Sexual Risk Compensation and Retention in PrEP Care in Korea: An HIV PrEP Demonstration Study.

Background: Pre-exposure prophylaxis (PrEP) with tenofovir disoproxil fumarate and emtricitabine (TDF-FTC) is effective in preventing human immunodeficiency virus (HIV), however, its feasibility has not been evaluated in the Republic of Korea (Korea). Therefore, this study aimed to assess the feasibility of PrEP in men who have sex with men (MSM) in Korea. This is the first demonstration study in Korea, in which PrEP medication, laboratory tests, and clinic visit fees were provided without charge to participants.

Methods: HIV-negative MSM were prescribed daily TDF-FTC and followed up at an outpatient clinic. At each visit, adverse reactions, adherence, and sexual behavior were assessed using a questionnaire, and residual pills and blood and urine samples were collected. Tenofovir diphosphate (TFV) concentrations were measured in plasma and urine.

Results: One hundred participants were enrolled and followed up for a median of 392 days. The retention-in-care was 77%. The incidence of HIV and other sexually transmitted infections (STIs) was 0.98 and 13.67 per 100 person-years, respectively. No serious adverse events were detected. Among the participants, 55.3% (47/85) and 41.7% (25/60) had plasma TFV concentrations > 40 ng/mL at weeks 28 and 52, respectively. Residual pill counts and self-reported adherence were not correlated with plasma TFV levels. Participants with positive STI test results were significantly more likely to have plasma TFV concentrations > 40 ng/mL (adjusted odds ratio, 3.67; P = 0.034). The reported proportion of episodes of non-condom receptive anal intercourse decreased during the study.

Conclusion: Daily oral PrEP was safe and effective in MSM and not associated with increased sexual risk behavior. To our knowledge, this is the first analysis of risk compensation among PrEP users in East Asia.