Addition of Single-dose, Maternal Tenofovir and Emtricitabine to Reduce Non-nucleoside Reverse Transcriptase Inhibitor Resistance Mutations in the Setting of Zidovudine and Nevirapine for Prevention of Mother-to-child HIV Transmission

Single-dose intrapartum and neonatal nevirapine (NVP), either alone or in combination with short course zidovudine (ZDV) is in widespread use to prevent mother-to-child HIV transmission throughout the developing world. Though the public health benefits cannot be overstated, widespread use of NVP in this fashion may come at a cost. Non-nucleoside reverse transcriptase inhibitor (NNRTI) resistance mutations are induced in at least 20% and probably a larger proportion of women exposed to NVP in this fashion. Addition of short-course ZDV does not appear to mitigate this effect substantially. The full implications of these NVP resistance mutations are yet unknown, though there is concern that they may result in reduced efficacy of the NVP or other NNRTIs in long-term, therapeutic regimens.

We are conducting a clinical trial of tenofovir (TDF) and emtricitabine (FTC), marketed as a fixed dose combination, Truvada ™, to reduce NNRTI-resistance post-delivery in the setting of NVP with or without ZDV for PMTCT. TDF and FTC are both Category B drugs and are approved for use in pregnancy. They have several characteristics that make them ideal candidate drugs for use in conjunction with NVP, including long intracellular half-lives and established safety profile among adults for HIV treatment.

Women will be enrolled between 28 and 38 weeks of gestation. As part of normal PMTCT services, they may choose NVP-boosted ZDV or single dose NVP for PMTCT; We anticipate that most (~80%) will choose the former. At arrival for delivery, they will be randomized to receive either the two study drugs (intervention) or no drug (control). A total of 400 women will be randomized, and followed, along with their infants, for 6 months.