Rare Daily Staff

The U.S. Food and Drug Administration accepted Catalyst Pharmaceuticals’ application to market its Firdapse for the rare automimmune disease LEMS under a Priority Review.

Priority Review is granted by the FDA to drugs with the potential to address a serious condition and, if approved, would provide a significant improvement in safety or effectiveness of the treatment, prevention, or diagnosis of a serious condition.

The FDA has set a Prescription Drug User Fee Act action date of November 28, 2018.

LEMS, also known as Lambert-Eaton Myasthenic Syndrome, is most often characterized by muscle weakness of the limbs. The disease is caused by an autoimmune reaction where antibodies are formed against voltage gated potassium channels in the connection between nerves and the muscles they communicate with.

LEMS generally affects the extremities, especially the legs.  As the disease most affects the parts of limbs closest to the trunk, difficulties with climbing stairs or rising from a sitting position are commonly noted. Physical exercise and high temperatures tend to worsen the symptoms. Other symptoms occasionally seen include weakness of the muscles of the mouth, throat, and eyes. Individuals affected with LEMS also may have a disruption of the autonomic nervous system, including dry mouth, constipation, blurred vision, impaired sweating, and/or hypotension.

“Together with the previous grant of Breakthrough Therapy Designation, the Priority Review underscores the robust potential of Firdapse and the need for a safe and effective FDA-approved treatment for LEMS,” said Patrick McEnany, chairman and CEO of Catalyst.

The submission is supported by positive results from two Phase 3 studies.

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 Breakthrough Therapy designation in August 2013.

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

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