Prothena Past Earnings Performance
Past criteria checks 0/6
Prothena's earnings have been declining at an average annual rate of -34.7%, while the Biotechs industry saw earnings growing at 31.9% annually. Revenues have been declining at an average rate of 11% per year.
Key information
-34.73%
Earnings growth rate
-30.81%
EPS growth rate
| Biotechs Industry Growth | 17.04% |
| Revenue growth rate | -11.04% |
| Return on equity | -48.36% |
| Net Margin | -260.92% |
| Last Earnings Update | 31 Mar 2026 |
Recent past performance updates
Recent updates
Narrative Update • May 09
PRTA: Fast Track ATTR Program And Buybacks Will Support Future Upside
Analysts kept Prothena's fair value estimate steady at $21.00 with only small tweaks to the discount rate and long term assumptions, suggesting their price target is broadly unchanged while refining the supporting model inputs. What's in the News The U.S. FDA granted Fast Track Designation to coramitug, an amyloid depleter antibody in Phase 3 development for transthyretin amyloidosis with cardiomyopathy.Narrative Update • Apr 22
PRTA: ATTR Milestones And Share Repurchase Plan Will Support Future Upside
Analysts maintained Prothena's fair value estimate at $21.00, citing largely unchanged assumptions regarding revenue growth, profit margin, discount rate, and a very large future P/E multiple. What's in the News Prothena has earned $150 million to date out of up to $1.2 billion in eligible milestone payments from Novo Nordisk under their ATTR amyloidosis agreement.Narrative Update • Apr 02
PRTA: ATTR Milestones And Share Repurchase Will Drive Future Upside
Analysts have kept their price target for Prothena broadly unchanged at $21.00, with only slight adjustments to underlying assumptions on discount rate, revenue growth, profit margin and future P/E, in order to better reflect their current view of the stock's risk and earnings profile. What's in the News Prothena has earned $150 million to date of the total eligible milestone payments of up to $1.2 billion from Novo Nordisk under their ATTR amyloidosis agreement, including a recent $50 million milestone tied to a prespecified enrollment target in the ongoing Phase 3 CLEOPATTRA trial of coramitug for ATTR-CM (Key Developments).Narrative Update • Mar 19
PRTA: Share Buyback And ATTR Milestones Will Support Future Upside
Analysts have nudged their price target on Prothena to $21.00 from $20.50, reflecting updated assumptions on growth, margins, and a very large prospective future P/E multiple. What's in the News Prothena has earned a total of $150 million to date from potential milestone payments of up to $1.2 billion under its ATTR amyloidosis agreement with Novo Nordisk, tied to clinical development and sales milestones (Key Developments).Narrative Update • Mar 04
PRTA: Share Buyback And Index Inclusion Will Support Future Upside
Analysts now set their Prothena price target at about $20.50, compared with roughly $20.33 previously. This reflects updated assumptions around revenue growth, profit margins and future P/E levels.
New Narrative • Feb 23
Bullish View Expects Partnered Neurology Pipeline And CYTOPE Platform To Reshape Long-Term Prospects
Catalysts About Prothena Prothena is a late stage biotech company focused on protein misfolding and neurodegenerative diseases through partnered and wholly owned antibody and CYTOPE programs. What are the underlying business or industry changes driving this perspective?Narrative Update • Feb 18
PRTA: Index Inclusion And ALS Platform Milestones Will Drive Future Upside
Analysts maintained their Prothena fair value estimate at $20.33 per share, making only minor adjustments to assumptions such as discount rate, revenue growth, profit margin, and future P/E, which together support this unchanged price target. What's in the News Prothena Corporation plc was added to the S&P Biotechnology Select Industry Index, which can increase visibility for the stock among index-tracking funds and sector-focused investors (Key Developments).Narrative Update • Feb 03
PRTA: Future Milestones From ALS Platform And ATTR Program Will Drive Upside
