A Study to Test a Medicine (Fitusiran) for Preventing Bleeds in People With Severe Hemophilia Who Previously Received Preventive Treatment With Emicizumab

Inclusion Criteria:

• Male participants must be ≥18 years of age inclusive, at the time of signing theinformed consent
• Diagnosis of severe congenital hemophilia A (FVIII < 1%) as evidenced by a centrallaboratory measurement at screening or documented medical record evidence.
• Inhibitor titer of ≥0.6 BU/mL at Screening, or
• Inhibitor titer of <0.6 BU/mL at Screening with medical record evidence of 2consecutive titers ≥0.6 BU/mL, or
• Inhibitor titer of <0.6 BU/mL at Screening with medical record evidence ofanamnestic response.
• Participants who are currently on the full labeled dose of emicizumab prophylaxis,irrespective of inhibitor/non-inhibitor status.
• Capable of giving signed informed consent which includes compliance with therequirements and restrictions listed in the informed consent form (ICF) and in thisprotocol.

Exclusion Criteria: Participants are excluded from the study if any of the followingcriteria apply:

• Known coexisting bleeding disorders
• History of antiphospholipid antibody syndrome.
• History of arterial or venous thromboembolism, atrial fibrillation, significantvalvular disease, myocardial infarction, angina, transient ischemic attack, or stroke.Participants who have experienced thrombosis associated with indwelling venous accessmay be enrolled.
• Presence of clinically significant liver disease
• Current or prior participation in a fitusiran trial
• Current or prior participation in a gene therapy trial
• AT activity <60% at Screening, as determined by central laboratory measurement
• Coexisting thrombophilic disorder - Hepatitis C virus antibody positive, exceptparticipants who have negative Hepatitis C viral load and no evidence of cirrhosis
• Presence of acute hepatitis, ie, hepatitis A, hepatitis E.
• Presence of acute or chronic hepatitis B infection
• Known to be HIV positive with CD4 count <200 cells/μL.
• Reduced renal function The above information is not intended to contain all considerations relevant to a patient'spotential participation in a clinical trial.