FDA Approves First Drug to Treat Serious Complication of Stem Cell Transplant

https://www.accessdata.fda.gov/drugsatfda_docs/label/2025/761152Orig1s000lbl.pdf?utm_medium=email&utm_source=govdelivery FDA Approves First Drug to Treat Serious Complication of Stem Cell Transplant Treatment approved for hematopoietic stem cell transplant-associated thrombotic microangiopathy Action Last week, the U.S. Food and Drug Administration (FDA) approved Yartemlea (narsoplimab-wuug) injection to treat adults and children 2 years and older with hematopoietic stem cell transplant-associated thrombotic microangiopathy (TA-TMA) as the first approved treatment option for TA-TMA. Disease or Condition Hematopoietic stem cell transplant-associated thrombotic microangiopathy (TA-TMA) is a serious and life-threatening complication of hematopoietic stem cell transplant in which tiny blood clots form in the small blood vessels. This can lead to organ damage, including damage to the kidneys, cardiovascular system, and gastrointestinal tract. Data Supporting Yartemlea The efficacy of Yartemlea was assessed in a single-arm, open-label study (TA-TMA Study) of 28 patients, with additional data from 19 patients (6 pediatric patients and 13 adult patients) enrolled in an expanded access program. In the TA-TMA Study, patients either received Yartemlea 4 mg/kg or 370 mg intravenously once weekly. In the TA-TMA Study, the primary efficacy assessment was the TMA response, defined as improvement in both laboratory TMA markers (lactate dehydrogenase and platelet counts) and either organ function improvement or no need for transfusions. The TA-TMA response was achieved in 61% of patients. In the expanded access program, TA-TMA response was achieved in 67% of pediatric patients and 69% of adult patients. Safety Information The most common side effects are viral infections, sepsis, hemorrhage, diarrhea, vomiting, nausea, neutropenia (low number of neutrophils, a type of white blood cell), fever, fatigue, and low potassium. Patients should also be monitored for signs of serious infections. Designations Yartemlea received Priority Review, Breakthrough Therapy Designation, and Orphan Drug Designation for this indication.