Business Context and Reporting Period
Company: Prothena Corporation plc (PRTA)
Filing Type: Form 10-K (Annual Report)
Period Ended: December 31, 2025
Business Overview: Prothena is a late-stage clinical biotechnology company focused on protein dysregulation, developing therapies for neurodegenerative and rare peripheral amyloid diseases. The company operates a pipeline of wholly-owned and partnered programs targeting Parkinson's disease, ATTR amyloidosis, Alzheimer's disease, and ALS. Key partnerships include Roche (prasinezumab), Novo Nordisk (coramitug), and Bristol Myers Squibb (BMS-986446 and PRX019).
Key Financial Metrics
| Metric (in thousands) | 2025 | 2024 |
|---|---|---|
| Total Revenue | $9,684 | $135,157 |
| Net Loss | $(244,092) | $(122,310) |
| Research & Development Expenses | $134,852 | $222,519 |
| General & Administrative Expenses | $59,392 | $67,199 |
| Restructuring Costs | $30,080 | $0 |
| Cash and Cash Equivalents (Year End) | $307,531 | $471,388 |
| Working Capital | $274,350 | $436,911 |
| Accumulated Deficit | $(1,346,433) | $(1,102,341) |
Note: The filing does not provide specific gross margin or operating margin percentages due to the company's pre-commercial status and significant R&D expenditures.
Material Changes vs. Prior Period
- Revenue Decline: Total revenue decreased by 93% to $9.7 million from $135.2 million in 2024. This was primarily driven by a drop in collaboration revenue from BMS, which fell from $135.1 million to $9.6 million. The 2024 figure included a one-time recognition of $110.1 million related to the PRX019 Global License Agreement and $25.0 million from expired material rights.
- Increased Net Loss: Net loss widened to $244.1 million from $122.3 million. This increase was driven by a $43.3 million provision for income taxes (due to recording a full valuation allowance on deferred tax assets) and $30.1 million in restructuring costs, partially offset by lower R&D expenses.
- Restructuring: The company incurred $30.1 million in restructuring costs in 2025 following the discontinuation of the birtamimab program and a 63% workforce reduction announced in June 2025.
- R&D Efficiency: R&D expenses decreased by 39% to $134.9 million, attributed to the wind-down of the PRX012 and birtamimab programs and lower personnel costs.
Guidance, Outlook, and Risks
Outlook and Liquidity: Management believes cash and cash equivalents of $307.5 million are sufficient to meet obligations for at least the next twelve months. The company anticipates needing additional capital to fund future operations and clinical trials. Future funding is expected to come from collaboration payments (Roche, BMS, Novo Nordisk), public/private equity, or debt financings.
Key Pipeline Updates:
- Prasinezumab (Parkinson's): Roche initiated the Phase 3 PARAISO trial in Q4 2025 following positive Phase 2b PADOVA results.
- Coramitug (ATTR-CM): Novo Nordisk initiated the Phase 3 CLEOPATTRA trial in Q4 2025 following positive Phase 2 results showing significant reduction in NT-proBNP levels.
- BMS-986446 (Alzheimer's): BMS obtained Fast Track designation in October 2025 and is conducting the Phase 2 TargetTau-1 trial.
- PRX012 (Alzheimer's): Phase 1 ASCENT data showed dose-dependent amyloid reduction but higher ARIA-E rates; the company is exploring partnerships.
Risks and Contingencies:
- Capital Requirements: The company expects to incur losses for the foreseeable future and may never achieve profitability. Failure to secure additional capital could force delays or termination of clinical trials.
- Clinical Trial Risk: Success depends on the outcomes of late-stage trials (Phase 3 for prasinezumab and coramitug). Negative results could materially harm the business.
- Collaboration Dependence: Revenue and development progress are heavily reliant on partners (Roche, BMS, Novo Nordisk) executing their obligations.
- Valuation Allowance: The company recorded a full valuation allowance against federal, state, and Irish deferred tax assets, indicating uncertainty regarding future realization of tax benefits.
Investor Verification Checklist
- Cash Runway: Verify the sufficiency of the $307.5 million cash balance against the projected $50-55 million net cash burn for 2026 and the timeline for potential capital raises.
- Partnership Milestones: Monitor the initiation and enrollment progress of the Phase 3 PARAISO (Roche) and CLEOPATTRA (Novo Nordisk) trials, as these are critical value inflection points.
- Restructuring Completion: Confirm the finalization of the $30.1 million restructuring plan and the impact of the 63% workforce reduction on remaining R&D capabilities.
- Tax Provision Impact: Review the implications of the $43.3 million tax provision and the full valuation allowance on future financial statements if profitability is achieved.
- PRX012 Strategy: Assess the company's strategy for the PRX012 program given the higher ARIA-E rates observed in Phase 1 and the potential for partnership or discontinuation.