthia reported that 2035 out of 2135 (95.3%), mothers who had tested HIV-negative in pregnancy, accepted a repeat HIV test at the immunisation visit. Of these, 53 (2.6%) were HIV-positive, giving an overall estimated HIV incidence of 6.8 (95%CI 5.1–8.8) per 100 woman-years.

The mean age of the mothers was 23.7 years. Of these 86.8% were married, 7.1% in polygamous marriages and 29.4% were employed.

Mothers who seroconverted were more likely to be employed (45.3% vs 29.0%, p=0.01), married (96.2 vs 86.6%, p=0.04) and from a higher HIV prevalence region (60.4% in Nyanza vs 28.8% in Nairobi, p<0.001).

Married women, in a polygamous relationship were significantly more likely to seroconvert (19.6% vs 6.7%, p<0.001). Age, educational level, HIV risk perception, history of physical assault, and economic status were not associated with seroconversion. In multivariate analysis, region (OR 3.6; 95%CI 2.1–6.4, p<0.001) and employment (OR 1.9; 95%CI 1.1–3.3, p=0.03) were independent predictors of seroconversion.

Dr Kinuthia suggested that the limitations of the study included no data on the timing of the mothers’ initial HIV test, nor their partners’ status.

He concluded that repeat HIV testing in early postpartum was highly acceptable and resulted in detection of substantial HIV incidence. He noted that the incidence in pregnancy and early postpartum in this study compared to that among cohorts of sex workers and women in discordant relationships. He stressed the need for an urgent review of services for negative pregnant women in regions with high HIV seroprevalence and interventions such as couple counselling and testing, the promotion of safer sex in pregnancy and awareness of the risk of infection and in turn MTCT.

Following on from this was a presentation from Mary Pat Kieffer from the Elizabeth Glaser Pediatric AIDS Foundation, showing data from a study in which retesting in maternity facilities was used to provide interventions for women who became infected late in pregnancy. [2]

Swaziland has a very high rate of HIV prevalence among pregnant women (42%) and a high uptake of PMTCT.

The primary objective of the study was to evaluate the effectiveness of a provider focused intervention in increasing ARV coverage at time of delivery. As secondary objectives the investigators sought to determine HIV incidence in late pregnancy and the number of newly-indentified HIV-positive women in maternity. They also looked at whether provision of nevirapine to women who refused testing increases coverage.

Maternity staff received an extra one-day training based on the women’s status on arrival. This included:

• Testing women with unknown status and offering nevirapine (NVP) to those who declined.

• Routine HIV retesting as standard of care for women who tested negative three months or more earlier (Swazi guidelines).

• Ensuring all newly identified women receive ARV treatment or prophylaxis.

Women received antiretrovirals in accordance with Swazi national guidelines (NVP+3TC+AZT for women meeting criteria for treatment or short course AZT plus single dose NVP and AZT+3TC “tail” prophylaxis for healthier women).

Sampling used 6 public maternity sites, matched as pairs and randomised within the pair to intervention or control.

Data on testing and ARV prophylaxis were collected through questionnaires and MoH registers.

Cord blood samples were collected as dried blood spots (DBS) and tested for HIV. All positive DBS were tested for NVP. Coverage was defined as number of cord bloods with detectable NVP.

The investigators found 1398/2444 (62.3%) women enrolled in the study had previously tested negative in pregnancy.

Overall NVP was detected in 75% cord bloods, this was significantly higher in the intervention than the control groups, 80% vs 69%, p=0.0001. Dr Kieffer noted that the only group of women for whom there was no significant improvement was those who already knew their status and had taken their ARV prophylaxis at home (p=0.23).

The most critical finding of this study was the high level of HIV incidence in pregnancy: 4.4% women who were HIV negative in ANC were positive at time of delivery giving a rate of 16.75 new infections per 100 person-years. Dr Kieffer suggested that, like the previous data from Nyanza, this rate is similar to cohorts of sex workers and IDU.

She compared these rates to earlier data from Rakai that showed 1.1 per 100 person years incidence in non-pregnant women vs 2.3 in pregnant women per 100 person years.

The second critical finding was that ARV provision almost doubled for women who seroconverted during pregnancy (n=58), 26% vs 54% in control vs intervention groups respectively (p=0.03).

Dr Kieffer explained that this was still only reaching about half those that seroconverted. Control sites had retested 14% (135/ 959) HIV^-negative women, compared to 45% (528/1185) women at intervention sites p<0.0001; relative risk 3.17 (95%CI 2.67–3.74). The primary reason for this was the Swazi guidelines only recommend retesting after 3 months or more, but a significant proportion of women (38%) had been previously tested for HIV earlier than this so were not eligible for retesting.

“Reaching women who become infected late in pregnancy cannot be an afterthought for PMTCT programmes” she said.

Like the previous study these data highlight the need for interventions to identify and provide ARV prophylaxis to women who seroconvert in pregnancy and prevention strategies to enable HIV-negative women to remain negative.

comment

This issue is important and was also raised by Lu et al at CROI last year. [3]

The question of poor test performance discussed by Black et al in AIDS was also discussed following the presentation. [4]

Whether these transmissions can be attributed to HIV incidence in pregnancy or poor test performance, unidentified HIV positive women in pregnancy remain a barrier to the eradication of paediatric HIV.

References

Unless stated otherwise, all references are to the Programme and Abstracts of the 17th Conference on Retroviruses and Opportunistic Infections. 16-10 February 2010, San Francisco. All oral abstracts are available as webcasts.

http://www.retroconference.org

1. Kinuthia J et al. Co-factors for HIV Incidence during Pregnancy and the Postpartum Period. 17th CROI, San Francisco, 2010.  Oral abstract 155.

http://www.retroconference.org/2010/Abstracts/38372.htm

Webcast: Treatment outcomes in women and children. Friday 9.30am.

http://www.retroconference.org/2010/data/files/webcast_2010.htm

2. Kieffer MP et al. Repeat HIV testing in labor and delivery as a standard of care increases ARV provision for women Who Seroconvert during Pregnancy. 17th CROI, San Francisco, 2010.  Oral abstract 156.

http://www.retroconference.org/2010/Abstracts/37241.htm

Webcast: Treatment outcomes in women and children. Friday 9.30am.

http://www.retroconference.org/2010/data/files/webcast_2010.htm

3.  High rates of HIV acquisition in pregnancy and post partum in Francistown, Botswana. HTB April 2009.

http://i-base.info/htb/1425

4. Black V et al. High HIV incidence or poor test performance? AIDS, 23 October 2009. Vol 23; (16) p2234-2235.

Of all the antiretrovirals, efavirenz attracts the most controversy with regard to use in pregnant women. Two posters at CROI looked at birth outcomes among mothers who received efavirenz in pregnancy. [1, 2]

Daniel Westreich and colleagues analysed prospective data from Themba Lethu Clinic in Johannesburg. They examined the risk factors for pregnancy after initiation of HAART using Cox proportional hazards regression and looked at birth outcomes in women receiving efavirenz.

The investigators reported that of 5011 women initiating HAART between April 1 2004 and March 31 2007, 351 (7%) became pregnant giving a rate of 4.1 pregnancies per 100 woman years (95% CI 3.7–4.5).

They found that this was less among older women (>35 years) and those with lower CD4 counts or employed.

The investigators noted that although women who initiated HAART with efavirenz based regimens were less likely to become pregnant that than those starting with nevirapine, HR 0.6 (95% CI 0.4–0.8), 68% (n=238) of pregnancies occurred in women receiving efavirenz.

The investigators looked at 136 of the women receiving efavirenz for pregnancy outcome. They reported three maternal deaths, 39 women lost to follow up and one who refused to be interviewed. In addition 12 women were still pregnant at the time of analysis.

Out of 81 pregnancies analysed, 8 were voluntarily terminated and 13 miscarried. Of the remaining 60 live births, 41 were examined using the Denver Development Screening Test. According to this scale, 30 infants were classified as “within normal limits” and 11 (>25%, 95% CI 14–43) were  “suspect” for developmental delay. The investigators did not find any congenital abnormalities among the infants examined.

The investigators rightly suggested that further study including a comparison group is required to evaluate whether suspected neurodevelopmental delays or miscarriages are associated with efavirenz use. And they wrote, “These results suggest that the risk of efavirenz in pregnancy may be less catastrophic than feared”.

A related poster authored by Daniel Conway and colleagues reported findings from an analysis of prevalence of congenital abnormalities among antiretroviral-exposed infants in IMPAACT P1025.  This US cohort study enrolled all women and infants in P1025 born between 2002 and 2007 (n=1306) during pregnancy or up to two weeks post-partum.  No information was provided regarding prospective or retrospective enrollment, that is, whether any women/infants could be enrolled after an anomaly had already been diagnosed.

A total of 1112 infants were eligible for analysis. Infants were examined for congenital anomalies and reviewers were blinded to in utero antiretroviral (individual drugs and classes) exposure. In utero exposure was classified as 1st, 2nd/3rd trimester and unexposed. The investigators used logistic regression to estimate the relationship between congenital anomalies and antiretroviral exposure.

The investigators reported 80 congenital anomalies among 61 infants, a rate of 5.49/100 live births (95%CI 4.22–6.99). These were broken down into organ systems involved: cardiovascular (n=33), genitourinary (n=7), renal (n=8), musculoskeletal (n=15, including accessory digits of hand or foot, n=7), craniofacial (n=3), central nervous system (n=3), chromosomal (n=3), eye (n=3), gastrointestinal (n=5).

This study reports that first trimester exposure to efavirenz was associated with a significantly increased risk of congenital anomalies (OR 2.89; 95%CI 1.15–7.25) compared to 2nd/3rd trimester exposure. No information was provided regarding the types of anomalies associated with efavirenz exposure.

They did not find any other classes of antiretrovirals nor individual drugs (only data for efavirenz and AZT were shown) to be associated with increased risk of anomalies. Covariates including ethnicity, maternal age and substance use (tobacco, alcohol and recreational drugs) were not significantly associated with increased risk of congenital anomalies.

comment

Because of the uncertainties about efavirenz use in pregnancy, all new information on this subject is worth reporting.

Unfortunately neither of the posters summarised here showed enough data to make their interpretation straightforward and both studies seem underpowered.

The Themba Lethu Clinic analysis does not report baseline data and has high loss to follow up. Only the abstract is on the conference website so it was not possible to double-check these data.

The P1025 numbers are also small, about 1/10 of the APR, including those with efavirenz first trimester exposure (47 vs 501). [3] They do not report what the 6 anomalies with first trimester efavirenz exposure were, which seems very important in view of the monkey data.  The only other antiretroviral they report on individually is AZT.

Some of the P1025 data are already in the APR though it is not clear which, and not all women were enrolled into this study before pregnancy outcome was known which would make them ineligible for the APR. Retrospective observations of birth defects cannot be used to determine birth defect prevalence, because of differential reporting bias, that is, that a foetus or infant with a birth defect would be more likely to be enrolled than one with an unknown or normal outcome.

Good data to guide recommendations in this area are urgently needed including other important outcomes such as spontaneous abortion and termination of pregnancy.

References

Unless stated otherwise, all references are to the Programme and Abstracts of the 17th Conference on Retroviruses and Opportunistic Infections. 16-10 February 2010, San Francisco.

1. Westreich D et al. Pregnancy, efavirenz, and birth outcomes in Johannesburg. 17th CROI, San Francisco, 2010.  Poster abstract 922.

http://www.retroconference.org/2010/Abstracts/38870.htm

2. Conway D et al. Prevalence of congenital anomalies in infants with in utero exposure to antiretrovirals: IMPAACT P1025. 17th CROI, San Francisco, 2010.  Poster abstract 923.

http://www.retroconference.org/2010/Abstracts/36925.htm

3. Antiretoviral pregnancy registry.

http://www.apregistry.com/forms/interim_report.pdf

AZT is the only antiretroviral licensed for use in pregnancy. In resource rich settings AZT-containing regimens are becoming less and less common and in turn increasing numbers of women are becoming pregnant while receiving non AZT-containing HAART, or initiating non-AZT-containing HAART in pregnancy.

A poster at authored by Shema Tariq and colleagues reported findings from an investigation into the risk of detectable maternal viral load (VL) at delivery, congenital abnormality and mother to child transmission (MTCT) in pregnancies among women receiving HAART containing and not containing AZT. [1]

This analysis combined data from the National study of HIV in Pregnancy and Childhood (NSHPC) and the European Collaborative Study (ECS).

All live singleton births from 2000 to 2009 with >14 days of HAART in pregnancy were included. The investigators used logistic regression to estimate adjusted odds ratios (AOR).

A total of 7353 (6310, NSHPC and 1263, ECS) pregnancies were included, of which 1199  (15.8%) were exposed to non-AZT HAART. Of this group, 23.2% and 71.3% were on HAART prior to conception in the AZT and non-AZT groups respectively. Exposure to non-AZT HAART increased over time: 2000–2002 19.6% vs 17.1%, 2006–2009 41.4 vs 58.7% women received AZT vs non-AZT HAART respectively, p<0.01.

Tenofovir and abacavir was the most commonly used non-AZT drug in this cohort; approx 45% and 35% respectively.

In multivariate analysis the investigators found no evidence of associations between non-AZT HAART and detectable viral load at delivery, risk of congenital abnormalities (including in a sub-analysis of pregnancies with 1st trimester exposure or rate of MTCT, see Table 1.

Table1. Maternal and infant outcomes AZT vs non-AZT HAART multivariate analysis, AOR (95% CI)

The investigators noted that information on maternal VL at delivery was missing for 45% of pregnancies however the proportions of missing data were similar for both groups. Additionally HIV status was not yet reported for 20% of infants, mainly those born recently. They suggested that this is unlikely to introduce bias.

The investigators described these results as reassuring and that continued monitoring of pregnancy outcomes and longer term consequences of in utero exposure to these antiretroviral drugs is required.

Ref: Tariq S et al.  Pregnancy outcomes in HIV-infected women using non-zidovudine HAART in Europe: 2000 to 2009. 17th CROI, San Francisco, 2010.  Poster abstract 895.

http://www.retroconference.org/2010/Abstracts/37281.htm

Women who do not need treatment for their own HIV in resource-rich countries generally receive a short course of HAART in pregnancy to prevent mother to child transmission (MTCT).

It is considered a safe option for women with low or undetectable viral loads (VL) to choose vaginal delivery. BHIVA guidelines recommend a cut off of <50 copies/mL and the US guidelines <1000 copies/mL.

However the optimum timing to initiate short course HAART and achieve an undetectable viral load is uncertain.

A poster authored by Phillip Read and colleagues showed findings from a retrospective UK study across five centres in London and the South East, conducted to provide data for clinicians for the timing of short course HAART in pregnancy.

All available data were included for women commencing boosted PI, NNRTI or triple NRTI based HAART from 2000 onwards

In this study demographics, gestation, drug class, CD4 count, and VL results were collated. VL data were right-censored at delivery date and drug regimen analyses were intent-to-treat. Survival curves for reaching a viral load <50 copies/mL were stratified by VL at initiation of HAART. Cox’s proportional hazards regression model adjusted for demographics and immuno-virological parameters.

In this study, 439 pregnancies met the inclusion criteria and 378 had sufficient data for analysis.

Of those evaluated, 70% of women were of black African origin and their mean age at conception was 29.9 (range 14.7–49.8) years. Median pre-treatment CD4 and viral load was 330 cells/mm3 (IQR 195–470) and 8243 copies/mL (IQR 2341-32,640).

For their regimen, 246 women (65%) started PI-, 129 (34%) NNRTI-, and 3 (1%) NRTI-based HAART, initiated at a median of 23.2 weeks gestation (IQR 20.4 to 26.3).

By their delivery date (mean 38 weeks), 292 (77%) women achieved VL <50 copies/mL after a median of 58 days. Pre-treatment VL was associated with both the time taken and the proportion achieving a VL  <50 copies/mL at delivery, p<0.001.

A baseline viral load of <10,000, 10,000 to 50,000, 50,001 to 100,000, and >100,000 resulted in 91%, 73%, 54%, and 37% of women achieving <50 copies/mL at delivery, respectively.

In multivariate analysis, the hazard ratio (HR) for a NNRTI regimen achieving a viral load <50 copies/mL compared to a PI was 0.7 (95% CI 0.52 -0.94). If VL was >10,000, 58% of PI and 66% of NNRTI regimens achieved <50 copies/mL.

When baseline VL was <10,000 copies/mL, gestation at initiation of HAART did not significantly change the probability of a VL <50 copies/mL at delivery. With a baseline VL of 10,000–50,000 copies/mL, the HR for a VL <50 copies/mL declined to 0.51 if HAART was initiated after 23.3 weeks (p<0.01) while if viral load was >100,000, starting HAART before 20.4 weeks gave a HR of 0.2 (p <0.01) compared with 0.1 if started after 20.4 weeks (p <0.01).

The investigators concluded with four key messages:

• Women with a VL >10,000 copies/mL should commence HAART by 20.4 weeks
• Women with a VL >100,000 copies/mL should commence HAART without delay
• If the VL is <10,000 copies/mL, HAART may be deferred to 26 weeks
• If the VL is >10,000 copies/mL NNRTI-based HAART, where appropriate, may be more successful

And they noted: “Final decisions on mode of delivery often depend on the VL at 36 weeks gestation and this needs to be taken into account when starting HAART based on these data”.

comment

This analysis provides useful data to guide when to commence short course HAART in pregnancy.

Presumably, a larger proportion of women would commence long term treatment if they were starting according to current guidelines, as the median baseline CD4 count in this data set was 330 cells/mm3 (IQR 195–470), and previous guidance used a 200 CD4 cells/mm3 threshold at which to start HAART.

Ref: Read P et al. When Should HAART be initiated in pregnancy to achieve an undetectable viral load? 17th CROI, 16-19 February 2010, San Francisco.  Poster abstract 896.

http://www.retroconference.org/2010/Abstracts/37418.htm

Several posters at CROI 2010 showed findings from studies looking at outcomes in infants exposed to maternal antiretrovirals in utero.

Tenofovir exposure in DART

Enniie Chidziva and colleagues from the DART trial evaluated infants born to women mainly receiving tenofovir (TDF) based HAART in Uganda and Zimbabwe from 2004 to 2009. [1]

We have reported earlier results from the DART trial and pregnancy outcomes in previous issues of HTB. [2, 3]

During DART there were 223 live births with 6 infant deaths; 217 infants were alive two weeks after birth. Of these 129 (59%) were exposed to TDF in utero. Infants were evaluated in DART and in a separate follow up study.

The investigators reported that congenital abnormalities occurred in 7/217 (3%) of infants overall and 4/129 (3%) with TDF exposure. The abnormalities were: talipes 3 (2 with TDF exposure), cardiac 1, hydrocephalus 1(with TDF exposure), skin tag 1 (with TDF exposure) and undescended testes 1.

The majority 182/217 (84%) of infants were enrolled in the infant follow up study.  At their last visit they were a median age of 26 months (IQR 13–39); 69% were <12 months of age. The investigators noted that infants who were not enrolled in the follow up study were likely to have been born during the earlier part of the trial.

Prophylaxis was given to 152/182 (84%) of infants  (single-dose nevirapine 44%, AZT 18%, sd NVP+AZT 23%, other 15%)

Of the 182 infants, 73 were ever breastfed for median 92 days (range 5-1186 days). Unadjusted HR for currently BF vs never BF 0.45 (95% CI 0.05–3.62) and for stopped vs never BF 0.7 (95% CI 0.19–2.57, p=0.59).

Of the 171 children tested, all were HIV-negative, 3 were lost to follow up and 8 died before testing. Fourteen children died at a median age of 9.4 months, giving 6% 12-month mortality. Of these, 8 had in utero TDF exposure, 6 were HIV-negative and 8 untested.

Only 4/386 creatinine and 7/310 phosphate measurements were abnormal, all were grade 1 and confined to 7 children of which 4 were exposed to TDF in utero (3 throughout pregnancy and one 61% of time in utero). There was no evidence of an effect of TDF in utero on growth after 48 weeks (p=0.31) and there were no bone fractures.

Additionally, an Italian cohort study reported by Alessandra Vigano and colleagues showed that exposure to TDF during the second and third trimesters of gestation, when bone formation occurs, does not impair bone mass and bone metabolism in HIV-negative children born to HIV-positive women. [2]

Mashi and Mma Bana

Two studies with data combined from the Mashi and Mma Bana PMTCT trials in Botswana looked at infant anaemia and birthweight respectively. [5, 6]

We have reported on both trials in previous issues of HTB. [7, 8, 9, 10, 11]

Scott Dryden-Peterson and colleagues compared the incidence of severe and life-threatening (grade 3 or 4, DAIDS 2004 toxicity tables) anaemia in breastfed (BF) infants exposed to HAART in utero with BF and formula fed (FF) infants exposed to AZT in utero in these trials.

Endpoints were incidence of first severe anaemia from birth to 7 months and the analyses used scheduled measurements of first born uninfected infants.

