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
| Phase | Phase1; Phase2 |
|---|---|
| Study type | Interventional |
| Ages | 2 Years to 65 Years |
| Sex | Men only |
| Enrollment | 48 (estimated) |
| Sponsor | Ionis Pharmaceuticals, Inc. Industry-sponsored |
| Locations | 12 sites (San Diego, California and 11 other locations) |
| Status | Recruiting |
| Started | October 21, 2024 |
| Main results expected | September 2027 |
| Study ends | April 2030 |
| Registry record updated | October 8, 2026 |
| Trial ID | NCT06430385 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
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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
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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
- Study coordinator: Ionis Pharmaceuticals
- Email: IonisMECP2study@clinicaltrialmedia.com
- Phone: (844) 779-1497
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How to take part
- Review the eligibility criteria above with your treating physician.
- Check the official listing on ClinicalTrials.gov for the latest contact details and recruitment status.
- Contact the study coordinator or principal investigator to ask for pre-screening. Pre-screening is free and never obligates you to enroll.