The U.S. Food and Drug Administration approved Omeros Corp.’s Yartemlea (narsoplimab) for treatment of hematopoietic stem cell transplant–associated thrombotic microangiopathy (TA‑TMA), marking the first approved therapy for this life‑threatening transplant complication. The biologics license application met a Dec. 26 PDUFA date and secured FDA clearance based on available clinical evidence that the monoclonal antibody targeting mannan-binding lectin-associated serine protease‑2 improves outcomes in affected patients. Approval creates a new standard-of-care option for transplant centers managing TA‑TMA and opens a commercial pathway for Omeros in a high unmet‑need niche. The decision will influence care protocols in hematopoietic stem cell transplant programs and is likely to spur follow‑on clinical and payer activity around diagnosis and reimbursement for the condition.