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Prothena (PRTA)
NASDAQ:PRTA
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Prothena
(NASDAQ:PRTA)
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Rating:50Neutral
Price Target:
$9.00
▼(-0.22% Downside)
Action:ReiteratedDate:12/09/25
Prothena's overall stock score is primarily impacted by its financial challenges, including negative profitability and cash flows. While technical indicators show some positive momentum, the valuation remains a significant concern due to ongoing losses. The recent corporate event provides a positive outlook for financial flexibility, but strategic improvements are necessary for long-term growth.
Positive Factors
Innovative Drug Delivery
The development of CYTOPE, enabling cytosolic delivery of macromolecules, represents a significant advancement in targeting previously undruggable intracellular disease targets, potentially enhancing Prothena's competitive edge in neurodegenerative disease therapies.
Capital Reduction Approval
The approval of a capital reduction proposal is a positive development, potentially enhancing Prothena's financial flexibility and shareholder value by creating distributable reserves, which can be used for strategic investments or debt reduction.
Strategic Alliances
Prothena's strategic alliances with larger pharmaceutical firms enhance its financial resources and distribution network access, supporting long-term revenue generation and market reach, crucial for a clinical-stage biotech company.
Negative Factors
Negative Profitability
Persistent negative profitability metrics indicate ongoing financial challenges, limiting Prothena's ability to reinvest in R&D and potentially affecting long-term growth and sustainability unless addressed.
Cash Flow Challenges
Negative cash flows constrain Prothena's operational and growth capabilities, necessitating improved cash generation strategies to ensure financial stability and fund future development projects.
Revenue Decline
A significant decline in revenue growth reflects challenges in achieving development milestones or product commercialization, potentially impacting Prothena's ability to sustain operations and invest in new initiatives.
Prothena (PRTA) vs. SPDR S&P 500 ETF (SPY)
Market Cap
$489.31M
Dividend YieldN/A
Average Volume (3M)732.47K
Price to Earnings (P/E)―
Beta (1Y)1.01
Revenue Growth-91.16%
EPS Growth-112.24%
CountryUS
Employees163
SectorHealthcare
Sector Strength45
IndustryBiotechnology
Share Statistics
EPS (TTM)-0.40
Shares Outstanding53,829,983
10 Day Avg. Volume686,318
30 Day Avg. Volume732,465
Financial Highlights & Ratios
PEG Ratio0.34
Price to Book (P/B)1.53
Price to Sales (P/S)5.51
P/FCF Ratio-4.95
Enterprise Value/Market Cap0.38
Enterprise Value/Revenue15.57
Enterprise Value/Gross Profit-10.70
Enterprise Value/Ebitda-0.84
Forecast
1Y Price Target
$23.00Price Target Upside154.99% Upside
Rating ConsensusStrong Buy
Number of Analyst Covering5
EPS Forecast (FY)N/A
Revenue Forecast (FY)N/A
Prothena Business Overview & Revenue Model
Company DescriptionProthena Corporation plc, a late-stage clinical company, focuses on discovery and development of novel therapies for life-threatening diseases in the United States. The company is involved in developing Birtamimab, an investigational humanized antibody that is in Phase III clinical trial for the treatment of AL amyloidosis; Prasinezumab, a humanized monoclonal antibody, which is in Phase IIb clinical trial for the treatment of Parkinson's disease; PRX004 that completed Phase I clinical trial for the treatment of Transthyretin amyloidosis; and PRX005, which is in Phase I clinical trial for the treatment of Alzheimer's disease. Its discovery and preclinical programs include PRX012 for the treatment of Alzheimer's disease; and dual Aß-Tau vaccine for the treatment and prevention of Alzheimer's disease. Prothena Corporation plc has a license, development, and commercialization agreement with F. Hoffmann-La Roche Ltd. and Hoffmann-La Roche Inc. to develop and commercialize antibodies that target alpha-synuclein; and a collaboration agreement with Bristol-Myers Squibb to develop antibodies. The company was founded in 2012 and is based in Dublin, Ireland.
How the Company Makes MoneyProthena generates revenue primarily through collaborations and partnerships with pharmaceutical companies, which often involve upfront payments, milestone payments based on the achievement of specific development goals, and royalties on sales of approved products. The company may also receive funding from government grants and research institutions for specific projects. Prothena's strategic alliances with larger pharmaceutical firms can significantly enhance its financial resources and provide access to broader distribution networks, thereby contributing to its overall earnings. Additionally, any successful commercialization of its therapeutic candidates can lead to substantial revenues from product sales and licensing agreements.
Prothena Key Performance Indicators (KPIs)
Any
Revenue by Segment
Shows how much revenue each business segment generates, highlighting which parts of the company are driving growth and which may need strategic adjustments.
