The Committee for Medicinal Products for Human Use concluded that the marketing-authorization application for narsoplimab failed to meet the necessary regulatory standards. The drug is intended to treat hematopoietic stem-cell transplant-associated thrombotic microangiopathy, a severe and frequently fatal condition occurring after bone-marrow procedures. While the treatment currently holds approval in the United States, this European rejection presents a significant hurdle for the company's international expansion strategy.

In response to the ruling, Omeros leadership announced plans to challenge the decision. The company intends to file a formal request for a re-examination of the application, seeking an additional review by an independent panel of external experts to address the committee's concerns.