OBJECTIVES: The Orphan Drug Act of 1983 provides branded drugs with extended exclusivity up to 7 years per approved rare disease indication. The Act may impact long-term availability of affordable alternatives if manufacturers apply for multiple approvals, thus preventing competition. Our objective was to determine the additional time that orphan drugs maintained market exclusivity through multiple indications, and estimate the budget impact of exclusivity extensions.

METHODS: We analyzed a retrospective cohort of FDA Orphan Drug Approvals (1983-2017). Average time of exclusivity gained per additional approval was calculated to determine whether certain drugs were gaining additional exclusivity with multiple approvals. Fixed effects regression analyzed extended duration of exclusivity per approval over time. Budget impact analysis measured the price difference between branded and generic alternatives, assuming a 75% drop in wholesale acquisition cost with exclusivity loss, for all drugs with 7+ additional years of exclusivity. These price differences were then applied across prevalences of each rare disease indication.

RESULTS: CONCLUSIONS: Manufacturers gain leverage from the Orphan Drug Act to maintain branded status longer, and may contribute to increasing drug costs. Limiting additional exclusivity periods for a drug could increase access and affordability, and motivate competition.