A Study to Learn About Salanersen's (BIIB115) Effects on Movement and Its Safety in Participants Aged 15 to 60 Years With Spinal Muscular Atrophy (SMA) Who Are Either New to SMA Treatment or Were Previously Treated With Risdiplam

An Open-Label, Phase 3 Study to Evaluate the Efficacy and Safety of Salanersen (BIIB115) in Participants Aged 15-60 Years With Spinal Muscular Atrophy Who Are Either Treatment-Naïve or Have Previously Been Treated With Risdiplam

A Study to Learn About Salanersen's (BIIB115) Effects on Movement and Its Safety in Participants Aged 15 to 60 Years With Spinal Muscular Atrophy (SMA) Who Are Either New to SMA Treatment or Were Previously Treated With Risdiplam (NCT07444476) is a Phase 3 interventional studying Spinal Muscular Atrophy, sponsored by Biogen. RECRUITING as of the most recent ClinicalTrials.gov update. Talk to your doctor before contacting the trial site.

About This Trial

In this study, researchers will learn more about the effects and safety of BIIB115, also known as salanersen. Specifically, researchers will learn more about how salanersen works in individuals with SMA who are between the ages of 15 and 60 years old. In most people living with SMA, changes to or a lack of a gene called survival motor neuron 1 (SMN1) - often referred to as gene mutations or variants - affect how this gene works. As a result, their bodies produce less SMN protein. Without enough of this protein, motor neurons and muscles cannot work properly. There is a similar gene called SMN2 that produces SMN protein, but it usually does not produce enough SMN protein on its own to make up for the changes in the SMN1 gene. Salanersen is a drug designed to help the SMN2 gene to make more working SMN protein. In this study, there will be 2 groups of participants: a group who has never received treatment for SMA before joining this study, and a group who has been treated with risdiplam, an approved drug for SMA . Those participants must not have received any other SMA treatments before and will need to stop their risdiplam treatment for the duration of the study. The main goal of this study is to learn more about how salanersen affects the participants' motor function. Researchers will use different tests and questionnaires to learn if motor function is changing over the study duration. The main question researchers want to answer in this study is: • For the group who has never been treated for SMA, how much do scores on the HFMSE movement test change at 12 months compared to the beginning of the study? The Hammersmith Functional Motor Scale - Expanded (HFMSE) has 33 activities that are scored which include sitting, lying down, walking, jumping, and more. Researchers will also learn more about: * The effects on participants' motor function and how well their nerves and muscles function. * The effects on participants' overall sense of change and how they perform daily activities. * How many participants have adverse events or serious adverse events. Adverse events are health problems that may or may not be caused by the study drug. * How much salanersen gets into the fluid surrounding the brain and spinal cord. * How much salanersen gets into the blood. This study will be done as follows: * First, participants will be screened to check if they can join the study. The screening period may be up to 4 weeks. * This is an "open-label" study. This is a study in which the participants, study doctor, and site staff will know that participants are receiving salanersen. * All participants will receive salanersen through an intrathecal injection, or one that is given into the fluid surrounding the brain and spinal cord. * Participants will receive salanersen once every year for a total of 5 times throughout the study. * Including screening, participants will have 17 study visits and 9 telephone calls during this study, which will last up to 61 months in total.

What Stage of Research Is This?

Phase 3 trials confirm efficacy and safety in large patient groups (often 300–3,000+) and form the evidence base for an FDA approval submission. For Spinal Muscular Atrophy, Phase 3 studies typically randomize participants between the investigational treatment and either a placebo or current standard of care. A successful Phase 3 result is the threshold most treatments need to clear before regulatory approval.

This trial is currently recruiting participants. The sponsor has registered the study with ClinicalTrials.gov as actively enrolling, which means new applicants who meet the eligibility criteria can be considered for screening. Trial status can change between updates — confirm current recruiting status with the study contact before traveling for a screening visit.

Target enrollment of 90 participants puts this in the typical range for a Phase 2-style efficacy study or a moderate Phase 3 trial in a focused Spinal Muscular Atrophy subpopulation. At this scale, the study has enough statistical power to detect a clear treatment effect but is not the largest cohort in the field.

