Hemophilia APhase 4NCT06145373
A Study to Test a Medicine (Fitusiran) for Preventing Bleeds in People With Severe Hemophilia Who Previously Received Preventive Treatment With Emicizumab
A Phase 4 study testing Fitusiran (SAR439774), Clotting factor concentrates (CFC) or bypassing agents (BPA) and Antithrombin concentrate (ATIIIC) in people with Hemophilia A, run by Sanofi at 3 sites in 2 countries.
Trial 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. Read more about this study
- Who is it for?
- Ages 12 years and older, men only
- Conditions the study is for
- Hemophilia A
- What is being tested?
- Fitusiran (SAR439774), Clotting factor concentrates (CFC) or bypassing agents (BPA) and Antithrombin concentrate (ATIIIC)
- Type of treatment
- Injection or infusion
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 20 participants
- Where
- 3 sitesin 2 countries
- Study dates
- 1 Mar 2024to 30 Jan 2030
- Phase
- Phase 4
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 12 years and older
- Men only
- No healthy volunteers
- Child, Adult, Older adult
Who may be able to join
- 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.
Who cannot join
- 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
Show all 14Show fewer
- 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.
Trial locations and contacts
3 sites in 2 countries. Contact the study team or a site near you to ask about taking part.
Trial Transparency email recommended (Toll free for US & Canada) contact
3 sites in 2 countries
United States2 sites, 2 recruiting
- Recruiting
Southern Specialty Research- Site Number : 8400011
Flowood, Mississippi, 39232
- Recruiting
Children's Hospital Los Angeles- Site Number : 8400005
Los Angeles, California, 90027
Taiwan1 site, 1 recruiting
- Recruiting
Investigational Site Number : 1580001
Taipei, 100
About this study
Official title: An Open-label, Single-arm Treatment Study to Investigate the Safety and Tolerability of Switching From Emicizumab to Fitusiran Prophylaxis in Male Participants Aged ≥12 Years of Age With Severe Hemophilia A, With or Without Inhibitors
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.
Read more
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
- Being tested
- Fitusiran (SAR439774), Clotting factor concentrates (CFC) or bypassing agents (BPA), Antithrombin concentrate (ATIIIC), Emicizumab
- Medical subject headings
- Hemophilia A
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Fitusiran (SAR439774)Drug
Also called SAR439774, Qfitlia®
Pharmaceutical form:Solution for injection-Route of administration:Subcutaneous (SC) injection
Clotting factor concentrates (CFC) or bypassing agents (BPA)Biological
Pharmaceutical form: Solution for injection-Route of administration: Intravenous (IV) injection
Antithrombin concentrate (ATIIIC)Biological
Pharmaceutical form:Solution for injection-Route of administration:Intravenous (IV) injection
EmicizumabBiological
Pharmaceutical form:Solution for injection-Route of administration:SC injection
| Study group | Role | What they receive |
|---|---|---|
| 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. Receives: Drug: Fitusiran (SAR439774); Biological: Clotting factor concentrates (CFC) or bypassing agents (BPA); Biological: Antithrombin concentrate (ATIIIC); Biological: Emicizumab |
What is being measured
The primary outcome is the main question the study is designed to answer.
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
Measured: From Day 1 up to Month 4
Secondary outcomes (13)
The peak thrombin generation (TG) - pre fitusiran treatment
Central laboratory assessments (peak TG) will be reported for pre-fitusiran period
Measured: From Month -2 up to Day 1
The peak TG during fitusiran treatment
Central laboratory assessments (peak TG) will be reported for fitusiran treatment period
Measured: From Day 1 up to Month 4
The antithrombin (AT) levels during pre-fitusiran treatment
Central laboratory assessments (AT) will be reported for pre-fitusiran treatment period
Measured: From Month -2 up to Day 1
The AT levels during fitusiran prophylaxis
Central laboratory assessments (AT) will be reported for fitusiran treatment
Measured: From Day 1 up to Month 4
Emicizumab concentrations in plasma
Emicizumab concentrations in plasma will be reported
Measured: Up to Month 4 of fitusiran treatment
Number of participants with AEs from Day 1 to Month 18 of fitusiran treatment
Incidence, severity, and seriousness of AEs will be reported
Measured: From Day 1 up to Month 18
Change in participants' overall treatment satisfaction during the fitusiran treatment period assessed via the Treatment Satisfaction Questionnaire for Medication (TSQM-9) domain scores
The three domains of effectiveness, convenience, and global satisfaction will be reported
Measured: From approximately Month -2 to Month 19 [end of study (EoS) visit]
Participants' treatment preferences (via the Preference Questionnaire)
The Preference questionnaire Data will be reported
Measured: At Month 12
Change in adult participants' pain intensity during the fitusiran treatment period over time
The PROMIS (Patient-Reported Outcomes Measurement Information System) Pain Intensity 3a v2.0 consists of three items measuring the worst, average, and current intensity of pain with a recall period of 7 days. Each question has five response options ranging from one ('no pain') to five ('very severe').
