Prothena Reports 97% Revenue Decline and $125.8 Million Net Loss in Q2 2025

Prothena Corporation plc reported significant financial challenges in its latest quarterly filing, revealing a stark decline in revenue and a substantial net loss for the second quarter of 2025. The company generated total revenue of $4.4 million for the three months ended June 30, 2025, a dramatic decrease of 97% compared to $132.0 million in the same period last year. For the first half of 2025, total revenue was $7.2 million, down 95% from $132.1 million in the prior year. The decline in revenue was primarily attributed to the completion of revenue recognition under the Collaboration Agreement with Bristol Myers Squibb (BMS), which had contributed significantly to the previous year's figures.

Operating expenses for Prothena also increased, totaling $89.0 million for the second quarter of 2025, up 21% from $73.6 million in the same quarter of 2024. This rise was driven by restructuring costs of approximately $32.6 million associated with a workforce reduction of about 63%, following the decision to discontinue the development of birtamimab. Research and development expenses decreased by 30% to $40.5 million, reflecting lower clinical trial and manufacturing costs. The company reported a net loss of $125.8 million for the quarter, compared to a net income of $66.9 million in the prior year, resulting in a basic net loss per share of $2.34.

In terms of operational developments, Prothena's restructuring plan aims to streamline operations and reduce costs in light of the discontinuation of birtamimab. The company has also made significant strides in its clinical pipeline, with ongoing programs targeting Alzheimer’s disease and Parkinson’s disease. Notably, the company is advancing its lead candidate, PRX012, which is currently in a Phase 1 clinical trial, with initial data expected in August 2025. Additionally, Prothena has partnered with Roche and BMS for various drug candidates, which may provide future milestone payments and royalties.

As of June 30, 2025, Prothena reported cash and cash equivalents of $371.4 million, a decrease from $471.4 million at the end of 2024. The company believes this cash position is sufficient to meet its obligations for at least the next twelve months. However, it anticipates needing additional capital to support ongoing research and development efforts and to fund potential acquisitions or collaborations. The company’s accumulated deficit has now reached $1.3 billion, underscoring the financial pressures it faces as it navigates its restructuring and clinical development strategies.