Analysts have trimmed their price target for Prothena to about US$20.33 per share, reflecting slightly adjusted assumptions around discount rate, profit margin, and future P/E that fine tune rather than overhaul their prior view. What's in the News Prothena was added to the S&P Biotechnology Select Industry Index, putting the stock into a tracked industry benchmark that some index funds and ETFs follow (Index Constituent Adds).Narrative Update • Jan 20
PRTA: Partnered Royalties And Milestones Will Drive Upside Over Next 12 Months
Narrative update Analysts have lifted their price target on Prothena to US$36 from US$15, highlighting the value they see in the partnered pipeline and its potential for net sales royalties and milestone payments over the catalyst-heavy year ahead. Analyst Commentary Bullish analysts are pointing to the recent price target revision to US$36 as a signal that the market may be underappreciating the potential value of Prothena's partnered programs, especially the royalty and milestone streams that could build over time.Narrative Update • Jan 05
PRTA: Partnered Royalties And Milestones Will Drive Upside Over Catalyst-Rich Year
Narrative Update Analysts have raised their price target on Prothena to US$36 from US$15, citing what they describe as strong potential in the company's partnered pipeline, including expected net sales royalties and milestone payments over the coming year and in subsequent periods. Analyst Commentary Recent commentary from bullish analysts centers on the uplift in the price target to US$36, tied directly to how they see Prothena executing on its partnered programs and the potential cash flows that could come from those collaborations.Narrative Update • Dec 18
PRTA: Partnered Pipeline Milestones Will Drive Upside Over Catalyst-Rich Year Ahead
Analysts have significantly raised their price target on Prothena to $36 from $15, reflecting increased confidence in the lucrative potential of its partnered pipeline, including expected net sales royalties, milestone payments, and a catalyst-rich outlook over the next year. Analyst Commentary Bullish analysts highlight that the substantial price target increase is grounded in greater conviction around Prothena's partnered pipeline, which they see as a key driver of long term value creation and multiple expansion.Analysis Article • Dec 11
We Think Prothena (NASDAQ:PRTA) Can Afford To Drive Business Growth
Even when a business is losing money, it's possible for shareholders to make money if they buy a good business at the...Narrative Update • Dec 04
PRTA: Partnered Pipeline Milestones Will Drive Upside Over Catalyst-Rich Year Ahead
Analysts have lifted their fair value estimate for Prothena by about $2 per share, citing stronger long term revenue growth expectations from its partnered pipeline, lucrative royalty and milestone economics, and a robust catalyst calendar that they believe offers substantial upside potential. Analyst Commentary Recent adjustments to Prothena's valuation reflect a growing conviction that the company’s partnered programs and associated economics could materially enhance long term growth, though execution and timing risks remain key variables for investors.Narrative Update • Nov 20
PRTA: Upcoming Partnered Pipeline Milestones Will Drive Substantial Upside Over Next Year
Analysts have increased their price target for Prothena, raising it from $16.50 to $18.33. They cite optimism about the company's partnered pipeline and upcoming catalysts as key drivers for this upward revision.Narrative Update • Nov 05
PRTA: Upcoming Pipeline Milestones Will Drive Bullish Momentum Over Next 12 Months
Analysts have increased their price target for Prothena significantly, raising it from $15 to $36. They cite the company's strong partnered pipeline as well as substantial potential from upcoming catalysts and milestone payments.Narrative Update • Oct 22
Analysts Maintain Prothena Price Target as Valuation Adjustments Reflect Recent Clinical Results
Analysts have marginally raised their price target for Prothena from $13.00 to $13.00. They cited slight adjustments in discount rate and profit margin assumptions as drivers for the updated valuation.Narrative Update • Oct 08
AFFIRM-AL And Alzheimer's Trials Will Unlock New Opportunities
