A Study to Learn About Salanersen's (BIIB115) Effects on Movement and Its Safety When Given Before Symptoms Appear in Babies With Genetically Diagnosed Spinal Muscular Atrophy (SMA)

An Open-Label Study to Assess the Efficacy and Safety of Multiple Doses of Salanersen (BIIB115) Delivered Intrathecally to Treatment-Naive, Presymptomatic Infants With Genetically Diagnosed Spinal Muscular Atrophy - 277SM302 (STELLAR-1)

Status

Recruiting

Phases

Phase 3

Study type

Interventional

Source

JPRN

Registry ID

JPRN-jRCT2031260161

Enrollment

Registered

2026-05-28

Start date

2026-06-30

Completion date

Unknown

Last updated

2026-06-29

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Muscular Atrophy, Spinal

Interventions

In Part1, 2 doses of 80 mg salanersen will be administered by IT injection approximately 12 months apart. After completion of Part1, subjects will proceed to Part2 where 3 doses of 80 mg salanersen wi

Eligibility

Sex/Gender

All

Inclusion criteria

Inclusion criteria: == 2 millivolt (mV) at Screening and Day 1 predose. 4) Body weight >=3rd percentile for age based on World Health Organization (WHO) Child Growth Standards at the time of informed consent.

Exclusion criteria

Exclusion criteria: 1) Any clinical signs or symptoms at Screening or Day 1 predose that are, in the opinion of the Investigator, strongly suggestive of SMA. 2) Areflexia on neurologic examination at biceps, knee, or ankle at Screening or Day 1 Predose. 3) Hypoxemia (oxygen saturation 1000 meters (m), oxygen saturation of <92% awake or asleep without any supplemental oxygen or respiratory support). 4) Diagnosis of neonatal respiratory distress syndrome necessitating surfactant replacement therapy or invasive ventilatory support. 5) Any reason, anatomical or otherwise (including hematology/coagulation laboratory results), that presents increased risk of complication from the LP procedures or safety assessments. 6) Any prior treatment with an approved SMA disease-modifying therapy (e.g., nusinersen, onasemnogene abeparvovec-xioi [OA], and/or risdiplam), a myostatin inhibitor therapy, or an investigational drug given for the treatment of SMA.

Design outcomes

Primary

Measure	Time frame
1) Part 1: Percentage of Participants with 2 Survival Motor Neuron 2 (SMN2) Copies Sitting Without Support (for at Least 10 Seconds) [Time Frame: At Month 12] 2) Part 1: Percentage of Participants with 3 SMN2 Copies Walking Alone (for at Least 5 Steps) [Time Frame: At Month 18] 3) Part 2: Percentage of Participants Attaining and Maintaining World Health Organization (WHO) Motor Milestones [Time Frame: Up to Day 1825] The WHO motor milestones will include six key developmental milestones: sitting without support, standing with assistance, hands-and-knees crawling, walking with assistance, standing alone, and walking alone.	—

Measure

Time frame

1) Part 1: Percentage of Participants with 2 Survival Motor Neuron 2 (SMN2) Copies Sitting Without Support (for at Least 10 Seconds) [Time Frame: At Month 12] 2) Part 1: Percentage of Participants with 3 SMN2 Copies Walking Alone (for at Least 5 Steps) [Time Frame: At Month 18] 3) Part 2: Percentage of Participants Attaining and Maintaining World Health Organization (WHO) Motor Milestones [Time Frame: Up to Day 1825] The WHO motor milestones will include six key developmental milestones: sitting without support, standing with assistance, hands-and-knees crawling, walking with assistance, standing alone, and walking alone.

