Your Equivalence Claim Just Failed. Now What?
You submitted your clinical evaluation built on equivalence. The Notified Body reviewed your technical comparison and your clinical data analysis. Then came the deficiency letter. Your equivalence claim doesn’t hold. The device you thought was equivalent isn’t. Your path to CE marking just collapsed.
In This Article
This happens more often than most manufacturers expect. An equivalence strategy feels safe during development. The devices look similar. The intended use overlaps. The technical files share common ground.
Then the reviewers apply the actual requirements from Annex XIV and MDCG 2020-5. The gaps appear. The claim breaks. And now you’re facing a full clinical investigation requirement with timelines that weren’t in your project plan.
The question isn’t whether this can happen. The question is what you do next.
Why Equivalence Claims Fail
Most equivalence failures trace back to three patterns I see repeatedly in files.
First, the technical comparison was superficial. Manufacturers list similarities but skip the detailed analysis of differences. They focus on what matches and downplay what doesn’t. Reviewers do the opposite. They focus on differences and evaluate whether those differences affect clinical performance or safety.
When the technical comparison lacks depth, the equivalence argument collapses under scrutiny.
Second, the biological and clinical assessment wasn’t rigorous enough. The manufacturer declares equivalence based on materials and design, but the clinical data from the equivalent device doesn’t actually address the specific clinical questions for their device. The data exists, but it doesn’t demonstrate what needs to be demonstrated.
Third, the equivalent device itself has weak clinical evidence. This is common when equivalence is claimed to older devices that entered the market under previous directives. That device may have a CE mark, but its clinical evidence base doesn’t meet current MDR standards. Building your claim on weak evidence produces a weak claim.
Manufacturers often assume that if the equivalent device has a valid certificate, its clinical evidence is automatically sufficient for an equivalence claim. This assumption creates major gaps when reviewers evaluate whether that evidence actually supports your device under MDR requirements.
When any of these patterns appears, the Notified Body issues a deficiency. And that deficiency forces a decision.
The Immediate Decision Point
When your equivalence claim fails, you face two paths.
Path one: You attempt to recover the equivalence strategy by addressing the deficiencies. This works only if the core equivalence is actually valid and you can strengthen the comparison and the supporting data.
Path two: You abandon equivalence and build a standalone clinical evaluation based on your own clinical data. This means clinical investigation, literature for similar devices in the broader category, or a combination.
Most manufacturers try path one first. They don’t want to accept that equivalence is gone. They respond to the deficiency with more explanation, more technical detail, more justification.
Sometimes this works. If the equivalence was fundamentally sound but poorly documented, a stronger response can satisfy the reviewers.
But if the equivalence was never truly valid, the additional documentation just delays the inevitable. You spend weeks or months refining a strategy that will fail again in the next review cycle.
The critical skill here is recognizing which situation you’re in.
If your Notified Body questions fundamental aspects of technical equivalence or points to clinical differences that affect safety or performance, you’re likely in a non-recoverable equivalence situation. Trying to rescue it consumes resources better spent building the alternative path.
Recovering the Equivalence Strategy
If you decide to pursue recovery, the response must address the root cause the reviewers identified.
When the technical comparison was insufficient, you need to go deeper. This means revisiting every technical characteristic in Annex XIV. For each characteristic, you document not just similarity but why any differences don’t affect clinical safety or performance. You reference design controls, verification data, bench testing, and risk analysis.
The comparison becomes specific and traceable. Instead of stating that materials are similar, you show material specifications, biocompatibility data, and process controls. Instead of claiming functional equivalence, you demonstrate equivalence through performance testing that directly compares critical parameters.
When the biological and clinical assessment is the issue, you need to show how the literature and clinical data from the equivalent device actually answer your clinical questions. This often requires additional literature searches focused on the specific points of difference. It may require subgroup analyses of existing clinical data.
The goal is to demonstrate that despite any technical differences, the clinical performance and safety profile are equivalent. This requires clinical reasoning, not just technical description.
When the equivalent device has weak evidence, you have a harder problem. You might need to supplement that device’s evidence with your own clinical data or broader literature. At some point, this approach starts to look like a standalone evaluation anyway.
