The use of clinical data of a "similar" medical device based on the principle of equivalence is highly problematic due to the need to demonstrate full equivalence in terms of technical, biological and clinical characteristics. For simple medical devices, usually of the low-risk class, it is even more difficult from a certain point of view.
In particular, the area of biological characteristics, i.e. so-called biocompatibility, makes proving equivalence a very complicated and expensive process for all manufacturers who want to use the procedure according to Article 61, paragraph 3 of Regulation 2017/745 ("MDR"). The situation is made all the more complicated by the fact that these are usually products with low added commercial value due to their "genericity". So what's the problem?
The MDR requires that an equivalent device uses the same materials or substances in contact with the same human tissues or body fluids with a similar type and duration of contact and a similar behavior of the substances in terms of release to the environment, including products of degradation and other released substances. Recall that the manufacturer usually has no chance to prove access to the data of an equivalent medical device within the scope of the requirements of MDCG 2023-7. The requirement for products of degradation and leachbles is specified by MDCG 2020-5 to include leachables, degradation products, residues from manufacturing, etc.
The first problem in this area is that manufacturers of simple medical devices, usually Class I, would have to carry out expensive physical and chemical characterizations of both their (understood) and the equivalent device. This is usually, due to the cost, practically unrealistic.
The second problem is that in the event of a detailed physical and chemical characterization of both devices, supported by appropriate tests, it will very likely turn out that the materials are not the same, e.g. due to differences in the production technologies used. If we follow MDCG 2020-5, we find that (copied in abbreviated form):
"processing, design and the use environment may introduce small changes even when the raw materials are the same"
and further: "processing can make materials more susceptible to degradation by changing properties of the material and/or by inducing different stresses",
"to estimate the type and quantity of leachables from the final device"
and further, for example: "also other constituents for example residuals from the manufacturing process or sterilization, any contaminations etc".
The implementation of the plan of demonstration of equivalence, according to the literal requirements of the MDR and the mentioned MDCG documents, leads to a disproportionate consumption of time and costs. For example, tests to detect leachables can cost as much as a ten thousand Euro for some products, and this does not even include the cost of an expert assessment of the result of the test. A key factor is also the lack of experts who are able to interpret the results in timely manner.
Our recent consultation at the State Institute for Drug Control (SUKL), which has the role of a competent authority for medical devices in the Czech Republic, provided us with a guide for the way out of this dead road. During this consultation, we discussed the above-mentioned issue with SÚKL experts and together we looked for a solution. SÚKL's position on the described problem is that the depth of the proof of equivalence in the field of biological characteristics should be limited to the same level of details as is necessary to assess compliance with the GSPR in the field of biocompatibility. For example: Let's imagine a simple medical device example where, due to the nature and length of contact of the device with the patient's body, the assessment of biocompatibility will be limited only to cytotoxicity, sensitization and skin irritation endpoints. In such a case, in order to proof the equivalence in the area of biological characteristics, it will be necessary to review and assess the equivalence in the area of physical and chemical characteristics as well as in the area of cytotoxicity, sensitization and skin irritation only.
This limitation of the level of necessary detail is certainly a great advantage for all manufacturers who want to go down this path of obtaining clinical data. The greatest benefit will certainly be for manufacturers of Class I devices. Let's hope that for higher risk classes, the view of notified bodies will be the same as that of Czech competent authority.
Author: Aleš Martinovský
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