The United States Food and Drug Administration (FDA) has approved a new drug developed by Omeros Corporation for the treatment of a dangerous complication that can occur after stem cell transplants, making it the first therapy authorised specifically for this condition in both adults and children aged two years and older.
The drug, marketed as Yartemlea and known chemically as narsoplimab‑wuug, is indicated for transplant‑associated thrombotic microangiopathy (TA‑TMA), a serious and potentially life‑threatening disorder that arises when damaged blood vessels and an overactive immune response after stem cell transplantation lead to inflammation and the formation of tiny clots that can damage organs such as the kidneys. This condition has historically lacked an approved targeted treatment option.
The FDA had initially declined approval of the drug in 2021 due to insufficient evidence of a clear treatment effect, but Omeros provided additional clinical data, including results from a 28‑patient trial in which the therapy improved survival in 61 percent of high‑risk TA‑TMA patients when used as a first‑line treatment.
Yartemlea is a monoclonal antibody that blocks the MASP‑2 protein involved in the immune system’s lectin pathway, which contributes to the pathogenesis of TA‑TMA.
The treatment is expected to be available on the market by January 2026, and a decision on marketing authorisation from the European Medicines Agency is anticipated in mid‑2026. The approval represents a significant advancement in care for transplant recipients facing this severe complication.
