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HemophiliaPhase 3ATLAS-NEONCT05662319

A Study to Test a Medicine (Fitusiran) Injected Under the Skin for Preventing Bleeding Episodes in Male Adolescent or Adult Participants With Severe Hemophilia

A Phase 3 study testing Fitusiran, Clotting factor concentrates (CFC) or bypassing agents (BPA) and Antithrombin concentrate (ATIIIC) in people with Hemophilia, run by Sanofi at 50 sites in 17 countries.

Active, not recruiting

Under way, not looking for participants. Everyone needed has enrolled. The study is still running.

Official record
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Trial summary

This is a multicenter, multinational, open-label, one-way cross-over, Phase 3, single-arm study for treatment of hemophilia. The purpose of this study is to measure the frequency of treated bleeding episodes with fitusiran in male adult and adolescent (≥12 years old) participants with hemophilia A or B, with or… Read more about this study

Who is it for?
Ages 12 years and older, men only
Conditions the study is for
Hemophilia
What is being tested?
Fitusiran, 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
91 participants
Where
50 sitesin 17 countries
Study dates
1 Feb 2023to 25 Jan 2029
Phase
Phase 3
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

  • Diagnosis of severe congenital hemophilia A or B (FVIII <1% or FIX level ≤2%) as evidenced by a central laboratory measurement at screening or documented medical record evidence.
  • For participants currently not on prophylaxis (CFC or BPA on-demand): A minimum of 4 bleeding episodes requiring BPA (inhibitor participants) or CFC (non-inhibitor participants) treatment within the last 6 months prior to screening.
  • Willing and able to comply with the study requirements and to provide written informed consent and assent in the case of participants under the age of legal consent, per local and national requirements

Who cannot join

  • Known co-existing bleeding disorders other than congenital hemophilia A or B
  • History of arterial or venous thromboembolism, not associated with an indwelling venous access
  • History of intolerance to SC injection(s).
  • Current participation in immune tolerance induction therapy (ITI)
  • Prior gene therapy
  • Current or prior participation in a fitusiran trial
Show all 15Show fewer
  • Current or prior participation in a gene therapy trial
  • Received an investigational drug or device within 30 days prior to the screening visit or within 5 half-lives of the investigational drug (or device) prior to the screening visit, whichever is longer
  • Presence of clinically significant liver disease AT activity <60% at Screening
  • Co-existing 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

50 sites in 17 countries.

50 sites in 17 countries

United States8 sites
  • University Hospitals of Cleveland Site Number : 8400001

    Cleveland, Ohio, 44106

  • Children's Medical Center Dallas- Site Number : 8400018

    Dallas, Texas, 75235

  • Hackensack University Site Number : 8400009

    Hackensack, New Jersey, 07601

  • Gulf States Hemophilia and Thrombophilia Center- Site Number : 8400002

    Houston, Texas, 77030

  • M Health Fairview University of Minnesota Medical Center - West Bank- Site Number : 8400016

    Minneapolis, Minnesota, 55454

  • Northwell Health Hemostasis and Thrombosis Center Site Number : 8400015

    New Hyde Park, New York, 11040

  • Center for Inherited Blood Disorders (CIBD) Site Number : 8400012

    Orange, California, 92868-4306

  • UPMC Children's Hospital of Pittsburgh-4401 Penn Ave Site Number : 8400017

    Pittsburgh, Pennsylvania, 15224-1334

Other trials in United States

India5 sites
  • Investigational Site Number : 3560004

    Bangalore, 560 034

  • Investigational Site Number : 3560007

    Bhubaneswar, 751019

  • Investigational Site Number : 3560001

    Pune-411011, 411 011

  • Investigational Site Number : 3560006

    Punjab, 141008

  • Investigational Site Number : 3560003

    Vellore, 632004

Other trials in India

Turkey (Türkiye)4 sites
  • Investigational Site Number : 7920002

    Adana, 01130

  • Investigational Site Number : 7920004

    Akdeniz, 07059

  • Investigational Site Number : 7920001

    Çapa, 34390

  • Investigational Site Number : 7920003

    Izmir, TR-35100

Other trials in Turkey (Türkiye)

