Phase 1 trial of nonoxynol-9 film among sex workers in South Africa

Abstract

To assess the acceptability and safety of a vaginal nonoxynol-9 film in a group of sex workers at a truck stop in South Africa. A randomized double-blinded crossover trial was conducted between April 1995 and July 1995. Seventy-twomg nonoxynol-9 film and an identical glycerine placebo film. Following informed consent, each study participant was randomly assigned the designated pre-coded film for 1 month. The second month was a film-free washout period and the participants used the alternate film in the third month. Besides measuring behavioural and clinical outcomes, colposcopy examination for genital lesions, serology and microbiology investigations for sexually transmitted diseases and semi-quantitative PCR for vaginal HIV load estimates were performed. Twenty women participated in the study. The women reported, on average, 19 sexual encounters per week. Vaginal intercourse was protected 25% of the time by condoms. On average, 11 vaginal films, either nonoxynol-9 or placebos were inserted per week. There were no statistically significant differences between the two treatment groups for genital lesions (P=0.29), reported side effects (P=0.73), and viral load (P=0.9). However, the proportions of clinically detected genital lesions (six out of eight versus two out of eight) and self-reported side-effects (five out of eight versus three out of eight) were higher in the nonoxynol-9 group when compared with the placebo group. Incident sexually transmitted diseases occurred more frequently in the placebo group. An increased viral load was associated with the development of a genital lesion (relative risk, 6.0; 95% confidence interval, 0.81-44.4). The 72mg film formulation of nonoxynol-9 was an acceptable product for use in this population of sex workers. Although no statistically significant differences in adverse outcomes were detected, clinically there appeared to be an increase in minor lesions and self-reported side-effects with nonoxynol-9 and less protection against sexually transmitted diseases with the placebo. Furthermore, HIV shedding was correlated with the presence of incident vaginal or cervical lesions. This brings into question the potential narrow margin of safety for this product; additional Phase 2 studies are therefore required.