Data Readout

Dyne's ACHIEVE trial for DM1 heads to a Q1 2027 readout after full enrollment

Enrollment at 116 is unchanged, but the primary completion date moved from 2026 to 2029, even as Dyne says the registrational readout stays on track for Q1 2027.

By AppliedXLJuly 13, 2026Trial NCT05481879

Executive Summary

Dyne Therapeutics is heading toward a first-quarter 2027 readout of its expansion cohort testing DYNE-101 in myotonic dystrophy type 1, a disease with no approved disease-modifying treatment.
Early data from a small dosing cohort showed descriptive improvement across myotonia, strength, and function measures with a favorable safety profile, but the sample size limits what it can prove.
The trial's primary completion date pushed out by three years even as the sponsor has repeated the same first-quarter 2027 readout guidance across multiple disclosures, pointing to a program whose interim data timeline has stayed stable while its full completion horizon extended.
DYNE-101 sits alongside a small number of RNA-targeted and small-molecule programs in DM1, none of which share its exact target and mechanism, leaving the readout as the nearest test of whether directly suppressing the toxic RNA translates into functional benefit.

The catalyst

Dyne Therapeutics plans to report data from the registrational expansion cohort of the ACHIEVE trial (NCT05481879) in the first quarter of 2027 to support a potential Biologics License Application for z-basivarsen, also known as DYNE-101. The company said in its first-quarter 2026 update that it had reached its target of 60 participants in the expansion cohort and expected to exceed that number as enrollment completed in the second quarter of 2026. John Cox, Dyne's president and chief executive officer, said the company is "driven by our goal to deliver functional improvement for individuals living with DM1" as it looks toward "the important expected readout in the first quarter of 2027". NCT05481879+1

Probability of Success

Endpoint Met99%

Completes61%

Clinical Significance87%

Regulatory75%

What the trial measures

ACHIEVE is a Phase 1/2 trial with 116 participants across the United States, United Kingdom, France, Germany, Italy, Australia, the Netherlands, and New Zealand. Its primary endpoints are change from baseline in myotonia, measured by video hand opening time, in the dose-expansion cohorts, and the incidence of treatment-emergent adverse events in the multiple-ascending-dose cohorts. The trial is not registered as registrational at the study level, even though Dyne has described the expansion cohort itself as the basis for a planned BLA filing. NCT05481879+1

Timeline signal

The trial's primary completion date moved from July 2026 to July 2029, a 36-month shift recorded in March 2025. Enrollment grew from 64 to 116 participants across three separate registry updates between May 2023 and August 2025, and has held at 116 since. Twenty-six disclosures since May 2026 have repeated the same first-quarter 2027 readout window, indicating the interim data timeline guidance has not shifted even as the trial's full completion date extended years further out. NCT05481879+1

The early data

One-year data from a 6.8 mg/kg cohort dosed every eight weeks, in 6 participants, showed descriptive improvement from baseline across myotonia, walking and stair-climbing measures, hand grip strength, and patient-reported health index scores, Dyne disclosed at the World Muscle Society meeting in October 2025. Safety was described as favorable across 56 participants, with no related serious treatment-emergent adverse events reported. The sample size in the reported cohort is too small to support a rate calculation, and the data preceded any placebo-controlled comparison. Dyne

Where it sits competitively

DYNE-101 is the only Phase 1 asset targeting DMPK RNA in DM1 on record, and Dyne's own Phase 3 HARMONIA trial for the same drug, initiated in March 2026, is its nearest same-drug precedent. Other DM1 programs in the field, including Avidity Biosciences' Delpacibart Etedesiran, which also targets DMPK RNA but through a different oligonucleotide modality, and Sanofi's SAR446268 gene therapy, work through different mechanisms or delivery approaches, leaving no direct mechanism-matched comparator with posted results to benchmark against. The indication itself carries no approved disease-modifying treatment, which sets a bar of durable, dose-confirmed functional improvement, rather than incremental descriptive change, for any readout in this class to be informative. Dyne

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