Spending for orphan indications among top-selling orphan drugs approved to treat common diseases
The Orphan Drug Act provides benefits to promote the development of rare disease treatments with limited sales potential. Policymakers have questioned whether this purpose is furthered in the case of “partial orphan drugs” approved to treat both rare and common diseases, as many of these drugs are top-sellers. In this study, we used national commercial claims data to estimate the proportion of spending on 15 top-selling partial orphan drugs that was for orphan indications in 2018. Of this spending, 21.4% was assigned to orphan indications, 70.7% to non-orphan indications, and 7.9% to neither orphan nor non-orphan indications (e.g., off-label use). Findings support growing concerns regarding the costs of granting orphan drug benefits to the sponsors of top-selling partial orphan drugs.