Biomarkers for evaluating vaginal microbicides and contraceptives: discovery and early validation.

A biomarker has been defined as "a characteristic that is objectively measured and evaluated as an indicator of normal biological processes, pathogenic processes, pharmacological responses to a therapeutic intervention." Biomarkers can reduce the costs and time required to get a drug from discovery to market. Topical microbicides are new drugs designed to prevent HIV and other sexually transmitted infections (STIs). Biomarkers that may be important in microbicide development include biomarkers of semen exposure, biomarkers of cervicovaginal inflammation, and biomarkers of HIV and STIs. The development of biomarkers for use in microbicide development is a high priority. This supplement reports on a meeting entitled "Biomarkers for Evaluating Vaginal Microbicides and Contraceptives: Discovery and Early Validation," held in Reston, VA on November 16 to 17, 2006. It was sponsored by CONRAD and the Alliance for Microbicide Development with funding from the Bill and Melinda Gates Foundation and the United States Agency for International Development (USAID). The meeting was convened to look at the ways in which biomarkers could be used to attenuate the challenges alluded to above. Availability of key biomarkers could expedite the development of microbicides, for which there is a pressing need, especially in developing countries where combinations of cultural and socioeconomic pressures on women constrain their ability to protect themselves from STIs. Although the meeting was held 2 years ago, the material reviewed and conclusions drawn are still relevant.