BACKGROUND: Thrombotic thrombocytopenic purpura (TTP) is a potentially fatal blood disorder, resulting from severe deficiency of plasma ADAMTS13 activity. Current treatment for immune-mediated TTP includes daily therapeutic plasma exchange (TPE), plus caplacizumab and immunosuppressives. For hereditary TTP, resulting from mutations of ADAMTS13, plasma infusion or recombinant ADAMTS13 is the treatment of choice. However, there are still unmet needs for an effective alternative therapy for TTP. OBJECTIVE: The present study aims to evaluate therapeutic efficacy of a novel humanized antibody Fab fragment against platelet glycoprotein Ibα (CA1001) in a murine model of TTP. METHODS: Platelet agglutination profiles, microfluidic shear-based assay, and intravital microscopy thrombosis model, as well as lysine histone-induced murine "TTP-like" model were employed. RESULTS: CA1001 exhibits potent inhibition of botrocetin-induced murine platelet agglutination in a dose and time-dependent manner. CA1001 also significantly inhibits shear-dependent adhesion and aggregation of murine platelets to endothelial von Willebrand factor (VWF) released from calcium ionophore activated cremaster venules in Adamts13 CONCLUSIONS: CA1001 can effectively inhibit VWF-platelet interaction and thrombus formation under various (patho)physiological conditions. Thus, CA1001 may be a potential candidate for further development as a novel therapeutic for immune-mediated and hereditary TTP and perhaps for other inflammatory thrombotic disorders such as ischemic stroke.