Clinical Evaluation in Japan: When a Local Trial Is Required

1. Key takeaways

Japan does not require a local clinical trial for every device. The deciding criterion is whether applicability to the Japanese population can be argued from existing evidence. The decision tree has three branches: where a Japanese existing approved product exists and equivalence can be argued, literature and non-clinical evidence carry the file; where overseas data are usable but extrapolation must be argued, bridging evidence is added as circumstances require; where novelty is high or extrapolability is insufficient, a Japanese local trial is needed. GRZAN recommends moving this judgment forward into PMDA pre-submission consultation, rather than being forced to add studies passively after submission.

• The first branch: an existing approved product in Japan plus a supportable equivalence argument allows the dossier to rest mainly on literature and non-clinical evidence.
• The second branch: overseas clinical data are usable in principle, but their extrapolability to Japan must be argued, with bridging evidence added where needed.
• The third branch: high novelty or insufficient extrapolability leads to a requirement for a Japanese local trial.
• Acceptability of overseas data and extrapolability to the Japanese population are two distinct questions; failure usually occurs on the second.
• Conditional approval, effective May 1, 2026, adds an alternative path for products where conventional clinical development is difficult; documenting the rationale for each branch keeps the pathway choice auditable later.

2. Legal basis

The clinical evidence requirements for approval derive from the review criteria in the PMD Act, the Medical Device GCP Ordinance governing trial conduct, and the newly introduced conditional approval scheme. The key sources are as follows.

• PMD Act Article 23-2-5, Paragraph 2: the criteria for review judgment on approval, including the judgment of quality, efficacy and safety.
• Ordinance on the standards for conducting clinical trials of medical devices (Medical Device GCP Ordinance), MHLW Ordinance No. 36 of 2005 (Heisei 17); last amended by MHLW Ordinance No. 128 of 2016 (Heisei 28).
• PMD Act Article 23-2-9: post-marketing performance evaluation — the institutional arrangement under which post-marketing studies supplement insufficient pre-market evidence.
• PMD Act Article 23-2-6-2 (newly established by Act No. 37 of 2025, promulgated May 21, 2025, effective May 1, 2026): conditional approval, providing an alternative path for products that are difficult to develop clinically.
• Current statute: Act No. 145 of 1960.

3. Expert insights

Insight 1: Acceptability and extrapolability are two different questions.

Two premises must hold before overseas clinical data are accepted in Japan: the trial itself must comply with GCP or an equivalent or stricter standard, and the data must be extrapolable to the Japanese population and Japanese medical practice. The first premise is a compliance question; the second is a question of scientific argumentation. Manufacturers commonly resolve only the first — they can show that the trial followed a recognized GCP standard — and it is precisely on the second that submissions are returned. Extrapolation must be demonstrated, not assumed: differences in patient demographics, clinical pathways, usage patterns, and operator training all bear on whether overseas results describe what will happen in Japanese clinical settings. A dossier that argues both premises explicitly is materially stronger than one that only certifies trial conduct.

Insight 2: The decision tree ends not only at running a trial, but also at conditional approval.

Conditional approval, effective May 1, 2026, provides a fourth path for products where an effect or performance can be reasonably predicted but conventional clinical development is difficult to complete. This is a statutory alternative, not an informal concession. GRZAN recommends evaluating this path as an independent branch of the decision tree, in parallel with the conventional routes, rather than defaulting to the assumption that a full trial must be completed in every case. Where the product profile fits the conditional approval scheme, the evaluation should be made deliberately and documented, so that the choice of pathway is a considered regulatory decision rather than an omission in planning.

Insight 3: Post-marketing performance evaluation can carry part of the evidence supplementation function.

Article 23-2-9 allows post-marketing studies to be attached as a condition accompanying approval. For certain products, the part of the evidence base that is insufficient before approval can be addressed through the design of the post-marketing study. This is not a loophole but a structured arrangement, and it works only when the study design has been agreed with the reviewers in advance. Presenting a post-marketing evaluation plan as part of the submission — rather than after a deficiency is raised — converts an open question into a negotiated term of the approval.

4. Practical recommendations

• Complete pre-submission consultation on the clinical pathway before filing. Make the question of whether a Japanese local trial is required one of the core topics of the consultation.
• Build an extrapolation argumentation package for overseas data. Cover ethnic differences, Japanese clinical pathways, usage habits, and differences in operator training.
• Evaluate the applicability of conditional approval. For products where a large-scale randomized controlled trial is difficult to conduct, assess this path in parallel with the conventional route.
• Where a local trial involving Japanese subjects is needed, build the trial system under the Medical Device GCP Ordinance. The requirements of MHLW Ordinance No. 36 of 2005 must be implemented before trial initiation.

5. Verification checklist

• □ Has PMDA pre-submission consultation been completed on whether a Japanese local clinical trial is required?
• □ Has an extrapolation argumentation package (ethnicity, clinical pathways, usage habits) been prepared for overseas data?
• □ Has the feasibility of conditional approval been evaluated as an alternative pathway?
• □ If a local trial is required, has the trial system been established in accordance with MHLW Ordinance No. 36 of 2005?
• □ Has post-marketing performance evaluation been included in the assessment as an evidence supplementation option?

Legal information verified as of October 29, 2026.

How GRZAN can help. GRZAN provides medical device and IVD registration, quality system, in-country representative and local testing support for the Japanese market. Our team prepares J-GCP/J-QMS compliant dossiers, coordinates conformity assessments, and supports post-market vigilance obligations. Business enquiries: info@grzanglobal.com