Severe Hemophilia Non-Interventional Study

The primary objective of this study is to obtain prospective baseline documentation of annualized bleeding rates (ABRs) and treatment under standard-of-care (SOC) therapy among participants with hemophilia A or B. Participants in the study may be eligible to enroll in future planned interventional studies to be conducted by Sponsor.

Inclusion Criteria:Male participants greater than or equal to (>=) 12 and less than or equal to (<=) 65 years of ageWho are capable of providing written informed consent (adolescent assent and parental/guardian consent when appropriate) for participation after reading the information and consent form and having the opportunity to discuss the study with the Investigator or their designeeWith historically documented severe HemA (defined as factor VIII [FVIII] less than (<) 0.01 International Units per milliliter (IU/mL) [<1 percent {%}]), with or without inhibitors, or moderately severe to severe HemB (defined as factor IX [FIX] <=0.02 IU/mL [<=2%]) without inhibitors. Participants must be currently included in a prophylactic treatment program or if undergoing an on-demand treatment regimen must have had >=6 documented acute bleeding episodes (spontaneous or traumatic) that required coagulation factor infusion during the 6 months before enrollment OR: Historically documented HemB (defined as FIX <=0.05 IU/mL [<=5%]) with inhibitors with a historical or ongoing high titer inhibitor [>=5 Bethesda Units/mL] based on medical records or laboratory reports) and an ABR of >=6 in the 6 months before enrollmentWho are able to use a diary to document bleeding events and associated treatmentExclusion Criteria:With known thrombophiliaWith body weight greater than (>)150 kilogram (kg) or body mass index >40With known current inadequate hematologic function (eg, platelet count <100,000 per microliter [/mcL] and/or hemoglobin level <10 grams per deciliter [g/dL], <100 g/L), hepatic function (that is, total bilirubin >1.5*upper limit of normal [ULN] [excluding Gilbert syndrome], aspartate transferase and/or alanine aminotransferase levels >3*ULN; clinical signs or known laboratory or radiographic evidence consistent with cirrhosis of the liver) or renal function (that is, serum creatinine >2*ULN; based on medical records or available laboratory reports)With previous deep vein thrombosis and pulmonary embolism, myocardial infarction, or strokeWith history of intolerance to subcutaneous injectionsWith known current uncontrolled hypertension (systolic blood pressure >160 millimeter of mercury (mm Hg); diastolic blood pressure >100 mm Hg; based on medical records)With active cancer or requires therapy for cancer, except for basal cell carcinomaWith concurrent participation in an interventional clinical trialWith current or planned use of emicizumabWith prior, ongoing, or planned treatment with gene therapy for hemophiliaWith history of or other evidence of recent alcohol or drug abuse as determined by the Investigator or their designee (in the 12 months before enrollment)With known Human Immunodeficiency Virus (HIV) infection with CD4 count (or T-cell count) of <200 cells/mcL within 24 weeks before enrollmentWith current or planned treatment with anticoagulant or antiplatelet drugsWith any other significant conditions or comorbidities that, in the opinion of the Investigator or their designee, would make the participant unsuitable for enrollment