Q&A RELATED TO THE ASSESSMENT OF SIMILARITY FOR ADVANCED THERAPY MEDICINAL PRODUCTS (“ATMPS”) IN THE CONTEXT OF THE ORPHAN LEGISLATION. (updated)

The concept of similarity in an ATMP setting has been updated by European Commission on April 13. The Q&A document has been revised with new questions and examples based on accumulated experience. In particular, these questions have been raised by developers of ATMPs regarding the application of the concept of “similar active substance” in ATMP setting:

1. What differences in the starting materials may be considered relevant to support a claim of non-similarity?
2. Can a difference in principal molecular structural features be considered relevant to support a claim of non-similarity?
3. What level of evidence should be provided to demonstrate that differences in the biological characteristics and/or biological activity are relevant for the intended therapeutic effect and/or safety attributes of the product?

_{April 29, 2021}