Prothena(PRTA) - 2025 Q4 - Annual Results

Exhibit 99.1 PRESS RELEASE Prothena Reports Fourth Quarter and Full Year 2025 Financial Results, and Provides Financial Guidance and Business Highlights DUBLIN, Ireland, February 19, 2026-- Prothena Corporation plc (NASDAQ:PRTA), a late-stage clinical biotechnology company with a robust pipeline of investigational therapeutics built on protein dysregulation expertise, today reported financial results for the fourth quarter and full year 2025. In addition, the Company provided business highlights and 2026 fi ...