HIV pre-exposure prophylaxis (PrEP): a review of current knowledge of oral systemic HIV PrEP in humans

Despite established HIV prevention strategies and broadly available diagnostic strategies in developed western countries, rates of HIV new infections remain high. Alternative strategies for HIV prevention, particularly among men who have sex with men (MSM), are crucial. HIV pre-exposure prophylaxis (PrEP) has been discussed as one additional option that this review seeks to explore.

An online search identifying PrEP-relevant literature from 1st January 2010 to 1st August, 2015 was performed.

The iPrEx study, first published in 2010, demonstrated a reduction in relative risk (RRR) of HIV seroconversion of 44 % for continuous PrEP with tenofovir disoproxil fumarate (TDF) and emtricitabine (FTC) in MSM. The efficacy of PrEP has been confirmed for continuous PrEP in the PROUD study and for intermittent PrEP in the IPERGAY study (RRR = 86 % in both studies). The PrEP was well tolerated in all studies, and the evolution of HIV resistance has been low. Compensatory increased sexual risk behavior was not observed in recent studies. In contrast to the high efficacy of risk reduction for HIV transmission in MSM, the results of TDF PrEP and TDF/FTC PrEP studies using microbicidal agents or pills among heterosexual women were different (RRR 6-75 %).

Continuous and intermittent PrEP demonstrated high efficacy in preventing HIV seroconversion, notably among MSM. PrEP was well tolerated. Adherence was critical for high efficacy in all studies. Further studies to evaluate implementation strategies and cost-effectiveness in different risk populations are needed as well as drug approval in Europe.