Treatment of transplantation-associated thrombotic microangiopathy with iptacopan: two cases report.

Transplantation-associated thrombotic microangiopathy (TA-TMA) is a life-threatening complication of hematopoietic stem cell transplantation (HSCT). With mortality rates up to 90% without timely treatment, effective management remains a challenge. Complement dysregulation plays a central role in TA-TMA pathogenesis. We reported two TA-TMA cases successfully treated with iptacopan, a factor B inhibitor targeting the alternative pathway. A 40-year-old male with early T-cell precursor acute lymphoblastic leukemia developed early-onset TA-TMA post-HSCT, and a 41-year-old female with acute myeloid leukemia arising from previous myelodysplastic syndrome developed delayed-onset TA-TMA after allo-HSCT. Iptacopan administration led to significant clinical and biochemical recovery in both two patients. These two cases highlight iptacopan's potential as an effective therapy for TA-TMA.