Abstract

Gene therapy development in Japan involves a complex combination of regulatory activities spanning the Cartagena Act, nonclinical safety, chemistry, manufacturing and controls (CMC), and clinical trial design. Although these areas are addressed through separate consultations by the Pharmaceuticals and Medical Devices Agency (PMDA), they are closely interdependent through shared data, sequencing and regulatory communication.

This article introduces the SYNAPSE Model, an experience-based framework for understanding and strategically managing these interdependencies. It examines how data generated across development activities can support multiple consultations, how consultation sequencing can influence clinical trial timelines, and how consistent communication and regulatory positions can help prevent misalignment.

Drawing on the authors’ experience of gene therapy development in Japan, it also outlines practical approaches for mapping, identifying, sequencing and aligning regulatory activities. By treating PMDA consultations as an integrated regulatory network rather than isolated activities, sponsors can improve regulatory predictability, reduce avoidable additional studies or consultations, and support more efficient Japanese and global development strategies.