The application of the principle of equivalence to the clinical evaluation of medical devices is particularly challenging due to the need to demonstrate full equivalence in technical, biological and clinical characteristics.
What's the issue? The MDR explicitly requires that the equivalent device uses the same materials or substances in contact with the same human tissues or body fluids for similar type and duration of contact and similar behaviour of the substances in terms of release into the environment, including breakdown products and other released substances. Recall that the manufacturer usually has no way to prove access to data of an equivalent device within the scope of the requirements of MDCG 2023-7. The requirement for breakdown products and other releases is specified by MDCG 2020-5 to include leachables, degradation products, etc. The fundamental problem is that manufacturers would have to perform costly physical and chemical characterization of both their (evaluated) and equivalent product. That is usually, due to the cost, practically unrealistic. For further details on this issue, we recommend referring to MDCG 2020-5. Proving equivalence, according to the literal requirements of the MDR and MDCG, leads to a disproportionate consumption of time and costs. For example, tests for detecting leachables can cost up to a quarter of a million crowns for some products, and that is without even the cost of an expert assessment of the result. The situation is even more complicated in the case of low added commercial value products due to their 'generic' nature, where the process has no chance of financial return.
A consultation with experts from the State Institute for Drug Control (SÚKL), during which we sought a solution, provided guidance on resolving the impasse. SÚKL’s position is that the equivalence investigation should be limited in the biological properties to the same level of detail required for assessing compliance with GSPR biocompatibility requirements.
Consider an example where biocompatibility assessment, due to the nature and duration of contact with the patient's body, focuses only on cytotoxicity, sensitisation and skin irritation. In such cases, equivalence in biological properties must also be evaluated in terms of physical and chemical properties, as well as in the area of cytotoxicity, sensitisation and skin irritation, to justify equivalence in the area of biological properties. This 'blurring' of details is a major advantage for manufacturers wishing to pursue this route of obtaining clinical data. It will certainly be of greatest benefit to manufacturers of Class I devices.
Author: Aleš Martinovský