Prothena Corporation plc Q4 FY2022 earnings call

• Prothena is a late-stage clinical biotechnology company with a robust pipeline including four wholly-owned programs and five partner programs. • In 2022, advanced PRX012 and PRX005 into clinic, expect Phase 1 data from both; completed IND enabling studies for PRX123; prasinezumab evaluated by Roche in Phase 2b PADOVA and open-label extension of Phase 2 PASADENA; birtamimab in confirmatory Phase 3 AFFIRM-AL study; NNC6019 in Phase 2 study by Novo Nordisk. • Ended 2022 with $713M cash position, including $40M from Novo Nordisk milestone. • Highlighted breakthroughs in Alzheimer's disease, including lecanemab's approval and PRX012's potential as best-in-class subcutaneous treatment.

No detailed breakdown of product segments by revenue contribution in absolute terms provided in the transcript.

• 2023 net cash used in operating and investing activities expected to be between $213M and $229M, ending with ~$512M cash. • Milestones in 2023: PRX012 multiple ascending dose study to report top line data by end 2023; Phase 1 multiple ascending dose study for PRX005 to report top line data by end 2023; submit IND for PRX123 by end 2023. • Milestones in 2024: Roche reports top line data from Phase 2b PADOVA study for prasinezumab; AFFIRM-AL study reports top line data for birtamimab; Novo Nordisk reports top line Phase 2 data for NNC6019.

• Forward-looking statements subject to risks, uncertainties, and other factors that could cause actual results to differ materially from forward-looking statements. For discussion, see press release and SEC filings.

Q: Michael Yee at Jefferies asked about PRX012's Phase 1 MAD study, what to look for after six months and contextualizing PET data.

A: Gene Kinney, Tran Nguyen, and Hideki Garren responded discussing safety, pharmacokinetics, pharmacodynamics, and PET as a tool, with focus on active data and dose bracketing.

Q: Neena Bitritto-Garg at Citi asked about number of patients for PRX012 data and PET metrics.

A: Gene Kinney, Tran Nguyen, and Hideki Garren replied discussing Phase 1 study primary endpoint safety, pharmacokinetics, pharmacodynamics, and PET parameters.

Q: Charles Duncan at Cantor Fitzgerald asked about where PRX012 single dose data will be presented and subq target product profile.

A: Gene Kinney and Wagner Zago responded discussing announcement of data submission and acceptance, and key characteristics of PRX012 for subq administration.

Q: Jay Olson at Oppenheimer asked about reimbursement landscape for Alzheimer's therapeutics.

A: Gene Kinney and Tran Nguyen responded discussing CMS's announcement, potential for Part D reimbursement, and accelerated approval pathway.

Q: Brian Abrahams at RBC Capital Markets asked about future dosing paradigm for Alzheimer's beta amyloid antibodies and its impact on PRX012.

A: Gene Kinney and Wagner Zago responded discussing chronic treatment likely needed for Abeta targeting, and how different mechanisms affect dosing paradigms.

Q: Jason Butler at JMP Securities asked about PRX005's MAD results and biomarkers.

A: Gene Kinney, Hideki Garren, and Wagner Zago responded discussing MTBR region targeting, safety, tolerability, and CSF target engagement data expected by end 2023.