BACKGROUND:

Maraviroc (MVC) is a candidate for HIV pre-exposure prophylaxis (PrEP).

METHODS:

Phase 2 48-week safety/tolerability study of four regimens: MVC alone, MVC+emtricitabine (FTC), MVC+tenofovir disoproxil fumarate (TDF), and TDF+FTC. Eligible participants were HIV-uninfected men and transgender women reporting condomless anal intercourse with >1 HIV-infected or unknown-serostatus man within 90 days. At each visit, assessments, laboratory testing, and counseling were done. Analyses were intention-to-treat. Registry #NCT01505114 RESULTS:  Among 406 participants, 84% completed follow-up, 7% stopped early, and 9% were lost-to-follow-up; 9% discontinued their regimen early. The number discontinuing and time-to-discontinuation did not differ among study regimens (p=0.60). Grade 3-4 adverse event rates did not differ among regimens (p=0.37). In a randomly-selected subset, 77% demonstrated detectable drug concentrations at week 48. Five participants acquired HIV infection (4 MVC alone, 1 MVC+TDF; overall annualized incidence 1.4% [95% CI:0.5%, 3.3%], without differences by regimen, p=0.32); 2 had undetectable drug concentrations at every visit, 2 had low concentrations at the seroconversion visit, and 1 had variable concentrations.

CONCLUSIONS:

MVC-containing regimens were safe and well-tolerated compared to TDF+FTC; this study was not powered for efficacy. Among those acquiring HIV infection, drug concentrations were absent, low, or variable. MVC-containing regimens may warrant further study for PrEP.

J Infect Dis. 2016 Nov 2. pii: jiw525. [Epub ahead of print]
PMID: 27811319