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

NCT06145373 | Recruiting Phase 4 DMC FDA Drug

• 3 other identifiers: SFY177412022-502414-84U1111-1280-7227
• Study Type: interventional
• Target: 20
• Locations: 2 countries
• Sites: 2

Brief Summary

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.

Conditions

Hemophilia A

Outcome Measures

Primary Outcomes (1)

• Number of participants with Adverse events (AEs) during the fitusiran treatment

  Incidence, severity, and seriousness, of AEs occurred during fitusiran treatment period will be reported

  From Day 1 up to Month 4

Secondary Outcomes (13)

• The peak thrombin generation (TG) - pre fitusiran treatment

  From Month -2 up to Day 1

• The peak TG during fitusiran treatment

  From Day 1 up to Month 4

• The antithrombin (AT) levels during pre-fitusiran treatment

  From Month -2 up to Day 1

• The AT levels during fitusiran prophylaxis

  From Day 1 up to Month 4

• Emicizumab concentrations in plasma

  Up to Month 4 of fitusiran treatment

Study Arms (1)

fitusiran

EXPERIMENTAL

The pre-fitusiran treatment period is defined as the transition period up to the first fitusiran administration. Participants will receive on demand or prophylactic treatment with intravenous clotting factor concentrates (IV CFCs) or bypassing agents (BPAs) from Month-2 until Day 1. Fitusiran treatment period: Participants will receive subcutaneous (SC) fitusiran prophylaxis once every 2 months (Q2M) or once monthly (QM) from Day 1 until Month18. Participants may receive IV antithrombin concentrate (ATIIIC) upon investigator's judgement. AT FU period: Participants will be followed up until AT activity levels recover to at least 60% (per central laboratory). In case of bleeding events participants will receive IV CFCs or BPAs. Participants may receive IV ATIIIC upon investigator's judgement.

Drug: Fitusiran (SAR439774); Biological: Clotting factor concentrates (CFC) or bypassing agents (BPA); Biological: Antithrombin concentrate (ATIIIC); Biological: Emicizumab

Interventions

Fitusiran (SAR439774) DRUG

Pharmaceutical form:Solution for injection-Route of administration:Subcutaneous (SC) injection

Also known as: SAR439774, Qfitlia®

fitusiran

Clotting factor concentrates (CFC) or bypassing agents (BPA) BIOLOGICAL

Pharmaceutical form: Solution for injection-Route of administration: Intravenous (IV) injection

fitusiran

Antithrombin concentrate (ATIIIC) BIOLOGICAL

Pharmaceutical form:Solution for injection-Route of administration:Intravenous (IV) injection

fitusiran

Emicizumab BIOLOGICAL

Pharmaceutical form:Solution for injection-Route of administration:SC injection

fitusiran

Eligibility Criteria

• Age: 12 Years+
• Sex: male
• Healthy Volunteers: No
• Age Groups: Child (0-17), Adult (18-64), Older Adult (65+)

You may qualify if:

• 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.

You may not qualify if:

• 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.

Sponsors & Collaborators

• Sanofi: lead

Study Sites (2)

Children's Hospital Los Angeles- Site Number : 8400005

Los Angeles, California, 90027, United States

RECRUITING

Investigational Site Number : 1580001

Taipei, Podlaskie, 10041, Taiwan

RECRUITING

Related Links

• SFY17741 Plain Language Results Summaries

MeSH Terms

Conditions

Hemophilia A

Interventions

fitusiran; emicizumab

Condition Hierarchy (Ancestors)

Blood Coagulation Disorders, Inherited; Blood Coagulation Disorders; Hematologic Diseases; Hemic and Lymphatic Diseases; Coagulation Protein Disorders; Hemorrhagic Disorders; Genetic Diseases, Inborn; Congenital, Hereditary, and Neonatal Diseases and Abnormalities

Study Officials

• Clinical Sciences & Operations

  Sanofi

  STUDY DIRECTOR

Central Study Contacts

Trial Transparency email recommended (Toll free for US & Canada)

CONTACT

800-633-1610; Contact-US@sanofi.com

Study Design

• Study Type: interventional
• Phase: phase 4
• Allocation: NA
• Masking: NONE
• Purpose: TREATMENT
• Intervention Model: SINGLE GROUP
• Sponsor Type: INDUSTRY
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: November 17, 2023
• First Posted: November 24, 2023
• Study Start: March 1, 2024
• Primary Completion (Estimated): September 19, 2026
• Study Completion (Estimated): November 30, 2029
• Last Updated: September 30, 2025

Record last verified: 2025-09

Data Sharing

• IPD Sharing: Will share

Locations

TW (1); US (1)