MDCG 2020-6: Clinical Evidence for Legacy Devices and WET Under EU MDR
Legacy devices do not get a lower clinical-evidence standard simply because they have a long market history. MDCG 2020-6 explains how manufacturers should determine whether existing clinical evidence is sufficient under the MDR, how well-established technology (WET) fits into that assessment, and when additional clinical data may still be needed.
MDCG 2020-6 at a Glance
Authority
MDCG guidance, non-legally binding
Published
April 2020
Current Status
Current MDCG guidance
Read Alongside
MDR Article 61 and Annex XIV; MDCG 2020-5; Commission Delegated Regulation (EU) 2026/1451
The Headline
MDCG 2020-6 addresses one of the most important questions facing manufacturers of legacy medical devices:
How much clinical evidence is enough to support MDR conformity when a device was already CE marked under the MDD or AIMDD?
Its answer is not that legacy devices automatically require new clinical investigations.
Nor is it that a long market history automatically establishes sufficient clinical evidence.
Instead, the manufacturer has to determine and justify the level of clinical evidence necessary for the particular device, critically evaluate the evidence that already exists and identify whether any remaining gaps require additional clinical data.
That assessment needs to consider the quality, quantity, relevance and scientific validity of the available evidence, together with the device’s characteristics, intended purpose, risks and state of the art.
For well-established technologies, a lower level of clinical evidence may sometimes be justifiable. But that conclusion has to arise from the characteristics of the technology and the actual evidence base, not simply from the age of the product.
What You Need to Know
MDCG 2020-6 specifically addresses legacy devices.
It defines these as devices previously CE marked under the MDD or AIMDD.
The MDR still requires sufficient clinical evidence.
Article 61 requires manufacturers to specify and justify the level of clinical evidence needed to demonstrate conformity, taking account of the device and its intended purpose.
There is no universal evidence threshold for every legacy device.
The required level of evidence is device-specific.
Well-established technology has identifiable characteristics.
MDCG 2020-6 describes WETs as technologies with relatively simple and stable designs, a well-known safety profile, well-known clinical performance and standard-of-care status, and a long history on the market. All of those characteristics matter.
WET does not mean “clinical evidence unnecessary”.
Even devices exempt from a clinical-investigation requirement still need sufficient clinical data and a compliant clinical evaluation.
Post-market experience can be highly valuable, but not every post-market data source automatically constitutes clinical data.
Complaints, vigilance information and other PMS outputs need to be understood according to their regulatory and evidential role.
Evidence may still need to be generated.
MDCG 2020-6 expressly recognises that even devices used for decades may need PMCF or other new clinical data if the existing evidence does not adequately demonstrate safety and clinical performance against the current state of the art.
Does this apply to your device?
MDCG 2020-6 is particularly relevant if your device:
was previously CE marked under the MDD or AIMDD;
is transitioning, or has transitioned, to the MDR;
relies heavily on historical clinical experience, literature or PMS data;
has limited manufacturer-sponsored clinical investigation data;
is being described as a well-established technology;
is Class III or implantable and you are assessing whether a clinical investigation is required;
has an evidence strategy inherited substantially from its MDD-era clinical evaluation; or
has been on the market for many years but the current clinical-evidence sufficiency has never been explicitly reassessed under MDR.
It is less directly relevant to a genuinely new device with no previous MDD/AIMDD CE-marking history, although many of the underlying principles concerning evidence quality and sufficiency remain useful.
Still assessing whether your legacy device has sufficient clinical evidence under the MDR?
A 30-minute Clinical Evaluation Discovery Call gives you an opportunity to discuss your existing evidence, identify potential gaps and understand whether your clinical evaluation strategy needs updating in light of MDCG 2020-6 and the latest regulatory changes.
What “sufficient clinical evidence” actually means
One of the most useful aspects of MDCG 2020-6 is that it discourages manufacturers from reducing evidence sufficiency to a simple count of studies.
The MDR’s concept of the level of clinical evidence encompasses the amount and quality of evidence needed to demonstrate safety, performance and acceptability of the benefit-risk profile.
