NCT06145373 · Sanofi
A Study to Test a Medicine (Fitusiran) for Preventing Bleeds in People With Severe Hemophilia Who Previously Received Preventive Treatment With Emicizumab
What this study is about
This is an exploratory, single group, Phase 4, study to assess treatment with fitusiran prophylaxis after switching from emicizumab prophylaxis. This study aims to evaluate the safety and how well patients handle the treatment of switching to fitusiran after a transition period from the last dose of emicizumab.
View original scientific description
This is an exploratory, single group, Phase 4, study to assess treatment with fitusiran prophylaxis after switching from emicizumab prophylaxis. This study aims to evaluate the safety and tolerability of switching to fitusiran after a transition period from the last dose of emicizumab. The study will be conducted in male participants with severe hemophilia A, with or without inhibitors, aged ≥12 years, who were previously receiving emicizumab prophylaxis. Study details include: * The study duration will be up to approximately 28 months: * There will be an approximately 2-month screening period. * There will be an approximately 2-month period before fitusiran treatment starts (pre-fitusiran treatment period) * The fitusiran treatment duration will be up to 18-months (fitusiran treatment period) * The antithrombin (AT) follow-up (FU) period will be approximately 6 months after the last dose of fitusiran (during which the AT activity level will be monitored at approximately monthly intervals following the final fitusiran dose until AT activity levels return to at least 60%). * The study site visits are scheduled at monthly/ every 2 months intervals of 28 days (4 weeks) / 56 days (8 weeks), respectively, during the fitusiran treatment period.
Interventions
DRUG
Fitusiran (SAR439774)
Pharmaceutical form:Solution for injection-Route of administration:Subcutaneous (SC) injection
BIOLOGICAL
Clotting factor concentrates (CFC) or bypassing agents (BPA)
Pharmaceutical form: Solution for injection-Route of administration: Intravenous (IV) injection
BIOLOGICAL
Antithrombin concentrate (ATIIIC)
Pharmaceutical form:Solution for injection-Route of administration:Intravenous (IV) injection
BIOLOGICAL
Emicizumab
Pharmaceutical form:Solution for injection-Route of administration:SC injection
Primary outcome measures
Number of participants with Adverse events (AEs) during the fitusiran treatment
Time frame: From Day 1 up to Month 4
Incidence, severity, and seriousness, of AEs occurred during fitusiran treatment period will be reported
Who can participate
This study lists these criteria on ClinicalTrials.gov. A study coordinator reviews eligibility during screening — this page does not determine whether you qualify.
Inclusion criteria
- Male participants must be ≥12 years of age inclusive, at the time of signing the informed consent
- Diagnosis of severe congenital hemophilia A (FVIII \< 1%) as evidenced by a central laboratory 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 2 consecutive titers ≥0.6 BU/mL, or
- Inhibitor titer of \<0.6 BU/mL at Screening with medical record evidence of anamnestic response.
- Participants who are currently on the full labeled dose of emicizumab prophylaxis, irrespective of inhibitor/non-inhibitor status.
- Signed informed consent/assent which includes compliance with the requirements and restrictions listed in the informed consent form (ICF) and in this protocol.
Exclusion criteria
- Participants are excluded from the study if any of the following criteria apply:
- Known coexisting bleeding disorders
- History of antiphospholipid antibody syndrome.
- History of arterial or venous thromboembolism, atrial fibrillation, significant valvular disease, myocardial infarction, angina, transient ischemic attack, or stroke. Participants who have experienced thrombosis associated with indwelling venous access may 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, except participants 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's potential participation in a clinical trial.
Where
- Los Angeles, California
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Frequently asked questions
What is a clinical trial?
A clinical trial is a research study that tests new medical treatments, drugs, devices, or procedures to determine their safety and effectiveness. Trials are carefully designed and monitored to protect participants while advancing medical knowledge.
Is it safe to participate?
Clinical trials follow strict safety guidelines and ethical standards. Trials must be reviewed and approved, and participants are closely monitored by medical professionals throughout the study. You can withdraw at any time if you choose.
Will I be compensated?
Many clinical trials offer compensation for your time, travel expenses, and inconvenience. The specific compensation varies by study and will be discussed during the screening process. All study-related medical care is typically provided at no cost to participants.
Will I receive a placebo instead of treatment?
When effective treatment exists, participants typically receive either the standard treatment plus the study intervention, or the standard treatment plus placebo. You would not be denied effective care. Placebos are primarily used when no proven treatment is available, or in addition to standard care. Your trial consent form will clearly explain what treatments you may receive.
Can I leave a trial if I change my mind?
Absolutely. Participation in clinical trials is completely voluntary. You have the right to withdraw from the study at any time, for any reason, without penalty or loss of benefits to which you are otherwise entitled.
How long does a clinical trial last?
Trial duration varies widely depending on the study design and purpose. Some trials last just a few weeks, while others may continue for months or years. The study coordinator will provide specific timeline information during your screening call.
Data: ClinicalTrials.gov · synced Jun 2, 2026 · Source of record for eligibility and locations