Caplacizumab is a humanized, bivalent nanobody (single-domain antibody fragment) used for the treatment of acquired thrombotic thrombocytopenic purpura (aTTP). It is marketed under the brand name Cablivi and represents the first-in-class therapeutic specifically approved for this rare, life-threatening thrombotic microangiopathy. Caplacizumab is administered subcutaneously and works by rapidly inhibiting the formation of pathological platelet clumps within small blood vessels. It is used as an adjunct to plasma exchange (the standard therapy) and immunosuppression, significantly reducing the time to platelet count normalization, the risk of recurrent thrombotic events, and mortality associated with aTTP.