Shows how much revenue each business segment generates, highlighting which parts of the company are driving growth and which may need strategic adjustments.
Data provided by:
The Fly
The FlyProthena Earnings Call Summary
Earnings Call Date:Feb 19, 2026
(Q4-2025)
| % Change Since: |
Next Earnings Date:May 13, 2026
Earnings Call Sentiment Positive
The call conveyed meaningful scientific and business progress — two partner programs advanced to Phase III, strong Phase II biomarker signals (40% reduction in a PD motor endpoint subset; 48% NT‑proBNP reduction for coramitug), introduction of a novel CYTOPE technology with encouraging preclinical TDP‑43 results, and a solid year‑end cash position ($308.4M). Material near‑term upside exists (up to $105M in 2026 milestones and ~ $3B in potential future milestones across partners). Offsetting risks include ARIA‑E safety concerns for PRX012 prompting re‑engineering, some non‑statistically significant secondary endpoints (6‑minute walk test), multi‑year timelines to Phase III primary completions (2029), continued net losses and burn, and reliance on partner decisions for key programs (PRX019). Overall, positives — pipeline advancement, strong partner validation, and a healthy cash balance — outweigh the operational and timing risks.Q4-2025 Updates
Positive Updates
Two Partner Programs Advanced to Phase III
Roche advanced prasinezumab into the Phase III PARAISO trial (≈900 participants; primary completion expected in 2029). Novo Nordisk advanced coramitug into the Phase III CLEOPATTRA trial (≈1,280 patients; primary completion expected in 2029).
Strong Phase II Biomarker and Clinical Signals
Prasinezumab exploratory subset (patients on levodopa) showed a 40% relative reduction in MDS‑UPDRS Part III progression (nominal p=0.0177). Coramitug 60 mg/kg produced a 48% reduction in NT‑proBNP versus placebo (p=0.0017) and echocardiographic improvements suggestive of cardiac remodeling.
Robust Financial Position vs. Guidance
Year‑end 2025 cash and restricted cash of $308.4M (favorable to guidance of $298M). Net cash used in operating and investing activities was $163.7M (favorable to guidance $170M–$178M). Net loss of $244.1M was in line with guidance ($240M–$248M).
Material Near‑Term and Long‑Term Upside from Partnered Programs
Potential to earn up to $105M in aggregate clinical milestone payments in 2026 tied to coramitug enrollment targets and a BMS decision on PRX019. Aggregate partner programs could deliver up to approximately $3.0B in future milestone payments (in addition to royalties).
CYTOPE Platform and TDP‑43 Preclinical Progress
Introduced CYTOPE technology and presented TDP‑43 CYTOPE data showing systemic CNS activity in aggressive ALS mouse models, reduction of brain and muscle pathology, and attenuation of RNA mis‑splicing—supporting intracellular targeting capability.
PRX012 Clinical Activity Demonstrated
ASCENT Phase I interim results: mean amyloid PET reduction to ~27.5 centiloids at 12 months for patients on monthly 400 mg subcutaneous PRX012; preliminary 18‑month mean centiloid ≈16 with 9 of 12 patients (75%) achieving amyloid negativity (<24.1 centiloids).
Partnership and Development Momentum
BMS completed full enrollment in Phase II TargetTau‑1 (~310 patients) with primary completion expected H1 2027; BMS‑986446 received FDA Fast Track designation. Ongoing research collaboration(s) for CYTOPE with a large pharmaceutical company. Company approved for a 2026 share redemption program by shareholders and Irish High Court.
Negative Updates
ARIA‑E and Safety Profile Concerns for PRX012
PRX012 ASCENT reported ARIA‑E rates described as 'noncompetitive' relative to FDA‑approved anti‑Aβ antibodies, prompting a strategic pivot to a PRX012‑transferrin receptor (TfR) program to try to improve the ARIA profile.
Statistical Limitations in Some Phase II Endpoints
Coramitug showed an encouraging numerical improvement in the 6‑minute walk test at 60 mg/kg but this was not statistically significant, with Novo Nordisk attributing that to small sample size (105 patients total) and short study duration (12 months).
Long Timelines to Phase III Primary Completion
Primary completion dates for the two Phase III trials (PARAISO and CLEOPATTRA) are not expected until 2029, creating a multi‑year horizon before potential registration outcomes and material royalty revenue.
Substantial Ongoing Losses and Burn
Reported net loss of $244.1M for FY2025 and 2026 guidance anticipates net cash used in operating and investing activities of $50M–$55M and an estimated net loss of $67M–$72M, implying continued cash burn and a projected year‑end 2026 cash balance of approximately $255M (midpoint).
