DURBAN, South Africa- A team of scientists from the United States and Uganda reported today that the inexpensive AIDS drug nevirapine, when given to both mother and child around the time of birth, greatly reduces mother-to-infant transmission of HIV up to a year after the medicine was given. The updated results of the study were presented today in a session of late-breaking research results at the 13th International AIDS Conference in Durban, South Africa.
The latest findings stem from the continued follow-up of breastfeeding mothers and their babies enrolled in a clinical trial (HIVNET 012). The trial was supported by the National Institute of Allergy and Infectious Diseases (NIAID), part of the U.S. National Institutes of Health. Last year, results from that trial (http://www.niaid.nih.gov/cgi-shl/simple/release.cfm) showed that a short regimen of nevirapine given to both mother and child significantly reduced HIV transmission. Today's announcement reported that this reduction in mother-to-infant transmission of HIV was sustained even though the infants were breastfed.
Conducted at the teaching hospital of Makerere University in Kampala, Uganda, the study compared the safety and efficacy of a short course of nevirapine with that of another AIDS drug, AZT. One group of women received a single dose of nevirapine during labor and their infants received one dose within 72 hours of birth. The second group of women received AZT during labor while their newborns received twice daily doses for 7 days. After 6-8 weeks, both regimens were well tolerated, but mothers and infants who received nevirapine had a 42 percent lower risk of HIV transmission when compared with those receiving AZT.
New data on those same infants 12 months later show nevirapine continues to reduce risk of HIV transmission over AZT. After 6-8 weeks, nevirapine showed a 42 percent reduction in HIV transmission compared to AZT. At 12 months, the reduction was 39 percent, and preliminary results indicate a reduction of 42 percent after 18 months. In addition, the benefits of nevirapine occurred despite breastfeeding by the women in the study.
Genetic analysis of HIV in the mothers showed that while a small number of mutations do occur in the virus that make it impervious to the drug, those mutations fade from detection within 13-18 months after delivery. This suggests that repeat doses of nevirapine given to the mother will continue to prevent HIV transmission during future pregnancies.
Researchers also assessed how well the amount of HIV and CD4 T-cells in the mother's blood would predict the likelihood of her passing the virus on to her baby. Women with more virus and fewer CD4 T-cells in their blood were more likely to transmit HIV to their offspring than were those with less virus and more CD4 cells.
Together, these findings further indicate that a short nevirapine regimen is an effective, simple, and extremely low cost method for preventing transmission of HIV from mother to child in developing countries.
The trial was led by Dr. Brooks Jackson at The Johns Hopkins University and Professor Francis Mmiro at Makerere University. Statistical analysis was coordinated by Dr. Tom Fleming at the Fred Hutchinson Cancer Research Center in Seattle.
NIAID is a component of the National Institutes of Health (NIH). NIAID conducts and supports research to prevent, diagnose, and treat illness such as HIV disease and other sexually transmitted diseases, tuberculosis, malaria, asthma and allergies. NIH is an agency of the U.S. Department of Health and Human Services.
Press releases, fact sheets and other NIAID-related materials are available on the NIAID Web site at http://www.niaid.nih.gov
The National Institute of Allergy and Infectious Diseases is a component of the National Institutes of Health, U.S. Department of Health and Human Services.