Hemophilia A is a blood coagulation disorder caused by deficient or dysfunctional clotting factor VIII (FVIII) leading to incomplete haemostasis. Patients with severe Hemophilia A are predisposed to recurrent bleeding episodes (BEs) in joints and soft tissues that culminate in debiltating arthropathy and long-term morbidity. Prophylaxis with plasma-derived or recombinant FVIII concentrates effectively restores FVIII levels in patients with Hemophilia A, and significantly reduces the risk of bleeding. A critical concern for patients receiving FVIII replacement therapy is the development of neutralising antibodies (inhibitors) against the treatment. Inhibitors develop in up to 40% of patients with severe Hemophilia A when first exposed to FVIII treatment, typically within the first 20-30 exposure days (EDs) although a residual risk remains until after 75 EDs. Inhibitors preclude the use of FVIII replacement therapy for prevention and treatment of bleeding. Eradication of inhibitors therefore remains an important objective for Hemophilia A patients with inhibitors. Immune tolerance induction (ITI) therapy is the only clinically proven strategy for inhibitor eradication, and at least one attempt should be offered to patients with inhibitors. However, while ITI is well-studied and has a 60- 80% success rate, treatment regimens can be expensive and burdensome to patients. There are limited data on the use of different dose regimen of FVIII ITI in China. The INITIATE Study was designed to observe treatment strategies in patients with hemophilia A with inhibitors, with a focus on evaluating the safety and effectiveness of different dose regimens of ITI. The INITIATE Study includes multiple groups to explore factors that may affect ITI outcomes, and to explore the effects of different treatment methods on patient ITI biomarkers (genomics, transcriptomics, proteins (antibodies).