The FDA has approved narsoplimab (Yartemlea) as the first drug to treat thrombotic microangiopathy associated with hematopoietic stem cell transplantation (TA-TMA) in adults and children 2 years and older, according to manufacturer Omeros.[5] Narsoplimab is a MASP-2 inhibitor that targets the lectin branch of complement; this pathway is thought to be important in the pathogenesis of TA-TMA.Omeros originally filed a Biologics License Application (BLA) and previously received a Complete Response Letter (CRL) from the FDA, after which the company submitted supplemental data and a resubmission of the application.[2][5] Included in the resubmission are primary analyses comparing overall survival of patients treated with narsoplimab to an external control group and analyses from the expanded access program; these analyses showed clinically meaningful and statistically significant survival improvements with narsoplimab treatment.[2][5] The FDA granted narsoplimab Breakthrough Therapy and Orphan Drug statuses to support a more expeditious review and regulatory process.Prior to approval, TA-TMA was treated predominantly with plasmapheresis exchange, dialysis, and transfusions; thus, narsoplimab would have been the first specific approved treatment for this complication.[1][5