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

Status

Indicates the current recruitment status or the expanded access status.
Recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
78

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • 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

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.
  • 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

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

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

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
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

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
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

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
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

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Sarepta Therapeutics, Inc.

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • 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)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
March 4, 2024

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
December 31, 2026

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
December 31, 2026

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
November 14, 2023

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
November 14, 2023

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
November 18, 2023

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
August 11, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
August 7, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
August 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant 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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