MDCG 2020-6 makes clear that this includes factors such as quality, quantity, completeness and statistical validity.
The practical question is therefore not:
“How many clinical studies do we have?”
It is:
“Does the total evidence base provide scientifically valid support for the relevant safety, performance and benefit-risk conclusions for this device and intended purpose?”
That requires judgement.
A device with extensive high-quality, directly applicable evidence may require comparatively little additional data.
A different device with decades of market history but sparse, indirect or methodologically weak evidence may still have an important evidence gap.
The Appendix III hierarchy
MDCG 2020-6 includes a suggested hierarchy of clinical evidence in Appendix III.
It is useful, but it should not be interpreted as a table of fixed minimum evidence levels that automatically apply by device class.
Its purpose is to help manufacturers think about the relative strength of different evidence sources when determining whether the overall evidence is sufficient.
The MDR requires a device-specific justification, not compliance with a universal numerical or hierarchical threshold.
What does “well-established technology” mean?
MDCG 2020-6 identifies four common characteristics of well-established technologies.
They have:
relatively simple, common and stable designs with little evolution;
a well-known safety profile, with the generic device group not historically associated with safety concerns;
well-known clinical performance characteristics, with the generic device group forming part of standard care and little evolution in indications or the state of the art; and
a long history on the market.
A long market history is therefore only one part of the assessment.
Twenty years on the market does not by itself make a device a well-established technology.
A device that has undergone substantial design evolution, operates in a rapidly changing state of the art or has unresolved safety or performance uncertainty may not fit the concept even if earlier versions have existed for decades.
Conversely, MDCG 2020-6 also explains that the WET concept is not restricted to the device types specifically listed in Article 61(6)(b).
That creates an important distinction between the broader WET concept and the specific legal clinical-investigation exemption.
The three concepts manufacturers should not confuse
1. Legacy devices under Article 61(6)(a)
Article 61(6)(a) provides an exemption from the normal clinical-investigation requirement for certain implantable and Class III devices that were lawfully placed on the market or put into service under the MDD or AIMDD, subject to the relevant conditions.
This is a legacy-device provision.
It does not mean clinical evaluation is unnecessary.
2. Listed well-established technologies under Article 61(6)(b)
Article 61(6)(b) identifies categories of implantable and Class III devices for which the usual Article 61(4) clinical-investigation requirement does not apply where the clinical evaluation is based on sufficient clinical data and relevant product-specific common specifications are met where available.
These are specific legally listed categories.
And that list changed materially in 2026.
3. Article 61(10)
Article 61(10) is different.
It concerns circumstances in which demonstrating conformity with the General Safety and Performance Requirements based on clinical data is not considered appropriate.
That route requires justification based on factors including risk management, the interaction between the device and the human body, intended clinical performance and manufacturers’ claims.
It is not another name for WET, and manufacturers should not treat “established device”, “WET” and “Article 61(10)” as interchangeable regulatory positions.
What changed in 2026
This is the major update that a current article on MDCG 2020-6 needs to include.
Commission Delegated Regulation (EU) 2026/1451 expanded the list of implantable and Class III device types in Article 61(6)(b).
The Regulation was published on 29th June 2026 and entered into force on 19th July 2026.
The original list already included devices such as sutures, staples, dental fillings, dental braces, tooth crowns, screws, wedges, plates, wires, pins, clips and connectors.
The expanded list now includes many additional technologies, including examples such as:
dental implants and other orthodontic devices;
bone substitutes and bone fillers;
spinal posterior fixations;
nails and anchors;
guidewires and pressure wires;
pacing wires and leads;
endovascular embolisation coils and particles;
ventricular drains;
port catheters;
cannulas;
reusable surgical instruments;
suspensory fixations and cinches; and
internal defibrillation paddles.
The full amended list is substantially broader.
The Commission based that expansion on the same general WET characteristics described in MDCG 2020-6: stable designs, well-known safety and performance, standard-of-care use and a long history on the Union market.
But the practical significance needs to be stated carefully.
Being on the list removes a particular clinical-investigation obligation. It does not remove the clinical-evaluation obligation.
