FDA approves first treatment for Lambert-Eaton myasthenic syndrome

FDA has approved amifampridine (Firdapse—Catalyst Pharmaceuticals) tablets for the treatment of Lambert-Eaton myasthenic syndrome (LEMS) in adults. LEMS is a rare autoimmune disorder that affects the connection between nerves and muscles and causes weakness and other symptoms in affected patients.

FDA has approved amifampridine (Firdapse—Catalyst Pharmaceuticals) tablets for the treatment of Lambert-Eaton myasthenic syndrome (LEMS) in adults. LEMS is a rare autoimmune disorder that affects the connection between nerves and muscles and causes weakness and other symptoms in affected patients. This is the first FDA approval of a treatment for LEMS. "There has been a long-standing need for a treatment for this rare disorder," said Billy Dunn, MD, director of the Division of Neurology Products in FDA's Center for Drug Evaluation and Research. "Patients with LEMS have significant weakness and fatigue that can often cause great difficulties with daily activities." The efficacy of amifampridine was studied in two clinical trials that together included 64 adult patients who received amifampridine or placebo. The studies measured the Quantitative Myasthenia Gravis score (a 13-item physician-rated categorical scale assessing muscle weakness) and the Subject Global Impression (a seven-point scale on which patients rated their overall impression of the effects of the study treatment on their physical well-being). For both measures, the patients receiving amifampridine experienced a greater benefit than those on placebo. The most common adverse events experienced by patients in the clinical trials were burning or prickling sensation (paresthesia), upper respiratory tract infection, abdominal pain, nausea, diarrhea, headache, elevated liver enzymes, back pain, hypertension and muscle spasms. Seizures have been observed in patients without a history of seizures.