Omeros Corp

Omeros Corporation is a commercial-stage biotechnology company that discovers and develops protein and small-molecule therapeutics. The company focuses on complement-mediated diseases, cancers, and addictive or compulsive disorders. Its complement-targeted products and programs primarily address diseases associated with the lectin and/or alternative pathways of complement. The lectin pathway program includes inhibitors of mannan-binding lectin-associated serine protease 2 ("MASP-2"), and the alternative pathway program includes inhibitors of mannan-binding lectin-associated serine protease 3 ("MASP-3"). Omeros's commercial product is YARTEMLEA® (narsoplimab-wuug), which is approved for hematopoietic stem cell transplant-associated thrombotic microangiopathy ("TA-TMA"). TA-TMA is a complication of stem cell transplantation driven by activation of the lectin pathway of complement. YARTEMLEA selectively inhibits MASP-2, blocking the lectin pathway's activation while preserving classical and alternative complement functions. The U.S. Food and Drug Administration ("FDA") approved YARTEMLEA on December 23, 2025, for adult and pediatric patients aged two years and older. Commercial distribution and sales of YARTEMLEA began in January 2026. A marketing authorization application for YARTEMLEA in TA-TMA has been submitted to the European Medicines Agency ("EMA") and is under review. The European Commission has granted narsoplimab orphan medicinal product designation for treatment in hematopoietic stem cell transplantation. Omeros also has a partnered program, Zaltenibart (OMS906), which targets MASP-3, identified as a key activator of the complement system's alternative pathway ("APC").