Background: In ANRS IPERGAY, on demand PrEP with TDF-FTC reduced by 86% the incidence of HIV-1 infection in high risk MSM (Table). However, the cumulative follow-up time on TDF-FTC was limited and the long term efficacy and safety of this strategy remains to be assessed.
Methods: From November 2014 to June 2016, participants who were followed or being screened in the ANRS IPERGAY trial were offered to continue follow-up every two months with open-label TDF-FTC. The primary study objectives of this open-label phase were to assess study retention, HIV incidence, safety and changes in sexual behaviour.
Results: Among the 400 pts initially enrolled in the study, 336 (84%) were eligible for the open-label phase, and all but 3 (99%) signed a new informed consent form. Twenty-nine additional pts were also enrolled. Overall, 362 pts were enrolled for a cumulative follow-up time of 334 person-years (py), until December 14, 2015 with a median follow-up of 11.7 months. Study retention was good with only 23 pts discontinuing follow-up (6.4%). Only a single individual who had discontinued PrEP acquired HIV-1 infection and the overall incidence of HIV-1 infection was 0.3 per 100 py (95% CI: 0.00-1.67) (Table). Pts used a mean of 18 pills/month and 39% acquired a new STI. There was no significant changes between the double-blinded phase and the open-label phase in the median number of sexual intercourses or sexual partners, but there was a significant decrease in condom use for receptive anal intercourse (p=0.0004). Safety was good with a low rate of serious adverse events (6% of pts) and a single participant discontinued TDF-FTC because of an increase in creatinine plasma level. Drug-related gastrointestinal adverse events (mainly nausea and diarrhea) were reported in 11% of pts.

IPERGAY phasePerson-years of follow-upIncidence of HIV Infection per 100 person-years [95% confidence interval]
IPERGAY double-blinded (Placebo Arm)2126.60 [3.61-11.07]
IPERGAY double-blinded (TDF-FTC Arm)2190.91 [0.11-3.30]
IPERGAY open-label extension (open-label TDF-FTC)3340.30 [0.00-1.67]
[Incidence of HIV infection according to IPERGAY phase]

Conclusions: Open-label on demand PrEP with oral TDF-FTC continued to be highly effective in high risk MSM to prevent HIV-infection and had a good safety profile.