A total of 1788 infants met the inclusion criteria (1096 Mashi, 692 Mma Bana). Of this group, 743 were exposed to maternal HAART (AZT+3TC+LPV/r or AZT+3TC+NVP), one month of post natal AZT and BF (categorised as HAART+BF; 517 to in utero AZT, 6 months of post-natal AZT, and breastfeeding (AZT+BF); and 528 infants to in utero AZT, 1 month of post-natal AZT, and formula feeding (AZT+FF).

The investigators reported there were 126 infants with severe anaemia by 7 months with a cumulative incidence of 12.6 % (n=89) in HAART+BF, 5.4 % (n=26) in AZT+BF, and 2.3 % (n=110 in AZT+FF.

Severe anaemia occurred more frequently among HAART+BF infants than either AZT+BF infants (OR 2.51, 95% CI 1.59-3.95), or AZT+FF infants (OR 6.11, 95% CI 3.2-11.6), both p<0.0001.

In multivariate analysis, predictors of severe anaemia (AOR; 95%CI) were:  HAART+BF (2.4; 95%CI 1.5–3.8 and 5.7; 95%CI 3.0–10.7) compared to AZT+BF and AZT+FF, respectively; low birth weight <2.5 kg (2.4; 95%CI 1.5–3.9); and male sex (1.5; 95%CI 1.0–2.2). Maternal CD4, VL, haemaglobin, education, income, study site and gestation at delivery were not significantly associated with severe anaemia.

Birthweight <2.5kg occurred in 103 (13.97%), 43 (8.4%) and 31 (5.9%) of infants in the HAART+BF, AZT+BF and AZT+FF groups respectively.

The investigators reported no differences in infant anaemia according to maternal HAART regimen. Microcytosis or hypochromia occurred in 39/89 (43.8%) infants in the HAART+BF group, with severe anaemia.

Patients with severe anaemia were treated with iron/multivitamin supplementation, and 10 infants (7.9%) received transfusions. Of those who improved to grade <3 with iron/multivitamin supplementation alone this occured in <30 days in 43 (34%), 31–90 days in 50 (39.7%) and >90 days in 18 (14.3%) infants. Three (2.4) infants died while grade 3–4 and 2 (1.6) were lost to follow up.

The investigators concluded: “The clinical implication of this finding requires further investigation to ensure that the established benefits of using HAART for MTCT prevention are maximised for all infants.”

The same research group looked at the impact of HAART and short course AZT on longitudinal growth in a subset of Mashi and Mma Bana infants. They noted that HAART for PMTCT may lead to lower birth weight but longitudinal effects of in utero exposure on infant growth have not been previously reported.

In this analysis, Kathleen Powis and colleagues evaluated breastfed, HIV-uninfected infants born >37 weeks and exposed in utero to at least 2 weeks of either HAART or AZT. Infants in the HAART-exposed group received postnatal AZT for 1 month. Infants in the AZT-exposed group received 6 months of AZT-prophylaxis during breastfeeding.

The investigators calculated gender-based weight-for-age, length-for-age, and weight-for-length z-scores were using WHO Child Growth Standards. They compared mean z-scores using the Student’s t- test and analysis of response profiles.

This analysis included 437 AZT-exposed infants from Mashi, and 592 HAART-exposed infants from Mma Bana.

Median maternal baseline CD4 counts were 393 and 337 cells/mm3 (p=<0.001) and median viral load 4.34 and 4.19 log copies/mL (p=0.04) for Mashi and Mma Bana women, respectively  Demographics were similar between cohorts.

The median time of in utero AZT exposure was 5.7 weeks (range 2.0–10.9 weeks), and median in utero HAART exposure was 12.1 weeks (range 2.6–22.3 weeks).

Median birth weights were 3.1kg in AZT-exposed and 3.0kg in HAART-exposed (p<0.001). HAART exposed infants had significantly lower mean weight-for-age, length-for-age, and weight-for-length z-scores (p<0.001, p = 0.02, and p= 0.007, respectively).

However, the investigators reported that by 3 months of age the infants’ median weight was no longer different by exposure group, and their weight remained similar to 6 months. Mean weight-for-age differed over time by exposure group (p <0.001). Length-for-age remained lower in the HAART-exposed group to 6 months of age, but weight-for-length improved significantly over time compared with AZT-exposed infants (p<0.001).

They noted that the proportions of infants with z-scores >2 standard deviations below the mean were not different between exposure groups.

These early developmental comparisons are useful and longer-term comparisons are planned. The investigators wrote: “The early correction of birth weight differences among HAART exposed infants is reassuring for programmes utilising maternal HAART for treatment and PMTCT.”

comment

Both DART and the Botswana group continue to provide urgently needed and excellent data on maternal /infant health and outcomes.

References

Unless stated otherwise, all references are to the Programme and Abstracts of the 17th Conference on Retroviruses and Opportunistic Infections, 16-19 February 2010, San Francisco.

1. Chidziva E et al. Outcomes in infants born to HIV-infected mothers receiving long-term ART in the DART trial, 2004 to 2009. Poster abstract 924.

http://www.retroconference.org/2010/Abstracts/38485.htm

2. Pregnancy outcomes in the DART trial. HTB, April 2007.

http://i-base.info/htb/2667

3.    Pregnancy rates and outcomes among women in the DART trial. HTB, October 2009.

http://i-base.info/htb/5945

4. Vigano A et al. Exposure during gestation to HAART, including tenofovir, does not impair bone status and metabolism in HIV-positive children born to HIV-positive mothers. Poster abstract 926.

http://www.retroconference.org/2010/Abstracts/38485.htm

5. Dryden-Peterson S et al. Increased risk of severe but reversible anemia following perinatal exposure to maternal HAART in infants in Botswana. Poster abstract 927.

http://www.retroconference.org/2010/Abstracts/37152.htm

6. Powis K et al. Impact of HAART and short-course zidovudine on longitudinal growth of HIV-exposed uninfected breastfed infants, Botswana. Poster abstract 928.

http://www.retroconference.org/2010/Abstracts/38185.htm

7. Mashi study – late breakers on breastfeeding. HTB, April 2005.

http://i-base.info/htb/7450

8. Risk factors for breastfeeding transmission, HTB, April 2008.

http://i-base.info/htb/1831

9. Breast milk, HIV suppression and decreased mother to child transmission. HTB, October 2005.

http://i-base.info/htb/7036

10. Response to nevirapine containing HAART following single dose nevirapine for PMTCT. HTB, February 2007.

http://i-base.info/htb/2745

11.  Reducing HIV transmission during breastfeeding. HTB, August 09.

http://i-base.info/htb/4466

Two posters looked at maternal TB in HIV-positive pregnant women.

Amita Gupta and colleagues from the SWEN India Study Group assessed the effect of maternal TB (prevalent or incident) between pregnancy to 12 months post-partum on risk of HIV MTCT. [1]

The SWEN trial compared the use of extended NVP to single dose NVP among breastfed infants to reduce MTCT of HIV. [2] A secondary objective of the trial was to look at maternal and infant morbidity and risk factors for MTCT.

Maternal VL, CD4, duration of breastfeeding, type of ART intervention and maternal hepatitis coinfection are well known to be factors associated with HIV MTCT. The role of maternal TB however has not been well characterised.

The investigators used multivariable logistic regression to determine the impact of maternal TB on HIV MTCT. They used WHO criteria to define TB cases and manual methods for AFB smear and culture.

They found, out of 783 mothers, with a median duration of follow up of 365 days (IQR 346-368), median CD4 472 cells/mm3 (IQR 317-667; 7% <200 cells/mm3), 3 had prevalent TB diagnosed in pregnancy and 30 had incident TB by 12 months post partum.

When they looked at maternal TB and HIV transmission, they found among mothers with any TB the HIV transmission rate was 30.3% (10/33) compared to 11.6% (87/750) among mothers without TB (OR 3.3 95%CI 1.5–7.2, p=0.02). When they restricted the analysis to maternal TB diagnosed before HIV transmission this gave a transmission rate of 20.7% (6/29) among mothers with TB compared to 12.3% (91/754) among mothers without, (OR 1.9 95% CI 0.8–4.8, p=0.17).

Mothers with TB had a higher baseline viral load than mothers who did not (85,651 copies/mL vs 37,639 copies/mL, p<0.01).

In multivariate analysis, maternal TB was associated with an OR 2.4 (95%CI 1.0–5.98), for HIV transmission adjusting for maternal factors (viral load, CD4, AZT, NVP, HAART) and infant factors (breastfeeding duration, infant NVP, gestational age, birth weight) associated with MTCT of HIV.

The investigators acknowledged that this analysis had limitations including that as a secondary trial endpoint it was likely to be underpowered, not all TB diagnoses were culture confirmed so some misclassification bias was possible and unmeasured confounders could possibly explain this finding.

However they concluded that maternal TB appears to be an important risk factor associated with HIV MTCT but that, “larger studies are needed to confirm this and to understand the pathogenesis since this appears to be independent of maternal viral load and CD4”.

Celine Gounder and colleagues from the Perinatal HIV Research Unit performed a cross sectional study across six antenatal clinics in Soweto to look at provider initiated screening for TB among pregnant women.

The study included all pregnant women >18 years of age presenting to the clinics, who gave verbal consent to participate. Women presenting with obstetric complications or medical emergencies, who declined or were unable to provide verbal consent, and prisoners were excluded.

Regardless of their HIV status, women were screened for symptoms of active pulmonary TB ie, cough for >2 weeks, sputum production, fevers, night sweats or weight loss.

Information on their demographics, HIV status, CD4 count, and prior TB and HIV history was also collected at the time of symptom screening.

Any woman with any symptom of active TB was then asked to provide a single sputum specimen, which was sent for sputum smear microscopy, mycobacterial culture and identification, and INH/RIF drug-susceptibility testing.

The investigators reported that 3970 pregnant women were enrolled in the study between December 2008 and August 2009 who had a median age of 26 years (range 18-49).

Of these women, 1492 (36%) were HIV-positive. The percentages of women with CD4 count in the following strata at diagnosis were: 2% (0–50), 17% (51–00), 30% (201–350), 22% (351–500), 19% (>500), and 9% unknown (the investigator noted that 49% had a CD4 count of <350 cells/mm3). Additionally, 5% had a prior history of TB disease, and 21% had previously been exposed to someone with active pulmonary TB.

The investigators reported that the prevalence of active pulmonary TB was 696/100,000 among HIV-positive pregnant women (10/1492 cases), and 200/100,000 among HIV-negative pregnant women (5/2478 cases). They did not identify any cases of MDR-TB.

The investigators wrote: “Provider-initiated TB screening among HIV-infected pregnant women is a high yield intervention, and should be integrated with PMTCT services.”

They added: “Given that 49% of the women had CD4⁺ T cell counts <350 cells/mm3, both ART and IPT should be considered in high TB/HIV prevalence settings.”

References

1. Gupta A et al. Maternal TB is associated with increased risk of HIV mother-to-child transmission. 17th Conference on Retroviruses and Opportunistic Infections (CROI), 16-19 February 2010, San Francisco.  Poster abstract 899.

http://www.retroconference.org/2010/Abstracts/37899.htm

2. Gounder C et al. Provider-initiated screening for TB among pregnant women in antenatal clinics in Soweto, South Africa. 17th Conference on Retroviruses and Opportunistic Infections (CROI), 16-19 February 2010, San Francisco.  Poster abstract 900.

http://www.retroconference.org/2010/Abstracts/37899.htm

Introduction

In this issue we continue reports from this European conference that is held every two years.

This year a comprehensive programme of lectures and sessions available as webcasts and podcasts and include many of the slide sets:

http://www.europeanaidsclinicalsociety.org

http://www.multiwebcast.com/eacs/2009/12th

Access requires a free one-time registration using the invitation code: EACS2009

It is disappointing that the abstracts from the meeting were not available online (as we went to press), and are only available as a subscription issue of HIV Medicine (2009, volume 10, issue S2).

The following reports are included in this issue.

• Screening for anal cancer recommended for HIV-positive men
• Once-daily darunavir/r monotherapy is suboptimal as initial regimen in treatment-naïve people
• Central fat accumulation remains a significant problem in patients starting HAART after 2005 with higher incidence in women compared to men
• Alendronate improves bone mineral density in HIV-positive people with osteoporosis at 96 weeks
• Pilot PK study of two generic paediatric formulations of lopinavir/ritonavir vs originator products
• TMC278 does not show teratogenic potential in animal models
• No clinically relevant interactions between TMC278 and oral contraceptives (norethindrone plus ethinylestradiol)
• Etravirine pregnancy data from five cases: no dose adjustment required
• Selected PK and drug interaction summaries at EACS

A plenary session at EACS reported that new evidence supports screening for anal cancer in HIV-positive men. [1]

This is important, because the increased risk of anal cancer in gay men, and particularly in HIV-positive gay men, has been highlighted for many years. Screening is safe and treatment is effective, especially when diagnosed early and the importance of establishing a screening programme has been repeatedly raised by community-based advocates for many years. Controversially, NHS guidelines do not recommend screening for anal cancer in the two largest risk groups: HIV-positive people and gay men.

The presentation, by Professor Mark Bower from the Chelsea and Westminster Hospital, London, who also chaired the panel for the BHIVA malignancy guidelines [2], clearly supported a review of the NICE decision. He also highlighted that current healthcare resources could not cope adequately with any significant increase in demand for screening.

The lecture started by highlighting the difficulties that are inherent in proving the clinical benefit for any screening programme, including for those that are now an integrated part of NHS care (such as cervical and breast cancer). Interpreting data is dependent on the choice of endpoints, control groups and inherent biases that generally will always support the benefits from screening, even if reduced mortality cannot be inferred.

For example, the incidence of a cancer, or advanced cancer, or even using reductions in cancer specific mortality as an endpoint, does not necessarily provide the data to prove the benefit of screening due to three important inherent biases in evaluating any screening programme are just as relevant in the context of anal cancer and HIV.

Firstly, lead time bias refers to greater survival time after diagnosis. This may be driven by the earlier diagnosis commonly resulting from any availability of broader screening and so survival time since diagnosis does not necessarily have any impact on final mortality. Awareness of a diagnosis for longer is dependent on effective treatment to translate into better prognosis and longer survival.
Secondly, lag time bias refers to the tendency for a greater proportion of cancers picked up in a screening programme to be more slowly progressing and less aggressive compared to symptomatic cancers picked up in any control group. In this case, slow growing cancers have a longer screening time in which to be detected and this will translate to an apparent improvement in survival.

Finally, over-diagnosis bias relates to picking up cancers in screening programmes which are never going to progress, or in patients who will die from unrelated or natural causes. This translates to a higher incidence of diagnosis in a screening population but a lower incidence of cancer-related mortality.

Despite the scientific difficulties associated with proving the effectiveness of a screening programme, the presentation outlined why anal cancers screening is now appropriate, based on proven incidence in this population and the effectiveness of treatment.

Although anal cancer was not included as an AIDS-defining malignancy in the US CDC 1993 definitions, unlike cervical cancer that has a similar incidence and etiology, a meta-analysis of major cohort studies has suggested that anal cancer is 20-50 times more common in HIV-positive people than age and gender matched general population. [3] This is an enormous relative risk: by comparison, tobacco smoking is associated with an approximate 17-fold increased risk for lung cancer.

The HIV effect is also more than a direct result of a weakened immune system: transplant patients who have artificially reduced immunosupression, only have a 4-5 fold increased risk of anal cancer.

Part, or much, or this increased incidence in HIV-positive gay men, may be related to the increased risk that was reported in MSM in pre-HIV data. [4]

Results from 11 linked HIV and cancer registries estimated a relative risk of 59 for HIV-positive MSM, but the same study also highlighted a 6-fold increased relative risk in HIV-positive compared to HIV-negative IDU’s. [5]

Population studies now estimate the incidence of anal cancer at 1.5 per 100,000 in the general population, but at 35 and 70 per 100,000 in the general population, gay men and HIV-positive gay men respectively. One cohort, in San Diego, reported an even higher rate of 224 in HIV-positive MSM. [6] This compares to an incidence of cervical cancer before the introduction of screening or 15 per 100,000.

Anal cancer does not appear related to CD4 count, and some studies have suggested that the incidence post-HAART may be increasing. [8] This can be balanced by evidence that suggests that, due to effective treatment, survival rates in the HAART era now approximate to that in HIV-negative cohorts (of around 75% at two years). [8]

A limited number of studies support a similar etiology between cervical and anal cancer, with 5% patients diagnosed with AIN2/3 and a similar proportion of patient after surgery for anal warts, progressing to anal cancer. A UCSF study published in 1997 in HIV-positive MSM suggested a progression rate of 20% from normal cytology to HSIL and a 60% progression rate for men diagnosed with LSIL to HSIL (with 5% reverting to normal). In 21 patients with invasive anal cancer (from the same UCSF cohort of 1700 men), the median time to progression from a diagnosis of HSIL was 47 months (range 4-139 months). [9].

However, natural history studies should now be considered unethical, as they would for cervical cancer, given the clear link between AIN2/3 and risk of progression to anal cancer and the availability of effective treatment.

Anal cytological screening is easy, well tolerated and acceptable to patients. Results show either normal cytology or one of three diagnosis: ASCUS, LSIL or HSIL (Abnormal Squamous Cells of Undetermined Significance; Low-grade Squamous Intraepithelial Lesions; or High-grade Squamous Intraepithelial Lesions).

In the screening algorithm developed by Joel Palefsky in the US, normal results should lead to repeat annual screening as routine follow-up. ASCUS, LSIL and HSIL should prompt high-resolution anoscopy, with repeat annual anoscopy for AIN1 and treatment for AIN2/3. [10] This is supported by several studies reporting acceptable rates of 34-83% sensitivity and 38-72% specificity for anal cytology compared to histology.

Finally, the recent availability of reasonable and established treatments for AIN2/3 (infrared coagulation with clearance rates 50-60% at one year; topical trichloroacetic acid; imiquimod with 40% resolution vs 8% control; and surgical anal mucosectomy), that argue for the reevaluation of anal cytological screening.

While cost-effectiveness is always a factor in screening programmes the presentation made the following points:

• The first cost effectiveness study reported that cervical screening (3-yearly) in HIV-negative women was estimated at costing USD$180,000 per life year saved. This compared to approximately USD$11,000 for anal cytology screening in HIV-positive men. [11]
• A more detailed and recent analysis from the same group estimated costs of USD $16,600 and $13,000 per Quality Adjusted Life Year saved (QALY) for annual or two-yearly screening in HIV-positive MSM. For HIV-negative MSM these costs were $34,800 and $15,100 respectively. [12]
• A recent UK study determined screening in HIV-positive men is estimated to cost UKP £39,400, and that this is apparently not cost-effective. [13]

While the BHIVA/BAASH guidelines have stated that the benefit of screening is ‘not yet proven’, a more positive set of guidelines from New York State has recommended screening in HIV-positive MSM, HIV-positive CIN/VIN, and HIV-positive people with a history of genital warts, although these recommendations are unlikely to be running in practice due to the demand this would place on anoscopy services.

For any screening to be effective it will be dependent on providing timely anoscopy follow-up for patient with abnormal cytology results.

COMMENT

Although the National Institute for Health Research (NIHR) has commissioned a new review to look at screening for anal cancer in the UK (currently in press), the degree to which HIV is addressed is unclear. [14]

This is difficult because an earlier review highlighted important reasons for making screening available to HIV-positive people and MSM. This earlier report was produced in 2003 and has not been reviewed since. [15]

The UK cost-utility study from Karnon et al is worrying for many reasons, especially if this is used as evidence against initiating a pilot screening programme. This paper has a complicated methodology, and some assumptions in their modeling are not fully explained.

• Mortality associated with anal cancer is based on data from 1996.
• All patients diagnosed with HIV before 1990 are assumed to have died by 2005.
• The disutility weighting for false-positive results is not clearly explained.
• It is odd to find worse outcomes from any screening programme, especially given the high relative risk in HIV-positive MSM. In this paper, no scenario produced better results from a screening programme compared to no screening.
• The paper uses triangular distribution and markedly different results could come from different distributional forms.
• In the explanation of calibration methodology, the rating scale used is not generally seen as most methodologically robust, and time trade off and standard gamble may be more appropriate.
• In the discussion, the authors recognise that they assumed higher HIV mortality than the US study, but they do not specify the rate used. They concede that this would reduce the effectiveness of screening, so this is an important figure to elaborate. They also do not state basis of expected mortality data, though it is used in several parts of the model, including reducing the effectiveness of screening in older MSM ‘as they have fewer QALYs to gain’.
• Finally, the paper makes a strange point about how MSM in the UK may not use a screening programme. This is supported by a reference to a study that reported that people get safer sex information from friends rather than clinics. The rationale for this is not clear. As people primarily use clinics for monitoring and treatment, accessing prevention information seems an inappropriate marker to use.

References

Unless stated otherwise, all references are to the Programme and abstracts from the 12th European AIDS Conference (EACS), 11-14 November 2009, Cologne.

