Safety, Acceptability and Preliminary Effectiveness of PC-515 for Vaginal Use as a Possible Microbicide

The primary aims of the study were to assess the safety and acceptability of PC-515 when applied vaginally at least three times weekly for 12 months. Secondary aims were to gather preliminary data on Carraguard's effectiveness in preventing male-to-female transmission of HIV, and other STIs. The hypothesis was that Carraguard would cause little or no significant irritation, including lesions; and that women would find Carraguard acceptable. The study was not powered to determine effectiveness, but based on safety, acceptability and feasibility parameters, the outcome of the Phase 2 trial would enable a decision whether or not to proceed to a Phase 3 trial.

Carraguard™ (PC-515), the Population Council's lead candidate microbicide, was tested in a triple-masked, randomized, placebo-controlled trial fielded in one site in Chiang Rai, northern Thailand. The primary aims of the study were to assess Carraguard's safety (toxicity) - including signs of local irritation, such as itching or burning; changes in vaginal flora; and incidence of abnormal external genital, vaginal, and cervical findings - when applied vaginally for 12 months; to evaluate acceptability; to assess feasibility of conducting a large scale microbicide trial in a non-sex worker population; to gauge women's reactions to a non-contraceptive microbicide; and to explore microbicide use dynamics in a Thai population. Secondary aims were to investigate HIV infections averted (preliminary indications); other sexually transmitted infections averted - including C. trachomatis, N. gonorrhoeae, T. vaginalis, and T. pallidum (preliminary indications); and effect on cervical cytology.