Objective: We evaluated the efficacy and safety of amifampridine phosphate (Firdapse®) for symptomatic treatment in Lambert-Eaton myasthenic syndrome (LEMS). Methods: Phase 3, randomized, double-blind, study. Patients were treated initially with amifampridine phosphate for 7-91 days, followed by randomization to continue amifampridine phosphate for 14 days or placebo (7-day taper, 7-day placebo). The primary efficacy endpoints were changes from baseline at day 14 in Quantitative Myasthenia Gravis and Subject Global Impression scores. Results: The coprimary efficacy end points and 1 of the secondary efficacy end points were met, showing a significant benefit of aminfampridine phosphate over placebo at Day 14. All 5 primary, secondary, and tertiary endpoints achieved statistical significance at Day 8. Amifampridine phosphate was well tolerated; the most common adverse events were oral and digital paresthesias, nausea, and headache. Conclusions: This study provides Class I evidence of efficacy of amifampridine phosphate as a symptomatic treatment for LEMS.
ASJC Scopus subject areas
- Clinical Neurology
- Cellular and Molecular Neuroscience
- Physiology (medical)