FDA Requires Additional Trials For Catalyst Pharmaceuticals’ Rare Disease Drug

Just two months after Catalyst Pharmaceuticals received a rarely-issued Refuse to File letter from the US Food and Drug Administration (FDA), the biotech has faced more hurdles with the regulatory agency. The FDA is now requiring that the company conduct more trials to test the safety of its rare disease drug candidate, Firdapse.

The drug is designated to treat a rare neuromuscular disease called Lambert-Eaton myasthenic syndrome (LEMS). The FDA previously gave Firdapse a breakthrough designation, and the drug has also been granted orphan drug status.

In one Phase III clinical trial of the drug involving 38 patients with LEMS, Firdapse met both of its primary endpoints of improving patient-reported and physician-rated symptoms of the disease. The treatment was significantly more effective than the placebo, while being safe and well-tolerated in most patients.

In February of this year, another late-stage trial conducted by Catalyst was labelled as “not sufficiently complete” by the FDA. As of Tuesday, the regulator is also requiring that the drugmaker submit positive results from an additional, well-controlled study along with their New Drug Application for Firdapse.

The FDA is reportedly open to discussing a study design that would satisfy this requirement, but they also want Catalyst to perform several more short-term toxicology studies of the drug. These new studies will not only be financially costly for the biotech, but will also delay the drug’s release on the market.

“While we are very disappointed by this delay, Catalyst and our employees remain committed to working with the FDA and bringing Firdapse to market for patients suffering with LEMS and congenital myasthenic syndromes (CMS),” said Patrick J, McEnany, CEO of Catalyst. “We are surprised with the FDA’s request for an additional clinical study for Firdapse, but are encouraged that the agency is open to an efficient, small short-term study design. We are currently in discussions with the FDA, and our clinical experts regarding the protocol and logistics for this confirmatory study.”

Along with LEMS and CMS, the drug is also being tested in patients with MuSK-Antibody Positive Myasthenia Gravis. “As always, we remain committed to LEMS and CMS patients with our continued research and our expanded access program, which continues to enroll new patients and provide Firdapse at no charge to eligible patients,” said McEnany.

The drug has been available in Europe since 2009, where it is marketed by BioMarin. In 2012, Firdapse was out-licensed to Catalyst, with BioMarin gaining a $5 million dollar stake in the company.