§01
How PMDA regulates AI-enabled SaMD
AI SaMD is approved under the Pharmaceuticals and Medical Devices Act (PMD Act) through the standard medical device classification (Class I–IV). PMDA's review references IMDRF SaMD risk categorisation and the agency's own software guidance, with AI-specific expectations layered on via the Science Board report. Premarket evidence centres on dataset description, performance against a locked test set, and a clearly defined intended use within the Japanese clinical environment.
- Classification follows IMDRF SaMD logic; most diagnostic AI lands Class III or IV.
- Premarket dossier expects dataset provenance, exclusion criteria, and subgroup performance.
- Japanese-population validation is expected for diagnostic AI; foreign-only cohorts are rarely sufficient.
- Cybersecurity expectations align with IMDRF and reference Japanese industry standards (JIS).
§02
IDATEN and the Confirmation of Change Plans pathway
IDATEN lets a manufacturer pre-define which changes to an approved device · including ML model retraining · can be executed under a Confirmation of Change Plan (CCP) without a full re-application. The September 2025 expansion broadened scope to program medical devices and clarified the AI-specific workflow: the change plan, the impact assessment, and the post-implementation reporting expectations now sit in one consolidated framework.
- Define the Change Plan at initial approval: which parameters can move, within which bounds.
- Specify the protocol · data, retraining, validation, deployment · that governs each change.
- Submit a CCP application; once confirmed, execute changes and report under the agreed cadence.
- Material changes outside the plan still require a partial change application (ichibu henkō).
§03
Where PMDA aligns and where it diverges
PMDA aligns closely with IMDRF, FDA and MHRA on the principles · GMLP, lifecycle thinking, transparency. It diverges on execution: the CCP/IDATEN package must be authored in Japanese, the change plan is more prescriptive than an FDA PCCP, and the local clinical data expectation is firm. A US PCCP is a useful starting artefact, not a deliverable.
§04
Practical posture
Treat IDATEN/CCP as a strategic asset, not a paperwork exercise. The agencies that have approved AI SaMD in Japan over the last three years almost all have a change plan on file. Plan the Japanese clinical evidence early, invest in a local regulatory partner who can translate and negotiate the CCP, and build your post-market monitoring so it produces the artefacts PMDA expects to see.