FDA Approves Catalyst’s LEMS Drug

November 29, 2018

Rare Daily Staff

The U.S. Food and Drug Administration today said it approval Catalyst Pharmaceuticals’ Firdapse, the first treatment for the treatment of adults with Lambert-Eaton myasthenic syndrome (LEMS), a rare autoimmune disorder.

In people with LEMS, the body’s own immune system attacks the connection between nerves and muscles and disrupts the ability of nerve cells to send signals to muscle cells. LEMS may be associated with other autoimmune diseases, but more commonly occurs in patients with cancer such as small cell lung cancer, where its onset precedes or coincides with the diagnosis of cancer.

Firdapse enhances neuromuscular transmission of signals providing for improved muscle function.

“The FDA’s approval of Firdapse is a potentially transformative milestone in the lives of patients in the U.S. suffering with LEMS, as it now gives adult LEMS patients access to a new first-in-class-therapy,” said Patrick McEnany, chairman and CEO of Catalyst Pharmaceuticals. “The approval of Firdapse is a crowning achievement for our company and an important step forward in our transition into a premier neurological rare disease company.

The efficacy of Firdapse was studied in two clinical trials that together included 64 adult patients who received Firdapse or placebo. The studies measured the Quantitative Myasthenia Gravis score (a 13-item physician-rated categorical scale assessing muscle weakness) and the Subject Global Impression (a seven-point scale on which patients rated their overall impression of the effects of the study treatment on their physical well-being). For both measures, the patients receiving Firdapse experienced a greater benefit than those on placebo.

The most common side effects experienced by patients in the clinical trials were burning or prickling sensation, upper respiratory tract infection, abdominal pain, nausea, diarrhea, headache, elevated liver enzymes, back pain, hypertension and muscle spasms. Seizures have been observed in patients without a history of seizures.

Firdapse won European approval at the end of 2009 and has been available in Europe since April 2010. Catalyst, which licensed the drug in the United States from BioMarin, first sought U.S. approval in 2014, but the FDA said it would not approve the drug without an additional clinical trial. The FDA granted Firdapse Priority Review, Breakthrough Therapy, and Orphan Drug designations.

November 29, 2018
Photo: Patrick McEnany, chairman and CEO of Catalyst Pharmaceuticals

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