Dependence on Partner Decisions and Data Control
PRX019 is owned by Bristol Myers Squibb (BMS paid $80M and has global rights); Prothena conducts Phase I but BMS controls data dissemination and the decision to advance the program, making milestone realization and public data timing contingent on partner actions.
Uncertainty Around Mechanisms and Competitive Differentiation
Key hypotheses (e.g., how TfR modification reduces ARIA risk) remain unproven clinically beyond limited examples (e.g., trontinemab), and there are multiple competing TfR platforms which increases BD and technical risk for PRX012‑TfR and related programs.
Company Guidance
Prothena's 2026 guidance calls for full‑year net cash used in operating and investing activities of $50–55 million, an estimated net loss of $67–72 million (which includes about $24 million of noncash share‑based compensation), and an expected year‑end cash, cash equivalents and restricted cash balance of approximately $255 million at the midpoint; this guidance does not include up to $105 million of potential aggregate clinical milestone payments from partners in 2026. For context, Prothena closed 2025 with $308.4 million in cash (as of Dec 31, 2025), reported 2025 net cash used in operating and investing activities of $163.7 million (favorable to prior guidance of $170–178 million), a 2025 net loss of $244.1 million (in line with guidance of $240–248 million), had 53.8 million ordinary shares outstanding as of Feb 12, 2026, and a simple capital structure with zero debt.Prothena Financial Statement Overview
Summary
Prothena faces significant financial challenges, particularly in profitability and cash flow generation. Despite a low debt-to-equity ratio, the company struggles with negative net profit margins, EBIT margins, and cash flows. Strategic improvements in cost management and revenue generation are essential for enhancing financial performance.Income Statement
Prothena's income statement reveals significant challenges. The company has experienced negative net profit margins and EBIT margins over the years, indicating ongoing losses. While there was a revenue growth of 13.97% in the TTM, the gross profit margin is negative, suggesting cost management issues. The company needs to improve its profitability metrics to enhance its financial health.35
Negative
Balance Sheet
The balance sheet shows a low debt-to-equity ratio, which is a positive indicator of financial stability. However, the return on equity is negative, reflecting the company's inability to generate profits from its equity base. The equity ratio is relatively stable, but the company needs to focus on improving its return metrics to strengthen its financial position.50
Neutral
Cash Flow
Prothena's cash flow statement indicates negative operating and free cash flows, which are concerning. The free cash flow to net income ratio is close to 1, suggesting that cash flow is closely aligned with net income, albeit negative. The company must work on generating positive cash flows to support its operations and growth.40
Negative
| Breakdown | TTM | Dec 2024 | Dec 2023 | Dec 2022 | Dec 2021 | Dec 2020 |
|---|---|---|---|---|---|---|
Income Statement | ||||||
| Total Revenue | 11.79M | 135.16M | 91.37M | 53.91M | 200.58M | 853.00K |
| Gross Profit | -17.15M | 135.16M | 91.37M | 53.91M | 200.58M | -74.03M |
| EBITDA | -217.76M | -153.67M | -190.11M | -130.81M | 73.09M | -111.22M |
| Net Income | -280.46M | -122.31M | -147.03M | -116.95M | 66.97M | -111.14M |
Balance Sheet | ||||||
| Total Assets | 352.63M | 547.11M | 696.38M | 758.03M | 609.37M | 332.98M |
| Cash, Cash Equivalents and Short-Term Investments | 330.84M | 471.39M | 618.83M | 710.41M | 579.09M | 295.38M |
| Total Debt | 9.08M | 10.84M | 11.84M | 6.47M | 12.33M | 17.84M |
| Total Liabilities | 57.64M | 60.18M | 135.02M | 135.99M | 143.32M | 148.97M |
| Stockholders Equity | 294.99M | 486.93M | 561.37M | 622.04M | 466.04M | 184.01M |
Cash Flow | ||||||
| Free Cash Flow | -188.22M | -150.35M | -136.72M | -109.28M | 92.03M | -80.56M |
| Operating Cash Flow | -188.04M | -150.05M | -133.91M | -108.82M | 92.61M | -80.36M |
| Investing Cash Flow | -181.00K | -298.00K | -2.77M | -464.00K | -575.00K | -196.00K |
| Financing Cash Flow | -198.00K | 1.55M | 45.10M | 241.46M | 190.33M | 215.00K |
Prothena Technical Analysis
Neutral
9.02
Price Trends
9.32
Negative
9.82
Negative
8.41
Positive
Market Momentum
-0.12
Negative
47.67
Neutral
71.14
Neutral
Evaluating momentum and price trends is crucial in stock analysis to make informed investment decisions. For PRTA, the sentiment is Neutral. The current price of 9.02 is below the 20-day moving average (MA) of 9.06, below the 50-day MA of 9.32, and above the 200-day MA of 8.41, indicating a neutral trend. The MACD of -0.12 indicates Negative momentum. The RSI at 47.67 is Neutral, neither overbought nor oversold. The STOCH value of 71.14 is Neutral, not indicating any strong overbought or oversold conditions. Overall, these indicators collectively point to a Neutral sentiment for PRTA.
