Phase III microbicide trial methodology: opinions of experienced expanded safety trial participants in South Africa.

In preparation for effectiveness trials of candidate vaginal microbicides, scientists are debating trial design and implementation challenges, including choice of control arm(s), product-sharing across arms, and visit schedules. This study involved a survey of South African women participating in an expanded safety trial of the candidate microbicide Carraguard gel. The first 100 consenting women who attended the study clinics in Ga-Rankuwa and Gugulethu (total N = 200) were interviewed; all women had been using a study gel for at least 6 months at the time of the interview. The study found that many participants thought that including a condoms-only arm would result in increased product-sharing, male partner resistance to trial participation and decreased enrollment; no clear patterns emerged regarding the potential effect on condom use and cohort retention. The majority of women preferred a monthly visit schedule, would be willing to use a product for 2 years, and thought that their product use would not decrease over time. Thus flexibility in trial design and implementation strategies is needed until evidence-based decisions can be made. When including a condoms-only arm, extra efforts should be made to explain the importance of all study arms to potential participants and to measure adherence and product-sharing.