Why Your Pre-MDR Investigation May Not Satisfy MDR Requirements

Written by HATEM RABEH, MD, MSc Ing

Your Clinical Evaluation Expert And Partner

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This scenario repeats across submissions. Manufacturers assume that because they conducted a clinical investigation before May 2021, and because the study followed ISO 14155 and GCP principles, the data remains valid under MDR.

It often does not.

The issue is not the quality of the study. The issue is whether the study was designed to answer the questions the MDR now demands. And in most cases, it was not.

The Shift in Clinical Evidence Expectations

Under the old directives, a clinical investigation primarily addressed safety and performance. The endpoints were often defined by what was technically feasible to measure and what would satisfy CE marking requirements at the time.

The MDR changed the standard.

Article 61 and Annex XIV now require clinical evidence to demonstrate not only safety and performance, but also clinical benefit in the target population, under normal conditions of use. The evaluation must address whether the device achieves its intended clinical outcome, and whether the benefit-risk ratio remains acceptable throughout the device lifecycle.

A pre-MDR study designed to show non-inferiority to a predicate device on a surrogate endpoint may not answer these questions.

So what happens during review?

The Notified Body or competent authority looks at the investigation and asks: Does this study prove clinical benefit? Does it reflect the intended patient population? Does it address all significant hazards in the risk management file? Does it support the claims in the IFU?

If the answer to any of these is no, the clinical evaluation is considered insufficient. Even if the study itself was conducted flawlessly.

Where Pre-MDR Investigations Fall Short

There are predictable gaps. I see the same patterns in every review.

Endpoint Mismatch

Many pre-MDR studies used technical endpoints instead of clinical outcomes. For example, a cardiovascular device study measured procedural success but did not follow patients long enough to demonstrate reduced morbidity or mortality. A diagnostic device study showed correlation with a reference standard but did not link the result to a change in patient management or outcome.

Under the MDR, you must show that the device contributes to a clinically relevant benefit. A technical surrogate is not enough unless you can demonstrate that the surrogate predicts clinical benefit and that this link is scientifically valid for your device.

If your pre-MDR study only addressed the surrogate, you now need additional evidence to close the gap.

Population Mismatch

Another common deficiency: the study population does not match the intended use population.

Perhaps the investigation excluded patients with comorbidities to reduce variability. Perhaps it was conducted in a controlled academic center with highly experienced users. Perhaps it included only a subset of the indications now claimed in the IFU.

The MDR requires evidence that reflects real-world use. If your study population was narrower than your target population, the Notified Body will identify this as a gap. You will need to justify why the results are generalizable, or you will need to generate additional data.

Follow-Up Duration

Many pre-MDR investigations had short follow-up periods. Six months. One year. This was often sufficient under the directives, especially if the primary endpoint was an early outcome.

Under the MDR, follow-up duration must be justified based on the device lifecycle, the nature of the risks, and the time required to observe clinical benefit and late complications.

If your device remains in the body, if it has potential for long-term complications, if the claimed benefit requires sustained performance, your pre-MDR follow-up may not be long enough.

You cannot go back and extend the follow-up of a closed study. So you need to either conduct a new study with adequate duration or implement a PMCF study that prospectively collects the missing long-term data.

Incomplete Risk Coverage

Risk management files evolve. Hazards are added. Hazardous situations are refined. New risks are identified from post-market surveillance or literature.

If your pre-MDR investigation was designed before your current risk analysis, it may not have monitored all the risks that now appear in your risk management file.

This is a direct gap. The MDR requires that clinical evidence addresses all residual risks. If your investigation did not track a risk now identified as significant, you need additional evidence to demonstrate that the risk is acceptable.

What Notified Bodies Look For

When a Notified Body reviews a clinical evaluation built on a pre-MDR investigation, they perform a structured gap analysis.

They compare the study objectives, endpoints, population, and duration against the current MDR requirements and the claims in your technical documentation.

