Welcome to our dedicated page for Prothena news (Ticker: PRTA), a resource for investors and traders seeking the latest updates and insights on Prothena stock.
Prothena Corporation plc (NASDAQ: PRTA) is described in its own press releases as a late-stage clinical biotechnology company focused on protein dysregulation in neurodegenerative and rare peripheral amyloid diseases. The PRTA news feed on Stock Titan aggregates these company communications, giving investors and observers a single place to follow Prothena’s disclosures and milestones.
In its recent news, Prothena has highlighted progress across a pipeline that includes both wholly-owned and partnered programs. Updates have covered clinical development for Parkinson’s disease through the prasinezumab collaboration with Roche, ATTR amyloidosis with cardiomyopathy via coramitug (formerly PRX004) now being developed by Novo Nordisk, and Alzheimer’s disease programs such as BMS-986446 (formerly PRX005) with Bristol Myers Squibb, PRX012, and the dual Aβ/tau vaccine PRX123. The company has also issued releases on its CYTOPE technology platform, workforce restructuring, and financial results.
Readers of the PRTA news page can review press releases on topics such as Phase 2 and Phase 3 trial plans, Fast Track designations, preclinical data from the TDP-43 CYTOPE program, and corporate actions including an Extraordinary General Meeting to approve a capital reduction to create distributable reserves. Governance and leadership updates, such as changes to the Board of Directors, are also disclosed through these announcements.
By following this curated stream of Prothena’s own news, users can see how the company presents the status of its investigational therapeutics, collaborations with partners like Roche, Novo Nordisk and Bristol Myers Squibb, and its capital and cost structure decisions. The PRTA news page is intended as a convenient starting point for reviewing Prothena’s publicly released information over time.
Prothena (NASDAQ:PRTA) partners presented clinical updates at AD/PD 2026 on prasinezumab (Roche) for Parkinson’s disease and BMS-986446 (Bristol Myers Squibb) for Alzheimer’s disease.
Key takeaways: PASADENA OLE outcomes suggested an estimated ~2 years “time saved” versus model predictions at five years; PADOVA OLE showed sustained slowing of progression and supportive neuromelanin/iron MRI biomarker signals. BMS reported single-dose safety, dose-proportional exposure and no anti-drug antibodies in healthy participants, including Japanese ethnicity.
Prothena (NASDAQ:PRTA) announced it earned a $50 million clinical milestone payment from Novo Nordisk after reaching a prespecified enrollment target in the Phase 3 CLEOPATTRA trial of coramitug (formerly PRX004) for ATTR amyloidosis with cardiomyopathy.
Prothena has now earned $150 million of a possible $1.2 billion in milestone payments under the 2021 asset sale; CLEOPATTRA targets ~1,280 participants with primary completion expected in 2029.
Prothena (NASDAQ:PRTA) authorized a share repurchase plan to buy up to $100.0 million of its ordinary shares through December 31, 2026.
The company reported $308.4 million in cash, cash equivalents and restricted cash and no debt as of December 31, 2025, and expects to end 2026 with about $255 million excluding repurchases and potential milestones. Prothena noted up to $105 million of potential 2026 clinical milestone payments from partners. Repurchases may occur in open market transactions, under Rule 10b-18, or via 10b5-1 plans, and may be suspended or discontinued at the company’s discretion.
Prothena (NASDAQ:PRTA) reported Q4 2025 net loss of $21.6M and full-year net loss of $244.1M. Quarter-end cash was $308.4M. 2026 guidance: net cash used in operations and investing of $50–55M and year-end cash around $255M (midpoint). Partners Roche, Novo Nordisk and Bristol Myers Squibb advanced Phase 3 or Phase 2 programs with primary completions expected in 2029 and potential partner milestones up to $105M in 2026.
Shareholders approved a capital reduction to enable a potential 2026 share redemption program; company expects to discuss results on a Feb 19, 2026 conference call.
Prothena (NASDAQ:PRTA) will report fourth quarter and full year 2025 financial results on February 19, 2026 after market close, followed by a live audio conference call at 4:30 PM ET.
The live webcast and replay will be available on the company's Investors page; phone dial-in and replay dial-in details and conference IDs were provided for U.S., Canada and international participants.
Prothena (NASDAQ:PRTA) announced that Paula Cobb will step down from its Board of Directors effective December 12, 2025 to become Chief Operating Officer at Manifold Bio.
Ms. Cobb served on the board for six years after joining in 2019 and was described as providing global development, business strategy and commercial expertise. The board now has 8 directors.
Prothena (NASDAQ:PRTA) will present preclinical data for its TDP-43 CYTOPE® program at Neuroscience 2025 on November 19, 2025 at 1:00 PM PT. The poster (PSTR440.04) reports that systemically administered TDP-43 CYTOPE distributed to the brain and periphery, internalized into the cytosol, colocalized with pTDP-43 pathology, and significantly reduced intracellular pTDP-43 in an rNLS8 mouse model of ALS.
In vitro data in rat and human neuronal lines and human iPSC motor neurons showed cytosolic internalization, clearance of pTDP-43 aggregates, and reduction of RNA dysregulation driven by cryptic exon inclusions. The results highlight CYTOPE as a modality for delivering large molecules into cells to target intracellular disease pathways.
Prothena (NASDAQ:PRTA) announced publication of Phase 2 data for coramitug in the American Heart Association journal Circulation and presentation at AHA Scientific Sessions on November 10, 2025. The Phase 2 trial was randomized, double-blind, and placebo-controlled in patients with ATTR amyloidosis with cardiomyopathy. Novo Nordisk has initiated the Phase 3 CLEOPATTRA outcomes trial (NCT07207811). Under a July 2021 deal, Novo Nordisk acquired Prothena’s ATTR program; Prothena may receive up to $1.2 billion in milestones, with $100 million already earned. Prothena is eligible for an additional clinical milestone tied to CLEOPATTRA enrollment criteria.
Prothena (NASDAQ:PRTA) reported Q3 2025 results and business updates on November 6, 2025, highlighting partnered Phase 3 starts, program milestones, and capital plans.
Key metrics: Q3 net loss $36.5M and YTD net loss $222.5M; Q3 revenue $2.4M and YTD revenue $9.7M; cash $331.7M as of Sept 30, 2025; and guidance for $170–$178M net cash used in operating and investing activities for full-year 2025 with ~$298M year-end cash (midpoint).
Pipeline and milestones: Roche plans a Phase 3 PARAISO start for prasinezumab by end-2025; Novo Nordisk initiated Phase 3 CLEOPATTRA for coramitug and will present Phase 2 data on Nov 10, 2025; BMS received Fast Track for BMS-986446 and continues Phase 2; potential to earn up to $105M in aggregate clinical milestones by end-2026. The board will seek shareholder approval on Nov 19, 2025 for a capital reduction to enable a potential 2026 share redemption program.
Prothena (NASDAQ:PRTA) will report its third quarter and first nine months of 2025 financial results on Thursday, November 6, 2025, after the U.S. market close.
Consistent with prior practice, the company announced it will not hold a conference call with this release. The announcement notes Prothena is a late-stage clinical biotechnology company focused on investigational therapeutics built on protein dysregulation expertise.