FDA Approves First Treatment for Children with Lambert-Eaton Myasthenic Syndrome

The Food and Drug Administration (FDA) has approved amifampridine (Ruzurgi; Jacobus Pharmaceutical Company, Princeton, NJ) for treating Lambert-Eaton myasthenic syndrome (LEMS) in patients age 6 to 17 years. 

This is the first FDA approval of a therapy specifically for pediatric patients with LEMS, a rare autoimmune neuromuscular junction disorder.   

Use of amifampridine in pediatric patients is supported by clinical studies in adults with LEMS, pharmacokinetic data in adult patients, pharmacokinetic modeling and simulation to identify the dosing regimen in pediatric patients, and safety data from pediatric patients. 

The effectiveness of amifampridine was established by a randomized, double-blind, placebo-controlled withdrawal study (NCT01377922) of 32 adult patients who took the drug for at least 3 months prior to entering the study. 

Effectiveness was measured by the change in the time it took patients to rise from a chair, walk 3 meters, and return to the chair 3 consecutive times without pause. The patients who took amifampridine experienced less impairment than those on placebo. 

“We continue to be committed to facilitating the development and approval of treatments for rare diseases, particularly those in children,” said Billy Dunn, MD, director of the Division of Neurology Products at the FDA Center for Drug Evaluation and Research. “This approval will provide a much-needed treatment option for pediatric patients with LEMS who have significant weakness and fatigue that can often cause great difficulties with daily activities.”