Prothena (PRTA) Corporate presentation summary

Strategic priorities and financial outlook

• Up to $105 million in clinical milestones expected by year-end 2026, including a $50 million milestone for coramitug and a potential $55 million milestone for PRX019 advancement by BMS.

• Up to $100 million share repurchase plan authorized for 2026, supported by $308.4 million in cash as of December 31, 2025.

• Partnerships with Roche, Novo Nordisk, and Bristol Myers Squibb could yield up to $3 billion in aggregate downstream milestones and sales royalties.

• Roche partnership: up to $755 million in milestones and royalties for prasinezumab; Novo Nordisk: up to $1.23 billion for coramitug; BMS: up to $1.55 billion for BMS-986446 and PRX019.

Pipeline and clinical development

• Multiple active clinical programs: two partnered Phase 3, one partnered Phase 2, one partnered Phase 1, and several wholly owned preclinical programs.

• Prasinezumab (Parkinson's): Phase 3 PARAISO trial ongoing, primary completion expected in 2029.

• Coramitug (ATTR-CM): Phase 3 CLEOPATTRA trial ongoing, primary completion expected in 2029.

• BMS-986446 (Alzheimer's): Phase 2 TargetTau-1 trial ongoing, primary completion expected in 2027.

• PRX019 (neurodegeneration): Phase 1 trial ongoing, BMS decision on further development expected by year-end 2026.

Key clinical data and mechanisms

• Prasinezumab: Demonstrated ~40% reduction in Parkinson's disease progression at 2 years in Phase 2b, with favorable safety and tolerability.

• Coramitug: Phase 2 showed 48% reduction in NT-proBNP at 12 months vs. placebo and improvements in cardiac function; favorable safety profile.

• BMS-986446: Targets MTBR of tau, showing superior efficacy in blocking tau internalization and neurotoxicity in preclinical models; favorable safety in Phase 1.

• TDP-43 CYTOPE: Preclinical data show significant reduction of toxic aggregates and restoration of normal RNA splicing in ALS models.

• PRX012-TfR: Preclinical and early clinical data suggest rapid amyloid reduction and lower ARIA risk in Alzheimer's, with ongoing partnership discussions.