"the biosimilar principle" vs. "the biosimilarity principle"

Question

From an EMA guideline:

This guideline lays down the non-clinical and clinical requirements for monoclonal antibody-containing medicinal products claimed to be similar to another one already authorised, i.e. similar biological medicinal products (biosimilars). The studies described here should be planned with the intention to detect any potential differences between biosimilar and reference medicinal product and to determine the relevance of such differences, should they occur. A biosimilar mAb should be similar to the reference mAb in physicochemical and biological terms. Any observed relevant difference would have to be duly justified and could contradict the biosimilar principle.

Is it acceptable to write biosimilar principle? I think that "biosimilarity principle" is the correct form, and I use "biosimilarity principle" in my translations.

Answer 1

Correct usage is "the biosimilar principle". The principle refers to biosimilars, which were previously mentioned and defined as "similar biological medicinal products".

That is, it is a principle dealing with the objects known as biosimilars, and not a principle that deals with the property of biosimilarity. Use of the second form can mislead readers as a result.

Compare with this made-up example, in which modular principle and modularity principle are both used, but where substituting either form for the other would be wrong.

The weights should be created by including the central module forms (modulars). If the weights are instead created using the central mean forms, the procedure is unlikely to succeed, as the modular principle has been violated.

Those forms should be tested to make sure they meet the standards (consistency and modularity). If testing is not used, the weights may be inappropriate due to violating the consistency principle or the modularity principle.