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Study on the Safety and Tolerability of BIIB115 for Children with Spinal Muscular Atrophy Previously Treated with Gene Therapy

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What is this trial about?

A plain-language summary of the goals, design and what participants do

This clinical trial is focused on studying a condition known as Spinal Muscular Atrophy (SMA), a genetic disorder that affects the control of muscle movement. The study will evaluate a treatment called BIIB115, which is a solution for injection. The purpose of the study is to assess the safety and tolerability of this treatment when given to participants. The study will involve two groups: healthy adult male volunteers and children with SMA who have previously been treated with a medication called onasemnogene abeparvovec, also known as Zolgensma™.

The study will be conducted in two parts. In the first part, healthy adult male participants will receive a single dose of BIIB115 through an injection into the space around the spinal cord, a method known as intrathecal injection. In the second part, children with SMA will receive multiple doses of BIIB115 using the same method. The study aims to monitor any side effects and how the body processes the medication over time. Participants will be observed for any adverse events, which are any unwanted effects that occur during the study.

The trial will also measure the concentration of BIIB115 in the participants' blood and spinal fluid to understand how the drug is absorbed and eliminated by the body. This information will help determine the appropriate dosage and frequency of administration for future treatments. The study is expected to continue for several years to gather comprehensive data on the safety and effectiveness of BIIB115 in treating Spinal Muscular Atrophy.

The research process

The trial runs in 5 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Initial visit and screening

    Upon joining the study, an initial visit is conducted to confirm eligibility. This involves a review of medical history and a physical examination to ensure good health for participation.

    For pediatric participants, a genetic diagnosis of spinal muscular atrophy (SMA) is confirmed, and previous treatment with onasemnogene abeparvovec is verified.

  2. Step 2

    First dose administration

    The first dose of BIIB115 is administered through an injection into the spinal canal, known as intrathecal injection. This is done to deliver the medication directly to the central nervous system.

    For healthy adult male participants, this is a single dose. For pediatric participants with SMA, multiple doses are administered over time.

  3. Step 3

    Monitoring and follow-up

    After the dose administration, participants are monitored for any side effects or adverse reactions. This includes regular check-ups and assessments to ensure safety and tolerability.

    For healthy adult male participants, monitoring continues up to 393 days. For pediatric participants, monitoring extends up to 720 days.

  4. Step 4

    Additional dose administration for pediatric participants

    Pediatric participants receive additional doses of BIIB115 as part of the multiple ascending dose study. The frequency and number of doses are determined by the study protocol.

    Each dose is followed by monitoring to assess the concentration of the medication in the body and to evaluate its effects.

  5. Step 5

    Final assessments and study completion

    At the end of the study period, final assessments are conducted to evaluate the overall safety and effectiveness of the treatment.

    Participants may undergo various tests and evaluations to measure the concentration of BIIB115 in the body and to determine the treatment's impact on their condition.

Who can join the trial?

10 criteria

  • Part A - Must be a healthy male aged between 18 to 55 years.
  • Part A - Must have a body mass index (BMI) between 18 to 30. BMI is a measure of body fat based on height and weight.
  • Part A - Must be in good health as determined by the study doctor, based on medical history and health checks.
  • Part B - Must be aged between 0.5 to 12 years at the time of giving consent to participate.
  • Part B - Must weigh at least 7 kilograms at the time of giving consent.
  • Part B - Must have a genetic diagnosis of Spinal Muscular Atrophy (SMA). This means having specific changes in the genes related to SMA.
  • Part B - Must have at least one copy of the SMN2 gene. This gene is related to the production of a protein important for muscle function.
  • Part B - Must have received a treatment called onasemnogene abeparvovec, which is given through a vein, according to the approved guidelines.
  • Part B - Must have received the onasemnogene abeparvovec treatment at least 180 days before the first dose of the study medication.
  • Part B - Must have the potential for improvement due to less than optimal health status related to SMA, as determined by the study doctor.

Who cannot join the trial?

9 criteria

  • Participants who have not been previously treated with onasemnogene abeparvovec cannot join. This is a specific treatment for spinal muscular atrophy.
  • Participants who cannot receive an intrathecal (IT) bolus injection are excluded. This is a method of delivering medication directly into the space around the spinal cord.
  • Participants with any other medical condition that might interfere with the study results are not allowed to participate.
  • Participants who are unable to comply with the study procedures and requirements will be excluded.
  • Participants who have any allergies or reactions to the study medication or its components cannot take part.
  • Participants who are currently involved in another clinical trial are not eligible.
  • Participants who have a history of drug or alcohol abuse may be excluded.
  • Participants who are pregnant or breastfeeding cannot participate.
  • Participants who have any significant medical conditions that could affect their safety or the study outcomes are not allowed to join.
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Investigated drugs

  • BIIB115

    is a medication being studied to see how safe and tolerable it is for people. In this trial, it is given to healthy adult men and children with a condition called Spinal Muscular Atrophy (SMA). The medication is administered through an injection into the spinal fluid. The study aims to understand how the body handles the medication and to ensure it is safe for use in these groups of people.

  • Onasemnogene Abeparvovec (Zolgensma™)

    is a treatment that some children with Spinal Muscular Atrophy (SMA) have already received before participating in this study. It is a gene therapy designed to help improve muscle movement and strength in children with SMA. This therapy works by delivering a new, working copy of a gene that is missing or not working properly in these children, helping to improve their condition. In this trial, it is not being tested directly but is part of the participants' previous treatment history.

What is already known about the treatment

BIIB115 – BIIB115 is administered through an intrathecal bolus injection, which means it is injected directly into the spinal canal. This medication is currently being studied in clinical trials to assess its safety and tolerability, particularly in individuals with spinal muscular atrophy (SMA), a genetic disorder affecting muscle strength and movement. The main therapeutic indication for BIIB115 is to help manage symptoms of SMA, especially in patients who have previously received treatment with onasemnogene abeparvovec. At the molecular level, BIIB115 is designed to work by targeting specific genetic components involved in SMA, potentially helping to improve muscle function. It falls under the pharmacological classification of gene therapy, which aims to address the underlying genetic causes of diseases.

Investigated diseases

Spinal Muscular Atrophy – Spinal Muscular Atrophy (SMA) is a genetic disorder characterized by the progressive degeneration of motor neurons in the spinal cord. This leads to muscle weakness and atrophy, primarily affecting the proximal muscles, which are closer to the center of the body. The disease progresses with a loss of motor function, impacting activities such as crawling, walking, sitting, and head control. SMA is classified into different types based on the age of onset and severity of symptoms. Over time, individuals with SMA may experience difficulties with breathing and swallowing due to muscle weakness. The progression rate and severity can vary significantly among individuals with the condition.
Trial detailsLast updated 2 Oct 2026
Age18+ yearsPhasePhase ITrial ID2023-505643-39-00Protocol code277HV101Estimated enrolment62 patientsSponsorBiogen Idec Research Limited

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