Dyne Therapeutics, Inc. · NASDAQ:DYN

Dyne Therapeutics — World Muscle Society 31st Annual Congress 2026

22 slides from Dyne Therapeutics's conference presentation, Sep 29, 2026

  1. Slide 1: Long-Term Functional Improvement With Zeleciment Basivarsen in the Phase 1/2 ACHIEVE Trial

    ‘World Muscle Society Long-Term Functional Improvement With Zeleciment Basivarsen in the Phase 1/2 ACHIEVE Trial Karlien Mul, MD, PhD‘, Guillaume Bassez2, Jordi Diaz-Manera?, James Lilleker*, Marika Pane®, Richard Roxburgh®, Benedikt Schoser’, Christopher Turner®, Allison Kreuzer®, Alexandra Lovett®

  2. Slide 2: Disclosure

    World Muscle Society Disclosure ¢ Dr. Mul has served as a paid consultant for Dyne Therapeutics, Avidity Biosciences, and Sarepta Therapeutics. She received research funding from Vertex Pharmaceuticals and PepGen Inc. ¢ Zeleciment basivarsen (z-basivarsen, also known as DYNE-101) is investigational

  3. Slide 3: Z-Basivarsen Addresses the Central Pathobiology of DM1 to Enable Broad Functional Improvement

    Z-Basivarsen Addresses the Central Pathobiology of DM1 to Enable Broad Functional Improvement1 3 Muscle Strength: Quantitative Muscle Testing Timed-Function Tests: 5 Times Sit to Stand; 10-Meter Walk / Run Patient-Reported Outcomes: Myotonic Dystrophy Health Index (MDHI) Robust and widespread delive

  4. Slide 4: ACHIEVE Multiple Ascending Dose Study

    ACHIEVE Multiple Ascending Dose Study 5.4 mg/kg N=8 (3:1) Q8W, Placebo 6.8 mg/kg N=8 (3:1) Q8W, Placebo 3.4 mg/kg N=8 (3:1) Q8W, Placebo 1.8 mg/kg N=16 (3:3:2) Q4W, Recovery, Placebo Open-label extension (OLE) Long-term extension (LTE) Primary endpoints Safety and tolerability Additional endpoints M

  5. Slide 5: ACHIEVE MAD Study: Efficacy Analysis of Pooled Dose Group

    ACHIEVE MAD Study: Efficacy Analysis of Pooled Dose Group 5 1.8 mg/kg (N=16, Q4W) Included in Pooled Dose Group Lower dose cohorts not included in the efficacy analysis 5.4 mg/kg (N=8, Q8W) 6.8 mg/kg (N=8, Q8W) Previous long-term analysis included N=6 assigned to 6.8 mg/kg (registrational dose) at b

  6. Slide 6: Analysis of ACHIEVE versus END-DM1 natural history

    Analysis of ACHIEVE versus END-DM1 natural history Data from 6.8 mg/kg cohort and analysis of Pooled Dose Group: vHOT Clinical outcome measures of muscle strength and function Patient-reported outcomes Data from ACHIEVE MAD as of April 20, 2026 Z-Basivarsen ACHIEVE MAD Clinical Update 6 Safety Effic

  7. Slide 7: ACHIEVE MAD Baseline Characteristics

    ACHIEVE MAD Baseline Characteristics 7 Mean (SD) Placebo (N=14) 6.8 mg/kg Q8W (N=6) Pooled dose group (N=26) Age (years) 32.6 (9.6) 37.2 (9.7) 35.6 (8.0) BMI (kg/m2) 24.4 (4.7) 23.4 (5.6) 22.7 (3.9) CASI-22 0.68 (0.20) 0.74 (0.25) 0.73 (0.19) CTG repeats 597 (246) 542 (191) 527 (243) vHOT (middle fi

