February 6, 2008
The SWEN studies are three separate but coordinated large-scale Phase III clinical trials funded by the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health. The trials were conducted to determine whether giving HIV-negative infants of HIV-infected mothers a regimen of nevirapine (NVP) for the first 6 weeks of life reduces the risk of HIV transmission through breastfeeding more than the current standard of care: a single dose of NVP given to the mother during labor and to the infant shortly after birth.
The studies were conducted in Ethiopia, India and Uganda and were led by scientists from the host countries and the Johns Hopkins University in the United States, as follows:
In each study, the current standard of care (one dose of NVP to the mother and one to the infant) was offered to all women who were screened and identified as HIV-infected. All of the women were counseled about the risks of HIV transmission associated with breastfeeding. The infants of the mothers who chose to breastfeed and who gave informed consent to participate were selected at random to receive either a single dose of NVP shortly after birth and a daily multivitamin from days 8 to 42 of life; or a single dose of NVP shortly after birth and a daily dose of NVP plus a multivitamin from days 8 to 42.
Only the infants who were HIV-uninfected at birth were included in the analyses of the data from the clinical trials.
The Ugandan study included a third group of mother-infant pairs who received HIV immune globulin in combination with the standard NVP regimen.
All infants in the studies received NVP shortly after birth in keeping with the current standard of care. Because the drug generally remains in infants’ bodies for at least seven days before their systems begin to clear it, researchers began giving the babies the extended daily NVP regimen on their eighth day of life.
In all three studies, the six-week NVP regimen was found to be as safe as and more effective than single-dose NVP in reducing the rates of postnatal HIV transmission and death in breastfeeding infants born to HIV-infected women.
No. The infants who received HIV immune globulin were not included in these analyses. Those data will be analyzed separately and compared with data from the infants who received a single dose of NVP.
The studies began in Ethiopia in February 2001, India in August 2002, and Uganda in July 2004. The researchers completed follow-up of the infants at all three sites by fall 2007.
Initially, 1,964 mother-infant pairs were enrolled in the studies. Sufficient data for evaluation were available for 1,887 mother-infant pairs; 986 of these infants received single-dose NVP, and 901 received the six-week regimen.
Based on the results published in 1999 of a groundbreaking NIAID-sponsored study in Uganda (HIVNET 012), one of the current standards of care used globally to reduce mother-to-child transmission of HIV during labor and delivery in resource-limited settings is a single oral dose of NVP given to an HIV-infected woman in labor and another dose given to the baby shortly after birth. This regimen was found to be more effective, more affordable and easier to administer in resource-limited settings than other regimens. There is no standard regimen for reducing the risk of HIV transmission through breastfeeding.
Because the risk of HIV transmission via breastfeeding is generally believed to be higher during the earliest months of life, the findings from the SWEN studies have the potential to greatly reduce HIV transmission or death in infants while allowing HIV-infected women to breastfeed when it is the only practical option.
In addition, standard practices for preventing mother-to-infant transmission of HIV, which are based on guidelines issued by the World Health Organization and made by individual ministries of health, may be re-evaluated in light of these findings because they suggest that the breastfeeding infants of HIV-infected mothers may benefit from continuing to receive NVP for six weeks.
NIAID has changed the design of an ongoing study of HIV transmission through breastfeeding from HIV-infected mothers to babies who are born without HIV infection. This Phase III clinical trial is evaluating the safety and efficacy of a regimen of NVP given to breastfeeding infants from 6 weeks to 6 months of life. Originally, after receiving the standard single-dose NVP at birth, the infants were randomly selected to receive either a placebo or NVP for their first 6 months of life. The experiment has been modified so all infants receive NVP for the first 6 weeks of life.
Conducting the trial are the HIV Prevention Trials Network, which is funded by NIAID, and the International Maternal Pediatric/Adolescent AIDS Clinical Trials Group, which is co-funded by NIAID and the National Institute of Child Health and Human Development, also part of NIH.
Other studies may take the findings of the SWEN studies into consideration and may be modified as a result.
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Last Updated February 05, 2008