1.    Bower M. Screening for non-AIDS malignancies: if and how? 12th EACS, 11-14 November, 2009, Cologne. Webcast:

http://www.multiwebcast.com/eacs/2009/12th/4149

2.     Bower M et al. British HIV Association guidelines for HIV-associated malignancies (2008).

http://www.bhiva.org/documents/Guidelines/Malignancy/080627MaligFinal.pdf

3.    Grulich AE et al. Incidence of cancers in people with HIV/AIDS compared with immunosuppressed transplant recipients: a meta-analysis. Lancet 2007; 370: 59-67. (7 July 2007). doi: 10.1016/S0140-6736(07)61050-2.

4.    Daling JR, Weiss NS, Hislop TG et al. Sexual practices, sexually transmitted diseases, and the incidence of anal cancer. N Engl J Med 1987, 317:973.

http://www.ncbi.nlm.nih.gov/pubmed/2821396

5.    Frisch et al. Human papillomavirus-associated cancers in patients with HIV and AIDS. Journal of the National Cancer Institute, Vol. 92, No. 18, 1500-1510, September 20, 2000. Free full text:

http://jnci.oxfordjournals.org/cgi/content/full/92/18/1500

6.     Diamond C et al. Increased incidence of squamous cell anal cancer among men with AIDS in the era of highly active antiretroviral therapy. Sex Transm Dis. 2005 May;32(5):314-20.

http://www.ncbi.nlm.nih.gov/pubmed/15849533

7.    Bower M et al Highly active antiretroviral therapy and the incidence of non-AIDS- defining cancers in people with HIV infection. J Clin Oncol 2009. 27(6);884-90.

http://www.ncbi.nlm.nih.gov/pubmed/19114688

8.    Biggar et al. Survival after cancer diagnosis in persons with AIDS. JAIDS 2005;39:293-299. Free full text:

http://pt.wkhealth.com/pt/re/jaids/abstract.00126334-200507010-00005.html

9.     Palefsky J et al. Progression of high-grade anal intraepithelial neoplasia to invasive anal cancer among HIV+ men who have sex with men. 16th CROI, 2009. Poster abstract 867.

http://www.retroconference.org/2009/Abstracts/36098.htm

10.    Palefsky J et al. Natural history and clinical management of anal human papillomavirus disease in men and women infected with HIV. Clin Inf Dis 2002;35:1127-1134.

http://www.journals.uchicago.edu/doi/abs/10.1086/344057

11.     Goldie SG et al. The clinical effectiveness and cost-effectiveness of screening for anal squamous intraepithelial lesions in homosexual and bisexual HIV-positive men. JAMA. 1999;281:1822-1829.     http://jama.ama-assn.org/cgi/content/full/281/19/1822

12.    Goldie at al. Cost-effectiveness of screening for anal squamous intraepithelial lesions and anal cancer in human immunodeficiency virus-negative homosexual and bisexual men. Am J Med 2000; 108(8): 634-41. (1 June 2000).

http://www.ncbi.nlm.nih.gov/pubmed/10856411

13.    Karnon J et al. Cost-utility analysis of screening high-risk groups for anal cancer. Journal of Public Health 2008 30(3):293-304

http://jpubhealth.oxfordjournals.org/cgi/content/full/30/3/293

14.    Czoski-Murray C. What are the pros and cons of screening high risk populations for anal cancer? NIHR NTA Study.

http://www.hta.ac.uk/news/newsitem120606.shtml

http://www.hta.ac.uk/project/1489.asp

15.    Structured review for the UK National Screening Committee – appraising the viability, effectiveness and appropriateness of an anal cancer screening programme (2003). Direct download:

http://www.library.nhs.uk/SpecialistLibrarySearch/Download.aspx?resID=60464

A tiny pilot for a Phase 2 study in treatment naïve patients was stopped prematurely, concluding that once-daily darunavir/r was not sufficiently potent as initial treatment in treatment naïve patients for the study to continue.

Seven patients (with baseline viral load <100,000 copies/mL and CD4 counts >100 cells/μL and no evidence of drug resistance) were started on open-label darunavir/r monotherapy. At week 4, all patients had >1 log drop in viral load and by week 8, viral load was <400 copies/mL in 4/7. However, the trial was stopped as 5/7 patients had inadequate viral responses (together with the high level of screening failures – 38/45 screened – which would limit enrollment for the larger planned study).

All seven patients achieved viral loads <50 copies/mL following intensification with nucleosides. CD4 responses at week 12 were +167 cells/μL. No grade 3-4 clinical or laboratory events were reported. No darunavir-associated mutations were seen in the two patients with genotype results.

COMMENT

Although these results were disappointing as initial therapy, an analysis of the MONET study that randomised people with undetectable viral load (<50 copies/mL) on any HAART regimen to either darunavir/r as monotherapy or plus dual RTIs, reported non-inferiority (difference = –1.6; 95%CI –10.1 t0 +6.8%) in terms of the percentage of people in each group with <50 copies/mL at week 48 (86.2% vs 87.8% respectively). [2]

These results were supported by other analyses, which is important for the continued use of darunavir/r in the currently enrolling MRC PIVOT study of PI-monotherapy maintenance therapy. [3]

References:

1.    Patterson P et al. A Phase II, open-label trial in treatment-naïve. HIV-1-infected subjects who received DRV/RTV as induction monotherapy. 12th EACS, 11-14 November 2009, Cologne. Abstract PS4/4.

2.    Ripamonti D et al. Non-inferior efficacy shown across different efficacy endpoints in the MONET trial of darunavr/ritonaivr (DRV/r) monotherapy. 12th EACS, 11-14 November 2009, Cologne. Abstract PS 4/1.

3.    PIVOT: Protease Inhibitor monotherapy Versus Ongoing Triple-therapy in the long-term management of HIV infection.

http://www.ctu.mrc.ac.uk/research_areas/study_details.aspx?s=55

A cross-sectional study from two large French hospitals presented at EACS was important for confirming that central fat accumulation (CFA), one of the symptoms associated with HIV-related lipodystrophy, remains a significant side effect, even for patients who have started treatment recently.

Isabelle Poizot-Martin and colleagues used waist circumference as a surrogate marker of CFA in 838 HIV-positive patients (71% male, 29% female) who started combination antiretroviral therapy (cART) before (Group 1, n=723) or after January 2005 (Group 2, n=115).
CFA was defined as >102/88 cms (using NCEP ATPIII guidelines) or >94/80 cms (using IDF classification), for men/women respectively.

Median age (years) was 46 in Group 1 and 44 in Group 2 (p=0.004). Median CD4 count was 523 and 472 cells/mm3, respectively (p=0.06) and viral load was < 40 copies/mL in 84% of patients in each group. Exposure to cART was 11.6 vs 2.1 years for Group 1 and 2 respectively.

CFA was reported in significantly higher rates for women compared to men in both groups, but also at higher rates in women who started treatment after 2005 compared to women who started treatment earlier, as detailed in Table 1.

Table 1: Percentages of patients with CFA diagnosed by waist circumference

* p=0.028 ** p=0.013 (between group comparisons)

While there were significant differences in use of different drugs in Group 1 compared to Groups 2 (mainly a higher use of triple-nucleoside regimens: by 11 vs 2% of patients), there were no significant differences by sex, particularly for Group 2.

COMMENT

While further associations are limited in a single cross-sectional dataset, the conclusion that CFA remains highly prevalent in patients who started treatment recently, is important.

The different rates of CFA in women compared to men had been previously reported and clearly warrant further study.
The results support the importance for every new antiretroviral to include prospective monitoring of body fat changes within Phase 3 studies. It is difficult to understand how any new drug could be approved without data on the impact it has on lipodystrophy and body fat changes.

Ref: Poizot-Martin I et al. Abdominal adiposity remains highly prevalent in French HIV-infected patients having initiated antiretroviral therapy after 2005. 12th EACS. 11-14 November 2009, Cologne. Abstract PS11/1.

A small randomised placebo-controlled study (ANRS 120) showed that alendronate therapy (70mg once-weekly) significantly increased bone mineral density (BMD) at the osteoporotic site after 96 weeks. All patients also received  calcium carbonate 500mg and vitamin D 400 units daily. [1]

Rozenberg and colleagues randomised 44 patients (n=20 alendronate; n=24 placebo)) with T-scores less than –2.5 at lumbar spine and/or total hip assessed by DXA. Mean age at baseline was 45 years, CD4 count was 422 cells/mm3 and 84% had viral load <400 copies/mL. Only two women were in this study.

At week 96, BMD increased at the osteoporosis site by 7.1% vs 1.0% in the alendronate and placebo groups respectively [mean difference 6.1% 95%CI 2.8 to 9.3%; p=0.003]. BDM increased by >2.5% in 86% vs 40% in each group respectively. A greater number of adverse events were reported in the placebo group (13 vs 6).

The authors concluded that alendronate improved BMD in HIV-positive people using antiretroviral treatment who were diagnosed with osteoporosis.

COMMENT

While this study confirmed results from an earlier 48-week randomised trial [2], and suggested additional benefits from longer treatment, the earlier study should have been sufficient not to require a placebo for any patients with diagnosed osteoporosis.
Aledronate is already included in HIV guidelines that discuss the management of osteoporosis.

However, until DXA screening is included in routine management, the majority of HIV-positive patients with low bone mineral density are unlikely to have their osteoporosis diagnosed unless it becomes symptomatic (ie post-fracture).

The recent EACS monitoring guidelines (November 2009) included the recommendation to use the FRAX online calculator to screen HIV-positive patients.

References

1.    Rozenberg S et al. Effect of alendronate on HIV-related osteoporosis: a randomised, double-blind, placebo-controlled trial (ANRS 120). 12th EACS, 11-14 November 2009, Cologne. Abstract PS5/4.

2.    McComsey G et al. Alendronate with calcium and vitamin D supplementation is superior to calcium and vitamin D alone in the management of decreased bone mineral density in HIV-infected patients: Results of ACTG 5163. 14th CROI, 2007. Oral abstract 42.

http://www.retroconference.org/2007/Abstracts/28458.htm

TMC278 (ripivirine) is a novel NNRTI currently under investigation. The embryo-foetal toxicity was evaluated in rats and rabbits.
In this study, pregnant Sprague-Dawley rats (by oral gavage) and New Zealand white rabbits (by oral dosing) received doses of TMC278 during the period of organogenesis (days 6-17 and 6-19 in rats and rabbits respectively).
Doses observed were: 400, 120 and 40 mg/kg/day in rats; and 20, 10 and 5 mg/kg/day in rabbits. Both animal models had a control group.

The investigators reported moderate maternal toxicity (reduced food consumption, and body weight gain, and increased thyroid weight) in rats at the two higher doses. In rabbits they did not observe any maternal toxicity.

They reported no teratogenetic effect in either animal and there was no effect of treatment on pregnancy parameters.
In rats in the two higher dose groups they observed an increase in incidence of dilated renal pelvis (visceral variant) 120 mg/kg/day, p<0.05 and 400 mg/kg/day, p<0.01 compared to the control group. This was the only finding on embryo-foetal development in rats.
The maternal and embryo-foetal development no observable adverse effect level (NOAEL), was 40 mg/kg/day, associated with a maternal AUC0-24h of 37 ug.h/mL.

With rabbits, the only finding was a slight increase in the incidence of minor variations of the left subclavian artery, p<0.05 and hypoplastic interparietal bone, p<0.05 compared to the controls in the group receiving 20 mg/kg/day.

The maternal toxicity and embryo/foetal NOAELs were 20 mg/kg/day and 10 mg/kg/day, respectively, which were associated with maternal AUC0-24h of 232 ug.h/mL and 170 ug.h/mL.

The investigators concluded that TMC278 did not show teratogenic potential in rat and rabbit models at drug exposures 13-80 times higher than those in HIV-positive patients receiving 25 mg/qd at steady state (TMC278-C204 Study AUC0-24h was 2.8 ug.h/mL).
Based on this data they suggest that further studies in women of child bearing potential are warranted.

Ref: Desmidt M et al. Absence of a teratogenic potential from a novel next-generation NNRTI, TMC278. 12tth EACS. 11-14 November, 2009. Cologne. Abstract PE7.1/4.

A pharmacokinetic (PK) and safety study of etravirine (ETR) was conducted in five pregnant women receiving this next generation NNRTI through compassionate use during the clinical development programme.

PK assessments were performed in the third trimester and/or time of delivery. Samples were collected 1, 3, 6 and 12 hours post dose. Cord blood samples were obtained where possible. Plasma concentrations were determined using high performance LC-MS/MS (LLOQ 2ng/mL).

A non-compartmental model was used for the PK analysis and compared with population PK data from earlier trials. The investigators noted that in these trials (DUET-1 and DUET-2) PK parameters did not differ significantly between men and women.
In this study three women received ETR throughout pregnancy and two only in the third trimester.

The investigators reported comparable values in all five women to historical controls. See Table 1.

Table 1: PK parameters of ETR in third trimester

AUC=Area under the curve; C=concentration; T=time
* AUC 6h

Three of the women had caesarean sections (one preterm due to twins) and the remainder vaginal deliveries.

The babies were all healthy. One was born with a polyotia but was otherwise normal. No other abnormalities were reported.

The investigators concluded that ETR PK in five pregnant women is comparable to that in non-pregnant adults, which suggests that no dose adjustment is needed. In this small study ETR did not have an effect on foetal toxicity.

ETR in pregnant women will be evaluated further in an ongoing trial investigating PK parameters of darunavir/r and ETR during the second and third trimesters and up to 12 weeks postpartum. [2]

COMMENT

The importance of conducting these studies and reporting even no effect must be stressed as guidance in this area is vague for many antiretrovirals.

References

1.    Izurieta P et al. Safety and pharmacokinetics of etravirine in pregnant HIV-infected women.  12th EACS. Cologne. 11-14 November 2009.  Abstract PE4.1/6.

2.    A study to assess the pharmacokinetics (blood levels) of TMC114 (darunavir) taken with TMC114r (ritonavir), and TMC125 (etravirine) in HIV-1 infected pregnant women

http://clinicaltrials.gov/ct2/show/NCT00855335

An open label trial conducted by Crauwels and colleagues evaluated the pharmacokinetic (PK) interaction between TMC278 and norethindrone plus ethinylestradiol.

In this analysis, 18 HIV-negative volunteers received 1mg norethindrone plus ethinylestradiol 35ug (combined oral contraceptive pill, Ovysmen) once a day for three sequential 21-day cycles spaced with with 7-day intervals. TMC278 was co-administered for the first 15 days of the third cycle at a once daily dose of 25 mg. TMC278 and Ovysmen were taken within 10 minutes after breakfast.

At day 15 of the second and third cycles 24 PK profiles of norethindrone, ethinylestradiol and TMC278 were obtained. Plasma samples were analysed using validated LC-MS/MS methods, with a lower limit of quantification of 1.0 ng/mL for TMC278, 50.0 pg/mL for norethindrone and 2.0 pg/mL for ethinylestradiol. Serum levels of progesterone luteinising hormone (LH) and follicle-stimulating hormone (FSH) were determined on days 1 and 14 of the second and third cycles.

PK parameters were calculated using non-compartmental analysis. Statistical analysis compared the test treatment, Ovysmen+TMC278 to the reference, Ovysmen alone.

The women in the study were a median age of 26 years, weight 69.5kg and BMI 24.6. The majority (67%) were white.

The investigators reported no effect on norethindrone PK when co-administered with TMC278. With ethinylestriol, neither the Cmin, nor the AUC24h were affected and Cmax increased by 17% in the presence of TMC278. This increase is not expected to have a clinically relevant effect. See Table 1 for results of PK parameter ratios for norethindrone and ethinylestriol in the presence of TMC278.

Table 1: PK parameter ratios for norethindrone and ethinylestriol in the presence of TMC278

Steady state PK parameters of TMC278 25mg/QD in the presence of noretindrone and ethinylestriol were comparable to values observed in previous trials of TMC278 alone. TMC278 25mg/QD had no clinically relevant effect on FSH, LH or progesterone serum levels in the presence of noretindrone and ethinylestriol.

The investigators concluded that the contraceptive efficacy of 1mg norethindrone plus ethinylestradiol 35ug is expected to be maintained in the presence of TMC278 25mg/qd without dose modifications.

Ref: Crauwels et al. Pharmacokinetic interaction study between TMC278 an NNRTI, and the contraceptives northindrone plus ethinylesradiol. Abstract PE4.3/3

Several studies looked at the impact of gender on different aspects of antiretroviral treatment.

UK CHIC Study

The UK Collaborative HIV Cohort (CHIC) Study analysed the impact of starting HAART among heterosexuals initiating treatment between 1 January 1998 and 1 January 2007 at <350 CD4cells/mm3 and viral load (VL) >500copies/mL. [1]

The analyses used logistic and Cox regression models adjusted for age, ethnicity, calendar year, initial ART, previous AIDS and pre-ART CD4/VL. Sensitivity analyses were performed in which women who initiated HAART for the first time during pregnancy or became pregnant in their first year of HAART were excluded.

Of 3666 eligible patients for this study, 1487 (40.6%) were male and 2179 (59.4%) female. The investigators reported that men who started therapy in this group were significantly older than women, median 38 vs 33 years; had lower CD4 counts, 122 vs 160 cells/mm3 and higher viral load, 5.0 vs 4.7 log copies/mL, both p=0.0001.

Men were less likely than women to start with a nevirapine-based regimen (18.4 vs 34.7%).

They found no significant differences in initial viral load response, adjOR men vs women 0.95 (95% CI 0.87-1.03), p=0.19; or time to rebound, adjRH, 1.17 (0.93-1.47), p=0.19. However, men were less likely to stop a drug in their regimen, for reasons other than viral failure. (In this analysis, 79.4% of the group experienced initial viral load response (defined as <50 copies/mL) and 19.2% experienced viral rebound (two consecutive viral load >500 copies/mL).

CD4 counts increased across the cohort by a mean of 112 and 156 cells/mm3 at 6 and 12 months respectively. Men had significantly lower increases than women at both time points by 14.6 (p=0.005) and 12.1 (p=0.05) cells/mm3 respectively.

The overall findings remained unchanged when the investigators excluded pregnant women from the analysis. Of 2179 women included, 273 (12.5%) started HAART in pregnancy and 40 (1.8%) became pregnant within a year of starting.

The investigators noted that some gender differences became more pronounced and statistically significant in this sensitivity analysis.
Men were more likely to have viral rebound than women, RH 1.33 (1.04-1.71), p=0.02, but they continued to be less likely to discontinue treatment for reasons other than virological failure, RH 0.76 (0.65-0.88), p=0.0002. CD4 increases remained lower in men by 11.1 cells/mm3, p=0.03; and 10.9 cells/mm3, p=0.07, at 6 and 12 months respectively.

The investigators concluded that virological outcome was similar between men and women in this cohort. They suggested that the higher CD4 increase on treatment may be explained by their higher nadir and baseline CD4 count.

They also suggested that the finding that women were more likely to discontinue their treatment for reasons other than viral failure may be associated with a higher incidence of adverse events such as CNS toxicities associated with efavirenz. They wrote: “Further investigation into the reasons for discontinuation may shed light on the different CD4 responses and improve ART sequencing options for men and women.”

STAR and STELLA cohorts

STAR and STELLA are two German prospective, multicentre cohort studies for antiretroviral naïve patients starting a lopinavir/r-based regimens.

A 48-week analysis comparing treatment outcomes, adverse events and self reported symptom distress, between men and women, was performed. [2]

Of a study population including 1136 patients, 984 were men and 172 were women. Men were older (median 41 vs 38 years, p=0.001), had higher median viral load (5.1 vs 4.9 log copies/mL, p<0.001), a lower CD4 percentage (12% vs 14%) and similar absolute CD4 counts (194 vs 214 cells/mm3).

At 48 weeks in ITT analysis, 308/467 (66%) men and 50/74 (68%) women had viral load <50 copies/mL. Median increases in CD4 count were 218 vs 198 cells/mm3 in men and women respectively.

Using the ASDM self-reported questionnaire to look at symptom distress revealed similar scores in men and women, 11.0 vs 12.5 respectively at baseline. Scores in both groups decreased significantly at week 48, by 3 and 2 in men and women respectively, both p<0.01.

Baseline symptoms of adverse events of any grade were documented in 16% men and 10% women, p=0.05. At 48 weeks 26% men and 15% women reported adverse events, p=0.04.

A similar proportion of men (7%) and women (5%) discontinued lopinavir/r for toxicities and 1% and 2% due to virological failure.

In Kaplan Meier analysis the investigators found the probability of remaining on treatment was similar, (76% vs 78%) in men vs women.

They reported no differences in virological and immunological outcomes and similar rates of discontinuation due to adverse events between men and women initiating lopinavir/r based regimens.

CASTLE study

The CASTLE study was a multinational noninferiority study comparing atazanavir/r- to lopinavir/r- based regimens both with background tenofovir and emtritabine in 883 patients.

