PrEP demonstrates more protection than expected in real-life setting
SEATTLE — In a real-world setting, pre-exposure prophylaxis conferred even higher levels of protection against HIV among men who have sex with men than previously observed in placebo-controlled trials, according to data from the PROUD study, presented at CROI 2015.
“Our concerns about PrEP being less effective in the real world were unfounded,” Sheena McCormack, MD, senior clinical scientist in the MRC Clinical Trials Unit at University College London, said during her presentation. “MSM incorporated PrEP into existing risk reduction strategies, which continued to include condom use. Clinics were able to adapt routine practice to incorporate PrEP.”
McCormack and colleagues conducted a pragmatic, open label, randomized trial of PrEP that included 545 HIV-negative MSM. They were randomly assigned to receive immediate PrEP with Truvada (tenofovir/emtricitabine, Gilead Sciences) or deferred PrEP 12 months later. The participants were followed quarterly.
There were 22 infections overall over 453 person-years of follow-up, resulting in an incidence rate of 4.9 per 100 person-years. Three infections occurred in the immediate PrEP group over 239 person-years of follow-up, compared to 19 infections over 214 years of follow-up in the deferred PrEP group. The incidence rate in the immediate PrEP group was 1.3 per 100 person-years, vs. 8.9 per 100 person-years in the deferred group. Immediate PrEP demonstrated relative risk reduction of 86% compared with deferred PrEP (P = .0002).
The proportion of confirmed STDs indicative of condomless anal intercourse was similar in both groups. Despite this, McCormack noted that the number of STD screens for rectal gonorrhea and chlamydia differed between the groups, with 974 men in the immediate PrEP group and 749 in the deferred PrEP group screened. There was also no difference in the number of condomless anal sex partners, either receptive or insertive, between the two groups.
“HIV incidence in the population who came forward to access PrEP was much higher than predicted based on all MSM attending sexual health clinics and despite extensive use of post-exposure prophylaxis in the deferred period,” McCormack said. – by Emily Shafer
McCormack S, et al. Abstract #22. Pragmatic Open-Label Randomised Trial of Preexposure Prophylaxis: The PROUD Study. Presented at: Conference on Retroviruses and Opportunistic Infections; Feb. 23-26; Seattle.
Disclosure: McCormack has received grants from Gilead Sciences, who has also provided medicines, equipment or administrative support.