When Equivalence Saves You—and When It Destroys Your File

Written by HATEM RABEH, MD, MSc Ing

Your Clinical Evaluation Expert And Partner

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This happens more often than it should. Manufacturers choose the equivalence route because it sounds efficient. No clinical trials. No long recruitment periods. Just demonstrate equivalence to a device with existing clinical data and move forward.

But equivalence is not a shortcut. It is a regulatory pathway with strict technical and documentary requirements. And when those requirements are not met, the file does not get approved. It gets rejected with findings that force you back to square one.

The real question is not whether equivalence is easier. The question is whether it is appropriate for your device—and whether you can meet the burden of proof.

What the MDR Actually Requires for Equivalence

Equivalence is defined in MDR 2017/745 Annex XIV, Part A. To claim equivalence, you must demonstrate that your device and the equivalent device are similar in three areas: technical characteristics, biological characteristics, and clinical characteristics.

The regulation is clear. Similarity is not identity. But similarity must be sufficient that both devices can be expected to perform in the same way clinically.

MDCG 2020-5 adds operational detail. It states that equivalence must be supported by a comparative analysis. This analysis must cover design, materials, intended purpose, safety profile, and performance data. Any differences must be justified and shown not to affect clinical safety or performance.

Here is what reviewers focus on when they assess equivalence claims:

• Is the equivalent device still on the market under MDR or a valid MDD certificate?
• Do you have access to the full technical and clinical data of that device?
• Have you documented every difference between the devices?
• Have you shown that those differences do not introduce new risks or affect clinical outcomes?

If any of these points fail, the equivalence route fails.

Why Equivalence Is Not Always an Option

Some manufacturers assume equivalence is always available. It is not.

If your device introduces a new mechanism of action, a new material in contact with tissue, or a new intended purpose, equivalence becomes difficult or impossible to justify.

If the predicate device does not have sufficient clinical data, equivalence does not solve your problem. You inherit the data gap.

If the predicate device is no longer on the market or has been subject to field safety corrective actions, equivalence is not acceptable.

Equivalence works when the devices are genuinely similar and when the predicate has a solid clinical history. Outside of that, you are building on a weak foundation.

I have seen manufacturers try to claim equivalence to devices that were withdrawn from the market. I have seen claims based on devices that were Class IIa under the MDD but are now Class IIb under MDR. The risk profile changed. The clinical data requirements changed. Equivalence no longer applies.

The Hidden Cost of a Failed Equivalence Claim

When an equivalence claim is rejected, the consequences are not minor.

You do not just revise a section of the clinical evaluation report. You lose the entire evidentiary foundation. You must now generate your own clinical data, which means planning a clinical investigation, getting ethics approval, recruiting patients, and collecting follow-up data.

That can add 18 to 36 months to your timeline. It can add hundreds of thousands of euros to your budget. And it can delay market access in multiple jurisdictions.

But the regulatory impact is worse. A rejected equivalence claim signals to the Notified Body that your clinical strategy was not sound. It raises questions about your understanding of the regulatory requirements. It increases scrutiny on the rest of your technical file.

This is why the decision between equivalence and own clinical data must be made carefully at the beginning of the project—not after the first major finding.

When Own Clinical Data Becomes Necessary

Own clinical data means you generate evidence directly from your device. This can be through a clinical investigation, or through systematic post-market clinical follow-up that produces new evidence.

MDR requires own clinical data in specific situations:

• When equivalence cannot be demonstrated
• When the device is Class III or implantable Class IIb
• When the device contains a medicinal substance or is manufactured using non-viable tissues
• When SOTA shows that similar devices have encountered safety or performance issues that are not fully understood

Own clinical data is not optional in these cases. It is a regulatory requirement.

But even when equivalence is technically possible, own clinical data may be the better strategic choice.

If you are entering a competitive market, own data differentiates your device. If you are planning to expand indications or patient populations, own data gives you flexibility. If you are building a device platform for future iterations, investing in a clinical study early avoids repeated equivalence battles later.

Own clinical data is slower and more expensive upfront. But it gives you control. You are not dependent on someone else’s dataset. You are not vulnerable to changes in the predicate device’s regulatory status. And you generate evidence that can support future development.

How to Make the Choice

The decision between equivalence and own clinical data should follow a structured assessment:

Step 1: Identify potential equivalent devices. Search for devices with the same intended purpose, similar design, and comparable risk profile. Check their regulatory status. Confirm they are still marketed under valid certificates.

Step 2: Conduct a preliminary technical comparison. Compare materials, design features, mechanisms of action, and performance specifications. Document every difference.

Step 3: Assess access to data. Determine whether you can obtain the full technical documentation and clinical data for the equivalent device. Without access, equivalence is not feasible.

Step 4: Evaluate clinical data sufficiency. Review the clinical data available for the equivalent device. Is it sufficient under current MDR standards? Does it address your intended use and patient population?

Step 5: Assess risk of rejection. If there are significant differences, or if the equivalent device has a weak clinical dataset, the risk of rejection is high. In that case, plan for own clinical data from the start.

This assessment should be documented in the clinical evaluation plan. It should be reviewed with your Notified Body early in the conformity assessment process.

What Happens During Notified Body Review

Notified Bodies are trained to scrutinize equivalence claims. They know that equivalence is often used inappropriately.

During the review, they will ask for the equivalence report. They will check whether the technical comparison is detailed and whether differences are justified. They will verify that you have access to the data you are relying on.

They will also check whether the equivalent device itself meets current MDR requirements. If the equivalent device was certified under MDD and has not yet transitioned to MDR, that creates a problem. The data may not meet the stricter MDR standards.

If any element is missing or weak, the Notified Body will issue a finding. You will need to provide additional justification or additional data. If that is not possible, the equivalence route will be rejected.

This is not about being difficult. This is about ensuring that the clinical evidence supporting your CE mark is valid.

Final Considerations

Equivalence and own clinical data are not opposing strategies. In some cases, you may use both.

You may demonstrate equivalence for the core device function and generate own clinical data for a specific patient subgroup or a novel feature. You may start with equivalence and plan a PMCF study that produces own data over time.

What matters is that the strategy is intentional, documented, and aligned with the regulatory requirements.

The manufacturers who succeed under MDR are the ones who assess their clinical evidence needs early, make informed decisions about equivalence, and do not assume that a comparison table is sufficient proof.

The manufacturers who struggle are the ones who treat equivalence as a shortcut and discover too late that the route does not hold.

Your clinical evaluation strategy is not about minimizing work. It is about building a defensible file that meets the standard of evidence required under the regulation.

Choose the route that does that—not the one that looks easier on paper.

Peace,
Hatem
Clinical Evaluation Expert for Medical Devices
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