An analysis was performed at 96 weeks to look at virological, immunological and safety profiles by gender. [3]

Overall 277/883 (31%) patients in this study were women. Baseline characteristics were similar in men and women in this study.
As previously reported, once-daily treatment with atazanavir/r was noninferior to twice-daily lopinavir/r, 74% of patients receiving atazanavir/r and 68% of patients receiving lopininavir/r achieved VL <50 copies/mL at week 96; difference estimate 6.1% (95% CI, 0.3-12%, p<0.05).

Discontinuation rates were higher for women than men in both treatment groups: 21% vs 14% and 29% vs 18%, women vs men, in patients receiving atazanavir/r and lopinavir/r, respectively.

In ITT analysis, more men than women had VL <50 copies/mL at 96 weeks: 77% vs 67% and 71% vs 63%, men vs women, in patients receiving atazanavir/r and lopinavir/r respectively. These differences were not observed in on treatment analysis.
Mean CD4 cell increases from baseline, rates of adverse events and lipid profiles were similar between genders. GI adverse events and lipid profiles were lower in both men and women receiving atazanavir/r than lopinavir/r.

The investigators wrote: “Consistent with other ARV clinical trials, gender differences in treatment efficacy were primarily due to higher discontinuation rates in women.”

GRACE

GRACE (Gender, Race and Clinical Experience) was a multicentre open label phase 2b study to access the safety and efficacy of duranavir/r plus optimised background regimen.

A post hoc analysis was conducted to investigate factors correlated with adherence in GRACE. [4]

In this study the mean age of patients was 42.9 years, 66.9% patients were women, and 61.5% and 22.4% of the total population were black and Hispanic respectively. At baseline women were younger on average and tended to have less advance disease and be less treatment experienced than men.

The virologic response (VL<50 copies/mL) at week 48 was 53.4% in ITT analysis. See Table 1 for response rates by sex and race.

Table 1: Virologic response <50 c/mL at week 48 by sex and race, n (%)

The response rate in patients with >95% adherence was 63.1% compared to only 34.7% in those with <95% adherence.
In multivariate analysis the investigators found no significant differences between sexes or across race in GRACE. More IAS/USA major protease resistance associated mutations, participation at a non-academic site, fewer NRTIs in the OBR, being a non-smoker and having a CV medical history were predictive of >95% adherence.

References

All references are abstracts from the 12th European AIDS Conference (EACS), 11-14 November 2009, Cologne.

1.     Barber T et al. Outcomes of first line highly active antiretroviral therapy (HAART) among men and women in the UK CHIC study. Abstract

2.     Koegl C et al. No subjective or objective gender differences in ART-naïve patients initiating a lopinavir/ritonavir-based regimen. 48 week data from the German STAR and STELLA cohorts. Abstract PE 7.9/19.

3.     Johnson M et al. Gender based differences in antiretroviral-naïve patients treated with ritonavir-boosted protease inhibitors: results from the CASTLE study through 96 weeks. Abstract PE7.3/8

4.     Squires K et al. Rates and predictors of adherence in treatment experienced women and men in GRACE (Gender, Race And Clinical Experience). Abstract PE10.1/2.

Affordable protease inhibitors in suitable formulations for children are urgently needed.

De Kanter and colleagues from the University Nijmegan, the Netherlands, showed pharmacokinetic (PK) data from a phase I, open-label crossover study to evaluate two generic paediatric formulations of lopinavir/ritonavir developed by Cipla Pharmaceuticals (Lopimune tablets and granules 100/25mg). This was a pilot study designed to exclude large (>40%) differences in the exposure to lopinavir achieved using the generic formulations compared to the originator product (Kaletra).

Twelve HIV-negative adult volunteers were randomised to receive the following sequences of regimen ABC, ACB, BCA, BAC, CAB, CBA: A=Kaletra tablets, B=Lopimune granules and C=Lopimune paediatric tablets. They were given single doses of medication (400mg lopinavir) on an empty stomach at one-week intervals and a 32-hour PK curve was recorded. A 32- hour PK curve was also recorded for 5/12 volunteers after receiving lopinavir granules and Kaletra oral formulation both with food.

The volunteers were a median age 24 (range 21-55) years, height 1.79 (range 1.63-1.95) meters and weight 72 (range 51-87) kg. One third of the group were women.

The investigators found the median lopinavir AUC0-t was 71.8 h.mg/L (IQR 48.7-93.5) with Kaletra tablets (A), and 38.7 h.mg/L (IQR 28.7-52.2) and 58.7 h.mg/L (IQR 42.5-79.4) with Lopimune granules (B) and Lopimune tablets (C) respectively. With Kaletra tablets as a reference these differences were statically significant, B vs A, p=0.003 and C vs A, 0.015. Cmax median values were 7.2 mg/L (IQR 5.8-8.3), 4.6 mg/L (IQR 4.1-5.2) and 6.5mg/L (IQR 5.0-7.1); B vs A, p=0.003 and C vs A, p= 0.012.

The investigators also noted lower ritonavir concentrations with the Lopimune formulations compared to Kaletra.

A sub-group of volunteers received Lopimune granules (n=5) and Kaletra oral solution (n=4) with food. In this comparison, the median lopinavir AUC0-t was 62.1 h.mg/L (IQR 43.8-126.3) with Kaletra tablets, and 58.5 (IQR 55.4-77.6) and 49.6 h.mg/L (IQR 39.1-58.1).
Cmax median values were 7.2 mg/L (IQR 4.6-9.1), 6.4 mg/L (IQR 5.5-7.6) and 5.2mg/L (IQR 4.3-5.7).

The investigators concluded that it is possible to exclude large differences in PK parameters for the Lopimune paediatric tablets, compared to Kaletra, when received on an empty stomach. Large differences can also be excluded for the Lopimune granules when these are received with food.

They added that, based on these results, it was acceptable to start PK and dose finding trials of the Lopimune paediatric tablets and granules even though the Cipla bioequivalence study was not yet complete.

COMMENT

This study did not test the effect of different compositions of meals on the absorption of LPV/r. They used a standardised “normal” European/Dutch breakfast, to see if the absorption would be better with food than without, as this is the case with the absorption of lopinavir from Kaltera oral solution. The absorption from the granules might be dependent on the amount of fat in the meal as is stated in the Summary of Product Characteristics.

Since this small study, the Cipla formulation has changed and has been slightly refined, so there is an ongoing bioequivlance study. CHAPAS 2, which will look at these products in children, is waiting on these results before it begins (probably around March). CHAPAS 2 will be able to investigate absorption among breastfeeding  children and also those who are malnourished.

Ref: de Kanter et al. The pharmacokinetics of two generic co-formulations of lopinavir/ritonavir for HIV-infected children: a pilot study of pediatric lopimune formulations vs the branded product in healthy volunteers. 12th EACS, Cologne, November 11-14, 2009. Abstract PE15.2/1.

This report summarises drug interaction and pharmacology studies presented at this recent meeting. Unless stated otherwise, all references are to the 12th European AIDS Conference (EACS), 11-14 November 2009, Cologne.

Raltegravir and famotidine or omeprazole

The effect of famotidine (20 mg single dose 2 h before raltegravir) or omeprazole (20 mg once-daily for 5 days, 2 h before raltegravir) was studied in 18 HIV-positive subjects stable on raltegravir (400 mg twice-daily) regimens.   Coadministration of famotidine increased raltegravir AUC, Cmax and Ctrough by 45%, 60% and 6% respectively.  Omeprazole increased raltegravir AUC, Cmax and Ctrough by 39%, 51% and 24%, respectively.  The increases were not clinically significant and raltegravir may be coadministered with famotidine or omeprazole without dose adjustment.

COMMENT

This effect is less than previously seen in healthy volunteers.

Ref: Rhame F et al. Effects of famotidine and omeprazole on raltegravir pharmacokinetics in HIV‐infected persons.  12th EACS, 11-14 November 2009, Cologne. Abstract PE4.1/1.

P450 and P‐gp activities in HIV-positive and HIV-negative subjects

The activity of CYP3A, 2D6 and P‐gp were investigated in 30 HIV-positive, treatment naïve patients and 12 HIV-negative controls.
Subjects were given a “phenotyping cocktail” containing midazolam (1.5mg, intestinal and hepatic CYP3A), dextromethorphan (30 mg, CYP2D6), digoxin (0.5 mg, P‐gp) and IV midazolam (1.0mg, hepatic CYP3A).

The activities of CYP3A, CYP2D6 and P‐gp were lower in the HIV-positive subjects, but with the exception of CYP3A, the differences were small. Total CYP3A activity was 0.493‐fold lower in HIV-positive subjects than in HIV-negative controls.

Within group variability was greater than between group variability, making it unlikely that dose adaptations based on infection status would be useful.

Ref: Jetter A et al. Are there differences between healthy volunteers and HIV‐infected patients in the activities of CYP3A, CYP2D6 and P‐glycoprotein. 12th EACS, 11-14 November 2009, Cologne.  Abstract PE4.1/9.

MVC and CYP450 inhibitors or inducers

Maraviroc trough concentrations were determined in HIV-positive subjects receiving maraviroc in combination with CYP450 inhibitors or inducers.

Median maraviroc trough concentrations were 83 ng/mL, with 24% being below target (50 ng/mL) in subjects receiving maraviroc 150 mg twice daily with a boosted PI (not TPV or APV).  In subjects receiving maraviroc 300 mg twice daily with a boosted PI, the median trough concentration was 264 ng/ml and 9% were below target.

When maraviroc was administered as 300 mg twice daily without a boosted PI or NNRTI, median trough concentrations were 47 ng/mL and 55% were below target. Coadministration of maraviroc 600 mg twice daily with etravirine resulted in median trough concentrations of 77 ng/mL, of which 19% were below target.

COMMENT

There is data suggesting that the average concentrations (Cavg) may be a better parameter to correlate with viral response.

Ref: Sari‐Chaaf Zet al. Maraviroc boosted (or not) by ritonavir? Pharmacokinetic results from routine therapeutic drug monitoring. 12th EACS, 11-14 November 2009, Cologne. Abstract PE4.2/1.

Abacavir and darunavir/r or raltegravir

This study investigated the steady‐state plasma pharmacokinetics of abacavir (600 mg once daily) when co‐administered with darunavir/ritonavir (900/100 mg once daily) or raltegravir (400 mg twice daily) to 19 HIV-positive subjects.

Abacavir AUC, Cmax and Cmin decreased by 27%, 22% and 38%, respectively in the presence of darunavir/ritonavir.  When coadministered with raltegravir, the AUC and Cmax of abacavir increased by 3% and 6%, respectively; Cmin decreased by 17%. It is important to relate the change in plasma abacavir exposure to the active intracellular carbovir triphosphate and a study is in progress.

Ref: Jackson A et al. Pharmacokinetics (PK) of plasma abacavir (ABC) in the absence and in the presence of darunavir/ritonavir (DRV/r) or raltegravir (RAL) in HIV‐infected subjects. 12th EACS, 11-14 November 2009, Cologne. Abstract PE4.3/2.

TMC278 and oral contraceptives

The pharmacokinetic interaction between TMC278 (25mg once daily) and an oral contraceptive containing norethindrone/ethinylestradiol (1/0.035mg) was studied in 18 HIV-negative females.  Norethindrone pharmacokinetics were unaffected by TMC278 (11% decrease in AUC, 6% decrease in Cmax, 1% decrease in Cmin).

There was no statistically significant change in ethinylestradiol AUC (14% increase) or Cmin (9% increase), but Cmax increased by 17%, however, this is not expected to be clinically significant.  Pharmacokinetics of TMC278 were within the expected range.  There was no marked effect on FSH, LH and progesterone serum levels.

TMC278 and oral contraceptives containing norethindrone/ethinylestradiol can be coadministered without dose modifications.

Ref: Crauwels H et al. Pharmacokinetic interaction study between TMC278, a next‐generation nonnucleoside reverse  transcriptase inhibitor (NNRTI), and the contraceptives norethindrone plus ethinylestradiol. 12th EACS, 11-14 November 2009, Cologne. Abstract PE4.3/3.

Darunavir and raltegravir interaction

Darunavir trough concentrations were determined in 117 samples from 55 HIV-positive patients receiving darunavir containing regimens with either a NRTI or raltegravir.

Mean (± sd) darunavir concentrations were higher in the NRTI subjects than in the raltegravir subjects (4.20 ± 2.35 vs 2.63 ± 84 mg/L).  However, the proportion of subjects with undetectable viral loads (<50 copies/mL) was higher in the raltegravir group than in the NRTI group.

After adjusting for time from last drug intake and concomitant drugs, a multivariate linear regression model confirmed raltegravir to be independently related to lower darunavir concentrations.

The mechanism of this unexpected interaction remains to be determined, but it does not appear to be virologically significant.

COMMENT

This data is consistent with a previous report from Garvey et al presentated at the IAS meeting in Cape Town  (IAS 2009, LBPEB08).  The absolute darunavir concentrations in the Fabbiani study are higher than previously reported.

Ref: Fabbiani M et al. Unexpected drug interaction between darunavir and raltegravir. 12th EACS, 11-14 November 2009, Cologne. Abstract PE4.3/4.

Raltegravir and unboosted atazanavir

The steady state pharmacokinetics of raltegravir (400 mg twice daily) and unboosted atazanavir (300 mg twice daily) were determined in 22 HIV-positive subjects who switched from their current regimen.

Atazanavir geometric mean AUC, Cmax and Ctrough were 14454 ng.h/ml, 2275 ng/ml and 419 ng/mL respectively. Raltegravir geometric mean AUC, Cmax and Ctrough were 7112 ng.h/ml, 1680 ng/ml and 62 ng/ml.  Three subjects (14%) had atazanavir trough concentrations below 100 ng/ml.

At the time of switch, 79% subjects had undetectable viral load, but at week 24, all subjects had undetectable viral loads.

COMMENT

These data are generally consistent with Zhu et al (CROI 2009, abstract 696).

Ref: Ripamonti D et al. Steady‐state pharmacokinetics, efficacy, safety and tolerability of dual regimen with atazanavir  (300mg  bid)  plus  raltegravir  (400mg  bid)  in  HIV‐1‐infected  patients:  24‐week  results  (CARDS  study). 12th EACS, 11-14 November 2009, Cologne. Abstract LBPE4.3/5.

Nevirapine and efavirenz concentrations, during and after stopping rifampicin

Concentrations (12 h post dose) of nevirapine (400 mg/day, n=71) and efavirenz (600 mg/day, n=71) were determined at 6 and 12 weeks after starting rifampicin and then after rifampicin had been discontinued.  Mean ±SD concentrations for nevirapine at weeks 6, 12 and after discontinuation were 5.6 ± 3.6, 5.5 ± 2.6 and 6.7 ± 3.5 mg/L, respectively.

Efavirenz concentrations at the same time points were 4.5 ± 4.3, 3.8 ± 3.5 and 3.5 ± 2.7 mg/L, respectively.  Patients on efavirenz showed greater inter‐patient variability whilst receiving rifampicin than patients on nevirapine.

Ref: Manosuthi W et al. Serial monitoring of drug concentrations while on and off rifampicin between standard doses of nevirapine‐based and efavirenz‐based antiretroviral regimens. 12th EACS, 11-14 November 2009, Cologne. Abstract PE4.6/1.

Traditional medicine use in Uganda

The use of African herbal medicines in HIV-positive subjects receiving antiretroviral therapy was assessed in four districts of Uganda by interviewing traditional medicine practitioners (n=25) and HIV-positive subjects (n=44).

Over 100 plant species were identified, with approximately 80% of preparations being taken orally.

Multi‐plant preparations were common in 75% districts, with mono‐plant preparations being predominant in one district.  Plant parts frequently used were leaves (33%), stem bark (23%) and root bark (18%). The priority plants identified included Aloe sp, Erythina abyssinica, Sarcocephalus latifolius, Psorospermum febrifugum, Mangifera indica, Warburgia salutaris and Albizia coriaria.

COMMENT

The widespread use of traditional medicines with largely unknown effects on drug disposition indicates the need for studies in this area.

Ref: Lamorde M et al. Traditional medicine practices in the context of HIV in Uganda. 12th EACS, 11-14 November 2009, Cologne. Abstract PE19.9/1.

We continue our reports from the 11th International Workshop on Adverse Drug Reactions 
and Co-morbidities in HIV
, held this year from 26–28 October 2009 in Philadelphia, with this report on important new research for hepatitis C treatment.

• The HCV pipeline – efficacy and side effects of compounds in Phase 3 studies

The meeting organisers make nearly all oral presentations to be available as free access webcasts. The oral plenary lectures at the meeting are of a consistently high standard, often inviting experts from outside the HIV field to provide an overview on newly emerging issues relating to long-term HIV management.

http://lipo09.events-register.com

Christoph Sarrazin from Goethe Hospital, Frankfurt presented an update on recent research relating to HCV treatment. [1]

The context for the importance of new HCV treatment for use in coinfection, is the urgent need for more effective therapies; less than 50% of currently treated patients achieve a sustained virological response (SVR), with up to 25% being non-responders and another 25% relapsing. Many more patients are excluded from treatment because of co-morbidities, contraindications to treatment or an individual choice to defer treatment based on the side effect profile of pegylated interferon plus ribavirin. These factors all underline the need for better treatment for HCV.

As with HIV, a broad understanding of the HCV lifecyle has provided several targets for treatment, outlined in Table 1. Most antiviral pipeline compounds are either protease (NS3/4A), polymerase (NS5B nucleosides and non-nucleoside) or NS5A inhibitors, or they interact with host proteins or work via unknown mechanisms (silibinin, nitazoxanide etc). However, the development of many compounds have been stopped due to poor efficacy or tolerability, and most of those remaining are only in Phase 1 or 2 studies. Only two HCV antivirals are currently in Phase III studies, both of them protease inhibitors: telaprevir (VX-950) and boceprevir (SCH-503034).

Table 1: HCV lifecycle and target for drugs in pipeline

Telaprevir and boceprevir were both highly active in early studies in HCV monoinfected, treatment-naïve patients with HCV genotype-1, producing rapid viral load drops (approximately 4 logs and 2 logs,respectively) after 3 days  of monotherapy. [2, 3]

However, only a minority of patients had continued declines over 14 days. As with HIV monotherapy, a single hepatitis C antiviral is not sufficiently potent to eliminate the virus or even maintain viral suppression. The rapid emergence of resistance around the active binding site (at codons V36, T54, R155 and A156) leads to reduced antiviral activity. The long-term clinical implications of HCV antiviral drug resistance are unknown.

When telaprevir was combined with PEG-IFN as dual therapy in a Phase 1 study, reductions of up to 7 logs were maintained for all patients at day 14, but the PROVE-2 Phase 2 trial showed that ribavirin also need to be included for sustained and durable responses. Notably, the triple combination reduced both duration of treatment (from 48 down to 12 weeks) and the risk of viral breakthrough to 3%. See Table 2. [4]

Table 2: Percentages of pts with undetectable HCV PCR (<10 IU/mL) in the PROVE study

Roche’s INFORM-1 study provided an indication of the potential to combine new HCV drugs without the PEG-IFN plus ribavirin.  INFORM-1 is a proof-of-principle study using a dual protease/polymerase inhibitor combination of R7227 plus R7128, presented at EASL in 2009 (5).

Treatment-naïve patients in the higher dose arms had HCV viral load declines of -5 logs, with up to 30% achieving undetectable levels, and with no evidence of early viral breakthrough. At the 2009 AASLD meeting, INFORM-1 data from treatment experienced patients (relapsers, non-responders and null responders) were presented; the median HCV RNA drop was  >4 log. [6]

These were exciting 14 day results, but results from longer-term results on efficacy, resistance and tolerability are now awaited. BMS has initiated a Phase 2 study combining 790052, an NS5a inhibitor plus BMS-650032,an HCV protease inhibitor, in null responders.
These newest compounds are important for their activity against HCV genotype-1, currently the least responsive to PEG-IFN plus ribavirin. Both boceprevir and telapravir, however, have reduced activity against HCV genotpye-2 and virtually no activity against genotypes 3 and 4.

Adding boceprevir to the current standard of care in treatment-naïve patients with genotpye-1 increased SVR response rates from approximately 40% to 56% at week 28 and to 75% at week 48 for the triple combination. [7]

Similar results were seen for telaprevir in the PROVE-1/2 studies, with SVR rates of 60-70% using only 12 weeks of triple therapy. [8, 4]
In PROVE 3, SVR rates of approximately 70% and 40% were seen at 12 weeks in previous relapsers and non responders respectively, using telaprevir triple therapy, and this compared to SVR rates of 20% and 9% using PEG-IFN plus ribavirin. Rates in relapsers, but not non-responders, increased slightly when treated to 24-weeks, but relapse rates in both groups decreased with longer duration of treatment.

The preliminary nature of these studies – none of which are in people with HIV coinfection – has only provided limited tolerability data. However, discontinuation rates were 18% in first 12 weeks in the Phase 3 telaprevir studies, compared to around 4% using PEG-IFN plus ribavirin, indicating that poor tolerability remains an important limitation. Other common side effects occurred in 20-30% more patients, including nausea (~50% vs 30%), pruritis (~45% vs 23%), diahhroea (~40% vs 28%), rash (~60% vs 40%), moderate-severe rash (~25% vs 9%), vomiting (~24% vs 12%) and haemorrhoids (~ 15% vs 1%). [4, 8]

Many of the discontinuations were within the first four weeks, precluding the likelihood of a successful outcome from treatment, but later discontinuations were reported too, and as a result, future telaprevir studies will limit treatment to 8-12 weeks.

