The U.S. Food and Drug Administration approved Yartemlea (narsoplimab) from Omeros as the first treatment for hematopoietic stem cell transplant‑associated thrombotic microangiopathy (TA‑TMA), the agency said. The approval establishes a regulatory precedent for an often‑fatal post‑transplant complication with no previously approved therapies. Approval provides clinicians an evidence‑based option for TA‑TMA and gives Omeros a commercial foothold in a specialized post‑transplant niche. Payers and transplant centers will now evaluate adoption, diagnosis criteria, and real‑world outcomes for the newly approved agent.