Antiretroviral therapy lowers mother-to-child HIV transmission rates

1. Rates of HIV transmission were significantly lower for two combined antiretroviral therapies (ART) compared to single drug zidovudine prophylaxis.

2. Combined ART was associated with higher rates of maternal and neonatal adverse outcomes compared to single drug treatment.

Evidence Rating: 1 (Excellent)

Study Rundown: Pregnant women with HIV are treated with antiretroviral therapies to both treat their condition and reduce the likelihood of HIV transmission to their child. Regimens used include single drug as well as combined ART. While HIV transmission is thought to be reduced to a greater extent with combined ART, some evidence suggests single drug treatment results in fewer pregnancy related complications and adverse outcomes. This study looked to compare various established combined ART regimes to single drug prophylaxis on the basis of both HIV transition rates and adverse outcomes.

The primary outcome in the study was HIV transmission rates, and the secondary outcome was adverse events. The study revealed that combined ART reduced transmission rates compared to zidovudine alone. Maternal adverse outcomes were more common in the zidovudine-ART group comparted to the zidovudine group. Both zidovudine and tenofovir ART groups had higher rates of adverse pregnancy outcome relative to the zidovudine group.

Click to read the study, published today in NEJM

Relevant Reading: Early antiretroviral therapy and mortality among HIV-infected infants

In-Depth [randomized controlled trial]: Between 2011 and 2014, 3529 HIV positive mother-infant sets were recruited from 7 African and south Asian countries. Expecting mothers were included in the study if they had >350 CD4 cells/mm³, were at 14 or more weeks of gestation, did not have active TB, were never treated for HBV, and met other inclusion/exclusion criteria. Women were randomized in 3 groups: zidovudine alone, zidovudine-based ART (zidovudine, lamivudine, and lopinavir-ritonavir), or tenofovir-based ART (tenofovir, emtricitabine, and lopinavir-ritonavir). Patients were on these regimens from study enrollment to 1-week post-partum. Maternal study visits were conducted throughout the pregnancy to perform blood analysis and test for HIV transmission at 1-week post-partum. Adverse outcome for both mothers and children were assessed using the DAIDS Table for Grading the Severity of Adult and Pediatric Adverse Events.

HIV transmission rates were significantly lower in the ART groups (both groups analyzed together) compared to zidovudine alone (0.5% vs. 1.8%; difference −1.3 percentage points; repeated CI −2.1 to −0.4). HIV-free survival through week 1 of life was significantly higher with zidovudine-based ART (p = 0.001) compared to zidovudine alone or tenofovir-based ART compared to zidovudine (p = 0.002). Women on zidovudine-based ART and tenofovir-based ART had more adverse pregnancy outcomes than those on zidovudine alone (zidovudine ART vs zidovudine, 40% vs 27.5%, p < 0.001; tenofovir ART vs zidovudine, 34.7% vs 27.2%, p = 0.04). The tenofovir-based ART group had more severe pregnancy outcomes compared to the zidovudine-based ART group (9.2% vs 4.3%, p = 0.02). Very preterm deliveries were more common for tenofovir-based ART compared to zidovudine-based ART groups (6% vs 2.6%, p = 0.04). Women discontinued the regimens at similar nonsignificant rates in all three groups (2-5%).

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