Boceprevir had a similar doubling of discontinuation rates in triple therapy compared to standard treatment arms: 15% vs 7% in patients using epoetin-alpha (EPO), and 38% vs 15% when EPO was not used. However, boceprevir had a comparable longer-term toxicity profile to dual PEG-IFN plus ribavirin therapy from week 24 to 48, allowing longer duration of treatment. Anaemia rates were higher (approximately 60% vs 34%), neutropenia (17-30% vs 12%; especially grade-2), vomiting (17-44% vs 5%) and taste changes (20-44% vs 9%) in the boceprevir groups. [7]

Very limited data on protease inhibitors in Phase 1-2 studies suggests specific side effects from these drugs; gastrointestinal complications and, for BI201335, jaundice relating to increased unconjugated bilirubin (16%) and severe rash (2.5%). Polymerase inhibitors include heterogeneous reports of nausea, neutropenia, headache, diarrhoea, dizzyness (for nukes) and generalised erythema, mild rash, headache and fatigue (for non-nukes).

Both boceprevir and telaprevir require dosing three times a day (every eight hours with food). However, SCH900518 (narlaprevir) which is also dosed TID has been studied twice-daily with QD 100mg ritonavir boosting, suggesting a similar potential for boosting HCV protease inhibitors, as with some PIs used to treat HIV. Preliminary response rates look similar to boceprevir and telaprevir, perhaps with reduced discontinuations. Studies of the Roche compound R7227 are also planned using ritonavir boosting.

COMMENT

These preliminary results in HCV monoinfection, especially for relapsers and non-responders with genotype-1, are exciting and encouraging. They also highlight the importance of studying promising new HCV compounds in HIV/HCV coinfected patients.

References

1.    Sarrazin C. New antiviral drugs against HCV – adverse event profiles and pharmacokinetic interactions. 11th Intl Workshop on Adverse Drug Reactions. 26-28 October 2009, Philadelphia. Session 1 plenary. Webcast available online.

https://lipo09.events-register.com/lipodystrophy/default.cfm?itemtypeid=15&title=Webcasts%20and%20videos

2.     Reesink HW et al. Rapid decline of viral RNA in hepatitis C patients treated with VX-950: a phase Ib, placebo-controlled, randomised study. Gastroenterology 2006;131:997-1002.

3.    Zeusem et al. Hepatology, 2005.

4.    Hezode et al. Telaprevir and Peginterferon with or without Ribavirin for Chronic HCV Infection. NEJM, Volume 360 (18):1839-1850. 30 April 2009.

http://content.nejm.org/cgi/content/abstract/360/18/1839

5.     Gane et al. First-in-man demonstration of potent antiviral activity with a nucleoside  polymerase (R7128) and protease (R7227/ITMN-191) inhibitor  combination in HCV: safety, pharmacokinetics, and virologic results  from INFORM-1. 44th Annual Meeting of the European Association for the Study of the Liver (EASL). 23-26 April 2009, Copenhagen. Late-breaker abstract 1046.

6.     Gane et al. 60th Annual Meeting of the American Association for the Study of Liver Diseases. Boston, Massachusetts. 30 October – 3 November 2009. Abstract 193.

7.    Kwo P et al. HCV SPRINT-1 final results: SVR 24 from a Phase 2 study of boceprevir plus pegIntron (Peginterferon alfa-2b)/ribavirin in treatment-naive subjects with genotype 1 chronic hepatitis C. 44th European Association for the Study of the Liver (EASL). 23-26 April 2009, Copenhagen. Oral abstract 4.

8.     McHutchinson et al. Telaprevir with peginterferon and ribavirin for chronic HCV genotype 1 infection. NEJM, Volume 360 (18):1827-1838. 30 April 2009.
http://nejm.highwire.org/cgi/content/full/360/18/1827

This issue of HTB went to press just after the 12th EACS conference and detailed reports from this meeting will be included in our next issue.

As a stop press we only include one article:

• EACS releases three updated management guidelines

Although the abstracts from the meeting are not currently available online, this year a comprehensive programme of lectures and sessions are
due to become available as webcasts:

http://www.multiwebcast.com/eacs/2009/12th

The European AIDS Clinical Society publishes three management guidelines that make extensive use of summaries, bullet point list and supportive tables to produce resources that are easy to follow resources. The three main updates (version 5) were launched at this year’s conference.

PDF versions are now available to download from the societies website. Additional tables not included in the PDF and printed booklets are also available online.

http://www.europeanaidsclinicalsociety.org/

The main changes to each guideline are outlined below

ARV guidelines

• A check list for initial and routine clinic management and a new flow chart for assessing and supporting a patients readiness to start ARV treatment. This includes the importance of asking about depression and mental health, and alcohol and recreational drug use.
• In primary infection, although a CD4 count <350 three months after infection is included as a criteria to start treatment, the guidelines recognise that most patients are likely to wait at least until six months.
• Treatment is recommended for any patient with a CD4 count <350, and at between 350-500 in patients older than 50 years, coinfection with HCV, HBV or other listed health complications.
• A new section focuses on HIV and TB coinfection.
• Switching drugs for toxicity is overly cautious for anyone other than naive patients, perhaps underestimating the importance of tolerability when modifying treatment however pre-treatment someone may be.
• PEP is recommended ideally within 4 hours of exposure, and not later than 48 hours. Surprisingly there is no reference to viral load of the HIV-positive partner as a factor in assessing risk.

Prevention and management of non-infectious comorbidities

This management guideline has expanded considerably, now addressing many of the comorbidities associated with an older HIV cohort, especially cardiovascular, renal, hepatic, metabolic, neoplastic, done and mental health complications. Recommendations are not graded based on the quality of evidence.

• Screening sections have been expanded for renal, bone, neurocognitive disorders, depression and cancer.
• Lipid management is covered in a separate table, which notably does not include triglyceride management due to less evidence suggesting elevated TG as an independent risk factor for clinical complications.
• Bone screening refers doctors to the FRAX calculator (www.shef.ac.uk).
• Kidney screening includes eGFR at baseline and a new recommendation to include dipstick testing.
• Many additional tables are available as web resources (ie for neurocognitive screening, lipoatrophy treatments etc).

Hepatitis coinfection

The main changes in the hepatitis coinfection guidelines include:

• To start appropriate ARVs when CD4 count is <500 c/mm3 in people who need HBV treatment.
• That this is likely to be lifelong unless the patient is HBV eAg+ who may clear HBV and that treatment could be cautiously stopped six months after conversion to eAg–.
• New information on hepatitis D (HDV) which increase the risk of fibrosis progression in HBV infection.
• That people with CD4 count < 350 should probably start ARVs prior to HCV treatment to increase the chance of success (SVR).
• Early HCV treatment is recommended for HIV-positive people identified in acute HCV infection.
• Non responders (< 2 log HCV RNA drop at week 12) should stop treatment to wait for new options.
• People who relapse can consider retreating with longer duration.
• That HIV is no longer a contraindictation for liver transplant and that timely referral to transplant lists is therefore important.

The newly named 11th International Workshop on Adverse Drug Reactions and Co-morbidities in HIV was held this year from 26–28 October 2009 in Philadelphia. The workshop has expanded its earlier focus on lipodystrophy to include coinfection, particularly hepatitis and age-related morbidities including bone, cardiovascular, oncology and neurocognitive complications.

The format for the workshop continues to provide a focused forum for the range of metabolic complications but also recognises that these symptoms are becoming more difficult to view in isolation.

Reports form the meeting this year include:

• Intermuscular tissue is decreased in HIV infection
• High incidence and risk factors for diabetes in French cohort
• Gender and race differences in lipodystrophy symptoms
• Lipodystrophy is common in children from three European cohorts
• Visceral adipose tissue returns to baseline after stopping therapeutic rHGH
• Reduced levels of vitamin D in patients taking efavirenz
• Association between inflammation and sleep apnea in the MACS cohort
• Sports supplements impact on serum creatinine and eGFR markers of renal function

Webcasts from the meeting are due to be posted to the conference website shortly.

https://lipo09.events-register.com/lipodystrophy/

The first study in the main conference looked at a intermuscular adipose tissue (IMAT) – the distribution of fat that is beneath the muscle facia and muscle tissue – as a new parameter of metabolic disturbances. Led by Carl Grunfeld with the FRAM study, this group has provided important insight into the association of HIV to metabolic changes by using full body MRI to identify changes and including an HIV-negative control group. Results from the study concluded that fat loss and fat gain are separate unrelated dysfunctions and that fat loss rather than fat accumulation is the driving mechanism behind HIV-related changes.

This year the group hypothesised that IMAT, which has been reported as increasing in obese HIV-negative women and having a strong relationship to insulin sensitivity, would behave similarly to visceral adipose tissue (VAT) and would be increased in HIVpositive patients. IMAT is preserved in familial and decreased in generalised congenital lipodystrophy.

In fact, they reported that IMAT was 51% lower when comparing 425 HIV-positive patients to 211 HIV-negative controls, even after adjusting for demographics and lifestyle (adjusted to -48%), although somewhat attenuated after controlling for VAT, SAT and skeletal muscle volume (adjusted to -21%). All comparisons were significant (p<0.0001).

In HIV-positive people but less so in controls, IMAT was associated with higher levels of VAT, trunk SAT and leg SAT.

As both IMAT and subcutaneous adipose tissue (SAT) were decreased with exposure to d4T, the study concluded that IMAT shared similar cellular origins to SAT. Although the clinical implications are less significant in countries that have moved away from using d4T and ddI, this finding is likely to be most relevant to those where it is still widely used.

Ref: Grunfeld C et al. Intermuscular tissue is decreased in HIV infection. 11th Intl Workshop on Adverse Drug Reactions. 26-28 October 2009, Philadelphia. Oral abstract O-01. Antiviral therapy 2009; 14 Suppl 2: A3.

The incidence of diabetes and related risk factors from the ANRS C08 APROCO-COPILOTE cohort was presented by Jacqueline Capeau. [1]

The cohort included 643 patients on their first protease inhibitor-based regimen, followed from 1997-8 for nine years, 40% of who were ARV-naive when the study started. Approximately 80% were male and 4,500 patient years of follow-up (PYFU) contributed to the analysis.

Diabetes was diagnosed as fasting glycaemia >7.0 mmol/L or 2-hour oral glucose tolerance test (OGTT) >11.1 mmol/L and/or treatment for diabetes.

Cardiovascular risk was calculated using Framingham.

The group reported a high incidence of diabetes in both men (10.8 per 1000 PYFU; 95%CI: 7.9-14.3) and women (11.4; 9%CI: 5.7-20.3). After adjusting for family history, age, BMI and waist:hip ratio, the following factors were associated with new onset diabetes: age > 40 years, BMI >25, WHR >0.97 in men and >0.92 in women and use of d4T or indinavir. HIV-related markers including CD4, CD4:CD8 ratio, viral load, ethnicity and HCV status were not associated.

When compared to patients with normal glycaemic function, people with diabetes were older (median 43 vs 35 years), had higher BMI (median 24 vs 21), had higher rates of hypertension (50% vs 18%) and family history of diabetes (37% vs 16%), all p<0.001.

Diabetic patients also had a significantly higher 10-year cardiovascular risk (13% vs 3%).

The researchers commented that these rates were four times higher than in HIV-negative control cohort with similar adipose profile. [2]

COMMENT

The study hasn’t so far found that impaired glucose tolerance has predicted development of diabetes. Over time the incidence of new cases appears to have levelled out, perhaps relating to reduced use of d4T and ddI. Naive patients using neither of these RTIs seem to be protected, although further analyses are needed to see whether levels remain higher than in the general population.

References
1. Capeau J et al. High incidence and risk factors for diabetes over the 9-year follow-up after first generation protease inhibitors’ initiation in the ANRS C08 APROCO-COPILOTE cohort. 11th Intl Workshop on Adverse Drug Reactions. 26-28 October 2009, Philadelphia. Oral abstract O-05. Antiviral therapy 2009; 14 Suppl 2: A5.
2. Meisinger C et al. Sex differences in risk factors for incident Type 2 Diabetes Mellitus: the MONICA Augsburg Cohort Study. Arch Intern Med 2002; 162: 82-89.
http://archinte.ama-assn.org/cgi/content/abstract/162/1/82

The prevalence, type and severity of lipodystrophy in the Ontario Cohort Study was assessed using the ACTG body image questionnaire. Results from a cohort study of 746 Canadian patients on stable HAART confirmed previously reported side effect profiles in relation to gender and race.

This was a largely male (85%) and non-Black (85%) study. Median age was 48 years (IGR 42-55) and median duration of HIV infection was 13 years (IQR 7-18).

The overall prevalence of 58% lipodystrophy was similar by gender and race. However, men reported fat loss more frequently than women (31% vs 11%, p<0.0001), especially in the face (45% vs 30%, p=0.03) but similarly in the legs and buttocks. Women were more likely to report central fat accumulation (26% vs 15%, p<0.0001) especially in the abdomen (5% vs 46%, p<0.001) and breasts (31% vs 17%, P<0.0001). Women were almost twice as likely to report both symptoms (21% vs 12%, p<0.0001).

The study reported no differences by race (Black vs non-Black) for men, but Black women had a significantly higher rate of fat accumulation than non-Black women (57% vs 38%, p=0.05).

COMMENT

Although there are limitations in this study in terms of limited racial and gender balance, and reliance on personal perception, the overall observations are important for sensitivity of individual patient management. This is especially true as no combination has been identified that has not been associated with fat accumulation, including studies with recently approved ‘lipid-friendly’ protease inhibitors or with raltegravir.

The associated between lipohypertrophy, gender and race deserves further study.

Ref: Loutfy M et al. Gender and ethnicity differences in body change and distress of HIV-positive individuals taking antiretroviral therapy in Ontario. 11th Intl Workshop on Adverse Drug Reactions. 26-28 October 2009, Philadelphia. Poster abstract P-08. Antiviral therapy 2009; 14 Suppl 2: A29.

Researchers from 14 sites in Belgium, Poland and Italy reported the prevalence of lipodystrophy in a cohort of 468 children and adolescents (92% infected at birth). Data collected included demographic and clinical history and used standardised assessment to determine fat loss or accumulation in the face, limbs, buttocks, breasts, neck and trunk.

The cohort was evenly split by gender, with median age 13.5 years (IQR 9.9-17.0). Tanner puberty stage included 28% stage I and 34% stage V. In this group, 73% were white and 22% Black African. HIV treatment was used by 95% of the cohort for a median 8.8 years, with 62% having viral load suppressed <50 copies/mL. The median CD4% was 31% (IQR 24-38) and just over 300 children were currently asymptomatic.

Assessment of symptoms was by clinician-completed questionnaire. Over 40% of children had at least one lipodystrophy symptom: 15% had just fat loss, 13% just fat accumulation (mostly trunk) and 13% had both symptoms. This group included 14 cases of severe fat accumulation and 11 cases of both severe fat loss and fat accumulation.

In multivariate analysis, after controlling for duration of treatment, maternal lipodystrophy, maximal CDC status, and having ever used d4T, indinavir, d-drugs and efavirenz, significant associations were found for d4T use (AOR 4.23; 2.02, 8.85), efavirenz use (AOR=2.72; 1.36, 5.46), indinavir use (AOR 3.23) and clinical stage (AOR 3.30; 1.28, 8.02) and either fat loss or fat accumulation.

Even stronger associations were found for children who had both symptoms.

Maternal lipodystrophy was also associated with an adjusted OR of 3.01 (1.78, 5.57) for any symptom and 4.75 (1.60, 14.20) for both symptoms.

Ref: Alam NM et al. Risk factors for body fat redistribution in a European cohort of HIV-infected children and adolescents. 11th Intl Workshop on Adverse Drug Reactions. 26-28 October 2009, Philadelphia. Poster abstract P-06. Antiviral therapy 2009; 14 Suppl 2: A27.

Central fat accumulation remains one of the most distressing but least understood metabolic complications, with very limited management options. Several studies have reported that recombinant Human Growth Hormone (rHGH) can reduce central visceral adipose tissue (VAT), although earliest studies at higher doses (4-6 mg/day) were associated with significant toxicity. Additionally, any benefit seemed dependent on maintaining treatment, and the optimal dose remained to be established.

It was important to see the 3-years results from a study from the Massachusetts General Hospital, presented by Steven Grinspoon, carried out in people with reduced growth hormone (GH) secretion (peak GH <7.5 ng/mL). [1] This was a randomised double-blind study of low dose rHGH (an average dose of 0.33 mg/day: starting at 2 mcg/kg/day but increasing to 6 mcg/kg/day, titrating to the upper quartile of normal IGF-1 range). After 18 months patients crossed over to either active drug or placebo, depending on their original randomisation. The 18 month initial results have already been published. [2]

Pooled analysis for both arms showed that 18 months treatment significantly reduced mean (+SD) VAT compared to placebo (-7.3 +21.3% vs +4.8 +22.7%, p<0.0001) and trunk fat (-3.2 +15.3% vs +2.4 +13.1%, p=0.003). rHGH also had a statistically positive effect on reducing systolic and diastolic blood pressure, triglycerides and LDL-cholesterol and increasing lower limb fat, but had a negative glyceamic affect: increasing fasting glucose and 2-hour glucose on OGTT (see Table 1). No impact for seen for intima media thickness, though this was not elevated at baseline.

During the crossover period, the benefits of rHGH on VAT reversed to baseline within 6 months. The increase in IFG-1 seen during 18 month treatment (approximately +100ng/mL increase from baseline) also dropped within 2-4 weeks of discontinuation.

Table 1: Pooled effect of rHGH vs placebo at 18 months (mean%, ±SD)

The importance of continuing treatment in order to maintain any reduction in VAT has also been reported with tesamorelin, which although has reduced toxicity, appears to reverse benefits back to baseline VAT levels if discontinued. An FDA decision on approval of tesamorelin is expected in the second quarter of 2010.

References
1. Grinspoon S et al. Effects of treatment and discontinuation of low dose physiologic growth hormone in HIV patients with abdominal fat accumulation: a randomised, placebo-controlled 36-month crossover trial. 11th Intl Workshop on Adverse Drug Reactions. 26-28 October 2009, Philadelphia. Oral abstract O-02. Antiviral therapy 2009; 14 Suppl 2: A3.
2. Lo et al. Low-dose physiological growth hormone in patients with HIV and abdominal fat accumulation. JAMA 2008;300(5):509-519. (6 August 2008).
http://jama.ama-assn.org/cgi/content/full/300/5/509

Todd Brown and colleagues from Johns Hopkins University presented results from a retrospective analysis that supports a link between efavirenz and reduced levels of vitamin D. [1]

The study compared 25-(OH) vitamin D levels from stored samples from 87 treatment naive patients and compared this to levels 6-12 months after starting treatment containing efavirenz (n=51) or non-efavarinz (n=36; 89% PI-based).

Several studies have reported an association between NNRTIs and reduced levels of vitamin D, including a recent UK study linking low levels to the use of efavirenz. [2]

The current study reported a prevalence of mild, moderate and severe vitamin D deficiency at baseline in 84% (<32 ng/mL/<80 nmol/L), 56%% (<20 ng/mL/<50 nmol/L) and 33% (<15 ng/mL/< 37.5 nmol/L) patients respectively. Median levels were lower in non-white compared to white patients (16 vs 30 ng/mL, p<0.0001) and in winter compared to summer (15 vs 27 ng/mL, p<0.001).

Factors associated with low levels at baseline included race (Prevalence Ratio 6.7 95%CI: 1,7, 25.6; p=0.006), season (PR 4.6; 1.2, 17.8; p=0.03) and duration of HIV infection (PR 1.06; 1.02, 11.09; p=0.003).

Pre- and post-HAART levels in the efavirenz group dropped from 22.6 to 18.4 and increased from 21.2 to 22.9 in the non-efavirenz group (p=0.05 between group comparison post-HAART). After adjusting for baseline 25(OH)D, race and season, the adjusted mean difference between group was -5.1 +1.5 ng/mL, (p=0.001). Using the <15 nmol/mL cut-off the percentage of patients with severe depletion increased from 27% to 48% in the efavirenz group and reduced from 42% to 31% in the non-efavirenz group.

The adjusted prevalence ratio for efavirenz use was 1.8 (95%CI 1,2, 2,8, p=0.007).

No association was found with use of tenofovir, abacavir or AZT.

