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# FDA, Catalyst Agree on Confirmatory Phase 3 Trial
- URL: https://www.fdaweb.com/fda-catalyst-agree-on-confirmatory-phase-3-trial/
- Published: 2016-06-16T12:00:00.000Z
- Updated: 2026-09-14T21:10:08.000Z
- Author: David McFarland
- Tags: Drugs, #legacy-id-D5135968

FDA and Catalyst Pharmaceuticals have reached agreement on a confirmatory Phase 3 study protocol for Firdapse (amifampridine phosphate), indicated for the symptomatic treatment of Lambert-Eaton myasthenic syndrome (LEMS). As part of the clinical protocol for the confirmatory study, Catalyst says it will initiate a small, single-center study with Firdapse during the second half of 2016\. The company says it will announce additional information about the study design and timelines for the study once they are finalized.

FDA recently told Catalyst that it will need positive results from an additional study to support an NDA submission. The agency also wants several additional short-term toxicology studies, according to the company. The drug has been given breakthrough therapy and orphan drug designations for its proposed LEMS indication and Catalyst is also seeking an indication for congenital myasthenic syndrome.