Design and Delivery of Real-Time Adherence Data to Men Who Have Sex with Men Using Antiretroviral Pre-exposure Prophylaxis via an Ingestible Electronic Sensor.

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.

Long-Term Stability of the Electronic Sensor Component of a Digital Pill System in Real-World Storage Settings.

Background: Digital pill systems comprise an ingestible sensor integrated into a gelatin capsule that overencapsulates medication allowing real-time measures of medication ingestion. These systems may improve the manner in which medication adherence can be assessed and supported. Objective: In this investigation, we tested the durability of the ingestible sensor as part of a clinical trial to measure the feasibility and acceptability of the system to measure adherence to once daily tenofovir disoproxil fumarate/emtricitabine (NCT03842436). Methods: Digital pills not dispensed during the study were stored in a pharmacy. Seventeen sensors were selected from digital pills stored for at least 12 months and activated in a simulated gastric environment. A radiofrequency spectrum analyzer and the reader device used in the clinical trial to capture ingestion events were used to measure activation of emitters. A passing evaluation was defined as an energized emitter within 30 minutes of immersion, ability to broadcast a signal for 10 minutes, and successful acquisition by the reader. Results: All ingestible sensors passed the stability test. Mean activation time in simulated gastric fluid was 3.33 minutes (SD = 1.47); emitters remained active for a mean of 47.72 minutes (SD = 1.78). These parameters matched guidelines defined in the ID-Cap system requirements for use in patients. Conclusions: Ingestible sensor components of the ID-Cap system were therefore stable after long-term storage.