Amifampridine phosphate (Firdapse(®)) is effective and safe in a phase 3 clinical trial in LEMS.

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).