Researchers at the National Institutes of Health (NIH) have found that the antiretroviral drugs, dolutegravir and emtricitabine/tenofovir alafenamide fumurate (DTG+FTC/TAF), may comprise the safest and most effective HIV treatment regimen currently available during pregnancy. The findings come from a multinational study of more than 640 pregnant women with HIV across 4 continents.

Previous research has demonstrated that antiretroviral therapy (ART) to suppress HIV prevents perinatal transmission of the virus and benefits the health of both mother and child. In the current study, 3 ART regimens were compared, showing that the regimens containing DTG were more effective in suppressing HIV than a commonly used regimen containing efavirenz (EFV).

IMPAACT 2010 or VESTED (Virologic Efficacy and Safety of Antiretroviral Therapy Combinations with TAF/TDF, EFV and DTG) is a phase 3 clinical trial that randomly assigned 643 women to begin HIV treatment 14-28 weeks into their pregnancies with EFV/FTC/TDF or 2 newer regimens: DTG+FTC/TAF and DTG+FTC/TDF.

EFV/FTC/TDF is formulated as a single tablet, whereas the newer regimens consist of a DTG tablet taken with a combined FTC/TAF or FTC/TDF tablet. Nearly 98% of women who received either of the DTG-containing regimens were virally suppressed at the time of delivery, meaning their viral load was undetectable using standard tests, according to the researchers.

Furthermore, 91% of women who received EFV/FTC/TDF were virally suppressed at delivery. Two infants were diagnosed with HIV within 14 days of birth, with each of the groups receiving DTG-containing regimens. The research team is currently investigating data on medication adherence and drug levels at the time of delivery.

The researchers found that 24% of women taking DTG+FTC/TAF had an adverse pregnancy outcome compared with 33% of women taking DTG+FTC/TDF or EFV/FTC/TDF. The rates are consistent with adverse pregnancy event rates in low- and middle- income countries where most of the participants live, including pregnancy complications of preterm delivery, low infant birth weight based on gestational age, and stillbirth.

The results show that although all 3 regimens are safe and effective in pregnancy, HIV is better controlled by DTG-containing regimens, and DTG+FTC/TAF may lead to lower adverse pregnancy outcomes. The findings affirm World Health Organization recommendations for use of DTG in pregnant women.

“These findings include the first of many insights we hope to glean from the VESTED study,” said Lameck Chinula, MBBS, MMed,co-chair of VESTED, in a press release. “My fellow researchers and I extend our heartfelt thanks to the study volunteers. Each played a vital role in supporting the wellbeing of women and babies around the world.”

Newer anti-HIV drugs safest, most effective during pregnancy. NIH. Published March 11, 2020. Accessed March 19, 2020.