Bleeding Events and Safety Outcomes in Patients with Hemophilia a with Inhibitors: A Prospective, Multicenter, Non-Interventional Study

Introduction: Coagulation factor VIII (FVIII) deficiency in hemophilia A (HA) patients (pts) results in spontaneous bleeding events, secondary arthropathy and diminished quality of life (QoL). FVIII replacement agents, the current standard of care, may require several infusions to treat bleeding events and infusions 2-3 times a week are needed for prevention of bleeding events due to relatively short half-lives. A major challenge of current therapies is development of anti-FVIII alloantibodies (inhibitors), which occur in 15-30% of HA pts, diminish effectiveness of FVIII replacement and are associated with significant morbidity and reduced QoL. Options for pts with inhibitors are limited. Bypassing agents to prevent/treat bleeding events, and immune tolerance induction to eliminate inhibitors, require frequent dosing, are not available in all countries, and have suboptimal efficacy. Thus, a high unmet need exists for safe, more effective and less burdensome options for pts with inhibitors. Emicizumab (ACE910), a bispecific monoclonal antibody in development for the management of HA, binds to FIXa and FX to mimic FVIII cofactor function and may be able to address current treatment needs.