With 5 Nbs currently in clinical trials, and the recent approval of caplacizumab (CabliviTM), a bivalent VHH targeting von Willebrand factor (vWF), by the EMA in October 2018 and the FDA in February 2019 for thrombotic thrombocytopenic purpura and thrombosis, this excitement is not surprising [17]. Here, VWF is linked to thrombotic thrombocytopenic purpura.