  8. Slide 8: Favorable Safety Profile With No Serious Related TEAEs

    Favorable Safety Profile With No Serious Related TEAEs1 Summary of treatment-emergent adverse events (TEAEs)1 TEAE category Participants with ≥1 TEAE, n (%) 1.8 mg/kg Q4W+Rec. N=16 3.4 mg/kg Q4W+Rec. N=16 3.4 mg/kg Q8W N=8 5.4 mg/kg Q8W N=8 6.8 mg/kg Q8W N=8 Overall (N=56) Any TEAE 16 (100) 16 (100)

  9. Slide 9: Pooled Efficacy Data Continue to Support vHOT as an Early Indicator of Functional Improvement

    -10 -5 0 10 9 Placebo Month 6 (N=141) Pooled Dose Group Month 12 (N=25-26) 5xSTS (sec) 0.48 5 −1.18 QMT Total (%p) -2.0 4.8 Improvement Mean Change From Baseline (SEM) Pooled Dose Group vHOT Middle Finger: Pooled Dose Group MDHI1 (total score) 1.9 10MWR (sec) -0.26 0.14 Hand Grip (%p) -2.5 Pooled Ef

  10. Slide 10: Improvement in Strength Is Sustained at 12 Months, as Measured by QMT

    QMT Total (%p) Change From Baseline (Mean ± SEM) 6 months 12 months 0 5 10 15 -5 +10.3 +20.1% Δ from BL -2.0 -3.9% Δ from BL BL Patients, N Placebo 6.8 mg/kg 14 6 14 6 - 6 Baseline Mean (SEM) 51.5 (3.8) 51.3 (4.2) QMT Total (%p) Change From Baseline (Mean ± SEM) BL 6 months 12 months 0 5 10 15 -5 +4

  11. Slide 11: Improvement in Motor Function Is Sustained at 12 Months, as Measured by 5xSTS

    -3 -2 -1 0 1 2 5×STS (sec) Change From Baseline (Mean ± SEM) 6 months 12 months -1.45 -14.5% Δ from BL +0.48 +5.2% Δ from BL BL Patients, N Placebo 6.8 mg/kg 14 6 14 6 - 6 Baseline Mean (SEM) 9.2 (0.5) 10.0 (1.4) -3 -2 -1 0 1 2 5×STS (sec) Change From Baseline (Mean ± SEM) BL 6 months 12 months -1.1

  12. Slide 12: Improvement in Patient-Reported Disease Burden Is Sustained at 12 Months, MDHI

    -15 -10 -5 0 5 MDHI Total Score Change From Baseline (Mean ± SEM) 6 months 12 months +1.9 +10.0% Δ from BL BL Pateints, N -12.3 -46.4% Δ from BL Placebo 6.8 mg/kg 13 6 13 6 - 6 Baseline Mean (SEM) 18.7 (3.8) 26.5 (5.6) -15 -10 -5 0 5 MDHI Total Score Change From Baseline (Mean ± SEM) BL 6 months 12

  13. Slide 13: END-DM1 Assesses Natural DM1 Progression

    END-DM11 Assesses Natural DM1 Progression Dyne Therapeutics is one of multiple companies funding the END-DM1 study, along with the US Food and Drug Administration (FDA) and the Myotonic Dystrophy Foundation (MDF). The Myotonic Dystrophy Clinical Research Network (DMCRN), consisting of END-DM1–partic

  14. Slide 14: ACHIEVE Pooled Dose Group Improves From Baseline and Diverges From Natural History

    ACHIEVE Pooled Dose (N=26) END-DM1 (N=46) 0.57 sec -4 -2 0 2 4 6 8 4.3 %p ACHIEVE Pooled Dose (N=25) END-DM1 (N=46) -4 -2 0 2 4 6 8 1 Year Mean Change from Baseline (SEM) 4.8 %p ACHIEVE Pooled Dose (N=25) END-DM1 (N=41) ACHIEVE Pooled Dose Group Improves From Baseline and Diverges From Natural Histo

  15. Slide 15: Improvement in MDHI in ACHIEVE Pooled Dose Group Exceeded MCID

    4 2 0 -2 -4 -6 -8 -10 -12 -12 -10 -8 -6 -4 -2 0 2 4 -12 -10 -8 -6 -4 -2 0 -12 -10 -8 -6 -4 -2 0 -12 -10 -8 -6 -4 -2 0 4 2 4 2 4 2 -12 -10 -8 -6 -4 -2 0 2 4 6 4 2 0 -2 -4 -6 -8 -10 -25.2% Δ from BL ACHIEVE Pooled Dose N=25 24.6 (4.0) MDHI Total Score Change From Baseline, Mean (SEM) END-DM1 N=410 25.

