A Study of SGT-003 Gene Therapy in Duchenne Muscular Dystrophy (INSPIRE DUCHENNE)

About

Brief Summary

This is a multicenter, open-label, non-randomized study to investigate the safety, tolerability, and efficacy of a single intravenous (IV) infusion of SGT-003 in participants with Duchenne muscular dystrophy. There will be 5 cohorts in this study. Cohort 1 will include participants 4 to < 7 years of age. Cohort 2 will include participants 7 to < 12 years of age. Cohort 3 will include participants 0 to < 4 years of age. Cohort 4 will include participants 12 to < 18 years of age. Cohort 5 will include participants 10 to < 18 years of age. Initiation of participant enrollment in Cohorts 4 and 5 will be subject to the accrual of safety and efficacy data from Cohorts 1-3. All participants will receive SGT-003 and will be enrolled in the study for 5 total years for long-term follow up.

Primary Purpose

Treatment

Study Type

Interventional

Phase

Phase 1/Phase 2

Eligibility

Gender

Male

Healthy Volunteers

No

Minimum Age

0 Years

Maximum Age

17 Years

Inclusion Criteria:

Cohort 1: 4 to <7 years of age
Cohort 2: 7 to <12 years of age
Cohort 3: 0 to < 4 years of age
Cohort 4: 12 to < 18 years of age
Cohort 5: 10 to < 18 years of age
Participant ambulatory status at the time of Screening Part A or Rescreening, as defined by the ability to complete a 10-meter walk/run test in < 30 seconds:
- Cohorts 1, 2, and 4: Ambulatory
- Cohort 3: Either ambulatory or non-ambulatory
- Cohort 5: Non-ambulatory, but having been previously ambulatory by history
Established clinical diagnosis of DMD and documented dystrophin gene mutation predictive of DMD phenotype confirmed by Sponsor genetic testing. In cases where a genotype may be predictive of residual dystrophin production and/or a clear clinical diagnosis of DMD cannot be made (e.g., due to age), evaluation of dystrophin levels in baseline muscle biopsies may be required to determine eligibility under this criterion.
Negative for AAV antibodies.
Steroid regimen:
- Cohorts 1, 2, 4, and 5: A stable daily oral steroid regimen of at least 0.5 mg/kg/day of prednisone or 0.75 mg/kg/day of deflazacort for ≥12 weeks prior to Screening Part A or Rescreening, allowing for weight-based modifications consistent with clinical practice.
- Cohort 3: N/A
Meet 10-meter walk/run time criteria
Meet time to rise from supine criteria
Cohort 5: Meet Performance of Upper Limb (PUL) 2.0 criteria
Participant has body weight: ≤ 90 kg

Exclusion Criteria:

Treatment with dystrophin modifying drugs within 3 months prior to screening.
Current or prior treatment with an approved or investigational gene transfer drug.
Exposure to certain approved or investigational drugs within 3 months prior to screening or 5 half-lives since last administration, whichever is longer.
Established clinical diagnosis of DMD that is associated with any deletion mutation in exons 1 to 11 or 42 to 45, inclusive, in the DMD gene as documented by a genetic report and confirmed by Sponsor genetic testing.