Catalyst Pharmaceuticals, Inc. announced that the U.S. Food and Drug Administration (?FDA?) has approved its supplemental New Drug Application (?sNDA?) increasing the indicated maximum daily dose of FIRDAPSE® (amifampridine) for adults and pediatric patients weighing more than 45 kg from 80 mg to 100 mg for the treatment of Lambert-Eaton myasthenic syndrome (?LEMS?). The increased maximum daily dose offers healthcare providers and patients greater flexibility in treatment regimens for the management of LEMS. LEMS is a rare autoimmune disorder characterized by muscle weakness and fatigue. FIRDAPSE is a potassium channel blocker indicated for the treatment of LEMS in adults and pediatric patients six years of age and older and works by increasing the release of acetylcholine, a neurotransmitter, at the neuromuscular junction, which helps improve muscle function in people with LEMS. FIRDAPSE is currently the only U.S. approved treatment for LEMS and this approval broadens the approved dosing options for prescribers treating LEMS. Patients in the U.S. can access FIRDAPSE by prescription through their healthcare providers.