Spinal Muscular AtrophyPhase 3ONYXNCT05626855
Long-Term Safety & Efficacy of Apitegromab in Patients With SMA Who Completed Previous Trials of Apitegromab
A Phase 3 study testing Apitegromab in people with Spinal Muscular Atrophy and Spinal Muscular Atrophy Type 3, run by Scholar Rock, Inc. at 49 sites in 9 countries.
Trial summary
The ONYX study is an Open-Label, Multicenter, Extension study that will evaluate the long-term safety and efficacy of Apitegromab in Patients with Type 2 and Type 3 SMA who have completed TOPAZ or SAPPHIRE. Read more about this study
- Who is it for?
- Ages 2 years and older
- Conditions the study is for
- Spinal Muscular Atrophy, Spinal Muscular Atrophy Type 3, Spinal Muscular Atrophy Type 2
- What is being tested?
- Apitegromab
- Type of treatment
- Injection or infusion
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 238 participants
- Where
- 49 sitesin 9 countries
- Study dates
- 17 Apr 2023to 2 May 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 2 years and older
- All sexes
- No healthy volunteers
- Child, Adult, Older adult
Who may be able to join
- Patients have completed the Phase 2 TOPAZ (Study SRK-015-002) trial or the Phase 3 SAPPHIRE (Study SRK-015-003) trial. (For TOPAZ, completed is defined as completion of Visit EC14 in Extension Period C or participating in TOPAZ at the time the trial is ended. For SAPPHIRE, completed is defined as completion of Visit 14 or participating in SAPPHIRE at the time the trial is ended)
- Estimated life expectancy >2 years from the Baseline Visit (Day 1)
- Able to receive study drug infusions and provide blood samples through the use of a peripheral IV or a long-term IV access device that the patient has placed for reasons independent from the trial
- Able to adhere to the requirements of the protocol, including travel to the trial site and completing all trial procedures and trial visits
- Females of childbearing potential must have a negative pregnancy test at the Baseline Visit and agree to use at least 1 highly effective method of contraception throughout the trial and for 20 weeks after the last dose of apitegromab
Who cannot join
- Patient permanently discontinued study treatment during the feeder trial (i.e., TOPAZ or SAPPHIRE)
- Nutritional status that was not stable over the past 6 months and is not anticipated to be stable throughout the trial or medical necessity for a gastric/nasogastric feeding tube, where the majority of feeds are given by this route, as assessed by the Investigator
- Patient is currently enrolled in any investigational drug trial other than TOPAZ or SAPPHIRE
- Prior history of severe hypersensitivity reaction or intolerance to SMN-targeted therapies
- Prior history of severe hypersensitivity reaction or intolerance to apitegromab
- Use of chronic daytime noninvasive ventilatory support for >16 hours daily in the 2 weeks before dosing, or anticipated to regularly receive such daytime ventilator support chronically throughout the trial
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- Any acute or comorbid condition interfering with the well-being of the patient at the patient's last visit in TOPAZ or SAPPHIRE, (including active systemic infection, the need for acute treatment, or inpatient observation due to any reason). After resolution of the condition, the patient can be enrolled in the trial if they meet all the other eligibility criteria.
- Pregnant or breastfeeding
- Any other condition or clinically significant laboratory result or ECG value that, in the opinion of the Investigator, may compromise safety or compliance, would preclude the patient from successful completion of the trial, or interfere with the interpretation of the results
Trial locations and contacts
49 sites in 9 countries.
