Sanofi’s SAR446268 Therapy Receives US Fast Track Designation for Non-Congenital Myotonic Dystrophy Type 1
Tuesday, September 23, 2025
The U.S. Food and Drug Administration (FDA) has granted Fast Track designation to SAR446268, Sanofi’s AAV gene therapy for juvenile and adult non-congenital myotonic dystrophy type 1 (DM1). The Fast Track process is designed to accelerate the development and review of treatments for serious conditions with unmet medical needs, helping patients access important new therapies more quickly.
SAR446268 employs a vector-based RNA interference (RNAi) approach to silence DMPK gene expression with a single administration. By reducing DMPK transcripts, the therapy aims to remove abnormal RNA foci responsible for splicing defects in muscle tissue, restoring normal splicing and improving muscle function. This method has the potential to address key symptoms of DM1, including progressive muscle weakness, myotonia, and effects on the heart, lungs, and endocrine systems. SAR446268 is currently the only investigational therapy in clinical development for DM1, a condition for which no approved treatments exist.
The therapy is being evaluated in a first-in-human Phase 1–2 study (Clinical Study Identifier: NCT06844214) to assess safety, tolerability, and efficacy, with the first patient expected to be enrolled by the end of 2025. Sanofi has already secured orphan drug designation for SAR446268 in the US (July 2024) and the EU (October 2024).
Myotonic dystrophy type 1, also called Steinert disease, is a rare, progressive inherited disorder affecting about 1 in 2,300 people worldwide. It results from mutations in the DMPK gene and is characterised by muscle weakness, myotonia, and multi-system effects, impacting patients’ daily activities, independence, and, in severe cases, vital functions. The condition can present at any age, with symptoms ranging from mild adult forms to severe congenital cases.
Source: globenewswire.com
