Skip to content
Clinical Trials – home

Rare diseases

Investigational molecules

Locations

Our offerNewsroom

RecruitingRare disease

Study on the Safety and Effects of ION440 for Patients with MECP2 Duplication Syndrome

Verified siteInvestigationalNo placebo
Clinical Trials Concierge

Prefer not to search? Our Concierge searches the trials for you.

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 rare genetic condition known as MECP2 Duplication Syndrome. This condition is caused by having an extra copy of the MECP2 gene, which can lead to various developmental and neurological issues. The study will use a treatment called ION440, which is administered through an injection into the spinal canal, a method known as intrathecal use. The purpose of the study is to evaluate the safety and tolerability of this treatment in patients with MECP2 Duplication Syndrome.

The study is designed to be conducted in two parts. In the first part, participants will receive multiple doses of ION440 to assess how their bodies respond to the treatment. This includes monitoring for any side effects and changes in health indicators such as vital signs and neurological function. The second part of the study will continue to monitor participants who have completed the first part, ensuring that the treatment remains safe and well-tolerated over a longer period.

Throughout the study, researchers will collect information on how ION440 is processed in the body, including its concentration in the blood and spinal fluid. This will help determine the appropriate dosage and frequency of administration. The study aims to provide valuable insights into the potential benefits and risks of using ION440 as a treatment for MECP2 Duplication Syndrome, ultimately contributing to better management of this condition.

The research process

The trial runs in 6 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Initial assessment

    Upon joining the study, an initial assessment is conducted to confirm eligibility. This includes verifying a documented diagnosis of MECP2 Duplication Syndrome (MDS) and ensuring stable doses of any current medications for at least three months prior to the baseline.

    Participants must be males aged between 2 and 65 years, depending on the specific group. A parent or caregiver must be available to provide informed consent and attend all study visits.

  2. Step 2

    Part 1: treatment initiation

    Participants begin receiving the study drug, ION440, administered via intrathecal injection. This means the medication is injected into the space around the spinal cord.

    The study is double-blind, meaning neither the participants nor the researchers know who receives the actual drug or a sham treatment. The goal is to evaluate the safety and tolerability of the drug.

  3. Step 3

    Monitoring and assessments

    Throughout the study, participants undergo regular monitoring. This includes checking vital signs, physical and neurological examinations, laboratory assessments, and electrocardiograms (ECG).

    The primary focus is on identifying any treatment-emergent adverse events and significant changes from the baseline.

  4. Step 4

    Pharmacokinetic analysis

    The study also involves measuring the concentration of ION440 in the blood and cerebrospinal fluid (CSF) to understand how the drug is processed in the body.

    Key measurements include the maximum plasma concentration, area under the concentration-time curve, elimination half-life, and pre-dose and post-treatment concentrations.

  5. Step 5

    Part 2: continuation for completers

    Participants who complete Part 1 and meet all criteria continue to Part 2. This phase involves further administration of ION440 and continued monitoring.

    No new screening bloodwork is required for Part 2, as all criteria from Part 1 apply.

  6. Step 6

    Study completion

    The study is estimated to conclude by April 22, 2030. Participants will have contributed valuable data on the safety and effects of ION440 in treating MECP2 Duplication Syndrome.

Who can join the trial?

7 criteria

  • Participants must be males aged between 2 and 65 years old, depending on the specific group they are in.
  • Participants must have at least one parent or caregiver who is 18 years or older, capable of giving informed consent, attending all study visits, and providing feedback about the participant's symptoms and performance.
  • Participants must have a documented diagnosis of Methyl CpG binding protein 2 (MECP2) Duplication Syndrome (MDS), confirmed by genetic testing.
  • Participants must be able to complete all study procedures, measurements, and visits, and have supportive social circumstances, as judged by the study doctor.
  • Participants must be on stable doses of any other medications they are taking for at least 3 months before the study begins.
  • For Part 2 of the study, participants must have completed Part 1, which means they received at least one dose of the study drug and attended all study visits through the follow-up.
  • All criteria from Part 1 also apply to Part 2, but participants will not need to undergo new blood tests for screening.

Who cannot join the trial?

3 criteria

  • Individuals who do not have a diagnosis of Methyl CpG binding protein 2 (MECP2) Duplication Syndrome (MDS) cannot participate. This is a specific genetic condition.
  • Females are not eligible to participate in this study.
  • Individuals who are not considered part of a vulnerable population are excluded. A vulnerable population includes groups that may need special protection or care.
Clinical Trials Concierge

Prefer not to search? Our Concierge searches the trials for you.

Tell us about your condition – we search every trial in Europe and connect you with the right site.

We usually reply within a few days

Verified sites

All sites with verified contact details – recruitment status may not be available; ask directly

Trial locations

Where you can join this trial

Countries are shaded by recruitment status. Click a recruiting country to ask about joining there.

Recruiting
Not finding your country?

Not sure what to do next?

Joining a clinical trial can seem overwhelming. We guide you step by step, so you know exactly what to expect and how we support you through the process.

See the full process and FAQ

Investigated drugs

ION440 is a medication being studied for its safety and tolerability in patients with MECP2 Duplication Syndrome. It is administered intrathecally, which means it is delivered directly into the spinal canal. The study aims to understand how the body processes the medication and its effects on the body.

What is already known about the treatment

ION440 – This medication is administered intrathecally, meaning it is injected into the spinal canal. It is currently being studied in clinical trials for its safety and tolerability in treating MECP2 Duplication Syndrome, a rare genetic disorder. The main therapeutic indication is to address symptoms associated with this syndrome. At the molecular level, ION440 is designed to target and reduce the effects of the duplicated MECP2 gene, which is responsible for the condition. It falls under the pharmacological classification of gene therapy agents.

Investigated diseases

Methyl CpG Binding Protein 2 (MECP2) Duplication Syndrome – This is a rare genetic disorder caused by the duplication of the MECP2 gene on the X chromosome. It primarily affects males and leads to a range of developmental and neurological symptoms. Individuals with this syndrome often experience intellectual disability, delayed speech and motor skills, and recurrent respiratory infections. The condition can also cause seizures, low muscle tone, and autistic-like behaviors. Symptoms typically appear in early childhood and can vary in severity among affected individuals. The progression of the disease is generally characterized by a gradual worsening of neurological and developmental symptoms over time.
Trial detailsLast updated 7 Oct 2026
Age18+ yearsPhasePhase I/IITrial ID2023-507192-22-00Protocol codeION440-CS1Estimated enrolment52 patientsSponsorIonis Pharmaceuticals Inc.

sourced from the EU Clinical Trials Register and site verification

Want to learn more about this trial or check if you can participate?

Clinical Trials Concierge

Prefer not to search? Our Concierge searches the trials for you.

Tell us about your condition – we search every trial in Europe and connect you with the right site.