Lamivudine-Zidovudine Combination for Prevention of Maternal-Infant Transmission of HIV-1

A two-thirds reduction in mother-infant HIV-1 transmission has been achieved using zidovudine alone. Antiretroviral drug combinations are increasingly used today; this study was an attempt to document the effectiveness and safety of perinatal lamivudine-zidovudine therapy in an open-label, nonrandomized trial conducted at 48 sites in France. Participants were 445 pregnant women infected by HIV-1 who received the drug combination during 1997–1998 and 899 pregnant women who had received zidovudine alone as standard treatment during 1994–1997. In addition to standard zidovudine prophylaxis, women in the study group received 150 mg of lamivudine therapy twice daily, orally, from 32 weeks’ gestation through delivery. Infants subsequently received 2 mg/kg of this drug twice a day for 6 weeks. Zidovudine was started at a median of 23 weeks’ gestation and continued for a median of 15 weeks; the drug was almost always given intravenously.HIV infection was diagnosed in seven infants in the study cohort (1.6%). Transmission was not significantly less frequent with elective cesarean delivery. In the control group the maternal-infant transmission rate was 6.8%, significantly higher than in the study cohort. A 5-fold reduction persisted in the latter group after adjusting for mode of delivery, pervious antiretroviral therapy, and progression of maternal HIV disease. Nearly three-fourths of women in the study group had a plasma HIV-1 RNA level below 500 copies/ml at the time of delivery. Nine children had neutropenia or anemia requiring blood transfusion, and treatment was discontinued prematurely in 19 instances.It seems possible to lower the risk of maternal-infant HIV-1 transmission by adding lamivudine to zidovudine prophylaxis in the third trimester of pregnancy, but the resultant benefit must first be compared with the incremental risk.