The FDA granted approval to Omeros’s complement‑system drug Yartemlea to treat a severe, potentially fatal complication following hematopoietic stem cell transplantation. The action, reported by MedCity News, marks the first regulatory clearance for a therapy targeting this post‑transplant syndrome. Regulators evaluated clinical data showing clinical benefit in the high‑mortality population and cleared the drug for defined post‑transplant indications. Complement inhibitors block parts of the innate immune cascade that can trigger widespread inflammation and organ damage; this approval establishes a validated therapeutic pathway for managing complement‑mediated post‑transplant injury. The decision is likely to change inpatient transplant protocols and could prompt payers to reassess coverage for similar agents. Clinicians and transplant centers will monitor real‑world safety as the drug moves into broader use.