Safety and Efficacy of Iptacopan in Patients With High-Risk Transplantation-Associated Thrombotic Microangiopathy

The goal of this clinical trial is to evaluate the efficacy and safety of Iptacopan as a second-line treatment for high-risk hematopoietic stem cell transplantation-associated thrombotic microangiopathy (TA-TMA). Iptacopan is a selective oral small-molecule complement factor B inhibitor. It acts by inhibiting factor B, blocking the formation of C3 convertase, reducing C3b deposition, thereby suppressing C5 convertase (C3bBbC3b) and ultimately decreasing the formation of the membrane attack complex (MAC), which is expected to mitigate endothelial damage in TA-TMA pathology. The main questions this study aims to answer are: * Does Iptacopan improve 6-month overall survival in high-risk TA-TMA patients? * What adverse events do participants experience while taking Iptacopan? * Does Iptacopan provide hematological response and organ function recovery in TA-TMA patients? In this prospective, multicenter, open-label, single-arm Phase II study, all participants will receive Iptacopan treatment. The primary endpoint of this study is the 6-month overall survival rate from TA-TMA diagnosis. Secondary endpoints include safety evaluation, hematological response, and organ function recovery. During the study, participants will: * Receive Iptacopan treatment according to protocol * Undergo regular assessments for safety and efficacy monitoring * Be followed for up to 24 months post-treatment initiation