Prothena Risk Analysis
Prothena disclosed 62 risk factors in its most recent earnings report. Prothena reported the most risks in the "Tech & Innovation" category.
Finance & Corporate - Financial and accounting risks. Risks related to the execution of corporate activity and strategy
Latest Risks Added 0 New Risks
Prothena Peers Comparison
UnderperformOutperform
Sector (51)
Name | Overall Rating | Market Cap | P/E Ratio | ROE | Dividend Yield | Revenue Growth | EPS Growth |
|---|---|---|---|---|---|---|---|
59 Neutral | $1.52B | -32.77 | -35.82% | ― | ― | 79.27% | |
57 Neutral | $486.97M | 14.09 | 34.81% | ― | 240.47% | ― | |
55 Neutral | $301.53M | 32.73 | 16.22% | ― | 118.02% | ― | |
51 Neutral | $7.86B | -0.30 | -43.30% | 2.27% | 22.53% | -2.21% | |
50 Neutral | $489.31M | -1.73 | -67.63% | ― | -91.16% | -112.24% | |
50 Neutral | $3.43B | ― | -66.88% | ― | ― | 13.80% | |
45 Neutral | $522.02M | -8.02 | -45.92% | ― | 1255.21% | 74.58% |
* Healthcare Sector Average
PRTA
Prothena
9.02
-6.21
-40.77%
LXRX
Lexicon Pharmaceuticals
1.47
0.77
110.00%
XOMA
XOMA Royalty Corporation
25.81
2.28
9.69%
ZVRA
Zevra Therapeutics
8.80
1.35
18.12%
CRVS
Corvus Pharmaceuticals
16.57
12.48
305.13%
ALMS
Alumis Inc.
27.97
22.73
433.78%
Prothena Corporate Events
Executive/Board Changes
Prothena Board Member Paula Cobb Resigns
Neutral
Dec 12, 2025
On December 10, 2025, Paula Cobb announced her resignation from Prothena Corporation plc’s Board of Directors, effective December 31, 2025. Her departure is not due to any disagreements with the company’s operations, policies, or practices.
The most recent analyst rating on (PRTA) stock is a Hold with a $10.50 price target. To see the full list of analyst forecasts on Prothena stock, see the PRTA Stock Forecast page.
Shareholder Meetings
Prothena Shareholders Approve Capital Reduction Proposal
Positive
Nov 19, 2025
On November 19, 2025, Prothena Corporation held an extraordinary general meeting where shareholders approved a proposal to reduce the company’s capital to create distributable reserves. This decision is expected to impact the company’s financial flexibility and potentially enhance shareholder value.
The most recent analyst rating on (PRTA) stock is a Hold with a $11.00 price target. To see the full list of analyst forecasts on Prothena stock, see the PRTA Stock Forecast page.
Glossary
BuyA stock rated as a "Buy" is expected to perform better than the overall market or a specific benchmark over the near-to-medium term. This rating suggests the stock is likely to deliver higher returns compared to other stocks in the same sector or market index. Note: This is not investment advice; please consult a financial advisor before making investment decisions.
HoldA stock rated as a "Hold" is expected to perform in line with the overall market or a specific benchmark. This rating indicates that the stock is neither particularly compelling nor unfavorable for investment. Note: This is not investment advice; please consult a financial advisor before making investment decisions.
SellA stock rated as a "Sell" is expected to perform worse than the overall market or a specific benchmark over the near-to-medium term. This rating suggests the stock may deliver lower returns compared to other stocks in the same sector or market index. Note: This is not investment advice; please consult a financial advisor before making investment decisions.
Disclaimer
This AI Analyst Stock Report is automatically generated by our AI systems using advanced algorithms and publicly available financial, technical, and market data. While the information provided aims to be accurate and insightful, it is intended for informational purposes only and should not be considered financial advice. Any content created by an AI (Artificial Intelligence) system may contain inaccuracies and/or contain errors. Investing in stocks carries inherent risks, and past performance is not indicative of future results. This report does not account for your personal financial circumstances, objectives, or risk tolerance. Always conduct your own research or consult with a qualified financial advisor before making investment decisions. The analysis and recommendations provided are based on historical and current data and may not fully reflect future market conditions or unexpected developments. Neither the creators of this report nor its affiliated entities guarantee the accuracy, completeness, or reliability of the information presented. Use this report at your own discretion and risk.