Canada3 sites
  • Investigational Site Number : 1240001

    Hamilton, Ontario, L8N 3Z5

  • Investigational Site Number : 1240002

    Hamilton, Ontario, L8N 3Z5

  • Investigational Site Number : 1240004

    Toronto, Ontario, M5G 1X8

Other trials in Canada

China3 sites
  • Investigational Site Number : 1560003

    Beijing, 100045

  • Investigational Site Number : 1560001

    Guangzhou, 510515

  • Investigational Site Number : 1560002

    Jinan, 250013

Other trials in China

France3 sites
  • Investigational Site Number : 2500003

    Le Kremlin-Bicêtre, 94275

  • Investigational Site Number : 2500002

    Lille, 59037

  • Investigational Site Number : 2500001

    Paris, 75015

Other trials in France

Japan3 sites
  • Investigational Site Number : 3920001

    Kashihara-shi, Nara, 634-8522

  • Investigational Site Number : 3920003

    Nagoya, Aichi-ken, 4668560

  • Investigational Site Number : 3920002

    Saitama-shi, Saitama, 330-8777

Other trials in Japan

Mexico3 sites
  • Investigational Site Number : 4840004

    Chihuahua City, 31000

  • Investigational Site Number : 4840002

    Monterrey, Nuevo León, 64460

  • Investigational Site Number : 4840001

    Veracruz, 91900

Other trials in Mexico

Poland3 sites
  • Investigational Site Number : 6160002

    Krakow, Lesser Poland Voivodeship, 30-688

  • Investigational Site Number : 6160004

    Lodz, Lódzkie, 93-510

  • Investigational Site Number : 6160001

    Warsaw, Masovian Voivodeship, 02-776

Other trials in Poland

Germany2 sites
  • Investigational Site Number : 2760001

    Berlin, 10249

  • Investigational Site Number : 2760002

    Hamburg, 20246

Other trials in Germany

Greece2 sites
  • Investigational Site Number : 3000001

    Athens, 115 27

  • Investigational Site Number : 3000002

    Athens, 11527

Other trials in Greece

Italy2 sites
  • Investigational Site Number : 3800001

    Milan, 20122

  • Investigational Site Number : 3800003

    Rozzano, Milano, 20089

Other trials in Italy

South Africa2 sites
  • Investigational Site Number : 7100003

    Johannesburg, 1501

  • Investigational Site Number : 7100001

    Parktown, 2193

Other trials in South Africa

South Korea2 sites
  • Investigational Site Number : 4100001

    Seoul, Seoul-teukbyeolsi, 03722

  • Investigational Site Number : 4100002

    Seoul, Seoul-teukbyeolsi, 05278

Other trials in South Korea

Spain2 sites
  • Investigational Site Number : 7240002

    A Coruña, A Coruña [La Coruña], 15006

  • Investigational Site Number : 7240003

    Zaragoza, 50009

Other trials in Spain

Taiwan2 sites
  • Investigational Site Number : 1580001

    Taipei, 100

  • Investigational Site Number : 1580003

    Taipei, 11031

Other trials in Taiwan

Saudi Arabia1 site
  • Investigational Site Number : 6820002

    Jeddah, 21423

Other trials in Saudi Arabia

About this study

Official title: A Phase 3, Single-arm, Multicenter, Multinational, Open-label, One-way Crossover Study to Investigate the Efficacy and Safety of Fitusiran Prophylaxis in Male Participants Aged ≥ 12 Years With Severe Hemophilia A or B With or Without Inhibitory Antibodies to Factor VIII or IX

This is a multicenter, multinational, open-label, one-way cross-over, Phase 3, single-arm study for treatment of hemophilia.

The purpose of this study is to measure the frequency of treated bleeding episodes with fitusiran in male adult and adolescent (≥12 years old) participants with hemophilia A or B, with or without inhibitory antibodies to factor VIII or IX who have switched from their prior standard of care treatment.

