Lessons for Rectal Microbicide Development From an Acceptability Trial of a Placebo Gel Applied Prior to Receptive Anal Intercourse.

Rectal microbicides, formulated as a gel to be applied before and/or after intercourse, are promising HIV prevention agents and are now in Phase II trials. However, both an optimal formulation and a practical delivery system are needed to ensure that the target population will use the product once efficacy is demonstrated. The precise dynamics of lubricant application by gay and bisexual men who practice anal sex and the qualities they seek in these products are underexplored. As part of a Phase I microbicide acceptability and adherence study conducted in one Puerto Rican and two continental U.S. cities, we recruited 124 young men who have sex with men (YMSM) with a history of unprotected receptive anal intercourse (RAI) and provided them with 40 rectal applicators containing a placebo gel to use prior to RAI during a 12-week period as a proxy for an eventual rectal microbicide. Ninety-five YMSM completed the trial. Their varied preferences as to product viscosity, durability, residue, and mode of application provide important lessons for the design of a product that will be satisfactory to users. Despite many reservations, the participants used the product frequently and found ways to overcome a range of obstacles. A successful rectal microbicide product may need to be presented in a range of viscosities to attract a broad client base.