Clinical trial Recruiting at 12 sites Phase1; Phase2 Interventional Ages 2 to 65 Men only

Evaluating ION440 for treating MECP2 Duplication Syndrome

Official title: A Phase 1-2, Double-Blind, Sham-Controlled Multiple Ascending Dose Study to Evaluate Safety, Tolerability, Pharmacokinetics, and Pharmacodynamics of Intrathecally-Administered ION440 in Patients With MECP2 Duplication Syndrome

Run by Ionis Pharmaceuticals, Inc. · NCT06430385 · Data updated 2026-11-12

This study is testing a new treatment called ION440 to see if it can help children and adults with MECP2 Duplication Syndrome feel better and improve their condition.

Quick facts

PhasePhase1; Phase2
Study typeInterventional
Ages2 Years to 65 Years
SexMen only
Enrollment48 (estimated)
SponsorIonis Pharmaceuticals, Inc.
Industry-sponsored
Locations12 sites (San Diego, California and 11 other locations)
StatusRecruiting
StartedOctober 21, 2024
Main results expectedSeptember 2027
Study endsApril 2030
Registry record updatedOctober 8, 2026
Trial IDNCT06430385 on ClinicalTrials.gov

Is this trial a fit for you?

Likely a good fit

Ideal candidates are males aged 2 to 65 years with a documented diagnosis of MECP2 Duplication Syndrome and genetic confirmation.

Probably not a fit

Patients without a confirmed diagnosis of MECP2 Duplication Syndrome or those who do not meet the age criteria may not benefit from this study.

A plain-English reading of the study's rules. Only the study team can confirm whether you qualify.

What this trial studies

This study evaluates the safety, tolerability, pharmacokinetics, and pharmacodynamics of ION440 administered intrathecally in participants with MECP2 Duplication Syndrome. It is a phase 1-2 randomized, double-blind, sham-controlled trial that consists of two parts: a multiple-ascending dose study followed by a long-term extension for those who complete the first part. Participants will be divided into age-based cohorts, with the first cohort including individuals aged 8 years and older, and the second cohort including those aged 2 to 7 years. The study aims to assess the effects of ION440 over a period of up to approximately 156 weeks.

Why it matters

Potential benefit: If successful, this treatment could provide a new therapeutic option for patients with MECP2 Duplication Syndrome, potentially improving their quality of life.

How similar studies have gone: While this approach is novel for MECP2 Duplication Syndrome, similar studies targeting genetic conditions have shown promise in the past.

Who can join: the full rules

Show full inclusion / exclusion criteria
Key Inclusion criteria for Part 1:

1. Males aged ≥ 2 to ≤ 65 years, depending on specific cohort and group, at the time of informed consent.

   1. Group A: ≥ 8 to ≤ 65 years old
   2. Group B: 2 to 7 years old, inclusive
2. Participant has at least one parent or caregiver ≥ 18 years old capable of providing informed consent and able to comply with all study requirements and activities.
3. Participant has a documented diagnosis of MDS with genetic confirmation of MECP2 duplication.
4. Is currently receiving stable doses of concomitant medications for at least 1 month prior to screening.
5. Able to complete all study procedures, measurements and visits to support primary and secondary endpoints, in the opinion of the Investigator.

Key Exclusion criteria for Part 1:

1. Documented diagnosis of severe MECP2 duplications including terminal duplication and/or translocation or MECP2 triplication OR clinical features associated with severe variant structure including (a) onset of seizures prior to age 5 (for those aged 5 and above at signing of ICF), (b) oxygen dependence, (c) microcephaly, IF MECP2 genetic structure information is unavailable.
2. Clinically significant vital sign or ECG abnormality at Screening
3. Known brain or spinal disease that would interfere with the LP procedure, or CSF circulation or presence of other factors would affect the safety of the LP procedure.
4. Has any concomitant disease or condition or circumstance, or any finding at Screening that, in the opinion of the Investigator, makes the participant unsuitable for enrollment or that could interfere with the conduct of the study or that would pose an unacceptable risk to the participant in this study.
5. Treatment with an investigational drug, biological agent, or device within 30 days of Screening, or 5 half-lives of investigational agent, whichever is longer.
6. Previous treatment with an oligonucleotide (including siRNA) within 4 months of Screening if single dose received, or within 12 months of Screening if multiple doses received (this exclusion does not apply to vaccines - both mRNA and viral vector vaccines are allowed including COVID-19). For centrally administered ASOs, a minimum of 12 months washout is required irrespective of the number of doses received.
7. Currently enrolled in a clinical trial of an investigational agent or device or has used any investigational agent or device within 5 half-lives of investigational agent, whichever is longer.
8. Has a history of gene therapy or cell transplantation or any other experimental brain surgery.
9. Active infection requiring systemic antiviral or antimicrobial therapy that will not be completed prior to Baseline (Day 1).
10. Has experienced Status Epilepticus in the past 6 months.

