Strategy-embedded diffusion and policy reproduction: how China’s special access policies for drugs and medical devices evolve through three-tiered interactions

China’s special access policies for unapproved drugs and medical devices represent a key institutional innovation in its healthcare regulatory system. In recent years, tailored versions of this policy have been implemented in Hainan Lecheng, the Guangdong-Hong Kong-Macao Greater Bay Area (GBA), and Beijing Tianzhu, each exhibiting differentiated trajectories in institutional design and management mechanisms. This study identifies a pattern of policy evolution termed Strategy-Embedded Diffusion, a model wherein the central government does not mandate a uniform policy model, but strategically deploys this tool to different strategic regions in alignment with national objectives. To analyze this phenomenon, this study develops a three-tiered interactive framework encompassing central delegation, local innovation, and social feedback. A comparative case analysis reveals that: the central government delineates distinct scopes of authorization based on each region’s strategic positioning and risk tolerances; local governments engage in selective learning and institutional reproduction tailored to local conditions; and key societal stakeholders actively shape policy refinement through continuous feedback.