These programs, ushered in through pieces of legislation such as the 1992 Prescription Drug User Fee Act (PDUFA) and the 2012 Food and Drug Administration Safety and Innovation Act (FDASIA), include:

Orphan Drug Act (1983): "Set up to encourage the development of drugs for rare diseases" (defined as diseases affecting fewer than 200,000 Americans)[1]
Fast Tracking (1988): Facilitates the development and expedites the review of "drugs to treat serious conditions and fill an unmet medical need"

Accelerated Approval (1992 and 2012): Allows for "earlier approval of drugs that treat serious conditions, and that fill an unmet medical need based on a surrogate endpoint" (defined as "a laboratory measurement, radiographic image, physical sign or other measure that is thought to predict clinical benefit, but is not itself a measure of clinical benefit")
Priority Review (1992): Signals the FDA's intention to "take action on an application within 6 months"