Taking a three-drug regimen during pregnancy prevented mother-to-child HIV transmission more effectively than taking one drug during pregnancy, another during labor, and then two more after giving birth, according to results of an ongoing international clinical trial. This study is being conducted by The International Maternal Pediatric Adolescent AIDS Clinical Trials (IMPAACT) network with funding from NIAID and NICHD.

The PROMISE (Promoting Maternal-Infant Survival Everywhere) study began in 2010 to determine how best to safety lower the risk of HIV transmission from infected pregnant women to their babies during pregnancy and post-delivery. The study also aimed to examine how discontinuing vs. continuing a three-drug anti-HIV regimen after breastfeeding impacts mother with good immune health.

Over 3,500 pregnant or postpartum women infected with HIV who did not meet national critiera for receiving anti-HIV treatment, as well as over 3,200 HIV-exposed infants of these women in India, Malawi, South Africa, Tanzania, Uganda, Zambia, and Zimbabwe were enrolled in the study. Two proven regimens were compared for greater safety and efficacy:

  • Zidovudine as early as 14 weeks into the pregnancy + single dose of nevirapine during labor + tenofovir and emtricitabine for two weeks after delivery (Option A); or
  • One of two triple anti-HIV drug regimens as early as 14 weeks into the pregnancy – lamivudine, zivovudine and lopinavir/ritonavir; or tenofovir, emtricitabine, and lopinavir/ritonavir (Option B and Option B+).

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The study found that there was a significantly lower rate of of maternal-infant HIV transmission during pregnancy or delivery among women in the three-drug regimen group vs. those who received Option A. Among mothers who received the lamivudine combination, only 0.5% of infants became infected with HIV, 0.6% of infants among mothers who received the tenofovir combination, compared to 1.8% of infants among mothers who received Option A.

It was also concluded that the lamivudine combination was safer in comparison to the other regimens. Lower rate of severe adverse pregnancy outcomes (eg, very low birth weight, very premature delivery, still birth, spontaneous abortion, major birth defects) were seen in the lamivudine combination group vs. the tenofovir combination group. There were also fewer deaths within two weeks of birth in babies whose mothers received the lamivudine combination vs. the tenofovir combination.

These interim findings further support the World Health Organization (WHO) guidelines for preventing mother-to-child HIV transmission. The study will continue as originally designed and follow the women and children until two years after the last child is born.

For more information visit NIH.gov.