Toxicologic Pathology Forum*: Opinion on Addressing Gaps in INHAND Terminology for Medical Devices-A Proposal to Add New Diagnostic Nomenclature.

Historically, safety and efficacy assessment of medical devices began and has continued as standards under the International Organization for Standardization (ISO) rather than under regulatory agency guidelines applied to developing other biomedical product classes. These parallel and unequal pathways have led to multiple and substantive differences in methods and endpoints to determine adverse biological responses among therapeutic classes. Toxicologic pathologists with medical device experience consider standardized nomenclature and diagnostic criteria for medical devices and device-containing combination products as a critical unmet need for nonclinical pathology evaluations. The International Harmonization of Nomenclature and Diagnostic Criteria for Lesions (INHAND) initiative has established globally accepted terminology for proliferative and nonproliferative lesions in various laboratory animal species. Experienced pathologists have identified that some existing INHAND terms for rodents and particularly nonrodents are already used or can be modified for use in medical device studies, but new terms for diagnostic features unique to medical device studies are needed to close gaps in existing INHAND nomenclature. The best approach to establishing appropriate INHAND terms for medical devices (and by extension, device-containing combination products) will be to develop and implement suitable terminology (modified and new, as warranted) to address unmet needs for this distinctive therapeutic class.