Dyne Therapeutics Secures FDA Breakthrough Therapy Designation for DYNE-101 in Myotonic Dystrophy Type 1 (DM1)
Wednesday, June 18, 2025
Dyne Therapeutics has announced that the U.S. Food and Drug Administration (FDA) has granted Breakthrough Therapy Designation to DYNE-101, an investigational treatment for myotonic dystrophy type 1 (DM1).
DYNE-101 is a novel therapeutic under investigation in the global Phase 1/2 ACHIEVE trial. It is composed of an antisense oligonucleotide (ASO) linked to a fragment antibody targeting transferrin receptor 1 (TfR1), facilitating delivery to muscle and the central nervous system.
It aims to reduce toxic DMPK RNA and correct the abnormal splicing process seen in DM1.
DM1 is a rare, inherited condition affecting muscle and nervous system function. It is caused by a CTG trinucleotide repeat expansion in the DMPK gene, leading to the accumulation of toxic RNA in the cell nucleus. This disrupts normal protein splicing and results in a broad range of symptoms including muscle stiffness, weakness, fatigue, heart and respiratory issues, and cognitive difficulties.
There are currently no approved therapies that modify the course of the disease. DM1 is estimated to affect over 40,000 individuals in the U.S. and more than 74,000 in Europe.
The announcement follows a recent Type C meeting with the FDA and the availability of new long-term functional data. The company also shared its updated regulatory pathway, aiming for Accelerated Approval in the United States.
Dyne plans to use these results, along with data from other parts of the ACHIEVE trial, to support a potential Accelerated Approval submission by the end of 2026. A confirmatory Phase 3 trial is planned to begin in the first quarter of 2026.
The company is also exploring accelerated regulatory pathways in other countries.
The treatment continues to demonstrate a favourable safety profile, with no serious adverse events related to the drug reported in 56 participants.
As of 31 March 2025, Dyne reported cash and investments totalling $677.5 million and expects to maintain operations into the fourth quarter of 2026.
Breakthrough Therapy Designation is intended to speed up the development of medicines showing early evidence of significant improvement over existing therapies.
Benefits include increased guidance from senior FDA officials, frequent communications on trial design and regulatory issues, and eligibility for expedited reviews.
Source: dyne-tx.com
