Narsoplimab (OMS721) is our lead antibody targeting MASP-2, the effector enzyme of the lectin pathway of complement.

Narsoplimab (OMS721)

Narsoplimab is a human monoclonal antibody targeting mannan-binding lectin-associated serine protease-2 (MASP-2), the effector enzyme of the lectin pathway of the complement system. The lectin pathway is one of the principal pathways of complement and is activated primarily by tissue damage and microbial infection. Importantly, inhibition of MASP-2 does not appear to interfere with the classical complement pathway, a critical component of the acquired immune response to infection. This novel, proprietary drug is designed to prevent complement-mediated inflammation and endothelial damage while leaving intact the respective functions of the other pathways of innate immunity.

Hematopoietic Stem Cell Transplant-Associated Thrombotic Microangiopathy (TA-TMA)

  • Narsoplimab has been granted FDA Breakthrough Therapy designation in patients who have high-risk TA-TMA, as well as Orphan Drug designation for the prevention of complement-mediated TMAs and for the treatment of TA-TMA. In the European Union, narsoplimab has been designated an Orphan Medicinal Product for treatment in hematopoietic stem cell transplantation.
  • The 61% response rate and 68% 100-day survival seen with narsoplimab-treated TA-TMA patients in the pivotal clinical trial represent an approximately three-fold improvement when compared to an untreated age- and disease status-matched cohort from a systematic literature review.1,2
  • Omeros is pursuing approval in the US and in Europe for narsoplimab to treat TA-TMA.

Narsoplimab OMS721 MASP-2 antibody inhibitor, breakthrough therapy and orphan drug for HSCT-TMA
View our pipeline to learn about ongoing narsoplimab clinical studies

1Khaled SK, Claes K, Goh YT, et al. Narsoplimab, a mannan-binding lectin-associated protease-2 inhibitor, for the treatment of adult hematopoietic stem-cell transplantation–associated thrombotic microangiopathy. J Clin Oncol. 2022; 40(22):2447-2457.
2Whitaker S, Nangia N, Ng E, Sotolongo S, Pullman W. Systematic literature review of the natural history of hematopoietic stem cell transplant-associated thrombotic microangiopathy in adults. Presented at: 48th Annual Meeting of the European Society for Blood and Marrow Transplantation; March 19-23, 2022.