Clinical Research Alert: Phase 1/2 Study of SGT-003 in Boys with DMD

Researchers at Solid Biosciences are seeking boys with Duchenne muscular dystrophy (DMD) to participate in a phase 1/2 clinical trial (INSPIRE DUCHENNE) to evaluate the safety and efficacy of the investigational gene therapy (SGT-003). DMD is caused by the loss of the dystrophin protein, which is important for the structure and function of muscle cells. SGT-003 is a gene therapy designed to introduce a shortened, functional dystrophin protein (microdystrophin) into the body for the treatment of DMD. The current study is examining whether this treatment can increase the levels of microdystrophin, and potentially slow the loss of function, in people with DMD.

The study

This is a multicenter, open-label, non-randomized study. This means that all participants, at multiple study sites, will receive SGT-003 treatment. There are five cohorts in the study, which are each primarily based on age. The total duration of the study for each participant will be five years. For the first 30 days following treatment, participants will have frequent visits to the hospital for check-ups and bloodwork to monitor safety. Visits will become less frequent over the next two months and then continue to be every three months for the first year of the study. Following this period, the check-ups will be every 6 to 12 months over the remainder of the five-year study period.

The drug will be administered as a single intravenous (in the vein) infusion. The effects of SGT-003 will be evaluated using a number of tests and procedures including but not limited to: safety testing, muscle biopsies (at screening, 90 days, and 360 days for evaluation of microdystrophin expression), and functional assessments to monitor changes in disease progression over time.

Study criteria

The following cohorts are currently enrolling participants:

• Cohort 1: 4 to < 7 years of age, ambulatory
• Cohort 2: 7 to < 12 years of age, ambulatory
• Cohort 3: 0 to < 4 years of age, ambulatory or non-ambulatory

The following cohorts are planned but are not currently enrolling participants. Initiation of participant enrollment in Cohorts 4 and 5 will be subject to the accrual of safety and efficacy data from Cohorts 1-3.

• Cohort 4: 12 to < 18 years of age, ambulatory
• Cohort 5: 10 to < 18 years of age, non-ambulatory

In addition to age and ambulatory status, individuals must meet the following eligibility criteria:

• Diagnosis of DMD, excluding those with any deletion mutation in exons 1 to 11 and/or exons 42 to 45, inclusive, in the DMD gene

• On a stable daily steroid regimen for at least 12 weeks (except for Cohort 3)
• At least 12 weeks since last having received an exon-skipping therapy, vamorolone, and/or givinostat
• Negative for AAV antibodies
• Additional functional and safety criteria based on age

Individuals may not be eligible to participate if they are affected by another condition or receiving another treatment that might interfere with the ability to undergo safe testing.

Please visit the ClinicalTrials.gov posting for this study (NCT06138639) at this link for additional information and study locations.

Interested in participating?

Travel support will be available for eligible participants and their caregivers.

To learn more about the study or inquire about participation, contact the Solid Biosciences’ team at ClinicalTrials@solidbio.com or reach out to the contacts listed under study locations in the ClinicalTrials.gov posting.