Patent Expiration

How It Works

Drug patents typically last 20 years from the filing date, but the effective market exclusivity period is shorter because patents are filed early in development, years before FDA approval. Most brand-name drugs have 8-15 years of effective patent life after launch. Manufacturers often employ strategies to extend patent protection: filing additional patents on formulations, delivery methods, or manufacturing processes (called "evergreening"), or making minor modifications to create new patentable versions. Patent expiration is the single most important event in a drug's lifecycle — generic entry typically reduces prices by 80-95% within a few years.

Related Terms

• Generic Drug — A medication that contains the same active ingredient, dosage, and form as a brand-name drug, approved after the original's patent expires — typically costing 80-95% less.
• Patent Cliff — A sharp drop in a drug's revenue when its patent expires and generic competitors enter the market, often cutting prices by 80% or more.
• Evergreening — Strategies drug manufacturers use to extend patent protection beyond the original expiration — including new formulations, delivery methods, or minor modifications.
• Exclusivity Period — A period of market protection granted by the FDA (separate from patents) during which generic competitors cannot be approved — even if no patent exists.