Prothena Corp. Plc (PRTA)

Over the past six months, Prothena's stock price has seen fluctuations. As of October 26, 2025, the stock was up 1.24% over this period, though it experienced a 41.62% decrease over the last year. In June 2025, Prothena announced a corporate restructuring, including a 63% workforce reduction, and Roche announced it would advance prasinezumab into Phase III development. In August 2025, the company reported its Q2 2025 financial results, missing analysts' consensus estimates, provided an update on its PRX012 program, and Novo Nordisk announced it would advance Coramitug into Phase 3 development. Between August and October 2025, several analyst rating and price target adjustments occurred. In October 2025, Prothena's partner Bristol Myers Squibb obtained Fast Track Designation from the U.S. FDA for BMS-986446 (PRX005).

Prothena Corporation Plc's revenue is primarily generated through strategic collaborations, licensing agreements, and milestone payments from its partners, rather than direct product sales to consumers. Therefore, traditional demand seasonality for products and services is not a significant factor in its business model. The company's financial performance is more closely tied to research and development milestones and clinical trial outcomes.

Prothena Corporation Plc is a clinical-stage biotechnology company focused on discovering and developing therapies for diseases caused by protein dysregulation, particularly neurodegenerative and rare peripheral amyloid diseases. Birtamimab is an investigational humanized antibody in Phase III clinical trials for AL amyloidosis. Roche is advancing prasinezumab, a humanized monoclonal antibody, into Phase III clinical development for Parkinson's disease and related synucleinopathies. Novo Nordisk is advancing NNC6019/Coramitug, an investigational antibody, into Phase III development for ATTR amyloidosis with cardiomyopathy. BMS-986446 (PRX005), an anti-MTBR-Tau-targeting antibody in Phase II clinical trials for Alzheimer's disease, has received Fast Track Designation from the U.S. FDA. PRX012 is an investigational antibody in Phase I clinical trials for Alzheimer's disease. PRX123 is a Dual Aβ-Tau Vaccine in preclinical trials for Alzheimer's disease. PRX019 is an investigational antibody in Phase I clinical trials for neurodegenerative diseases.

Prothena Corporation Plc is headquartered in Dublin, Ireland, and maintains significant operations in the United States. The company has a global focus, engaging in clinical development programs and regulatory activities across North America, Europe, and Asia.

Prothena's brand reputation in the past year has been influenced by its clinical development progress and corporate actions. Positive news includes advancements of its partnered programs, such as Roche moving prasinezumab into Phase III for Parkinson's disease and Bristol Myers Squibb receiving Fast Track Designation for BMS-986446 for Alzheimer's. However, the corporate restructuring in June 2025, which involved a significant workforce reduction, could have impacted its reputation. Analyst ratings have varied, with a consensus "Hold" rating, reflecting a mixed outlook.

Prothena Corporation Plc's ownership is primarily distributed among institutional investors, mutual funds, and individual shareholders. Approximately 97.08% of the stock is owned by institutional investors and hedge funds. Major institutional owners include Fmr Llc, BlackRock, Inc., ADAR1 Capital Management, LLC, Armistice Capital, Llc, Vanguard Group Inc, Palo Alto Investors LP, Federated Hermes, Inc., Citadel Advisors Llc, Acadian Asset Management LLC, and State Street Corp. Insiders hold about 10.00% of the stock. Notable individual/insider shareholders include Ecor1 Capital LLC and Oleg Nodelman.