HIV-positive women who take a boosted protease inhibitor plus Combivir (zidovudine/lamivudine) have birth outcomes comparable to those who take a boosted protease inhibitor plus Truvada (tenofovir disoproxil fumarate/emtricitabine), Infectious Disease Advisor reports. However, if the recent study that reached this conclusion had included more data on such outcomes, it may have been able to detect such differences.

Publishing their findings in The New England Journal of Medicine, researchers analyzed data from two U.S.-based cohort studies that compared the risk of adverse birth outcomes among infants exposed in utero to Combivir plus Kaletra (lopinavir/ritonavir), Truvada plus Kaletra, or Truvada plus Norvir (ritonavir)-boosted Reyataz (atazanavir).

Kaletra and Reyataz are both protease inhibitors. Norvir, which is included in Kaletra, is a boosting agent used to raise the level of HIV treatments in the body.

Looking at 4,646 birth outcomes, the investigators analyzed the risk of preterm birth (an infant born before 37 weeks of gestation), very preterm birth (an infant born before 34 weeks of gestation), low birth weight (less than 2.5 kilograms, or 5.51 pounds) and very low birth weight (less than 1.5 kg, or 3.31 lbs).

Just 2.8 percent (128) of the infants were exposed to Truvada plus Kaletra as the initial regimen their mothers took while pregnant with them. A total of 11.6 percent (539) of the infants were exposed to Truvada plus Norvir-boosted Reyataz, and 20.5 percent (954) were exposed to Combivir plus Kaletra.

Compared with women who received Combivir plus Kaletra, those who received Truvada plus Kaletra had similar risks of preterm birth and low birth weight. Compared with women who received Truvada plus Norvir-boosted Reyataz, women who received Truvada plus Kaletra had a 14 percent increased risk of preterm birth and a 45 percent increased risk of low birth weight. However, neither of these two increased risks was statistically significant, meaning they may have been driven by chance.

The study authors concluded: “The risk of adverse birth outcomes was not higher with [Truvada plus Kaletra] than with [Combivir plus Kaletra] or [Truvada plus Norvir-boosted Reyataz] among HIV-infected women and their infants in the United States, although power was limited for some comparisons.”

To read the Infectious Disease Advisor article, click here.

To read the study abstract, click here.