Let’s sail through Duchenne Muscular Dystrophy (DMD) research together!

The EXPLORE44™ study is focused on testing a new investigational drug as a treatment option for Duchenne Muscular Dystrophy (DMD). If you are 7 to 27 years old with a diagnosis of DMD due to a mutation amenable to exon 44 skipping, consider coming aboard this study to evaluate an investigational drug that is designed to treat the underlying cause of DMD.

About the Study

The EXPLORE44™ study will evaluate the safety, tolerability, and effectiveness of a new investigational medication in eligible individuals with DMD mutations amenable to exon 44 skipping.


You may be eligible to participate if you are 7 to 27 years old and have been diagnosed with DMD and have a mutation amenable to exon 44 skipping.

Study Locations

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

Who Is Eligible to Participate in This Study?

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

  • Are male and between the ages of 7 to 27 years
  • Have been clinically diagnosed with DMD or had a clear onset of DMD symptoms at or before the age of 6 years old
  • Have a gene mutation amenable to exon 44 skipping
  • Weigh ≥ 23 kg (50.7 lbs.)
  • Ambulatory or non-ambulatory
  • Currently taking stable doses of steroids or not taking steroids

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

What is Duchenne Muscular Dystrophy (DMD)?

DMD, also known as Duchenne Muscular Dystrophy, is a rare genetic condition that causes gradual degeneration and weakness of muscles including the heart due to the DMD gene failing to produce a protein called dystrophin.
Dystrophin keeps the muscle cells intact. When there is a lack of dystrophin protein, the muscle fibers break down and turn into fatty tissue which causes the muscle to weaken. DMD can be confirmed by a genetic test or muscle biopsy.

DMD almost always occurs in boys, and signs can start to appear between 1 and 3 years of age. Muscles in the lower body, like calf and thigh muscles, are usually affected first. As DMD progresses, muscle weakness can affect the ability to do everyday tasks including walking and ultimately impacts life expectancy due to weakness of the breathing muscles and the heart.

Even though there has been no cure yet, there are therapies that can help manage DMD.

Common symptoms may include:

  • Muscle weakness
  • Difficulty running, jumping, climbing stairs
  • Falling
  • Difficulty rising from a sitting position
  • Muscle pain or stiffness
  • Enlarged calf muscles

About the EXPLORE44™ Study

The EXPLORE44™ 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 DMD community; and is focused on finding out how safe the investigational study drug is for treating DMD in children and adults. The study will look at how the drug is metabolized by the body and effectiveness of the drug compared to placebo for increasing exon skipping and dystrophin levels in muscle biopsies. The study will also collect measures of ambulation, muscle function, and pulmonary function.

How Does the Investigational Study Drug Work?

Avidity has developed a new method that is designed to deliver exon-skipping oligonucleotides to the muscles and to the heart using a monoclonal antibody. This method is expected to increase dystrophin by achieving higher levels of exon skipping lasting over a longer period of time than using exon skipping oligonucleotides alone.

For more information on exon skipping see:

To learn more about how the study drug works, please visit Avidity’s website: https://www.aviditybiosciences.com/pipeline/dmd/

What to Expect During the EXPLORE44™ Study

To participate in this study, participants 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 to withdraw from the study
Approximately 24 DMD patients will take part in the EXPLORE44™ study in the US and Canada.
After confirming eligibility, participants enrolled in the study will be randomly assigned to receive either the investigational drug or placebo. Participants will have a greater chance of receiving the active drug. For every 8 participants, 6 will receive the investigational drug and 2 will receive a placebo. Thus, participants will have a 75% chance of receiving the investigational drug and a 25% chance of receiving a placebo.

Both investigational drug and placebo will be given by intravenous infusions approximately either every 6 or 8 weeks. The study is blinded, meaning that neither you nor the study team will know which study treatment you are receiving. However, the study doctor can quickly find out if there is a medical need.

Safety is our top priority, and that’s why study teams will monitor the health of all participants closely. We’ll make sure participants are doing well through various procedures and checks.

Some of the planned assessments and procedures include:

  • Health Questions
  • Physical Examinations
  • Vital Signs
  • Blood and Urine Sample Collections
  • Electrocardiogram (ECG)
  • Spirometry
  • Echocardiogram
  • Skeletal Muscle Open Biopsies
  • Genetic Testing
  • Muscle Function Tests
  • Patient/Caregiver Reported Outcomes

Participants will be enrolled in the EXPLORE44™ study for up to 8 months, including screening.

Each participant will take part in a screening period of up to 6 weeks, followed by a study treatment period of approximately 12 or 16 weeks (dependent upon 6 or 8 week infusion schedule), and a 4-week Post-treatment Follow-up.

Avidity Biosciences is also planning an Open-Label Extension (OLE) study, in which all eligible participants who have completed the EXPLORE44™ study will receive the active study drug for an ongoing period.

Participants who do not immediately take part in or decline the OLE will be followed for another 2 months in an Extended Follow-up Period as part of the EXPLORE44™ study.

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

See if You or Someone You Know Qualify for This Study

Fill out the form below to help determine eligibility.

If you are interested in learning more about this study opportunity, please complete the following questionnaire. With your consent, an EXPLORE44™ study site representative will contact you to discuss any additional eligibility requirements, as well as where the study is taking place. Your information will never be shared with a third-party vendor.

"*" indicates required fields

Has a healthcare professional diagnosed the potential participant with a DMD mutation amenable to exon 44 skipping? Please complete this statement. The intended participant:
Preferred Contact Time:
Preferred Contact Method:
This field is for validation purposes and should be left unchanged.

Frequently Asked Questions

What is the purpose of a clinical trial?

The main purpose of a clinical trial is to gather information on the safety and efficacy of an investigational medication. The data collected during the trial helps to determine whether the investigational medication should be approved for general use and can also provide essential information on potential side effects and risks.

Why participate in a clinical trial?
Participation in clinical trials 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.
What is an investigational medication?
An investigational medication 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 the investigational medication but does not contain any active ingredients.
What are my rights as a participant and what will happen if I decide 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 the investigational medication and this study?
More information on this clinical trial can be found on clinicaltrials.gov.

Where We Are

Study Site Locations

Current study locations are listed below and more may be added at any time. If you are interested in participating in the EXPLORE44™ study, complete the form to speak with a study site representative regarding your eligibility. If you don’t see a site near you but would be willing to travel, travel assistance may be made available for participants and their caregivers.

      For interested participants or caregivers:

      For more information on this study please visit clinicaltrials.gov.

      To share this study by email, click here.

      For physicians and healthcare providers:

      Are you a physician looking to refer a patient to the EXPLORE44™ study?

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