Prothena
Develops investigational protein-dysregulation therapies with a partner-heavy clinical pipeline.
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Profile
Develops investigational therapies for diseases caused by protein dysregulation, with clinical programs spanning Parkinson's disease, ATTR amyloidosis, Alzheimer's disease, and broader neurodegeneration. Revenue and late-stage progress depend heavily on collaboration partners after birtamimab was discontinued and the workforce was reduced.
Develops investigational therapies for diseases caused by protein dysregulation, using an Elan/Athena antibody-discovery lineage. Current named programs include prasinezumab for Parkinson's disease, coramitug for ATTR amyloidosis, BMS-986446 for Alzheimer's disease, PRX019 for neurodegeneration, TDP-43 CYTOPE for ALS, and PRX012-TfR for Alzheimer's disease.
Operates from an Irish public-company base with Nasdaq-listed ordinary shares and one research-and-development segment rather than commercial product lines. Revenue is collaboration-driven, with Roche, Novo Nordisk, and Bristol Myers Squibb controlling or co-developing the most advanced clinical assets.
Execution now centers on supporting partnered trials, rebuilding wholly owned preclinical programs, and managing a smaller organization after birtamimab was discontinued. The business depends on trial outcomes, partner advancement decisions, milestone receipts, and regulatory approvals for investigational drugs.
Company facts
Key statistics
Year to date +1.4% · Average volume (30d) 463.8K
Analysts
Ratings
Target range
Latest analyst notes
| Date | Firm | Action | Prior rating | Rating | Prior target | Target |
|---|---|---|---|---|---|---|
| Jul 24, 2026 | H.C. Wainwright | Reiterate | Buy | $20 | $30 | |
| Mar 13, 2026 | Stifel Nicolaus | Target | $19 | |||
| Dec 1, 2025 | JMP Securities | Target | $11 | $19 | ||
| Dec 1, 2025 | Deutsche Bank | Target | $19 | |||
| Oct 28, 2025 | Piper Sandler | Reiterate | Overweight | $36 |
Earnings
EPS
Revenue
History
| Report date | EPS est | EPS | Surprise | Revenue est | Revenue | Surprise | Next session |
|---|---|---|---|---|---|---|---|
| Aug 6, 2026Q2 FY26 | −$0.39 | −$0.32 | +17.9% | $421.7K | $1.0M | +139.5% | +2.10% |
| May 7, 2026Q1 FY26 | −$0.31 | $0.52 | +267.7% | $808.9K | $51.1M | +6,215.2% | +2.00% |
| Feb 19, 2026Q4 FY25 | −$0.45 | −$0.44 | +2.2% | $1.3M | $21.0K | −98.4% | −0.11% |
| Nov 6, 2025Q3 FY25 | −$0.60 | −$0.67 | −11.7% | $666.7K | $2.4M | +262.2% | +4.76% |
Financial highlights
| 12 quarters | Q1 FY25 | Q2 FY25 | Q3 FY25 | Q4 FY25 | Q1 FY26 | Q2 FY26 | |
|---|---|---|---|---|---|---|---|
| Revenue | $2.8M | $4.4M | $2.4M | $21.0K | $51.1M | $1.0M | |
| Gross profit | $2.8M | $4.4M | −$26.5M | −$921.0K | $50.2M | $1.0M | |
| Operating income | −$65.6M | −$84.6M | −$40.2M | −$27.2M | $25.8M | −$21.1M | |
| Net income | −$60.2M | −$125.8M | −$36.5M | −$21.6M | $32.7M | −$18.6M | |
| Diluted EPS | −$1.12 | −$2.34 | −$0.68 | −$0.40 | $0.60 | −$0.36 | |
| Gross margin | 100.0% | 100.0% | -1,098.3% | -4,385.7% | 98.2% | 100.0% | |
| Operating margin | -2,319.0% | -1,914.4% | -1,666.3% | -129,576.2% | 50.5% | -2,089.2% |
Fiscal years (4-quarter sums)FY21 $200.6M · FY22 $53.9M · FY23 $91.4M · FY24 $135.2M · FY25 $9.7M
Revenue by product · Q2 FY26
Balance sheet, Jun 30, 2026Cash & short-term investments $288.2M · Total debt $7.0M · Total assets $302.6M · Shareholders' equity $286.9M
Dividends
No dividends on record.
