Abstract Body

Effectiveness of Post exposure prophylaxis (PEPSE) correlates with speed of uptake following HIV exposure. Time taken travelling to and obtaining PEPSE at sexual health/ emergency units can reduce efficacy and prevent people accessing PEPSE. We hypothesized that advanced provision of a 5-day PEP starter pack (HOME PEPSE) for men who have sex with men (MSM) to keep at home and self- initiate if required, would reduce time to first dose following HIV exposure, but not impact HIV risk behavior.

Phase IV, randomised, prospective, open label, study. MSM at medium risk of acquiring HIV were randomized (1:1) to immediate (ARM A) or deferred (ARM B) Home PEPSE. Duration of study was 48 weeks (Arm A) and 72 weeks for (Arm B) who accessed PEPSE through standard of care from week 0-48 and received HOME PEPSE week 48-72. Every 12weeks, participants self- completed mental health/ risk behaviour surveys and had HIV/STI testing. HOME PEPSE comprised a 5-day pack of FTC-TDF/Maraviroc taken following potential exposure to HIV. Upon uptake, participants completed a risk questionnaire; PEPSE continuation was physician directed. Appropriate uses of PEP were included in primary analysis. Time to first dose between treatment arms was compared using a two-sided Mann-Whitney U test.

139 participants were randomised: 69 (ARM A) and 70 (ARM B). Median age 30years [IQR: 26-39], 75% white, 55% UK born and 72% university educated. 33 in ARM A and 15 in ARM B were eligible for primary analysis. Median time from exposure to first dose was 7.6 hours [3.0,20.9] for ARM A and 28.5 hours [17.3,34.0] for ARM B (p < 0.01). The most reported reason for PEPSE uptake was receptive anal sex with a man of unknown HIV status (81% cases). Uptake of HOME PEPSE was appropriate in 29/ 33 cases (88%, 95% CI: 73-95%). ARM B had almost double the number (same median and IQR) of missed opportunities for PEPSE uptake than ARM A (268 versus 474 :p=0.625): 9/12 (75%) participants reporting >10 missed opportunities for PEP were in ARM B. No change in number of condomless anal sex acts in previous 3 months from week 0 to 48 in Arm A or arm B (512 versus 911: p = 0.215). One person in Arm B acquired HIV. HOME PEPSE was well tolerated.

HOME PEPSE was taken appropriately by MSM, and dramatically reduced time from exposure to first dose, with no impact on safety. Furthermore, HOME PEP may reduce number of missed opportunities for PEPSE. This approach may be incorporated into HIV prevention guidelines.