Myotonic Dystrophy Type 1Phase 3HARBOR-OLENCT07008469
Global Open-Label Extension Study of Del-desiran for the Treatment of DM1
A Phase 3 study testing Del-desiran (AOC 1001) in people with Myotonic Dystrophy Type 1 and DM1, run by Avidity Biosciences, Inc. at 35 sites in 10 countries.
Trial summary
A Global Phase 3 Open-Label Extension Study to Assess the Long-Term Safety, Tolerability, and Efficacy of Intravenous Delpacibart Etedesiran (abbreviated del-desiran, formerly AOC 1001) for the Treatment of Myotonic Dystrophy Type 1 Read more about this study
- Who is it for?
- Ages 16 years and older
- Conditions the study is for
- Myotonic Dystrophy Type 1, DM1, Myotonic Dystrophy
- What is being tested?
- Del-desiran (AOC 1001)
- Type of treatment
- Injection or infusion
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 199 participants
- Where
- 35 sitesin 10 countries
- Study dates
- 26 Jun 2025to Oct 2030
- Phase
- Phase 3
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 16 years and older
- All sexes
- No healthy volunteers
- Child, Adult, Older adult
Who may be able to join
- Completion of any prior AOC 1001 studies with satisfactory completion of dosing and follow-up assessments and satisfactory compliance with the protocol requirements of the parent study, as determined by the Investigator.
- Clinical and genetic diagnosis of DM1 and clinically significant hand myotonia.
Who cannot join
- Breastfeeding, pregnancy, or intent to become pregnant during the study.
- Unwilling to comply with contraceptive requirements.
- Any new conditions or worsening of existing condition that in the opinion of the Investigator would make the participant unsuitable for the study.
- FIXED-DOSE PK COHORT
- Breastfeeding, pregnancy, or intent to become pregnant during the study
- Unwilling to comply with contraceptive requirements
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- Abnormal lab values, conditions or diseases that would make the participant unsuitable for the study
- Diabetes that is not adequately controlled
- History of decompensated heart failure within 3 months of screening. Participants with preexisting pacemaker/ICD are not excluded
- Body Mass Index > 35 kg/m2 at Screening
- Recently treated with an investigational drug or biological agent
- Note: Additional protocol defined Inclusion and Exclusion criteria apply
Trial locations and contacts
35 sites in 10 countries. Contact the study team or a site near you to ask about taking part.
35 sites in 10 countries
United States19 sites
Kennedy Krieger Institute
Baltimore, Maryland, 21205
Beth Israel Deaconess Medical Center
Boston, Massachusetts, 02215
University of Cincinnati Gardner Neuroscience Institute
Cincinnati, Ohio, 45219
Ohio State University
Columbus, Ohio, 43221
University of Colorado
Denver, Colorado, 80045
Duke University Medical Center
Durham, North Carolina, 27708
University of Florida
Gainesville, Florida, 32608
Houston Methodist Neurological Institute
Houston, Texas, 77030
Indiana University (IU)
Indianapolis, Indiana, 46202
Kansas University Medical Center
Kansas City, Kansas, 66205
University of California, Los Angeles (UCLA)
Los Angeles, California, 90095
University of Minnesota
Minneapolis, Minnesota, 55455
University of Pennsylvania
Philadelphia, Pennsylvania, 19104
Virginia Commonwealth University
Richmond, Virginia, 23298
University of Rochester Medical Center
Rochester, New York, 14642
University of Washington
Seattle, Washington, 98104
Stanford University
Stanford, California, 94305
University Research Center of South Florida
Tampa, Florida, 33612
Wake Forest
