Feasibility of an Ingestible Sensor System to Measure PrEP Adherence in YMSM

In order to evaluate the feasibility and acceptability of the PSS for FTC/TDF PrEP, 100 HIV-negative YMSM will be randomized in the Advances in Technology to Enhance Adherence Monitoring (A-TEAM) pilot study to 12 weeks of daily FTC/TDF with the PSS versus daily FTC/TDF standard-of-care (SOC), then each arm will crossover to 12 weeks of daily FTC/TDF without the sensor system versus with the sensor system, respectively. PrEP will be provided by the study (see Gilead letter) and other aspects of PrEP clinical care will be consistent with the PrEP Clinic's standard practices based on CDC clinical guidelines. The detection accuracy of the PSS will be correlated with DBS-determined TFV-DP and FTC-TP levels obtained monthly from participants. A relationship between TVF-DP in DBS and adherence to FTC/TDF PrEP in the preceding 1-3 months has previously been characterized. These adherence categories were implemented in iPrEx OLE and consisted of: below lower limit of quantitation (BLQ), \>BLQ to 349 fmol per punch (fewer than two tablets per week), 350-699 fmol per punch (two or three tablets per week), 700-1249 fmol per punch (four to six tablets per week), and 1250 fmol per punch or more (daily dosing). Real-time visual feedback of medication ingestion will be provided to the participant via the PSS and transmitted to the study team. A weekly text message with estimated HIV risk reduction based upon the DBS algorithm will be transmitted to participants after the initial first week of FTC/TDF dosing. Finally, in-depth qualitative exploration of barriers and facilitators to use of the PSS components will be completed through individual interviews as well as focus group discussions with participants. Participants will also provide feedback on text messages regarding PrEP protection as well as suggestions for other potential methods to receive performance data.