Abstract

Challenges persist and specific policies, legislation, and process adaptations for orphan drugs are continuously being implemented. These have focused on improving the attractiveness of rare disease innovation via different types of regulatory incentives⁴ or adapting pricing and reimbursement frameworks and processes to help manage the challenges of limited evidence available at time of launch and high cost of these medicines.⁵ Examples of these adaptations include increasing willingness-to-pay thresholds, being more flexible about the level of evidence required to demonstrate effectiveness or cost-effectiveness, accepting broader elements of value, allowing greater clinical and patient input to decision making, and having bespoke rare disease appraisal committees. Few initiatives, however, have focused on new approaches to generating and evaluating clinical or cost-effectiveness evidence. The motivation for this themed issue was that we wanted to revisit the question of whether rarity should be treated differently, focusing on what has changed, what may have been incorrect/more debatable in the past and what may have not been addressed in previous work.