ClinicalTrials.gov record NCT07135050

Phase 1/2 Study of MZ-1866, an AAV-9 Gene Therapy Delivered by Intracerebroventricular Injection to Participants With Pitt Hopkins Syndrome

Record copied from ClinicalTrials.gov: Oct 10, 2026AI summaries generated: Jul 27, 2026

Phase 1/2 First-in-Human Study to Evaluate the Safety, Tolerability, and Efficacy of MZ-1866, an AAV-9 Gene Therapy Delivered by Intracerebroventricular Injection to Participants With Pitt Hopkins Syndrome

StatusRecruitingThe study is currently enrolling participants. Only the study team can say whether a particular person can join.
Study typeInterventionalA study in which researchers assign participants to one or more interventions, such as a drug, procedure, device, behavioural programme or other approach, to measure their effects.
PhasePhase 1/2A study that combines safety and dose-finding (phase 1) with a first look at whether the treatment has an effect (phase 2).
Age2 years old to 25 years old
SexAll
LocationIsrael, United States
AI summaryWhat this study is about, in plain languageShow ▾Hide ▴

AI-written from the registry record, not the study's own wording. May contain errors or omissions. Check the registry text on this page and the original record ↗ before acting on it.

This Phase 1/2 study gives a single intracerebroventricular (ICV) dose of MZ-1866 to children and young people with Pitt Hopkins Syndrome. The main goal is to learn whether the treatment is safe and tolerable; participants will have regular exams, lab tests, ECGs, and neurodevelopmental assessments. Caregivers will be interviewed and asked to keep diaries and complete questionnaires about symptoms and development.

What it is studying. Whether a single ICV dose of MZ-1866 is safe and tolerable in people with Pitt Hopkins Syndrome, and to collect safety data (adverse events, exam/lab/ECG findings) alongside neurodevelopmental and caregiver-reported measures.

What the researchers hope to learn. To evaluate the safety and tolerability of MZ-1866 in participants with Pitt Hopkins Syndrome and to collect data on adverse events, clinical findings, and developmental measures through the planned follow-up period (primary safety assessments noted through Week 104).

What this study is about

The study's own summary, as published on ClinicalTrials.gov. Underlined terms have a short explanation.

The goal of this clinical trial is to learn if MZ-1866 is a safe and tolerable treatment for children and adults with Pitt Hopkins Syndrome. To evaluate the safety of MZ-1866, the following will be evaluated:

  • frequency and severity of adverse events
  • physical exam, laboratory results and electrocardiogram findings

Participants will:

  • receive a single dose of MZ-1866 by intracerebroventricular injection
  • be seen by the study physician and site staff periodically to assess changes to their health status
  • be periodically evaluated using neurodevelopmental tools

Caregivers will:

  • be interviewed periodically about the health status and development of the participant
  • keep diaries and complete periodic questionnaires regarding participant symptoms

Interventions being studied

Being studied in this trial does not mean the treatment or procedure is approved or available for this condition.

Genetic
  • MZ-1866

Eligibility

The criteria exactly as listed on ClinicalTrials.gov. Only the study team can say whether they apply to you.

Inclusion criteria

  • The participant has a TCF4 gene mutation confirmed as "pathogenic" or "likely pathogenic" by whole exome sequencing, whole genome sequencing, gene panel, single gene testing, or microarray, performed at an accredited laboratory
  • Clinical phenotype consistent with Pitt Hopkins Syndrome, in the opinion of the investigator
  • The participant, or the participant's parent or legal guardian, is willing to provide access to prior medical records for the collection of demographics and diagnostic and treatment history

Exclusion criteria

  • A deletion that includes the TCF4 gene that is over 12 Mbp in size
  • Another genetic mutation or clinical comorbidity not associated with Pitt Hopkins Syndrome that could potentially confound interpretation of the study data
  • A central nervous system structural or vascular abnormality that is a contraindication to the ICV administration procedure, including but not limited to: signs or symptoms of increased intracranial pressure, history of a space-occupying lesion, or presence of a ventricular shunt that would preclude ICV procedures or safety assessments, or increase risk to the participant
  • Not able to receive prophylactic corticosteroids due to a medical contraindication or participant has a history of a condition that could worsen with corticosteroid therapy as assessed and determined by the Investigator
  • Not able to undergo MRI procedures
  • Cannot be anesthetized for the ICV injection

Study description and what participation involves

The registry record has no detailed description beyond the summary above.

