To evaluate for changes in sexual behaviors associated with daily pill use among men who have sex with men (MSM) participating in a preexposure prophylaxis trial.
Randomized, double-blind, placebo-controlled trial. Participants were randomized 1:1:1:1 to receive tenofovir disoproxil fumarate or placebo at enrollment or after a 9-month delay and followed for 24 months.
Four hundred HIV-negative MSM reporting anal sex with a man in the past 12 months and meeting other eligibility criteria enrolled in San Francisco, Atlanta, and Boston. Sexual risk was assessed at baseline and quarterly visits using Audio Computer-Assisted Self-Interview. The association of pill taking with sexual behavior was evaluated using logistic and negative-binomial regressions for repeated measures.
Overall indices of behavioral risk declined or remained stable during follow-up. Mean number of partners and proportion reporting unprotected anal sex declined during follow-up (P < 0.05), and mean unprotected anal sex episodes remained stable. During the initial 9 months, changes in risk practices were similar in the group that began pills immediately vs. those in the delayed arm. These indices of risk did not differ significantly after initiation of pill use in the delayed arm or continuation of study medication in the immediate arm. Use of poppers, amphetamines, and sexual performance–enhancing drugs were independently associated with one or more indices of sexual risk.
There was no evidence of risk compensation among HIV-uninfected MSM in this clinical trial. Monitoring for risk compensation should continue now that preexposure prophylaxis has been shown to be efficacious in MSM and other populations and will be provided in open-label trials and other contexts.
*Bridge HIV, San Francisco Department of Public Health, San Francisco, CA;
†Department of Medicine, University of California San Francisco, San Francisco, CA;
‡Division of HIV/AIDS Prevention, Centers for Disease Control and Prevention, Atlanta, GA;
§Fenway Health, Boston, MA;
‖AIDS Research Consortium of Atlanta, Atlanta, GA;
¶Northrop Grumman Corporation, Falls Church, VA;
#Department of Epidemiology and Biostatistics, University of California San Francisco, San Francisco, CA;
**Beth Israel Deaconess Hospital and Harvard Medical School, Boston, MA;
††HIV Prevention Section, San Francisco Department of Public Health, San Francisco, CA; and
‡‡Quantitative Sciences and Data Management branch, Division of HIV/AIDS Prevention, Centers for Disease Control and Prevention, Atlanta, GA.
Correspondence to: Albert Y. Liu, MD, MPH, 25 Van Ness Avenue, Suite 100, San Francisco, CA 94102-6033 (e-mail: firstname.lastname@example.org).
Supported by funds from the US Department of Health and Human Services, Centers for Disease Control and Prevention, Contracts #200-2003-03003, #200-2003-03007, and #200-2004-09853. Study drug was supplied by Gilead Sciences.
The findings and conclusions in this report are those of the authors and do not necessarily represent the official position of the Centers for Disease Control and Prevention. In addition, the views expressed herein do not necessarily reflect the official policies of the City and County of San Francisco; nor does mention of the San Francisco Department of Public Health imply its endorsement.
Presented in part as a poster presentation at the 6th International AIDS Society Conference on HIV Pathogenesis, Treatment, and Prevention, 17-20 July, 2011, Rome Italy.
A.Y.L. and S.P.B. have received honoraria from Clinical Care Options. The institution of K.M. has received unrestricted research grants from Gilead Sciences, the pharmaceutical company that manufactures tenofovir, and other pharmaceutical companies. The institution of M.T. institution has received research grant funding from Gilead Sciences and other pharmaceutical companies and has had a prevention research consultancy with Gilead Sciences. The remaining authors have no conflicts of interest to disclose.
Received November 16, 2012
Accepted February 21, 2013