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# FDA Approves Catalyst Firdapse for LEMS
- URL: https://www.fdaweb.com/fda-approves-catalyst-firdapse-for-lems/
- Published: 2018-11-30T12:00:00.000Z
- Updated: 2026-09-15T00:47:54.000Z
- Author: David McFarland
- Tags: Drugs, #legacy-id-D5142932

FDA has approved a Catalyst Pharmaceuticals NDA for Firdapse (amifampridine) 10 mg tablets for treating adults with Lambert-Eaton Myasthenic Syndrome (LEMS), a rare autoimmune disease that affects about 1 in 100,000 people in the U.S. The most common LEMS symptoms are proximal muscle weakness and fatigue. Symptoms can be life threatening when the weakness involves respiratory muscle, according to the company.

Approval was based on data from two Phase 3 studies where patients treated with Firdapse “experienced rapid, significant and sustained improvements in muscle function, and reduced weakness and fatigability compared to patients receiving placebo,” Catalyst says. Firdapse had previously received an Orphan Drug designation and a Breakthrough Therapy designation, as well as a priority review from FDA.