Adult participants (age ≥ 18 years) will self-complete the PROMIS Pain Intensity 3a v2.0 questionnaire.
Measured: From approximately Month - 2 to Month 19 (EoS) visit
Change in adolescent participants' pain intensity during the fitusiran treatment period over time
The PROMIS Pediatric Numeric Rating Scale v.1.0 - Pain Intensity 1a consists of one item measuring the average intensity of pain with a recall period of 7 days. The question has ten response options ranging from one ('no pain') to ten ('worst pain').
Adolescent participants (age ≥12 years and <17 years) will self-complete the PROMIS Pediatric Pain Intensity 1a v.1.0.
Measured: From approximately Month - 2 to Month 19 (EoS) visit
Change in participants' physical functioning and physical activity during the fitusiran treatment period (via the International Physical Activity Questionnaire [IPAQ]) over time
Participants' physical functioning and physical activity data during the fitusiran treatment period will be collected via the International Physical Activity Questionnaire and reported
Measured: From approximately Month - 2 to Month 19 (EoS) visit
Change in participants' joint health (via the Hemophilia Joint Health Score [HJHS]) during the fitusiran treatment period over time
HJHS during the fitusiran treatment period will be reported
Measured: From approximately Month - 2 to Month 19 (EoS) visit
Annualized Bleeding Rate (ABR) while receiving fitusiran prophylaxis
The frequency of treated bleeding episodes will be reported
Measured: From Month 4 up to Month 18 (14-month extension period)
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted24 Nov 2023
- Study start1 Mar 2024
- Primary completion28 May 2028 (estimated)
- Study completion30 Jan 2030 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Hemophilia AStudies of the same condition, open and under way.
- More trials run by SanofiThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 4
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Enrolment
- 20 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Sanofi
- Sponsor type
- Industry (pharma, biotech, devices)
- Responsible party
- Sponsor
- Investigators
- Clinical Sciences & Operations, Study director, Sanofi
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06145373
- Sponsor's protocol ID
- SFY17741
- Other IDs
- 2022-502414-84, U1111-1280-7227
- Status last verified
- Sep 2026
- First submitted
- 17 Nov 2023
- Last updated
- 23 Sep 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- Yes: Qualified researchers may request access to patient level data and related study documents including the clinical study report, study protocol with any amendments, blank case report form, statistical analysis plan, and dataset specifications. Patient level data will be anonymized and study documents will be redacted to protect the privacy of trial participants. Further details on Sanofi's data sharing criteria, eligible studies, and process for requesting access can be found at: https://vivli.org
Study at a glance
From the registry record, last updated by the sponsor on 23 Sep 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- An Open-label, Single-arm Treatment Study to Investigate the Safety and Tolerability of Switching From Emicizumab to Fitusiran Prophylaxis in Male Participants Aged ≥12 Years of Age With Severe Hemophilia A, With or Without Inhibitors
- ClinicalTrials.gov ID
- NCT06145373
- Acronym / sponsor ID
- SFY17741
- Conditions
- Hemophilia A
- Phase
- Phase 4
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 20 participants (estimated)
- Lead sponsor
- SanofiIndustry (pharma, biotech, devices)
- Study start
- 1 Mar 2024 (actual)
- Primary completion
- 28 May 2028 (estimated)
- Study completion
- 30 Jan 2030 (estimated)
- First posted
- 24 Nov 2023 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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.