Analysts have raised Prothena's fair value estimate by $1.00 to $13.00, citing improved profit margin forecasts and a slightly lower projected future price-to-earnings ratio. What's in the News Prothena announced results from the Phase 1 ASCENT clinical program for PRX012 in early symptomatic Alzheimer's disease.Narrative Update • Sep 13
AFFIRM-AL And Alzheimer's Trials Will Unlock New Opportunities
Prothena’s consensus price target has been revised down to $12.00, reflecting weaker expectations primarily due to a notable decline in net profit margin and a reduced future P/E multiple. What's in the News Prothena reported Phase 1 ASCENT program results for PRX012 in early symptomatic Alzheimer's, showing stable pharmacokinetics, low immunogenicity, significant amyloid reduction, but higher ARIA-E rates compared to FDA-approved antibodies; company plans to seek partnerships for PRX012 and PRX012-TfR.Narrative Update • Aug 29
AFFIRM-AL And Alzheimer's Trials Will Unlock New Opportunities
Despite a sharp upward revision in both revenue growth and net profit margin forecasts for Prothena, the consensus analyst price target has significantly decreased from $24.29 to $15.00. What's in the News Phase 1 ASCENT results for PRX012 in early symptomatic Alzheimer's showed promising amyloid plaque reduction and pharmacokinetics, but higher ARIA-E rates than approved therapies; Prothena will seek partnership to advance PRX012 and its preclinical Ab-TfR antibody.Analysis Article • May 29
The Prothena Corporation plc (NASDAQ:PRTA) Analysts Have Been Trimming Their Sales Forecasts
One thing we could say about the analysts on Prothena Corporation plc ( NASDAQ:PRTA ) - they aren't optimistic, having...Seeking Alpha • May 27
Prothena: Despite Phase 3 Trial Failure, Other Neurodegenerative Programs In Place
Summary Prothena Corporation plc's phase 3 AFFIRM-AL trial for birtamimab in AL amyloidosis failed, leading to program termination and workforce reduction. Despite Phase 3 AL Amyloidosis trial failure, I maintain a Hold rating due to Prothena's robust pipeline, including Alzheimer's, Parkinson's, and ATTR-CM candidates. Key near-term catalysts include phase 1 PRX012 Alzheimer's data mid-2025 and other releases going forward, plus data updates for candidates prasinezumab and coramitug for PD and ATTR-CM. The Alzheimer's Disease market, in the 8 major markets [8MM] is expected to reach $19.3 billion by 2033; About between 5% to 6% of AD patients are early-symptomatic. Read the full article on Seeking AlphaAnalysis Article • May 22
Why Investors Shouldn't Be Surprised By Prothena Corporation plc's (NASDAQ:PRTA) 27% Share Price Plunge
Unfortunately for some shareholders, the Prothena Corporation plc ( NASDAQ:PRTA ) share price has dived 27% in the last...Analysis Article • Apr 02
Benign Growth For Prothena Corporation plc (NASDAQ:PRTA) Underpins Stock's 26% Plummet
Prothena Corporation plc ( NASDAQ:PRTA ) shares have had a horrible month, losing 26% after a relatively good period...
New Narrative • Mar 26
AFFIRM-AL And Alzheimer's Trials Will Unlock New Opportunities
Successful clinical trials for Birtamimab and Alzheimer's treatments could significantly boost Prothena's revenue through large market opportunities.Seeking Alpha • Mar 03
Prothena Corporation: Multiple Failures Make It Risky
Summary Prothena Corporation focuses on neurodegenerative diseases with a diverse pipeline, including Birtamimab for AL amyloidosis, which is in a phase 3 trial. Despite past trial failures, Birtamimab showed a survival benefit in severe AL amyloidosis patients, leading to a new phase 3 study. Financially, Prothena has a market cap of $850mn and a cash runway of 5-10 quarters, but is heavily spending on R&D. I recommend avoiding PRTA due to unpredictable upcoming data and past trial failures, making it risky and potentially un-investible. Read the full article on Seeking AlphaAnalysis Article • Feb 22
Prothena Corporation plc (NASDAQ:PRTA) Just Released Its Yearly Earnings: Here's What Analysts Think
It's been a good week for Prothena Corporation plc ( NASDAQ:PRTA ) shareholders, because the company has just released...Analysis Article • Jan 24
Insufficient Growth At Prothena Corporation plc (NASDAQ:PRTA) Hampers Share Price
With a price-to-sales (or "P/S") ratio of 6.2x Prothena Corporation plc ( NASDAQ:PRTA ) may be sending bullish signals...Seeking Alpha • Dec 22
