Extended Nevirapine Regimens Reduce HIV Transmission
An extended course of the antiretroviral drug nevirapine (NVP) helps the breastfeeding babies of HIV-infected mothers remain HIV-negative and live longer, according to several new studies presented at the 15th Conference on Retroviruses and Opportunistic Infections held in Boston from February 3-6.
Three coordinated, large-scale Phase III clinical trials sponsored by the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health (NIH), found that NVP given once daily to breastfeeding infants from days 8 to 42 of life cut the rate of HIV transmission via breastfeeding by almost half at 6 weeks when compared with a single dose of NVP given to infants at birth, the current standard of care. Moreover, at 6 months, the risk of postnatal HIV infection or death for babies who received NVP for six weeks was nearly one-third less than the risk for infants given only a single dose. These clinical trials are known as the Six-Week Extended NVP (SWEN) studies.
A separate study--the PEPI-Malawi study--sponsored by NIH's National Institute of Child Health and Human Development (NICHD) and the U.S. Centers for Disease Control and Prevention (CDC) found that giving NVP daily to breastfeeding infants from 7 days to 14 weeks of age cut the rate of HIV transmission by half for up to nine months.
According to the authors of the studies, these findings are critical because approximately 150,000 infants worldwide acquire HIV annually through breastfeeding, and the risk of HIV transmission is generally believed to be greatest during the earliest months of life. Despite that risk, the World Health Organization and UNICEF recommend that infants born to HIV-infected mothers who lack access to safe, affordable and sustainable replacement feeding should breastfeed for at least six months, because under such conditions, breastfeeding may protect infants from other causes of illness and death that pose a greater risk than HIV infection itself. Replacement feeding, early weaning or both are not options for many women and their babies for economic, cultural, and health and safety reasons.
The SWEN Studies
The NIAID-sponsored SWEN studies sought to determine whether giving an extended daily regimen of NVP to the breastfeeding babies of HIV-infected mothers would reduce the rates of HIV acquisition and death in these infants more than the standard of care alone.
Investigators from the Johns Hopkins University (JHU) and an international team of researchers enrolled nearly 2,000 mother-infant pairs in three separate but coordinated studies that began in Ethiopia in 2001, India in 2002 and Uganda in 2004. The available standard of care in these countries for preventing mother-to-child transmission during labor and delivery is a single dose of NVP to the HIV-infected mother during labor and a single dose to her baby shortly after birth. This care was offered to all the women who were screened and identified as HIV-infected. Also, all women were counseled about the potential risks of HIV transmission associated with breastfeeding.
The infants of mothers who chose to breastfeed their babies and who gave informed consent were then selected at random to receive either one of two regimens: a single dose of NVP shortly after birth and a daily multivitamin from days 8 to 42; or a single dose of NVP shortly after birth and a daily dose of NVP plus a multivitamin from days 8 to 42. (The extended treatment period was begun at day 8 because previous studies have indicated that giving infants a single dose of NVP shortly after birth protects them for several days from transmission of HIV via breastfeeding.) Data were analyzed to determine the impact of extended NVP therapy on HIV transmission and rates of infant death at 6 weeks and 6 months.
The combined rates of HIV infection and death at both 6 weeks and 6 months were significantly lower in the SWEN group than in the group that received the standard, single-dose NVP regimen alone. The risk of postnatal HIV infection or death at 6 weeks was 3.7 percent in the SWEN group, 42 percent lower than in the single-dose group. At 6 months, the risk was 8.0 percent in the SWEN group, 27 percent lower than in the single-dose group.