Catalyst Biosciences is a clinical-stage biopharmaceutical company focused on developing medicines to address hematology indications, including the treatment of hemophilia. Co. is focusing its product development efforts in the fields of hemostasis (the process that regulates bleeding). Co.'s principal product candidate is marzeptacog alfa (activated), a Factor VIIa variant. Marzeptacog alfa (activated) is being developed for the prophylactic treatment of individuals with hemophilia A and B with inhibitors. Co.'s second product candidate is CB 2679d/ISU304, a subcutaneously dosed Factor IX drug for the prophylactic treatment of individuals with hemophilia B.