References:
1. Brown TT et al. Association between initiation of antiretroviral therapy with efavirenz and decreases in 25-hydroxyvitamin D. 11th Intl Workshop on Adverse Drug Reactions. 26-28 October 2009, Philadelphia. Oral abstract O-20. Antiviral therapy 2009; 14 Suppl 2: A15.
2. Welz et al. Efavirenz use is associated with severe Vitamin D deficiency in a large, ethnically diverse urban UK HIV cohort. Poster abstract TUPEB186. 5th IAS conference, 19-22 July 2009, Cape Town.
http://www.ias2009.org/pag/Abstracts.aspx?AID=3402

Prompted by the concern that systemic inflammation may contribute to sleep apnea, Susheel Patil and colleagues from Johns Hopkins University presented an interesting analysis from the gently named SIESTA study (Study of Immune Effects on Sleep, (HIV) Treatment and Apnea).

The study looked at obstructive sleep apnea (OSA) and the relationship with inflammation markers (TNF-alpha soluble TNF-a receptors I and II and IL-6), in three groups of men from the MACS cohort: HIV-positive and not on HAART (n=41), HIV-positive and on HAART (n=58) and HIV negative (n=60). Severity of OSI was defined by the number of events per hour detected during a nocturnal sleep study: 5-15 = mild, 15-30 = moderate, and >30 = severe. Obesity is the strongest predictor of OSI, but OSI is also independently associated with hypertension, cardiovascular disease, stroke, diabetes mellitus and reduced quality of life.

OSI >15 was higher in the HIV- negative group (57%) compared to the HAART (41%) and no-HAART (44%) groups. However, the HIV-negative group had a significantly greater mean BMI (28.6 +7.2kg/m2) and waist circumference (98.6 +16.9cms) compared to the HAART (25.5 +4.5kg/m2 and 93.8 +11.5cm) and no-HAART (25.4 +4.1 kg/m2 and 91.8 +12.8) HIV-positive groups and a trend to greater trunk weight.

When looking at participants with normal BMI (<25 kg/m2) however, the relationship indicated a trend for higher prevalence in the no-HAART group: 25% HIV-negative (n=20), 24% on HAART (n=29) and 50% in the no HAART group (n=22); (p=0.1).

Median levels of all four inflammatory markers were higher in the HIV-positive men compared to the HIV-negative men, and were higher in the no-HAART group compared to the HAART group. Within the no-HAART group, men with moderate – severe OSA had higher levels of TNF-a and IL-6 compared to men with no or less severe OSI, although this difference was not observed between men in the other groups.

The study concluded that rates of OSI were high in HIV-positive men, even when BMI was normal, and that more severe symptoms was associated with systemic inflammation suggesting a different aetiology compared to men who are HIV-negative.

Ref: Patil SP et al. Association between systemic inflammation and obstructive sleep apnea in men with or at risk for HIV infection from the Multicenter AIDS Cohort Study (MACS). 11th Intl Workshop on Adverse Drug Reactions. 26-28 October 2009, Philadelphia. Oral abstract O-25. Antiviral therapy 2009; 14 Suppl 2: A19.

Several case studies showing the impact of creatinine supplementation on eGFR results, were presented in a poster by Graeme Moyle, from the Chelsea and Westminster Hospital, London. Estimated GFR is now routinely included in renal monitoring using the MDRD calculation, which incorporates serum creatinine, together with age, sex and ethnicity.

Six HIV-positive male patients (aged 25- 55) on stable HAART were referred to an HIV/renal clinic due to elevated serum creatinine (range 131-257 umol/L) and low eGFR. All were normal blood pressure and no history of diabetes. Proteinuria levels were normal and confirmed by urinary protein:creatinine ratio. Each patient routinely used protein and creatine supplementation as part of a muscle-building gym routine.

Three months after 5/6 patients discontinued the supplements, serum creatinine levels consistently dropped to between 98 and 118 umol/L and eGFR reported to normalise (eGFR data was not shown).

Although dietary intake of creatine is 1g/day, supplementation can increase this 20-30 fold, and intramuscular concentrations can remain elevated for several weeks. Creatine is converted to creatinine relative to its concentration which can increase serum creatinine despite normal renal function. The poster suggested that ARV exposure may also be involved but also that the association of raised serum creatinine with creatine ingestion has not been published outside of the HIV context.

COMMENT

This study highlights the importance taking a history of supplement use to consider this as a cause for elevated creatinine or low eGRF.

Ref: Moyle G et al. The pitfalls of the estimated glomerular filtration rate – ‘hitting the gym and creatine supplementation’. 11th Intl Workshop on Adverse Drug Reactions. 26-28 October 2009, Philadelphia. Poster abstract P27. Antiviral therapy 2009; 14 Suppl 2: A49.

The AIDS Vaccine conference is one of the most important scientific meetings on AIDS vaccine research and development. It was attended by more than 1,000 delegates and included over 400 scientific presentations.

Programme highlights that increased the profile of the meeting this year, included a full presentation from the Thai phase III trial that controversially reported top level results a few weeks earlier in a press release.

We report this study here, which coincided with publication in the NEJM.

• Thai HIV Vaccine Trial results presented and published

Conference programme:

http://www.hivvaccineenterprise.org/conference/2009/scientific_program.aspx

Several sessions including the press conferences, are available as webcasts, together with searchable online abstracts and PDF files of many or the posters or presentations:

http://www.hivvaccineenterprise.org/conference/2009/webcasting.html

Abstracts from the conference are published as an open access online supplement in Retrovirology:

http://www.retrovirology.com/supplements/6/S3

In tandem with the presentation of the data that took place at the AIDS Vaccine 2009 conference in Paris, the results of the RV144 trial were published online in the New England Journal of Medicine. Access to the paper and the accompanying editorial is free of charge. Three different analyses of the results are presented in sequence: the intent-to-treat analysis (ITT), which includes everyone enrolled and randomised to receive vaccine or placebo, a per protocol (PP) analysis limited to everyone who received all immunisations on schedule, and finally a modified ITT (mITT) analysis that excludes seven individuals who reportedly turned out to be HIV-infected at the time of their first immunisation.

• ITT: Total n=16,402. Cases of HIV infection: 76 placebo, 56 vaccine. Efficacy: 26.4% (95% confidence interval [CI], –4.0 to 47.9; p=0.08)
• PP: Total n= 12,452. Cases of HIV infection: 50 placebo, 36 vaccine. Efficacy: 26.2% (95% CI, –13.3 to 51.9; p=0.16)
• mITT: Total n=16,395. Cases of HIV infection: 74 placebo, 51 vaccine. Efficacy 31.2% (95% CI, 1.1 to 51.2; p=0.04)

The data suggests the possibility of a marginal protective effect, almost entirely concentrated during the first year of the study. Kaplan-Meier plots of the infection rate over time show a divergence initially, but the rates in the vaccine and placebo groups are superimposable from week 52 onwards. Subgroup data are also reported, but the statistics are uncorrected for multiple analyses and should be interpreted with great caution. With this caveat, there is a hint that the difference between the vaccine and placebo was greatest among those at lowest risk of HIV exposure. The age group breakdown also indicates the difference between vaccine and placebo groups was concentrated in the 20-25 age group; there is no difference in the number of infections between the groups among those under 20, and very little difference among those over 26. Among participants aged 20-25, there were 20 infections in the vaccine group and 40 in placebo.

In terms of the viral load outcomes in people who acquired infection, the ITT analysis shows a trend in the wrong direction; viral load was higher on average among vaccine recipients (4.36 log vs. 4.21 log, p=0.09). However this trend disappears in both the PP and mITT analyses. There were no differences in post-infection CD4 T cell counts in any of the analyses.

As to why the only statistically significant result is reported last in the published paper (in contrast to the September 24 press announcement, in which the mITT was the only result given), it appears that the RV144 protocol specified that the primary analysis would be ITT. The paper states that the mITT analysis was used as the primary analysis for the interim efficacy evaluation (which was conducted by the Data Safety Monitoring Board in July of 2007) and then, five months before the study was unblinded, a decision was made to make the mITT the primary analysis. Reading between the lines, perhaps the reviewers of the manuscript
were not satisfied that this late adoption of the mITT as the primary analysis justified listing the result first in the paper. It is currently unclear why the RV144 protocol did not specify the mITT as the primary efficacy analysis from the start. As the import of the trial results are mulled by the larger community, it will be important to gain some clarity as to exactly how these events played out.

So far, in the limited time observers have had to digest the data, the main issues that are being discussed are the suggestion of a transient, time-limited effect and what might explain it (vaccines generally work by the induction of immunological memory, which is typically long-lived) and the hint that vaccine-mediated protection might be easier to achieve in individuals with less frequent HIV exposure compared to those at high risk.

Regrettably, the release of the data today does not change the fact that it was an appalling and woefully short-sighted decision to only release the mITT analysis to the press on September 24. On the conference call hosted by AVAC that took place that day with investigator Merlin Robb and Peggy Johnston from NIAID, Robb explicitly stated that only 16,395 people had been enrolled into the trial. Not only was this not true, but it turns out that vaccine/placebo distribution of the 7 people excluded from the mITT was crucial to the attainment of statistical significance: five of these individuals were in the vaccine group and two in placebo. By cherry-picking the mITT to announce, the RV144 investigators have created suspicion and uncertainty in a field that they well know is already plagued by controversy. Their decision will only serve to complicate efforts to glean useful information from the trial data.

Source: www.tagbasicscienceproject.typepad.com (20 Oct 2009)

The webcast of the press conference about the trial results is now available online (scroll down to the bottom of the page to the Tuesday, 20 October press conference link).

http://www.hivvaccineenterprise.org/conference/2009/webcasting.html

References
1. Supachai Rerks-Ngarm et al. Vaccination with ALVAC and AIDSVAX to prevent HIV-1 infection in Thailand. 20 October 2009 (10.1056/
NEJMoa0908492).
http://content.nejm.org/cgi/content/full/NEJMoa0908492
2. Dolin R. HIV vaccine trial results – an opening for further research. NEJM Editorial. 20 October 2009 (10.1056/NEJMe0909972).
http://content.nejm.org/cgi/content/full/NEJMe0909972

Additional reading:

Earlier articles detailing the unfolding controversies around this study and the early press release focusing on a positive trial result are covered in a number of articles from the TAG basic science web log.

http://tagbasicscienceproject.typepad.com

- Marginal HIV vaccine trial result raises hopes, eyebrows. (25 Sep 2009).
- Thai HIV vaccine trial: additional history & links. (28 Sep 2009).
- Deconstructing the Thai trial vaccines. (29 Sep 2009).
- Did the world get a “fair glimpse” of the Thai vaccine trial data? (05 Oct 2009).
- Thai HIV vaccine trial update: uncertainty reigns. (15 Oct 2009).

Introduction

The following short reports are summaries from some of the interesting studies presented at ICAAC this year. As were not able to cover this meeting in person, all information is dependent on the online posters.

Reports in this issue of HTB include:

• Smoking masks the long-term benefits of HAART on lung function
• Recent ARVs and the blood/brain barrier: CSF drug concentrations of darunavir/r and raltegravir
• Alcohol and marijuana may reduce drug levels of atazanavir and efavirenz
• Raltegravir body composition study: 48-week DEXA results

ICAAC unfortunately routinely removes online access shortly after the meeting and is one of the few medical meetings covering HIV care that does not support continued open access to this resource.

As we went to press these were still available online:

http://www.posters2view.com/icaac

[Username: ICAAC; Password: SanFran]

A poster by Jan Gerstoft and colleagues from Copenhagen University Hospital looked at the interaction between changes in lung function in relation to smoking and HIV treatment.

Between October 2000 and November 2001, 63 HIV-positive patients had initial lung function assessed by a panel of tests (including forced expired volume, functional vital capacity, peak flow, residual volume [RV%] and total capacity and diffusing capacity/alveolar volume [DLCO/VA%]), with follow-up assessments a median of 4.5 years later (range 3.8-4.7 years).

Most participants (87%) were already on HAART at baseline for a median of about five years (range 16-79 months) with all but two on HAART at the follow-up visit (with 85% and 89% of these patients having viral load <100 copies/mL at each time point, respectively).

Some abnormal lung function parameters were present at baseline in both smoking (n=30) and non-smoking (n=33) participants, and some were further reduced in smokers. Specifically, DLCO/VA% was decreased in both groups, with lung function compatible with early obstructive lung disease. At follow-up these levels normalised in non-smokers and improved in smokers to the baseline levels of the non-smoking group. However, results for residual volume, which returned to normal for non-smokers, increased further in the smoking group.

The researchers concluded that this study showed that HAART was beneficial for lung status and that HIV-related changes can reverse over time in non-smokers. However, smoking masks many of these potential benefits.

COMMENT

As most participants had already been on HAART for many several years at baseline, and results were not divided by HAART use and viral load, the study did not quantify the extent and timeline of the benefits due to antiretroviral therapy. Nevertheless, the suggested positive impact of HAART on lung function is important and the results reinforce the importance of smoking cessation.

Ref: Gerstoft J et al. Changes of lung function in an optimally treated HIV population: a 4.5 year follow up study. 49th ICAAC, 12-15 September 2009, San Francisco. Poster abstract H-1561.
http://www.posters2view.com/icaac/view.php?nu=H-1561

The issue of drug penetration into the cerebrospinal fluid (CSF) is an increasing focus for all antiretrovirals, but has particular importance given the interest in nucleoside-sparing regimens. These include studies looking at boosted-PI monotherapy as a maintenance strategy after initial viral suppression with triple drug therapy and dual NNRTI + PI/r or raltegravir + PI/r combinations.

Scott Lettendre’s group presented encouraging results from two studies at ICAAC: on darunavir/r and on raltegravir, supported by Tibotec and Merck respectively.

The darunavir study measured 29 CSF and plasma pairs from 16 HIV-positive patients between August 2006 and August 2008, and compared levels to the median IC50 for wild-type virus (2.75 ng/mL). [1]

Participants were a median 48 years, 62% were Caucasian and 19% had HCV co-infection. Median CD4 cell count was 197 cells/mm3. Viral load was detectable in 38% of blood and 10% of CSF samples. Median duration of darunavir was 7.5 months (IQR 3.6 – 14.6).

Darunavir was detected in all CSF specimens with a median concentration of 56.9 ng/mL (IQR 39.6 – 81.4). The median total plasma concentration (AUC) was 4,094 ng/mL (IQR 2,993 – 6,410) with a median CSF-to-plasma ratio of 1.4%. The median unbound plasma concentration was 542 ng/mL (IQR 376 – 971) with a median CSF-to-plasma unbound ratio of 9.4% (IQR 6.8 – 14.2%).

DRV concentrations in CSF exceeded the IC50 of wild-type HIV in all specimens by a median of 20-fold.

The raltegravir study had a similar design, with 22 matched plasma/CSF samples from 18 HIV-positive patients. Demographics were also similar: median age 46 years, 89% Caucasian, 12% HCV coinfection with a median CD4 of 276 cells/mm3. [2] The median raltegravir inhibitory concentration (IC50) for wild-type HIV is 3.4 ng/mL.

Raltegravir was present in all CSF specimens with a median concentration of 14.5 ng/mL. The median plasma concentration was 260.9 ng/mL (IQR 2.0 – 640.4) with a median CSF-to-plasma ratio of 5.8% (IQR 2.1%-17.8%). CSF concentrations correlated with plasma concentrations (r = 0.49, p = 0.02) but not with post-dose sampling time (p > 0.50). Raltegravir concentrations in CSF exceeded the IC50 of wild-type HIV in all specimens by a median of 4.3-fold (IQR 2.7-7.7). HIV RNA levels were undetectable in 20 of 21 (95%) CSF specimens and in 13 of 21 (62%) plasma specimens.

Each study concluded that the study drug penetrated CSF in concentrations that are in the therapeutic range to suppress wild-type HIV and would be expected to contribute antiviral activity in the CSF as part of combination therapy.

Drug levels of both drugs in CSF correlated better with total levels in plasma suggesting that therapeutic drug monitoring could indicate effectiveness in the nervous system. Unbound plasma concentrations of darunavir were less closely correlated.

References
1. Best B et al. Darunavir concentrations in CSF exceed the median inhibitory concentration. 49th ICAAC, 12-15 September 2009, San Francisco. Poster abstract A1-1312.
http://www.posters2view.com/icaac/view.php?nu=A1-1312
2. Best B et al. Raltegravir concentrations in CSF exceed the median inhibitory concentration. 49th ICAAC, 12-15 September 2009, San Francisco. Poster abstract A1-1311.
http://www.posters2view.com/icaac/view.php?nu=A1-1311

While some aspects of the lipodystrophy syndrome are better understood and managed, fat accumulation (lipohypertrophy), principally central visceral adipose tissue (VAT), remains unexplained and is still associated with all families of antiretrovirals. While this mechanism is unknown, it appears to have little relationship to the atherogenic lipid and glucose changes that appear to be a separate set of lipodystrophy symptoms.

The DEXA results reported here are from a sub-set of 76/563 naive patients from the double-blind placebo-controlled STARTMRK trial, randomised to either raltegravir or efavirenz, each with tenofovir/FTC. This analysis compared baseline to week 48, with follow-up planned to week 96. Metabolic parameters included fasting lipid and glucose changes and relationship to NCEP goals.

Baseline characteristics for patients in the sub study were similar to the larger group and are summarised in Table 1. Median CD4 count and viral load (in the substudy) was approximately 200 cells/mm3 and 5 log copies/mL.

At 48 weeks there were few overall changes and no significant differences between the two arms. Total fat increased in both arms by around 16-20% in both limbs and trunk (see Table 2). Investigator reported observational changes were two cases of mild fat accumulation in the blinded efavirenz arm. No patients reported lipodystrophy symptoms.

Lipid changes were significantly great in the efavirenz group: TC +33 vs +10; HDL +10 vs + 4; LDL +16 vs +6; and TG +37 vs -3 mg/dL (all p<0.001). The change in the TC:HDL ratio was -0.1 vs -0.3 in the efavirenz and raltegravir groups (p=0.292).

Table 1: Baseline Characteristics in the DEXA Sub-Study

Table 2: Body composition changes in STARTMRK at 48 weeks

N = # of patients in the treatment group. † Mean % changes from baseline are based on the measurements of the pts who were measured at baseline and the time point assessed.

COMMENT

The lipohypertrophy profile of each new drug should be included routinely in all Phase III antiretroviral trials. While raltegravir was originally approved over two years ago (October 2007 in the US), the first information on fat accumulation was only presented at ICAAC this year (September 2009). It is now unfortunate that this is based on DEXA rather than CT scans: while DEXA can provide information about limb fat loss, it is not able to separate visceral fat from subcutaneous fat.

While no signal of early problems is reassuring, 48-weeks is probably too early to see significant changes. As efavirenz has previously been linked to fat accumulation, similar results at this timepoint should be interpreted cautiously.

References
1. Berger D et al. Metabolic profiles and body composition changes in treatment-naïve HIV-infected patients treated with raltegravir (RAL)-based vs. efavirenz (EFV)-based combination therapy: 48-week data. 49th ICAAC, 12-15 September 2009, San Francisco. Poster abstract H-1571.
http://www.posters2view.com/icaac/view.php?nu=H-1571

Two small studies from the same research group looked at the association between substance use, including alcohol and marijuana, and levels of HIV drugs.

The first study reported that trough concentrations of atazanavir were inversely related to use of tobacco and marijuana in 32 ‘substance using’ (SU) patients from four US sites compared to 35 non-using (non-SU) patients. [1]

Substance use (% of SU patients) followed NIDA criteria and included alcohol (41%), cocaine (19%), marijuana (38%), opioids (22%) and tobacco (91%). 43% of these patients used multiple substances.

During the study period, patients had to complete three clinic visits, for entry, trough and directly observed therapy (DOT), and take scheduled doses of atazanavir at the same time for 4 days before each visit.

Adherence assessment and counseling prior to plasma sampling and each scheduled clinic visit were performed and recorded.

Multiple linear regression models were used to determine factors associated with atazanavir concentrations, immunological and virologic responses while adjusting for covariates. Other demographics including race, gender, ethnicity and BMI were included in the analysis.

Significant reductions in ATV trough concentrations were associated with tobacco and marijuana use (p<0.05) but not with other substances. 36% and 50% of tobacco and marijuana users, respectively had ATV concentrations below the therapeutic range (p<0.05). However, no significant direct effects were linked to viral load or CD4 count.

Table 1. Substance use (SU) and atazanavir trough levels*

* Median, ug/ml (IQR). For HTB, rounded to two decimal points.

The researchers concluded that the underlying mechanism may include enzyme induction, but that further studies were needed for this to be determined.

The second study looked at efavirenz metabolism in relation to the G516T single nucleoside polymorphisms (SNPs) in the CYP2B6 enzyme. Previous studies have demonstrated that GG > GT > TT polymorphisms inhibit efavirenz metabolism resulting in higher plasma concentrations, slower drug clearance, and sometimes increased toxicity.

Based on 516 genotypes, 37 patients (SU n=18; non-SU n=19) were categorised as extensive (GG, n=19), intermediate (GT, n=13), and slow (TT, n=5) metabolisers. These genotypes with were significantly associated with efavirenz trough concentrations (p=0.04). Significantly lower median (IQR) efavirenz concentrations were linked to tobacco use (1.76 ug/mL; (1.31-2.13) vs 2.29 ug/mL (1.88-4.01), p=0.04) and alcohol use (1.41 ug/mL (0.66-1.88) vs 2.25 ug/mL (1.76-2.48), p=0.02) in the extensive metaboliser group with lower CD4 counts and higher viral loads.

