March 1, 2024

Prothena to Report Fourth Quarter and Full Year 2023 Financial Results on February 15, 2024

Contacts

Investors

Mark Johnson, CFA, Vice President, Investor Relations

650-417-1974, [email protected]

Media

Michael Bachner, Senior Director, Corporate Communications

609-664-7308, [email protected]

Prothena Corporation plc (NASDAQ:PRTA), a late-stage clinical biotechnology company with a robust pipeline of investigational therapeutics built on protein dysregulation expertise, today announced that it will report its fourth quarter and full year 2023 financial results on Thursday, February 15, 2024 after the close of the U.S. financial markets. The announcement will be followed by a live audio conference call at 4:30 PM ET.

The conference call will be made available on the Company's website at www.prothena.com under the Investors tab in the Events and Presentations section. Following the live audio webcast, a replay will be available on the Company's website for at least 90 days.

To access the call via dial-in, please dial +1 (800) 715-9871 (U.S. and Canada toll free) or +1 (646) 307-1963 (international) five minutes prior to the start time and refer to conference ID number 1706941. A replay of the call will be available until February 22, 2024, via dial-in at +1 (800) 770-2030 (U.S. and Canada toll free) or +1 (609) 800-9909 (international), Conference ID Number 1706941.

About Prothena

Prothena Corporation plc is a late-stage clinical biotechnology company with expertise in protein dysregulation and a pipeline of investigational therapeutics with the potential to change the course of devastating neurodegenerative and rare peripheral amyloid diseases. Fueled by its deep scientific expertise built over decades of research, Prothena is advancing a pipeline of therapeutic candidates for a number of indications and novel targets for which its ability to integrate scientific insights around neurological dysfunction and the biology of misfolded proteins can be leveraged. Prothena’s pipeline includes both wholly-owned and partnered programs being developed for the potential treatment of diseases including AL amyloidosis, ATTR amyloidosis, Alzheimer’s disease, Parkinson’s disease and a number of other neurodegenerative diseases. For more information, please visit the Company’s website at www.prothena.com and follow the Company on Twitter @ProthenaCorp.

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