Use of Narsoplimab for Eculizumab-Refractory Adult Transplant-Associated Thrombotic Microangiopathy (TA-TMA)

Abstract Transplant Associated thrombotic microangiopathy (TA-TMA) is fatal complication associated with hematopoietic stem cell transplant. Endothelial dysfunction and compliment activation causes consumptive thrombocytopenia with intravascular hemolysis, resulting in end organ damage especially to the kidneys and lungs. There are no FDA approved agents for TA-TMA. Eculizumab is the most commonly used agent to treat TA-TMA. Patients who do not respond to Eculizumab have a dismal prognosis with reported mortality up to 80%. Narsoplimab, a mannan-binding lectin-associated serine protease-2 (MASP-2) inhibitor has shown to treat TA-TMA by inhibiting the lectin pathway of the compliment cascade. We report the first adult case with successful management of eculizumab refractory TA- TMA with Narsoplimab. This case highlights the importance of early recognition of TA-TMA and the need to switch therapy to other compliment inhibitors if resistance to Eculizumab is noted.