Gepirone is an antidepressant and anxiolytic drug of the azapirone group that was synthesized by Bristol-Myers Squibb in 1986 and has been under development for the treatment of depression but has yet to be marketed. It has been under development in the U.S. in an extended release form (referred to as gepirone ER), but despite completing phase III clinical trials and demonstrating efficacy, it has been rejected multiple times by the Food and Drug Administration (FDA) during the drug approval process. However, in March 2016, the FDA reversed course and ruled favorably on the efficacy of gepirone.