Prescription Digital Therapeutics as Living Interventions: Rethinking Evidence, Dosage, and Regulation in Adaptive Medicine.

Prescription digital therapeutics (PDTs) are transforming healthcare by delivering evidence-based interventions through adaptive software platforms. Unlike traditional therapies, PDTs can evolve after deployment through updates and user-driven modifications, challenging conventional models of evidence generation, dosage definition, and regulatory oversight. This editorial argues that PDTs should be conceptualized as "living interventions," requiring new frameworks that account for their dynamic nature. Key challenges include the absence of standardized definitions for digital "dose," variability in patient engagement, and the difficulty of measuring outcomes in continuously evolving systems. Additionally, the transition of therapeutic care into digital environments raises questions about maintaining therapeutic alliance and patient trust. Existing regulatory pathways, designed for static medical products, are insufficient for technologies that change over time. We propose the need for interdisciplinary and anticipatory approaches that integrate clinical science, engagement science, regulatory innovation, and implementation strategies. Ethical considerations, including equity, data privacy, and access, must remain central to ensure that PDTs enhance rather than widen healthcare disparities. As digital therapeutics continue to expand, aligning adaptability with accountability will be critical to their safe, effective, and equitable integration into modern healthcare systems.