Pitt Hopkins SyndromePhase 1/2NCT07135050
Phase 1/2 Study of MZ-1866, an AAV-9 Gene Therapy Delivered by Intracerebroventricular Injection to Participants With Pitt Hopkins Syndrome
A Phase 1/2 study testing MZ-1866 in people with Pitt Hopkins Syndrome, run by Mahzi Therapeutics at 4 sites in 2 countries.
Trial summary
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… Read more about this study
- Who is it for?
- Ages 2 to 25 years
- Conditions the study is for
- Pitt Hopkins Syndrome
- What is being tested?
- MZ-1866
- Type of treatment
- Injection or infusion
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 12 participants
- Where
- 4 sitesin 2 countries
- Study dates
- 19 Dec 2025to Jul 2029
- Phase
- Phase 1/2
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 2 to 25 years
- All sexes
- No healthy volunteers
- Child, Adult
Who may be able to join
- 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
Who cannot join
- 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
Trial locations and contacts
4 sites in 2 countries. Contact the study team or a site near you to ask about taking part.
4 sites in 2 countries
United States3 sites, 3 recruiting
- Recruiting
Children's Hospital Colorado
Aurora, Colorado, 80045
Sky Gould, sky.gould@childrenscolorado.org
Diana Walleigh, MD
- Recruiting
Rush University Medical Center
Chicago, Illinois, 60612
Tara Khandelwal, Mehr_Khandelwal@rush.edu
Elizabeth Berry-Kravis, M.D., Ph.D.
- Recruiting
UCSF Benioff Children's Hospital Oakland
Oakland, California, 94609
Neil Smith, neil.smith2@ucsf.edu
Alex Fay, M.D., Ph.D.
Israel1 site, 1 recruiting
- Recruiting
Sheba Medical Center
Tel HaShomer
Ester Frank, 972-52-629-0473, Ester.Frank@sheba.health.gov.il
Gali Heimer, M.D., Ph.D.
About this study
Official title: 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
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:
Read more
- 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
- Conditions
- Pitt Hopkins Syndrome
- Being tested
- MZ-1866
- Keywords
- MZ-1866, AAV9 Gene Therapy, Gene Therapy, ICV, Intracerebroventricular, TCF4, PTHS
- Medical subject headings
- Pitt-Hopkins syndrome
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
MZ-1866Genetic
AAV-9 gene therapy delivered by intracerebroventricular injection
| Study group | Role | What they receive |
|---|---|---|
| Cohort 1 (MZ-1866) | Experimental | Participants ages 12-25 years Receives: Genetic: MZ-1866 |
| Cohort 2 (MZ-1866) | Experimental | Participants aged 2-11 years Receives: Genetic: MZ-1866 |
What is being measured
The primary outcome is the main question the study is designed to answer.
To evaluate the safety and tolerability of MZ-1866 in participants with Pitt Hopkins Syndrome
Frequency and severity of adverse events of special interest
Measured: Week 104
Secondary outcomes (2)
To evaluate the safety and tolerability of MZ-1866 in participants with Pitt Hopkins Syndrome
Frequency and severity of adverse events
Measured: Week 104
To further assess the safety and tolerability of MZ-1866 in participants with Pitt Hopkins Syndrome
Frequency of clinically significant physical examination findings, vital signs, laboratory tests and electrocardiograms that are considered outside normal range.
Measured: Week 104
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted21 Aug 2025
- Study start19 Dec 2025
- Primary completionMar 2029 (estimated)
- Study completionJul 2029 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Pitt Hopkins SyndromeStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 1/2
- Primary purpose
- Treatment
- Allocation
- Non-randomised
- Intervention model
- Sequential
- Masking
- None (open label)
- Enrolment
- 12 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Mahzi Therapeutics
- Sponsor type
- Industry (pharma, biotech, devices)
- Collaborators
- California Institute for Regenerative Medicine (CIRM)
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07135050
- Sponsor's protocol ID
- MZ1866-CL101
- Status last verified
- Jul 2026
- First submitted
- 4 Aug 2025
- Last updated
- 31 Jul 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- Undecided
Study at a glance
From the registry record, last updated by the sponsor on 31 Jul 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- 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
- ClinicalTrials.gov ID
- NCT07135050
- Acronym / sponsor ID
- MZ1866-CL101
- Conditions
- Pitt Hopkins Syndrome
- Keywords
- MZ-1866, AAV9 Gene Therapy, Gene Therapy, ICV, Intracerebroventricular, TCF4, PTHS
- Phase
- Phase 1/2
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 12 participants (estimated)
- Lead sponsor
- Mahzi TherapeuticsIndustry (pharma, biotech, devices)
- Collaborators
- California Institute for Regenerative Medicine (CIRM)
- Study start
- 19 Dec 2025 (actual)
- Primary completion
- Mar 2029 (estimated)
- Study completion
- Jul 2029 (estimated)
- First posted
- 21 Aug 2025 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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
Study design
- Primary purpose
- Treatment
- Allocation
- Non-randomised
- Intervention model
- Sequential
- Masking
- None (open label)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Cohort 1 (MZ-1866) | Experimental | Genetic: MZ-1866Participants ages 12-25 years |
| Cohort 2 (MZ-1866) | Experimental | Genetic: MZ-1866Participants aged 2-11 years |
Who may qualify
- Ages
- 2 to 25 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Child, Adult
Key inclusion criteria (3 listed)
- 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
Key exclusion criteria (6 listed)
- 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
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| MZ-1866AAV-9 gene therapy delivered by intracerebroventricular injection | Genetic | Cohort 1 (MZ-1866), Cohort 2 (MZ-1866) |
Primary outcome
To evaluate the safety and tolerability of MZ-1866 in participants with Pitt Hopkins Syndrome
Time frame: Week 104
Frequency and severity of adverse events of special interest
2 secondary outcomes
To evaluate the safety and tolerability of MZ-1866 in participants with Pitt Hopkins Syndrome
Time frame: Week 104
To further assess the safety and tolerability of MZ-1866 in participants with Pitt Hopkins Syndrome
Time frame: Week 104
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 31 Jul 2026.
- Individual participant dataSharing planned: Undecided
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
4 sites in 2 countries: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 1/2 study testing MZ-1866 in people with Pitt Hopkins Syndrome, run by Mahzi Therapeutics at 4 sites in 2 countries.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 3 inclusion and 6 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 31 Jul 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 4 sites in United States, Israel. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this combined phase mean?
Phase 1 studies test a treatment in a small group of people for the first time or in a new way, mainly to check safety and find the right dose.
Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Emily Radomile (1-844-446-2494, clinicaltrials@mahzi.com), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
To evaluate the safety and tolerability of MZ-1866 in participants with Pitt Hopkins Syndrome (time frame: Week 104). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 31 Jul 2026.