Dyne Therapeutics' DYNE-101 Shows Promising Results in Myotonic Dystrophy Type 1; Registrational Expansion Cohort Planned for Potential U.S. Accelerated Approval in H1 2026

Dyne Therapeutics, Inc. (Nasdaq: DYN), a clinical-stage muscle disease company, has reported new clinical data from its ongoing Phase 1/2 ACHIEVE trial of DYNE-101 in patients with myotonic dystrophy type 1 (DM1). The data demonstrate a compelling impact on multiple measures of the disease, including key biomarkers and functional endpoints. Based on these encouraging results, Dyne plans to initiate a registrational expansion cohort to support a potential submission for U.S. Accelerated Approval for DYNE-101 in DM1 in H1 2026.



Myotonic dystrophy type 1 (DM1) is a rare, progressive genetic disease that affects more than 40,000 people in the United States and over 74,000 people in Europe. DM1 is a monogenic, autosomal dominant disease caused by an abnormal expansion in a region of the DMPK gene. DYNE-101, an investigational therapeutic being evaluated in the Phase 1/2 global ACHIEVE clinical trial, is designed to address the genetic basis of DM1 by reducing the levels of mutant DMPK RNA in the nucleus, releasing splicing proteins, allowing normal mRNA processing and translation of normal proteins, and potentially stopping or reversing disease progression.

In the ACHIEVE trial, DYNE-101 demonstrated consistent, dose-dependent splicing correction, muscle delivery, and DMPK knockdown. All evaluable patients in the 3.4 mg/kg Q4W cohort treated with DYNE-101 showed consistent splicing correction with a 19% mean improvement across a 22-gene panel at 3 months. Improvement in myotonia (vHOT) was observed in the lowest dose ACHIEVE cohort at 6 months, with a mean 3.1 second benefit in myotonia at 3 months that increased to 4.4 seconds at 12 months. Additionally, the 5.4 mg/kg Q8W cohort had a mean 4.5 second improvement in myotonia at 3 months. Treatment with DYNE-101 also led to an improvement in muscle strength, function, and patient-reported outcomes.



Dyne Therapeutics' FORCE™ platform, which enables targeted muscle tissue delivery and promotes exon skipping in the nucleus, has shown promise in addressing rare muscle diseases. The company is building a global DMD franchise and has preclinical programs targeting other exons, including 53, 45, and 44. Dyne is also exploring diseases involving the CNS and expanding its pipeline to address the significant unmet needs of people living with neuromuscular diseases.

The potential timeline for regulatory submission and approval of DYNE-101 for DM1 is as follows:

* Dyne plans to initiate a global registrational expansion cohort of the ACHIEVE trial with a registrational dose of 6.8 mg/kg Q8W following study data showing splicing correction and robust and sustained functional improvements.
* The potential submission for U.S. Accelerated Approval is targeted for H1 2026.
* Dyne continues to pursue expedited approval pathways globally for DYNE-101 utilizing splicing as a surrogate endpoint.

In conclusion, Dyne Therapeutics' DYNE-101 has shown promising results in the treatment of myotonic dystrophy type 1, with compelling impact on multiple measures of the disease. The company plans to initiate a registrational expansion cohort to support a potential submission for U.S. Accelerated Approval in H1 2026. As Dyne continues to advance its clinical programs and expand its pipeline, it remains on track to transform the treatment paradigm for patients living with DM1 and other neuromuscular diseases.