When entering the market, orphan drugs are associated with substantial prices and a high degree of uncertainty regarding safety and effectiveness. This makes decision making about the reimbursement of these drugs a complex exercise. To advance on this, the Dutch government introduced a conditional reimbursement trajectory that requires a re-evaluation after four years. This article focuses on the origins, governance and outcomes of such a conditional reimbursement trajectory for orphan drugs. We find that the conditional reimbursement scheme is the result of years of discussion and returning public pressure about unequal access to expensive drugs. During the implementation of the scheme the actors involved went through a learning process about the regulation. Our analysis shows that previous collaborations or already existing organisational structures led to faster production of the required data on cost-effectiveness. However, cost-effectiveness evidence resulting from additional research seems to weigh less than political, judicial and ethical considerations in decision making on reimbursement of orphan drugs in the Netherlands.