Chapter 14: Regulatory Considerations and Strategies for Drug Repositioning

The 505(b)(2) pathway is used to obtain U.S. Food and Drug Administration approval of changes to existing drugs based in whole or in part on public data. This chapter identifies sources of public data and how it can be used in lieu of sponsor-conducted studies. Examples are presented to illustrate a broad range of improvements that can be made to an existing drug under 505(b)(2) as well as the scope of development requirements that can range from simple bioequivalence studies to more complete Phase 2/Phase 3 clinical programs. Patents and market exclusivity are discussed as a means to improve the return on investment needed to encourage the development of these important drug products.