• Presentations Highlight Progress in Late-Stage Development of Lead MASP-3 Inhibitor Zaltenibart 

SEATTLE / Dec 02, 2024 / Business Wire / Omeros Corporation (Nasdaq: OMER) today announced that two abstracts directed to zaltenibart (OMS906), Omeros’ investigational inhibitor of MASP-3, the key activator of the alternative pathway of complement, will be presented at the 66th Annual Meeting of the American Society of Hematology (ASH), to be held December 7-10, 2024 in San Diego. The zaltenibart abstracts are directed to the treatment of paroxysmal nocturnal hemoglobinuria (PNH), a rare, life-threatening hematological disorder. Enrollment for the zaltenibart Phase 3 clinical trials in PNH is expected to open in early 2025.

Both abstracts are available on the ASH website at www.hematology.org. Details of the congress presentations and direct links to the abstracts are found below.

Monotherapy Treatment with Zaltenibart (OMS906), an Alternative Pathway Masp-3 Inhibitor, Improved Key Hematologic Parameters in Patients with PNH with a Suboptimal Response to Ravulizumab: Interim Results from a Phase 2 Proof-of-Concept Study
Abstract Number / Link: 4072
Session: 508. Bone Marrow Failure: Acquired: Poster III
Presentation Time: Monday, December 9, 2024, 6:00 PM-8:00 PM
Location: San Diego Convention Center, Halls G-H
Presenting Author: Morag Griffin, MBChB, MRCP

Population Pharmacokinetics/Pharmacodynamics and Clinical Pharmacology of Zaltenibart (OMS906) in Healthy Subjects and Patients with PNH
Abstract Number / Link: 4081
Session: 508. Bone Marrow Failure: Acquired: Poster III
Presentation Time: Monday, December 9, 2024, 6:00 PM-8:00 PM
Location: San Diego Convention Center, Halls G-H
Presenting Author: William Pullman, BMedSc, MBBS, PhD, FRACP

The presentation materials associated with each abstract will be made available on Omeros’ website at www.omeros.com following the congress presentations.

About OMS906

OMS906 is an investigational human monoclonal antibody targeting mannan-binding lectin-associated serine protease-3 (MASP-3), the key and most proximal activator of the complement system’s alternative pathway. The complement system is a critical part of innate immunity and plays a central role in host homeostasis and defense against pathogens. 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, geographic atrophy or “dry” macular degeneration, ischemia-reperfusion injury, transplant-related complications and other immune-related disorders.

About Omeros Corporation

Omeros is an innovative biopharmaceutical company committed to discovering, developing and commercializing first-in-class small-molecule and protein therapeutics for large-market and orphan indications targeting immunologic disorders, including complement-mediated diseases and cancers, as well as 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. Omeros’ long-acting MASP-2 inhibitor OMS1029 has successfully completed Phase 1 single- and multiple-ascending dose clinical studies. OMS906, Omeros’ inhibitor of MASP-3, the key activator of the alternative pathway of complement, is advancing toward Phase 3 clinical trials for paroxysmal nocturnal hemoglobinuria and complement 3 glomerulopathy. Funded by the National Institute on Drug Abuse, Omeros’ lead phosphodiesterase 7 inhibitor OMS527 is in clinical development for the treatment of cocaine use disorder. Omeros also is advancing a broad portfolio of five novel cellular and molecular immuno-oncology programs. For more information about Omeros and its programs, visit www.omeros.com.