Acquired or immune-mediated thrombotic thrombocytopenic purpura (aTTP) is a life-threatening auto-immune disorder caused by a functional deficiency of the von Willebrand factor-cleaving protease ADAMTS13, leading to thrombotic microangiopathy. The introduction of plasma-exchange has reduced mortality from over 90% to 10–20%. However, over the last two decades the treatment outcomes have not changed substantially. Caplacizumab, a humanised nanobody directed to the A1 domain of VWF, inhibits this lethal thrombotic cascade and is therefore essential for symptom control and prevention of irreversible end-organ damage. Both TITAN and HERCULES trials demonstrated that treatment with caplacizumab significantly reduced mean duration of hospitalisation and number of days of plasma-exchange. Moreover, no deaths were observed in caplacizumab-treated patients. Therefore, we can state that caplacizumab has changed the treatment paradigm of aTTP.

(BELG J HEMATOL 2020;11(3):120–7)