Assembly of the FIXa-FX enzyme-substrate complex leads to formation of activated factor Xa (FXa), which is a key mediator of the coagulation pathway (Borensztajn et al., 2008) and the bsAbs are therefore relevant for treatment of hemophilia A (Shima et al., 2016; Mahlangu et al., 2018; Lauritzen et al., 2022). The gene discussed is F10; the disease is hemophilia A.