Safety of multiple daily applications of COL-1492, a nonoxynol-9 vaginal gel, among female sex workers. COL-1492 Phase II Study Group.

Rationale: COL-1492 is a nonoxynol-9 (N-9)-containing vaginal gel and may be a potential microbicide. As part of an effectiveness trial, an initial toxicity study was conducted.

Objectives: The main objective of the reported study was the assessment of the toxicity of a 52.5 mg N-9 gel, COL-1492, when used a number of times each day by female sex workers.

Methods: This was a randomized, placebo-controlled triple-blinded trial among female sex workers. The participants were asked to use the product for each vaginal sexual act. At each monthly visit a gynaecological examination with sexually transmitted disease sampling and colposcopy was performed. Venous blood was drawn for syphilis and HIV serology. All women received intensive counselling on condom use. Male condoms and sexually transmitted disease treatment were given free of charge.

Results: Only blinded results on the colposcopic examinations are reported. The incidence of lesions with or without an epithelial disruption was low: 0.06 and 0.29, respectively, per 100 woman-days in group A; 0.09 and 0.26 respectively per 100 woman-days in group B. There was no significant difference between the two arms.

Conclusion: The multiple daily use of COL-1492 by female sex workers did not show an increase of local toxicity over that of a placebo. Colposcopy was discontinued in the autumn of 1997 in accordance with a Data Safety Monitoring Board decision. In the currently ongoing effectiveness trial the assessment of the product's toxicity continues to be monitored by simple visual examination.