Why Your Equivalence Claim Fails Before Review Even Starts
I see the same pattern in every second clinical evaluation report that lands on my desk. The manufacturer claims equivalence to a predicate device. The documentation looks complete. But the foundation was never there. By the time the Notified Body opens the file, the outcome is already decided.
In This Article
Equivalence under MDR Article 61(5) and MDCG 2020-5 is not a documentation exercise. It is a technical demonstration that must be established before a single word is written in your clinical evaluation report. Yet most manufacturers approach it backward.
They select a device they believe is similar. They collect some technical data. They write a comparison table. Then they discover during review that the equivalence was never defensible in the first place.
This is not about missing documents. This is about misunderstanding what equivalence actually requires.
What MDCG 2020-5 Actually Demands
MDCG 2020-5 replaced the older MEDDEV 2.7/1 Rev 4 guidance and fundamentally changed how equivalence must be demonstrated under MDR. The requirements are not suggestions. They are the minimum threshold that every Notified Body will enforce.
The guidance defines equivalence through three dimensions: clinical, technical, and biological. All three must be met. Not partially. Not mostly. Completely.
But here is where teams go wrong from the start.
Manufacturers assume that similar intended use equals equivalence. They focus on what the device does rather than how it achieves that outcome. When the Notified Body asks for technical and biological characterization data, the manufacturer realizes they never validated whether the devices truly operate through the same mechanism.
Equivalence is not about similar outcomes. It is about identical mechanisms of action achieving those outcomes through comparable technical and biological means.
The Three Pillars You Cannot Compromise
Clinical Equivalence
Clinical equivalence means the devices have the same clinical condition, patient population, intended use, and indication for use. This sounds straightforward until you examine real cases.
A surgical stapler for gastrointestinal anastomosis and a surgical stapler for thoracic procedures may appear similar. Same technology. Same mechanism. But if the tissue characteristics differ, if the clinical setting differs, if the operator skill requirements differ, then clinical equivalence cannot be claimed.
I review cases where manufacturers argue that “both devices are used in surgery” as if that establishes clinical equivalence. It does not. The clinical context must be identical, not adjacent.
Technical Equivalence
This is where most equivalence claims collapse under scrutiny.
Technical equivalence requires that the devices use the same materials, have the same design characteristics, and achieve their intended performance through the same mechanism of action. MDCG 2020-5 is explicit: differences in technical characteristics must not adversely affect safety and performance.
But what does that mean in practice?
It means you must characterize every material, every design feature, every performance parameter. You must demonstrate that any differences either do not exist or do not create new risks or reduce effectiveness.
Technical equivalence is not proven by listing similarities. It is proven by systematically addressing every difference and demonstrating through technical documentation and testing that those differences do not compromise safety or performance.
When I see a technical comparison table with entries like “similar material” or “comparable design,” I know the manufacturer has not done the work. Similar is not equivalent. Comparable is not equivalent. You need specifications, testing data, and engineering documentation that proves identity or irrelevance of differences.
Biological Equivalence
Biological equivalence addresses biocompatibility and the nature of body contact. This is where ISO 10993 testing becomes critical.
If your device and the predicate device use different materials or have different types of tissue contact, you cannot simply reference the predicate’s biocompatibility data. You must generate your own.
Yet I see manufacturers claim biological equivalence based on material class alone. “Both devices use silicone.” But which grade of silicone? What additives? What surface treatment? What duration and type of contact?
The MDR and MDCG 2020-5 require that biological evaluation follows ISO 10993-1. If the devices differ in materials or contact, the biological equivalence claim fails unless you conduct your own biocompatibility testing.
Why Equivalence Documentation Fails Review
When a Notified Body rejects an equivalence claim, it is rarely because of poor writing. It is because the technical foundation was never established.
Here is what I observe repeatedly.
The predicate device was never validated as appropriate. The manufacturer selected a device that seemed similar but never confirmed that the predicate itself has sufficient clinical data, is legally marketed under MDR, and is not subject to field safety corrective actions. MDCG 2020-5 requires this upfront validation. Most manufacturers skip it.
The comparison is superficial. A table listing intended use, materials, and design features is not a demonstration of equivalence. It is a summary. The demonstration happens in the detailed technical files, test reports, risk analyses, and biocompatibility evaluations that prove identity or irrelevance of differences.
Differences are acknowledged but not addressed. The manufacturer notes that the devices differ in one design parameter or material composition, then proceeds as if equivalence still holds. Notified Bodies do not accept this. Every difference must be justified through technical data showing it does not affect safety or performance.
Manufacturers present equivalence as a conclusion rather than a demonstration. The clinical evaluation report states “Device X is equivalent to Device Y” without presenting the engineering analyses, test data, and risk assessments that would allow a reviewer to verify that conclusion independently.
