Long-term Safety and Efficacy Study of Fitusiran in Patients With Hemophilia A or B, With or Without Inhibitory Antibodies to Factor VIII or IX (ATLAS-OLE)

The estimated total time on study for each participant is up to 56 months which consists of a screening period of up to 60 days, an open label treatment period of up to 48 months and a follow up period of up to 6-month after the last dose of fitusiran. The duration of the treatment period and overall that of study participation, may exceed the intervals stated above for patient enrolled in the lower-dose cohort, to ensure a minimum of 18-month administration at this dosing regimen

Inclusion criteria :

• Participant must be at least 12 years of age inclusive, at the time of signing the informed consent
• Participants with severe hemophilia A or B who have completed a Phase 3 fitusiran clinical trial
• Male
• Capable of giving signed informed consent which includes compliance with the requirements and restrictions listed in the informed consent form (ICF) and in the protocol. In countries where legal age of majority is above 18 years, a specific ICF must also be signed by the participant's legally authorized representative

Exclusion criteria:

• Completion of a surgical procedure within 14 days prior to screening, or currently receiving additional factor concentrate or BPA infusion for postoperative hemostasis
• Current participation in immune tolerance induction treatment (ITI)
• Current use of factor concentrates or bypassing agents (BPAs) as regularly administered prophylaxis designed to prevent spontaneous bleeding episodes except for participants requiring factor concentrates or BPAs prophylaxis during the study dosing pause period
• Use of compounds other than factor concentrates or BPAs for hemophilia treatment
• Current or prior participation in a gene therapy trial
• Alanine aminotransferase (ALT) and/or Aspartate aminotransferase (AST) >1.5 × upper limit of normal reference range (ULN) for patients who are naïve to fitusiran at study start; ALT and/or AST > 5 x ULN for patients who were in the fitusiran arm in the parent study
• Additional exclusions for participants not currently participating in a fitusiran trial at the time of enrollment in the lower dose cohort:
  • Clinically significant liver disease
  • History of arterial or venous thromboembolism

        The above information is not intended to contain all considerations relevant to a patient's
        potential participation in a clinical trial.