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What Is Considered a Significant Change Under EU MDR Article 120(3)?

The EU MDR imposes strict requirements on medical device companies marketing their products in Europe. Many device companies scrambled to renew existing CE certificates granted under the old Medical Devices Directive, allowing them to sell that device in Europe until those certificates expire or May 2024, whichever comes first.

Whatever the reason, companies need to be careful to make sure they do not make significant changes that would raise the ire of Notified Bodies and trigger a mandatory new EU MDR registration, or risk having to prematurely pull their product from the EU market. Let’s consider an example.

Suppose you renewed an existing MDD certificate but want to make changes to the device before it expires? Well, you have two options, neither of them appealing:


  1. Pull the device off the market while you pursue CE certification under the EU MDR
  2. Determine if the change is considered “significant” and, if it is not, secure a derogation (permission) from your Notified Body to make the change

A Strong Need to Define “Significant”

It is important to highlight that no issuing of new AIMDD/MDD certificates is allowed under Article 120(3c), point (b) MDR12 (see also section 4.1). Therefore, if the manufacturer wishes to make a ‘significant change in design or intended purpose’ within the meaning of Article 120(3c), point (b) MDR, the implementation of such a change would prevent the manufacturer from placing the device on the market under the AIMDD/MDD in accordance with that provision.

Here’s an excerpt from Article 120 of the MDR, which we have shortened for clarity:

“By way of derogation…a device with a certificate that was issued in accordance with Directive 90/385/EEC or Directive 93/42/EEC…may only be placed on the market … provided there are no significant changes in the design and intended purpose.” 

Ok, this would seem to indicate that only changes to the device design and intended purpose count as “significant.” That’s not really true. (We’ll get to that in a minute.) After the EU MDR was published, various industry groups understood that manufacturers might, shall we say, apply liberal interpretations of the word “significant.” As such industry has been clamoring for official guidance that would add more specificity to Article 120. The Medical Device Coordination Group (MDCG) finally did so in releasing MDCG 2020-3 revision 1 changes. The main content of this document is contained in five decision trees focused on key areas of change:

Examples of Changes Outlined in MDCG 2020-3 That May Be Considered “Significant” Under Article 120(3)

Here are some (but not all) common examples of changes that may be considered significant according to the guidance. Please study the guidance and consult with your Notified Body as their opinion may differ from yours.


Chart A – Intended Purpose

  • Extension of the intended purpose, such as:
    • additional or new indications;
    •  additional or new clinical conditions.
  • New user or patient population, such as:
    • additional or new target population;
    • additional or new user (e.g. change from professional use to layman use)
  • New way of clinical application, such as:
    • additional or new applications (different stage or severity of disease);
    • additional or new anatomical site;
    • new delivery pathway or deployment method.

Chart B – Design or Performance Specification

  • Requires further clinical or usability data
  • New risks require control measures
  • Existing risks negatively affected
  • Change to built-in control mechanism
  • Change to operating principles, source of energy or alarms

Chart C – Software

  • New or major change to operating system or component
  • New/modified architecture/database structure
  • Change of algorithm (but not software bug fixes, security updates)
  • Required user input replaced by closed loop algorithm
  • New diagnostic or therapeutic features or new channel of interoperability
  • New user interface or presentation of data that impacts performance

Chart D – Materials

  • Change of material of human/animal origin, including addition of new materials
  • Change to material containing a medicinal substance, or the substance itself
  • Manufacturing or other change that may impact quality, safety or efficacy of a medicinal substance
  • Ingredient or material from new supplier does not meet existing specification

Chart E – Sterilization/Packaging

  • Change to terminal sterilization method
  • Design change that affects or changes sterility assurance
  • Packaging design change affects functionality, safety, stability or seal integrity
  • Shelf life change not validated by protocols approved by Notified Body

Again, this is not a complete list so be sure to download MDCG 2020-3 Rev.1


Changes to Your QMS Can Count as “Significant” as Well!

“Significant” changes are not limited to changes in design and intended purpose. While most of the guidance focuses on changes to the device, materials, or its intended purpose, those are not the only changes a Notified Body may see as significant enough to invalidate an MDD CE certificate. Section 9.6 of this document issued by the International Accreditation Forum (IAF) in 2022 discusses QMS changes that Notified Bodies may consider significant. They include:

  • Change in company ownership
  • Extension to manufacturing and/or design control
  • New facility or line modification/relocation
  • Significant modifications to special processes
  • Change in authority of the management representative
  • Postmarket surveillance and vigilance issues
  • Concerns about implementation or corrective actions


Here are some common examples of changes that could be deemed significant:

  • Making an insignificant design change to mitigate risks discovered during postmarket surveillance may constitute a significant change for that product.
  • Changing the floorplan of a manufacturing facility, especially for processes considered “special” or critical to the product. This could be considered a significant change, and it may require that the change be implemented in compliance with the regulations.
  • A manufacturer consolidates or centralizes a key system of their QMS (e.g., design control) across multiple sites.

Be Mindful of Changes and Their Impact

Manufacturers looking to extend the life of their MDD CE certification should always be mindful of the fact that Notified Body auditors will be examining their devices and processes through the lens of the EU MDR and ISO 13485:2016. Understanding which changes are allowable is critical before actually making them. When in doubt, talk to your Notified Body before considering any changes.

Want to Learn More?

We have two training classes that may interest you. This intensive training class on medical device design control gives you an in-depth look at how to properly structure your QMS processes and manage changes.  Our popular EU MDR auditor training class is also an excellent deep dive into all facets of 2017/745. Of course, our EU MDR consulting team remains at your service to answer questions about what is (and is not) a “significant” change.

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