Read more

The total study duration will be up to approximately 50 months (200 weeks, 1 study month is equivalent to 4 weeks) and will include:

  • A screening period up to approximately 60 days,
  • A standard of care (SOC) period of approximately 6 study months (24 weeks),
  • A fitusiran treatment period of approximately 36 study months (144 weeks),
  • An antithrombin (AT) follow-up period of approximately 6 study months (24 weeks) but may be shorter or longer depending on individual participants AT recovery.

The frequency for telephone visits will be approximately every 2 weeks. For site visits the frequency will be approximately every 8 weeks during the SOC period and approximately every 4 weeks during the fitusiran treatment period. If applicable and if allowed by local regulation, home and/or remote visits may be conducted during the study

Conditions
Hemophilia
Being tested
Fitusiran, Clotting factor concentrates (CFC) or bypassing agents (BPA), Antithrombin concentrate (ATIIIC)
Medical subject headings
Hemophilia A

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • FitusiranDrug

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

  • Clotting factor concentrates (CFC) or bypassing agents (BPA)Drug

    • Coagulation factor VIII (ATC code: B02BD02)
    • Coagulation factor IX (ATC code: B02BD04)
    • Coagulation factor VIIa (ATC code: B02BD08)
    • Factor VIII inhibitor bypassing activity (ATC code: B02BD03)

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

  • Antithrombin concentrate (ATIIIC)Drug

    Antithrombin III (ATC code: B01AB02) Pharmaceutical form: Solution for infusion Route of administration: Intravenous (IV)

Study groups in NCT05662319
Study groupRoleWhat they receive
All participantsExperimentalIn standard of care (SOC) period, participants will receive on-demand or prophylactic treatment with clotting factor concentrates (CFCs) or bypassing agents (BPAs) for 6 months (from Day -168 to Day -1). In fitusiran treatment period, participants will receive subcutaneous fitusiran prophylaxis once every other month (Q2M) or once monthly (QM) for 36 months (from Day 1 to Day 1009). In case of bleeding events participants will receive IV CFCs or BPAs. Participants may receive Antithrombin concentrate (ATIIIC) as rescue medicine. .
Receives: Drug: Fitusiran; Drug: Clotting factor concentrates (CFC) or bypassing agents (BPA); Drug: Antithrombin concentrate (ATIIIC)

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Annualized bleeding rate (ABR) in the fitusiran primary efficacy period

    A bleeding episode is defined as any occurrence of hemorrhage that requires administration of CFCs or BPAs, e.g., hemarthrosis, muscle, or mucosal bleeding.

    Measured: Day 169 to Day 505 (since the first dose of fitusiran)

Secondary outcomes (9)
  1. Annualized bleeding rate (ABR) while on fitusiran prophylaxis in the fitusiran primary efficacy period and ABR while on prophylaxis standard of care (SOC) in the SOC period

    A bleeding episode is defined as any occurrence of hemorrhage that requires administration of CFCs or BPAs, e.g., hemarthrosis, muscle, or mucosal bleeding.

    Measured: Day 169 to Day 505 (primary efficacy period) and Day -168 to Day -1 (SOC period)

  2. Annualized bleeding rate (ABR) while on fitusiran prophylaxis in the fitusiran primary efficacy period and ABR while on on-demand standard of care (SOC) in the SOC period

    A bleeding episode is defined as any occurrence of hemorrhage that requires administration of CFCs or BPAs, e.g., hemarthrosis, muscle, or mucosal bleeding.

    Measured: Day 169 to Day 505 (primary efficacy period) and Day -168 to Day -1 (SOC period)

  3. Annualized spontaneous bleeding rate in the fitusiran primary efficacy period and in the SOC period

    A bleeding episode is defined as any occurrence of hemorrhage that requires administration of CFCs or BPAs, e.g., hemarthrosis, muscle, or mucosal bleeding.