Winston-Salem, North Carolina, 27157
Japan4 sites
Aomori Hospital
Aomori, Aomori, 038-1331
National Hospital Organization Osaka Toneyama Medical Center
Osaka, 560-8552
Osaka University Hospital
Osaka, 565-0871
National Center of Neurology and Psychiatry
Tokyo, 187-8551
Canada2 sites
Montreal Neurological Institute
Montreal, Quebec, H3A 2B4
The Ottawa Hospital
Ottawa, Ontario, K1Y 4E9
Denmark2 sites
Aarhus University Hospital
Aarhus, 8200
Rigshospitalet
Copenhagen, 2100
Netherlands2 sites
Maastricht University Medical Center
Maastricht, 6229 HX
Stichting Radboud Universitair Medisch Centrum
Nijmegen, 6525 GA
United Kingdom2 sites
University College London Hospital
London, NW1 2BU
St. Georges University Hospitals NHS Foundation Trust
London, SW17 0QT
Germany1 site
Klinikum der Ludwig-Maximilians-Universitaet Muenchen
München, 80336
About this study
Official title: A Global Phase 3 Open-Label Extension Study to Assess the Long-Term Safety, Tolerability, and Efficacy of Intravenous AOC 1001 for the Treatment of Myotonic Dystrophy Type 1
A Global Phase 3 Open-Label Extension Study to Assess the Long-Term Safety, Tolerability, and Efficacy of Intravenous Delpacibart Etedesiran (abbreviated del-desiran, formerly AOC 1001) for the Treatment of Myotonic Dystrophy Type 1
Read the detailed description
The study consists of a Screening Period of up to either 4-weeks or 8-weeks depending on the prior parent trial, and up to a 4-year Treatment Period. The anticipated duration is 50 months and 2 weeks (4 years and 2.5 months).
Participants will receive an intravenous infusion of del-desiran at the clinical study site every 8 weeks for a total of 7 doses per year. The final dose will occur at Year 4, Visit 7, followed by a final assessment 8 weeks after the last dose.
An additional subgroup of de novo participants will also be included in a Fixed-Dose PK cohort.
An Independent Data Monitoring Committee (IDMC) comprised of members independent and external to the Sponsor will review safety, tolerability, and efficacy (as needed) data of this study at regular intervals.
- Conditions
- Myotonic Dystrophy Type 1, DM1, Myotonic Dystrophy, Myotonia, Myotonic Dystrophy 1, Myotonic Disorders
- Being tested
- Del-desiran (AOC 1001)
- Keywords
- DM1, Myotonic Dystrophy, Myotonic Dystrophy 1, Myotonia, Myotonic Dystrophy Type 1 (DM1), Dystrophy Myotonic, Myotonic Disorders, Steinert Disease, Steinert, Myotonic Muscular Dystrophy, HARBOR-OLE, Avidity Biosciences, Avidity, AOC 1001, Del-desiran, Delpacibart etedesiran, HARBOR
- Medical subject headings
- Myotonic Dystrophy, Myotonia, Myotonic Disorders
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Del-desiran (AOC 1001)Drug
Del-desiran will be administered by intravenous (IV) infusion.
| Study group | Role | What they receive |
|---|---|---|
| Del-desiran | Experimental | Del-desiran (AOC 1001) will be administered seven times per year for up to 4 years. Receives: Drug: Del-desiran (AOC 1001) |
What is being measured
The primary outcome is the main question the study is designed to answer.
TEAEs
Incidence of treatment emergent adverse events
Measured: From enrollment to the end of treatment at 4 years
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted6 Jun 2025
- Study start26 Jun 2025
- Primary completionOct 2030 (estimated)
- Study completionOct 2030 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Myotonic Dystrophy Type 1Studies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 3
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Enrolment
- 199 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Avidity Biosciences, Inc.
