Actively Recruiting
A Multi-Center, Open-label, Phase 1/2 Trial of the Safety and Efficacy of MVX-220 Gene Therapy Administered by Intra-Cisterna Magna Injection to Participants With Angelman Syndrome
Led by MavriX Bio, LLC · Updated on 2026-03-16
12
Participants Needed
3
Research Sites
165 weeks
Total Duration
On this page
AI-Summary
What this Trial Is About
Researchers are evaluating the safety and effectiveness of MVX-220 gene therapy in children and adults with Angelman syndrome who have specific genetic types: UBE3A gene deletion, uniparental disomy, or imprinting center defect. The study is a Phase 1/2 trial designed to assess how well this gene replacement therapy works and its tolerability in these participants. Angelman syndrome is a genetic condition caused by problems with the UBE3A gene, and MVX-220 aims to provide a functional copy of this gene. Participants receive a single dose of MVX-220 through an injection into the cisterna magna, a fluid space near the brain. The study includes two main groups: adults aged 18 to 50 years and children aged 4 to 8 years. There is also an optional third group that may include both adults and children aged 4 to 50 years. Before and briefly during the study, participants take steroids to reduce immune reactions to the gene therapy. An independent board reviews safety data after adults are treated before children enroll. Throughout the study, participants are monitored for safety and treatment effects for two years after receiving the gene therapy, followed by a longer, less frequent follow-up period lasting three more years, totaling five years of observation. Researchers assess adverse events and measure changes in communication, development, behavior, mobility, sleep, quality of life, viral DNA levels, and brain activity using various scales, wearable devices, diaries, and EEG tests. Regular clinical exams, lab tests, and vital sign checks are also performed to track safety.
CONDITIONS
Brief Title
A Phase 1/2 Study of the Safety and Efficacy of MVX-220 in Angelman Syndrome
Who Can Participate
Eligibility Criteria
You may qualify if you...
- Participant's parent or legal guardian must provide written informed consent.
- Diagnosis of Angelman syndrome with genetic confirmation of one of the following: full maternal UBE3A gene deletion at 15q11.2-q13, uniparental disomy, or imprinting center defect.
- Age 18 to 50 years for adults or 4 to 8 years for children at screening.
- Ability to walk independently.
- Stable antiepileptic medication use with no changes within 1 month prior to screening, except for weight-related dose adjustments.
You will not qualify if you...
- Any significant medical condition other than Angelman syndrome making participation unsuitable.
- Laboratory abnormalities such as elevated liver enzymes, abnormal bilirubin, gamma-glutamyl transferase, low kidney function, low hemoglobin, abnormal white blood cell or platelet counts, or abnormal clotting tests.
- Known personal or family history of hemophagocytic lymphohistiocytosis, macrophage activation syndrome, multisystem inflammatory syndrome, complement disorders, or complement gene mutations.
- History of severe autoimmune diseases including systemic lupus erythematous, Still's disease, or rheumatoid arthritis.
- History of thrombotic microangiopathy, microangiopathic hemolytic anemia, or hypercoagulable conditions such as deep vein thrombosis or pulmonary embolism.
- Current treatment with high dose immunosuppressants.
- Prior investigational drug use within 6 months or 5 half-lives before hospital admission.
- Prior antisense oligonucleotide treatment within 1 year before hospital admission.
- History of gene therapy.
- Contraindications to intra-cisterna magna injection, including imaging, contrast, anesthesia risks, or increased adverse outcome risk.
- Contraindications to glucocorticoid use.
AI-Screening
AI-Powered Screening
Complete this quick 3-step screening to check your eligibility
Your Study Journey
Duration - 2 to 4 weeks
Participants are screened for eligibility to participate in the trial.
1 visit (in-person)
Duration - Single dose with steroid treatment before and briefly during the study
Participants receive a single dose of MVX-220 gene therapy administered by injection into the cisterna magna and take steroids before and briefly during the study to help reduce immune response.
1 treatment visit (in-person)
Duration - Up to 5 years post-treatment
Participants are followed for safety and efficacy for an initial 2-year period post-treatment, then continue with less frequent monitoring for an additional 3 years.
Regular visits over 2 years, then less frequent visits for 3 additional years
Trial Site Locations
Total: 3 locations
1
Cedars-Sinai Medical Center
Los Angeles, California, United States, 90048
Actively Recruiting
2
Rush University Medical Center
Chicago, Illinois, United States, 60612
Actively Recruiting
3
Boston Children's Hospital
Boston, Massachusetts, United States, 02115
Actively Recruiting
Research Team
M
MavriX Bio, LLC
How is the study designed?
Study Type
INTERVENTIONAL
Masking
NONE
Allocation
NON_RANDOMIZED
Model
SINGLE_GROUP
Primary Purpose
TREATMENT
Number of Arms
3
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