A Pilot Study of Pre-Exposure Prophylaxis (PrEP) to Evaluate Safety, Acceptability, and Adherence in At-Risk Populations in Kenya, Africa

Summary

This study will evaluate the safety and acceptability of an intermittent and daily PrEP regimen using Tenofovir Disoproxil Fumarate plus Emtricitabine (FTC/TDF) in men and women at risk for HIV, and it will directly compare adherence and intracellular drug levels in daily and intermittent PrEP recipients. It will also evaluate the relationship between drug adherence, sexual behavior and intracellular drug levels with an intermittent PrEP regimen. In addition it will evaluate the relationship between adherence to an intermittent PrEP regimen and timing of sexual activity in relation to PrEP dosing. The study will use objective medication event monitoring medication event monitors (MEMS) adherence measurement and evaluate the feasibility of newer adherence measurements such as hair sampling and plasma drug levels. The study will also evaluate the feasibility of using SMS (text messages) to collect sexual activity data in an African setting. It will allow study teams and communities to prepare for potential subsequent larger trials of intermittent PrEP. This study is not sized to evaluate efficacy. If the intermittent PrEP regimen is shown to be safe, feasible in terms of adherence, and achieves intracellular drug levels similar to daily PrEP, these data could be used to design a larger phase 2 study with one or more intermittent PrEP regimens. The goal of such a trial would be to provide bridging data if daily PrEP regimens are found to be effective or to prepare for efficacy or non-inferiority trials of intermittent versus daily PrEP. Investigation of immune responses associated with FTC/TDF will also be evaluated in the pilot study. The proportion of volunteers on FTC/TDF with HIV-specific immune responses, due to exposures that did not lead to established HIV infection, will be assessed at 2-3 time points and compared to responses in volunteers assigned to placebo. Immune responses may be correlated with risk behavior and host factors, such as human leukocyte antigen (HLA) type. As noted above, very few HIV infections are expected to occur during the study, so correlation of HIV-specific immune responses and protection from infection or attenuation of disease progression will not be possible until a larger study is conducted.

Timeline

Start

2009-10

Primary completion

2010-06

Completion

2010-07

Publications

• Baxi SM, Liu A, Bacchetti P, Mutua G, Sanders EJ, Kibengo FM, Haberer JE, Rooney J, Hendrix CW, Anderson PL, Huang Y, Priddy F, Gandhi M. Comparing the novel method of assessing PrEP adherence/exposure using hair samples to other pharmacologic and traditional measures. J Acquir Immune Defic Syndr. 2015 Jan 1;68(1):13-20. doi: 10.1097/QAI.0000000000000386.
• Mutua G, Sanders E, Mugo P, Anzala O, Haberer JE, Bangsberg D, Barin B, Rooney JF, Mark D, Chetty P, Fast P, Priddy FH. Safety and adherence to intermittent pre-exposure prophylaxis (PrEP) for HIV-1 in African men who have sex with men and female sex workers. PLoS One. 2012;7(4):e33103. doi: 10.1371/journal.pone.0033103. Epub 2012 Apr 12.

Drugs

Indications