The Commission states this explicitly: manufacturers of those devices remain required to plan, conduct and document clinical evaluation in accordance with Article 61.
That is why sufficient clinical evidence remains central.
What it means commercially
For some manufacturers, the expanded Article 61(6)(b) list can materially change the clinical development strategy.
If a Class III or implantable device now falls squarely within a listed technology, an expensive prospective clinical investigation that might otherwise have been required by Article 61(4) may no longer be necessary.
That can have substantial implications for development cost, programme duration and certification planning.
But it would be a mistake to convert:
“clinical investigation may not be required”
into:
“clinical evidence requirements are now minimal”.
They are not.
The manufacturer still needs sufficient clinical data to support safety, performance and benefit-risk conclusions.
For an established device with a strong literature base, robust device-specific post-market evidence and a stable state of the art, that may be achievable from the evidence already available.
For another device, removal of the mandatory clinical-investigation requirement may simply change how an evidence gap is addressed rather than make the gap disappear.
That distinction should be understood before a clinical development budget or MDR programme is changed.
What it means for your clinical evaluation
A strong MDCG 2020-6 assessment starts by separating several questions.
Is the device actually a legacy device?
Confirm that the device itself was previously CE marked under the MDD or AIMDD.
Do not assume that a new device belongs to the legacy framework simply because similar technology existed under the Directives.
What clinical evidence do we actually have?
Map the available evidence rather than beginning with the desired regulatory conclusion.
That may include:
manufacturer-sponsored clinical investigations;
published clinical literature;
clinically relevant registry evidence;
PMCF data;
relevant PMS-derived clinical information;
data from equivalent devices where MDR equivalence can genuinely be demonstrated; and
other scientifically valid clinical data relevant to the device and intended purpose.
How strong is that evidence?
Assess its quality, relevance, scientific validity and completeness.
Evidence that is directly applicable to the device and intended purpose generally carries greater value than indirect evidence requiring extensive extrapolation.
What claims is the evidence being asked to support?
Evidence sufficiency is inseparable from intended purpose, indications, target populations, claimed clinical benefits and performance claims.
A device may have a substantial evidence base and still lack adequate support for a newly broadened indication or claim.
What remains uncertain?
Residual uncertainty should be visible.
If the existing evidence does not resolve a material question about clinical safety or performance, the manufacturer needs a strategy for closing that gap.
Depending on the circumstances, that might involve PMCF, additional observational evidence, a clinical investigation or changes to the intended purpose or claims.
Where Manufacturers Commonly Get this Wrong
“It has been on the market for twenty years”
Market history is valuable.
It can provide extensive information about actual device use, safety experience and performance.
But longevity is not a substitute for the remaining WET characteristics or for sufficient clinical evidence.
A long-established device can still have poorly documented clinical performance, outdated clinical benchmarks or evidence that does not support its present claims.
Treating WET as a regulatory shortcut
WET is not an automatic low-evidence route.\
It describes a technology whose characteristics may justify a different evidential position.
The rationale therefore needs to demonstrate why the technology actually exhibits the relevant characteristics rather than simply label it “well established”.
Confusing WET with Article 61(10)
These are not the same thing.
Using Article 61(10) because a device is old or apparently well established risks starting from the wrong legal provision entirely.
Treating Appendix III as a pass/fail evidence table
The suggested hierarchy is useful for evaluating the relative strength of evidence.
It does not replace the manufacturer’s obligation to specify and justify the level of clinical evidence necessary for the individual device.
Treating PMS as a substitute for clinical evidence
PMS and vigilance information can be highly relevant, particularly in demonstrating a long and stable safety history.
But not every PMS data source constitutes clinical data, and absence of complaints does not by itself demonstrate clinical performance or benefit.
Assuming the 2026 exemption eliminates PMCF
It does not.
If clinical uncertainty remains, PMCF may still be necessary to maintain or strengthen the clinical evidence base.
MDCG 2020-6 specifically recognises that even well-established devices may need new PMCF data where the existing evidence does not adequately demonstrate safety and performance against the evolving state of the art.
