Omeros Announces Online Publication in Advance of ASH Annual Meeting Detailing Narsoplimab Treatment Under Compassionate Use of 15 Patients with Hematopoietic Stem Cell Transplant-associated Thrombotic Microangiopathy

Omeros Corporation (Nasdaq: OMER) today announced online publication of a report detailing treatment with narsoplimab of 15 adult and pediatric patients with hematopoietic stem cell transplant-associated thrombotic microangiopathy (TA-TMA), 14 of whom had “high-risk” TA-TMA. Narsoplimab is Omeros’ investigational antibody targeting MASP-2, the effector enzyme of the lectin pathway of the complement system. The report was authored by an external group of investigators involved in the treatment of these patients with narsoplimab provided under Omeros’ compassionate use program.

The report will be featured as a poster presentation at the 65th Annual Meeting of the American Society of Hematology (ASH), to be held December 9-12, 2023 in San Diego. The abstract (#3543) is available on the ASH website at www.hematology.org or by clicking here.

The poster will be presented by Dr. Marta Castelli, Department of Oncology and Hematology, University of Milan and Azienda Socio-Sanitaria Territoriale Papa Giovanni XXIII, Bergamo, Italy. Details of the presentation are as follows:

Clinical Safety and Efficacy of Narsoplimab in Pediatric and Adult Patients with Transplant-Associated Thrombotic Microangiopathy: A Real-World Experience (Abstract #3543)
Session Name: 721. Allogeneic Transplantation: Conditioning Regimens, Engraftment and Acute Toxicities: Poster II
Date: Sunday, December 10, 2023
Presentation Time: 6:00 p.m. - 8:00 p.m. PT
Location: San Diego Convention Center, Halls G-H

About Narsoplimab

Narsoplimab, also known as “OMS721,” is an investigational fully human monoclonal antibody targeting mannan-binding lectin-associated serine protease-2 (MASP-2), a novel pro-inflammatory protein target and the effector enzyme of the lectin pathway of complement. Importantly, inhibition of MASP-2 has been demonstrated to leave intact the antibody-dependent classical complement activation pathway, which is a critical component of the acquired immune response to infection. A biologics license application (BLA) is pending before the U.S. FDA for use of narsoplimab in the treatment of hematopoietic stem cell transplant-associated thrombotic microangiopathy (TA-TMA), and Omeros expects to resubmit the BLA to include additional information supporting approval of narsoplimab in this indication. Narsoplimab is also in clinical development programs focused on other complement-mediated disorders, including COVID-19. FDA has granted narsoplimab breakthrough therapy and orphan drug designations for TA-TMA and orphan drug status for the prevention (inhibition) of complement-mediated thrombotic microangiopathies as well as for the treatment of TA-TMA. The European Medicines Agency has granted orphan drug designation to narsoplimab for treatment in hematopoietic stem-cell transplant.