Who May Be Eligible (Plain English)

Key Who May Qualify: - Participants aged 15 to 60 years, inclusive, at the time of willing to sign a consent form - Participants with genetic documentation of 5q Spinal Muscular Atrophy (SMA) (homozygous gene deletion or mutation or compound heterozygous mutation). - Participants with clinical signs and symptoms consistent with SMA. - Survival motor neuron 2 (SMN2) copy number ≥ 1. - Participants with baseline Hammersmith Functional Motor Scale - Expanded (HFMSE) total score of ≥ 10 to ≤ 54. - Participants who are able to sit without using support for at least 10 seconds. - Participants with no prior treatment with myostatin inhibitors and a willingness to remain off concurrent myostatin inhibitor therapy for the duration of the study. - Ambulatory and nonambulatory participants: - Ambulatory participants must be able to walk at least 10 meters independently without assistance and are willing and able to complete the 6 Minute Walk Test (6MWT) at Screening. - For participants in the treatment-naïve cohort: - No prior treatment with an approved SMA Disease Modifying Therapy (DMT) or an investigational drug given for the treatment of SMA. - For participants in the risdiplam-treated cohort: - Currently receiving risdiplam treatment and have been on once-daily 5 milligrams (mg) risdiplam treatment for at least 6 months prior to Screening. - Willing to stop risdiplam therapy for the duration of the study. The last dose of risdiplam must be taken the day before the first dose of salanersen. - No prior treatment with nusinersen, onasemnogene abeparvovec-xioi/onasemnogene abeparvovec-brve (OA), other approved DMTs for SMA or investigational drugs given for the treatment of SMA apart from risdiplam. Key Who Should NOT Join This Trial: - Respiratory insufficiency at Screening, defined by the medical necessity for invasive or noninvasive ventilation for \> 6 hours during a 24-hour period (except for nocturnal bilevel positive airway pressure). ...See full criteria on ClinicalTrials.gov Always talk to your doctor about whether this trial is right for you.

These are translations of the protocol\'s inclusion and exclusion criteria, simplified for patients and caregivers. The original clinical text appears below. Eligibility is ultimately confirmed by the trial site\'s screening process — this summary is a starting point for a conversation with your doctor, not a final determination.

Original Eligibility Criteria

View original clinical language

Key Inclusion Criteria: * Participants aged 15 to 60 years, inclusive, at the time of informed consent * Participants with genetic documentation of 5q Spinal Muscular Atrophy (SMA) (homozygous gene deletion or mutation or compound heterozygous mutation). * Participants with clinical signs and symptoms consistent with SMA. * Survival motor neuron 2 (SMN2) copy number ≥ 1. * Participants with baseline Hammersmith Functional Motor Scale - Expanded (HFMSE) total score of ≥ 10 to ≤ 54. * Participants who are able to sit without using support for at least 10 seconds. * Participants with no prior treatment with myostatin inhibitors and a willingness to remain off concurrent myostatin inhibitor therapy for the duration of the study. * Ambulatory and nonambulatory participants: * Ambulatory participants must be able to walk at least 10 meters independently without assistance and are willing and able to complete the 6 Minute Walk Test (6MWT) at Screening. * For participants in the treatment-naïve cohort: * No prior treatment with an approved SMA Disease Modifying Therapy (DMT) or an investigational drug given for the treatment of SMA. * For participants in the risdiplam-treated cohort: * Currently receiving risdiplam treatment and have been on once-daily 5 milligrams (mg) risdiplam treatment for at least 6 months prior to Screening. * Willing to stop risdiplam therapy for the duration of the study. The last dose of risdiplam must be taken the day before the first dose of salanersen. * No prior treatment with nusinersen, onasemnogene abeparvovec-xioi/onasemnogene abeparvovec-brve (OA), other approved DMTs for SMA or investigational drugs given for the treatment of SMA apart from risdiplam. Key Exclusion Criteria: * Respiratory insufficiency at Screening, defined by the medical necessity for invasive or noninvasive ventilation for \> 6 hours during a 24-hour period (except for nocturnal bilevel positive airway pressure). * Medical necessity for a gastric feeding tube, where the majority of nutrition is provided by this route, as assessed by the site Investigator at Screening. * History of brain or spinal cord disease or other contraindications (e.g., severe scoliosis) that would interfere with the lumbar puncture (LP) procedures, Cerebrospinal fluid (CSF) circulation, efficacy assessments, or safety assessments (including a history of hydrocephalus or implanted shunt for CSF drainage), as assessed by the Investigator. * Hospitalization for surgery, a pulmonary event, or nutritional support within 2 months prior to Screening or plans to undergo elective procedures or surgeries at any time after signing the Informed Consent Form (ICF) through the end of the study. Note: If prior scoliosis surgery has been performed, it must be done at least 1 year prior to Screening. * Presence of an active medical issue (e.g., infection, recent fracture) that would make the participant unsuitable for inclusion, as assessed by the Investigator. * Current enrollment or a plan to enroll in any interventional clinical study in which an investigational treatment or approved therapy for investigational use is administered within 90 days or 5 half-lives of the treatment (if known), whichever is longer, prior to Screening. This includes neuromodulation therapy such as spinal cord stimulation. Note: Other protocol-defined inclusion/exclusion criteria will apply.

