Omeros Corp. (OMER) is making a second attempt to secure FDA approval for its investigational product, Narsoplimab, and a decision is expected on September 25, 2025.Narsoplimab is a human monoclonal antibody being developed for the treatment of hematopoietic stem cell transplant-associated thrombotic microangiopathy. Hematopoietic stem cell transplant-associated thrombotic microangiopathy (TA-TMA) is a significant and often lethal complication of stem cell transplantation. It is caused by endothelial cell damage induced by conditioning regimens, immunosuppressant therapies, infection, graft-versus-host disease, and other factors associated with stem cell transplantation. Thrombotic Microangiopathy can present with a range of clinical manifestations, including anemia, thrombocytopenia (low platelet count), impaired kidney function, and petechiae - tiny red or purple skin spots caused by subcutaneous bleeding. Other symptoms may include jaundice, abdominal pain, and neurological complications such as confusion, headaches, seizures, or even strokes.This is Narsoplimab’s second go-around with the FDA. The U.S. regulatory agency declined to approve Narsoplimab in October 2021, citing difficulty in estimating the treatment effect of Narsoplimab in HSCT-TMA and asserted that additional information would be needed to support regulatory approval.Addressing the concerns raised by the FDA, Omeros resubmitted the Biologics License Application for Narsoplimab in March of this year and now awaits the decision, which is due on the above-mentioned date. OMER closed Wednesday’s (Aug.27, 2025) trading at $4.25, down 2.97%.