Key Inclusion criteria for Part 2:

1. Participants in ION440-CS1, Part 1/MAD who received at least one dose of Study Drug /Sham in Part 1/MAD, missed no more than 1 study visit, and attended the Follow Up visit (Visit 6).
2. All inclusion criteria in Part 1/MAD apply (participants will not be required to undergo new Screening bloodwork).

Key Exclusion criteria for Part 2:

1\. Has developed any concomitant disease (e.g., gastrointestinal, renal, hepatic, endocrine, respiratory, or cardiovascular system disease) or condition or circumstance, or any finding during Part 1/MAD that, in the opinion of the Investigator, makes the participant unsuitable for continued treatment (e.g., could interfere with the conduct of the study or that would pose an unacceptable risk to the participant in this study).

Where it's running

  • Rady Children's Hospital
    San Diego, California, United States
    Recruiting
  • University of Colorado Hopsital - Anschutz Medical Campus
    Aurora, Colorado, United States
    Recruiting
  • Kennedy Krieger
    Baltimore, Maryland, United States
    Recruiting
  • Boston Children's Hospital
    Boston, Massachusetts, United States
    Recruiting
  • Gillette Children's Specialty Healthcare
    Saint Paul, Minnesota, United States
    Recruiting
  • Children's Hospital of Philadelphia
    Philadelphia, Pennsylvania, United States
    Recruiting
Show 6 more locations
  • Vanderbilt University Medical Center
    Nashville, Tennessee, United States
    Recruiting
  • Baylor College of Medicine
    Houston, Texas, United States
    Recruiting
  • Kepler University Hospital
    Linz, Austria
    Recruiting
  • British Columbia Children's Hospital
    Vancouver, Canada
    Recruiting
  • CHU Dijon Bourgogne
    Dijon, France
    Recruiting
  • Hospital Saint Joan de Deu
    Barcelona, Spain
    Recruiting

Study contacts

Similar studies

Other studies for the same condition or treatment. Recruiting studies are listed first.

  • Obudanersen for Angelman Syndrome in UPD/ID patients

    This study tests obudanersen in children and adults with Angelman syndrome caused by UPD or imprinting defects to see if it improves expressive communication.

    Recruiting Phase 3 Ionis Pharmaceuticals, Inc. · Carrboro, North Carolina · NCT07782827

  • Olezarsen for Familial Chylomicronemia Syndrome in kids

    This study tests whether olezarsen given by injection can help children with Familial Chylomicronemia Syndrome.

    Recruiting at 6 sites Phase 3 Ionis Pharmaceuticals, Inc. · Birmingham, Alabama and 5 other locations · NCT07727538

  • Ion775 for high triglyceride levels: safety, tolerability, and how well it works

    A drug called ION775 is being tested to see if it can safely lower fasting triglycerides in adults with hypertriglyceridemia or severe hypertriglyceridemia who are already on standard lipid medicines.

    Recruiting at 17 sites Phase 2 Ionis Pharmaceuticals, Inc. · Lincoln, California and 17 other locations · NCT07604974

  • ION337 safety and tolerability in children with Dravet syndrome

    This will test whether ION337 is safe and well tolerated in children ages 2 to 12 with Dravet syndrome.

    Recruiting at 7 sites Phase 1/2 Ionis Pharmaceuticals, Inc. · Ann Arbor, Michigan and 6 other locations · NCT07531745

  • Donidalorsen for children with hereditary angioedema

    This trial tests if donidalorsen is safe and how it is processed in the body for children aged 2 to under 12 with hereditary angioedema types I or II.

    Recruiting at 18 sites Phase 3 Ionis Pharmaceuticals, Inc. · Santa Monica, California and 17 other locations · NCT07298447

  • Evaluating a new treatment for Pelizaeus-Merzbacher Disease in children

    This study is testing a new drug called ION356 to see if it is safe and tolerable for children with Pelizaeus-Merzbacher Disease who have a specific genetic change.

    Recruiting at 7 sites Phase 1 Ionis Pharmaceuticals, Inc. · Atlanta, Georgia and 6 other locations · NCT06150716

How to take part

  1. Review the eligibility criteria above with your treating physician.
  2. Check the official listing on ClinicalTrials.gov for the latest contact details and recruitment status.
  3. Contact the study coordinator or principal investigator to ask for pre-screening. Pre-screening is free and never obligates you to enroll.
Last reviewed 2026-11-14 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.