A Study to Assess the Safety, Tolerability, Efficacy, Pharmacokinetics, and Immunogenicity of Intravenous Administration of ARGX-119 in Pediatric Participants Aged 5 to Less Than 18 Years With Spinal Muscular Atrophy
Sparkle
A Phase 2 Double-Blinded, Randomized, Placebo-Controlled Study to Assess the Safety, Tolerability, Efficacy, Pharmacokinetics, and Immunogenicity of Intravenous Administration of ARGX-119 in Pediatric Participants Aged 5 to Less Than 18 Years With Spinal Muscular Atrophy
2 other identifiers
interventional
60
1 country
17
Brief Summary
This study aims to find the correct dose of ARGX-119 for children with SMA. The study will also look at how safe the study drug is, how well it works, how it moves through the body, and how the immune system responds to it. The study consists of a double-blinded treatment period (DBTP) where participants will either receive ARGX-119 IV or placebo IV, in addition to disease-modifying therapy (DMT) for 24 weeks. Participants who complete the DBTP will enter the open-label active-treatment extension period (ATEP) during which all participants will receive ARGX-119 IV up to 100 weeks (approximately 2 years).
Trial Health
Trial Health Score
Automated assessment based on enrollment pace, timeline, and geographic reach
participants targeted
Target at P50-P75 for phase_2
Started Dec 2025
Typical duration for phase_2
17 active sites
Health score is calculated from publicly available data and should be used for screening purposes only.
Trial Relationships
Click on a node to explore related trials.
Study Timeline
Key milestones and dates
First Submitted
Initial submission to the registry
December 15, 2025
CompletedFirst Posted
Study publicly available on registry
December 17, 2025
CompletedStudy Start
First participant enrolled
December 19, 2025
CompletedPrimary Completion
Last participant's last visit for primary outcome
May 28, 2029
ExpectedStudy Completion
Last participant's last visit for all outcomes
May 28, 2029
April 22, 2026
April 1, 2026
3.4 years
December 15, 2025
April 17, 2026
Conditions
Keywords
Outcome Measures
Primary Outcomes (3)
Incidence of AEs
Adverse Events
Up to 124 weeks
Incidence of SAEs
Serious Adverse Events
Up to 124 weeks
Change in RHS total score from baseline to week 24 of the double blinded treatment period (DBTP)
The RHS (Revised Hammersmith Scale) is a validated 36-item scale developed to evaluate the spectrum of gross motor function. Maximum total score; 69 (optimal motor function)
Up to 24 weeks
Secondary Outcomes (3)
Change from baseline over time for the 6MWT - distance and fatigue index
Up to 124 weeks
ARGX-119 serum concentrations over time
Up to 124 weeks
Incidence of antidrug antibodies (ADA) against ARGX-119
Up to 124 weeks
Study Arms (3)
DBTP - ARGX-119 IV
EXPERIMENTALParticipants receive ARGX-119 IV during the DBTP
DBTP - Placebo IV
PLACEBO COMPARATORParticipants receive placebo IV during the DBTP
ATEP - ARGX-119 IV
PLACEBO COMPARATORParticipants receive ARGX-119 IV during the ATEP. Participants from ARGX-119 IV arm in the DBTP will receive placebo once to maintain the DBTP blinding
Interventions
Eligibility Criteria
You may qualify if:
- Is aged ≥5 to \<18 years when completing the informed consent process, defined as providing informed assent according to local regulations and having a parent or guardian sign the ICF, and can comply with protocol
- requirements.
- Has documented historical genetic diagnosis of 5q-SMA.
- Currently receiving a stable SMA treatment regimen (nusinersen or risdiplam) and/or have a history of onasemnogene abeparvovec treatment
- Must be able to walk at least 50 meters without walking aids in the 6MWT at screening
You may not qualify if:
- Known medical condition that would interfere with an accurate assessment of SMA, confound the results of the study, or put the participant at undue risk, as assessed by the investigator
- Recent major surgery, except spinal fusion, within 3 months of screening or intends to have major surgery during the study
- Current or previous administration of antimyostatin therapies in the past 6 months
- Severe scoliosis (defined as curvature \>40°) and/or contractures at screening. o History of spinal fusion within 6 months before screening or planned during the study
- Respiratory insufficiency, defined by the medical necessity for invasive or noninvasive ventilation for daytime treatment while awake. Ventilation used overnight or during daytime naps is acceptable.
Contact the study team to confirm eligibility.
Sponsors & Collaborators
- argenxlead
Study Sites (17)
Arkansas Children's Hospital
Little Rock, Arkansas, 72202, United States
Rady Childrens Hospital
San Diego, California, 92123, United States
Stanford University Medical Center
Stanford, California, 94305, United States
Connecticut Children's Medical Center
Hartford, Connecticut, 06106, United States
Rare Disease Research FL LLC
Kissimmee, Florida, 34746, United States
Ann & Robert H. Lurie Children's Hospital of Chicago
Chicago, Illinois, 60611, United States
University of Iowa Stead Family Children's Hospital
Iowa City, Iowa, 52242, United States
The Johns Hopkins Hospital
Baltimore, Maryland, 21205, United States
Boston Children's Hospital
Boston, Massachusetts, 02115, United States
The Curators of the University of Missouri on behalf of University of Missouri Health Care
Columbia, Missouri, 65212, United States
Columbia University Herbert Irving Comprehensive Cancer Center
New York, New York, 10032, United States
Rare Disease Research NC, LLC
Hillsborough, North Carolina, 27278, United States
Children's Hospital Philadelphia - Neurology
Philadelphia, Pennsylvania, 19104, United States
St. Jude Children's Research Hospital
Memphis, Tennessee, 38105, United States
Neurology Rare Disease Center
Flower Mound, Texas, 75028, United States
Texas Children's Hospital
Houston, Texas, 77030, United States
Childrens Hospital of The Kings Daughters
Norfolk, Virginia, 23507, United States
MeSH Terms
Conditions
Condition Hierarchy (Ancestors)
Central Study Contacts
Study Design
- Study Type
- interventional
- Phase
- phase 2
- Allocation
- RANDOMIZED
- Masking
- DOUBLE
- Who Masked
- PARTICIPANT, INVESTIGATOR
- Purpose
- TREATMENT
- Intervention Model
- PARALLEL
- Sponsor Type
- INDUSTRY
- Responsible Party
- SPONSOR
Study Record Dates
First Submitted
December 15, 2025
First Posted
December 17, 2025
Study Start
December 19, 2025
Primary Completion (Estimated)
May 28, 2029
Study Completion (Estimated)
May 28, 2029
Last Updated
April 22, 2026
Record last verified: 2026-04
Data Sharing
- IPD Sharing
- Will not share