Class IIb covers high-risk devices: ventilators, defibrillators, infusion pumps, non-articular orthopaedic implants, active devices for interventional radiology. The notified body’s review is more in-depth than for Class IIa. Certain points in the documentation concentrate the bulk of requests for additional information.
Blocking point 1: an insufficiently substantiated clinical evaluation
This is the point that blocks most often, and earliest in the assessment. For Class IIb, the clinical data must be substantial. The route of demonstrating equivalence with a device from another manufacturer is in the vast majority of cases inaccessible (contractual access to the technical data required by Article 61.5). A literature review alone, without clinical data specific to the device or to comparable devices with guaranteed access to the data, is often insufficient.
This point sometimes forces manufacturers to undertake clinical studies they had not planned. It is better to anticipate it from the moment the documentation is compiled.
Blocking point 2: an incomplete demonstration of equivalence across the three dimensions
When the demonstration of equivalence is possible (an equivalent device belonging to the same manufacturer), notified bodies verify the three cumulative dimensions defined in Article 61.5. Technical equivalence (design, materials, physical properties), biological equivalence (materials in contact with the body), and clinical equivalence (same indication, same population, same clinical environment) must each be demonstrated in a specific and documented manner.
A table listing characteristics in two columns without an in-depth comparative analysis is not a demonstration of equivalence that meets MDR expectations.
Blocking point 3: insufficient software validation for active devices
For Class IIb devices incorporating safety software classified as B or C according to IEC 62304, the software validation must meet the requirements of the standard. Insufficient test documentation, the absence of software requirements traceability, or deficient configuration management generate precise requests for additional information.
Blocking point 4: a PMCF plan without an operational protocol
For Class IIb, the PMCF plan is examined with greater stringency than for Class IIa. A plan that proposes to gather data from users without specifying the collection method (registry, observational study, structured questionnaire), the protocol, the sites, the evaluation criteria and the timelines is systematically returned for additional information.
Blocking point 5: an insufficiently argued benefit/risk assessment for complex active devices
For complex active devices (ventilators, infusion pumps, interventional imaging devices), the benefit/risk assessment must demonstrate that the benefits outweigh all residual risks under real conditions of use. Multiple failure modes, interactions with other devices or medicinal products, and risks associated with reasonably foreseeable misuse must all be covered.