The goal of this TO is to develop a bispecific monoclonal antibody that will bind canine coagulation FIX and FX for preventing bleeding in hemophilia A dogs with and without inhibitory antibodies to canine FVIII. This bispecific monoclonal antibody will be made by modifying the human product (emicizumab or HemLibra™) that currently does not work in canine plasma. The task order proposal from the UNC represents clinically significant work to develop a bispecific monoclonal antibody that will bind canine coagulation FIX and FX for preventing bleeding in hemophilia A dogs with and without inhibitory antibodies to canine FVIII. The development of this antibody will enable studies of inhibitor formation, prevention and ablation by greatly increasing the survival rate of hemophilia A dogs with inhibitors. It will also provide a critically needed animal model system for investigating incompletely understood thrombotic complications that have occurred with emicizumab use in humans and for addressing a series of clinical questions that have arisen since the FDA granted drug approval. The proposal includes milestones and a timeline with defined success criteria. The UNC site has an excellent environment and the team is experienced. Clear timelines, milestones and established procedures are provided.