Dyne Therapeutics announced 12-month data on September 29, 2026, showing functional improvements across multiple metrics for its myotonic dystrophy type 1 (DM1) drug candidate z-basivarsen (DYNE-101) in an ACHIEVE clinical trial.
ACHIEVE Trial Pooled Dose Results at 12 Months
Data presented at the 31st Annual International Congress of the World Muscle Society and the 2026 American Association of Neuromuscular & Electrodiagnostic Medicine annual meeting track participants receiving z-basivarsen over an extended period. The pooled dose cohort included participants from the 3.4 mg/kg every-four-weeks, 5.4 mg/kg every-eight-weeks, and 6.8 mg/kg every-eight-weeks dosing schedules. Dyne Therapeutics noted that only eight of the 26 participants received the full registration dose of 6.8 mg/kg for the entire 12-month duration, reflecting the exploratory nature of the pooled analysis.
Video hand opening time (vHOT), a core measure of myotonia, started at a baseline average of 8.2 seconds for the pooled cohort. At six months, vHOT dropped by 3.2 seconds. In contrast, 14 placebo participants in the ACHIEVE trial experienced a 0.4-second increase over the same timeframe, yielding a relative improvement of 3.6 seconds. For functional endurance, the five-times sit-to-stand test improved by 1.2 seconds at 12 months, and the 10-meter walk-run test improved by 0.3 seconds compared to baseline.
Comparison with Natural History Controls
To contextualize the open-label findings, Dyne Therapeutics compared the trial data against a propensity-score-matched natural history cohort of 41 to 46 individuals from the ongoing END-DM1 study. Quantitative muscle testing and grip strength scores both showed a 4.8% improvement relative to predicted values at 12 months, with widening margins against the matched natural history group.
Patient-reported outcomes measured by the Myotonic Dystrophy Health Index total score showed a 25.2% improvement from baseline. Participants reported sustained relief across six subdomains covering central nervous system symptoms, including daytime sleepiness, fatigue, and pain. Chief Medical Officer Doug Kerr stated that the data reinforce confidence in the FORCE platform, which couples an antisense oligonucleotide with a Fab fragment targeting transferrin receptor 1 to deliver payloads into muscle and central nervous system tissue.
Safety Profile and Regulatory Timeline
Z-basivarsen maintained a favorable safety profile through the data cutoff date of April 20, 2026, with no related serious treatment-emergent adverse events reported. The therapy holds orphan drug, fast track, and breakthrough therapy designations from the U.S. Food and Administration, alongside orphan drug status from the European Medicines Agency and Japan’s Ministry of Health, Labour and Welfare.
Dyne Therapeutics plans to release topline results from the registration-directed expansion cohort of the ACHIEVE trial in the first quarter of 2027. That cohort’s primary endpoint centers on the change in vHOT at six months, which will serve as the backbone for a biologics license application seeking accelerated approval from the FDA in the third quarter of 2027. Meanwhile, the global Phase 3 HARMONIA trial continues to recruit participants across more than 35 active sites to support broader regulatory submissions.
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