Prothena Reports Q3 2025 Revenue Increase to $2.4M, Net Loss of $36.5M

Prothena Corporation plc reported its financial results for the third quarter of 2025, revealing a total revenue of $2.4 million, a significant increase from $970,000 in the same period last year. However, for the nine months ending September 30, 2025, total revenue dropped to $9.7 million from $133.0 million in 2024, primarily due to a substantial decline in collaboration revenue, which fell from $132.9 million to $9.6 million. The decrease in revenue was attributed to the expiration of certain collaboration agreements and a shift in focus towards ongoing clinical trials, particularly the PRX019 Phase 1 Clinical Trial Obligation.

The company's operating expenses for the third quarter were $42.7 million, down from $67.5 million in the prior year, reflecting a 37% reduction. This decline was driven by a 43% decrease in research and development expenses, which totaled $28.9 million, as well as a 21% reduction in general and administrative expenses. The company also incurred restructuring costs of $479,000 during the quarter, part of a broader restructuring plan initiated in June 2025, which included a workforce reduction of approximately 63% to streamline operations and reduce costs.

Prothena's net loss for the third quarter was $36.5 million, or $0.68 per share, compared to a net loss of $59.0 million, or $1.10 per share, in the same quarter of 2024. The company reported a total net loss of $222.5 million for the nine months ended September 30, 2025, compared to $64.4 million for the same period in 2024. The increase in net loss was largely due to the significant drop in revenue and ongoing operational costs, including restructuring expenses.

In terms of operational developments, Prothena has made strategic advancements in its clinical pipeline, particularly with its lead candidate prasinezumab for Parkinson's disease, which is set to enter Phase 3 trials by the end of 2025. The company also continues to collaborate with major partners such as Roche and Bristol Myers Squibb, with potential milestone payments that could provide additional revenue streams. As of September 30, 2025, Prothena had cash and cash equivalents of $330.8 million, down from $471.4 million at the end of 2024, indicating a need for future capital to support ongoing and planned clinical trials.

Looking ahead, Prothena anticipates that its existing cash reserves will be sufficient to meet obligations for at least the next twelve months. However, the company acknowledges the potential need for additional capital to fund its research and development activities and to support its clinical programs. The management remains focused on advancing its pipeline and exploring strategic partnerships to enhance its financial position and operational capabilities.