Issues from MDD to MDR in terms of mainly clinical evaluation and investigation

If you have already marked medical device according to the MDD, your certificate is valid until the expiry date on the certificate, but not longer than May 2024. 

Transition steps from MDD to MDR are as follows:

1) First, you need to check if the classification of your medical device changed. Go to Annex VIII – Classification rules - and check-in which rule your medical device falls now.
2) Take Annex I – General safety and performance requirements – and go through each requirement to check how is that requirement fulfilled for your medical device. Of course, not all requirements from this Annex I are applicable to all manufacturers. For example, if your medical device is not sterile, then requirements in section 11. Infection and microbiological cleanliness – are not applicable to you.
3) Then review your technical file and compare it with the documentation requirements from the Annex II Technical documentation and Annex III – Technical documentation on post-market surveillance. If you see that some documentation/information is missing, prepare those documents.
4) Review your QMS because there are some additional requirements regarding the QMS – MDR Article 10, paragraph 9, and Annex I.  For example, there is a requirement that within QMS there should be a strategy for regulatory compliance. Also, there is a necessity to put as part of the QMS Clinical evaluation process (Chapter 6) and Post-market surveillance system (Chapter 7).
5) Assign for the UDI number - The UDI, in general, is provided by an official designated entity. On the MDCG 2019-1 guiding principle of issuing entities rules on Basic UDI-DI, there are some requirements to follow.

For periodic audit that will be conducted after May 2021, you need to have prepared a Post-market surveillance system, vigilance system, and defined economic operators according to the MDR (for more details see Article 120).

Here you can find all the information:

EU MDR Article 10 – General obligations of manufacturers https://advisera.com/13485academy/mdr/general-obligations-of-manufacturers/
EU MDR Article 120 – Transitional provisions https://advisera.com/13485academy/mdr/transitional-provisions/
EU MDR Annex I - General safety and performance requirements https://advisera.com/13485academy/mdr/general-requirements/
EU MDR Annex II – Technical documentation https://advisera.com/13485academy/mdr/technical-documentation/
EU MDR Annex III – Technical documentation on post-market surveillance https://advisera.com/13485academy/mdr/technical-documentation-on-post-market-surveillance/
EU MDR Annex VIII – Classification rules https://advisera.com/13485academy/mdr/classification-rules/