AuthorisedTherapeutic exploratory (Phase II)Interventional

An Open-Label Extension Study to Evaluate the Long-term Safety and Efficacy of Weekly Intravenous Infusions of BMN 351 in Participants with Duchenne Muscular Dystrophy Amenable to Exon 51 Skipping

This study is for adult men (18+) with Duchenne muscular dystrophy (DMD) who can benefit from a specific treatment approach called 'Exon 51 skipping'. It's continuing to look at the long-term safety and effectiveness of a medicine called BMN 351. This medicine is given weekly through a drip into a vein. Researchers will carefully check for any side effects and see how the medicine helps with muscle function over time. This is an 'open-label' study, meaning both you and your doctor will know if you are receiving the study medicine. It's an important step in understanding this potential new treatment for DMD.

At a glance

Status

Authorised

Phase

Therapeutic exploratory (Phase II)

Sponsor

Biomarin Pharmaceutical Inc.

Enrolment target

Start

16 Mar 2026

Duchenne Muscular Dystrophy

What is this study about?

Duchenne muscular dystrophy (DMD) is a condition that causes muscles to weaken over time. This study is focusing on a new medicine called BMN 351, which is designed for a specific group of men with DMD who have a particular genetic difference. This difference means their bodies could respond to an approach called 'Exon 51 skipping', which aims to help their bodies make more of a vital protein called dystrophin, which is missing in DMD.

The main aim of this study is to closely watch the long-term safety of BMN 351. This means doctors will be looking carefully for any possible side effects while people are taking the medicine. They will also be checking how well the medicine works over a longer period to see if it helps improve or slow down the muscle weakness associated with DMD.

This study is a follow-on from an earlier study, giving patients who have already benefited from the treatment a chance to continue receiving it. Researchers hope to gather more information to understand how this medication can help men with DMD in the long run. The information gathered will be crucial in deciding if this medicine could become a widely available treatment in the future.

Key takeaways

Targets men 18 and over with specific type of Duchenne muscular dystrophy.
Investigates the long-term safety and effectiveness of medicine BMN 351.
Medicine is given weekly via intravenous drip.
Regular health checks and muscle function assessments are part of the study.
Study is 'open-label', meaning participants know they are receiving the drug.

Who may be eligible?

This study is specifically looking for male participants who are 18 years old or older. There is no upper age limit mentioned for joining this particular study.

To be considered, you must have Duchenne muscular dystrophy. Critically, your specific type of Duchenne muscular dystrophy needs to be 'amenable to Exon 51 skipping'. This refers to a particular genetic makeup that means your body might respond to this type of treatment.

Your doctor will be able to tell you if your Duchenne muscular dystrophy is suitable for 'Exon 51 skipping' treatment based on your genetic tests. They will help determine if you meet all the necessary requirements to take part.

Could this study suit you?

Answer these quick questions to see if you may be eligible. This is a guide only — the research team makes the final call.

Are you male?
Are you 18 years old or older?
Do you have Duchenne muscular dystrophy?
Has your doctor confirmed that your Duchenne muscular dystrophy is suitable for 'Exon 51 skipping' treatment?

Answer every question to see your result.

What does participation involve?

If you join this study, you would receive the study medicine, BMN 351, once a week. This medicine is given through a drip directly into a vein in your arm. Throughout the study, you would have regular check-ups, typically every 24 weeks, to monitor your health and how the medicine is affecting you.

These check-ups would involve various assessments. Doctors will do physical examinations, take blood and urine samples for safety tests, check your heart's electrical activity with an ECG, and look at your heart with an echocardiogram. They will also assess your muscle function and abilities using specific tests and questionnaires, such as the North Star Ambulatory Assessment (NSAA) and the Duchenne Functional Rating Scale (PUL 2.0). The total duration of your participation in this long-term study would be discussed with you by the study team.

Potential risks and benefits

Participating in this study might offer the potential benefit of continuing to receive a promising new medicine for Duchenne muscular dystrophy that could help with your condition. However, like all medicines, BMN 351 may have side effects, ranging from mild to serious, which will be closely monitored by the study team. You will be fully informed of all known risks before you decide to take part. It's important to remember that you are free to withdraw from the study at any time, for any reason, without it affecting your medical care.

Locations (3)

Some site locations are approximate. We're improving this — please verify with the trial team before travelling.

—
Unverified
Spain
—
Unverified
Italy
—
Unverified
Netherlands

Common questions

What is 'Exon 51 skipping'?

It's a way the medicine works for some people with Duchenne muscular dystrophy to help their bodies make a vital muscle protein (dystrophin) that is usually missing.

Will I know if I'm getting the actual medicine?

Yes, this is an 'open-label' study, which means both you and your doctor will know you are receiving the study medicine, BMN 351.

How often would I need to visit the clinic?

You would receive the medicine weekly, and major check-ups typically happen every 24 weeks (about every 6 months).

What kind of tests will I have?

You'll have physical exams, blood and urine tests, heart checks (ECG and echocardiogram), and tests to measure your muscle strength and movement.

Can I stop participating if I want to?

Yes, you can choose to leave the study at any time, and it won't affect your regular medical care.