Indirectly, fitusiran allows to achieve higher thrombin values, which can restore homeostatic balance in patients with hemophilia B. Fitusiran therapy can be compared to balancing between a state of hypercoagulability (decreased level of AT and impaired blood coagulation (reduced level of factor IX in hemophilia B), which, if the right proportions are achieved, may become a universal solution for many patients. The gene discussed is F9; the disease is thrombophilia.