Dyne is advancing z-basivarsen from a positive Phase 1/2 DM1 signal toward registrational testing: the company completed enrollment in the ACHIEVE registrational expansion cohort and has begun the confirmatory HARMONIA Phase 3 program.
The one-year signal remains directionally strong across meaningful measures. In the pooled ACHIEVE group, quantitative muscle strength improved 9.9% from baseline at 12 months, the 5-times-sit-to-stand time improved 11.5%, and patient-reported disease burden on MDHI improved 25.2% (12-month efficacy slides). The consistency across strength, mobility and patient-reported outcomes makes this more useful than a single biomarker or myotonia readout.
The comparison against natural history strengthens the case that this may be treatment effect, not just noise. At one year, the pooled group improved while matched END-DM1 participants generally worsened on total strength, hand grip and walking time; the filing also says MDHI improvement exceeded a minimal clinically important difference. 〔0〕 〔1〕
| Measure | 12-month change | Comparison / context |
|---|---|---|
| QMT total strength | +9.9% from baseline | Pooled dose group, N=25 |
| Hand-grip strength | +11.2% from baseline | Pooled dose group, N=25 |
| 5-times sit-to-stand | -11.5% time | Pooled dose group, N=26 |
| 10-meter walk/run | -6.4% time | Pooled dose group, N=26 |
| MDHI total score | -25.2% | Pooled dose group, N=25 |
| Treatment-emergent adverse events | 100% had at least one | Overall safety population, N=56 |
The main limitation is that the headline efficacy analysis is not a clean registrational-dose result. The pooled group combines 3.4, 5.4 and 6.8 mg/kg cohorts, and only 8 of 26 participants received the 6.8 mg/kg registrational dose for the entire 12 months. 〔2〕 That makes the result supportive, but it cannot establish how the selected dose will perform in the larger registrational cohort.
Safety remains workable, but not uneventful. No serious treatment-related adverse events or deaths were reported, although infusion reactions were common and liver-enzyme elevations occurred in a minority of participants. 〔3〕 The safety database is also still small for a therapy intended for broader use, despite roughly 1,300 doses administered and more than 143 patient-years of follow-up. 〔4〕
Bottom line: This update advances Dyne’s DM1 story from early biological activity toward a credible functional-benefit profile, with natural-history comparisons adding support. It is encouraging rather than definitive because the strongest one-year data come from a small, mixed-dose pooled group; the larger registrational readout remains the real test, currently planned for the first quarter of 2027.
Read the original 8-K on SEC EDGAR ↗