HIV prevention, treatment highlighted at Conference on Retroviruses and Opportunistic Infections

Preventing mother-to-child transmission, HIV transmission factors among key topics presented

Today was the last day of the 18th Conference on Retroviruses and Opportunistic Infections, a key HIV/AIDS research meeting being held at the Hynes Convention Center in Boston from February 27 through March 2. Highlighted below are selected presentations from March 2nd on research supported by the National Institute of Allergy and Infectious Diseases (NIAID) and the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), both components of the National Institutes of Health.

Karin Nielsen-Saines, M.D., of the David Geffen School of Medicine at the University of California, Los Angeles, presented findings from an international study known as NICHD HPTN 040/PACTG 1043, which was conducted by NICHD researchers and their colleagues. This Phase III trial compared the safety and efficacy of three antiretroviral drug regimens given to infants as post-exposure prophylaxis to prevent HIV acquisition from their infected mothers during birth. The study found that in formula-fed infants born to HIV-infected women who did not receive antiretroviral drugs before labor, post-exposure prophylaxis with a two- or three-antiretroviral-drug regimen is more effective than 6 weeks of zidovudine alone for preventing HIV transmission during birth. The study also found that a regimen of 6 weeks of zidovudine plus three doses of nevirapine, with its lower toxicity and greater ease of use, may be preferable to a regimen of 6 weeks of zidovudine plus 2 weeks of lamivudine and nelfinavir.

Paul Palumbo, M.D., of the Dartmouth-Hitchcock Medical Center in Lebanon, N.H., presented findings from IMPAACT P1060. This clinical trial, conducted in HIV-infected infants in resource-limited settings, compared antiretroviral therapy (ART) based on nevirapine to ART based on ritonavir-boosted lopinavir. The latter therapy outperformed nevirapine-based ART in HIV-infected children under age 3 who had not received single-dose nevirapine at birth to prevent mother-to-child HIV transmission. Previously, this study showed that ritonavir-boosted lopinavir-based ART also worked better than nevirapine-based ART in HIV-infected children who had received single-dose of nevirapine at birth. Taken together, these findings have important implications for the treatment of HIV-infected children in resource-limited settings.

Andrew Redd, Ph.D., of NIAID in Bethesda, Md., reported that the strain of HIV that a person acquires through sex tends to be very similar to the strain he or she transmits sexually to others, even though the rapidly mutating virus diversifies over time into a wide variety of strains within an infected individual. According to Dr. Redd, it is likely that these acquired and transmitted strains share characteristics that increase their transmissibility. This suggests that future HIV vaccine strategies should focus on identifying and targeting these preferentially transmitted HIV strains.