A Phase 4 interventional study of Fitusiran (SAR439774) and Clotting factor concentrates (CFC) or bypassing agents (BPA) in Hemophilia A, sponsored by Sanofi. Recruiting at 3 sites in 2 countries. Open to male participants aged 12 Years and older. Per ClinicalTrials.gov, last updated 2026-09-23.
Sponsored by Sanofi · Phase 4, Interventional, and Treatment
Among 10 studies testing fitusiran in Hemophilia A — 2 open to participants now, 3 under way, 2 of them phase 3. fitusiran · Hemophilia A.
Among the 10 studies testing fitusiran in Hemophilia A, this one is the 10th largest by planned enrollment, is the only one that started in 2024, is the only one in phase 4, and was the 9th registered.
844 studies on the registry are indexed under Hemophilia A; 136 are open to participants now.
Browse Hemophilia A studies →2 of the 10 studies testing fitusiran in Hemophilia A are open now, in 12 countries. Recruiting first, the newest first:
Sanofi · Sites in United States, Belgium, Brazil and 9 more countries
Ages 1–11 · Men only
By country, each count listing its studies:
fitusiran: first FDA approval 2025 (QFITLIA). What it is approved for, and how studies give it, is on its page →
Of the 86 Hemophilia A studies recruiting now, 51 (59%) set no upper age limit and 30 (35%) stop at 75 or younger; 54 take children under 18; 10 take healthy volunteers.
This study: 12 Years and older · male · no healthy volunteers.
The full table on the hub →This tab as a report to print or save as PDF → With an account.
10 studies; the count open now beside each. This study's row is marked.
A study in two phases is counted once above. Listed by phase, each with its combined phases: Phase 1 2 · Phase 2 2 · Phase 3 7 · Phase 4 1
First in 2014; this study’s year is marked. 1 started in 2024.
This study's planned enrollment of 20 is below the median of 30 across 499 interventional studies indexed under Hemophilia A.
Median enrollment 70 across the 10 interventional studies. Of the 7 that completed or were terminated, 4 (57%) have results posted.
This tab as a report to print or save as PDF → With an account.
10 of 10 have an industry lead sponsor. The 2 most frequent:
Sanofi is the lead sponsor of 1,558 studies on the registry; 90 are open to participants now.
Of its 205 completed or terminated interventional studies of FDA-regulated products, 123 (60%) have results posted.
29 studies in Hemophilia A by Sanofi: 4 open now, 8 under way, 3 of them phase 3. Of 21 finished, 14 (67%) have results posted.
Among the 29 studies in Hemophilia A by Sanofi, this one is the 19th largest by planned enrollment of the 24 interventional ones that give a count, is one of 3 that started in 2024, is one of 3 in phase 4, and was the 24th registered.
Sanofi’s Hemophilia A studies by the year they started, since 2009.
1 of the studies testing fitusiran in Hemophilia A that are under way reach primary completion within a year, 1 of them phase 3. Phase 3 first, then by date:
| Study | Primary completion |
|---|---|
| NCT05662319Phase 3SanofiA Study to Test a Medicine (Fitusiran) Injected Under the Skin for Preventing Bleeding Episodes in Male Adolescent or Adult Participants With Severe Hemophilia | 2027-03-25 |
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Among the 10 studies testing fitusiran in Hemophilia A, from their registry updates:
Among Sanofi’s 29 in Hemophilia A:
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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:
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Diagnosis of severe congenital hemophilia A (FVIII \< 1%) as evidenced by a central laboratory measurement at screening or documented medical record evidence.
Exclusion Criteria:
Participants are excluded from the study if any of the following criteria apply:
The above information is not intended to contain all considerations relevant to a patient's potential participation in a clinical trial.
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
A “mini-stroke”: temporary stroke-like symptoms caused by reduced blood flow to part of the brain, spinal cord or eye, without signs of a new stroke on a scan.
Stroke symptoms need emergency care at once, even if they go away.
