Purpose

The primary objective of this study is to evaluate motor function following treatment with HD nusinersen in participants with spinal muscular atrophy (SMA) previously treated with risdiplam. The secondary objective of this study is to evaluate the safety and tolerability of HD nusinersen in participants with SMA previously treated with risdiplam.

Condition

Eligibility

Eligible Ages
Between 15 Years and 50 Years
Eligible Genders
All
Accepts Healthy Volunteers
No

Inclusion Criteria

  • Genetic documentation of 5q SMA homozygous survival motor neuron-1 (SMN1) gene deletion or mutation or compound heterozygous mutation. - Diagnosis of later-onset SMA with symptom onset at age >6 months. - Aged ≥15 to ≤50 years at the time of informed consent - Body weight >20 kg. - Received oral risdiplam per the approved label or per the managed access program as follows 1. Nusinersen-naive participants must have had prior treatment with risdiplam for ≥6 months before enrollment. 2. Nusinersen-experienced participants must have stopped nusinersen for ≥16 months and must have been on risdiplam for ≥12 months before enrollment. - Able to perform the age-appropriate functional assessments in the study. - RULM entry item A score ≥3. - RULM total score ≥5 and ≤30 at Screening. - Nonambulatory, defined as not able to walk 15 feet (4.57 meters) independently without support. - Willing to stop risdiplam treatment. - Willing and able to start treatment with HD nusinersen.

Exclusion Criteria

  • Any major illness within 1 month before the screening examination or within 1 week prior to Screening and up to first dose administration. - Presence of an untreated or inadequately treated active infection requiring systemic antiviral or antimicrobial therapy at any time during the Screening Period. - Presence of an implanted shunt for the drainage of CSF or of an implanted central nervous system catheter. - Permanent tracheostomy or permanent ventilation at Screening. - The medical necessity, as defined by the Investigator, for noninvasive ventilation such as bilevel positive airway pressure or continuous positive airway pressure outside of regular sleep hours for any reason other than proactive SMA management, at Screening. - History of bacterial meningitis, viral encephalitis, or hydrocephalus. - Ongoing medical condition that according to the Investigator would interfere with the conduct and assessments of the study. An example is a medical disability (e.g., wasting or cachexia, severe anemia, and respiratory parameters) that would interfere with the assessment of safety or would compromise the ability of the participant to undergo study procedures. - Participants who are pregnant or currently breastfeeding and those intending to become pregnant during the study. - Treatment with an investigational drug, biological agent, or device within 30 days or 5 half-lives of the agent, whichever is longer, prior to Screening or anytime during the study; any prior or current treatment with gene therapy for the treatment of SMA. NOTE: Other protocol defined Inclusion/Exclusion criteria may apply.

Study Design

Phase
Phase 3
Study Type
Interventional
Allocation
N/A
Intervention Model
Single Group Assignment
Primary Purpose
Treatment
Masking
None (Open Label)

Arm Groups

ArmDescriptionAssigned Intervention
Experimental
Higher Dose Nusinersen
All participants in the core study period, previously treated with risdiplam (nusinersen-naive participants and nusinersen-experienced participants), will receive HD nusinersen, administered as 2 loading doses of 50 milligrams (mg) each, approximately 2 weeks apart, followed by maintenance doses of 28 mg approximately every 4 months. Following the core study period, participants may be given the opportunity to receive maintenance doses of 28 mg nusinersen administered approximately every 4 months up to 2 years during the optional long-term extension (LTE) period.
  • Drug: Nusinersen
    Administered as specified in the treatment arm
    Other names:
    • BIIB058
    • Spinraza

Recruiting Locations

Georgetown University
Washington, District of Columbia 20007
Contact:
202-444-8525

More Details

Status
Recruiting
Sponsor
Biogen

Study Contact

US Biogen Clinical Trial Center
866-633-4636
clinicaltrials@biogen.com

Notice

Study information shown on this site is derived from ClinicalTrials.gov (a public registry operated by the National Institutes of Health). The listing of studies provided is not certain to be all studies for which you might be eligible. Furthermore, study eligibility requirements can be difficult to understand and may change over time, so it is wise to speak with your medical care provider and individual research study teams when making decisions related to participation.