NCT07047144 · Scholar Rock, Inc.
A Study to Evaluate How Apitegromab Works in Subjects Who Are Less Than 2 Years Old and Have Spinal Muscular Atrophy
(OPAL)
What this study is about
This where neither patients nor doctors know which treatment is given, Phase 2, multiple-dose study will be conducted to evaluate the PK/PD, effectiveness, safety, and tolerability of apitegromab in subjects \<2 years old with 5q autosomal recessive SMA who have delayed motor milestones for their age attributed to SMA at the discretion of the Investigator or a Children's Hospital of Philadelphia Infant Test of Neuromuscular Disorders (CHOP-INTEND) score \<55.
View original scientific description
This double-blind, Phase 2, multiple-dose study will be conducted to evaluate the PK/PD, efficacy, safety, and tolerability of apitegromab in subjects \<2 years old with 5q autosomal recessive SMA who have delayed motor milestones for their age attributed to SMA at the discretion of the Investigator or a Children's Hospital of Philadelphia Infant Test of Neuromuscular Disorders (CHOP-INTEND) score \<55.
Interventions
DRUG
Apitegromab
Apitegromab is a fully human anti-proMyostatin monoclonal antibody (mAb) of the immunoglobulin G4 (IgG4)/lambda isotype that specifically binds to human pro/latent myostatin with high affinity inhibiting myostatin activation. SRK-015 will be administered every 4 weeks by intravenous (IV) infusion.
DRUG
Nusinersen
Nusinersen is a current standard-of-care SMN therapy that targets the SMN2 gene. It will be administered intrathecally per the prescribing information.
DRUG
Risdiplam
Risdiplam is a current standard-of-care SMN therapy that targets the SMN2 gene. It will be administered orally per the prescribing information.
Primary outcome measures
Evaluate the PK of apitegromab in subjects <2 years old with SMA
Time frame: 52 Weeks
Apitegromab concentrations in serum
Evaluate the PD of apitegromab in subjects <2 years old with SMA
Time frame: 52 Weeks
Total latent myostatin concentrations in serum
Evaluate the motor function outcomes (ie, efficacy) due to apitegromab treatment
Time frame: 48 Weeks
Change from baseline in the raw score of the Bayley Scale of Infant and Toddler Development, Fourth Edition - Gross Motor Subscale (BSID-4 GMS) at 48 weeks. BSID-4 GMS is a standardized assessment commonly used to evaluate development across 5 domains in infants and young children. It consists of 58 items, scored from 0 to 2 for each item, with higher scores indicating better gross motor development.
Who can participate
This study lists these criteria on ClinicalTrials.gov. A study coordinator reviews eligibility during screening — this page does not determine whether you qualify.
Inclusion criteria
- Is \<2 years old at the time of the informed consent 2. Had a gestational age of ≥35 weeks and gestational body weight ≥2.0 kg at birth 3. Has confirmed diagnosis of 5q autosomal recessive SMA 4. Has confirmed presence of SMN2 gene copy(ies) 5. Must have been treated with an approved SMN1-targeted therapy (ie, onasemnogene abeparvovec-xioi) or are continuing to be treated with an approved SMN2-targeted therapy (ie, nusinersen or risdiplam) 6. Body weight for age is no less than 1st percentile based on the WHO Child Growth Standards at the Screening Visit 7. Has delayed motor milestones for age attributed to SMA at the discretion of the Investigator or a CHOP-INTEND score \<55
Exclusion criteria
- Nutritional status that is not anticipated to be stable throughout the study or medical necessity for a gastric feeding tube, where most feeds are administered by this route 2. Major orthopedic issues such as severe scoliosis or severe contractures or interventional
Where
- Phoenix, Arizona
- Orange, California
- Palo Alto, California
- Aurora, Colorado
- Atlanta, Georgia
- Iowa City, Iowa
- Grand Rapids, Michigan
- Winston-Salem, North Carolina
- Philadelphia, Pennsylvania
- Memphis, Tennessee
- Dallas, Texas
- Flower Mound, Texas
And 2 more locations — see the full list below.
Related conditions & keywords
Frequently asked questions
What is a clinical trial?
A clinical trial is a research study that tests new medical treatments, drugs, devices, or procedures to determine their safety and effectiveness. Trials are carefully designed and monitored to protect participants while advancing medical knowledge.
Is it safe to participate?
Clinical trials follow strict safety guidelines and ethical standards. Trials must be reviewed and approved, and participants are closely monitored by medical professionals throughout the study. You can withdraw at any time if you choose.
Will I be compensated?
Many clinical trials offer compensation for your time, travel expenses, and inconvenience. The specific compensation varies by study and will be discussed during the screening process. All study-related medical care is typically provided at no cost to participants.
Will I receive a placebo instead of treatment?
When effective treatment exists, participants typically receive either the standard treatment plus the study intervention, or the standard treatment plus placebo. You would not be denied effective care. Placebos are primarily used when no proven treatment is available, or in addition to standard care. Your trial consent form will clearly explain what treatments you may receive.
Can I leave a trial if I change my mind?
Absolutely. Participation in clinical trials is completely voluntary. You have the right to withdraw from the study at any time, for any reason, without penalty or loss of benefits to which you are otherwise entitled.
How long does a clinical trial last?
Trial duration varies widely depending on the study design and purpose. Some trials last just a few weeks, while others may continue for months or years. The study coordinator will provide specific timeline information during your screening call.
Data: ClinicalTrials.gov · synced May 1, 2026 · Source of record for eligibility and locations