Refusal to File letter from FDA to Catalyst Pharma relating to Firdapse (amifampridine phosphate) as a treatment for Lambert Eaton myasthenic syndrome

Catalyst Pharmaceuticals announced that it has received a "Refusal to File" letter from the FDA regarding its New Drug Application (NDA) for Firdapse (amifampridine phosphate). Firdapse is Catalyst's investigational drug candidate for the symptomatic treatment of 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, which was submitted in December 2015, was not sufficiently complete, and requests additional supporting information. The letter does not provide comment on the acceptability of the submitted clinical data, and no judgment is made on the efficacy or safety of Firdapse. Catalyst plans to request a meeting with the FDA as soon as possible 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.

Comment: Firdapse was EU approved for Lambert-Eaton myasthenic syndrome in 2009 for BioMarin.