Device modifications - Clinical sample size rationale

HelviReg

Involved In Discussions
Dear all,

We are developing a "new" medical device which shares the majority of its design with another of our products, currently CE marked and marketed. That new product will be intended for the same clinical indication.

We are now at the stage of defining the proper route for its clinical evaluation and we think that the demonstration of equivalence might be challenged by our NB. Altough the principle of operation and performance requirements are similar, the new product will achieve them with a different intensity of energy and will consequently induce a biological response slightly different. In a nutshell, almost equivalent but additional clinical data may be required to assess its conformity.

My question is, would it be possible to benefit somehow from these similarities to justify (based on stats or not) a clinical trial sample size lower than what is usually calculated with classical statistical methods ? The idea is to tell our NB: yes it is equivalent, and to be even more confident, here some "extra" clinical data.

The only content I've found related to that is the use of bayesian statistics which seems far from obvious and quite disruptive.

Thank you for your help,

Louis L.-
 
...the principle of operation and performance requirements are similar, the new product will achieve them with a different intensity of energy and will consequently induce a biological response slightly different.

Are you introducing a new clinical risk? It seems like you are. Can you derive the risk-benefit profile of the new device using the previous device's clinical data?
 

HelviReg

Involved In Discussions
Thanks for your reply.

No new clinical risks, but the current ones from the previous product are applicable. Therefore, the design mitigations have been reviewed and adapted to be implemented on the new product. Pre-clinical evaluations have been conducted to verify these mitigations.

The different pre-clinical results have highlighted some expected differencies between both products. Although we could argue and justify that these differencies do not raise raise new questions of safety and effectiveness, we think that adding new clinical performance data would streamline the review.
 

dgrainger

Trusted Information Resource
the new product will achieve them with a different intensity of energy and will consequently induce a biological response slightly different.

You are saying that the Technical and Biological characteristics are different - It isn't equivalent unless....

"The characteristics listed in the first paragraph shall be similar to the extent that there would be no clinically
significant difference in the safety and clinical performance of the device. Considerations of equivalence shall be
based on proper scientific justification. It shall be clearly demonstrated that manufacturers have sufficient levels of
access to the data relating to devices with which they are claiming equivalence in order to justify their claims of
equivalence."
 
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