This publication is a follow-up of the Partners PrEP study whose results have been presented showing that daily oral tenofovir disoproxil fumarate or emtricitabine plus tenofovir disoproxil fumarate as PrEP in African heterosexual men and women at high risk of HIV acquisition because they had an HIV infected sexual partner was highly effective (respective efficacy of 67% and 75% versus placebo) (Baeten JM, et al. New England Journal of Medicine, 2012; 367:399-410 ). After this interim review, the placebo group was discontinued and the active groups were continued, and participants initially randomized to placebo were offered rerandomization in 1:1 ratio to TDF or FTC/TDF as PrEP. Of the 4,410 couples followed, 52 incident HIV-1 infections occurred, 31 in individuals assigned to TDF (incidence 0.71 cases per 100 person-years) and 21 in those assigned FTC/TDF (0.48 cases per 100 person-years). HIV-1 prevention efficacy with FTC/TDF was not significantly different from that of TDF alone (hazard ratio 0.67, 95% confidence interval 0.39-1.17; p= 0.16). Detection of tenofovir in plasma samples was associated with an 85% relative risk reduction in HIV-1 acquisition for the TDF group and 93% for the FTC/TDF group. There were no significant differences in the frequency of deaths, serious adverse events, or serum creatinine and phosphorus abnormalities between the two groups.

In conclusion, these results don't rule out the potential for a slight difference in HIV-1 protection with TDF compared with FTC/TDF, but show that once-daily oral TDF or FTC/TDF regimens both provide high protection against HIV-1 acquisition in heterosexual men and women .