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Secondary

Measure	Time frame
1) Part 1: Percentage of Participants Attaining World Health Organization (WHO) Motor Milestones [Time Frame: Up to Day 730] 2) Parts 1 and 2: Percentage of Participants Attaining Hammersmith Infant Neurological Examination Section 2 (HINE-2) Motor Milestones [Time Frame: Up to Day 1825] 3) Parts 1 and 2: Change From Baseline in Children's Hospital of Philadelphia Infant Test of Neuromuscular Disorders (CHOP INTEND) Motor Function Scale [Time Frame: Up to Day 1825] 4) Parts 1 and 2: Change From Baseline in Compound Muscle Action Potential (CMAP) Amplitudes [Time Frame: Up to Day 1825] 5) Part 1: Percentage of Participants who Remain Free of Clinically Manifested Spinal Muscular Atrophy (SMA) [Time Frame: Up to Day 730] 6) Part 2: Hammersmith Functional Motor Scale Expanded (HFMSE) Total Score [Time Frame: Up to Day 1825] 7) Part 2: Change From Baseline in Hammersmith Functional Motor Scale Expanded (HFMSE) [Time Frame: Up to Day 1825] 8) Part 2: Revised Upper Limb Module (RULM) Total Score [Time Frame: Up to Day 1825] 9) Part 2: Change From Baseline in Revised Upper Limb Module (RULM) [Time Frame: Up to Day 1825] 10) Part 2: Percentage of Participants who Develop Spinal Muscular Atrophy (SMA) Subtypes (Type 1, 2,3a and 3b) As Assessed by the Investigator [Time Frame: Up to Day 1825] 11) Parts 1 and 2: Time to Death (Overall Survival) [Time Frame: Up to Day 1825] 12) Parts 1 and 2: Time to Death or Permanent Ventilation [Time Frame: Up to Day 1825] 13) Parts 1 and 2: Number of Participants with Adverse Events (AEs) and Serious Adverse Events (SAEs) [Time Frame: Up to Day 1825] 14) Parts 1 and 2: Concentration of Salanersen in Cerebrospinal Fluid (CSF) [Time Frame: Up to Day 1460] 15) Parts 1 and 2: Concentration of Salanersen in Serum [Time Frame: Up to Day 1825] 16) Parts 1 and 2: Change From Baseline in Plasma Levels of Neurofilament Light Chain (NfL) [Time Frame: Up to Day 1825]	—

Measure

Time frame

1) Part 1: Percentage of Participants Attaining World Health Organization (WHO) Motor Milestones [Time Frame: Up to Day 730] 2) Parts 1 and 2: Percentage of Participants Attaining Hammersmith Infant Neurological Examination Section 2 (HINE-2) Motor Milestones [Time Frame: Up to Day 1825] 3) Parts 1 and 2: Change From Baseline in Children's Hospital of Philadelphia Infant Test of Neuromuscular Disorders (CHOP INTEND) Motor Function Scale [Time Frame: Up to Day 1825] 4) Parts 1 and 2: Change From Baseline in Compound Muscle Action Potential (CMAP) Amplitudes [Time Frame: Up to Day 1825] 5) Part 1: Percentage of Participants who Remain Free of Clinically Manifested Spinal Muscular Atrophy (SMA) [Time Frame: Up to Day 730] 6) Part 2: Hammersmith Functional Motor Scale Expanded (HFMSE) Total Score [Time Frame: Up to Day 1825] 7) Part 2: Change From Baseline in Hammersmith Functional Motor Scale Expanded (HFMSE) [Time Frame: Up to Day 1825] 8) Part 2: Revised Upper Limb Module (RULM) Total Score [Time Frame: Up to Day 1825] 9) Part 2: Change From Baseline in Revised Upper Limb Module (RULM) [Time Frame: Up to Day 1825] 10) Part 2: Percentage of Participants who Develop Spinal Muscular Atrophy (SMA) Subtypes (Type 1, 2,3a and 3b) As Assessed by the Investigator [Time Frame: Up to Day 1825] 11) Parts 1 and 2: Time to Death (Overall Survival) [Time Frame: Up to Day 1825] 12) Parts 1 and 2: Time to Death or Permanent Ventilation [Time Frame: Up to Day 1825] 13) Parts 1 and 2: Number of Participants with Adverse Events (AEs) and Serious Adverse Events (SAEs) [Time Frame: Up to Day 1825] 14) Parts 1 and 2: Concentration of Salanersen in Cerebrospinal Fluid (CSF) [Time Frame: Up to Day 1460] 15) Parts 1 and 2: Concentration of Salanersen in Serum [Time Frame: Up to Day 1825] 16) Parts 1 and 2: Change From Baseline in Plasma Levels of Neurofilament Light Chain (NfL) [Time Frame: Up to Day 1825]

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Countries

Japan, USA

Contacts

Public ContactBiogen Japan Medical Information

Biogen Japan Ltd.

japan-medinfo@biogen.com+81-120-560-086

Outcome results

None listed

Source: JPRN (via WHO ICTRP) · Data processed: Jul 3, 2026