49 sites in 9 countries
United States25 sites
Children's Hospital Colorado
Aurora, Colorado, 80045
Johns Hopkins Hospital
Baltimore, Maryland, 21287
Boston Children's Hospital
Boston, Massachusetts, 02115
Lurie Children's Hospital of Chicago
Chicago, Illinois, 60611
Nationwide Children's Hospital
Columbus, Ohio, 43215
University of Texas Southwestern - Pediatric Neurology
Dallas, Texas, 75207
University of Kansas Medical Center
Fairway, Kansas, 66205
Helen DeVos Children's Hospital
Grand Rapids, Michigan, 49503
University of Iowa
Iowa City, Iowa, 52242
UCSD Altman Clinical and Translational Research
La Jolla, California, 92037
Children's Hospital Los Angeles
Los Angeles, California, 90027
University of Wisconsin Hospital
Madison, Wisconsin, 53792
St. Jude Children's Research Hospital
Memphis, Tennessee, 38105
Columbia University Medical Center
New York, New York, 10032
Children's Specialty Group PLLC (Children's Hospital of The King's Daughters)
Newport News, Virginia, 23606
Nemours Biomedical Research
Orlando, Florida, 32827
Stanford Neuroscience Health Center
Palo Alto, California, 94304
The Children's Hospital of Philadelphia
Philadelphia, Pennsylvania, 19104
Phoenix Childrens Hospital
Phoenix, Arizona, 85016
Oregon Health & Science University
Portland, Oregon, 97239
Gillette Children's Specialty Healthcare
Saint Paul, Minnesota, 55101
University of Utah
Salt Lake City, Utah, 84112
Seattle Children's Hospital
Seattle, Washington, 98115
Washington University Medical Campus
St Louis, Missouri, 63110
Wake Forest University School of Medicine
Winston-Salem, North Carolina, 27157
Italy5 sites
Istituto Giannina Gaslini, Centro Traslazionale di Miologia e Patologie Neurodegenerative
Genova, 16147
UOC NEUROLOGIA E MALATTIE NEUROMUSCOLARI A.O.U Policlinico G. Martino
Messina, 98125
Carlo Besta Neurological Research Institute
Milan, 20133
NeuroMuscular Omnicentre
Milan, 20162
Fondazione Policlinico Universitario A. Gemelli
Roma, 106
Germany4 sites
Universitätskinderklinik Bonn, Abteilung für Neuropädiatrie und SPZ
Bonn, 53127
Universitatsklinikum Essen
Essen, 45147
Universitatsklinikum Freiburg
Freiburg im Breisgau, 79106
Klinikum der Universitat Munchen, Dr. von Haunersches Kinderspital, Abteilung fur Kinderneurologie und Entwicklungsneurologie
Munchen, Bayern, 80337
Belgium3 sites
UZ Gent
Ghent, 9000
UZ Leuven
Leuven, 3000
CHR Citadelle
Liège, 4000
France3 sites
CHRU de Lille - Hpital Jeanne de Flandre
Lille, 59037
Hopital Trousseau - I-Motion
Paris, 75012
CHU Toulouse Hopital des Enfants
Toulouse, 31059
Poland3 sites
Uniwersyteckie Centrum Kliniczne
Gdansk, 80-211
Uniwersytecki Szpital Kliniczny w Poznaniu, Oddział Kliniczny Neurologii Dzieci i Młodzieży
Poznan, 60-355
Instytut Pomnik - Centrum Zdrowia Dziecka
Warsaw, 04-730
United Kingdom3 sites
Leeds Children's Hospital Clinical Research
Leeds, LS1 3EX
Great Ormond Street Hospital for Children
London, WC1N 1EH
University of Oxford
Oxford, OX3 0ER
Spain2 sites
Hospital Sant Joan de Deau
Barcelona, 08950
Hospital Universitari i Politecnic La Fe
Valencia, 46026
About this study
Official title: An Open-Label, Multicenter, Extension Trial to Evaluate the Long-Term Safety and Efficacy of Apitegromab in Patients With Type 2 and Type 3 Spinal Muscular Atrophy Who Completed Previous Investigational Trials of Apitegromab
The ONYX study is an Open-Label, Multicenter, Extension study that will evaluate the long-term safety and efficacy of Apitegromab in Patients with Type 2 and Type 3 SMA who have completed TOPAZ or SAPPHIRE.
