secwatch.observer — SEC 8-K summary
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Issuer:     Dyne Therapeutics, Inc. (DYN)
CIK:        0001818794
Form:       8-K
Filed at:   2026-09-29T20:10:18+00:00
Accession:  0001818794-26-000009
Event type: other_material
Sentiment:  positive
Materiality: 0.60
Item codes: 7.01, 8.01, 9.01
LLM model:  deepseek-v4.1-flash:cloud@v2

Dyne ACHIEVE 1-year data: vHOT fell 3.2 sec vs placebo's 0.4 sec rise; REC topline due Q1 2027
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- Pooled dose group (N=25-26) drawn from 3.4 mg/kg Q4W, 5.4 mg/kg Q8W and 6.8 mg/kg Q8W MAD cohorts; mean baseline vHOT 8.2 sec fell 3.2 sec at 6 months vs a 0.4 sec rise on placebo (N=14).
- At 12 months the pooled group improved 5xSTS by 1.2 sec and 10MWR by 0.3 sec; QMT total and hand grip each rose 4.8% predicted, diverging from the matched natural history cohort on 10MWR and QMT.
- MDHI patient-reported total score improved 25.2% from baseline at 12 months vs an unmatched END-DM1 cohort (N=410); safety data as of April 20, 2026 showed no related serious TEAEs.
- ACHIEVE REC (71 participants) mean baseline vHOT is 8.3 sec and remains blinded; topline expected Q1 2027 to support a BLA for U.S. Accelerated Approval in Q3 2027.
- Phase 3 HARMONIA, with 12-month change in 5xSTS as the primary confirmatory endpoint, is recruiting at over 35 active global sites.

Source:
  EDGAR index:    https://www.sec.gov/Archives/edgar/data/1818794/000181879426000009/0001818794-26-000009-index.htm
  Primary doc:    https://www.sec.gov/Archives/edgar/data/1818794/000181879426000009/dyn-20260929.htm
  HTML page:      https://secwatch.observer/filing/0001818794-26-000009

License: Source filings: public domain (SEC EDGAR). Summaries (headline + bullets): CC-BY-4.0; attribute https://secwatch.observer