Potential role of PEP, PrEP and ART for HIV Prevention among Men who have Sex with Men Frits van Griensven, PhD, MPH Division of HIV/AIDS Prevention US Centers for Disease Control and Prevention and Thailand MOPH - US CDC Collaboration Disclaimer: The views expressed herein are solely the responsibility of the author and do not necessarily represent the official views of the CDC

In this presentation 1) Non-occupational (or sexual) post exposure prophylaxis (NPEP) 2) Pre-post exposure prophylaxis or PrEP Oral Topical 3) Antiretroviral treatment for prevention

Number of weekly rectal exposures % Uninfected macaques Controls (n = 21) FTC/TFV daily (n=6) FTC/TFV -2h/+22h (n=6) (HR>20, p<0.0001) Efficacy of daily and pre- and post-exposure oral Truvada in preventing SHIV infection following rectal challenge in macaques (HR>20, p<0.0001) Garcia-Lerma et al, PLOS, 2008

PrEP Initiative (iPrEx)  Men who have sex with men  Randomized 1:1 FTC/TDF vs Placebo  Daily oral  Followed for: HIV seroconversion Adverse Effects Metabolic Effects HBV exacerbations Risk behavior and STIs (including HSV) Adherence If infected  Drug resistance  Viral load  Immunological responses and CD4 counts

Intermittent PrEP (iPrep)  May be more in line with sexual life style  Reduce pill burden  Reduce drug burden  Reduce side-effects  Decrease costs  May increase adherence and coverage  And may be increase safer sex behavior  And is supported by animal models

In the shadow of Caprisa

Challenges for ARV prevention in MSM  Adherance  Risk compensation and behavioral disinhibition, individually and at the community level  Targeting and duration of programs  Programming outside the Western world  Implementation and programming in low HIV prevalence communities  Costs and competition with curation  Pill burden, drug burden, side-effects, toxicity, resistance  How to monitor impact

In conclusion  PEP not ready for programmatic scale up, but good as an individual service on a case by case basis  Daily PrEP results expected soon; if efficacious, studies will try to identify non-inferior alternative regimens  Many implementation issues  Rectal PrEP – promising, but still long way to go  ART for prevention, seems reasonable, ecological evidence available, MSM transmission studies are urgently needed