As with the atazanavir study, substance use had no significant relationship to antiviral responses.

References
1. Fehintola FA et al. Tobacco and marijuana uses significantly decrease atazanavir (ATV) trough concentrations in HIV infected individuals. 49th ICAAC, 12-15 September 2009, San Francisco. Poster abstract H-231.
http://www.posters2view.com/icaac/view.php?nu=H-231
2. Brazeau D et al. Effects of CYP2B6 single nucleotide polymorphisms (SNPs) and substance abuse on efavirenz (EFV) pharmacokinetics. 49th ICAAC, 12-15 September 2009, San Francisco. Poster abstract H-228.
http://www.posters2view.com/icaac/view.php?nu=H-228

These summaries are selected from a longer report published by this group on the Liverpool University site. All references are to
the Programme and abstracts for the 49th ICAAC, 12-15 September 2009, San Francisco.

Interactions with vicriviroc

Drug interactions with vicriviroc (30 mg alone or with RTV) were studied in HIV-negative volunteers.

There was no effect on midazolam when administered with vicriviroc alone, but there was a marked increase when administered with ritonavir. Ketoconazole increased vicriviroc AUC by 136% when administered alone and by 503% when administered with ritonavir.

There was no effect on vicriviroc exposure with rifabutin when administered with ritonavir (200 mg once daily). Rifampicin markedly decreased vicriviroc exposure when coadministered with RTV (100 mg twice daily) – the relative oral bioavailability was 11.6% based on AUC. Coadministration of rifampicin with vicriviroc is not recommended.

Carbamazepine had no effect on vicriviroc when administered with ritonavir (100 mg twice daily). In the presence of ritonavir, addition of another CYP3A4 inhibitor or modestly potent CYP3A4 inducer will not require dose adjustment of vicriviroc. If carbamazepine or rifabutin are coadministered with vicriviroc in a RTV-boosted PI-containing regimen, no vicriviroc dose adjustment is required, but ritonavir should be increased to 100 mg twice daily or 200 mg once daily.

Ref: Kasserra C et al. Assessment of pharmacokinetic and safety interactions between vicriviroc and CYP3A4 substrates, inhibitors, and inducers. Abstract H-230.

Opiate substitution therapy and antiretrovirals

Three studies provided information on the interactions between opiate substitution therapy and ARVs.

The effect of darunavir/r (600/100 mg twice daily for 7 days) on the pharmacokinetics of buprenorphine was assessed in 17 HIVnegative subjects stable on buprenorphine/naloxone maintenance therapy (daily doses up to 24/6 mg). There was no effect on buprenorphine AUC, Cmax or trough concentrations; however, norbuprenorphine Cmax increased by 36% and AUC increased by 46%. No subject required dose adjustment of buprenorphine/naloxone. Given the increase in norbuprenorphine concentrations, close clinical monitoring of patients is recommended. [1]

The effect of raltegravir (400 mg twice daily) on the pharmacokinetics of methadone were investigated in 12 HIV-negative subjects stable on methadone. This study reported that there was no change in either methadone AUC or Cmax in the presence of raltegravir and no dose adjustment is required. [2]

The interaction between buprenorphine and ddI, 3TC and tenofovir was investigated in 27 HIV-negative, buprenorphine/naloxone maintained subjects. Data for ddI and tenofovir were compared to values obtained from 20 control subjects not receiving buprenorphine; 3TC was compared to control data. No significant changes in buprenorphine pharmacokinetics were observed when coadministered with ddI, 3TC and tenofovir. When compared to controls, buprenorphine had no statistically significant effect on NRTI concentrations. [3]

References
1. Sekar VJ et al. Pharmacokinetic (PK) Interaction between darunavir in combination with low-dose ritonavir (DRV/r) and buprenorphine/naloxone (bup/nlx). Abstract H-232.
2. Anderson MS et al. Effect of raltegravir (RAL) on the pharmacokinetics (PK) of methadone. Abstract A1-1295.
3. Baker K et al. Interactions between buprenorphine and antiretrovirals: nucleos(t)ide reverse transcriptase inhibitors (NRTI) didanosine, lamivudine and tenofovir. Abstract A1-1306.

Darunavir and food

The oral bioavailability and steady state pharmacokinetics of a paediatric oral suspension of darunavir were assessed in two studies in 23 HIV-negative adult subjects. Firstly, ritonavir (100 mg twice daily) was administered on days 1-5 and a single 600 mg dose of darunavir on day 3 as a) tablet with food, b) suspension fasted, and c) suspension with food. In the second part, darunavir pharmacokinetics were assessed following administration of the suspension (600 mg twice daily) with ritonavir (100 mg twice daily) for 7 days. In the first study the criteria for bioequivalence (90% CI of LSM ratios within limits of 80-125%) were met for Cmax and AUC when comparing tablet (with food) and suspension (with or without food).

Pharmacokinetic data obtained with the suspension in the second study were comparable to historical data obtained with the same dose in the tablet formulation. The oral suspension will be further evaluated in paediatric HIV-positive subjects.

Ref: Sekar VJ et al. Bioavailability and food effect of darunavir (DRV) following administration of an oral suspension. Abstract H-233.

Raltegavir and rifabutin

Coadministration of raltegravir (400 mg twice daily) and rifabutin (300 mg once daily) was investigated in 16 HIV-negative subjects. Raltegravir AUC increased by 19%, Cmax increased by 39% and Ctrough decreased by 20%. These changes were not deemed to be clinically significant and no dose adjustment is required.

Ref: Brainard DM et al. Lack of a Clinically important effect of rifabutin (RFB) on raltegravir (RAL) pharmacokinetics. Abstract A1-1296.

Raltegavir and fosamprenavir or fosamprenavir/ritonavir

The interaction between raltegravir and atazanavir or atazanavir/ritonavir and the effect of food was studied in HIV-negative
subjects. Raltegravir (400 mg twice daily) and fosamprenavir (1400 mg twice daily) or fosamprenavir/ritonavir (700/100 mg twice daily or 1400/100 mg once daily) were administered alone and in combination with and without a light meal. The effects are summarised in Table 1 below.

Table 1. PK interactions of fosamprenavir doses with raltegravir

Although raltegravir exposure decreased with fosamprenavir, especially at higher doses of ritonavir, raltegravir Cmin were 3- to 9.4-fold higher than the IC95 for WT HIV (14.6 ng/ml). Amprenavir concentrations were decreased, however, Cmins for the boosted regimens were 2.1- to 7.8-fold higher than the EC90 for PI-naïve HIV+ patients (228 ng/ml). The clinical implications of these results have yet to be determined.

Ref: Luber A et al. Steady-state pharmacokinetics (PK) of fosamprenavir (FPV) and raltegravir (RAL) alone and combined with unboosted and ritonavir-boosted FPV Abstract A1-1297.

Etravirine and lopinavir/r

This study looked at the interaction between etravirine (200 mg twice daily) and the tablet formulation of lopinavir/ritonavir (400/100 mg twice daily) in 16 HIV-negative subjects. Coadministration decreased etravirine AUC, Cmax and Cmin by 35%, 30% and 45%, respectively; lopinavir AUC, Cmax and Cmin decreased by 13%, 11% and 20%, respectively. There was no change in the pharmacokinetics of ritonavir. These etravirine results are in contrast to previous data obtained with capsule formulation of lopinavir/ritonavir which showed increased etravirine exposure. No dose adjustment of etravirine is required as the effect of lopinavir/ritonavir tablets is similar to the effect of darunavir/ritonavir seen in clinical trials which demonstrated favourable etravirine efficacy and safety. The decrease in lopinavir concentrations was similar to earlier data and is not considered clinically relevant.

Ref: Scholler-Gyure M et al. Pharmacokinetic (PK) Interaction between etravirine (ETR) and lopinavir/ritonavir (LPV/r). Abstract A1-1298.

Etravirine and fluconazole or voriconazole

The pharmacokinetic interaction between etravirine (200 mg twice daily) and fluconazole (200 mg once daily) or voriconazole (200 mg twice daily) was studied in HIV-negative subjects. Fluconazole increased etravirine AUC, Cmax and Cmin by 86%, 75% and 2.09-fold, respectively (n=16); fluconazole AUC, Cmax and Cmin decreased by 6%, 8% and 9%, respectively (n=15). Voriconazole increased etravirine AUC, Cmax and Cmin by 36%, 26% and 52%, respectively (n=16); voriconazole AUC and Cmin increased by 14% and 23%, but Cmax decreased by 5% (n=14). Combinations were generally safe and well tolerated.

Ref: Scholler-Gyure M et al. Pharmacokinetic (PK) interaction between etravirine (ETR) and fluconazole (FLU) or voriconazole (VOR) in HIV negative volunteers. Abstract A1-1299.

LPV/r and echinacea

The effect of echinacea (500 mg three times daily for two weeks) on the pharmacokinetics of lopinavir/ritonavir (400/100 mg twice daily) was studied in 16 HIV-negative subjects. Neither lopinavir nor ritonavir pharmacokinetics were altered by coadministration of echinacea (lopinavir AUC decrease by 4% and there was no change in Cmax). Although echinacea has been shown modulate P450 3A4 in vitro, these data suggest a clinically significant interaction is unlikely.

Ref: Malati CY et al. Echinacea purpurea does not alter the steady state pharmacokinetics of lopinavir or ritonavir in healthy human volunteers. Abstract A1-1307.

“Quad” fixed-dose combination and food

A “quad” fixed dose combination tablet containing emtricitabine (200 mg), tenofovir (300 mg), elvitegravir (150 mg) and the boosting agent GS-9350 (150 mg) is currently in development. This evaluated the effects no food, or light (373 kcal, 20% fat) or high (800 kcal, 50% fat) meals on single doses of the “quad” tablet in 24 HIV? subjects. The pharmacokinetics of emtricitabine were equivalent when given fasted or with either meal. Compared to the fasting state, tenofovir AUC increased by 24% with a light meal and by 23% with a high fat meal; Cmax increase by 20% with a light meal, but was similar to fasting with a high fat meal.

Elvitegravir AUC and Cmax increased by 34% and 22% with a light meal and increased by 87% and 56% with a high fat meal (all compared to fasting). The AUC of GS-9350 was similar with a light meal, but decreased by 17% with a high fat meal (all compared to fasting).

Ref: German P et al. Effect of food on pharmacokinetics (PK) of elvitegravir (EVG), emtricitabine (FTC), tenofovir DF (TDF) and the pharmacoenhancer GS-9350 as a fixed dose combination tablet. Abstract A1-1300.

GS-9350 or ritonavir to boost atazanavir

GS-9350 is CYP3A4 inhibitor currently in development as an alternative boosting agent to ritonavir. The study compared the effects of GS-9350 (100 or 150 mg once daily) and ritonavir (100 mg once daily) on the pharmacokinetics of atazanavir (300 mg once daily) in 33 HIV-negative subjects. The higher dose of GS-9350 was found to be bioequivalent (80-125%) to 100 mg ritonavir (atazanavir GMRs of 1.01 for AUC, 0.92 for Cmax and 0.98 for Cmin). Atazanavir exposure was lower with the lower dose of GS-9350.

Ref: Ramanathan S et al. Pharmacokinetic boosting of atazanavir with the pharmacoenhancer GS-9350 versus ritonavir. Abstract A1-1301.

NVP extended release formulation

Nevirapine is licensed for twice daily administration, but is frequently given once daily. Two extended release formulation of nevirapine are currently in development. Patients who were stable on twice daily nevirapine were switch to one of two extended release formulations (XR25% and XR20%). In the 92 patients treated with XR, absorption was decreased – Tmax increased from <2h with the twice daily dosing to 6.7-8.6 h with the XR formulations. Cmin of XR formulations were comparable to the twice daily formulation, whereas Cmax of the XR formulations were lower. Relative bioavailability (based on AUC0-24) was 80% for the XR25% formulation and 71% for the XR20% formulation. No virological failures were observed. The XR25% formulation has been selected for further development due to its increased bioavailability and decreased variability compared to XR20%.

Ref: Quinson A et al. Steady state evaluation of two extended release (XR) nevirapine (NVP) tablets 400 mg QD compared with immediate release (IR) NVP tablets 200 mg BID in HIV-1 infected patients. Abstract A1-1310.

Reports from the conference

Introduction

We conclude our reports from this important conference with the following paediatric studies.

A wealth of paediatric data was presented at IAS 2009 held in Cape Town in July. Also preceding the conference was the 1st International Workshop on HIV Pediatrics, which looks as if it will become an annual fixture on the conference calendar and gave an additional opportunity to present and discuss the state of the art in the field.

Overall, far too much was presented to review here. Abstracts, some slides and, for IAS2009, webcasts can be viewed on the respective conference websites.

Several themes occurred over and over again at both meetings.

National capacity for early infant diagnosis, which not only enables early initiation of treatment but also gives a clearer picture of how well prevention of mother-to-child transmission (PMTCT) programmes are performing, with the goal of vastly reducing cases of paediatric HIV, is not yet nearly sufficient in most places.

Where infants are diagnosed in time, early initiation of treatment is not without its difficulties. It can, however, be extremely beneficial in young children.

Treatment of children who are HIV-infected despite exposure to single-dose nevirapine through PMTCT is another challenge, as is what to do in the longer term with exposed children initiated on a protease inhibitor-containing HAART to overcome the risks of NNRTI resistance.

Strategies to simplify regimens, including paediatric fixed-dose combinations and once-a-day dosing, are essential for successful management of children with HIV, as are strategies to enable co-treatment of tuberculosis in this population.

The research summarised below addresses these issues.

Several guidelines now recommend universal treatment for HIV-infected infants. However, in resource-limited settings early infant diagnosis (EID) is frequently an obstacle to early initiation of antiretrovirals.

A survey by World Health Organization (WHO) asked, “What is available for early infant diagnosis?” and found the number of laboratories in several countries mismatched to the estimated number of HIV-exposed infants and necessary tests. This assessment of national capacity was conducted to inform revisions to their guidelines for infant diagnosis and treatment. [1]

For this survey, a questionnaire on clinical and laboratory capacity was sent to HIV experts in 34 high-burden countries and data were collected between February and April 2008. Replies were received from 18 of the 34 selected countries: 12 African, two South American, two Asian and one Middle Eastern.

This revealed huge variation in the number of children assessed per laboratory (range 7 – 190 000 during the study period). When virological tests were offered, the entry points were usually inpatient/outpatient services, prevention of mother-to-child transmission (PMTCT) or antiretroviral therapy (ART) sites, and laboratories were centralised and usually located in capital cities. Six countries surveyed implement HIV DNA polymerase chain reaction (PCR), 5 RNA PCR and 7 both. Ten countries used filter paper with dried blood spots (DBS) to transport samples. All the countries that responded had capacity to measure CD4% and absolute CD4 cell counts.

Although the survey confirmed that several high-burden countries are building capacity for EID, it showed that at present in many countries capacity does not reflect estimated need.

In many resource-limited countries it is only possible to use a single diagnostic test. The optimal time to perform this is unclear, however, particularly when children are breastfed. The WHO researchers used a model to calculate the number of children becoming infected and being diagnosed at different time points from birth in order to estimate the optimal time to diagnose the maximum number of children but at the same time minimise mortality. [2]

This modelling showed a decreasing trend of infant survival at 6 months, depending on the time the test was performed. The investigators suggested that 4 – 6 weeks of age is the optimal time for infant testing in a breastfeeding population.

With greater laboratory capacity and newer technology, testing earlier than 6 weeks could mean earlier initiation of treatment. But the sensitivity of viral detection tests before 6 weeks of age is unknown, particularly when performed on infants with antiretroviral exposure for PMTCT.

A South African study looked at the sensitivity of assays at earlier time points in infants born to HIV-positive women at Rahima Moosa Hospital, Johannesburg.3 Blood was sampled at birth and at 2, 4, 6 and 10 weeks, and stored. HIV-exposed infants were routinely tested at 6 weeks with HIV DNA PCR using a liquid blood sample.

Stored DBS samples from each time point were tested with HIV DNA PCR (Amplicor v1.5), TaqMan HIV-1 (CAP/CTM) and APTIMA HIV-1 (GEN-PROBE) assays. The investigators used samples from two age-matched, PCR-negative infants as controls.

Mothers received a range of PMTCT interventions: no antiretrovirals, single-dose nevirapine (NVP), single-dose NVP plus zidovudine (AZT) or HAART.

At 9 months of the study, 253/373 (68%) infants had 6-week PCR results; the remaining 120 (32%) did not return for testing. Eighteen (7.1%) were HIV infected at 6 weeks despite the majority receiving formula milk exclusively and all receiving NVP and AZT PMTCT prophylaxis.

Of the 17 infected infants with complete results, both CAP/CTM and APTIMA assays were positive in 11/17, 13/13 and 14/14 birth, 4- and 6-week samples, respectively.

The quantitative CAP/CTM assay showed lower viral load results at 2 weeks of age (the only time point when false negatives occurred). The investigators noted that this was probably due to PMTCT prophylaxis increasing the proportional number of infants infected in utero who can therefore be diagnosed at birth.

Both assays were more sensitive for earlier HIV detection than HIV DNA PCR, which detected 9/17 birth samples. CAP/CTM had the highest specificity (100%) and HIV DNA PCR the lowest (95%).

Although this is a small sample, newer technologies appear to be more sensitive than standard PCR. These initial results suggest that the majority of in utero and perinatal infections can be detected by using either CAP/CTM or APTIMA assays if they are available.

There were also reports from programmes using DBS.

A sub-study of the PMTCT Keso Bora trial conducted in Burkina Faso used a quantitative HIV RNA assay (Biocentric) and assessed DBS samples compared with paired plasma samples obtained from HIV-exposed infants aged up to 6 weeks, 3 – 6 months and 9 – 18 months.[4] All measurements were performed locally.

The study investigators reported 100% sensitivity (102/102) and specificity (105/105) (95% confidence interval (CI) 97.2 – 100%, correlation 0.906) using DBS. Of note, Biocentric is the homebrew ANRS assay, so they would have to develop their own probes, reagents, etc.

A Cambodian study assessed the feasibility of very early diagnosis (0 – 3 days of age) using heel-prick samples on DBS and a real time DNA assay (Bicentric). [5] A second DBS was performed at week 6. Infants with positive results at 0 – 3 days or 6 weeks were followed up with HIV RNA quantification as soon as possible.

At 0-3 days, 3/370 (0.8%) infants had positive results (1 infant died before week 6). 327/333 were confirmed negative at 6 weeks and 6 were DNA positive (1.8%) and subsequently confirmed RNA positive.

The investigators suggested that these preliminary results demonstrate the feasibility of a minimally invasive very early diagnosis using DBS.

This article first appeared in issue 36 of the Journal of HIV Medicine, the journal of the Southern African Clinicians Society.

http://www.sahivsoc.org

References

Unless otherwise stated, all references are to the programme and abstracts of the 5th IAS Conference on HIV Pathogenesis, Treatment and Prevention, 19 – 22 July 2009, Cape Town.

1. Penazzato M, Crowley S. What is available for early infant diagnosis?: results from WHO survey 2008. Abstract WEPEB269.
http://www.ias2009.org/pag/Abstracts.aspx?AID=2644
2. Penazzato M, Crowley S. Early infant diagnosis in resource limited settings: determining the optimum timing in a breastfeeding population. Abstract WEPEB270.
http://www.ias2009.org/pag/Abstracts.aspx?AID=2656
3. Sherman G et al. Earlier diagnosis of HIV infection in infants in low resource settings. Abstract WEPEB267.
http://www.ias2009.org/pag/Abstracts.aspx?AID=2093
4. Gampini SE et al. Early diagnosis of paediatric HIV-1 infection among West-African breast-fed children using dried blood spots and a quantitative HIV-1 RNA assay. Abstract WEPEB264.
http://www.ias2009.org/pag/Abstracts.aspx?AID=938
5. Ngin S et al. Very early diagnosis of HIV infection in newborn at day 0-3 on DBS in Cambodia. Abstract MOPEB009.
http://www.ias2009.org/pag/Abstracts.aspx?AID=2212

A study from Swaziland, conducted by the national ART programme and the Clinton Foundation, highlighted the difficulties of treatment initiation in infants following early diagnosis. [6]

Since March 2007 the EID programme using DNA PCR was expanded in response to high infant mortality in HIV-infected children. By November 2008, however, this had led to neither an increase in infants receiving treatment nor a decrease in mortality.

The study was a retrospective record review of all infants testing positive at 15 health facilities in the Manzini Region from January to August 2008. The investigators reported that 78% of results were available at the facility, and 44% of results were documented as having been received by the caregiver. Only 58/176 (33%) of children were enrolled at an ART centre and 34 initiated on treatment. Of those with data available 81% were eligible for ART, and among eligible children, 82% initiated treatment. Overall 19% of infants testing positive were initiated on treatment at the time of the evaluation.

