An FDA decision to revoke designation of a drug (or a biological product) as an orphan drug is a rare event. (Though it’s not as rare as revocation of orphan drug exclusivity, which has happened only once – see our previous post here). Until recently, we were aware of only three orphan drug designation revocations in the 30-plus year history of the Orphan Drug Act. That number more than doubled in April 2016 when FDA revoked four orphan drug designations for various drugs for the treatment of hypertension in pediatric patients.
