Study to Test the Safety of an Investigational Drug Given Repeatedly to Adult Men With Severe Hemophilia

Inclusion Criteria: * Participants with hemophilia A and FVIII activity \<1% or hemophilia B with FIX activity \<2% * Participants must be currently without inhibitors or with low titer inhibitors (inhibitor titer \< 5 Bethesda units) who are receiving current on demand treatment with any FVIII or FIX (recombinant or plasma-derived; modified or unmodified) Exclusion Criteria: * History or at risk of developing diseases related to venous thromboembolic events (e.g., pulmonary embolism, deep vein thrombosis or thrombophlebitis) * History of any other clinically relevant coagulation disorder (particularly disseminated intravascular coagulopathy or combined FVIII/Factor V deficiency) or platelet disorder * History or at risk of developing cardiac, coronary and/or arterial peripheral atherosclerotic disease and/or arterial thromboembolic events, particularly myocardial infarction, cerebrovascular accident, stroke, transient ischemic attack, congestive heart failure, angina pectoris, treatment for angina pectoris or uncontrolled hypertension * History or at risk for thrombotic microangiopathy