Priority Actions
If you manage a legacy-device portfolio, I would work through the following:
1. Confirm which devices genuinely fall within the MDCG 2020-6 legacy-device definition.
2. Check whether any Class III or implantable devices are now included in the expanded Article 61(6)(b) list introduced by Regulation (EU) 2026/1451.
3. Do not stop at the clinical-investigation question. For any device benefiting from an exemption, document how sufficient clinical evidence will still be demonstrated.
4. If you are using a WET rationale, test all four characteristics explicitly. Do not rely on market age alone.
5. Map the actual clinical evidence available for each device and intended purpose.
6. Assess its quality, relevance and scientific validity rather than simply its volume.
7. Reassess older equivalence arguments against the MDR and MDCG 2020-5.
8. Identify evidence gaps early and decide whether they require PMCF, additional clinical investigation, other clinical-data generation or narrowing of claims.
9. Check that the rationale in the CER matches the evidence strategy in the CEP and the ongoing PMS/PMCF programme.
SciMed Perspective
MDCG 2020-6 is most valuable when it is used as a challenge to the existing evidence strategy, rather than as a document from which to find a convenient exemption.
A manufacturer with twenty years of market history may have a very strong clinical-evidence position.
But the strength comes from what those twenty years have actually generated: clinically relevant data, a well-understood safety profile, stable clinical performance, mature state-of-the-art understanding and evidence that still supports the current intended purpose.
Conversely, an old device can have a surprisingly weak MDR evidence position if its history has never been converted into scientifically usable clinical evidence.
The 2026 expansion of Article 61(6)(b) makes that distinction even more important.
For many manufacturers, the question of whether a new clinical investigation is legally required has become easier.
The question of whether the existing clinical evidence is sufficient has not disappeared.
How SciMed Can Help
SciMed supports manufacturers in assessing and documenting clinical evidence for legacy devices under the MDR.
That can include:
reviewing whether the existing evidence base is sufficient for the current device and intended purpose;
assessing whether a WET rationale is supportable;
determining the implications of the expanded Article 61(6)(b) exemption list;
reviewing equivalence strategies under MDCG 2020-5;
identifying clinical evidence gaps;
aligning CEP, CER, PMS and PMCF strategy; and
developing a proportionate evidence-generation plan where gaps remain.
Where the current position is uncertain, SciMed’s Clinical Evaluation Gap Analysis provides a structured assessment before those issues emerge during notified body review.
Primary Sources & Related Guidance
Primary Guidance
MDCG 2020-6, Regulation (EU) 2017/745: Clinical evidence needed for medical devices previously CE marked under Directives 93/42/EEC or 90/385/EEC - A guide for manufacturers and notified bodies, April 2020.
Current Legal Framework
Regulation (EU) 2017/745, Article 61 and Annex XIV Part A.
2026 Legal Update
Commission Delegated Regulation (EU) 2026/1451, amending Article 61(6)(b) as regards implantable and Class III devices exempt from the obligation to perform clinical investigations. In force from 19th July 2026.
Related Guidance
MDCG 2020-5, Clinical Evaluation - Equivalence.
MDCG 2023-7, Guidance on exemptions from the requirement to perform clinical investigations and sufficient levels of access to data needed to justify claims of equivalence.
MEDDEV 2.7/1 Rev.4, Clinical Evaluation: A Guide for Manufacturers and Notified Bodies.
Need support with an equivalence or wider Clinical Evaluation issue?
Continue the Clinical Evaluation Source Series
This is the fourth article in SciMed’s Clinical Evaluation source series.
Related articles:
MDR Annex XIV: What It Requires for Clinical Evaluation and PMCF
The legal framework for planning, conducting and maintaining clinical evaluation.MEDDEV 2.7/1 Rev.4 Under EU MDR: What Still Matters and What Has Changed
How the legacy MEDDEV methodology should be used within the current MDR framework.MDCG 2020-5: How to Demonstrate Equivalence Under EU MDR
How technical, biological and clinical equivalence should be demonstrated and maintained.
