Catalyst’s new drug application receives ‘Refusal to File’ letter from FDA

In a setback on the road to market for a Coral Gables-based biopharmaceutical company, the publicly traded Catalyst Pharmaceuticals received a “Refusal to File” letter from the U.S. Food and Drug Administration. It was in response to Catalyst’s New Drug Application for Firdapse, its drug for the symptomatic treatment of two rare disorders, Lambert Eaton myasthenic syndrome (LEMS) and congenital myasthenic syndromes (CMS).

The “Refusal to File” letter states that after a preliminary review, the FDA has found that the application was not sufficiently complete, and requests additional supporting information, Catalyst said in its news release. The letter does not provide comment on the acceptability of the submitted clinical data, and no judgment is made in the letter on the efficacy or safety of Firdapse, Catalyst said. Catalyst said it plans to request a meeting with the FDA to discuss the FDA’s comments on Catalyst’s NDA submission and to hopefully reach an understanding as to what will be required for the Firdapse NDA to be filed by FDA for review. The company submitted its application to the FDA in December 2015.

“We expect to work closely with the FDA over the coming weeks in an effort to resolve the open issues and to define a path forward for a successful resubmission of our application at the earliest point in time,” said Patrick J. McEnany, chairman and CEO of Catalyst, in a statement. “We remain focused on delivering on our promise to transform the way people living with LEMS and CMS are provided access to a safe and effective, FDA approved therapy.”

Catalyst has previously received Orphan Drug Designation for Firdapse to treat LEMS and CMS, and Breakthrough Therapy Designation for Firdapse to treat LEMS, which potentially can speed the approval process. Catalyst has an Expanded Access Program that provides Firdapse at no cost to patients who meet the enrollment criteria.

LEMS is a rare, debilitating and sometimes life-threatening autoimmune, neuromuscular disorder, characterized primarily by progressive muscle weakness of the limbs. Catalyst estimates that there are 3,000 LEMS patients in the United States. CMS, with an estimated 1,500 patients in the U.S., is a rare neuromuscular disorder characterized by fatigable weakness of skeletal muscles with onset at or shortly after birth or early childhood.

Catalyst stock fell 37.3 percent Thursday to close at $1.16. Catalyst’s path to FDA approval was chronicled in a Business Monday article in July.