Challenges in Microbicide Trial Design and Implementation

Microbicide development began more than fifteen years ago when optimism about the swift development of an HIV vaccine began to wane and researchers recognized that significant progress in HIV transmission prevention could not be expected with the currently available HIV prevention tools. Sexual abstinence and limiting the number of sexual partners may not be feasible for those women who because of their constrained educational and employment opportunities are financially dependent on men. After two decades of male condom promotion the absolute number of male condoms used worldwide has increased dramatically but consistent condom use in primary partnerships remains rare. Women are often unable to convince their male partners to use a condom or to remain with one partner because of social cultural and economic gender inequalities. Microbicides are being developed as products to apply topically inside the vagina or rectum to prevent infection with HIV and potentially with other sexually transmitted infections (STIs). They could be formulated as gels creams suppositories or vaginal rings; they could be contraceptive or not; and they could be used alone or in combination with a physical barrier. For many women and couples the importance of having children is a major obstacle to condom use and noncontraceptive microbicides would offer them a means of protecting themselves from HIV while trying to conceive. By reducing the risk of HIV infection among women microbicides could contribute to a reduction in mother-to-child transmission. They could prevent transmission from women to their male partners and reinfection among women who are HIV-positive. Researchers are also investigating ways that microbicides can be formulated for use in the rectum during anal sex. (excerpt)