2-year Data for Duchenne Muscular Dystrophy Gene Therapy Shows Durable Improvements

SGT-001, Solid Biosciences’ investigational gene therapy for treating Duchenne muscular dystrophy (DMD), improved outcomes in treated patients over 2 years, according to new data from the phase 1/2 IGNITE-DMD study (NCT03368742).^1,2

Updated 2-year data from the first 3 patients treated in the high-dose cohort (2E14vg/kg) were presented at the 2022 Muscular Dystrophy Association (MDA) Clinical and Scientific Conference, March 13-16, in Nashville, Tennessee, by Roxana Donisa Dreghici, MD, senior vice president and head, clinical development, Solid Biosciences.

“We are encouraged by the motor function, pulmonary function and patient reported outcome data which show that patients continue to experience durable benefit across all reported measures two years after SGT-001 dosing,” Dreghici said in a statement.² “This is important as the evidence suggests that these patients treated with SGT-001 show potentially sustained or improved performance at a time when expected natural history would suggest a decline.”

The updated, 2-year data for the 3 patients are in line with previous data reported from the 12- and 18-month time points and continue to show durable benefit. Differing from natural history, these patients exhibited improved motor function, with a mean 16-meter improvement (range, -12 to 39; mean difference from natural history, +100.6) in 6-Minute Walk Test from baseline and a –1.7 change (range, -3 to –1; mean difference from natural history, +4.3) in North Star Ambulatory Assessment from baseline.

READ MORE: SGT-001 Improves Pulmonary Function in Duchenne Muscular Dystrophy

These patients also showed improvements from baseline differing from natural history in pulmonary function with a mean 9.2% improvement in forced vital capacity (range, -1.4 to 29.0; mean difference from natural history, +19.2) and a 6.5% improvement in peak expiratory flow (range, -5.8 to 14.8; mean difference from natural history, +16.5).

“We are especially pleased that the data suggests sustained benefit of pulmonary function at the 2-year timepoint, which may lead to delayed ventilation and improved quality of life, as well as potentially an increased life expectancy,” Dreghici added.² 

Patient reported outcome measures as assessed in key functional domains of the Pediatric Outcomes Data Collection Instrument (PODCI) also were improved when compared with both baseline and natural history, with a mean 6.3-point improvement in PODCI global function (range, 0-13; mean difference from natural history, +16.4), a 0.7-point improvement in PODCI transfer/basic mobility (range, -4 to 6; mean difference from natural history, +20.6), and a 13.3-point improvement in PODCI sports/physical functioning (range, 12-15; mean difference from natural history, +19.5).

SGT-001 continues to be well-tolerated, with no new treatment-related adverse events in the 9 patients dosed so far, with follow-up for up to 4 years. The IGNITE-DMD trial will finish dosing patients in 2022 and will commence further discussions with the FDA at that time.

Solid also reported data from skeletal muscle biopsies from the 3 patients most recently treated with the high dose of SGT-001, collected 3 months after treatment. Immunofluorescence and western blot findings were within the range of the first 3 patients in the higher-dose cohort. All patients in this cohort have demonstrated microdystrophin expression and proper membrane localization. 

REFERENCES

1. Dreghici R, Redican S, Lawrence J, et al. Ignite DMD phase I/II study of SGT-001 microdystrophin gene therapy for DMD: 2-year outcomes update. Presented at MDA Clinical and Scientific Conference; March 13-16. Poster 46.
2. Solid Biosciences reports fourth quarter and full-year 2021 financial results and 2-year efficacy and safety data from the ongoing phase I/II IGNITE DMD clinical trial of SGT-001. News release. Solid Biosciences. March 14, 2022. https://www.solidbio.com/about/media/press-releases/solid-biosciences-reports-fourth-quarter-and-full-year-2021-financial-results-and-2-year-efficacy-and-safety-data-from-the-ongoing-phase-i-ii-ignite-dmd-clinical-trial-of-sgt-001