First-in-Human and Proof-of-Mechanism Study of ARC19499 Administered to Hemophilia Patients

Inclusion Criteria: Adult male patients ≥18 to ≤75 years of age. * Hemophilia of any type or severity. * Patients who are negative for hepatitis B surface antigen (HBsAg), and human immunodeficiency virus (HIV) I and II antibody tests at screening. * Male patients who, with their partners, are willing to use 2 effective, methods of contraception (i.e., for both self and partner) throughout the study and for at least 3 months after discontinuation of study drug treatment. * All patients must be capable of understanding and complying with the protocol and must have signed the informed consent document. Exclusion Criteria: * Female patients; * If on a prophylactic coagulation factor concentrate regimen, inability or unwillingness to discontinue prophylaxis during participation in this study. * Existence of other co-existing bleeding disorder (e.g., von Willebrand Disease). * Medical history of venous or arterial thromboembolism. * Scheduled for elective surgical procedure during the conduct of this study. * Use of an investigational drug within 30 days of study entry. * Transaminase values \> 3 x upper limit of normal (ULN) at time of screening. * Haemoglobin \<12.0 g/dL. * Participants who, in the opinion of the Investigator, have a significant infection or known inflammatory process on screening. * Participants who have a clinically relevant history or presence of respiratory, gastrointestinal, renal, hepatic, lymphatic, neurological, cardiovascular, psychiatric, musculoskeletal, genitourinary, immunological, dermatological, connective tissue diseases or disorders. * Any medical condition the investigator believes would place the patient at increased risk as a result of participation in the study e.g. history of thromboembolic disease or stroke. * Any medication the investigator considers may increase the risk of adverse effects during the study.