Enrolling by Invitation

NCT Number: NCT07008469

Global Open-Label Extension Study of Del-desiran for the Treatment of DM1

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

Enrolling by Invitation

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Key information

Conditions

Myotonic Dystrophy Type 1 Congenital, Hereditary, and Neonatal Diseases and Abnormalities DM1 Genetic Diseases, Inborn Heredodegenerative Disorders, Nervous System Muscular Diseases Muscular Disorders, Atrophic Muscular Dystrophies Musculoskeletal Diseases Myotonia Myotonic Disorders Myotonic Dystrophy Myotonic Dystrophy 1 Nervous System Diseases Neurodegenerative Diseases Neurologic Manifestations Neuromuscular Diseases Neuromuscular Manifestations Pathological Conditions, Signs and Symptoms Signs and Symptoms Steinert Disease Steinert Myotonic Dystrophy

Age range

16 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Phase 3

Primary location

The Ottawa Hospital, Ottawa, Ontario, Canada

About this study

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.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

FROM A PARENT STUDY

Key Inclusion Criteria:

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.

Key Exclusion Criteria:

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

Key Inclusion Criteria:

Clinical and genetic diagnosis of DM1 and clinically significant hand myotonia.

Key Exclusion Criteria:

Breastfeeding, pregnancy, or intent to become pregnant during the study
Unwilling to comply with contraceptive requirements
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

Treatment and study plan

Del-desiran (AOC 1001)

Drug

Del-desiran will be administered by intravenous (IV) infusion.

Primary outcomes

TEAEs

Time frame: From enrollment to the end of treatment at 4 years

Incidence of treatment emergent adverse events

Sponsors and collaborators

Lead sponsor

Avidity Biosciences, Inc.

Industry

Registry information

Official study 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

Acronym: HARBOR-OLE

Important dates

Study start: 2025
Primary completion: 2030
Study completion: 2030
First posted: Jun 6, 2025
Registry last updated: Jul 23, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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