BACKGROUND:
Young men who have sex with men (YMSM) experience disparities in HIV acquisition more than any other group. Daily oral pre-exposure prophylaxis (PrEP) with tenofovir/embricitabine (TDF/FTC) has been shown to effectively prevent HIV transmission in YMSM; however, recent studies suggest that young Black men who have sex with men (YBMSM) experience sub-protective levels of tenofovir diphosphate (TFV-DP) more frequently than other groups.

SETTING:
Combined data from Adolescent Medicine Trials Network for HIV/AIDS Interventions (ATN) 110/113, two open label PrEP studies that provided PrEP and evidence-based behavioral interventions to young MSM (YMSM) age 15 to 22 years old.

METHODS:
Bivariate and logistic regression analysis were used to examine sociodemographic and behavioral factors associated with protective TVF-DP levels (defined as ≥700 fmol/punch) in ATN 110/113 data.

RESULTS:
In bivariate analysis, self-identified Black participants, residential displacement due to sexual orientation, low perceived risk, and stigma with the medication were associated with sub-protective levels. Hispanic ethnicity was associated with protective levels. In the final models, Black males were less likely to have sub-protective levels than non-Black males at 4, 8, 12 weeks. Self-reported displacement due to sexual orientation was associated with sub-protective levels while older age was as associated with protective levels.

CONCLUSION:
These findings highlight how future behavioral research and biomedical prevention efforts in YMSM will need to address PrEP disparities that may occur in YBMSM, perception of risk and lack of key supportive housing during this period that may be critical factors that contribute to HIV acquisition.