Prothena (PRTA) Q4 2025 earnings summary

Executive summary

• Advanced partnered programs prasinezumab (Parkinson's), coramitug (ATTR-CM), BMS-986446 (Alzheimer's), and PRX019 (neurodegeneration) into later-stage trials, achieving significant clinical milestones in 2025.

• Introduced CYTOPE technology for precise intracellular targeting, with promising preclinical ALS data and ongoing partnership discussions.

• Strategic priorities for 2026 include capturing up to $105M in clinical milestones, implementing a share redemption program, and expanding research collaborations.

• Ended 2025 with $308.4M in cash and no debt, supporting ongoing and future development activities.

• Total 2025 revenue was $9.7M, down from $135.2M in 2024, primarily due to lower collaboration revenue.

Financial highlights

• Net cash used in operating and investing activities for 2025 was $163.7M, favorable to guidance.

• Net loss for 2025 was $244.1M, in line with guidance, including $37.6M in non-cash share-based compensation and $30.1M in restructuring charges.

• Year-end 2025 cash and equivalents totaled $308.4M, above guidance.

• No debt and 53.8M shares outstanding as of December 2025.

• Full year 2025 R&D expenses: $134.9M; G&A expenses: $59.4M, both down year-over-year.

Outlook and guidance

• 2026 net cash used in operating and investing activities expected to be $50M–$55M.

• Year-end 2026 cash projected at $255M, not including up to $105M in potential milestone payments.

• Estimated 2026 net loss of $67M–$72M, including $24M in non-cash share-based compensation.