Treatments Being Tested

DRUG

Salanersen

Administered Intrathecally

Locations (1)

Trial sites listed on ClinicalTrials.gov for this study. Site activation status can vary — confirm with the specific site before traveling for a screening visit.

Childrens Hospital of the Kings Daughter Norfolk

Norfolk, Virginia, United States

How to Talk to Your Doctor About This Trial

Bring the printable summary of this trial — including the NCT ID (NCT07444476), the sponsor (Biogen), and the key eligibility criteria — to your next appointment. Your doctor can review the inclusion and exclusion criteria against your medical history, lab values, and current treatments to assess whether you are likely to qualify. They can also help you weigh whether trial participation makes sense alongside your existing care plan.

Useful questions to walk through together: What does the trial protocol require beyond standard care? How long is the active treatment phase, and how long is follow-up? Are there study visits at sites I can reach? Who pays for the trial-specific procedures, and who pays for standard-of-care portions? See our 25 questions to ask about clinical trials guide for a more complete checklist.

Authoritative Sources

The official record for this trial lives on ClinicalTrials.gov — the federal registry maintained by the National Library of Medicine at NIH. For background on how this trial fits into the FDA approval pathway, see the FDA drug approval process. For oncology-specific guidance for patients considering trials, the National Cancer Institute publishes patient-oriented overviews. International trial registries are aggregated by the WHO ICTRP.

Frequently Asked Questions

What is the NCT07444476 clinical trial studying?

Who can participate in NCT07444476?

Eligibility for this trial depends on the specific inclusion and exclusion criteria set by the sponsor. The plain-English summary above translates the most important criteria into accessible language; the official clinical text is preserved in the collapsible section underneath. Whether you fit any specific trial is a medical decision your doctor needs to confirm — bring the trial information to your treating physician for a full review against your medical history.

How do I contact the trial site for NCT07444476?

Contact information registered with ClinicalTrials.gov is shown in the sidebar of this page. Before reaching out, confirm with your treating physician that this trial is appropriate for your situation. The trial site will then walk you through the screening process to determine final eligibility.

Is participating in a clinical trial safe?

Clinical trials in the United States are regulated by the FDA and overseen by Institutional Review Boards (IRBs) that review the protocol for safety. Risk varies by trial — Phase 1 studies test new treatments in humans for the first time, while Phase 3 trials use treatments that have already passed earlier safety screening. The informed consent document for any specific trial details the known risks and what to expect. Discuss those risks with your physician before deciding whether to participate.

Where can I verify the data on this page?

Every detail on this page comes directly from the ClinicalTrials.gov API. Click "View on ClinicalTrials.gov" in the sidebar to see the official, unmodified record. The federal record is always authoritative; this page is a structured presentation with a plain-English eligibility translation. For background on how clinical trials are regulated, see the FDA drug approval process documentation.

How This Page Is Built

Every field on this page is pulled directly from the ClinicalTrials.gov API v2 — no estimates, no proxies. The plain-English eligibility translation is generated from the original protocol text and reviewed for fidelity to the underlying clinical criteria. The original clinical text remains visible in the collapsible section above so users and clinicians can verify the translation. Read the full methodology for the data pipeline and known limitations.

Source: ClinicalTrials.gov API v2 record for NCT07444476. Maintained by the National Library of Medicine at NIH. Public domain. Cite as: "TrialFinderData. NCT07444476. Data: ClinicalTrials.gov."

Medical disclaimer: This page is informational, not medical advice. Talk to your doctor about whether a clinical trial is right for you.

Last updated 2026-05-08 · Data from ClinicalTrials.gov.