Custom-made devices and clinical evaluation – what still applies

Written by HATEM RABEH, MD, MSc Ing

Your Clinical Evaluation Expert And Partner

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This scenario plays out regularly. The exemption from conformity assessment does not mean exemption from clinical evidence. Yet many manufacturers treat custom-made devices as though they exist outside the clinical evaluation framework entirely.

They do not.

The confusion stems from a misreading of the regulation. Article 52(8) exempts custom-made devices from conformity assessment procedures under Annex IX to XI. But the requirement to demonstrate safety and performance through clinical evidence remains. And so does the need for clinical evaluation, even if the format and depth differ.

Let me explain what still applies, where the boundaries are, and how to approach this correctly.

What Article 52(8) actually exempts

Article 52(8) states clearly: custom-made devices are exempt from the conformity assessment procedures set out in Annexes IX, X, and XI. This means no involvement of a Notified Body for certification. No technical file submitted for review in the traditional sense. No CE marking.

But the device still falls under the general safety and performance requirements of Annex I. And Annex I, Section 1, requires that devices achieve their intended performance and that risks are reduced to an acceptable level. Clinical evaluation is the tool that demonstrates this.

The exemption is procedural, not substantive.

Manufacturers assume that because they do not submit a full technical file, they do not need a clinical evaluation. This is incorrect. The regulatory logic remains: you must demonstrate that your device is safe and performs as intended. Clinical data is how you do that.

So what does change?

The scope and depth of clinical evaluation for custom-made devices

The clinical evaluation for a custom-made device is not identical to one for a mass-produced Class III device undergoing full Notified Body review. The scope adjusts to the nature of the device and the regulatory pathway.

But the core structure remains.

You still need to define the intended purpose clearly. You still need to identify clinical claims. You still need to establish a state of the art. You still need to demonstrate equivalence or generate clinical data if equivalence cannot be shown. And you still need to assess the benefit-risk profile.

The difference is in the depth of literature analysis, the formality of the appraisal, and the extent of documentation. For a custom-made device produced in limited quantity for a specific patient, you may rely more heavily on well-established equivalence to devices already on the market. The literature review may focus on key claims rather than exhaustive SOTA coverage. The clinical data may be observational rather than interventional.

But the reasoning must still be there.

I have reviewed files where manufacturers list the custom-made device, describe its design, and then stop. No equivalence claim. No clinical data. No explanation of how safety and performance were established. The justification: it is custom-made, so clinical evaluation does not apply.

This does not hold up.

When an incident occurs, the first question from the competent authority will be: how did you establish that this device was safe for this patient? If you have no documented clinical evaluation, you have no answer.

What you must document

Even for custom-made devices, you need a documented evaluation that addresses the following:

Intended purpose and claims. Be specific. What is the device meant to do for this patient? What performance is expected?

Equivalence or clinical data. If you claim equivalence to an existing device, document the technical and biological comparison. If no equivalent exists, provide clinical data supporting the design choices.

Benefit-risk assessment. What are the known risks? What are the expected benefits? Why is the benefit-risk profile acceptable for this specific use?

State of the art reference. Even a simplified one. Show that you understand what similar devices exist, how they perform, and where your device sits within that landscape.

The format may be shorter. The literature search may be targeted. But the logic must be complete.

Now, a question that comes up often: what about post-market surveillance?

PMCF and post-market obligations

Post-market clinical follow-up is where the ambiguity increases. The MDR does not explicitly require a PMCF plan for custom-made devices. Article 61 requires manufacturers to establish a PMCF system for implantable and Class III devices, but the regulation does not clarify how this applies when the device is custom-made and patient-specific.

The practical answer: some level of follow-up is expected, but the formality and documentation differ.

For a custom-made implant, you should document the patient outcome. This is not a full PMCF study. But it is clinical follow-up. You should know whether the device performed as intended, whether complications occurred, and whether the benefit-risk profile held.

This information feeds into your PMS system and your next clinical evaluation if you produce similar devices in the future.

I have seen manufacturers who produce custom-made devices regularly but treat each device as isolated. No tracking of outcomes. No aggregation of clinical data. When they eventually apply for certification of a similar mass-produced device, they have no clinical evidence base to draw from.

This is a missed opportunity.

Even without a formal PMCF plan, documenting outcomes allows you to build a body of evidence that supports future devices. It also demonstrates to regulators that you take safety seriously.

How competent authorities interpret the requirement

Competent authorities vary in how strictly they enforce clinical evaluation for custom-made devices. Some request full clinical evaluation reports during audits or incident investigations. Others focus on benefit-risk justification and equivalence documentation.

But the trend is clear: the expectation is increasing.

As the MDR matures, competent authorities are focusing more on the substance of clinical evidence, not just procedural compliance. A custom-made device exemption does not mean a free pass. If the device poses risk, if it is implantable, if it is used in a critical application, the authority will ask for clinical justification.

The safest approach is to document a streamlined but complete clinical evaluation. Tailor the depth to the device, but cover the essentials. This protects you in case of an incident, an audit, or a future submission for a related device.

Practical approach for manufacturers

If you manufacture custom-made devices, establish a template for clinical evaluation that can be adapted per device. The template should include:

– Intended purpose and patient-specific indication
– Equivalence claim with technical comparison, or clinical data if no equivalent exists
– Key literature or clinical references supporting design choices
– Benefit-risk assessment specific to the patient and application
– Any follow-up plan or outcome documentation

This does not need to be a 100-page CER. But it needs to be a reasoned document that someone reviewing the file can follow.

For recurring custom-made device types, aggregate the clinical data over time. This builds your evidence base and prepares you for potential future certification of a standardized version.

And if you are uncertain whether clinical evaluation applies to your specific device, ask yourself this: if an incident occurred, could you demonstrate that you had a rational basis for believing the device was safe and effective?

If the answer is no, you need a clinical evaluation.

Final reflection

Custom-made devices sit at an interesting intersection in the MDR. They are exempt from some procedural requirements, but not from the fundamental obligation to demonstrate safety and performance. The clinical evaluation requirement adjusts in scope, but it does not disappear.

Many manufacturers underestimate this. They assume the exemption is broader than it is. The result is incomplete documentation, undefended claims, and vulnerability during audits or investigations.

The manufacturers who get this right treat the clinical evaluation as a core part of device development, regardless of the regulatory pathway. They document the reasoning. They track outcomes. They build evidence over time.

And when the question comes – how do you know this device was safe? – they have an answer.

The exemption from conformity assessment is not an exemption from thinking.

Peace,
Hatem
Clinical Evaluation Expert for Medical Devices
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