Omeros Corporation Announces Update on European Marketing Authorization Application for Narsoplimab in TA-TMA

About this update from Omeros Corporation

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. “We are disappointed by the CHMP’s opinion, particularly given the lethal nature of TA-TMA, the absence of an approved treatment for this condition in Europe, and the totality of the clinical trial and real-world data supporting narsoplimab’s efficacy and safety,” said Gregory A. Demopulos, M.D., chairman and chief executive officer of Omeros. “We look forward to meeting with the AHEG and believe strongly that YARTEMLEA warrants approval in Europe, just as it received approval in the U.S. In the meantime, we plan to continue providing YARTEMLEA to TA-TMA patients under our global compassionate use program, prioritizing children. Given drug supply and access constraints, however, compassionate use in Europe can reach only a fraction of the patients who could be treated following EMA approval. While regulatory review progresses, we will work to make YARTEMLEA available to p...

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