Study to Provide Continued Access to Treatment for Patients Completing a Previous Trial With Efanesoctocog Alfa

Inclusion Criteria:

• Capable of giving signed informed consent. Parents or legally designatedrepresentatives' consent is required for patients who are below 18 years of age orunable to give consent. Patients who are below 18 years of age may provide assent inaddition to the parents'/legally designated representatives' consent, ifappropriate.

• Must have completed one of the required parent studies: Sobi.BIVV001-001,Sobi.BIVV001-003, or LTS16294, and be receiving a clinical benefit from theefanesoctocog alfa treatment, as judged by the Investigator.

• Willingness and ability of patient or their parent or legally designatedrepresentative to complete training in the use of the study patient diary and tocomplete the diary throughout the study.

Exclusion Criteria:

• Positive inhibitor result (assessed by central laboratory), defined as ≥0.6 Bethesdaunits (BU)/mL, at Baseline Visit.

• Ongoing or planned participation in any interventional clinical study at BaselineVisit.

• Patient not suitable for participation, whatever the reason, as judged by theInvestigator, including medical or clinical conditions, or patients potentially atrisk of noncompliance to study procedures.