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Study of ION373 Given by Spinal Injection for Patients with Alexander Disease

Verified siteInvestigationalNo placebo
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What is this trial about?

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

This study focuses on patients with Alexander Disease, a rare genetic condition that affects the nervous system. The research evaluates a new medication called ION373, which is given through an injection into the spinal fluid. The medication is designed to target a specific protein that is involved in the disease process.

The study tests how well ION373 works in improving or stabilizing movement abilities in people with Alexander Disease. Some participants will receive the actual medication, while others will receive a placebo. The medication or placebo will be given through injections into the space around the spinal cord, known as intrathecal administration.

During the study, participants will receive the treatment for 61 weeks. The researchers will monitor how well participants can walk and move, along with other symptoms related to Alexander Disease. They will also check the safety of the treatment and measure certain substances in the spinal fluid to understand how the medication works in the body.

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 treatment period

    You will receive either ION373 or a placebo through intrathecal injection (delivered directly into the spinal fluid)

    This phase will last for 61 weeks (approximately 14 months)

    Regular visits will be scheduled to monitor your progress and conduct assessments

  2. Step 2

    Medical assessments

    If you are 5 years or older, you will complete a 10-meter walking test to assess your movement ability

    If you are under 5 years old, your gross motor function will be evaluated using specific movement tests

    If you are 8 years or older, you will complete a 9-hole peg test to assess hand function

    Your doctor will assess your overall condition and any changes in symptoms throughout the study

  3. Step 3

    Additional evaluations

    Regular assessment of your most bothersome symptoms

    Completion of quality of life questionnaires

    Monitoring of body weight

    Collection of spinal fluid samples to measure GFAP levels (a protein associated with Alexander Disease)

  4. Step 4

    Safety monitoring

    Regular medical check-ups throughout the study period

    If you are of reproductive age, pregnancy tests will be conducted every 12 weeks

    Monitoring for any side effects or changes in your condition

  5. Step 5

    Study completion

    Final evaluations will be conducted at week 61

    Assessment of changes in your condition compared to the start of the study

    Review of all collected data and measurements

Who can join the trial?

9 criteria

  • Patient must provide written informed consent and be able to follow all study requirements
  • Age requirements: - For main study: between 2 and 65 years old - For open-label sub-study: less than 2 years old
  • Must have confirmed genetic mutation in the GFAP gene
  • Must have brain imaging results consistent with Alexander Disease
  • Physical ability requirements: - Ages 2-5 years: must be able to sit with minimal support for at least 10 seconds or walk (with or without assistance) completing a 10-meter walk test within 5 minutes - Ages 5 and above: must be able to walk (with or without assistance)
  • Must be on stable medications, nutrition plan, and therapy programs (physical, occupational, speech, respiratory) for at least 3 months before screening
  • For patients under 18: must have a trial partner (parent or caregiver) who is: - At least 18 years old - Available to accompany patient to visits - Knowledgeable about patient's condition
  • For females of reproductive age: - Must not be pregnant or breastfeeding - Must use effective contraception or be surgically sterile - Regular pregnancy testing will be required
  • For males who can father children: - Must use effective contraception or be surgically sterile - Must continue contraception for 40 weeks after last dose

Who cannot join the trial?

12 criteria

  • Patients who do not have a confirmed genetic diagnosis of Alexander Disease
  • Individuals who have participated in another clinical trial within the past 30 days
  • Patients with severe allergic reactions to similar medications
  • Those with significant liver or kidney problems that could affect drug metabolism
  • Pregnant women or those planning to become pregnant during the study period
  • Patients who are currently receiving other experimental treatments
  • Individuals who have undergone major surgery in the past 3 months
  • Patients with uncontrolled medical conditions that could interfere with the study
  • Those unable to comply with study procedures or follow-up visits
  • Patients taking medications that could interact with the study drug ION373
  • Individuals with severe psychiatric conditions that could impact their participation
  • Those who cannot provide informed consent or have legal guardians who cannot provide consent
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Investigated drugs

ION373 is an experimental medication that is administered through an intrathecal injection (directly into the spinal fluid). This medication is being studied for the treatment of Alexander disease, a rare genetic condition that affects the nervous system. The treatment is designed to target the underlying cause of Alexander disease with the goal of improving or stabilizing patients' ability to move and control their muscles.

What is already known about the treatment

ION373 - An investigational medication administered intrathecally (directly into the spinal fluid) that is being studied for the treatment of Alexander Disease, a rare genetic neurological disorder. This drug is currently undergoing Phase 1-3 clinical trials to evaluate its effectiveness in improving or stabilizing gross motor function in patients with Alexander Disease. ION373 belongs to a class of therapeutic agents designed to target the underlying genetic cause of the disease, though the exact molecular mechanism is still being investigated through clinical research. The medication represents a potential breakthrough in treating this rare condition, for which there are currently limited treatment options.

Investigated diseases

Alexander Disease - A rare genetic disorder that primarily affects the brain and spinal cord due to mutations in the GFAP gene. The disease causes the destruction of white matter in the brain, which affects transmission of nerve signals. It leads to the abnormal formation of protein deposits called Rosenthal fibers in specialized brain cells known as astrocytes. The condition typically causes progressive problems with movement, speech, and swallowing. Alexander Disease can develop at any age, with symptoms varying depending on when the disease first appears. The disease affects various functions of the nervous system, including coordination, mental development, and autonomic functions.
Trial detailsLast updated 2 Oct 2026
Age18+ yearsPhasePhase I/IITrial ID2024-510603-11-00Protocol codeION373-CS1Estimated enrolment57 patientsSponsorIonis Pharmaceuticals Inc.

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On this site, “treatment” means an investigational medicine being studied in a clinical trial. Its safety and efficacy for the use being studied have not yet been confirmed, some participants may receive a placebo or a comparator medicine, and taking part does not guarantee any health benefit. The decision to take part is made by the doctor at the research site. This site is for information only and does not replace medical advice.

This service is not affiliated with the European Commission, the EMA, or the official CTIS system. Most information comes from publicly available international clinical-trial registries, supplemented by data from academic sites, national regulators and commercial sponsors. On this site, “treatment” and “therapy” mean a medicine being tested in a clinical trial. Its safety and effectiveness in the use being studied are not yet confirmed, some participants may receive a placebo or a comparator, and taking part does not guarantee a health benefit. The doctor at the research site decides who can take part. This site provides information, not medical advice. Certain content and visual elements on this website have been generated or enhanced using artificial intelligence (AI).