This study found that the greatest points of loss are return of the result to caregivers and infant enrollment at the ART centre for treatment.

This article first appeared in issue 36 of the Journal of HIV Medicine, the journal of the Southern African Clinicians Society.

http://www.sahivsoc.org

References

Unless otherwise stated, all references are to the programme and abstracts of the 5th IAS Conference on HIV Pathogenesis, Treatment and Prevention, 19 – 22 July 2009, Cape Town.

6. Sundaram M et al. Identification patient loss points from testing to treatment initiation among infants tested in Swaziland. Abstract MOPDD103.
http://www.ias2009.org/pag/Abstracts.aspx?AID=1981

There are limited data describing outcomes for infants initiating treatment at less than 1 year.

The MTCT Plus Initiative showed data from sites in eight African countries and Thailand comparing infants with older children initiated between February 2003 and September 2008. [7]

The investigators looked at change in CD4 percentage from baseline using linear modelling adjusted for duration of highly active antiretroviral therapy (HAART), country, baseline CD4 percentage, NVP exposure for PMTCT, and age at initiation.

Of 542 children initiating treatment and followed up for a median of 30 months (intraquartile range (IQR) 12 – 39), 190 (35%) were aged <12 months at initiation and the remainder >12 months (median 36 months, IQR 19.5 – 67), 51% were male, and18% had Centers for Disease Control (CDC) stage C disease.

The infants had a higher mortality rate than the older children, 7.5 v. 3.2/100 person-years. Of 31 (54%) infant deaths, 81% occurred within 3 months of treatment initiation.

Among the children for whom data were available there was no difference between infants and older children in change of CD4 percentage from baseline. Baseline CD4 percentage (p<0 .01) and time on HAART (p<0.001) were significantly associated with an increase in CD4 percentage in multivariate analysis.

In this analysis, although infants initiating HAART had a higher mortality at the start of treatment, the infants who survived had good immunological response over >3 years of follow-up, similar to that of older children.

A South African review of infants initiated on HAART at the Family Clinic for HIV at Tygerberg Hospital and Ikwezi community clinic from June 2007 to August 2008 showed high levels of virological suppression to 24 weeks. [8]

Infants received lopinavir/ritonavir (LPV/r) with stavudine (d4T) and lamivudine (3TC) in accordance with South African guidelines. Of 98 initiated, 47 had 24 weeks of follow-up. Of the remainder, 6 (6%) were lost to follow-up, 6 (6%) died and 33 (33.7%) were transferred.

The median age at initiation was 4.5 months and 33 (70%) infants were ≤6 months old (median age 3.68 months). All had immunological or clinical criteria for treatment. The majority, 42/47 (89.4%) of all infants and 30/33 (91%) ≤6 months of age, had WHO stage 3 or 4 disease.

Tuberculosis (TB) is a common co-morbidity in this population, and 11/47 infants required co-therapy with rifampicin (given with additional ritonavir).

At 24 weeks 37/47 children (79%) in the > 6 months age group and 26/33 (82%) aged <6 months had viral loads <50 copies/mL.

The investigators noted that the low age of initiation of treatment in this cohort reflected young infants with severe HIV disease rather than early initiation of treatment to prevent mortality and morbidity.

This article first appeared in issue 36 of the Journal of HIV Medicine, the journal of the Southern African Clinicians Society.

http://www.sahivsoc.org

References

Unless otherwise stated, all references are to the programme and abstracts of the 5th IAS Conference on HIV Pathogenesis, Treatment and Prevention, 19 – 22 July 2009, Cape Town.

7. Carter RJ et al. Immunologic response and survival of infants initiating antiretroviral treatment (ART) at less than one year of age compared to older children enrolled at MTCT-Plus Initiative sites in 8 African countries and Thailand. Abstract MOPEB048.
http://www.ias2009.org/pag/Abstracts.aspx?AID=2021
8. Rabie H et al. 24 week outcome of infants started on lopinavir/ ritonavir based HAART in a resource limited setting. Abstract MOPEB076.
http://www.ias2009.org/pag/Abstracts.aspx?AID=492

The developing brain is a major target for HIV. It is not yet known whether timing of initiation of antiretroviral therapy will affect neurodevelopmental outcomes in infants.

A substudy of CHER compared neurodevelopmental outcomes of 115 infants in this study from Tygerberg Children’s Hospital with 84 control infants enrolled in a linked vaccine study, CIPRASA Project4. [9]

In this prospective study, the investigators looked at the neurodevelopmental profile, according to the Griffiths Mental Developmental Scales (GMDS), at 10 – 15 months of age in four groups of infants:

• HIV-unexposed, uninfected
• HIV-exposed, uninfected
• HIV-infected, HAART initiated before 12 weeks of age
• HIV infected, HAART deferred until eligibility criteria met.

The investigators were blinded to the infants’ groups and a translator was used for Xhosa-speaking participants.

Of 115 infants from CHER enrolled, 13 withdrew from the study and/or were not co-enrolled (10 early, 3 deferred), 8 died (all deferred) and 4 were excluded (3 early, 1 deferred).

The investigators found that infants initiated on early ART have significantly better locomotor and general scores on the Griffiths Mental Development Scales at a median age of 11 months compared with infants on deferred HAART. Although mean quotients were lower on the other subscales in the deferred group, the differences were not significant. The mean scores on all subscales in the unexposed, uninfected group and the early HAART group were similar. They noted these results were “despite careful monitoring and ready access to ART in the latter” (Table I).

Table I. Mean quotients of infants for deferred vs early HAART and HIV- exposed uninfected and unexposed infants

This article first appeared in issue 36 of the Journal of HIV Medicine, the journal of the Southern African Clinicians Society.

http://www.sahivsoc.org

References

Unless otherwise stated, all references are to the programme and abstracts of the 5th IAS Conference on HIV Pathogenesis, Treatment and Prevention, 19 – 22 July 2009, Cape Town.

9. Laughton B et al. Early antiretroviral therapy is associated with improved neurodevelopmental outcome in HIV infected infants: evidence from the CHER (Children with HIV Early Antiretroviral Therapy) trial. Abstract MOPEB080.
http://www.ias2009.org/pag/Abstracts.aspx?AID=1629

Two studies looked at treatment of HIV-infected children with prior exposure to NVP to prevent MTCT.

Preliminary findings from IMPAACT 1060 confirmed concerns that NVP-exposed children could do less well receiving NVP containing HAART than protease inhibitor (PI)-containing HAART. [10, 11]

This was a randomised trial of treatment-eligible children aged 6 months – 3 years conducted in seven African countries. NVPexposed (cohort 1, n=288) and unexposed (cohort 2, n=288) children received either LPV/r or NVP, plus 3TC and AZT. Children were stratified by age <12months v. ≥12 months with an equal number to be enrolled in each age group.

A similar study of exposed and unexposed mothers had also been conducted (A5208). In this trial, the arm in which exposed mothers received NVP-containing HAART, was stopped early by the Data Safety Monitoring Board (DSMB). This was due to superior performance of the LPV/r-containing HAART arm. [12, 13]

Following a scheduled DSMB review of IMPAACT 1060 on 20 April 2009, enrolment to cohort 1 also closed prematurely owing to a trend towards consistency with the A5208 results. At 24 weeks, virological failure (<400 copies/mL) was observed in 40% of the 60 infants <12 months v. 23% ≥12 months receiving NVP and LPV/r, respectively. Among the older children, 29% out of 22 and 17% of 19 receiving NVP and LPV/r experienced failure.

Several guidelines already recommend using LPV/r-based treatment for single-dose NVP-exposed infants.

The NEVEREST study investigated whether NVP-exposed children, initially suppressed on LPV/r-based HAART, can safely switch to a NVP-based regimen. [14, 15]

In this study children aged 6 weeks – 2 years and eligible for treatment (n=323) were initiated on LPV/r plus 3TC and d4T. Children achieving a viral load <400 copies/mL and stable for ≥3 months were randomised (N=195) to either remain on LPV/r (control, n=99) or switch to NVP (switch, n=96), and then followed up to 52 weeks.

When the investigators looked at viral load <50 copies/ml to 52 weeks they found that 42.4% of children in the control group and 56.2% in the switch group sustained viral suppression (p=0.01). However, allowing for one elevated result (blip) the two groups were similar, 72.8% vs 73.4% in the control and switch groups, respectively.

They suggested that poorer adherence in the control group, due to the unpleasantness in taste of LPV/r syrup, may have led to more blipping and, in turn, unsustained viral suppression to 50 copies/mL during follow-up.

In contrast, when they looked at sustained suppression to <1 000 copies/mL, 98% v. 80% of children in the control and switch groups achieved this (p=0.001).

The investigators suggest that this study provides proof of concept that re-use of NVP is possible under some circumstances for HIV-infected children exposed to NVP prophylaxis and should be further investigated. They note that the clinical significance of low-level viraemia in the control group needs further study. This group also showed data from an evaluation of lipid profiles in children in the control and switch groups. [16]

They found no difference between the two groups at randomisation. But at 9 months after the change in regimen non-fasting total cholesterol (TC) and high-density lipoprotein (HDL) were significantly higher among the switch group (mean TC 4.13, HDL 1.36 mmol/l) compared with the control group (mean TC 3.73, HDL 1.07 mmol/l). Significantly lower triglyceride (TG) levels were found in the switch group (mean TG 1.36 mmol/l) compared with the control group (mean TG 1.53 mmol/l).

They noted that the clinical significance of these non-fasting lipid changes requires further investigation.

Switching may provide a promising option for children originally initiated on PI-based HAART to preserve second-line options. At this stage, switching requires close virological monitoring after the switch in order to be done safely.

Another NEVEREST trial of efavirenz (EFV) vs LPV/r is planned in nevirapine-exposed children >3 years old.

These studies all underscore the limited treatment options available for children, particularly in resource-limited settings.

This article first appeared in issue 36 of the Journal of HIV Medicine, the journal of the Southern African Clinicians Society.

http://www.sahivsoc.org

References

Unless otherwise stated, all references are to the programme and abstracts of the 5th IAS Conference on HIV Pathogenesis, Treatment and Prevention, 19 – 22 July 2009, Cape Town.

10. Violari A et al. Nevirapine vs. lopinavir-ritonavir-based antiretroviral therapy (ART) in single dose nevirapine (sdNVP)-exposed HIV infected infants: preliminary results from the IMPAACT P1060 trial. HIV Pediatrics, 17 – 18 July 2009, Cape Town. Abstract O_08.
http://www.hivpresentation.com/index.cfm?vID=5B52BC82-423AF6F7- C31E763DE1C6FAB7
11. Palumbo P et al. Nevirapine (NVP) vs. lopinavir-ritonavir (LPV/r)- based antiretroviral therapy (ART) in single dose nevirapine (sdNVP)-exposed HIV-infected infants: preliminary results from the IMPAACT P1060 trial. Abstract LBPEB12.
12. http:/i-base.info/htb/261
13. http://i-base.info/htb/1449
14. Coovadia A et al . Randomized clinical trial of switching to NVP-based therapy for infected children exposed to nevirapine prophylaxis. HIV Pediatrics, 17 – 18 July 2009, Cape Town. Abstract O_09.
http://www.hivpresentation.com/index.cfm?vID=5B526AE8-423AF6F7- C3840703869307AA
15. Coovadia A et al. Randomized clinical trial of switching to nevirapine-based therapy for infected children exposed to nevirapine prophylaxis. Abstract MOAB103.
http://www.ias2009.org/pag/Abstracts.aspx?AID=3746
16. Strehlau R et al. Changes in lipid profiles after switching young children from a suppressive lopinavir/ritonavir-based regimen to a nevirapine-based regimen. Abstract TUPEB166.
http://www.ias2009.org/pag/Abstracts.aspx?AID=1125

Paediatric fixed dose combination (FDC) tablets provide simpler alternatives to liquids for children.

Cipla have produced scored, dispersible tablets of d4T/3TC/ NVP (baby and junior Triomune) with the correct dose ratios for children.

A sub-study of the CHAPAS trial (Children with HIV in Africa Pharmocokinetics and Adherence of Simple Antiretroviral Regimens), in Zambia, evaluated the need for dose escalation of NVP.[17] This strategy is currently recommended but requires dosing with separate tablets, making initial treatment more complex.

Children were randomised to start antiretroviral therapy with full-dose NVP (Triomune am/pm) vs dose escalation, using an initial 14 days of half-dose NVP (Triomune am; Lamivir-S (combined d4T/3TC) pm) followed by full dose. Children were dosed in accordance with WHO weight band tables. The primary endpoint was clinical/laboratory grade 3/4 adverse events (AEs) related to NVP.

In this comparison, 211 children aged 2 – 9 years with a median CD4 percentage of 13% were followed for a median of 92 weeks. Severe stunting, wasting and immunosuppression were common in the children. Seventeen children were lost to follow-up.

The investigators reported 31(18 per 100 person-years) vs 29 (16.5 per 100 person-years) grade 3/4 AEs definitely/probably or uncertainly NVP-related in children receiving full-dose vs dose-escalation (incidence rate ratio (IRR) 1.09 (95% CI 0.63 – 1.87), p=0.74).

Twelve (11%) full-dose vs 2 (2%) dose escalation children had grade 2 disseminated skin rash and 1 receiving full dose had grade 1 rash. Two children (one from each arm) substituted with EFV; 3 continued full-dose NVP; 9 (8 full dose and 1 dose escalation) stopped NVP and restarted with successful dose escalation; and 1 full dose stopped, started a lower NVP dose, had another rash and substituted EFV.

Overall 90% of children who started with full-dose NVP continued uninterrupted in this study. As dose escalation requires provision of separate drug formulations, the evaluation of policy implications for dose escalation of NVP in fixed-dose combination HAART is ongoing.

The CHAPAS trial also investigated the pharmacokinetics of NVP in children treated with Triomune Baby/Junior and rifampicinbased tuberculosis treatment. [18]

EFV-based regimens are currently recommended for concomitant use with rifampicin, but EFV is not currently indicated for children below 3 years of age. Earlier CHAPAS data suggest that the higher dose ratio of NVP to NRTI in Triomune Baby/Junior may compensate for the dose reduction induced by rifampicin.

Pharmacokinetic sampling was performed in 22 children after 4 weeks of concurrent NVP and rifampicin-containing regimens. Rifampicin was dosed at 10 – 20 mg/kg per day. Samples were pre-dose (C0) and 1, 2 and 6 hours post-dose, and nevirapine plasma concentrations were determined using LC-MS/MS. NVP pharmacokinetics in children without TB treatment (n=16) were compared in multivariate linear regression analysis. The median age of the 21 children analysed was 1.55 (range 0.66 – 3.18) years, and 10 were girls.

The investigators found that only 11 (52%) of the children receiving TB treatment reached sufficient NVP trough levels (C0 <3.0 mg/L). Multvariate analysis revealed a 41% (95% CI 24 – 55%) reduction in nevirapine AUC with concomitant rifampicin. They noted a 3.4% increase in AUC for each 10 mg/m2 increase in NVP dose/m2.

They recommend caution with this approach in young children until more efficacy and safety data are available. They suggest that an increased NVP dose is likely to be necessary and requires further evaluation.

This article first appeared in issue 36 of the Journal of HIV Medicine, the journal of the Southern African Clinicians Society.

http://www.sahivsoc.org

References

Unless otherwise stated, all references are to the programme and abstracts of the 5th IAS Conference on HIV Pathogenesis, Treatment and Prevention, 19 – 22 July 2009, Cape Town.

17. Kabamba D et al. Strategies for nevirapine initiation in HIV-infected children taking paediatric fixed-dose combination ‘baby pills’ in Zambia: a randomised controlled trial. Abstract MOPEB090.
http://www.ias2009.org/pag/Abstracts.aspx?AID=3011
18. Oudijk JM et al. Pharmacokinetics of nevirapine in young children during combined ART and rifampicin-containing antituberculosis treatment. Abstract LBPEB10.
http://www.ias2009.org/pag/Abstracts.aspx?AID=3715

Simplification of HAART regimens provides benefit for children, caregivers and health workers. To date there are no data on oncedaily use of 3TC and abacavir (ABC) in resource limited settings.

A substudy from the ARROW trial (a randomised trial of monitoring and first-line induction-maintenance strategies) compared the PK of once- v. twice-daily 3TC and abacavir (ABC) (Kivexa).[19] This was a cross-over study performed in 41 Ugandan children aged 3 – 12 years receiving HAART, dosed according to weight bands. The ARROW trial uses scored tablets of ABC/3TC to ensure better accuracy of division and more flexible dosing. Total daily doses were 150+300 mg, 225+450 mg and 300+600 mg for children weighing 12 – 20 kg, 20 – 25 kg and >25 kg, respectively.

PK sampling was performed for twice-daily dosing at steady state (36 weeks) pre-dose, and 1, 2, 4, 6, 8 and 12 hours post dose. Children were then switched to the once-daily dose and further sampling was performed at 4 weeks with an additional sampling at 24 hours.

Daily area under the curve (AUC0-24) and peak level (Cmax) were compared by geometric mean ratios (GMR). GMR with 90% CI within 0.80 – 1.25 was considered to be bioequivalent.

PK parameters were available for 35 and 36 children for 3TC and ABC, respectively. Approximately half were in the younger age group.

The investigators reported that in children 3 – 12 years, AUC0-24 of both 3TC and ABC were bioequivalent with once and twice daily regimens but Cmax was 76% and 64% higher for 3TC and ABC respectively. No grade 3/4 adverse events were reported and no child discontinued after the switch to once-daily dosing.

In this analysis, in contrast to data from European children in PENTA 13, 3TC AUC levels in 3 – 6- and 7 – 12-year-old children were similar for both once- and twice-daily dosing and similar to levels in older children. The investigators noted that many younger children in PENTA 13, whose 3TC levels were lower, received syrups, but ARROW children received tablets. They concluded that these results suggest that once-daily dosing of 3TC and ABC is feasible in resource-limited settings.

The ARROW investigators also showed data describing successful management of hypersensitivity reactions among children in this trial in Uganda and Zimbabwe.[20]

The WHO recommends ABC for paediatric first-line treatment. Hypersensitivity reactions (HSR) occur in 2 – 5% of people receiving ABC in clinical trials and are strongly associated with the presence of the HLA-B*5701 allele. Prospective screening for HLA-B*5701 is sometimes recommended, but this pharmacogenetic test is rarely available in resource limited settings.

Clinical diagnosis and management may be complicated in this setting due to widespread use of NVP and cotrimoxazole and febrile infections.

Health workers and caregivers were trained in recognition and management of ABC-HSR and all suspected HSR underwent independent clinical review. ABC was only discontinued in 7 cases.

The investigators reported that suspected ABC-HSR was rare (3/1 207, 0.2% (95% CI, 0.05 – 0.7%)) in this trial, consistent with reports of a lower prevalence of HLA-B*5701 in black populations. Clinical symptoms (fever, rash) occurred 9 – 13 days after initiation of HAART; 2/3 cases had additional gastrointestinal and respiratory symptoms and required hospitalisation.

ABC-HSR was successfully managed despite co-administration of cotrimoxazole and NVP, and the investigators recommend that ABC can be used safely in resource-limited settings.

This article first appeared in issue 36 of the Journal of HIV Medicine, the journal of the Southern African Clinicians Society.

http://www.sahivsoc.org

References

Unless otherwise stated, all references are to the programme and abstracts of the 5th IAS Conference on HIV Pathogenesis, Treatment and Prevention, 19 – 22 July 2009, Cape Town.

19. Musiime V et al. Pharmacokinetics of once versus twice daily lamivudine and abacavir in HIV-1 infected Ugandan children in the ARROW trial. Abstract WEPEB271.
http://www.ias2009.org/pag/Abstracts.aspx?AID=1594
20. Nahirya-Ntege P et al. Successful management of suspected abacavir hypersensitivity reactions among African children in the ARROW (AntiRetroviral Research for Watoto) trial. Abstract TUPEB183.
http://www.ias2009.org/pag/Abstracts.aspx?AID=1737

Reports from the conference

For the first time, web casts of several sessions are available via the conference website together with searchable online abstracts and PDF files of many or the posters or presentations

http://www.ias2009.org

The abstract database from the meeting is online at the same site.

In this issue we include the following articles:

• Overview of ARV studies at IAS
  • First results of new integrase compound: GSK1349572
  • Raltegravir in treatment naive-patients
  • Nevirapine vs atazanavir/ritonavir in treatment-naive patients: the ARTEN study
  • Darunavir/r monotherapy studies
  • Maraviroc results similar to efavirenz when analysed using more sensitive tropism test
• Lipid and metabolic changes with ARV combinations
• Maximal suppression achieved with three drugs: no additional virological impact of raltegravir intensification
• Tenofovir and renal safety
• Time from seroconversion to treatment in Europe and Africa
• Pharmacokinetics of atazanavir/ritonavir during pregnancy
• Presentation with late stage HIV in women diagnosed during pregnancy
• Low transmission rates and favourable pregnancy outcomes reported in the DREAM study
• Pregnancy rates and outcomes among women in the DART trial</