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505(b)(2) Applications: History, Science, and Experience*

In 1984, the 505(b)(2) application route for a New Drug Application was created by Congress to allow applicants to create innovative medicines using currently available products without performing a full complement of safety and efficacy studies. This article reviews the history of the approach, provides examples, and considers some of the scientific and technical challenges associated with documenting safety and efficacy relative to the proposed change. The approach does not appear to have been used extensively in the almost 18 years since it was created. The explanation for this is not fully apparent, but may relate to the limited exclusivity, usually three years, allowed for a 505(b)(2) application.