Once daily tenofovir/emtricitabine when used for pre-exposure prophylaxis (PrEP) is effective in preventing HIV acquisition but requires consistent medication adherence. The use of ingestible technologies to monitor PrEP adherence can assist in understanding the impact of behavioral interventions. Digital pill systems (DPS) utilize an ingestible radiofrequency emitter integrated onto a gelatin capsule, which permits direct, real-time measurement of medication adherence. DPS monitoring may lead to discovery of nascent episodes of PrEP nonadherence and allow delivery of interventions that prevent the onset of sustained nonadherence. Yet, the acceptance and potential use of DPS in high-risk men who have sex with men (MSM; i.e., those who engage in condomless sex and use substances) is unknown. In this investigation, we conducted individual, semi-structured qualitative interviews with 30 MSM with self-reported non-alcohol substance use to understand their responses to the DPS, willingness and perceived barriers to its use, and their perceptions of its potential utility. We also sought to describe how MSM would potentially interact with a messaging system integrated into the DPS. We identified major themes around improved confidence of PrEP adherence patterns, safety of ingestible radiofrequency sensors, and design optimization of the DPS. They also expressed willingness to interact with messaging contingent on DPS recorded ingestion patterns. These data demonstrate that MSM who use substances find the DPS to be an acceptable method to measure and record PrEP adherence.
Keywords: Digital pill system; HIV prevention; Ingestible sensors; PrEP; Technology.