Omeros Corporation (NASDAQ:OMER) announced today an update on the review by the Committee for Medicinal Products for Human Use (CHMP) of the European Medicines Agency (EMA) of the company’s marketing authorization application (MAA) for narsoplimab for the treatment of hematopoietic stem cell transplant-associated thrombotic microangiopathy (TA-TMA).

Following an oral explanation meeting with the CHMP held this week, at which Omeros presented its position together with four international experts in hematopoietic cell transplantation, Omeros was informed that the CHMP has adopted a negative opinion on the MAA for narsoplimab in TA-TMA.

Omeros intends to request re-examination of the CHMP opinion and, as part of that procedure, to seek review of the matter by an Ad Hoc Expert Group (AHEG), an independent panel of external scientific and clinical experts to be convened by EMA based on relevant expertise in the indication and related clinical considerations.

Narsoplimab was approved under the brand name YARTEMLEA® by the U.S. Food and Drug Administration (FDA) in December 2025. Broadly indicated for all TA-TMA patients two years of age and older, it is the first and only treatment to receive regulatory approval for TA-TMA. YARTEMLEA targets MASP-2, the effector enzyme of the lectin pathway of complement and, with a unique safety profile, is the only systemic complement inhibitor on the market without a boxed warning, risk evaluation and mitigation strategy (REMS), or vaccination requirement.