Market Exclusivity for Drugs with Multiple Orphan Approvals (1983–2017) and Associated Budget Impact in the US

The Orphan Drug Act extends exclusivity of branded drugs by 7 years for each rare disease approval. By extending market exclusivity, manufacturers can forestall generic competition. We determined the prevalence of drugs with multiple orphan approvals, the duration for which manufacturers are able to maintain exclusivity using this mechanism, and the budget impact of these additional exclusivity periods on US spending on orphan drugs. We analyzed...