Fitusiran Prophylaxis in Male Pediatric Subjects Aged 1 to Less Than 12 Years With Hemophilia A or B (ATLAS-PEDS)

ATLAS-PEDS: An Open-label, Multinational Study of Fitusiran Prophylaxis in Male Pediatric Subjects Aged 1 to Less Than 12 Years With Hemophilia A or B

Primary Objective:

- To confirm appropriate dose levels of fitusiran when administered to male pediatric participants (ages 1 to <12 years of age) with severe hemophilia A or B

Secondary Objectives:

• To characterize the safety and tolerability
• To determine fitusiran plasma concentrations at selected time points

Study Overview

• Status: Active, not recruiting
• Conditions: Hemophilia
• Intervention / Treatment: Drug: Fitusiran

Detailed Description

The estimated total time on study is up to 256 weeks for participants who roll over into the extension study and up to 280 weeks for participants who do not roll over into the extension study (due to the requirement for up to an additional 6 months of follow-up for monitoring of AT levels).

• Study Type: Interventional
• Enrollment (Actual): 32
• Phase: Phase 3

Contacts and Locations

Study Locations

• Canada
  • Ontario
    • Hamilton, Ontario, Canada, L8N 3Z5
      • Investigational Site Number : 1240001
    • Ottawa, Ontario, Canada, K1H 8L1
      • Investigational Site Number : 1240002
• India
  • Bangalore, India, 560034
    • Investigational Site Number : 3560006
  • Mumbai, India, 400 022
    • Investigational Site Number : 3560002
  • Pune-411011, India, 411 011
    • Investigational Site Number : 3560001
  • Vellore, India, 632004
    • Investigational Site Number : 3560004
• Italy
  • Firenze, Italy, 50134
    • Investigational Site Number : 3800002
  • Milano, Italy, 20122
    • Investigational Site Number : 3800001
• Spain
  • Madrid, Comunidad De
    • Madrid, Madrid, Comunidad De, Spain, 28046
      • Investigational Site Number : 7240002
• Turkey
  • Adana, Turkey, 01130
    • Investigational Site Number : 7920001
  • Istanbul, Turkey, 34093
    • Investigational Site Number : 7920002
  • Izmir, Turkey, TR-35100
    • Investigational Site Number : 7920003
• United States
  • California
    • Los Angeles, California, United States, 90027
      • Children's Hospital Los Angeles Site Number : 8400002
  • New Jersey
    • Hackensack, New Jersey, United States, 07601
      • Hackensack University Medical Center- Site Number : 8400008
  • Ohio
    • Cleveland, Ohio, United States, 44106
      • University Hospitals of Cleveland- Site Number : 8400007
  • Pennsylvania
    • Hershey, Pennsylvania, United States, 17033
      • Penn State Milton S. Hershey Medical Center- Site Number : 8400006

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 1 year to 11 years (Child)
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Male, aged 1 to <12 years at the time of enrollment.
• Severe hemophilia A or B (Factor VIII (FVIII) <1% or Factor IX (FIX) ≤2%)

• Participants must have inhibitory antibodies to FVIII or FIX and must meet one of the following Nijmegen-modified Bethesda assay results criteria:

  • 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 1 inhibitor titer ≥0.6 BU/mL and a history of anamnestic response or severe allergic reaction (anaphylaxis or nephrotic syndrome)
• Adequate peripheral venous access, as determined by the Investigator, to allow the blood draws required by the study protocol
• Weight requirements at the time of enrollment: 8 to <45 kg
• Willing and able to comply with the study requirements and to provide signed written informed consent obtained from parent(s)/legal guardian (hereinafter the "parent") and written or oral assent obtained from participant, per local and national requirements

Exclusion Criteria:

Participants are excluded from the study if any of the following criteria apply:

• Known co-existing bleeding disorders other than hemophilia A or B
• Antithrombin (AT) activity <60% at Screening
• Co-existing thrombophilic disorder
• Clinically significant liver disease
• Active Hepatitis C virus infection
• Acute or chronic Hepatitis B virus infection
• Acute Hepatitis A or hepatitis E infection
• HIV positive with a CD4 count of <400 cells/μL
• History of arterial or venous thromboembolism, unrelated to an indwelling venous access
• Inadequate renal function
• History of multiple drug allergies or history of allergic reaction to an oligonucleotide or N-Acetylgalactosamine (GalNAc)
• Subjects with central or peripheral indwelling catheters, with history of venous access complications leading to hospitalization and/or systemic anticoagulation therapy.
• History of intolerance to subcutaneous (SC) injection(s)
• Use of emicizumab (Hemlibra®) within 6 months prior to screening
• Any other conditions or comorbidities that would make the patient unsuitable for enrollment or could interfere with participation in or completion of the study, per Investigator judgment

The above information is not intended to contain all considerations relevant to a patient's potential participation in a clinical trial.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Fitusiran; Participants will receive a selected dose of fitusiran at regular intervals, as per study protocol	Drug: Fitusiran; Pharmaceutical form:Solution for injection-Route of administration:Subcutaneous; Other Names: SAR439774

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Plasma antithrombin (AT) activity levels	Characterize the AT activity at the optimal therapeutic dose	Day 1 to the AT analysis time point at the optimal therapeutic dose (approximately 256 weeks)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Number of participants reported with adverse events	Number of participants reported with treatment-emergent adverse events (TEAEs)	Up to 280 weeks (up to 256 weeks of treatment + up to 24 weeks of AT follow up)
Fitusiran plasma concentrations	Plasma samples will be collected for measurement of plasma concentrations of fitusiran at specific time points post dose on Day 1 and pre dose on Day 85	Day 1 and Day 85

Collaborators and Investigators

• Sponsor: Genzyme, a Sanofi Company
• Investigators: Study Director: Clinical Sciences & Operations, Sanofi

Study record dates

Study Major Dates

• Study Start (Actual): January 28, 2020
• Primary Completion (Estimated): August 15, 2026
• Study Completion (Estimated): December 15, 2026

Study Registration Dates

• First Submitted: June 3, 2019
• First Submitted That Met QC Criteria: June 3, 2019
• First Posted (Actual): June 4, 2019

Study Record Updates

• Last Update Posted (Actual): August 8, 2025
• Last Update Submitted That Met QC Criteria: August 7, 2025
• Last Verified: August 1, 2025

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Genetic Diseases, Inborn; Hematologic Diseases; Blood Coagulation Disorders; Hemorrhagic Disorders; Blood Coagulation Disorders, Inherited; Coagulation Protein Disorders; Hemophilia A
• Other Study ID Numbers: EFC15467; 2019-000679-18 (EudraCT Number); U1111-1223-4368 (Registry Identifier: ICTRP); 2024-512501-76 (Registry Identifier: CTIS)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: 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

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: Yes
• Studies a U.S. FDA-regulated device product: No