AI summaryWhat participation may involve, in plain languageShow ▾Hide ▴

AI-written from the registry record, not the study's own wording. May contain errors or omissions. Check the registry text on this page and the original record ↗ before acting on it.

Receive a single dose of MZ-1866 delivered by an intracerebroventricular (ICV) injection (this requires anesthesia). Have regular study visits for safety monitoring (physical exams, blood tests, electrocardiograms and likely MRI scans) and periodic neurodevelopmental assessments. Caregivers will be interviewed periodically, keep symptom diaries, and complete questionnaires. Safety and tolerability will be followed over the study period (primary outcome assessments reported through Week 104).

How the study is structured. An open-label, non-randomized Phase 1/2 trial run in sequence with two age-based cohorts (ages 12–25 and 2–11). Each participant receives one ICV injection of MZ-1866 and is followed with periodic clinic visits for safety checks, developmental evaluations, and caregiver questionnaires. There is no masking; all participants receive the study treatment.

Questions you could ask

These questions are suggestions for a conversation with the study team or your own clinician, not advice.

  • This is an early-phase study, mainly about safety and dose. What is already known about this treatment?
  • The listed sites are in Israel, United States. Is any of them reachable for me, and does the study help with travel?
  • Which of the eligibility criteria would need to be checked with tests before I could join?

More on Pitt-Hopkins syndrome

Clinical trials3 trials listed for Pitt-Hopkins syndromeEvery trial the registry lists for Pitt-Hopkins syndrome, with recruitment status, phase and sites, updated from ClinicalTrials.gov.See all trials →Research updatesWhat changed in Pitt-Hopkins syndrome researchLatest monthly update: September 2026. Includes: Gut movement. New research summarized each month in plain language, with links to every source paper.Read the latest update →

Important dates

Study start
Dec 19, 2025
Primary completion
March 2029 (estimated)
Study completion
July 2029 (estimated)
Target enrollment
12 participants (estimated)
Last updated on registry
Jul 31, 2026
Data verified
Oct 10, 2026

Sponsor and research team

The lead sponsor funds and oversees the trial. A pharmaceutical or biotech company sponsor typically means the study is testing that company's drug or device; a hospital, university, or government agency usually indicates investigator-initiated or publicly funded research.

Lead sponsor
Mahzi Therapeutics
Collaborators
  • California Institute for Regenerative Medicine (CIRM)

Central study contact

If you're interested in participating, the central contact can answer general questions about the study — including eligibility requirements and how to find a recruiting site near you. Actual eligibility is determined by the site's medical team.

Participating sites (4)

Terms used on this page · explanations by MedicalUpdates.ai

adverse events
Any unwanted medical problem that happens during a study, whether or not it was caused by the treatment. A 'serious' adverse event is one that meets specific criteria, such as causing death, being life-threatening, requiring or prolonging hospital admission, causing significant disability, or another medically important outcome.
electrocardiogram
A recording of the heart's electrical activity. QTc is one measurement from it; some drugs are avoided if it is prolonged.
intracerebroventricular
Given directly into the fluid-filled spaces (ventricles) inside the brain, usually through an implanted catheter or reservoir.
legal guardian
A person who is legally allowed to make decisions, including consent to research, on behalf of someone who cannot consent for themselves.
contraindication
A reason a particular test or treatment should not be used for a person, for example a metal implant that rules out an MRI scan.
corticosteroids
Steroid medicines, such as prednisone, that reduce inflammation. Studies often require a stable dose at entry or measure whether the study treatment allows the dose to be reduced.
MRI
A scan that uses magnets and radio waves, not X-rays, to make detailed pictures of the inside of the body. Some implants and metal objects mean a person cannot have one.
Inclusion Criteria
The conditions a person must meet to be considered for the study, for example a confirmed diagnosis, an age range or a test result.
Exclusion Criteria
The conditions that rule a person out even if they meet the inclusion criteria, for example other illnesses, certain medicines or pregnancy.

The study record on this page is reproduced from ClinicalTrials.gov, a database of the U.S. National Library of Medicine, where it was submitted by the study sponsor. MedicalUpdates.ai does not own this content, is not affiliated with or endorsed by ClinicalTrials.gov, NIH, or the U.S. Government, and does not verify the record. Plain-language notes, the glossary and the questions above are added by this site; text in the boxes marked "AI summary" was written by an AI model and may contain errors. Registry records change over time. Check the original record for the current version and discuss eligibility or participation with a qualified healthcare professional.

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