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
Hepatitis C is a virus that infects the liver. An HCV antibody test can stay positive after an infection has cleared (and is occasionally positive without one); an HCV RNA test shows whether the virus is there now.
After treatment, hepatitis C counts as cured when HCV RNA is still undetectable 12 weeks or more after the treatment ended. Studies often accept people cured this way.
Hepatitis B is a virus that infects the liver. These are separate tests: HBsAg positive usually means a current infection (a recent vaccination can briefly cause it too); total anti-HBc (HBcAb) positive means an infection now or in the past; HBV DNA measures how much virus is in the blood.
Some studies accept a past infection if HBV DNA is undetectable, sometimes with antiviral medicine during the study. Check what this study allows.
The human immunodeficiency virus, which weakens the immune system.
Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.
The number of CD4 cells, a type of white blood cell, in a given amount of blood. It is used to follow how well the immune system is doing in HIV.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
TIA (transient ischaemic attack)
A “mini-stroke”: temporary stroke-like symptoms caused by reduced blood flow to part of the brain, spinal cord or eye, without signs of a new stroke on a scan.
Stroke symptoms need emergency care at once, even if they go away.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Clinically significant
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hepatitis C tests
Hepatitis C is a virus that infects the liver. An HCV antibody test can stay positive after an infection has cleared (and is occasionally positive without one); an HCV RNA test shows whether the virus is there now.
After treatment, hepatitis C counts as cured when HCV RNA is still undetectable 12 weeks or more after the treatment ended. Studies often accept people cured this way.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hepatitis B tests
Hepatitis B is a virus that infects the liver. These are separate tests: HBsAg positive usually means a current infection (a recent vaccination can briefly cause it too); total anti-HBc (HBcAb) positive means an infection now or in the past; HBV DNA measures how much virus is in the blood.
Some studies accept a past infection if HBV DNA is undetectable, sometimes with antiviral medicine during the study. Check what this study allows.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
HIV
The human immunodeficiency virus, which weakens the immune system.
Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
CD4 count
The number of CD4 cells, a type of white blood cell, in a given amount of blood. It is used to follow how well the immune system is doing in HIV.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
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
Pharmaceutical form:Solution for injection-Route of administration:Subcutaneous (SC) injection
Also known as: SAR439774, Qfitlia®
Pharmaceutical form: Solution for injection-Route of administration: Intravenous (IV) injection
Pharmaceutical form:Solution for injection-Route of administration:Intravenous (IV) injection
Pharmaceutical form:Solution for injection-Route of administration:SC injection
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
Time frame: From Day 1 up to Month 4
The peak thrombin generation (TG) - pre fitusiran treatment
Central laboratory assessments (peak TG) will be reported for pre-fitusiran period
Time frame: 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
Time frame: 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
Time frame: From Month -2 up to Day 1
The AT levels during fitusiran prophylaxis
Central laboratory assessments (AT) will be reported for fitusiran treatment
Time frame: From Day 1 up to Month 4
Emicizumab concentrations in plasma
Emicizumab concentrations in plasma will be reported
Time frame: 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
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
The three domains of effectiveness, convenience, and global satisfaction will be reported
Time frame: 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
Time frame: 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.
Time frame: 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.
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
Participants' physical functioning and physical activity data during the fitusiran treatment period will be collected via the International Physical Activity Questionnaire and reported
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
HJHS during the fitusiran treatment period will be reported
Time frame: 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
Time frame: From Month 4 up to Month 18 (14-month extension period)
Plan to share: 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
Started Mar 2024 (actual). Primary completion is estimated for May 2028, 50 months after the start.
Of 39 phase 4 interventional studies under Hemophilia A, half reached primary completion within 31 months of starting (the median), counting those still running; a quarter within 13 and three quarters within 112. This study's planned 50 months is above that.
How these figures are worked out, and which studies are left out of them.
Eligibility is decided by the study team. Share this record with your doctor or contact the team directly.
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Studies of the drugs tested here: Fitusiran · Emicizumab