narsoplimab

Narsoplimab is a fully human **monoclonal antibody** developed by Omeros that inhibits **mannan-binding lectin-associated serine protease-2** and thereby blocks activation of the **lectin pathway of complement** while sparing the classical and alternative complement pathways. The drug has been developed primarily for **hematopoietic stem cell transplant-associated thrombotic microangiopathy** and has also been studied in **IgA nephropathy**, where phase 2 data suggested reductions in proteinuria and stable kidney function in some patients, but the phase 3 ARTEMIS-IGAN trial was discontinued after failing its primary endpoint. Omeros has also pursued regulatory review in TA-TMA, including a resubmitted U.S. BLA with a late-September 2025 PDUFA target date, and used Lonza as its commercial manufacturing partner.

Brand names

Yartemlea

Other names

Narsoplimab