MUSCLE FUNCTION & HOMEOSTASIS / MOLECULAR THERAPEUTIC APPROACHES: P.62 ASPIRO Gene therapy trial in X-linked myotubular myopathy (XLMTM): Update on preliminary safety and efficacy findings up to 72 weeks post-treatment

Abstract

XLMTM, a rare monogenic disease caused by mutations in the MTM1 gene, is characterized by profound muscle weakness, respiratory failure, and early death. ASPIRO is an ongoing, open-label, randomized study (NCT03199469) evaluating safety/efficacy of AT132, an investigational gene therapy for delivery of functional MTM1 gene copies. XLMTM patients, ≤7 years old, were randomized to treatment or delayed-treatment control and enrolled into ascending dose cohorts to receive a single AT132 infusion. Safety/efficacy data are available for 12 patients with 4–72 weeks’ follow-up: 6, Cohort 1 (1 × 1014 vg/kg); 4, Cohort 2 (3 × 1014 vg/kg); 2, controls.