When your US data isn’t enough for Europe

Written by HATEM RABEH, MD, MSc Ing

Your Clinical Evaluation Expert And Partner

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This happens more often than it should. Teams invest months collecting clinical data from non-EU markets, build what looks like a complete clinical evaluation, and then discover that geography actually matters under MDR.

The problem is not that foreign data is prohibited. The problem is that it’s often presented as if location were irrelevant.

It isn’t.

Why geography enters the regulatory equation

MDR Annex XIV Part A requires clinical data that is relevant to the EU population and EU clinical practice. This is not a suggestion. It’s an explicit requirement.

When you submit clinical data collected outside Europe, reviewers will immediately ask: Does this data reflect what happens here? Does it account for differences in patient characteristics, disease prevalence, treatment protocols, and healthcare infrastructure?

If you cannot answer these questions convincingly, the data becomes questionable regardless of its volume or quality.

Most manufacturers miss this. They assume that clinical evidence is universal, that a hip implant performs the same way in Dallas as it does in Dresden.

But the regulatory framework does not accept that assumption by default.

What makes data geographically relevant

Reviewers evaluate geographic relevance through several lenses. Understanding these helps you structure your justification properly.

Patient population characteristics

Are the patients in your study representative of EU patients who will use your device?

This includes demographics, comorbidities, disease severity, and baseline health status. If your US study excluded patients over 75, but your EU target population includes elderly patients with multiple conditions, that’s a gap.

If your study was conducted in a region with low prevalence of certain comorbidities common in Europe, that’s also a gap.

Clinical practice and care pathways

How is the device used in the healthcare system where the data was collected? Is that use comparable to EU practice?

Take a diagnostic device used in primary care settings in the US but deployed mainly in hospital laboratories in Europe. The user profile, training level, and quality control environment differ significantly.

Or consider a surgical device. If the US data comes from high-volume specialized centers but the device will be used in general hospitals across Europe, the skill level and procedural context are not the same.

These differences affect safety and performance outcomes. Reviewers know this.

Regulatory and standard of care differences

Some treatments are standard in one region but not in another. Some devices are used earlier in the care pathway in the US and later in Europe, or vice versa.

If your device is positioned differently in the clinical algorithm depending on geography, that affects the patient population, the disease stage at intervention, and the expected outcomes.

You cannot ignore this and expect the data to transfer seamlessly.

The regulatory expectation under MDR

MDR does not forbid the use of non-EU clinical data. But it requires you to demonstrate that this data is applicable to the European context.

MDCG 2020-6 on sufficient clinical evidence reinforces this. The clinical data must be relevant to the device, the indication, the patient population, and the intended conditions of use in the EU market.

If the data comes from outside the EU, you must provide a reasoned justification for its relevance. This means analyzing and documenting the comparison between the study context and the EU context.

What does that look like in practice?

It means creating a section in your CER that explicitly addresses geographic transferability. Not as an afterthought, but as a structured argument.

You compare patient demographics from your study to EU epidemiological data. You describe clinical practice in the region where the data was collected and compare it to EU guidelines and care pathways. You identify differences and explain why they do not undermine the applicability of the data.

This is not a formality. Notified Bodies and competent authorities scrutinize this carefully.

When foreign data alone is not enough

There are situations where even a well-justified foreign dataset will not satisfy the requirement for EU-relevant evidence.

If your device targets a condition with significant geographic variation in prevalence, severity, or treatment approach, foreign data may need to be supplemented with EU-specific data.

If your device interacts closely with local healthcare infrastructure, workflows, or training systems, you may need evidence from EU clinical settings to demonstrate real-world performance.

This is especially true for higher-risk devices or novel technologies where there is little prior experience in the EU market.

This does not always mean a full clinical investigation. It can be registry data, real-world evidence from early EU adopters, or targeted post-market studies.

But the expectation is there. And manufacturers who ignore it face repeated deficiencies and submission delays.

How to structure the justification

If you rely on foreign data, your CER must include a clear and systematic justification. Here is what that should cover:

1. Describe the source of the data

Where was the study conducted? What were the clinical sites? What type of healthcare setting?

Be specific. Don’t just say “US data.” Say whether it’s from academic medical centers, community hospitals, or private clinics. Context matters.

2. Compare patient populations

Use epidemiological references to compare the study population with the EU target population. Look at age distribution, comorbidity profiles, disease severity, and any other relevant factors.

If differences exist, explain them and argue why they do not compromise the applicability of the results.

3. Compare clinical practice

How is the device used in the study setting versus the EU? Are the indications the same? The contraindications? The user training requirements?

Reference EU clinical guidelines where available. Show that you understand the care pathway in Europe.

4. Acknowledge limitations and mitigation

If there are gaps, acknowledge them. Then explain how you plan to address them through PMCF, registries, or additional data collection in the EU.

Reviewers respect transparency. They do not respect pretending that limitations don’t exist.

What reviewers look for during assessment

When a Notified Body reviews your submission, they will ask:

Is the clinical data representative of EU patients and EU use conditions? If not, has the manufacturer justified why the foreign data is still applicable?

Are there known differences in disease epidemiology, treatment standards, or healthcare infrastructure that could affect device performance? Has the manufacturer addressed these?

Is there a plan to collect EU-specific data post-market if the pre-market evidence comes entirely from outside Europe?

If the answers are unclear or missing, you get a deficiency. And these deficiencies are not easy to close after the fact because they often require new data or analyses you didn’t plan for.

The role of PMCF in bridging geographic gaps

PMCF can play a strategic role when your pre-market data is predominantly foreign.

By designing a PMCF study or registry that specifically collects data from EU sites, you demonstrate commitment to confirming safety and performance in the European context.

This approach works well when you can show that the foreign data is sufficient for initial market access, but you recognize the value of EU-specific real-world evidence.

Notified Bodies often accept this if the PMCF plan is robust, targeted, and initiated early.

What they don’t accept is a vague promise to “monitor EU performance” without a concrete protocol and timeline.

Practical implications for submission strategy

If you are planning a submission with predominantly non-EU data, plan the geographic justification early. Don’t wait until the CER is drafted.

During clinical development, document the rationale for study locations. If you choose to conduct studies outside the EU, document why and how you will ensure EU applicability.

Involve clinical and regulatory affairs early to align on what evidence will be needed for different markets.

If you are already in the submission phase and realize you have a geographic gap, assess whether you can close it through literature, real-world data, or a targeted PMCF study.

But don’t assume you can wave it away with general statements. That strategy fails under MDR scrutiny.

Final thoughts

The requirement for EU-relevant clinical data is not bureaucratic. It reflects a reasonable expectation that medical devices should be evaluated in the context where they will be used.

Foreign data is valuable and often forms the backbone of clinical evaluations. But it must be presented with awareness of geographic context and justified accordingly.

Manufacturers who understand this build stronger submissions. Those who don’t face repeated deficiencies and delays that could have been avoided with better planning.

Geography matters under MDR. Not because regulators are parochial, but because clinical relevance is not universal by default.

Peace,
Hatem
Clinical Evaluation Expert for Medical Devices
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