HARBORing Innovation:

Charting the Course for People with Myotonic Dystrophy Type 1

The HARBOR™ study is a Phase 3 global study focused on testing del‑desiran (formerly AOC 1001) which treats the underlying cause of DM1. If you live with DM1, you could help advance treatment options by participating in the HARBOR™ study.

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About the Study

The HARBOR™ study will evaluate the safety, tolerability, and effectiveness of del‑desiran in eligible individuals with DM1.

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What to Expect

Patients will be enrolled in the HARBOR™ study for approximately 14 months, including screening. An Open‑Label Extension study is also planned.

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Study Locations

This study will take place at multiple clinical sites in several countries. Click here to view our map and find a participating site location near you.

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Who is Eligible to Participate in This Study?

You or a loved one may qualify if you or they:

  • Are 16 to 65 years old
  • Have a clinical and genetic diagnosis of DM1
  • Are able to walk independently (orthoses and ankle braces allowed) for at least 10 meters
  • Are willing and able to follow contraceptive guidelines, and are not currently pregnant, breastfeeding, or planning to become pregnant during the study

Additional requirements to participate will apply. A study representative will discuss them with you prior to or during the Screening Visit.

Study Site Locations

What is Myotonic Dystrophy Type 1 (DM1)?

DM1 is a neuromuscular disease that impacts multiple organ systems, including skeletal and smooth muscle, the heart, eyes, and the endocrine and central nervous systems. It is caused by an expansion of CUG triplet repeats in the myotonic dystrophy protein kinase (DMPK) gene. In healthy individuals, the number of these repeats is typically around 35, but in those with DM1, there can be thousands of repeats.

The progression of DM1 varies greatly among individuals, but symptoms generally progress gradually.

The most common type of DM1 begins in adolescence or young adulthood, often with weakness in the muscles of the face, neck, fingers, and ankles. This weakness slowly progresses to other muscles over time.

While there is no cure yet, various therapies can help manage DM1 and alleviate symptoms.

People with DM1 can experience a range of symptoms that can significantly decrease the quality of life and place a substantial burden on caregivers.

Source: https://www.mda.org/disease/myotonic-dystrophy

Common symptoms may include:

  • Head, neck, and face muscle weakness
  • Difficulty relaxing muscles, leading to stiffness
  • Mobility issues
  • Breathing & swallowing difficulties
  • Gastrointestinal Issues
  • Extreme fatigue & daytime sleepiness
  • Memory problems & difficulty concentrating
  • Cataracts
  • Slow and irregular heartbeat

About the HARBOR™ Study

The HARBOR™ global Phase 3 registrational study was designed in partnership with patients, caregivers, advocates, and key physicians in the field to ensure we are best meeting the needs of the DM1 community; and is focused on finding out how effective and safe del-desiran is for treating DM1 in adolescents and adults.

The study is designed to assess del-desiran’s impact on multiple key aspects of DM1 including myotonia, muscle strength, and activities of daily living. This study’s primary outcome will measure the effect of the study treatment on hand function.

What to Expect During the HARBOR™ Study

To participate in this study, patients will be asked to read and sign an Informed Consent Form (ICF). The form explains:

  • The purpose of the study
  • Required study visits and procedures
  • Potential risks and benefits of participation
  • Confidentiality
  • How participant and caregiver personally identifiable information will be used
  • Information on how participation is voluntary

Approximately 150 DM1 patients will take part in the HARBOR™ study in several countries around the world. After confirming eligibility, patients enrolled in the study will be randomly assigned to receive del-desiran or placebo.

One (1) out of every two (2) patients will receive del-desiran while the remainder will receive the placebo, both through intravenous infusions given approximately every 8 weeks.

The study is blinded, meaning that neither you nor the study team will know which study treatment you are receiving.

Find a Study Location

Safety is our top priority, and that’s why study teams will keep a close eye on all patients in the study. We’ll make sure patients are doing well through various procedures and checks. Some of the required procedures include:

  • Health Questions
  • Physical Examinations
  • Vital Signs
  • Pregnancy Testing
  • Blood and Urine Sample Collections
  • Electrocardiogram (ECG)
  • Muscle Strength & Function Testing

Patients who qualify for the treatment period of the HARBOR™ study will participate for approximately 14 months, including screening.

Each patient will take part in a screening period of up to 6 weeks, followed by a study treatment period of approximately 12.5 months.

Avidity Biosciences is also planning an Open-Label Extension (OLE) study (pending regulatory approval), in which all patients, regardless if they received del-desiran or placebo, will have the option to enroll.

Patients who do not immediately take part in or decline the OLE will be followed as part of the HARBOR™ study for approximately 2 months after their last dose in an Extended Follow-up Period.

Travel support and reimbursement for the participant and a caregiver will be provided while participating in the study.

Frequently Asked Questions

What is the purpose of this clinical study?

The main purpose of this clinical study is to gather information on the safety and efficacy of del-desiran. The data collected during the study helps to determine whether the investigational treatment should be approved for general use and can also provide essential information on potential side effects and risks.

Why participate in a clinical study?
Participation in clinical studies has greatly impacted the health and well-being of many individuals. People participate for several reasons, including the desire to be more involved in their own healthcare, the opportunity to try new and innovative therapies before they become widely available, and making a positive impact on the advancement of medical science and the health of future generations.
Will patients be compensated for participating in the HARBOR™ study?
Many clinical studies offer reimbursement for participation, which can help to cover the costs associated with the study such as transportation and time off work. The patient plus one caregiver will be reimbursed for travel related expenses to and from the clinical study site. It’s important to ask about reimbursement for travel and what expenses will be covered before deciding to participate in a clinical trial. In addition to reimbursement for travel expenses, some study sites may have the ability to pay a per visit stipend payment.
What is an investigational treatment?
An investigational treatment has not been approved by regulatory authorities but is allowed to be administered to people for research purposes to understand if it might be a safe and effective treatment for a specific disease.
What is a placebo?
In this study, the placebo is something that looks like del-desiran but does not contain any active ingredients.
What are the rights of a participant and what will happen if a participant decides not to participate?
It is your choice to take part in this research study or not. You can change your mind and stop participating at any time. If you choose to stop, you may be able to still receive care at the clinic. If you’re thinking about stopping or want more information, please talk to the study doctor.
What are my responsibilities while participating in this study?
If you decide to take part in the study, you will be expected to follow the rules and instructions given to you by the study team. If you can’t follow these rules and instructions, you may be asked to leave the study. The study will be closely monitored by the study doctor and will be carried out by trained staff. You will need to share information about your health, both now and in the past, to protect your safety.

It is also recommended that you let your regular doctor know that you’re participating in this study.

How can I learn more about del-desiran and this study?
More information on this clinical study can be found at aviditybiosciences.com or clinicaltrials.gov by searching NCT06411288.

Where We Are

Study Site Locations

Current study locations are listed below and more may be added at any time. If you or someone you know may be interested in participating in the HARBOR™ study, please contact medinfo@aviditybio.com.

      For interested patients or caregivers:

      For more information on this study please visit clinicaltrials.gov and search NCT06411288.

      To share this study by email, click here.

      For physicians and healthcare providers:

      Are you a physician looking to refer a patient to the HARBOR™ study?

      Please contact a study representative at medinfo@aviditybio.com for more information.