- Conditions
- Spinal Muscular Atrophy, Spinal Muscular Atrophy Type 3, Spinal Muscular Atrophy Type 2, SMA, Neuromuscular Diseases, Muscular Atrophy
- Being tested
- Apitegromab
- Medical subject headings
- Muscular Atrophy, Spinal, Spinal Muscular Atrophies of Childhood, Neuromuscular Diseases, Muscular Atrophy, Atrophy, Neuromuscular Manifestations
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
ApitegromabDrug
Apitegromab (SRK-015) is an investigational, fully human immunoglobulin G4 monoclonal antibody that specifically binds to human proforms (i.e., inactive precursor forms) of myostatin, pro- and latent- myostatin, with high affinity, inhibiting activation of myostatin, a negative regulator of muscle growth and strength.
| Study group | Role | What they receive |
|---|---|---|
| Treatment Period | Experimental | Patients who are ≥2 years of age with Type 2 and Type 3 SMA will receive apitegromab 20 mg/kg every 4 weeks by intravenous (IV) infusion during the 104-week Treatment Period Receives: Drug: Apitegromab |
What is being measured
The primary outcome is the main question the study is designed to answer.
Evaluate the long-term safety and tolerability of apitegromab in patients with Type 2 and Type 3 SMA
Incidence of TEAEs and SAEs by severity
Measured: Up to 6 years
Secondary outcomes (7)
Evaluate the long-term efficacy of apitegromab by assessing changes in motor function outcome measures at prespecified time points
Hammersmith Functional Motor Scale Expanded (HFMSE) total score at prespecified time points (excludes ambulatory patients)
Measured: Up to 6 years
Evaluate the long-term efficacy of apitegromab by assessing changes in motor function outcome measures at prespecified time points
Revised Upper Limb Module (RULM) total score at prespecified time points (excludes ambulatory patients)
Measured: Up to 6 years
Evaluate the long-term efficacy of apitegromab by assessing changes in motor function outcome measures at prespecified time points
Number of World Health Organization (WHO) motor development milestones attained at prespecified time points (excludes ambulatory patients)
Measured: Up to 6 years
Evaluate the long-term efficacy of apitegromab by assessing changes in motor function outcome measures at prespecified time points
Revised Hammersmith Scale (RHS) total score
Measured: Up to 6 years
Evaluate the long-term efficacy of apitegromab by assessing changes in motor function outcome measures at prespecified time points
Results for 6-Minute Walk Test
Measured: Up to 6 years
Evaluate the long-term efficacy of apitegromab by assessing changes in motor function outcome measures at prespecified time points
30-Second Sit-to-Stand
Measured: Up to 6 years
Further evaluate the immunogenicity of apitegromab
Presence or absence of antidrug antibody (ADA) against apitegromab in serum from blood samples
Measured: Up to 6 years
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted25 Nov 2022
- Study start17 Apr 2023
- Primary completion1 Nov 2026 (estimated)
- Study completion2 May 2029 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Spinal Muscular AtrophyStudies of the same condition, open and under way.
- 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 3
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Single group
- Model description
- Open Label Extension Study
- Masking
- None (open label)
- Enrolment
- 238 participants (actual)
Sponsor and investigators
- Lead sponsor
- Scholar Rock, Inc.
- Sponsor type
- Industry (pharma, biotech, devices)
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05626855
- Sponsor's protocol ID
- SRK-015-004
- Acronym
- ONYX
- Status last verified
- Aug 2026
- First submitted
- 7 Nov 2022
- Last updated
- 1 Sep 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 1 Sep 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- An Open-Label, Multicenter, Extension Trial to Evaluate the Long-Term Safety and Efficacy of Apitegromab in Patients With Type 2 and Type 3 Spinal Muscular Atrophy Who Completed Previous Investigational Trials of Apitegromab
- ClinicalTrials.gov ID
- NCT05626855
- Acronym / sponsor ID
- ONYX / SRK-015-004
- Conditions
- Spinal Muscular Atrophy, Spinal Muscular Atrophy Type 3, Spinal Muscular Atrophy Type 2, SMA, Neuromuscular Diseases, Muscular Atrophy
- Phase
- Phase 3
- Study type
- Interventional
- Recruitment status
- Active, not recruiting
- Enrolment
- 238 participants (actual)
- Lead sponsor
- Scholar Rock, Inc.Industry (pharma, biotech, devices)
- Study start
- 17 Apr 2023 (actual)
- Primary completion
- 1 Nov 2026 (estimated)
- Study completion
- 2 May 2029 (estimated)
- First posted
- 25 Nov 2022 (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.
The ONYX study is an Open-Label, Multicenter, Extension study that will evaluate the long-term safety and efficacy of Apitegromab in Patients with Type 2 and Type 3 SMA who have completed TOPAZ or SAPPHIRE.