    A spontaneous bleeding episode is a bleeding event that occurs for no apparent or known reason, particularly into the joints, muscles, and soft tissues.

    Measured: Day 169 to Day 505 (primary efficacy period) and Day -168 to Day -1 (SOC period)

  4. Annualized joint bleeding rate in the fitusiran primary efficacy period and in the SOC period

    A bleeding episode is defined as any occurrence of hemorrhage that requires administration of CFCs or BPAs, e.g., hemarthrosis, muscle, or mucosal bleeding.

    A joint bleeding episode is characterized by an unusual sensation in the joint ("aura") in combination with 1) increasing swelling or warmth over the skin over the joint, 2) increasing pain, or 3) progressive loss of range of motion or difficulty in using the limb as compared with baseline.

    Measured: Day 169 to Day 505 (primary efficacy period) and Day -168 to Day -1 (SOC period)

  5. Change in Haem-A-QOL physical health score and total score during SOC and during fitusiran prophylaxis

    The Haem-A-QoL will be provided to participants ≥17 years of age and includes 46 items contributing to 10 QoL domains (physical health, feelings, view of yourself, sports and leisure, work and school, dealing with hemophilia, treatment, future, family planning, partnership, and sexuality). Scoring for each item is based on a 5-point Likert scale (never, rarely, sometimes, often, and all the time), and higher scores represent greater impairment.

    Measured: Day 1 (D1) to Day 505, and from D1 to Day 1009, and during SOC from Day-168 to D-1

  6. Annualized bleeding rate (ABR) in the fitusiran 18-month efficacy period

    A bleeding episode is defined as any occurrence of hemorrhage that requires administration of CFCs or BPAs, e.g., hemarthrosis, muscle, or mucosal bleeding.

    Measured: Day 1 to Day 505

  7. Annualized bleeding rate (ABR) in the fitusiran 36-month treatment period

    A bleeding episode is defined as any occurrence of hemorrhage that requires administration of CFCs or BPAs, e.g., hemarthrosis, muscle, or mucosal bleeding.

    Measured: Day 1 to Day 1009

  8. Annualized weight-adjusted consumption of CFC/BPA

    All CFC or BPA doses (including doses per kg body weight) administered during the study treatment will be recorded

    Measured: Day -168 until Day 1009

  9. Number of participants with adverse events

    All AEs (serious or nonserious) will be collected from the signing of the informed consent form (ICF) until last AT follow up visit.

    Measured: Date of signed ICF (Day -228 to Day -169) until last visit (approximately 50 months after date of signed ICF)

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted22 Dec 2022
  2. Study start1 Feb 2023
  3. Primary completion25 Mar 2027 (estimated)
  4. Study completion25 Jan 2029 (estimated)

Resources

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 3
Primary purpose
Treatment
Allocation
Not applicable
Intervention model
Crossover
Model description
One way cross-over
Masking
None (open label)
Enrolment
91 participants (actual)
IDs, dates and publications
ClinicalTrials.gov ID
NCT05662319
Sponsor's protocol ID
EFC17574
Other IDs
U1111-1275-9584, 2022-500221-33
Acronym
ATLAS-NEO
Status last verified
Feb 2026
First submitted
14 Dec 2022
Last updated
4 Feb 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

Questions about this trial

What is this clinical trial studying?

A Phase 3 study testing Fitusiran, Clotting factor concentrates (CFC) or bypassing agents (BPA) and Antithrombin concentrate (ATIIIC) in people with Hemophilia, run by Sanofi at 50 sites in 17 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 3 inclusion and 15 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: under way, not looking for participants, as of the sponsor's last update on 4 Feb 2026. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 50 sites in United States, India, Turkey (Türkiye), Canada, China and 12 more countries. 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 3 studies compare the treatment with the current standard treatment or a placebo in a large group, to confirm how well it works and watch for side effects.

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?

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Annualized bleeding rate (ABR) in the fitusiran primary efficacy period (time frame: Day 169 to Day 505 (since the first dose of fitusiran)). 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 4 Feb 2026.

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