Conventional appraisal and reimbursement processes are being challenged by the increasing number of rare disease treatments (RDTs) with a small evidence base and often a high price. Processes to appraise RDTs vary across countries; some use standard processes, others have separate processes or adapted processes that explicitly deal with rare disease specificities. The objective of this study was to examine the impacts of different appraisal processes for two RDTs.

A case study analysis was conducted using countries with different forms of appraisal processes for RDTs for which public health technology assessment (HTA) reports were available. Two contrasting RDTs were chosen according to the criteria: rare versus ultra-rare treatment, affecting child versus adult, life-threatening versus disabling. Information from public HTA reports for each country's RDT appraisal was extracted into templates, allowing a systematic comparison of the appraisals across countries and identification of the impact of the different processes in practice.

Reports from Belgium, England, France, Germany, Italy, Netherlands, Norway, Scotland, Sweden, and the USA were selected for nusinersen (for spinal muscular atrophy) and voretigene neparvovec (for inherited retinal disorders). Countries with separate or adapted processes had more consistent approaches for managing RDT-related issues during appraisal, such as stakeholder involvement and criteria to address the specificities of RDTs, creating more transparency in decision-making.

Findings suggest that separate or adapted approaches for RDT appraisal may facilitate more structured, consistent decision-making and better management of RDT specificities.