Atazanavir in pregnancy: 155 cases in London clinics

Polly Clayden, HIV i-Base

Atazanavir is increasingly used in pregnancy. There are limited data to guide this use.

In an oral presentation at the spring 2011 BHIVA meeting Miriam Samuel presented data from a retrospective case note review of atazanavir-exposed pregnancies at 12 London sites.

The review included 155 pregnancies in 145 women since December 2004.

The majority (118, 71.6%) of women were Black African and a small proportion were IDUs (5, 3.2%). Their median age was 32 years (15–47), 6 were Hepatitis B and 2 Hepatitis C co-infected. Only 15 (9.7%) were diagnosed this pregnancy and 105 (68%) were receiving HAART when they conceived. Their median CD4 was 401 cells/mm3 (range15–1161 cells/mm3).

Over half (93, 60%) conceived while receiving ATV; 20% of the remainder changed from another drug and 20% started with ATV first line in pregnancy. Only 9% of women received AZT and 16% abacavir but 72% received tenofovir as part of their nucleoside backbone.

Overall, atazanavir was well tolerated with 98/155 (63.2%) reporting no side effects. The commonest side effect was nausea, which was reported by 53/155 (34.2%) of women. Only 3/155 (1.9%) of women discontinued ATV due to side effects.

Of 21 women who switched to atazanavir due to GI side effects from a previous regimen (20 PI based), symptoms improved in 19. One woman stopped atazanavir due to persistent nausea.

There was a low overall incidence of hepatotoxicity; 9 (5.8%) women developed G1-4 raised transaminase. Of these, 5 women switched to atazanavir with pre-existing hepatotoxicity,1 from nevirapine and 4 from lopinavir/r. LFTs resolved in 3 women and 2 had persistent hepatotoxicity and ATV was discontinued in both cases.

Of the 130 women with viral load data available, 104 (80%) had <50 copies/mL at delivery. As would be expected, of the subset that started atazanavir in pregnancy (n=25), the proportion with an undetectable viral load increased with time on treatment: 29% and 72% with <12 and >12 weeks of HAART respectively.

Of the 133 deliveries with data available, 64 (48%) were by elective caesarean, and half the remainder by vaginal delivery and the other half emergency caesarean (both 26%). Pre-term delivery <37 weeks occurred in 13/130 infants (10%).

The 94 infants with neonatal bilirubin measured had a median 71umol/L(range 3-258 umol/L). Three neonates had phototherapy; 1 polycythaemic (bilirubin 258 umol/L); 1 infant haemolytic anaemia (bilirubin 109 umol/L) and 1 no other cause (bilirubin 194 umol/L). There was 1 congenital cardiac abnormality.

There was only one transmission, reported to be in utero, to a mother with a history of poor adherence.

The investigators concluded from this case series (the largest to date) that atazanavir is well tolerated in pregnancy with low toxicity and discontinuation rates. This applied to women conceiving on atazanavir, starting in pregnancy or switching. The infant safety data are reassuring.


Data on atazanavir PK during pregnancy at the PK Workshop, from the IMPAACT investigators in the US, reported in this issue of HTB, suggest that the dose of ATV/r should be increased to 400/100mg during the third trimester and the same considered during the second. The dose used in this study was 300/100 mg for the majority of the 149/155 women who received ATV boosted.

Currently, in the UK, most caregivers of pregnant women stick to the standard dose and some use TDM. However in this cohort only 17 women had routine third trimester TDM and 11 because of elevated viral load, despite it being available (though some don’t think it is evidence based or cost effective). Although the third trimester levels in patients on tenofovir might be of concern, these investigators do not report treatment failure.

In this study women who conceived on HAART did very well and did not loose virological control in the third trimester.

The 80% rate with <50 copies/mL at delivery among women initiating HAART in pregnancy improved with longer duration of treatment, as would be expected.

This case note review goes back to 2004, so a good proportion of women will have been treated prior to last years report emphasising the importance of earlier initiation of HAART in pregnancy at higher viral loads to ensure viral suppression and in turn greater choice over mode of delivery.


Samuel M et al. Atazanavir in pregnancy: a report of 155 cases. 17th Annual BHIVA Conference, 6–8 April 2011, Bournemouth. Oral abstract O25.

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