Catalyst Pharma down 48% after FDA says new Phase 3 study needed for Firdapse NDA

• Nano cap Catalyst Pharmaceuticals (CPRX -47.6%) craters on a 5x surge in volume in response to its announcement that it will need to conduct a new Phase 3 clinical trial to assess lead product candidate and Orphan Drug- and Breakthrough Therapy-tagged Firdapse (amifampridine phosphate) for the treatment of Lambert-Eaton myasthenic syndrome (LEMS), a rare autoimmune disorder characterized by muscle weakness in the limbs.
• The FDA informed the company of the requirement in a recent meeting during which they discussed a path forward for a resubmitted New Drug Application (NDA). Catalyst received a "Refusal to File" letter from the agency in February, meaning its initial application was incomplete and required additional supporting information over and above the Phase 3 LMS-002 study. The expected timeline for the new trial is not provided, but its was more than three years for the final data collection date for the primary endpoint in LMS-002. The entire study will run more than five years (estimated completion date in August).
• The company will also have to conduct several more short-term toxicology studies, which are expected to start soon.
• Previously: FDA rejects Catalyst Pharma's Firdapse NDA; shares slump 38% (Feb. 17)