Prothena Surges After Parkinson's Drug Misses Primary Endpoint
Summary Prothena's stock surged 34% despite Prasinezumab missing its Phase IIb primary endpoint, as Roche continues to invest. Prothena's pipeline includes multiple clinically staged drugs, with partnerships with major pharma companies, offering high-risk/high-reward potential. Investors should be cautious due to Prothena's 61% stock decline in 2024, but meaningful clinical success could create a buying opportunity. Prothena is rated as a HOLD, with upcoming catalysts in Parkinson's and Alzheimer's diseases that could fuel significant price appreciation. Read the full article on Seeking AlphaAnalysis Article • Nov 06
Prothena (NASDAQ:PRTA) Is In A Good Position To Deliver On Growth Plans
Just because a business does not make any money, does not mean that the stock will go down. For example, biotech and...Seeking Alpha • Oct 18
Prothena: Delays And Data Uncertainty Undermine Case For Investing (Downgrade)
Summary Prothena Corporation plc's stock has dropped 67% since my last “Buy” rating, primarily due to delays and a lack of meaningful Phase 1 data for PRX012. PRX012, targeting amyloid beta for Alzheimer's, is Prothena's key value driver but remains in Phase 1, lagging competitors with similar drugs. Birtamimab's Phase 3 data has also faced delays, and while promising, it competes in a crowded market with limited patient populations. Despite a strong cash position, Prothena's pipeline progress and competitive landscape justify a downgrade to “Hold” until more substantial data is available. Read the full article on Seeking AlphaAnalysis Article • Oct 02
Prothena Corporation plc (NASDAQ:PRTA) Looks Inexpensive After Falling 25% But Perhaps Not Attractive Enough
Prothena Corporation plc ( NASDAQ:PRTA ) shareholders won't be pleased to see that the share price has had a very rough...Analysis Article • Jul 26
Unpleasant Surprises Could Be In Store For Prothena Corporation plc's (NASDAQ:PRTA) Shares
You may think that with a price-to-sales (or "P/S") ratio of 14.9x Prothena Corporation plc ( NASDAQ:PRTA ) is a stock...Analysis Article • Jun 19
Companies Like Prothena (NASDAQ:PRTA) Are In A Position To Invest In Growth
There's no doubt that money can be made by owning shares of unprofitable businesses. For example, although Amazon.com...Seeking Alpha • Jun 07
Prothena: Potential For Future Price Drop On Failure Risk Of Late-Stage Trials
Summary Prothena Corporation is a late-stage biotech which specializes in proteinopathies and neurodegenerative diseases. They have a diverse pipeline. However, their main assets in attention currently are a first-in-class amyloid depleter, Birtamimab (wholly owned), and a Parkinson’s a-synuclein mAb, Prasinezumab (collab with Roche). Their revenue is primarily dependent on key milestone payments from collaborators. The stock has been dropping since its peak about a year ago, and I believe it still has room to drop for the foreseeable future due to the risk of failure of late-stage trials. Read the full article on Seeking AlphaAnalysis Article • May 14
New Forecasts: Here's What Analysts Think The Future Holds For Prothena Corporation plc (NASDAQ:PRTA)
Prothena Corporation plc ( NASDAQ:PRTA ) shareholders will have a reason to smile today, with the analysts making...Seeking Alpha • Feb 23
Prothena: Alzheimer's Data Update In 2024 Could Move The Needle
Summary Prothena Corporation plc has an update coming on the phase 1 study using PRX012 for the treatment of patients with Alzheimer's Disease, expected in 2024. Company is already in the process of exploring the use of PRX012 for the treatment of patients with Alzheimer's Disease in the ongoing phase 3 ASCENT-2 study. The global market for Alzheimer's Disease is estimated to reach $15.5 billion by 2031. BMS-986446 is being advanced in collaboration with Bristol-Myers Squibb with the big pharma having taken over the program going forward; Prothena received a $55 million milestone payment based off of it. Read the full article on Seeking AlphaRevenue & Expenses Breakdown
Revenue & Expenses Breakdown
How Prothena makes and spends money. Based on latest reported earnings, on an LTM basis.
