In this phase 1-2 trial involving HIV-1-infected children, an age of three months or younger at the initiation of therapy and treatment with stavudine, lamivudine, nevirapine, and nelfinavir were associated with improved long-term viral suppression. Larger, randomized trials are required to define the optimal time to initiate therapy and the optimal regimen for these infants.

There were no identified problems that would alter current recommendations for the routine use of ZDV for the prevention of mother-child HIV-1 transmission.

Pediatric AIDS Clinical Trials Group protocol 316 was an international, multicenter, placebo-controlled trial comparing single-dose oral nevirapine (200 mg to mother and 2 mg/kg to infant) with placebo in human immunodeficiency virus (HIV)-infected pregnant women receiving standard antiretroviral therapy. This substudy evaluated the emergence of nevirapine-resistance mutations at 6 weeks postpartum in a subgroup of participants. Maternal risk factors for the emergence of nevirapine-resistance mutations were evaluated. Mutations associated with nevirapine resistance were detectable at delivery, prior to receipt of study drug, in 5 (2.3%) of 217 women. Fourteen (15%; 95% confidence interval, 8%-23%) of 95 women who received intrapartum nevirapine developed a nevirapine-resistance mutation 6 weeks postpartum. The most common mutation was K103N, which was present in 10 women. The risk for development of a new nevirapine-resistance mutation did not correlate with CD4 cell count or HIV-1 RNA load at delivery or with type of antepartum antiretroviral therapy. The risk of nevirapine resistance should be considered when determining the risks or benefits of intrapartum nevirapine in women receiving antepartum antiretroviral therapy.

Maternal samples were assessed from 96 women enrolled in Pediatric AIDS Clinical Trials Group protocol 076 to determine the prevalence of human immunodeficiency virus type 1 (HIV-1) genotypic zidovudine resistance at entry, if zidovudine resistance developed on study, and the role of zidovudine resistance in vertical transmission of HIV-1 despite zidovudine therapy. Low and high levels of genotypic resistance were assessed by differential hybridization, oligoligation, or direct sequencing of plasma HIV-1 RNA for codons K70R and T215Y/F. None of the women had high-level genotypic resistance to zidovudine at study entry or delivery. For low-level zidovudine resistance, the 95% confidence intervals were 0.3%-6.8% for baseline prevalence and 0.3%-14% for delivery incidence. Low-level zidovudine resistance, adjusted for plasma viral RNA level at delivery, was not strongly associated with an increase in vertical transmission risk (odds ratio, 4.8; 95% confidence interval, 0.2-131; P = .35).

A once-daily regimen of emtricitabine, didanosine, and efavirenz proved to be safe and tolerable and demonstrated good immunologic and virologic efficacy in this 2-year study.