Assessment of significant benefit for orphan medicinal products by European regulators may support subsequent relative effectiveness assessments by health technology assessment organizations.

To maintain orphan drug status at the time of market authorization, orphan medicinal products (OMPs) need to be assessed for all criteria, including significant benefit, by the Committee for Orphan Medicinal Products (COMP) of the European Medicines Agency (EMA). Subsequently, health technology assessment (HTA) organizations evaluate the same OMPs in their relative effectiveness assessments (REAs). This review investigates the similarities and differences between the two frameworks for six HTA organizations, including the European Network for HTA. We discuss differences between both assessment frameworks within five domains (clinical evidence used, patient population, intervention, comparators, and outcome measures) for all drugs. Five illustrative cases studies were selected for a qualitative review.