Safety and adherence to intermittent emtricitabine/tenofovir for HIV pre-exposure prophylaxis (PrEP) in Kenya and Uganda
G. Mutua1, E.J. Sanders2, A. Kamali3, F. Kibengo3, P. Mugo2, O. Anzala1, H. Grosskurth3, J. Haberer4, D. Bangsberg4, B. Barin5, D. Vooijs6, C. Verlinde6, J. Rooney7, P. Fast6, S. Berkley6, F. Priddy6
1Kenya AIDS Vaccine Initiative, University of Nairobi, Nairobi, Kenya, 2Kenya Medical Research Institute, Ctr for Geographic Medicine Research, Coast, Kilifi, Kenya, 3MRC Entebbe, Entebbe, Uganda, 4Harvard Medical School/ Harvard Initiative for Global Health-HIGH, Boston, United States, 5EMMES, Rockville, United States, 6International AIDS Vaccine Initiative, Medical Affairs, New York, United States, 7Gilead Sciences, Foster City, United States
Background: Little is known about safety and adherence to intermittent PrEP regimens, which may be more feasible than daily dosing in some settings. We present preliminary data on the safety and adherence to daily and intermittent FTC/TDF among Kenyan MSM/FSW and Ugandan HIV discordant couples (DC).
Methods: MSM, FSW (Kenya) and HIV-uninfected partners in DC (Uganda) were randomized to daily FTC/TDF or placebo, or intermittent (Monday, Friday and within 2 hours after sex, not to exceed one dose per day) FTC/TDF or placebo in a 2:1:2:1 ratio and are being followed monthly with standardized adherence and risk reduction counseling, HIV testing, and safety evaluation for 4 months. Adherence is assessed with medication event monitoring system (MEMS). Sexual activity data are collected via daily text message (SMS) queries.
Results: 67 MSM, 5 FSW and 32 DC (24M:8F) have been enrolled to date. Data for 37% of follow-up time are reported, blinded to drug/placebo assignment. All adverse events (AEs) were mild or moderate with most judged unlikely related or not related to study drug/placebo. Both dose regimens had similar rates of AEs. No significant renal dysfunction was found. No drug-related SAEs were reported. Median [inter-quartile range] unadjusted MEMS adherence to daily dosing was 84% [75-96] in MSM/FSW and 101% [96-104] in DCs. Unadjusted MEMS adherence to fixed intermittent doses was 66% [50-88] in MSM/FSW and 91% [84-116] in DCs, while adherence to any post-coital doses was 25% [10-60] in MSM/FSW, and 50% [33-77] in DC. Self-reported adherence to post-coital doses within 2 hours of sex was higher than MEMS adherence. [Complete safety and adherence data will be available July 2010]
Conclusions: These preliminary, blinded data suggest that intermittent and daily FTC/TDF have similarly acceptable safety profiles. Adherence to fixed intermittent doses was comparable to daily dosing, however post-coital dosing may be challenging in these settings.
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