If you’re supplementing heavily, question whether equivalence is still the right strategy.
Pivoting to Standalone Clinical Evaluation
When equivalence can’t be recovered, you build a clinical evaluation without it.
This doesn’t mean you ignore existing knowledge. You still use literature from the same device category. You still reference clinical experience with similar technologies. But you’re not claiming your device is equivalent to one specific device. You’re demonstrating your device meets safety and performance requirements based on the totality of available evidence.
This requires identifying what clinical data you actually have. If you’ve done any clinical studies, usability studies, or post-market data collection during development, that data becomes central. If you haven’t, you need to plan clinical investigation.
The literature review expands. Instead of focusing on one equivalent device, you search for data across devices with similar intended use, similar technology, or similar clinical applications. The scope broadens, but the clinical questions remain specific to your device.
The clinical evaluation report structure changes. You’re no longer organizing around equivalence demonstration. You’re organizing around clinical safety and performance questions. Each question gets addressed through available data, with gaps clearly identified.
Where gaps exist, you need a plan. That might be a clinical investigation plan. It might be a PMCF plan with specific studies. It might be additional bench testing that provides indirect clinical evidence.
Manufacturers sometimes treat the pivot to standalone evaluation as just removing the equivalence section and keeping everything else. This fails because the entire evaluation logic was built around equivalence. The standalone evaluation needs different clinical questions, different data interpretation, and different gap analysis.
The Timeline Impact
Recovering from failed equivalence always affects timelines. The question is how much.
If you can strengthen the equivalence claim with existing data and better documentation, you might recover in one review cycle. That typically means 2-3 months of additional work and another review round.
If you need to collect additional data to support equivalence, the timeline extends to however long that data collection takes. This might be 6-12 months depending on what’s needed.
If you pivot to standalone evaluation and need clinical investigation, you’re looking at 12-24 months minimum. Clinical investigation requires ethics approval, patient recruitment, follow-up periods, data analysis, and reporting. Each of these steps takes time.
The strategic mistake is underestimating these timelines. Manufacturers often assume they can resolve equivalence issues quickly. They commit to response deadlines they can’t meet. They promise stakeholders timelines that aren’t realistic.
When the Notified Body questions your equivalence claim, build your timeline from the assumption that equivalence might fail completely. Plan for clinical investigation even while you attempt to recover the equivalence strategy. This way you’re prepared either way.
What This Means for Project Planning
The deeper lesson here is about project planning before you’re in a deficiency situation.
Equivalence is a strategy, not a certainty. When you plan a project around equivalence, you need a contingency plan for what happens if that equivalence doesn’t hold under regulatory review.
This means assessing equivalence early with the same rigor a Notified Body would apply. Before you commit to equivalence as your path, do the full technical comparison. Identify differences honestly. Evaluate whether you can justify those differences with available data.
If the justification requires assumptions or relies on weak evidence from the equivalent device, that’s a risk signal. You might pursue equivalence, but you should also plan for clinical investigation in parallel.
Some manufacturers do exactly this. They claim equivalence but initiate a clinical study during development. If equivalence holds, they have additional supporting data. If equivalence fails, they have the study already running.
This approach costs more upfront, but it eliminates the timeline shock when equivalence fails during review.
The manufacturers who recover fastest from failed equivalence are those who never fully committed to equivalence as their only path. They treated it as the preferred path but maintained readiness for the alternative.
Moving Forward
When your equivalence claim fails, the path forward depends on honest assessment of why it failed and what recovery actually requires.
If the failure was documentation quality, you can recover through better technical comparison and clinical justification. If the failure was fundamental non-equivalence, you need to pivot to standalone evaluation and likely clinical investigation.
The worst outcome is spending months trying to rescue an equivalence claim that was never valid while your timelines extend and your stakeholders lose confidence.
The better outcome is recognizing the situation quickly, choosing the right path, and executing that path with the rigor it requires.
Failed equivalence isn’t the end of the project. It’s a decision point. How you handle that decision determines whether you recover in months or years.
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), Annex XIV
– MDCG 2020-5 Clinical Evaluation – Equivalence
– MDCG 2020-6 Sufficient Clinical Evidence for Legacy Devices