Study design
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| fitusiran | Experimental | Drug: Fitusiran (SAR439774), Biological: Clotting factor concentrates (CFC) or bypassing agents (BPA), Biological: Antithrombin concentrate (ATIIIC), Biological: EmicizumabThe 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. |
Who may qualify
- Ages
- 12 years and older
- Sex
- Male only
- Healthy volunteers
- Not accepted
- Age groups
- Child, Adult, Older adult
Key inclusion criteria (7 listed)
- 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.
- 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.
Key exclusion criteria (14 listed)
- 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
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Fitusiran (SAR439774)Also: SAR439774, Qfitlia®Pharmaceutical form:Solution for injection-Route of administration:Subcutaneous (SC) injection | Drug | fitusiran |
| Clotting factor concentrates (CFC) or bypassing agents (BPA)Pharmaceutical form: Solution for injection-Route of administration: Intravenous (IV) injection | Biological | fitusiran |
| Antithrombin concentrate (ATIIIC)Pharmaceutical form:Solution for injection-Route of administration:Intravenous (IV) injection | Biological | fitusiran |
| EmicizumabPharmaceutical form:Solution for injection-Route of administration:SC injection | Biological | fitusiran |
Primary outcome
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
13 secondary outcomes
The peak thrombin generation (TG) - pre fitusiran treatment
Time frame: From Month -2 up to Day 1
The peak TG during fitusiran treatment
Time frame: From Day 1 up to Month 4
The antithrombin (AT) levels during pre-fitusiran treatment
Time frame: From Month -2 up to Day 1
The AT levels during fitusiran prophylaxis
Time frame: From Day 1 up to Month 4
Emicizumab concentrations in plasma
Time frame: Up to Month 4 of fitusiran treatment
Number of participants with AEs from Day 1 to Month 18 of fitusiran treatment
Time frame: From Day 1 up to Month 18
Change in participants' overall treatment satisfaction during the fitusiran treatment period assessed via the Treatment Satisfaction Questionnaire for Medication (TSQM-9) domain scores
Time frame: From approximately Month -2 to Month 19 [end of study (EoS) visit]
Participants' treatment preferences (via the Preference Questionnaire)
Time frame: At Month 12
Change in adult participants' pain intensity during the fitusiran treatment period over time
Time frame: From approximately Month - 2 to Month 19 (EoS) visit
Change in adolescent participants' pain intensity during the fitusiran treatment period over time
Time frame: From approximately Month - 2 to Month 19 (EoS) visit
Change in participants' physical functioning and physical activity during the fitusiran treatment period (via the International Physical Activity Questionnaire [IPAQ]) over time
Time frame: From approximately Month - 2 to Month 19 (EoS) visit
Change in participants' joint health (via the Hemophilia Joint Health Score [HJHS]) during the fitusiran treatment period over time
Time frame: From approximately Month - 2 to Month 19 (EoS) visit
Annualized Bleeding Rate (ABR) while receiving fitusiran prophylaxis
Time frame: From Month 4 up to Month 18 (14-month extension period)
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 23 Sep 2026.
- SFY17741 Plain Language Results SummariesLink provided by the sponsor.
- For EU sites click here and navigate to 'Locations and contact points'Link provided by the sponsor.
- Individual participant dataSharing planned: Yes. Qualified researchers may request access to patient level data and related study documents including the clinical study report, study protocol with any amendments, blank case report form, statistical analysis plan, and dataset specifications. Patient level data will be anonymized and study documents will be redacted to protect the privacy of trial participants. Further details on Sanofi's data sharing criteria, eligible studies, and process for requesting access can be found at: https://vivli.org
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Trial Transparency email recommended (Toll free for US & Canada) contact
Clinical Sciences & Operations study director
Sanofi
3 sites in 2 countries: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 4 study testing Fitusiran (SAR439774), Clotting factor concentrates (CFC) or bypassing agents (BPA) and Antithrombin concentrate (ATIIIC) in people with Hemophilia A, run by Sanofi at 3 sites in 2 countries.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 7 inclusion and 14 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 23 Sep 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 3 sites in United States, Taiwan. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 4 studies take place after a treatment is approved, to learn more about its long-term benefits and risks in everyday use.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Trial Transparency email recommended (Toll free for US & Canada) (800-633-1610 ext. option 6, Contact-US@sanofi.com), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Number of participants with Adverse events (AEs) during the fitusiran treatment (time frame: From Day 1 up to Month 4). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 23 Sep 2026.