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

Officials with the FDA have approved amifampridine (Ruzurgi, Jacobus) tablets, the first treatment for children with the rare autoimmune disorder Lambert-Eaton myasthenic syndrome (LEMS), according to a press release.

In LEMS, the body’s immune system attacks the neuromuscular junction and disrupts the ability of nerve cells to send signals to muscle cells. The disorder causes weakness and other symptoms in affected patients. Although the prevalence of LEMS in children is not known, the overall prevalence is estimated to be 3 per million individuals worldwide, according to the FDA.

With this approval, amifampridine is the first treatment approved specifically for pediatric patients 6 to 17 years of age.

The approval is based on data from 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 children aged 6 to 17 years.

The study included 32 patients administered amifampridine for at least 3 months prior to initiating the trial and compared patients who continued on the treatment with those who switched to a placebo. According to the data, patients who continued on amifampridine experienced less impairment than those on placebo. The trial evaluated efficacy based on the degree of change in a test that assessed the time it took patients to rise from a chair, walk 3 meters, and return to the chair for 3 consecutive laps without pause. The trial also conducted a self-assessment scale for LEMS-related weakness that measured the feeling of weakening or strengthening.

Overall, the most common reported adverse effects experienced by both pediatric and adult patients taking amifampridine were burning or prickling sensation, abdominal pain, indigestion, dizziness, and nausea. Seizures have also been observed in patients with a history of seizures.

“We continue to be committed to facilitating the development and approval of treatments for rare diseases, particularly those in children,” Billy Dunn, MD, director of the Division of Neurology Products in the FDA’s Center for Drug Evaluation and Research, said in a statement. “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.”

The only other treatment for LEMS is only approved for use in adults, according to the FDA.

Reference

FDA approves first treatment for children with Lambert-Eaton myasthenic syndrome, a rare autoimmune disorder [news release]. FDA. https://bit.ly/2H66B8X. Accessed May 7, 2019.