Sanofi’s SAR446268 earns US fast track designation for the treatment of non-congenital myotonic dystrophy type 1 Designation earned for one-time AAV gene therapy SAR446268, designed to silence DMPK expressionMyotonic dystrophy type 1 (DM1) is a rare, genetic disorder that causes progressive muscle weakness and wasting, with no currently approved medicines Paris, September 23, 2025. The US Food and Drug Administration (FDA) has granted fast track designation to SAR446268, Sanofi's one-time AAV gene therapy f ...