Actively Recruiting
An Open-label, Single-arm Study to Assess Safety and Tolerability of Switching From Emicizumab to Fitusiran Prophylaxis in Males 12 Years and Older With Severe Hemophilia A
Led by Sanofi · Updated on 2026-06-02
20
Participants Needed
2
Research Sites
87 weeks
Total Duration
On this page
AI-Summary
What this Trial Is About
Researchers are evaluating the safety and tolerability of switching male participants aged 12 years and older with severe hemophilia A, with or without inhibitors, from emicizumab prophylaxis to fitusiran prophylaxis. This Phase 4 exploratory study focuses on participants who were previously receiving emicizumab and aims to monitor adverse events and other health outcomes during and after the switch. Participants will first undergo a screening period of about 2 months, followed by a pre-fitusiran treatment period of approximately 2 months where they continue with intravenous clotting factor concentrates or bypassing agents as needed. Then, participants will receive subcutaneous fitusiran prophylaxis either once every two months or monthly for up to 18 months. After the fitusiran treatment, there is a follow-up period of about 6 months to monitor antithrombin activity levels until they return to at least 60%. During the study, intravenous antithrombin concentrate may be given if judged necessary by the investigator, and bleeding events will be managed with intravenous clotting factors or bypassing agents. Throughout the study, participants will have regular clinic visits scheduled monthly or every two months during the fitusiran treatment period. Researchers will assess adverse events, thrombin generation, antithrombin levels, emicizumab concentrations, treatment satisfaction, pain intensity, physical activity, joint health, and annualized bleeding rate. Antithrombin activity will be closely monitored during follow-up until recovery. The study duration can be up to approximately 28 months, including all periods from screening to follow-up.
CONDITIONS
Brief Title
A Study to Test a Medicine (Fitusiran) for Preventing Bleeds in People With Severe Hemophilia Who Previously Received Preventive Treatment With Emicizumab
Who Can Participate
Eligibility Criteria
You may qualify if you...
- Male participants aged 12 years or older at the time of informed consent
- Diagnosed with severe congenital hemophilia A (factor VIII level less than 1%) confirmed by laboratory measurement or medical record
- Inhibitor titer of 0.6 BU/mL or higher at screening, or lower titers with specific medical record evidence
- Currently receiving the full labeled dose of emicizumab prophylaxis regardless of inhibitor status
- Signed informed consent and agree to comply with study requirements
You will not qualify if you...
- Known coexisting bleeding disorders other than hemophilia A
- History of antiphospholipid antibody syndrome
- History of arterial or venous blood clots, atrial fibrillation, significant heart valve disease, heart attack, angina, stroke, or transient ischemic attack, except thrombosis linked to venous access
- Clinically significant liver disease
- Current or prior participation in fitusiran or gene therapy trials
- Antithrombin activity less than 60% at screening
- Coexisting thrombophilic disorder or positive Hepatitis C antibody without negative viral load and no cirrhosis
- Presence of acute hepatitis A or E
- Acute or chronic hepatitis B infection
- HIV positive with CD4 count below 200 cells/microliter
- Reduced kidney function
AI-Screening
AI-Powered Screening
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Your Study Journey
Duration - 2 to 4 weeks
Participants are screened for eligibility to participate in the trial.
1 visit (in-person)
Duration - Approximately 2 months (from Month -2 until Day 1)
Participants receive on-demand or prophylactic intravenous clotting factor concentrates (CFCs) or bypassing agents (BPAs) during the transition period before starting fitusiran.
Visits as needed for treatment and assessments
Duration - Up to 18 months
Participants receive subcutaneous fitusiran prophylaxis once every 2 months or once monthly from Day 1 until Month 18. Intravenous antithrombin concentrate (ATIIIC) may be given based on investigator judgment. Bleeding events are treated with intravenous CFCs or BPAs as needed.
Regular visits for fitusiran administration and monitoring during treatment period
Duration - Variable, until recovery
Participants are followed until antithrombin activity levels recover to at least 60% as measured by the central laboratory.
Visits as needed for monitoring antithrombin levels
Trial Site Locations
Total: 2 locations
1
Children's Hospital Los Angeles- Site Number : 8400005
Los Angeles, California, United States, 90027
Actively Recruiting
2
Investigational Site Number : 1580001
Taipei, Podlaskie, Taiwan, 100
Actively Recruiting
Research Team
T
Trial Transparency email recommended (Toll free for US & Canada)
How is the study designed?
Study Type
INTERVENTIONAL
Masking
NONE
Allocation
NA
Model
SINGLE_GROUP
Primary Purpose
TREATMENT
Number of Arms
1
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