The Notified Body is not there to trust your judgment. They are there to verify your evidence. If the evidence is not in the file, the equivalence claim will be rejected regardless of how confident you are in the similarity.
What Actually Works in Practice
Successful equivalence claims start with brutal honesty about whether equivalence is even possible.
Before you commit to an equivalence pathway, you must ask: Can I access complete technical, biological, and clinical data on the predicate device? If the predicate is from another manufacturer and you do not have a data-sharing agreement, the answer is no. You cannot demonstrate equivalence without access to detailed technical files and test reports.
If you have access, the next step is systematic comparison.
Create a detailed technical comparison that goes beyond high-level categories. Specify materials by grade and supplier. Specify design dimensions and tolerances. Specify manufacturing processes. Then for every parameter, document whether the devices are identical or different.
For identical parameters, reference the supporting documentation. For different parameters, provide technical justification and test data showing the difference does not affect safety or performance.
This is not a summary. This is a technical dossier that allows an independent reviewer to verify every equivalence claim.
Equivalence is defensible when you can hand your technical comparison file to a Notified Body reviewer and they can independently verify every claim without needing to ask you for missing data or clarification. If that is not possible, your equivalence documentation is incomplete.
When Equivalence Is Not the Right Path
Not every device should pursue equivalence. In fact, most devices should not.
Equivalence is appropriate when the devices are truly identical in all meaningful ways and you have access to robust clinical data on the predicate. It is a pathway that reduces the clinical investigation burden, but only when the technical foundation is solid.
If your device introduces any novel feature, any material change, any modification to the mechanism of action, equivalence becomes difficult to defend. The Notified Body will focus on those differences, and unless you can prove with hard data that they are irrelevant, the equivalence claim will fail.
In those cases, generating your own clinical data is not a fallback. It is the appropriate pathway from the start.
I see manufacturers try to force equivalence because they want to avoid clinical investigations. But a failed equivalence claim costs more time and more money than conducting a clinical investigation would have. When the Notified Body rejects the equivalence and asks for clinical data anyway, you have lost months and gained nothing.
The Reality of Notified Body Expectations
Notified Bodies are not looking for reasons to reject your equivalence claim. But they are bound by MDCG 2020-5 and MDR Article 61(5). They cannot approve an equivalence claim that does not meet the technical requirements, regardless of how reasonable it seems.
What they expect is simple: complete, verifiable documentation that proves equivalence across all three dimensions.
If they ask for additional data, it is because the existing documentation does not allow them to verify your claims. The solution is not better explanations. The solution is more data.
In my experience, the manufacturers who succeed with equivalence are the ones who treat it as a technical validation exercise, not a documentation shortcut. They collect the data first. They verify equivalence through engineering analysis and testing. Only then do they write the clinical evaluation report.
The ones who fail are the ones who write the report first and try to find data afterward.
Moving Forward
If you are planning an equivalence claim, start by asking whether you have everything MDCG 2020-5 requires. Not whether you think you can argue for equivalence. Whether you can prove it.
If the answer is no, your path is clinical investigation. If the answer is yes, your next step is building the technical dossier that demonstrates equivalence independently of the clinical evaluation report.
Equivalence is not a narrative. It is a technical case built on data. When the data is there, the documentation writes itself. When the data is missing, no amount of writing will compensate.
That is the difference between equivalence claims that pass review and equivalence claims that collapse under the first question from the Notified Body.
Peace,
Hatem
Clinical Evaluation Expert for Medical Devices
Follow me for more insights and practical advice.
Frequently Asked Questions
What is a Clinical Evaluation Report (CER)?
A CER is a mandatory document under MDR 2017/745 that demonstrates the safety and performance of a medical device through systematic analysis of clinical data. It must be updated throughout the device lifecycle based on PMCF findings.
How often should the CER be updated?
The CER should be updated whenever significant new clinical data becomes available, after PMCF activities, when there are changes to the device or intended purpose, and at minimum during annual reviews as part of post-market surveillance.
What causes CER rejection by Notified Bodies?
Common reasons include inadequate equivalence demonstration, insufficient clinical data for claims, poorly structured SOTA analysis, missing gap analysis, and lack of clear benefit-risk determination. Structure and logical flow are as important as the data itself.
Which MDCG guidance documents are most relevant for clinical evaluation?
Key documents include MDCG 2020-5 (Equivalence), MDCG 2020-6 (Sufficient Clinical Evidence), MDCG 2020-13 (CEAR Template), MDCG 2020-7 (PMCF Plan), and MDCG 2020-8 (PMCF Evaluation Report).
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Peace, Hatem
Your Clinical Evaluation Partner
Follow me for more insights and practical advice.
– Regulation (EU) 2017/745 (MDR), Article 61(5)
– MDCG 2020-5: Clinical Evaluation – Equivalence
– ISO 10993-1: Biological evaluation of medical devices
