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Apitegromab for infants under 2 with spinal muscular atrophy

A Phase 2, Double-Blind Study to Evaluate the Pharmacokinetics, Pharmacodynamics, Efficacy, and Safety of Apitegromab in Subjects <2 Years Old With Spinal Muscular Atrophy (SMA)

Phase 2 Interventional Scholar Rock, Inc. · NCT07047144

This trial will test whether adding apitegromab to approved SMA therapy helps infants under 2 with 5q SMA reach better motor milestones.

Quick facts

PhasePhase 2
Study typeInterventional
Enrollment52 (estimated)
AgesN/A to 2 Years
SexAll
SponsorScholar Rock, Inc. Industry-sponsored
Drugs / interventionsapitegromab
Locations25 sites (Phoenix, Arizona and 24 other locations)
Trial IDNCT07047144 on ClinicalTrials.gov

What this trial studies

This is a double-blind, Phase 2, multiple-dose trial testing apitegromab in infants under 2 years with 5q autosomal recessive spinal muscular atrophy who have delayed motor milestones or a CHOP-INTEND score under 55. Participants must be receiving or have received approved SMN-targeted therapy (for example, onasemnogene abeparvovec, nusinersen, or risdiplam) and will be monitored for pharmacokinetics, pharmacodynamics, safety, tolerability, and motor outcomes. The study compares repeated doses of apitegromab against control while continuing background SMA therapy to see if additional benefit on motor function can be achieved. Outcomes will include PK/PD measures and changes in standardized motor function scores over the treatment period.

Who should consider this trial

Good fit: Ideal candidates are infants under 2 years with confirmed 5q SMA, documented SMN2 copy number, delayed motor milestones or CHOP-INTEND <55, who are on or have received approved SMN-targeted therapy and meet the growth and gestational criteria.

Not a fit: Infants with stable good motor function, unstable nutritional status or predominant feeding by gastrostomy, or major orthopedic limitations are unlikely to benefit from this trial.

Why it matters

Potential benefit: If successful, apitegromab could help infants on existing SMN therapies gain additional motor function and reach developmental milestones sooner.

How similar studies have performed: Early-phase studies of myostatin-targeting approaches including apitegromab have shown promising signals for added motor benefit in older children or adults on SMN therapy, but data in infants under 2 are limited.

Eligibility criteria

Show full inclusion / exclusion criteria 
Inclusion Criteria:

1. 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:

1. 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 procedure, including spine or hip surgery, which is considered to have the potential to substantially limit the ability of the subject to be evaluated on any motor function outcome measures, within 6 months before Screening or anticipated during the study
3. Any other physical limitations (eg, the subject requires cast for contractures) that would prevent the subject from undergoing motor function outcome measures throughout the study.

Where this trial is running

Phoenix, Arizona and 24 other locations

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
View on ClinicalTrials.gov → Find more trials like this →
Conditions Spinal Muscular AtrophySMASpinal Muscular Atrophy Type 2Spinal Muscular Atrophy Type 3Neuromuscular ManifestationsAnti-myostatin
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.