A randomized six-day safety study of an antiretroviral microbicide candidate UC781, a non-nucleoside reverse...

This study evaluated the effect of a single dose and 5 additional consecutive daily doses of UC781 gel at concentrations of 0.1%, 0.25%, 1.0%, and 0% on urogenital irritation.

Forty-eight healthy sexually abstinent women were randomly assigned to 1 of 4 groups.

Urogenital irritation was assessed by pelvic examination, colposcopy, and reports of genital symptoms at baseline and after 1 and 6 doses. Vaginal health was assessed by wet mount and systemic safety by laboratory evaluation after 1 and 6 doses, and UC781 levels were assessed at baseline and after 6 doses.

Some evidence of urogenital irritation was common in all treatment groups and was most often transient and mild. Colposcopic findings were infrequent in the placebo group (8%) and more common in the 3 treatment groups (24%-42%). Edema, which may indicate underlying inflammation, was observed in the vaginal fornix of 2 women exposed to UC781. There was no apparent increase in vaginal infection or clinically significant changes in laboratory values. Two of 12 participants randomized to 1% UC781 gel had detectable plasma levels that were less than the lower level of quantification.

UC781 was well tolerated in this initial dose ranging safety study when used once daily for 6 days in sexually abstinent women. Five safety/pharmacokinetic studies of UC781 are currently underway in women and men, all utilizing UC781 concentrations less than 1%, with twice-daily dosing in some studies, and all involving careful monitoring of exposed epithelium.