Earnings and Revenue History
| Date | Revenue | Earnings | G+A Expenses | R&D Expenses |
|---|---|---|---|---|
| 31 Mar 26 | 58 | -151 | 54 | 0 |
| 31 Dec 25 | 10 | -244 | 59 | 0 |
| 30 Sep 25 | 12 | -280 | 64 | 0 |
| 30 Jun 25 | 10 | -303 | 67 | 0 |
| 31 Mar 25 | 138 | -110 | 67 | 0 |
| 31 Dec 24 | 135 | -122 | 67 | 0 |
| 30 Sep 24 | 133 | -132 | 67 | 0 |
| 30 Jun 24 | 217 | -51 | 67 | 0 |
| 31 Mar 24 | 89 | -172 | 66 | 0 |
| 31 Dec 23 | 91 | -147 | 62 | 0 |
| 30 Sep 23 | 141 | -73 | 58 | 0 |
| 30 Jun 23 | 58 | -141 | 53 | 0 |
| 31 Mar 23 | 55 | -128 | 52 | 0 |
| 31 Dec 22 | 54 | -117 | 50 | 0 |
| 30 Sep 22 | 5 | -156 | 49 | 0 |
| 30 Jun 22 | 143 | -1 | 49 | 0 |
| 31 Mar 22 | 202 | 67 | 47 | 0 |
| 31 Dec 21 | 201 | 67 | 46 | 0 |
| 30 Sep 21 | 200 | 69 | 44 | 0 |
| 30 Jun 21 | 61 | -70 | 41 | 0 |
| 31 Mar 21 | 1 | -124 | 40 | 0 |
| 31 Dec 20 | 1 | -111 | 39 | 0 |
| 30 Sep 20 | 1 | -102 | 37 | 0 |
| 30 Jun 20 | 1 | -91 | 36 | 0 |
| 31 Mar 20 | 1 | -80 | 36 | 0 |
| 31 Dec 19 | 1 | -78 | 36 | 0 |
| 30 Sep 19 | 1 | -79 | 36 | 0 |
| 30 Jun 19 | 1 | -84 | 36 | 0 |
| 31 Mar 19 | 1 | -128 | 38 | 0 |
| 31 Dec 18 | 1 | -156 | 42 | 0 |
| 30 Sep 18 | 1 | -181 | 49 | 0 |
| 30 Jun 18 | 1 | -209 | 52 | 0 |
| 31 Mar 18 | 27 | -167 | 52 | 0 |
| 31 Dec 17 | 28 | -153 | 48 | 0 |
| 30 Sep 17 | 27 | -154 | 35 | 0 |
| 30 Jun 17 | 28 | -145 | 39 | 0 |
| 31 Mar 17 | 1 | -168 | 36 | 0 |
| 31 Dec 16 | 1 | -160 | 32 | 0 |
| 30 Sep 16 | 1 | -135 | 38 | 0 |
| 30 Jun 16 | 1 | -115 | 28 | 0 |
| 31 Mar 16 | 1 | -93 | 25 | 0 |
| 31 Dec 15 | 2 | -81 | 23 | 0 |
| 30 Sep 15 | 3 | -70 | 21 | 0 |
| 30 Jun 15 | 4 | -60 | 20 | 0 |
Quality Earnings: PRTA is currently unprofitable.
Growing Profit Margin: PRTA is currently unprofitable.
Free Cash Flow vs Earnings Analysis
Past Earnings Growth Analysis
Earnings Trend: PRTA is unprofitable, and losses have increased over the past 5 years at a rate of 34.7% per year.
Accelerating Growth: Unable to compare PRTA's earnings growth over the past year to its 5-year average as it is currently unprofitable
Earnings vs Industry: PRTA is unprofitable, making it difficult to compare its past year earnings growth to the Biotechs industry (43%).
Return on Equity
High ROE: PRTA has a negative Return on Equity (-48.36%), as it is currently unprofitable.
Return on Assets
Return on Capital Employed
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Company Analysis and Financial Data Status
| Data | Last Updated (UTC time) |
|---|---|
| Company Analysis | 2026/05/18 08:30 |
| End of Day Share Price | 2026/05/15 00:00 |
| Earnings | 2026/03/31 |
| Annual Earnings | 2025/12/31 |
Data Sources
The data used in our company analysis is from S&P Global Market Intelligence LLC. The following data is used in our analysis model to generate this report. Data is normalised which can introduce a delay from the source being available.
| Package | Data | Timeframe | Example US Source * |
|---|---|---|---|
| Company Financials | 10 years |
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| Analyst Consensus Estimates | +3 years |
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| Market Prices | 30 years |
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| Ownership | 10 years |
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| Management | 10 years |
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| Key Developments | 10 years |
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* Example for US securities, for non-US equivalent regulatory forms and sources are used.
Unless specified all financial data is based on a yearly period but updated quarterly. This is known as Trailing Twelve Month (TTM) or Last Twelve Month (LTM) Data. Learn more.
Analysis Model and Snowflake
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Industry and Sector Metrics
Our industry and section metrics are calculated every 6 hours by Simply Wall St, details of our process are available on Github.
Analyst Sources
Prothena Corporation plc is covered by 24 analysts. 6 of those analysts submitted the estimates of revenue or earnings used as inputs to our report. Analysts submissions are updated throughout the day.
| Analyst | Institution |
|---|---|
| Geoffrey Meacham | Barclays |
| Tazeen Ahmad | BofA Global Research |
| null null | BTIG |