Men who have sex with men (MSM), and transgender women (TGW) are disproportionately affected by HIV. Safe and acceptable HIV prevention methods that target the site of initial rectal mucosal infection are needed.
MTN-017 was a Phase 2, three-period, randomized sequence, open-label, expanded safety and acceptability crossover study comparing rectally applied reduced-glycerin (RG) 1% tenofovir (TFV) and oral emtricitabine/TFV disoproxil fumarate (FTC/TDF). We enrolled healthy HIV-1 uninfected MSM and TGW >18 years at 8 sites. In each 8 week study period participants were randomized to RG-TFV rectal gel daily; or RG-TFV rectal gel before and after receptive anal intercourse (RAI) (or at least twice weekly in the event of no RAI); or took daily oral FTC/TDF. Participants were seen every 4 weeks. High product adherence was defined as >80% of expected doses taken, assessed by convergence scoring of daily texts and study product returns. Additionally, qualitative plasma TFV testing was done with results provided to participants at their next clinic visit. Generalized estimating equation models with exchangeable correlation structures and robust errors were used to compare safety, acceptability, and adherence between the three regimens.
Participants (n=187) were recruited from the United States (4 sites, 42%), Thailand (2 sites, 29%), Peru (1 site, 19%), and South Africa (1 site, 10%) with mean age of 31.1 years (range 18-64). Twelve percent were TGW/women by self-report and 80% had a college education. There were no differences in Grade 2 or higher adverse event rates in participants using daily gel (Incidence Rate Ratio (IRR): 1.03, p=0.88) or RAI gel (IRR: 0.88, p=0.43) compared to FTC/TDF. High adherence was less likely during the daily gel regimen (Odds Ratio (OR): 0.35, p<0.001) and participants reported they would be less likely to use the daily gel regimen for HIV protection compared to FTC/TDF (OR: 0.38, p<0.001). Adherence to gel use at least twice weekly (RAI regimen) was similar to FTC/TDF (p=0.7) with no difference in intention to use product for HIV prevention (p=0.2).
Rectal application of RG TFV gel was safe in MSM and TGW. Similar adherence and intention to use product for HIV prevention was seen with gel applied at least twice weekly and FTC/TDF. Future topical rectal product development should focus on convenient dosing regimens.