Acceptability of Foreign Clinical Data
Japan has historically required Japan-specific clinical data for many device categories, particularly for higher-risk devices. However, PMDA and MHLW have progressively expanded acceptance of foreign clinical data as part of broader IMDRF harmonisation efforts and to address the so-called "device lag" — the delay in innovative devices reaching Japanese patients compared to the US and EU.
When foreign clinical data is accepted
PMDA's acceptance of foreign clinical data depends on:
Whether the device is truly novel. For well-established technologies (e.g. a new model of an established device type), foreign clinical data supporting the predicate or reference device is typically accepted without a Japan-specific trial.
Whether differences between Japanese and foreign patient populations are clinically relevant. PMDA is primarily concerned with whether there are anatomical, physiological, genetic, or disease-prevalence differences between Japanese patients and the foreign study population that could affect the device's safety or efficacy in Japan.
The quality and completeness of the foreign data. Foreign studies must have been conducted under GCP-equivalent standards and must provide adequate data to support the Japanese application.
Whether PMDA has accepted foreign data for the same device type previously. Published precedents from previous PMDA reviews of similar devices give strong guidance.
Bridging data requirements
Where PMDA accepts foreign data but requires some Japan-specific confirmation, bridging data may be requested. Bridging data can include:
- A Japan-specific sub-study embedded within a global trial
- A limited Japan-only registry or cohort study
- Literature data from Japanese clinical practice
The specific requirements should be confirmed with PMDA through a pre-submission consultation before the data collection plan is finalised.
Japanese patient population considerations
PMDA is particularly attentive to potential population differences for:
- Cardiovascular devices — Japanese patients have different coronary artery dimensions (generally smaller vessel diameter) that can affect stent sizing and outcomes
- Orthopaedic implants — differences in bone geometry and patient BMI distribution
- Devices where disease prevalence differs — e.g. hepatic and gastric disease patterns differ from Western populations
Where population differences are not clinically significant, PMDA will accept foreign data. PMDA has published guidance on several device categories specifying whether Japan-specific data is required.
PMDA guidance on foreign data reliance
PMDA has published multiple guidance documents and notifications on the acceptability of foreign data. The most relevant are available (in Japanese) from PMDA's website. Key principle: engage PMDA early to get specific guidance for your device and study population before designing your clinical programme.