Ownership
Shares outstanding 52.35M · Float 46.55M · 88.9% free float
Top shareholders13F · 13D/G · Form 4
| Holder | Shares | % outstanding | Form | Filed |
|---|---|---|---|---|
| FMR LLC | 7.20M | 13.75% | 13F | Aug 13, 2026 |
| EcoR1 Capital, LLC · 10 percent owner | 5.30M | 10.13% | Form 4 | May 6, 2025 |
| Rubric Capital Management LP | 5.00M | 9.55% | 13F | Aug 14, 2026 |
| BlackRock, Inc. | 4.87M | 9.30% | 13F | Aug 7, 2026 |
| Fennell Todd W. | 4.50M | 8.40% | 13G | Nov 12, 2025 |
Insider tradesForm 4
| Date | Insider | Role | Shares | Avg price |
|---|---|---|---|---|
| Aug 20, 2026 | William P. Scully | 10 percent owner | +50,000 | $8.79 |
| Aug 7, 2026 | William P. Scully | 10 percent owner | +37,500 | $8.62 |
| Jul 29, 2026 | Michael John Isaacs | officer: General Counsel & Company Sec. | −8,386 | $8.47 |
| Jul 29, 2026 | Anne Evans Kingston | officer: Chief Strategy Officer | −7,662 | $8.47 |
| Jun 16, 2026 | William P. Scully | 10 percent owner | +20,000 | $7.90 |
Peers
- Pfizer
Commercial ATTR-CM benchmark with tafamidis
- Alnylam Pharmaceuticals
RNAi ATTR franchise and next-generation TTR silencers
- BridgeBio Pharma
ATTR-CM stabilizer and emerging amyloid-depleter threat
- Eli Lilly
Approved anti-amyloid Alzheimer therapy at commercial scale
- Biogen
Anti-amyloid and tau programs in Alzheimer disease
- AC Immune
Clinical proteinopathy peer across alpha-syn, tau, and Abeta
- Ionis Pharmaceuticals
RNA-targeted ATTR franchise with AstraZeneca
- Denali Therapeutics
BBB-delivery neurodegeneration platform targeting tau, Abeta, SNCA
CompareAfter-hours close
| Company | Price | Change | |||||
|---|---|---|---|---|---|---|---|
| Prothena | $9.33 | 0.00% | $488.5M | — | — | 9.0 | −77.2% |
| Pfizer | $27.95 | −0.04% | $159.36B | 36.9 | 10.0 | 2.5 | +2.6% |
| Alnylam Pharmaceuticals | $240.00 | +1.22% | $31.73B | 40.1 | 26.7 | 6.6 | +66.9% |
| BridgeBio Pharma | $76.60 | +0.03% | $15.00B | — | — | 21.7 | +120.4% |
| Eli Lilly | $1,173.00 | −0.08% | $1.10T | 39.4 | 28.7 | 13.9 | +47.7% |
| Biogen | $218.19 | −0.14% | $32.28B | 38.7 | 16.5 | 3.2 | +3.4% |
| AC Immune | $2.65 | −0.56% | $269.7M | — | — | 12.5 | +498.6% |
| Ionis Pharmaceuticals | $61.05 | +0.02% | $10.15B | — | — | 11.6 | −40.7% |
| Denali Therapeutics | $24.00 | +0.04% | $3.81B | — | — | 1,056.9 | — |
| Median | 39.0 | 21.6 | 12.0 | +47.7% |