Clinical trial NCT06392724: A Study to Evaluate the Safety and Tolerability of GEN6050X in Duchenne Muscular Dystrophy.
Official title: A Single-arm, Open-label, Single-center Study to Evaluate the Safety and Tolerability of Intravenous GEN6050X Gene Therapy in Ambulatory Boys With Duchenne Muscular Dystrophy (DMD).
Study type: INTERVENTIONAL
Overall status: RECRUITING
Phase: EARLY_PHASE1
Conditions: Duchenne Muscular Dystrophy (DMD)
Keywords: Duchenne Muscular Dystrophy
DMD
Gene therapy
Gene editing
Muscular dystrophies
Hereditary neuromuscular disorders
Lead sponsor: Peking Union Medical College Hospital
Sponsor class: OTHER
First posted: 2024-04-30
Enrollment: 3
Sex: MALE
Minimum age (years): 4
Maximum age (years): 10
Standard ages: CHILD
Accepts healthy volunteers: no
Allocation: NA
Intervention model: SINGLE_GROUP
Intervention model description: Single-arm unblinded, single-center study
Primary purpose: TREATMENT

Brief summary: The study will evaluate the safety and tolerability of GEN6050X gene therapy in Duchenne muscular dystrophy (DMD) patients amenable to exon 50 skipping.

Detailed description: GEN6050X is an intravenously administered human DMD exon 50 skipping base editing drug containing dual single-stranded adeno-associated virus serotype 9 (ss.AAV9) vectors.

The study is a first-in-human, single-arm, open-label, single-center clinical trial to evaluate safety and tolerability of a single intravenous infusion of GEN6050X in ambulatory boys with DMD. Other objectives include pharmacokinetics, pharmacodynamics, and the preliminary clinical efficacy of GEN6050X over 52 weeks. A total of three ambulatory pediatric participants (aged 4 to 9 years old) are expected to enroll, each receiving a dose of 5×10\^13 vg/kg. These participants will be dosed in a staggered fashion.

Safety assessments will include monitoring of adverse events (AEs), laboratory tests, electrocardiograms (ECGs), vital signs, and physical examinations throughout the study duration. In addition, a comprehensive short-term prophylactic immunosuppression regimen(including rituximab and sirolimus) will be administered prior to treatment in order to mitigate potential immune response.

Eligibility criteria: Inclusion Criteria:

1. Subject age: 4-10 years old (including 10 years old)
2. Gender: Male
3. Patients with DMD gene exon deletion types confirmed by molecular diagnosis: 8-49, 20-49, 22-49, 51, 51-53, 51-55, 51-57, 51-59, 51-60, 51-67, 51-69, 51-75 or 51-78 and other mutations amenable to exon 50 skipping.
4. The participant is able to walk independently and completes the 10-meter walk test without assistance.
5. Participant is able to complete time to stand from supine independently in less than 30s.
6. The participant is able to cooperate with motor assessment testing.
7. Receipt of glucocorticoids for 6 months and a stable daily dose for at least 12 weeks prior to study entry
8. Ability to tolerate muscle biopsies under anesthesia with no contraindications to these procedures.

Exclusion Criteria:

1. Participants are in the active period of viral infection, including infections such as TORCH virus, Epstein-Barr(EB) virus, and severe acute respiratory syndrome coronavirus 2 (SARS-COV-2).
2. Received a live attenuated vaccine within 3 months prior to receiving GEN6050X, or was exposed to an influenza (or other inactivated) vaccine within 30 days prior to receiving GEN6050X, or received systemic antiviral, anti-infective, and/or interferon therapy.
3. Serological tests found HIV, Hepatitis B Virus(HBV), hepatitis C virus(HCV), and syphilis infection.
4. Severe infection (e.g., pneumonia, pyelonephritis, or meningitis) within 4 weeks prior to receiving gene therapy.
5. With clear symptoms of cardiomyopathy, echocardiography shows that the left ventricular ejection fraction is less than 40%.
6. Need for continuous or intermittent assisted support from a ventilator.
7. Diagnosed with autoimmune disease or receiving related treatment for autoimmune disease.
8. The following indicators are abnormal in laboratory biochemical testing:

   γ-glutamyl transpeptidase (GGT) above the 2-fold upper limit and total bilirubin above 1.5 times the upper limit, cystatin C (cystatin C) \> 1.27 mg/L, hemoglobin (Hgb) \< 100 or \>200 g/L; Leukocytes (WBC) \> 18.5×10\^9/L or platelet ≤ 125×10\^9/L.
9. The titer of AAV9 neutralizing antibody determined by cell suppression assay \> 1:50.
10. Patients have received any gene therapy (e.g., adeno associated virus(AAV) gene therapy), cell therapy (e.g., stem cell transplantation), in vivo editing, or ex vivo editing therapy (e.g., CRISPR-Cas9, TALEN) in the past.
11. Participant has any contraindication to immunosuppressive therapy.
12. Has a medical condition or extenuating circumstance that, in the opinion of the principal investigator, is unsuitable for participation in the clinical trial.
13. The family does not wish to disclose the patient's study participation to the attending physician and other medical providers.

Primary outcomes:
measure: Safety and tolerability of GEN6050X measured by incidence of adverse events (AEs).
timeFrame: through 1 year post-treatment
Secondary outcomes:
measure: Physical Therapy Assessment North Star Ambulatory Assessment (NSAA）
timeFrame: Screening, 6 months-3 Years
measure: Physical Therapy Assessment Time to run/walk 10 meters(TTRW)
timeFrame: Screening, 6 months-3 Years
measure: Physical Therapy Assessment 6MWT
timeFrame: Screening, 6 months-3 Years
measure: Physical Therapy Assessments Change in Time to Stand (TTSTAND)
timeFrame: Screening, 6 months-3 Years
measure: Physical Therapy Assessments Ascend and Descend of 4 steps
timeFrame: Screening, 6 months-3 Years
measure: Physical Therapy Assessments Hand-held dynamometer
timeFrame: Screening, 6 months-3 Years
measure: Physical Therapy Assessments upper limb function
timeFrame: Screening, 6 months-3 Years
measure: Physical Therapy Assessments Pulmonary function
timeFrame: Screening, 6 months-3 Years
measure: Dystrophin protein expression
timeFrame: 24 weeks post-treatment
measure: Serum creatine kinase(CK)
timeFrame: through 1 year post-treatment
Other outcomes:
Locations:
city: Beijing
country: China
facility: Peking Union Medical College Hospital
Study officials:
References:
citation: Yuan J, Ma Y, Huang T, Chen Y, Peng Y, Li B, Li J, Zhang Y, Song B, Sun X, Ding Q, Song Y, Chang X. Genetic Modulation of RNA Splicing with a CRISPR-Guided Cytidine Deaminase. Mol Cell. 2018 Oct 18;72(2):380-394.e7. doi: 10.1016/j.molcel.2018.09.002. Epub 2018 Oct 4.