Study terminated due to business and strategic decision.

The purpose of the study is to evaluate the efficacy, safety, tolerability and pharmacokinetic (PK) profile of prophylactic SerpinPC in participants with hemophilia

Inclusion Criteria:

• Male participants greater than or equal to (>=) 12 and less than or equal to (<=) 65 years of age at the time of informed consent
• Completed participation in a sponsored SerpinPC hemophilia clinical trial and, in the opinion of the investigator, was compliant with the study including compliance with diary entries.
• Capable of providing written informed consent (adolescent assent and parent/guardian consent when appropriate) for participation

Exclusion Criteria:

• Previous deep vein thrombosis and pulmonary embolism, myocardial infarction, or embolic stroke
• Participation in another interventional clinical trial, except for SerpinPC trials
• Any other significant conditions or comorbidities that, in the opinion of the investigator, would make the subject unsuitable for enrolment or could interfere with participation in or completion of the study
• Treatment with anticoagulant or antiplatelet drugs