Amifampridine (Ruzurgi) has been approved for the treatment of Lambert-Eaton myasthenic syndrome (LEMS), a rare autoimmune neuromuscular disorder, in patients aged 6 to less than 17 years, according to a statement from the Food and Drug Administration.
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The approval is the first for a LEMS treatment specifically for pediatric patients.
“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,” Billy Dunn, MD, director of the Division of Neurology Products in the FDA’s Center for Drug Evaluation and Research, said in the statement.
The prevalence of LEMS in pediatric patients is not known, but the overall prevalence of LEMS is estimated to be three per million individuals worldwide, according to the FDA press release.
Use of amifampridine in patients 6 to less than 17 years of age is supported by pharmacokinetic data in adult patients, pharmacokinetic modeling and simulation to identify the dosing regimen in pediatric patients, and safety data from pediatric patients 6 to less than 17 years of age.
A randomized, double-blind, placebo-controlled withdrawal study enrolled 32 adult patients who had taken amifampridine for at least 3 months. The study compared patients continuing on amifampridine with patients switched to placebo. Effectiveness was measured by the degree of change in a test that assessed the time it took the patient to rise from a chair, walk three meters, and return to the chair for three consecutive laps without pause. The patients who continued on amifampridine experienced less impairment compared with those switched to placebo. Effectiveness was also measured with a self-assessment scale for LEMS-related weakness. The scores indicated greater perceived weakening in the patients switched to placebo.
The most common side effects among amifampridine users were paresthesia, abdominal pain, indigestion, dizziness, and nausea. Side effects reported in pediatric patients were similar to those seen in adult patients. Seizures have been observed in patients without a history of seizures. Signs of hypersensitivity reactions include rash, hives, itching, fever, swelling, or trouble breathing.
The FDA granted this application Priority Review and Fast Track designations. Amifampridine also received Orphan Drug designation, which provides incentives to assist and encourage the development of drugs for rare diseases.
The FDA granted the approval of amifampridine (Ruzurgi) to Jacobus Pharmaceutical Company.