ASP2957

ASP2957 is an investigational gene therapy in development for the treatment of x-linked myotubular myopathy (XLMTM), a rare congenital disorder caused by mutations in the MTM1 gene that result in deficient production of myotubularin, a protein essential for muscle development and maintenance. ASP2957 is designed to deliver a functional copy of the MTM1 gene to patient cells to restore myotubularin expression and thereby improve muscle function and reduce disease symptoms. The therapy is administered as a single intravenous infusion, utilizing an adeno-associated virus vector (AAV) for gene delivery[1][4][7]. The drug is being tested in young children (age ≤3 years) in a first-in-human dose escalation and expansion study. The developer, Astellas Gene Therapies (formerly Audentes Therapeutics), received FDA IND clearance in July 2025 to conduct a Phase 1/2 trial in the United States[1][2][4].