---
schema_version: "secwatch.filing_event.v1"
accession: "0001193125-23-298644"
form_type: "8-K"
ticker: "CPRX"
cik: "0001369568"
company_name: "CATALYST PHARMACEUTICALS, INC."
filed_at: "2023-12-19T23:59:59+00:00"
generated_at: "2026-06-07T10:26:17.520979+00:00"
event_type: "regulatory"
sentiment: "positive"
materiality_score: 0.6
calibrated_materiality_score: 0.6
confidence: "high"
source: SEC EDGAR
---

# Catalyst partner DyDo submits NDA in Japan for FIRDAPSE; milestone payment triggered

## Summary
- DyDo Pharma submitted NDA to PMDA for FIRDAPSE (amifampridine) 10 mg for LEMS in Japan.
- Submission based on favorable interim data after six months of the safety-phase registration study.
- Upon acceptance of NDA filing, Catalyst due JPY 200M (~$1.4M USD) milestone payment from DyDo.
- Territorial rights automatically expand to Asia, Central/South America; plans underway for global partnerships.
- PMDA review period expected to be a minimum of nine months from submission date.

## SEC filing metadata
- accession: 0001193125-23-298644
- form_type: 8-K
- ticker: CPRX
- cik: 0001369568
- company_name: CATALYST PHARMACEUTICALS, INC.
- filed_at: 2023-12-19T23:59:59+00:00
- event_type: regulatory
- sentiment: positive
- materiality_score: 0.6
- calibrated_materiality_score: 0.6
- confidence: high
- sec_items: 8.01, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1369568/000119312523298644/0001193125-23-298644-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1369568/000119312523298644/d676830d8k.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001193125-23-298644
- JSON: https://secwatch.observer/filing/0001193125-23-298644.json
- Plain text: https://secwatch.observer/filing/0001193125-23-298644.txt

This AI-assisted summary is a reading aid. Review the linked SEC EDGAR filing before relying on any specific claim.