What's up with nonoxynol-9?

Advantage-S, a spermicide containing nonoxynol-9 (N-9), has recently been shown in a randomised, controlled trial sponsored by UNAIDS not to offer women protection against sexual transmission of HIV. The women in the trial, all sex workers, reported having an average of 3.6 partners per day and about 70 coital acts per month during the study period. At the end of the trial, the Advantage-S group was found to have a higher incidence of new HIV infections than the control group, who were using a vaginal lubricant. Two other recent studies have found that low dose N-9 products do not provide protection against bacterial STDs such as gonorrhoea and chlamydia--a finding that contradicts earlier wisdom based on less rigorous studies. Contrary to certain media headlines, however, the results of these trials do not suggest that effective microbicides cannot be developed, only that Advantage-S, which was developed as a spermicide and not as a microbicide, is probably not one of them. The failure of Advantage-S to show protection in the UNAIDS-sponsored trial underscores the urgent need to accelerate research to develop a safe and effective topical microbicide.