Catalyst Pharmaceuticals has reported that its sub-licensee in Japan, DyDo Pharma has launched FIRDAPSE® (amifampridine) Tablets 10 mg in Japan for the indication of improving muscle weakness in patients living with Lambert-Eaton myasthenic syndrome (LEMS).

"We are pleased that our sub-licensee, DyDo, has launched FIRDAPSE in Japan. We believe in health equity, and this launch is a testament to our ongoing efforts to increase patient access to life-changing therapies worldwide,” said Richard J. Daly, Catalyst’s President and Chief Executive Officer.

“The launch of FIRDAPSE in Japan marks another advancement in our efforts to expand the geographic footprint of our portfolio products and paves the way for healthcare providers and patients in Japan to access this therapy," Daly added.

FIRDAPSE (amifampridine) is the only US FDA approved, evidence-based therapy for the treatment of LEMS in adults and pediatric patients six years of age and older. LEMS is a rare autoimmune disorder characterized by muscle weakness and fatigue. As a cornerstone of Catalyst's commitment to serving those with rare diseases, FIRDAPSE is supported in the US by a comprehensive patient support program to help ensure accessibility and assistance for eligible US patients.

FIRDAPSE® (amifampridine) Tablets 10 mg is an oral, nonspecific, voltage-dependent, potassium (K+) channel blocker that causes depolarization of the presynaptic membrane and slows or inhibits repolarization. This action results in the opening of slow voltage-dependent calcium (Ca2+) channels, allowing for a subsequent influx of Ca2+.

In turn, it induces the exocytosis of synaptic vesicles containing acetylcholine (ACh) to release more ACh into the synaptic cleft, enhancing neuromuscular transmission and providing for improved muscle function.

Amifampridine phosphate was granted orphan drug designation by the Ministry of Health, Labor, and Welfare in Japan, and FIRDAPSE has previously been approved for use in the US in adults and pediatric patients six years of age and older and in Europe and Canada for the treatment of adults with LEMS.