HPTN Bibliographic Record

Tabet SR, Surawicz C, Horton S, Paradise M, Coletti AS, Gross M, Fleming TR, Buchbinder S, Haggitt RC, Levine H, Kelly CW, Celum CL. Safety and toxicity of nonoxynol-9 gel as a rectal microbicide. Sex Transm Dis. 1999, 26: 564-71.
BACKGROUND AND OBJECTIVES: Methods of HIV and STD prevention, which can be controlled by the receptive partner, are a high priority for research and development. Studies on the safety of Nonoxynol-9 (N-9) on the vaginal mucosa have yielded conflicting results. No Phase I study has evaluated the effect of N-9 on the rectal mucosa. GOALS: To assess the safety of 52.5 mg of N-9 in a 1.5-g gel when applied one to four applicators per day to the rectum and penis. STUDY DESIGN: The study included 25 HIV-negative and 10 HIV-positive, monogamous gay male couples in which each partner was exclusively insertive or receptive while using N-9 gel. Each participant served as his own control during placebo gel use compared to during N-9 gel use. Receptive partners underwent anoscopic examination after 1 week of placebo use and after 2, 5, and 6 weeks of N-9 gel use, with rectal biopsies obtained after 1 week of placebo use and after 5 and 6 weeks of N-9 gel use. Insertive partners had safety monitoring after 1 week of placebo use and after 2, 5, and 6 weeks of N-9. RESULTS: No rectal ulcers were detected; superficial rectal erosions were noted in two HIV-negative participants. Abnormal or slightly abnormal histologic abnormalities of rectal biopsies were detected in 31 (89%) receptive participants after N-9 gel use compared to 24 (69%) participants after 1 week of placebo gel use. Meatal ulceration, not caused by herpes simplex virus, was detected in one HIV-negative participant. CONCLUSION: Low-dose N-9 gel was not associated with macroscopic rectal and penile epithelial disruption or inflammation, but histologic abnormalities were commonly observed during N-9 gel as well as during placebo gel use.