Intrapartum and neonatal single-dose nevirapine compared with zidovudine for prevention of mother-to-child transmission of HIV-1 in Kampala, Uganda: 18-Month follow-up of the HIVNET 012 randomised trial

Background: In 1999, we reported safety and efficacy data for short-course nevirapine from a Ugandan perinatal HIV-1 prevention trial when 496 babies were followed up to age 14-16 weeks. Safety and efficacy data are now presented for all babies followed up to 18 months of age. Methods: From November, 1997, to April, 1999, HIV-1 infected pregnant women in Kampala, Uganda, were randomly assigned nevirapine (200 mg at labour onset and 2mg/kg for babies within 72 h of birth; regimen A) or zidovudine (600 mg orally at labour onset and 300 mg every 3 h until delivery, and 4 mg/kg orally twice daily for babies for 7 days, regimenB). Infant HIV-1 testing was done at birth, age 6-8 and 14-16 weeks, and age 12 months by HIV-1 RNA PCR, and by HIV-1 antibody at 18 months. HIV-1 transmission and HIV-1-free survival were assessed using Kaplan-Meier analysis. We recorded adverse experiences through 6-8 weeks postpartum for mothers, and 18 months for babies. Efficacy analyses were by intention to treat. Findings: We enrolled 645 mothers to the study: 313 were assigned regimen A, 313 regimen B, and 19 placebo. Eight mothers were lost to follow-up before delivery. 99% of babies were breastfed (median duration 9 months). Estimated risks of HIV-1 transmission in the zidovudine and nevirapine groups were 10·3% and 8·1% at birth (p=0·35); 20·0% and 11·8% by age 6-8 weeks (p=0·0063); 22·1% and 13·5% by age 14-16 weeks (p=0·0064); and 25·8% and 15·7% by age 18 months (p=0·0023). Nevirapine was associated with a 41% (95% CI 16-59) reduction in relative risk of transmission through to age 18 months. Both regimens were well-tolerated with few serious side-effects. Interpretation: Intrapartum/neonatal nevirapine significantly lowered HIV-1 transmission risk in a breastfeeding population in Uganda compared with a short intrapartum/neonatal zidovudine regimen. The absolute 8·2% reduction in transmission at 6-8 weeks was sustained at age 18 months (10·1% [95% CI 3·5-16·6]). This simple, inexpensive, well-tolerated regimen has the potential to significantly decrease HIV-1 perinatal transmission in less-developed countries.