Assessing Equivalence for a Flexible Endoscope
This worked example illustrates how we would assess equivalence for a flexible endoscope. It does not describe a completed client project.
CHALLENGE
In this scenario, a manufacturer is preparing a clinical evaluation for a reusable flexible endoscope used to visualise and examine the upper gastrointestinal tract. The device has extensive verification and validation data, but limited device-specific clinical data.
An established endoscope with a similar design and intended purpose has published clinical evidence that could be relevant. The manufacturer needs to determine whether the devices meet the applicable equivalence criteria and whether that evidence could support its clinical evaluation.
SOLUTION
Technical Comparison
We would compare the devices’ design and principle of operation, dimensions, insertion and working-channel specifications, imaging and illumination technology, field of view, bending capability and critical performance specifications. The comparison would also cover how and where the devices are used.
For example, the proposed device might have a wider field of view or a different distal-tip diameter. We would examine engineering data, simulated-use testing and the clinical context to assess whether those differences could affect safety or clinical performance.
For a wider field of view, the assessment would consider image interpretation and device operation. For a difference in distal-tip diameter, it would consider insertion, anatomical access and tissue interaction. Any conclusion that a difference was not clinically significant would need supporting evidence.
Biological Comparison
We would identify the patient-contacting components, including the insertion tube and distal components, and compare their materials, anatomical contact, contact type and duration.
Acceptable biocompatibility data for both devices would not, on its own, establish biological equivalence. The assessment would address the requirement for the same materials or substances to contact the same human tissues or body fluids, alongside the applicable similarity criteria for contact conditions and release characteristics.
Any material or contact differences would need to be examined against those criteria. We would review the available material characterisation and biological safety evidence to determine whether a biological equivalence claim could be supported.
Clinical Comparison
We would assess whether the devices had the same clinical purpose, were used at the same site in the body and were intended for the same kind of user. We would also compare the patient populations in terms of characteristics relevant to safety and performance.
The assessment would consider whether device differences could affect visualisation, procedure completion or adverse events such as tissue trauma, perforation and bleeding.
Clinical Evidence Review
Separately, we would appraise the quantity, quality and relevance of the clinical evidence available for the established endoscope. This could include prospective and comparative studies, observational studies, case series and post-market clinical experience.
The review would give greater weight to higher-quality evidence and examine limitations such as retrospective designs, small study populations, incomplete reporting and differences from the intended patient population. Demonstrating equivalence would not, by itself, establish that the available clinical evidence was sufficient.
INTENDED OUTCOME
The manufacturer would receive a documented assessment explaining whether an equivalence claim was supported, which differences mattered and where evidence gaps remained.
If equivalence could be demonstrated, the clinical evidence review would identify which data from the established endoscope could contribute to the new device’s evaluation, with their limitations recorded.
The aim would be to give the manufacturer a reasoned basis for deciding how to use existing evidence and what further evidence was needed.
