Drug Combo Can Reduce Risk of Perinatal HIV in High-Risk Infants

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Drug Combo Can Reduce Risk of Perinatal HIV in High-Risk Infants

LOS ANGELES -- June 20, 2012 -- A study published June 21 in the New England Journal of Medicine finds that a 2- or 3-drug combination given to infants born to HIV-positive mothers within 48 hours of birth can reduce the risk of intrapartum HIV acquisition by about half, compared with zidovudine (AZT) alone.

"Our research demonstrates that even in very high-risk situations where mothers are only identified as being HIV-positive when they give birth or shortly after birth, there is still an effective strategy that can be undertaken to prevent transmission of HIV to the baby," said Karin Nielsen-Saines, MD, Pediatric Infectious Diseases, David Geffen School of Medicine at the University of California Los Angeles (UCLA), Los Angeles, California.

While giving AZT alone to the infant can reduce intrapartum transmission to some degree, our data demonstrates that with the use of 2- or 3-drug regimens to the baby, you can cut transmission to half of what can be achieved with AZT alone."

The study is the first randomised controlled study of post-exposure HIV prophylaxis for babies born in countries where the standard of care is to give the child AZT to prevent infection.

Babies born to HIV-infected mothers who have not received antiretroviral therapy (ART) stand a 25% chance of becoming infected during the mother's pregnancy or at birth. Their chances increase to about 40% when they are breastfed.

The study involved 1,684 formula-fed infants born to HIV-positive mothers in the US, Brazil, Argentina, and South Africa. Within 48 hours of birth, researchers assigned the
newborns to receive AZT alone (n = 566), AZT plus nevirapine (n = 562), or AZT, nelfinavir, and lamivudine (n = 556).

Of the 1,684 infants, 140 were found to be infected with HIV -- 97 were born with the infection and 43 were infected during the birth process.

Among the babies who became infected during the birth process, 24 in the AZT-alone group were found to be infected at age 3 months, compared with 11 in the AZT/nevirapine group and 12 in the AZT/nelfinavir/lamivudine group. This translated into a transmission of 4.8% in the AZT-alone group, 2.2% in the 2-drug group, and 2.4% in the 3-drug group.

The 2-drug therapy was less toxic to the infants than the 3-drug alternative.

Dr. Nielsen-Saines noted that the findings are applicable only to high-risk infants -- those whose mothers didn't receive antiretroviral therapy during pregnancy. Babies born to HIV-positive women who are being effectively treated with antiretrovirals throughout pregnancy already have a less than 1% chance of acquiring HIV from their mothers.

"Our results support combination ART regimens instead of zidovudine alone for prophylaxis in the infants of mothers who have not received antenatal ART," the authors wrote. "Ease of use, reduced toxicity, availability, and low cost suggest that zidovudine plus nevirapine is an attractive option for prophylaxis in infants at high risk for perinatal HIV-1 infection."

SOURCE: University of California, Los Angeles (UCLA), Health Sciences