Prothena Corporation (PRTA) investor relations material

Recent corporate developments

• Multiple pipeline updates and positive news from partners, including Roche and Novo, with both moving key molecules into phase three studies this year.

• Restructuring led to a right-sized organization focused on ongoing partner obligations and new partnership opportunities.

• Shareholder-friendly financial activities, including plans for distributable reserves and potential share repurchase, are underway.

• Operational clarity and focus on near-term value creation, with $105M in clinical milestones achievable next year.

• End-of-year cash guidance is $300M, with further 2026 guidance to be provided early next year.

Pipeline and partnership updates

• Roche is advancing prasinezumab for Parkinson’s disease into phase three, with additional data expected and a large market opportunity projected.

• Novo Nordisk is moving Kuramitug for ATTR cardiomyopathy into phase three, with a significant milestone payment expected upon enrollment.

• Four active partnership programs: two entering phase three, one phase two readout in 2027, and one phase one with Bristol Myers Squibb.

• Ongoing efforts to partner unpartnered programs and fulfill R&D obligations for current collaborations.

• Partnership economics include up to $755M in milestones and royalties with Roche, and $1.23B in milestones and royalties with Novo Nordisk.

Clinical and scientific highlights

• PRX012, an anti-amyloid beta antibody for Alzheimer’s, showed strong potency and favorable PK but higher than expected ARIA rates; a transferrin-based approach is being considered to mitigate this.

• Prasinezumab targets aggregated alpha synuclein in Parkinson’s, with consistent effects across studies and a unique biological profile.

• Kuramitug targets misfolded transthyretin in ATTR amyloidosis, aiming to clear resident amyloid and prevent new aggregation, with encouraging early clinical data.

• Phase two and three studies are designed to address both symptomatic and disease-modifying aspects in neurodegenerative diseases.

• Future milestones include clinical data readouts, regulatory decisions, and potential commercial launches.