Cohort A (Prophylactic treatment) for Hemophilia A

This is a prospective, observational, multi-center longitudinal cohort study to describe the real-world effectiveness, safety and treatment usage of efanesoctocog alfa in patients with hemophilia A treated per standard of care in the US and Japan. Patients will be enrolled in the study after the introduction of efanesoctocog alfa in the hemophilia treatment landscape in each study country. Decision to initiate treatment with commercially available efanesoctocog alfa will be made by the treating physician independently from the decision to include patients in the study. No study medication is provided. The data related to efanesoctocog alfa effectiveness, safety and usage will be collected prospectively during routine visits (expected annual/semi-annual visits) for up to 5 years following enrollment /treatment initiation.