12th Annual Conference of the British HIV Association 29 March–1 April 2006, Brighton, UK

DOES ZIDOVUDINE MONOTHERAPY (MZDV) IN PREGNANCY PREDISPOSE TO THE EMERGENCE OF RESISTANCE?

HIV Med 2006; 7(Suppl. 1):2 (abstract no. O5)

Phillip Read¹, Sinead Costelloe², Jane Mullen², Siobhan O’Shea², Fiona Lyons¹, Phillip Hay³, Jan Welch⁴, Nick Larbalestier¹, Graham Taylor⁵ and Annemiek de Ruiter^1
1Department of Genitourinary Medicine, Guy’s & St Thomas’ NHS Foundation Trust, London, ²Department of Infection, Virology Section, Guy’s and St Thomas’ NHS Foundation Trust, ³Department of Genitourinary Medicine, St George’s Hospital, ⁴Department of Genitourinary Medicine, King’s College Hospital, ⁵Department of Genitourinary Medicine, St Mary’s Hospital, London, UK

AIMS: BHIVA guidelines recommend antenatal mZDV as an option in certain scenarios in pregnancy [baseline viral load (BVL) <20000 copies/ml, 2001 guidelines; <10000 copies/ml 2005 guidelines]. Concerns for evolution of resistance prompted this study to determine the incidence of resistance following mZDV exposure.

METHODS: Retrospective review of women receiving mZDV in pregnancy with a BVL of <20000 copies/ml in four hospitals. Demographic and clinical parameters were collected. Genotyping of samples nearest delivery was performed using population-based sequencing (Trugene HIV-1, Bayer and ViroSeq v2.6 Celera/ ABi). A subgroup of samples was also examined for drug-resistant minority species using cloning technology (Zero Blunt TOPO, Invitrogen).

RESULTS: Fifty-six women had samples available for analysis; 17 had <50 copies/ ml off therapy and could not be genotyped; eight failed to amplify and 48 were sequenced successfully. Of these 48 women, median age was 30 years (19–40); 36 (75%) were Black Africans; 44 (92%) infected with non-B subtypes. Median pre-treatment HIV viral load (VL) and CD4 counts were 2101 copies/ml (285–14900) and 410 × 10⁶/l (228–958) respectively. Median delivery VL was 1664 copies/ml (78–27930) and median duration of mZDV exposure was 11 weeks (3–21). No ZDV-associated mutations were detected by population- based sequencing (n=48) and no drug-resistant minority species were detected by cloning (n=13). There were no vertical transmissions in the cohort (n=73).

CONCLUSIONS: Results to date from this cohort support the strategy of selective mZDV in preventing MTCT of HIV-1 without the development of significant resistance.

2006-03-29
O5

Copyright © 2006 - British HIV Association (BHIVA) Reproduction of this abstract (other than one copy for personal reference) must be cleared through the BHIVA Organising Secretariat 1 Mountview Court, 310 Friern Barnet Lane, London N20 0LD