Business Description

Overview Omeros Corporation (“Omeros,” the “Company” or “we”) is an innovative, commercial-stage biotechnology company that discovers and develops first-in-class protein and small-molecule therapeutics for large-market and orphan indications, with particular emphasis on complement-mediated diseases, cancers, and addictive or compulsive disorders. Our complement-targeted product, product candidates, and therapeutic programs are primarily focused on diseases and disorders associated with the lectin and/or alternative pathways of complement. Our lectin pathway program includes inhibitors of mannan-binding lectin-associated serine protease 2 (“MASP-2”) and our alternative pathway program includes inhibitors of mannan-binding lectin-associated serine protease 3 (“MASP-3”). Our Commercial Product: YARTEMLEA ® (narsoplimab-wuug) YARTEMLEA ® (narsoplimab-wuug) is the first and only approved therapy for hematopoietic stem cell transplant-associated thrombotic microangiopathy (“TA-TMA”), an often-fatal complication of stem cell transplantation driven by activation of the lectin pathway of complement. YARTEMLEA selectively inhibits MASP-2, the effector enzyme of the lectin pathway, blocking the pathway’s activation while preserving classical and alternative complement functions important for host defense against infection. YARTEMLEA was approved by the U.S. Food and Drug Administration (“FDA”) on December 23, 2025 for the treatment of TA-TMA in adult and pediatric patients aged two years and older. Unlike other complement inhibitors, YARTEMLEA has no boxed warning and no Risk Evaluation and Mitigation Strategy (“REMS”), and vaccinations are not required prior to treatment. Commercial distribution and sales of YARTEMLEA began in January 2026. A marketing authorization application (“MAA”) for YARTEMLEA in TA-TMA has been submitted to the European Medicines Agency (“EMA”) and is being reviewed under EMA’s centralized review procedure, which allows review of a single marketing authorization application. If the MAA is approved, it would authorize the product to be marketed in all EU member states and European Economic Area countries. The European Commission (the “EC”) has granted narsoplimab designation as an orphan medicinal product for treatment in hematopoietic stem cell transplantation. Our Partnered Program: Zaltenibart (OMS906) As part of our program to develop complement-targeted therapeutics, we identified MASP-3, which has been shown to be the key activator of the complement system’s alternative pathway (“APC”). The complement system is part of the immune system’s innate response, and the APC is considered the amplification loop within the complement system. MASP-3 is responsible for the conversion of pro-factor D to mature factor D; which is necessary for the activation of the APC. We believe that MASP-3 inhibitors have potential applications across a broad range of therapeutic areas and indications, including paroxysmal nocturnal hemoglobinuria (PNH), renal diseases such as immunoglobulin A nephropathy (IgAN), C3 glomerulopathy and atypical hemolytic uremic syndrome, as well as other immune and complement-driven disorders. On November 25, 2025, we completed a transaction (the “Transaction”) pursuant to an Asset Purchase and License Agreement (“APLA”) between Omeros and Novo Nordisk Healthcare AG (“Novo Nordisk”), dated October 10, 2025, in which Novo Nordisk received exclusive global rights in all indications to develop and commercialize our lead investigational MASP-3 inhibitor, zaltenibart (formerly OMS906), and certain related compounds and products. Zaltenibart is a first-in-class, late-stage clinical humanized monoclonal antibody targeting MASP-3, the most upstream and key activator of the alternative pathway of the complement system. Zaltenibart has shown multiple potential advantages over other alternative pathway inhibitors in development and on the market. At the closing of the Transaction, we received an upfront cash payment of $240.0 million. In addition, we are eligible to receive (i) up to $510.0 million in one-time milestone payments upon the first achievement by Novo Nordisk or its affiliates or sublicensees of each of the development and approval milestone events as set forth in the APLA and (ii) up to $1.3 billion in one-time milestone payments upon the first achievement by Novo Nordisk or its affiliates or sublicensees of certain sales-based milestone events as set forth in the APLA.…