Notice on Efavirenz and Pregnancy
DuPont Merck has informed researchers, physicians, and patients using the experimental drug efavirenz (Sustiva (tm), also known as DMP-266) that malformations were found in three of 13 monkey fetuses after their mothers were given the drug throughout their pregnancy, at doses which approximate human blood levels of the drug. All the malformations are believed to have occurred very early in pregnancy.The trials of efavirenz have always required volunteers to use effective contraception, and have required pregnancy tests for women at each study visit; this was done as a general precaution because the drug is experimental. The new information emphasizes the importance of not becoming pregnant while taking efavirenz.
Earlier studies in rats and rabbits had not found any such problems. According to DuPont Merck, this is the first time a pharmaceutical company has tested an antiretroviral in monkeys for safety during pregnancy.
Because there is no indication of harm in late pregnancy, the drug has not been ruled out for use in preventing maternal/infant transmission of HIV.
More than 4,000 patients have received efavirenz in trials so far, and these trials are continuing as planned.
