Study of SRP-1003 in Participants With Type 1 Myotonic Dystrophy

August 7, 2026 updated by: Sarepta Therapeutics, Inc.

A Phase 1/2a Dose-Escalating Study to Evaluate the Safety, Tolerability, Pharmacokinetics, and Pharmacodynamics of ARO-DM1 (SRP-1003) in Subjects With Type 1 Myotonic Dystrophy Who Are ≥18 to ≤ 65 Years

This is a phase 1/2a double-blinded, placebo-controlled, dose-escalating study to evaluate the safety, tolerability, pharmacokinetics (PK) and pharmacodynamics of single and multiple ascending doses of SRP-1003 compared to placebo in male and female participants with type 1 myotonic dystrophy (DM1). Participants who have provided written informed consent and met all protocol eligibility requirements will be randomized to receive single (Part 1) or multiple (Part 2) doses of SRP-1003 or placebo.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Estimated)

78

Phase

  • Phase 2
  • Phase 1

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

  • Name: Sarepta Therapeutics Inc. For Clinical Trial Information, Select Option 4
  • Phone Number: 1-888-SAREPTA (1-888-727-3782)
  • Email: SareptAlly@sarepta.com

Study Locations

  • Australia
      • Herston, Australia
        • Recruiting
        • Nucleus Network Brisbane Clinic
      • South Brisbane, Australia
        • Recruiting
        • Mater Hospital Brisbane
    • New South Wales
      • Liverpool, New South Wales, Australia, 2170
        • Recruiting
        • Liverpool Hospital
    • Queensland
      • Birtinya, Queensland, Australia, 4575
        • Recruiting
        • Sunshine Coast University Hospital
      • Herston, Queensland, Australia
        • Recruiting
        • Royal Brisbane and Women's Hospital
    • Victoria
      • Melbourne, Victoria, Australia, 3004
        • Recruiting
        • Alfred Health
  • Belgium
      • Ghent, Belgium
        • Recruiting
        • Universitair Ziekenhuis Gent
      • Leuven, Belgium
        • Recruiting
        • UZ Leuven
  • Canada
      • Calgary, Canada
        • Recruiting
        • University of Calgary
      • Edmonton, Canada
        • Recruiting
        • University of Alberta
      • Montreal, Canada
        • Recruiting
        • McGill University
  • France
      • Angers, France
        • Recruiting
        • University Hospital of Angers
      • Bordeaux, France
        • Recruiting
        • Centre hospitalier universitaire de Bordeaux
      • Lille, France
        • Recruiting
        • Centre Hospitalier Universitaire de Lille
      • Nice, France
        • Recruiting
        • CHU de Nice - Hôpital Pasteur 2
      • Paris, France
        • Recruiting
        • Assistance Publique Hopitaux de Paris
  • Germany
      • Munich, Germany
        • Recruiting
        • Klinikum der Universität München AÖR
      • Ulm, Germany
        • Recruiting
        • Deutsches Zentrum für Neurodegenerative Erkrankungen e.V.
  • Italy
      • Gussago, Italy
        • Recruiting
        • Fondazione Serena Onlus - Centro Clinico NeMO Brescia
      • Milan, Italy
        • Recruiting
        • Centro Clinico Nemo (Milan)
      • Pisa, Italy
        • Recruiting
        • Azienda Ospedaliera Universitaria Pisana (AOUP)
      • Roma, Italy
        • Recruiting
        • Fondazione Policlinico Universitario Agostino Gemelli IRCCS
  • New Zealand
      • Christchurch, New Zealand, 8011
        • Recruiting
        • New Zealand Clinical Research Christchurch
  • Spain
      • Almería, Spain
        • Recruiting
        • Hospital Universitario Torrecárdenas
      • Barcelona, Spain
        • Recruiting
        • Hospital Universitari Vall d Hebron
      • Madrid, Spain
        • Recruiting
        • Hospital Universitario Infanta Sofía
  • Taiwan
      • Taichung, Taiwan, 40447
        • Recruiting
        • China Medical University Hospital
      • Taipei, Taiwan
        • Recruiting
        • Taipei Veterans General Hospital
      • Taipei, Taiwan
        • Recruiting
        • National Taiwan University Hospital
  • Thailand
      • Bangkok, Thailand, 10700
        • Recruiting
        • Siriraj Hospital
      • Lampang, Thailand, 52000
        • Recruiting
        • Lampang Hospital
    • Changwat Songkhla
      • Hat Yai, Changwat Songkhla, Thailand, 90110
        • Recruiting
        • Songklanagarind Hospital
  • United Kingdom
      • London, United Kingdom
        • Recruiting
        • The National Hospital for Neurology and Neurosurgery, NHS Foundation Trust
      • Nottingham, United Kingdom
        • Recruiting
        • Nottingham University Hospitals NHS Trust
      • Southampton, United Kingdom
        • Recruiting
        • Southampton General Hospital, NHS Foundation Trust

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Key Inclusion Criteria:

  • Genetically confirmed diagnosis of DM1
  • Clinician-assessed signs of DM1 including clinically apparent myotonia
  • Onset of DM1 symptoms occurred after the age of 12 years
  • Walk for at least 10 meters independently at screening
  • Participants of childbearing potential must agree to use highly effective contraception in addition to a condom during the study and for at least 90 days following the end of study or last dose of study drug, whichever is later. Participants must not donate sperm or eggs during the study and for at least 90 days following the end of study or last dose of study drug whichever is later.

