Catalyst Pharmaceuticals Inc. a biopharmaceutical company focused on developing and commercializing innovative therapies for people with rare neuromuscular and neurological diseases, today announced positive top-line results from the investigator-sponsored trial evaluating Firdapse® (Amifampridine Phosphate) as a treatment for myasthenia gravis patients with anti-MuSK antibodies (MuSK-MG). MuSK-MG, is an ultra-rare sub-population of myasthenia Gravis (MG) patients which is a debilitating neuromuscular disease, and there are currently no FDA approved therapies for this specific form of MG. Both of the co-primary efficacy endpoints of change from baseline (CFB) in total Quantitative Myasthenia Gravis (QMG) score (p=0.0003) and CFB in total Myasthenia Gravis Activities of Daily Living (MG-ADL) score (p=0.0006) were statistically and clinically significant in this seven patient trial. Several secondary efficacy measures also achieved statistical significance. Amifampridine phosphate was well tolerated in this population of patients.
The study was conducted by a team of researchers led by Renato Mantegazza, MD, Director, Department of Neuroimmunology and Neuromuscular Diseases, Fondazione Istituto Neurologico Carlo Besta in Milan, Italy, a major referral center for MuSK-MG patients. The study was designed as a randomized (1:1), double-blind, placebo-controlled, crossover, outpatient study to evaluate the safety, tolerability and potential efficacy of amifampridine phosphate in patients diagnosed with MuSK-MG. Catalyst provided funding, study drug, and placebo for this trial.
Dr. Mantegazza, the principal investigator of this trial, stated, “Our prospective study evaluating amifampridine phosphate for the symptomatic relief of antibody positive MuSK-MG was statistically significant in demonstrating that it can be an important treatment option. Not only are the results statistically significant, but more importantly, there was a large clinical benefit to the patients. Current treatments for MuSK-MG patients are often inadequate and these patients often face a lifetime of severe complications, including difficulty walking, talking, swallowing, and breathing normally, and in some cases their disease may be life-threatening and require hospitalization and intensive care. Amifampridine phosphate may offer us an effective treatment option. I look forward to the day when I can use this drug in routine clinical practice of treating MuSK-MG patients.”
Dr. Silvia Bonanno, one of the investigators from the Istituto Neurologico Carlo Besta, is planning to present these results at the 13th International Conference on Myasthenia Gravis and Related Disorders in May, 2017 in New York City, provided her abstract is accepted as a Hot Topic Short Talk. This conference is organized by the Myasthenia Gravis Foundation of America and the New York Academy of Sciences.
“These data announced today should allow us to accelerate our MuSK-MG program over the coming months, as we expect to consult with our external experts and regulatory agencies on a pivotal clinical development plan,” said Patrick J. McEnany, Catalyst’s Chief Executive Officer. “I would like to thank Dr. Mantegazza, his associates at Carlo Besta Neurological Institute, and the patients that participated in this important clinical trial.”
"While several effective treatment options exist for the anti-acetylcholine receptor form of myasthenia gravis (AcHR-MG), MuSK-MG has been particularly refractory to current MG treatment options and represents an unmet medical need in the MG community of patients," stated Gary Ingenito MD, Ph.D., Catalyst's Chief Medical Officer. Dr. Ingenito continued: "If the significant clinical effect observed in this trial is reproduced in a multicenter trial, amifampridine phosphate would, upon approval, likely become the first line standard of care for MuSK-MG. Based on these results we intend to discuss with FDA conducting a registration trial in the United States evaluating amifampridine phosphate for the symptomatic treatment of patients with MuSK-MG."
