– Late-breaking abstract detailing interim data from ongoing clinical trial of OMS906 in treatment-naïve PNH patients selected for June 11, 2023 oral presentation –

Omeros Corporation (Nasdaq: OMER) today announced that data from a pre-specified interim analysis of its ongoing Phase 1b clinical trial of OMS906, the company’s lead MASP-3 inhibitor, in complement-inhibitor-naïve adults with paroxysmal nocturnal hemoglobinuria (PNH), a rare and life-threatening hemolytic blood disorder, will be shared at the 2023 European Hematology Association (EHA) Congress in Frankfurt, Germany. Identified as one of the top five late-breaking submissions by the Scientific Program Committee, the abstract was selected for oral presentation.

The presentation, entitled OMS906, A mannan-binding lectin-associated serine protease-3 (MASP-3) Inhibitor, Normalizes Hemoglobin Levels in Treatment-naïve PNH Patients: Interim Data from a Proof-of-Concept Clinical Trial, will be delivered by Jens Panse, MD, Senior Physician and Deputy Director of the Department of Hematology, Oncology, Hemostaseology and Stem Cell Transplantation, University Hospital RWTH Aachen, and Managing Medical Director of the Center for Integrated Oncology, Aachen, Germany.

Dr. Panse’s presentation will be delivered at the late-breaking oral session scheduled for 9:45-11:15 CEST on Sunday, June 11, 2023 and will be available by livestream to registered meeting attendees via the congress platform. The presentation abstract (#LB2714) was embargoed by EHA until 16:00 CEST today but now is freely accessible on EHA’s website. Following Dr. Panse’s presentation, Omeros will make available on its website the associated slides.

Also at this EHA congress, Morag Griffin, MBChB, FRCPath, Consultant in Haematology of St. James University Teaching Hospital, Leeds, United Kingdom, will present a poster describing findings from a single-ascending dose study evaluating OMS906 safety, pharmacokinetics and pharmacodynamics in healthy subjects. Dr. Griffin’s presentation is scheduled for 18:00-19:00 CEST on Friday, June 9, 2023 and will be available for viewing by registered attendees on the online EHA platform throughout the duration of the congress (June 8-11, 2023). The presentation abstract (#P787) is available to everyone on EHA’s website.

About PNH

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare, life-threatening acquired disorder that causes production of red blood cells lacking certain surface proteins (CD55 and CD59), making them vulnerable to destruction by the complement system. This leads to intravascular hemolysis (destruction of red blood cells within blood vessels) and extravascular hemolysis (when damaged red blood cells are removed by macrophages in the spleen or liver). Left untreated, PNH is associated with debilitating anemia, a high risk of thrombosis, fatigue, and a severely reduced survival rate. There remains a significant unmet need for PNH therapies, as a large proportion of patients treated with C5 inhibitors continue to experience hemolysis and approximately one third of them still require red blood cell transfusions.

About OMS906

OMS906 is an investigational human monoclonal antibody targeting mannan-binding lectin-associated serine protease-3 (MASP-3), the key activator of the complement system’s alternative pathway. The complement system plays a central role in inflammation and becomes activated as a result of tissue damage or microbial infection. Responsible for the conversion of pro-complement factor D to complement factor D, MASP-3 is believed to be the premier target in the alternative pathway – it has the lowest native circulating level and low relative clearance compared to the other alternative pathway proteins and, unlike C5 and C3 blockers, MASP-3 inhibition leaves intact the lytic arm of the classical pathway, important for fighting infection. Also, unlike other components of the alternative pathway, MASP-3 is believed not to be an acute phase reactant, which could provide a significant advantage to MASP-3 inhibitors, like OMS906, over other alternative pathway inhibitors. MASP-3 inhibitors are thought to have preventive or therapeutic effects across a broad range of diseases including paroxysmal nocturnal hemoglobinuria (PNH), hemolytic uremic syndrome (HUS), atypical HUS, traumatic brain injury, arthritis, wet age-related macular degeneration, ischemia-reperfusion injury, transplant-related complications and other immune-related disorders. Through its growing and exclusive intellectual property position, Omeros controls the use of MASP-3 inhibitors across a wide range of alternative pathway-related and other diseases and disorders.

About Omeros Corporation

Omeros is an innovative biopharmaceutical company committed to discovering, developing and commercializing small-molecule and protein therapeutics for large-market and orphan indications targeting immunologic disorders including complement-mediated diseases, cancers, and addictive and compulsive disorders. Omeros’ lead MASP-2 inhibitor narsoplimab targets the lectin pathway of complement and is the subject of a biologics license application pending before FDA for the treatment of hematopoietic stem cell transplant-associated thrombotic microangiopathy (TA-TMA). Narsoplimab is also in multiple late-stage clinical development programs focused on other complement-mediated disorders, including IgA nephropathy, COVID-19, and atypical hemolytic uremic syndrome. Omeros’ long-acting MASP-2 inhibitor OMS1029 is currently in a Phase 1 clinical trial. OMS906, Omeros’ inhibitor of MASP-3, the key activator of the alternative pathway of complement, is advancing across multiple clinical programs for alternative pathway-related diseases, including paroxysmal nocturnal hemoglobinuria (PNH) and complement 3 (C3) glomerulopathy. For more information about Omeros and its programs, visit www.omeros.com.

View source version on businesswire.com: https://www.businesswire.com/news/home/20230601005810/en/