Emicizumab and the Clinical Coagulation Laboratory

Emicizumab, a novel therapeutic agent for patients with hemophilia A (HA), is a humanized, asymmetric, bispeci fi c, IgG4 monoclonal antibody designed to mimic the function of activated factor VIII (FVIII). Clinical studies have demonstrated its utility in the successful treatment of HA patients with and without anti-FVIII alloantibodies. The conventional methods currently used for monitoring management of HA will be discussed along with why they may be inappropriate for patients receiving emicizumab. Alternative methods (ie, global testing) will be presented and discussed in the context of emicizumab. With the increasing availability of treatment with emicizumab, it is important the clinical laboratory understands the mechanism, interaction with conventional coagulation assays, and alternative methods for its monitoring. This review describes and discusses the di ff erent assays used to measure the e ff ectiveness of emicizumab as well as monitor FVIII activity in patients with HA.