Prothena(PRTA) - 2024 Q2 - Quarterly Results

Exhibit 99.1 PRESS RELEASE Prothena Reports Second Quarter 2024 Financial Results and Business Highlights • Net cash provided by operating and investing activities was $15.8 million in the second quarter and net cash used by operating and investing activities was$57.3 million for the first six months of 2024; quarter-end cash and restricted cash position was $565.0 million • Revised year-end cash guidance to be approximately$468 million in cash, cash equivalents and restricted cash, representing an increa ...