Fitusiran Prophylaxis in Male Pediatric Subjects Aged 1 to Less Than 12 Years With Hemophilia A or B

Prior treatment

• Use of emicizumab (Hemlibra®) within 6 months prior to screening

Other illness

• Known co-existing bleeding disorders other than hemophilia A or B
• Co-existing thrombophilic disorder
• Clinically significant liver disease
• Active Hepatitis C virus infection
• Acute or chronic Hepatitis B virus infection
• Acute Hepatitis A or hepatitis E infection
• History of arterial or venous thromboembolism, unrelated to an indwelling venous access
• History of multiple drug allergies or history of allergic reaction to an oligonucleotide or N-Acetylgalactosamine (GalNAc)
• Subjects with central or peripheral indwelling catheters, with history of venous access complications leading to hospitalization and/or systemic anticoagulation therapy.
• History of intolerance to subcutaneous (SC) injection(s)
• Any other conditions or comorbidities that would make the patient unsuitable for enrollment or could interfere with participation in or completion of the study, per Investigator judgment
  • The above information is not intended to contain all considerations relevant to a patient's potential participation in a clinical trial.

Lab values

• HIV positive with a CD4 count of \<400 cells/μL

Other

• Participants are excluded from the study if any of the following criteria apply:
• Antithrombin (AT) activity \<60% at Screening
• Inadequate renal function

• Male, aged 1 to \<12 years at the time of enrollment.
• Severe hemophilia A or B (Factor VIII (FVIII) \<1% or Factor IX (FIX) ≤2%)
• Participants must have inhibitory antibodies to FVIII or FIX and must meet one of the following Nijmegen-modified Bethesda assay results criteria:
  • Inhibitor titer of ≥0.6 BU/mL at screening, OR
  • Inhibitor titer of \<0.6 BU/mL at screening with medical record evidence of 2 consecutive titers ≥0.6 BU/mL, OR
  • Inhibitor titer of \<0.6 BU/mL at screening with medical record evidence of 1 inhibitor titer ≥0.6 BU/mL and a history of anamnestic response or severe allergic reaction (anaphylaxis or nephrotic syndrome)
• Adequate peripheral venous access, as determined by the Investigator, to allow the blood draws required by the study protocol
• Weight requirements at the time of enrollment: 8 to \<45 kg
• Willing and able to comply with the study requirements and to provide signed written informed consent obtained from parent(s)/legal guardian (hereinafter the "parent") and written or oral assent obtained from participant, per local and national requirements