- Sponsor type
- Industry (pharma, biotech, devices)
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07008469
- Sponsor's protocol ID
- AOC 1001-CS4
- Acronym
- HARBOR-OLE
- Status last verified
- Aug 2026
- First submitted
- 29 May 2025
- Last updated
- 19 Aug 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- Undecided: Not yet determined
Study at a glance
From the registry record, last updated by the sponsor on 19 Aug 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- A Global Phase 3 Open-Label Extension Study to Assess the Long-Term Safety, Tolerability, and Efficacy of Intravenous AOC 1001 for the Treatment of Myotonic Dystrophy Type 1
- ClinicalTrials.gov ID
- NCT07008469
- Acronym / sponsor ID
- HARBOR-OLE / AOC 1001-CS4
- Conditions
- Myotonic Dystrophy Type 1, DM1, Myotonic Dystrophy, Myotonia, Myotonic Dystrophy 1, Myotonic Disorders
- Keywords
- DM1, Myotonic Dystrophy, Myotonic Dystrophy 1, Myotonia, Myotonic Dystrophy Type 1 (DM1), Dystrophy Myotonic, Myotonic Disorders, Steinert Disease
- Phase
- Phase 3
- Study type
- Interventional
- Recruitment status
- Enrolling by invitation
- Enrolment
- 199 participants (estimated)
- Lead sponsor
- Avidity Biosciences, Inc.Industry (pharma, biotech, devices)
- Study start
- 26 Jun 2025 (actual)
- Primary completion
- Oct 2030 (estimated)
- Study completion
- Oct 2030 (estimated)
- First posted
- 6 Jun 2025 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
A Global Phase 3 Open-Label Extension Study to Assess the Long-Term Safety, Tolerability, and Efficacy of Intravenous Delpacibart Etedesiran (abbreviated del-desiran, formerly AOC 1001) for the Treatment of Myotonic Dystrophy Type 1
Detailed description
The study consists of a Screening Period of up to either 4-weeks or 8-weeks depending on the prior parent trial, and up to a 4-year Treatment Period. The anticipated duration is 50 months and 2 weeks (4 years and 2.5 months).
Participants will receive an intravenous infusion of del-desiran at the clinical study site every 8 weeks for a total of 7 doses per year. The final dose will occur at Year 4, Visit 7, followed by a final assessment 8 weeks after the last dose.
An additional subgroup of de novo participants will also be included in a Fixed-Dose PK cohort.
An Independent Data Monitoring Committee (IDMC) comprised of members independent and external to the Sponsor will review safety, tolerability, and efficacy (as needed) data of this study at regular intervals.
Study design
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| Del-desiran | Experimental | Drug: Del-desiran (AOC 1001)Del-desiran (AOC 1001) will be administered seven times per year for up to 4 years. |
Who may qualify
- Ages
- 16 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Child, Adult, Older adult
Key inclusion criteria (2 listed)
- Completion of any prior AOC 1001 studies with satisfactory completion of dosing and follow-up assessments and satisfactory compliance with the protocol requirements of the parent study, as determined by the Investigator.
- Clinical and genetic diagnosis of DM1 and clinically significant hand myotonia.
Key exclusion criteria (12 listed)
- Breastfeeding, pregnancy, or intent to become pregnant during the study.
- Unwilling to comply with contraceptive requirements.
- Any new conditions or worsening of existing condition that in the opinion of the Investigator would make the participant unsuitable for the study.
- FIXED-DOSE PK COHORT
- Breastfeeding, pregnancy, or intent to become pregnant during the study
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Del-desiran (AOC 1001)Del-desiran will be administered by intravenous (IV) infusion. | Drug | Del-desiran |
Primary outcome
TEAEs
Time frame: From enrollment to the end of treatment at 4 years
Incidence of treatment emergent adverse events
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 19 Aug 2026.
- Individual participant dataSharing planned: Undecided. Not yet determined
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
The record lists no contact. Use the official record to reach the sponsor.
35 sites in 10 countries: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 3 study testing Del-desiran (AOC 1001) in people with Myotonic Dystrophy Type 1 and DM1, run by Avidity Biosciences, Inc. at 35 sites in 10 countries.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 2 inclusion and 12 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: enrolling by invitation, as of the sponsor's last update on 19 Aug 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 35 sites in United States, Japan, Canada, Denmark, Netherlands and 5 more countries. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 3 studies compare the treatment with the current standard treatment or a placebo in a large group, to confirm how well it works and watch for side effects.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
TEAEs (time frame: From enrollment to the end of treatment at 4 years). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 19 Aug 2026.