Real-time electronic drug monitoring: experiences from a multinational phase 3 clinical trial to prevent multidrug-resistant TB

Objective We describe the experience of implementing real-time electronic drug monitoring (EDM) within a clinical trial to prevent multidrug-resistant TB (MDR-TB) among high-risk household contacts. Methods The Protecting Households On Exposure to Newly Diagnosed Index Multidrug-Resistant Tuberculosis Patients (PHOENIx) trial is a phase 3, open-label, cluster-randomised clinical trial conducted in 31 sites in Africa, Asia, and Latin America. Household contacts of adults with MDR-TB were enrolled from June 2019 to January 2025, each receiving an EDM device to monitor adherence to TB preventive therapy. Here, we review selection of the adherence monitoring approach and key procedures implemented to support EDM use and oversight throughout the trial. Results Integrating EDM in the PHOENIx trial enabled objective monitoring and early non-adherence identification to ensure timely counselling. Dedicated effort was needed to develop, train, and implement standardised protocols, but overall coordination required relatively few staff. Technical issues were manageable, and monitoring costs were relatively low for a large trial. Conclusion Findings highlight the added value of objective adherence monitoring, which can inform future trials, particularly for prevention. Our experiences suggest that with the appropriate support, EDM can be used to monitor and characterise adherence, even in a complex multi-country phase 3 trial in settings with a high TB burden.