They check whether the investigation supports every performance claim in the IFU. They verify whether the study monitored every significant residual risk. They assess whether the benefit-risk conclusion is justified by the data presented.

If they find a mismatch, they issue a deficiency. And the deficiency is rarely solved by reinterpreting the old data. It requires new evidence.

This is why manufacturers are surprised. They believed their clinical investigation was their strongest evidence. But strength is relative to the question being asked.

How to Address the Gap

The solution depends on the nature and size of the gap.

If the Gap Is Narrow

If the mismatch is limited to a specific claim or a specific subgroup, you may be able to bridge the gap with literature, real-world data, or a targeted PMCF study.

For example, if your investigation demonstrated benefit in one indication but your IFU now claims a second related indication, you may justify the extension through literature and biomechanical reasoning, supported by post-market data showing safe use in the broader population.

This approach works when the extension is scientifically reasonable and the risk profile does not significantly change.

If the Gap Is Wide

If the pre-MDR investigation does not address the primary clinical benefit claimed, or if it excludes a large portion of your target population, you likely need a new clinical investigation or a robust PMCF study designed to fill the gap.

This is not a minor adjustment. It requires protocol development, ethical approval, patient enrollment, and often years of follow-up.

Manufacturers who discover this gap late in the certification process face delays. The earlier you identify the gap, the earlier you can plan the evidence generation strategy.

PMCF as a Complement, Not a Substitute

Some manufacturers assume that a PMCF plan can solve any clinical evidence gap.

It cannot.

PMCF is required under Article 61 and Annex XIV Part B to confirm safety and performance throughout the lifecycle. It is not a replacement for pre-market clinical evidence.

If your pre-market evidence is insufficient to demonstrate clinical benefit, you need to generate that evidence before or during the conformity assessment. PMCF can complement and confirm, but it cannot be the sole source of evidence for a core claim.

The Role of the Clinical Evaluation Report

The clinical evaluation report is where the gap becomes visible or hidden.

If the report transparently identifies the limitations of the pre-MDR investigation and explains how additional evidence addresses those limitations, the Notified Body can assess the overall sufficiency of the clinical evidence.

If the report presents the pre-MDR investigation as complete evidence without acknowledging the gaps, the deficiency will be flagged immediately.

This is why the appraisal section of the CER is critical. You must evaluate not only the quality of each piece of evidence, but also its relevance to the current MDR requirements and the current device claims.

Relevance is not binary. A study can be partially relevant. The appraisal must clearly state what the study demonstrates and what it does not demonstrate. Then the report must show how the remaining questions are answered by other evidence.

Practical Implications for Regulatory Strategy

If you have a pre-MDR clinical investigation, you should conduct a gap analysis as early as possible.

Compare the study protocol, endpoints, population, and follow-up against your current risk management file, IFU claims, and MDR requirements. Identify any mismatches.

Then decide whether those gaps can be bridged with existing evidence or whether new data generation is required.

If new data is required, plan it now. Waiting until the Notified Body identifies the gap will delay your certification by months or years.

This is not theoretical advice. I see this delay pattern in every review cycle. The manufacturers who succeed are the ones who anticipated the gap and started evidence generation early.

What This Means Going Forward

The MDR did not make pre-MDR investigations obsolete. It made them insufficient as standalone evidence in many cases.

The regulatory environment now demands evidence that explicitly demonstrates clinical benefit, covers the full intended population, addresses all significant risks, and provides adequate follow-up duration.

If your pre-MDR investigation meets all these criteria, you are in a strong position. If it does not, you need a plan to fill the gaps before or during the conformity assessment process.

This is not a problem unique to your device. This is a structural challenge affecting most devices transitioning from the directives to the MDR.

The manufacturers who navigate it successfully are the ones who treat clinical evaluation as a living process, not a historical document.

Your pre-MDR investigation is valuable evidence. Just make sure you know exactly what it proves and what it does not prove. Then build your evidence strategy accordingly.

Peace,
Hatem
Clinical Evaluation Expert for Medical Devices
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