Recommendations for the development of vaginal microbicides. International Working Group on Vaginal Microbicides.

Vaginal microbicides are products for vaginal administration that can be used to prevent HIV infection and other sexually transmitted diseases (STD). We recognize two potential sources of vaginal microbicides: existing spermicides and new products (new products may or may not be spermicidal). This document is meant to serve as a general guide for development and evaluation of existing and new products. For new products preclinical studies will be required. Depending upon indication, in vitro activity against HIV, target STD, and sperm should also be assessed. Compatibility with barrier method materials should also be evaluated. The physical-chemical properties of the active agent and the clinical formulation should be assessed. Animals studies should be conducted to assess its safety and predict dosing; use of various models to assess local toxicity is indicated and microbicidal activity of the product may be evaluated if appropriate models are available. Carcinogenicity testing and segment III reproduction studies (perinatal and post-natal studies in rats) may be performed concurrently with Phase III clinical trials. All vaginal microbicides, including existing spermicides and new products, should be clinically evaluated for safety and efficacy. Safety studies are necessary because irritation of vaginal and cervical mucosae has been recently associated with spermicide use and those lesions might increase HIV transmission. Efficacy studies to assess prevention of HIV infection and/or STD, depending upon the product indication, should then be conducted with products that have been evaluated for safety and appear to be non-toxic to tissue. For spermicidal microbicides contraceptive efficacy studies will be needed.