Key Exclusion Criteria:

  • Inadequately controlled diabetes
  • Confirmed diagnosis of congenital DM1
  • Uncontrolled hypertension
  • History of tibialis anterior (TA) biopsy within 3 months of Day 1 or planning to undergo TA biopsies during the study period
  • Clinically significant cardiac, liver or renal disease
  • Human immunodeficiency virus infection (seropositive) at screening
  • Seropositive for hepatitis B or hepatitis C at screening
  • Untreated or poorly controlled epilepsy
  • Treatment with anti-myotonia medication within a period of 5 half-lives of the medication prior to screening.
  • Abnormal coagulation parameters at screening including platelet count, international normalized ratio, prothrombin time, and activated partial thromboplastin time

Note: Additional inclusion/exclusion criteria may apply per protocol

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Quadruple

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Placebo Comparator: Placebo by IV Infusion
Single or multiple doses of placebo by IV infusion
Drug: Placebo IV Infusion
0.9% sodium chloride (NaCl) calculated volume to match active treatment by IV infusion
Experimental: SRP-1003 IV Infusion
Single or multiple doses of SRP-1003 by intravenous (IV) infusion
Drug: SRP-1003 IV Infusion
SRP-1003 by IV infusion
Other Names:
  • ARO-DM1 IV Infusion
Experimental: SRP-1003 SC Injection
Single or multiple doses of SRP-1003 by subcutaneous (SC) injection
Drug: SRP-1003 SC Injection
SRP-1003 by SC injection(s)
Other Names:
  • ARO-DM1 SC Injection
Placebo Comparator: Placebo by SC Injection
Single or multiple doses of placebo by SC injection
Drug: Placebo SC Injection
0.9% NaCl calculated volume to match active treatment by SC injection(s)

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Time Frame
Number of Participants with Treatment-emergent Adverse Events Over Time Through End of Study (EOS)
Time Frame: Single-dose phase (Part 1): Up to Day 90 (EOS); multiple-dose phase (Part 2): Up to Day 180 (EOS)
Single-dose phase (Part 1): Up to Day 90 (EOS); multiple-dose phase (Part 2): Up to Day 180 (EOS)

Secondary Outcome Measures

Outcome Measure
Time Frame
Change from Baseline Over Time for the Timed Up and Go Test (TUG) Assessment
Time Frame: (Part 2): Baseline through EOS (up to 180 days)
(Part 2): Baseline through EOS (up to 180 days)
Change from Baseline Over Time for the 10-Meter Walk/Run Test (10MWT) Assessment
Time Frame: (Part 2): Baseline through EOS (up to 180 days)
(Part 2): Baseline through EOS (up to 180 days)
Change from Baseline Over Time for the Hand-held Quantitative Dynamometry Assessment
Time Frame: (Part 2): Baseline through EOS (up to 180 days)
(Part 2): Baseline through EOS (up to 180 days)
Change from Baseline Over Time for the Video Hand Opening Time (vHOT) Assessment
Time Frame: (Part 2): Baseline through EOS (up to 180 days)
(Part 2): Baseline through EOS (up to 180 days)
Change from Baseline Over Time for the Myotonic Dystrophy Type 1 Activity and Participation Scale (DM1-Activ-C) Assessment
Time Frame: (Part 2): Baseline through EOS (up to 180 days)
(Part 2): Baseline through EOS (up to 180 days)
Change from Baseline Over Time for the Myotonic Dystrophy Health Index (MDHI) Assessment
Time Frame: (Part 2): Baseline through EOS (up to 180 days)
(Part 2): Baseline through EOS (up to 180 days)
Change from Baseline at Day 120 for Video Hand Opening Time (vHOT)
Time Frame: (Part 2): Baseline, Day 120
(Part 2): Baseline, Day 120
PK of SRP-1003: Maximum Observed Plasma Concentration (Cmax)
Time Frame: Single-dose phase (Part 1): Up 24 hours post-dose; multiple-dose phase (Part 2): Through 24 hours post first and second dose
Single-dose phase (Part 1): Up 24 hours post-dose; multiple-dose phase (Part 2): Through 24 hours post first and second dose
PK of SRP-1003: Area Under the Plasma Concentration Versus Time Curve from Zero to 24 Hours (AUC0-24)
Time Frame: Single-dose phase (Part 1): Up 24 hours post-dose; multiple-dose phase (Part 2): Through 24 hours post first and second dose
Single-dose phase (Part 1): Up 24 hours post-dose; multiple-dose phase (Part 2): Through 24 hours post first and second dose
PK of SRP-1003: Area Under the Plasma Concentration Versus Time Curve from Zero to the Last Quantifiable Plasma Concentration (AUClast)
Time Frame: Single-dose phase (Part 1): Up 24 hours post-dose; multiple-dose phase (Part 2): Through 24 hours post first and second dose
Single-dose phase (Part 1): Up 24 hours post-dose; multiple-dose phase (Part 2): Through 24 hours post first and second dose
PK of SRP-1003: Area Under the Plasma Concentration Versus Time Curve from Zero to Infinity (AUCinf)
Time Frame: Single-dose phase (Part 1): Up 24 hours post-dose; multiple-dose phase (Part 2): Through 24 hours post first and second dose
Single-dose phase (Part 1): Up 24 hours post-dose; multiple-dose phase (Part 2): Through 24 hours post first and second dose

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sarepta Therapeutics, Inc.

Investigators

  • Study Director: Medical Director, Sarepta Therapeutics, Inc.

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

March 4, 2024

Primary Completion (Estimated)

December 31, 2026

Study Completion (Estimated)

December 31, 2026

Study Registration Dates

First Submitted

November 14, 2023

First Submitted That Met QC Criteria

November 14, 2023

First Posted (Actual)

November 18, 2023

Study Record Updates

Last Update Posted (Actual)

August 11, 2026

Last Update Submitted That Met QC Criteria

August 7, 2026

Last Verified

August 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • SRP-1003-101
  • 2024-513579-42 (EudraCT Number)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

Yes

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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