Both of these diseases are ultra-rare, with prevalences in the United States believed to be approximately 3,000 and 1,000-1,500 patients, respectively.
Catalyst CEO Patrick McEnany said: "The completion of our NDA submission for Firdapse represents the culmination of years of effort by our employees, investigators, clinical trial sites, and most importantly the patients and families of the LEMS and CMS communities.
"Our NDA submission includes more than 60 pre-clinical and clinical studies conducted over the past 5 years by both Catalyst and BioMarin Pharmaceutical. The submission of this NDA brings us one step closer to making a treatment for LEMS and CMS available to all patients, not just a selected few fortunate enough to be treated by physicians holding INDs to treat these diseases with experimental variations of 3,4-DAP. We look forward to working with the FDA during the regulatory process in pursuit of our goal of bringing Firdapse to patients suffering with LEMS and CMS."
The NDA submission includes a request for a Priority Review by the FDA. Previously, Firdapse has received Breakthrough Therapy designation from the FDA for the treatment of LEMS, as well as Orphan Drug designations for LEMS and CMS.
Shin Oh, M.D., Distinguished Professor Emeritus in the Department of Neurology at the University of Alabama at Birmingham School of Medicine, said, "As a clinician who treats patients with LEMS and CMS, there is a great deal of value in having an FDA approved drug that would include approved labeling and prescribing information, as well as pharmacovigilance. If Firdapse is approved by the FDA, patients currently without any access to effective drugs, which make up the vast majority, will be able to receive a treatment that has been shown to be both safe and highly effective."
About Lambert-Eaton Myasthenic Syndrome
Lambert-Eaton myasthenic syndrome, or LEMS, is a rare, debilitating and sometimes life-threatening autoimmune, neuromuscular disorder characterized primarily by progressive muscle weakness of the limbs. The disease is caused by an autoimmune response, where antibodies are formed against voltage-gated calcium channels on nerve endings in the neuromuscular junction, which damages the channels. These calcium channels are responsible for the transport of calcium ions that activate the biochemical machinery responsible for releasing acetylcholine.
Acetylcholine is the neurotransmitter responsible for causing muscles to contract, and the failure to release enough of this neurotransmitter results in muscle weakness in LEMS patients. Additionally, LEMS can be associated with an underlying malignancy, most commonly small-cell lung cancer (SCLC), and in some individuals, LEMS is the first symptom of such malignancy.
Based on currently available information, Catalyst believes that there are approximately 3,000 LEMS patients in the United States.
About Congenital Myasthenic Syndromes
Congenital myasthenic syndromes, or CMS, is a rare neuromuscular disease comprising a spectrum of genetic defects and is characterized by fatigable weakness of skeletal muscles with onset at or shortly after birth or early childhood; in rare cases symptoms may not manifest themselves until later in childhood. The severity and course of the disease are variable, ranging from minor symptoms to progressive disabling weakness; symptoms may be mild, but sudden severe exacerbations of weakness or even sudden episodes of respiratory insufficiency also occur.
Based on currently available information, Catalyst believes that there are between 1,000 and 1,500 CMS patients in the United States, who may benefit from treatment with Firdapse.