Prothena Q2 Revenue Drops 97%

Key Points

• GAAP revenue was $4.4 million for Q2 2025 and Revenue plummeted to $4.4 million in the second quarter of 2025, a 96.7% decline compared to the same period in 2024.

• GAAP net loss was $2.34 per share in Q2 2025, significantly wider than the estimated GAAP loss of $1.25 per share.

• A $32.6 million restructuring charge (GAAP) was recorded in Q2 2025 following the discontinuation of a major drug candidate, contributing to continued operating losses.

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Prothena (NASDAQ:PRTA), a biotechnology company focused on developing therapies for neurodegenerative diseases, released its second quarter 2025 results on August 4, 2025. The period saw notably weaker-than-expected performance, with GAAP EPS of -2.34 missing the analysts' estimate of -1.25 and a much larger GAAP net loss than anticipated. Reported GAAP revenue was $4.4 million. The company posted a GAAP loss per share of $2.34, missing the estimated GAAP loss of $1.25 per share. The quarter was shaped by the discontinuation of the birtamimab program, a restructuring charge of $32.6 million, and the absence of significant collaboration revenue that boosted results in the prior year.

Source: Analyst estimates provided by FactSet. Management expectations based on management's guidance, as provided in Q1 2025 earnings report.

Company Overview and Focus Areas

Prothena develops experimental drugs designed to treat neurodegenerative and amyloid diseases, including Parkinson's, Alzheimer's, and various forms of amyloidosis. Its core approach centers on advancing a pipeline of potential therapies in areas with limited or no effective treatments. Key investigational products include prasinezumab (an antibody for Parkinson’s disease), PRX012 (an antibody for Alzheimer’s disease), and a suite of other candidates targeting protein misfolding disorders.

The company’s success hinges on advancing its drug candidates through clinical trials, securing strategic partnerships for funding and commercialization, and maintaining a robust patent portfolio. Collaborations with established pharmaceutical companies such as Roche and Bristol Myers Squibb are central to its strategy, as these partnerships provide milestone payments and validate its science. Navigating regulatory paths and reaching critical trial milestones will be decisive for future revenue prospects.

Highlights and Developments in the Quarter

Prothena’s GAAP revenue fell sharply to $4.4 million in Q2 2025 from $132.0 million in Q2 2024, almost entirely due to lower collaboration payments from pharmaceutical partners. This pattern highlights the company’s reliance on irregular partner funding as it does not yet sell any approved medicines.

The company reported a GAAP net loss of $125.8 million in Q2 2025, a sharp reversal from GAAP net income in Q2 2024. The wider loss was driven by several factors, including the absence of major milestone receipts and a restructuring charge related to the discontinuation of its birtamimab program for amyloidosis. Restructuring costs totaled $32.6 million and covered severance payments, contract terminations, and option vesting accelerations as the company reduced its workforce and wound down related manufacturing activities.

Research and development expense (GAAP) fell by 29.5% in Q2 2025 compared to Q2 2024. The decline was primarily due to lower clinical trial, manufacturing, and personnel expenses. General and administrative costs (GAAP) held steady year over year. The company ended Q2 2025 with $372.3 million in cash and no debt. Prothena also stated it expects to finish 2025 with approximately $298 million in cash, cash equivalents, and restricted cash, planning for net cash usage in the range of $170–$178 million for operating and investing activities for the full year 2025.

Progress in the pipeline remained a focus. The Parkinson’s antibody prasinezumab, now under the direction of Roche, is scheduled to enter Phase 3 testing by the end of 2025, targeting a population with significant unmet needs. PRX012, the company’s Alzheimer’s antibody, has Phase 1 data expected in August 2025, and has earned a Fast Track regulatory designation. Other programs, such as the vaccine PRX123 for Alzheimer’s and PRX019 for neurodegeneration (the latter partnered with Bristol Myers Squibb), continue to move through early development. Prothena is eligible for sizable milestone payments in the coming years if partnered programs hit development goals, including up to $105 million in aggregate clinical milestone payments in 2026 related to the advancement of coramitug for ATTR amyloidosis with cardiomyopathy by Novo Nordisk and PRX019 for neurodegenerative diseases by Bristol Myers Squibb. No dividend was paid or declared, and the company does not currently pay a dividend.

Looking Forward

For fiscal 2025, management guided investors to expect net cash used in operating and investing activities between $170 million and $178 million for fiscal 2025, with a projected year-end cash balance near $298 million in cash, cash equivalents, and restricted cash. Estimated full-year net loss (GAAP) will range from $240 million to $248 million for fiscal 2025, reflecting ongoing research costs and non-cash charges, such as share-based compensation and tax expense.

Despite current operational losses, upcoming clinical data releases represent important catalysts for investor attention. Pipeline advances—especially trial results for PRX012 and Phase 3 plans for prasinezumab—are critical future milestones. Prothena’s cash position and the potential for future milestone receipts from partners like Roche, Bristol Myers Squibb, and Novo Nordisk will be pivotal in the quarters ahead. The company did not provide detailed revenue or earnings guidance beyond the cash and loss forecasts.

PRTA does not currently pay a dividend.

Revenue and net income presented using U.S. generally accepted accounting principles (GAAP) unless otherwise noted.

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