Phase 1/2 Study of FRF-001, an AAV-9 Gene Therapy, in Patients With FOXG1 Syndrome (FS)

July 23, 2026 updated by: FOXG1 Research Foundation

An Open-Label First-in-Human Phase 1/2 Study to Evaluate the Safety, Tolerability, and Efficacy of FRF-001, an AAV-9 Gene Therapy Administered by Intracerebroventricular Injection in Participants With FOXG1 Syndrome

The goal of this clinical trial is to learn if FRF-001 is a safe, tolerable, and efficacious treatment for children and adults with FOXG1 syndrome.

Study Overview

Status

Enrolling by invitation

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Estimated)

12

Phase

  • Phase 2
  • Phase 1

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • United States
    • Texas
      • Houston, Texas, United States, 77030
        • Texas Children's Hospital (Baylor College of Medicine)

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Child
  • Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Participant must have a FOXG1 mutation confirmed as likely pathogenic or pathogenic by whole exome sequencing, whole genome sequencing, gene panel, single gene testing, or microarray performed at an accredited lab, with clinical phenotype consistent with FS in the opinion of the investigator.
  • The participant, or the participant's parent or legal guardian, is registered at the time of signing the informed consent in the FRF Citizen Natural History Study.
  • The participant, or the participant's parent, legal guardian, or caregiver are willing and able to complete all aspects of the study, adhere to the study visit schedule, and comply with all assessments.

Exclusion Criteria:

  • Another genetic mutation or clinical comorbidity which could potentially confound the typical FOXG1 syndrome phenotype; FOXG1 gene duplication; or FOXG1 gene deletions that include regions outside of the FOXG1 coding region.
  • Prior treatment with a gene, cell therapy, or investigational treatment for FS.
  • Concurrent enrollment in another clinical study unless it is observational (noninterventional) and the study that does not interfere with the requirements of the current protocol and does not have the potential to impact the evaluation of safety or efficacy of FRF-001.
  • Any current or prior condition or contraindication that would render the participant unable to safely receive prophylactic corticosteroids, as assessed and determined by the Investigator.
  • Contraindications to or unwilling to undergo MRI or lumbar puncture (LP) procedures.
  • Any medical condition, comorbidity, or anatomical abnormality that, in the opinion of the Investigator and/or the attending anesthesiologist, would contraindicate the safe administration of sedation or general anesthesia required for study procedures.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Treatment
Genetic: FRF-001
AAV-9 gene therapy delivered by intracerebroventricular injection

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
To evaluate the safety and tolerability of single-dose FRF-001 in participants with FOXG1 syndrome
Time Frame: Through Week 104
Incidence, severity, and causality of treatment-emergent adverse events (TEAEs), treatment-emergent serious adverse events (TESAEs), and adverse events of special interest (AESIs)
Through Week 104
To evaluate the efficacy of single-dose FRF-001 in participants with FOXG1 syndrome
Time Frame: Week 52 and Week 104
Attainment of motor milestones, as assessed by the Peabody Developmental Motor Scales - Third Edition (PDMS-3)
Week 52 and Week 104

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

FOXG1 Research Foundation

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

July 20, 2026

Primary Completion (Estimated)

July 1, 2029

Study Completion (Estimated)

December 1, 2029

Study Registration Dates

First Submitted

December 16, 2025

First Submitted That Met QC Criteria

December 17, 2025

First Posted (Actual)

December 19, 2025

Study Record Updates

Last Update Posted (Actual)

July 24, 2026

Last Update Submitted That Met QC Criteria

July 23, 2026

Last Verified

July 1, 2026

More Information

Terms related to this study

Other Study ID Numbers

  • FRF-001-CL101

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

UNDECIDED

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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