Orphan Drug

**Semantic type:** Pharmacologic Substance

**Definition:** A compound or product that demonstrates promise for the diagnosis and/or treatment of rare diseases and conditions that affect fewer than 200,000 people. The U.S. Orphan Drug Act (1983) encourages development of these therapeutics by tax breaks and a seven-year monopoly on drug sales. These incentives promote the development and manufacturing of such therapeutics, which otherwise might not be profitable because of the small potential market.