No impact of HSV-2 suppressive therapy on HIV incidence

Deborah Watson-Jones, from the London School of Hygiene & Tropical Medicine presented data from a study to evaluate the impact of suppressive HSV-2 treatment on HIV incidence among women at high risk of infection in northern Tanzania.

Acyclovir has been shown in recent studies to reduce genital shedding of HIV in women co-infected with HIV and HSV-2.

This was a randomised, double-blind, placebo-controlled trial of acyclovir (400 mg BD) among initially HIV-negative/HSV-2 positive women. Women working in bars, guesthouses and similar facilities attending mobile clinics were followed for a maximum of 30 months.

Clinic visits were every 3 months women received safe sex counseling, condoms, routine health checks, STI treatment and were offered VCT.

821 HIV-seronegative women were enrolled in three phases and randomised to acyclovir (n=400) or placebo (n=421). 216 (26%) withdrew from study tablets, mainly because of pregnancy (79%).

Dr Watson Jones reported that in an intent-to-treat analysis: 316 (75%) and 280 (70%) of women completed follow-up (FU) – with 72 (17%) and 90 (23%) lost – in the placebo and acyclovir arms respectively. There were 33 (8%) seroconversions in the placebo arm and 30 (80%) in the acyclovir arm. This gave 777 and 699 person years of FU and an HIV incidence rate/100 person years of 4.25 (3.6-6.0) and 4.29(3.00-6.1), rate ratio1.01 (0.61-1.66), in the placebo and acyclovir arms.

The investigators suggested that these disappointing results could be associated with poor adherence; in on-treatment analysis by adherence they reported a rate ratio of 0.58 (0.3-1.4) of >/= 90% adherence.

They concluded that there was No effect of acyclovir on HIV incidence but proof of concept may require a higher level of adherence.

Watson-Jones D, Rusizoka M, Weiss H et al. Impact of HSV-2 suppressive therapy on HIV incidence in HSV-2 seropositive women: a randomised controlled trial in Tanzania. 4th IAS conference, Sydney, 2007. Oral abstract MOAC104.