DUBLIN - Prothena Corporation plc (NASDAQ:PRTA), currently trading at $6.58, has announced the discontinuation of birtamimab development following the Phase 3 AFFIRM-AL clinical trial results, which failed to meet the primary endpoint of time to all-cause mortality and secondary endpoints. The decision includes ending the open label extension of the trial. The news has contributed to the stock’s significant decline from its 52-week high of $25.42.
The trial, which enrolled 207 newly diagnosed, treatment-naive patients with Mayo Stage IV AL amyloidosis, was unable to demonstrate the effectiveness of birtamimab. Despite the drug being generally safe and well-tolerated, it did not achieve statistical significance in improving mortality or in secondary measures such as the 6-minute walk test and the Short Form-36 version 2 Physical Component Score. According to InvestingPro, the company maintains a Fair financial health rating, though its profitability metrics show challenges with a negative EBITDA of -$137.71M in the last twelve months.
Gene Kinney, Ph.D., President and CEO of Prothena, expressed disappointment in the outcome, acknowledging the impact on patients and their families. The company has extended gratitude to all participants involved in the trial.
As a result of the trial’s outcome, Prothena plans to substantially reduce its workforce and cut ongoing operating expenses. These changes are part of a broader strategy to manage resources while the company awaits other data readouts and pipeline updates expected over the next 18 months. With a market capitalization of $355 million and current ratio of 9.0, InvestingPro analysis suggests the company appears undervalued at current levels. Subscribers can access detailed financial health metrics and 12+ additional ProTips for deeper insight. Prothena’s Board of Directors, led by Chair Daniel G. Welch, has emphasized the importance of this strategy for shareholder interests. Details regarding the reduction in operating expenses will be provided in June.
Despite the setback with birtamimab, Prothena looks forward to upcoming milestones, including initial data from the Phase 1 ASCENT clinical trials on PRX012 in Alzheimer’s disease expected in August, and updates from partnerships with Roche, Novo Nordisk, and Bristol Myers Squibb. Analysts maintain optimism, with consensus recommendations leaning strongly bullish and price targets ranging from $18 to $110 per share.
The information in this article is based on a press release statement from Prothena Corporation plc.
In other recent news, Prothena Corp has been the subject of analyst attention with updates on its financial and clinical developments. The company recently reported its first-quarter 2025 financial results, revealing approximately $420 million in cash reserves, and confirmed its end-of-year cash guidance at around $300 million. Prothena is also preparing for significant clinical milestones, with Phase 3 results for birtamimab in AL amyloidosis expected this quarter and findings for PRX012 in Alzheimer’s disease anticipated mid-year. H.C. Wainwright adjusted its price target for Prothena to $30, maintaining a Buy rating, after evaluating interim data on PRX012 that showed promising plaque reduction in Alzheimer’s patients without increasing ARIA levels. The firm highlighted Prothena’s strategic dosing decisions, which suggest confidence in the drug’s therapeutic potential. Meanwhile, Citizens JMP reduced its price target to $78, maintaining a Market Outperform rating, citing an increased fully diluted share count and the upcoming Phase 3 birtamimab data as key factors. Both firms continue to express optimism about Prothena’s ongoing clinical trials and their potential impact on the company’s future.
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