A single dose of nevirapine given to an HIV-infected pregnant woman during delivery, and another given to her newborn, can cut the rate of mother-to-child HIV transmission in half. The relative simplicity and affordability of single-dose nevirapine have made it the drug of choice for prevention of mother-to-child transmission in many developing countries.
This new research expands understanding of the risks of drug resistance associated with single-dose nevirapine, but as noted by all three research groups, the clinical implications for patients are not yet clear. More research will be needed to determine whether nevirapine used to prevent mother-to-child transmission affects the chances of successful treatment later with nonnucleoside reverse transcriptase inhibitors, the class of drug to which nevirapine belongs.
Two of the studies analyzed the incidence of nevirapine-associated resistance using laboratory tests more sensitive than standard genotypic assays. In the first, researchers led by Jeffrey A. Johnson, PhD, of the Centers for Disease Control and Prevention, used a new, very sensitive technique to detect resistance mutations in samples of HIV-1 obtained from 50 South African women before and after treatment with single-dose nevirapine. Using a less-sensitive conventional technique called sequence analysis, researchers had previously estimated that viral resistance to nevirapine emerged in approximately 40 percent of women after receiving the single-dose therapy. In contrast, Dr. Johnson and colleagues concluded that resistance emerges in at least 65 percent of women a
Contact: Steve Baragona
Infectious Diseases Society of America