  16. Slide 16: Summary: Z-Basivarsen ACHIEVE MAD Clinical Update

    Z-basivarsen–treated participants showed divergence from natural history across functional and strength outcomes Functional improvements in MDHI Total Score exceeded MCID and diverged from natural history control 6.8 mg/kg cohort demonstrated durable functional improvement in myotonia, motor functio

  17. Slide 17: Acknowledgments

    Acknowledgments ¢ ACHIEVE participants, families, investigators, and site staff ¢ Myotonic Dystrophy Clinical Research Network (DMCRN) and END-DM1 participants, families, and research personnel ¢ Members of the DM1 community who have provided feedback, insights, and questions To view the presentatio

  18. Slide 18: Appendix: Long-Term Functional Improvement With Zeleciment Basivarsen

    World Muscle Society Long-Term Functional Improvement With Zeleciment Basivarsen in the Phase 1/2 ACHIEVE Trial Karlien Mul, MD, PhD‘, Guillaume Bassez2, Jordi Diaz-Manera?, James Lilleker*, Marika Pane®, Richard Roxburgh®, Benedikt Schoser’, Christopher Turner®, Allison Kreuzer®, Alexandra Lovett®,

  19. Slide 19: Improvement in Strength Is Sustained at 12 Months, Including Hand Grip

    -10 -5 0 5 10 15 Hand Grip Strength (%p) Change From Baseline (Mean ± SEM) BL 6 months 12 months -2.5 -5.5% Δ from BL +6.9 +14.1% Δ from BL Placebo 6.8 mg/kg Patients, N 14 6 14 6 - 6 Baseline Mean (SEM) 44.8 (4.5) 49.0 (5.3) -10 -5 0 5 10 15 Hand Grip Strength (%p) Change From Baseline (Mean ± SEM)

  20. Slide 20: Improvement in Motor Function Is Sustained at 12 Months, as Measured by 10MWR

    -0.75 -0.50 -0.25 0.00 0.25 0.50 0.75 1.00 10-Meter Walk/Run Test (sec) Change From Baseline (Mean ± SEM) +0.14 +4.3% Δ from BL BL 6 months 12 months Baseline BL 6 months 12 months Baseline Mean (SEM) Patients, N Mean (SEM) 4.0 (0.3) Patients, N 26 26 26 Placebo 6.8 mg/kg 3.3 (0.1) 3.9 (0.6) 14 6 14

  21. Slide 21: MDHI Pain, Fatigue and Communication Subscales

    -30 -25 -20 -10 -15 -5 0 5 MDHI Pain Change From Baseline (Mean ± SEM) BL 6 months 12 months -15.1 -60.2% Δ from BL +1.79 +8.1% Δ from BL Patients, N Placebo 13 6 13 6 - 6 BL: Mean (SEM) Placebo: 22.15 (7.0) 6.8 mg/kg: 25.1 (11.1) -30 -25 -20 -15 -10 -5 0 5 MDHI Fatigue Change From Baseline (Mean ±

  22. Slide 22: MDHI Cognitive Impairment, Sleep and Emotional Issues

    -20 -10 0 10 20 MDHI Cognitive Impairment Change From Baseline (Mean ± SEM) BL 6 months 12 months -8.0 -34.2% Δ from BL +7.5 +117% Δ from BL Patients, N Placebo 6.8 mg/kg 13 6 13 6 - 6 BL: Mean (SEM) Placebo: 6.4 (2.4) 6.8 mg/kg: 23.3 (6.7) -50 -40 -30 -20 -10 0 10 MDHI Sleep Change From Baseline (M

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