Study design
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 1
- Model description
- Open Label Extension Study
| Arm | Type | Receives |
|---|---|---|
| Treatment Period | Experimental | Drug: ApitegromabPatients who are ≥2 years of age with Type 2 and Type 3 SMA will receive apitegromab 20 mg/kg every 4 weeks by intravenous (IV) infusion during the 104-week Treatment Period |
Who may qualify
- Ages
- 2 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Child, Adult, Older adult
Key inclusion criteria (5 listed)
- Patients have completed the Phase 2 TOPAZ (Study SRK-015-002) trial or the Phase 3 SAPPHIRE (Study SRK-015-003) trial. (For TOPAZ, completed is defined as completion of Visit EC14 in Extension Period C or participating in TOPAZ at the time the trial is ended. For SAPPHIRE, completed is defined as completion of Visit 14 or participating in SAPPHIRE at the time the trial is ended)
- Estimated life expectancy >2 years from the Baseline Visit (Day 1)
- Able to receive study drug infusions and provide blood samples through the use of a peripheral IV or a long-term IV access device that the patient has placed for reasons independent from the trial
- Able to adhere to the requirements of the protocol, including travel to the trial site and completing all trial procedures and trial visits
- Females of childbearing potential must have a negative pregnancy test at the Baseline Visit and agree to use at least 1 highly effective method of contraception throughout the trial and for 20 weeks after the last dose of apitegromab
Key exclusion criteria (9 listed)
- Patient permanently discontinued study treatment during the feeder trial (i.e., TOPAZ or SAPPHIRE)
- Nutritional status that was not stable over the past 6 months and is not anticipated to be stable throughout the trial or medical necessity for a gastric/nasogastric feeding tube, where the majority of feeds are given by this route, as assessed by the Investigator
- Patient is currently enrolled in any investigational drug trial other than TOPAZ or SAPPHIRE
- Prior history of severe hypersensitivity reaction or intolerance to SMN-targeted therapies
- Prior history of severe hypersensitivity reaction or intolerance to apitegromab
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 |
|---|---|---|
| ApitegromabApitegromab (SRK-015) is an investigational, fully human immunoglobulin G4 monoclonal antibody that specifically binds to human proforms (i.e., inactive precursor forms) of myostatin, pro- and latent- myostatin, with high affinity, inhibiting activation of myostatin, a negative regulator of muscle growth and strength. | Drug | Treatment Period |
Primary outcome
Evaluate the long-term safety and tolerability of apitegromab in patients with Type 2 and Type 3 SMA
Time frame: Up to 6 years
Incidence of TEAEs and SAEs by severity
7 secondary outcomes
Evaluate the long-term efficacy of apitegromab by assessing changes in motor function outcome measures at prespecified time points
Time frame: Up to 6 years
Evaluate the long-term efficacy of apitegromab by assessing changes in motor function outcome measures at prespecified time points
Time frame: Up to 6 years
Evaluate the long-term efficacy of apitegromab by assessing changes in motor function outcome measures at prespecified time points
Time frame: Up to 6 years
Evaluate the long-term efficacy of apitegromab by assessing changes in motor function outcome measures at prespecified time points
Time frame: Up to 6 years
Evaluate the long-term efficacy of apitegromab by assessing changes in motor function outcome measures at prespecified time points
Time frame: Up to 6 years
Evaluate the long-term efficacy of apitegromab by assessing changes in motor function outcome measures at prespecified time points
Time frame: Up to 6 years
Further evaluate the immunogenicity of apitegromab
Time frame: Up to 6 years
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 1 Sep 2026.
- Individual participant dataSharing planned: No
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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. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
49 sites in 9 countries: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 3 study testing Apitegromab in people with Spinal Muscular Atrophy and Spinal Muscular Atrophy Type 3, run by Scholar Rock, Inc. at 49 sites in 9 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 5 inclusion and 9 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 1 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 49 sites in United States, Italy, Germany, Belgium, France and 4 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?
Evaluate the long-term safety and tolerability of apitegromab in patients with Type 2 and Type 3 SMA (time frame: Up to 6 years). 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 1 Sep 2026.