Six-Month Delay in Onset of Nevirapine-Based Antiretroviral Therapy Can Prevent Drug Resistance Following Single-Dose Nevirapine During Labor, Study Says
Delaying the start of a nevirapine-based antiretroviral therapy by six months can prevent the development of drug resistance in HIV-positive women who took single-dose nevirapine during labor to prevent mother-to-child transmission of the virus, according to a study published on Thursday in the New England Journal of Medicine, the New York Times reports (McNeil, New York Times, 1/11). For the study, Harvard University researchers beginning in 2001 followed 218 HIV-positive women in Botswana who had taken single-dose nevirapine during labor along with a short treatment of antiretrovirals during pregnancy. Sixty women began nevirapine-based antiretroviral therapy within six months of giving birth, and 158 began the treatment six months after delivery. The researchers found that in the group of women who started the treatment within six months of delivery, 41% experienced treatment failure. Of the women who waited six months, 12% experienced treatment failure (Donnelly, Boston Globe, 1/11). According to the study, HIV-positive women who wait at least six months after delivery to start an antiretroviral treatment regimen that includes nevirapine are 70% more likely to benefit from treatment than women who begin treatment earlier (McAlary, VOA News, 1/10). Shahin Lockman, the study's lead author and an assistant professor at the Harvard School of Public Health, said the women who waited six months to begin treatment likely had better results because the amount of HIV that is resistant to nevirapine decreases over time.
According to the Globe, HIV prevention efforts in recent years have been "set back" by findings that pregnant women who received single-dose nevirapine during delivery developed resistance to the drug (Boston Globe, 1/11). A study published in April 2006 in the journal Proceedings of the National Academy of Sciences found that more than one-fifth of HIV-positive pregnant women who took single-dose nevirapine to prevent mother-to-child HIV transmission have some resistance to the drug one year after treatment (Kaiser Daily HIV/AIDS Report, 5/3/06). An estimated 10% of HIV-positive pregnant women in sub-Saharan Africa have access to interventions aimed at preventing MTC HIV transmission. In cases in which antiretrovirals are available, single-dose nevirapine at birth often is the only option, according to the Globe. Some researchers estimate that more than 875,000 women and children in developing countries have received single-dose nevirapine at birth (Boson Globe, 1/11). The study's findings, therefore, have "implications for poor women" worldwide, the Times reports. "This is a real glimmer of hope," Catherine Hankins, chief scientific adviser for UNAIDS, said, adding, "There was real concern that single-dose nevirapine was blowing the use of that whole class of drugs" (New York Times, 1/11). The study's findings also should "give greater confidence" to many African countries to promote the use of nevirapine during delivery to prevent MTC HIV transmission, the Globe reports. Max Essex, chair of HSPH AIDS Initiative and a study author, urged health care workers to exercise good judgment when treating HIV-positive women who have just given birth (Boston Globe, 1/11). "If you can wait six months to administer nevirapine-based ART, do so," Essex said, adding, "If not, treat only with combinations of drugs that do not contain nevirapine or nevirapine-related drugs. Implementing this policy can improve the health of women who need AIDS treatment" (Emery, Reuters, 1/10). According to Lynne Mofenson -- chief of research on child, adolescent and maternal AIDS at NIH's National Institute of Child Health and Human Development -- the study's findings are in line with a World Health Organization guideline that limits single-dose nevirapine to pregnant HIV-positive women who are able to wait six months after birth for nevirapine-based treatment (VOA News, 1/10).
NPR's "All Things Considered" on Wednesday reported on the study. The segment includes comments from Lockman and James McIntyre, director of Perinatal Research Unit at Baragwanath Hospital in South Africa (Wilson, "All Things Considered," 1/10). Audio of the segment is available online.
The study is available online.