Study to Assess the Safety and Efficacy of Viltolarsen in Ambulant Boys With DMD (RACER53-X)
Duchenne muscular dystrophy (DMD) is a genetic condition that gradually weakens muscles over time. This Phase 3 trial, known as RACER53-X, is studying an investigational medicine called viltolarsen. It is an 'extension study' designed specifically for boys who can walk and who have already finished an earlier 48-week trial of the drug. In the previous study, some boys received the medicine while others received a dummy treatment (placebo). In this study, there is no dummy treatment. Every boy who takes part will receive viltolarsen. The medicine is given once every week as a drip into a vein (an intravenous infusion) for 96 weeks, which is just under two years. Researchers want to see how safe viltolarsen is over a longer period and whether it helps slow down muscle weakness. Taking part is entirely voluntary, and families can leave at any time.
At a glance
What is this study about?
Duchenne muscular dystrophy (DMD) is a rare condition that mainly affects boys. It is caused by a change in a gene that normally produces dystrophin, an important protein that protects muscles from damage. Without enough working dystrophin, muscles slowly weaken over time, making it harder to walk, run, and carry out everyday activities.
Viltolarsen is an experimental medicine designed to help the body skip over a missing or faulty section of the dystrophin gene. This helps the body produce a shorter but working version of the dystrophin protein, which researchers hope will help protect muscles and keep children walking for longer.
This study, called RACER53-X, is an extension trial. It offers boys who took part in a previous 48-week study the chance to receive viltolarsen for another 96 weeks (nearly two years). Because this is an 'open-label' study, all participants receive the active medicine, with no dummy treatments used. The study helps doctors learn more about the medicine's long-term safety and whether it continues to help muscle strength over time.
Key takeaways
- This study is an extension trial for boys with DMD who completed the earlier RACER53 study.
- All participants receive the study medicine; there is no dummy treatment (placebo).
- The medicine is given as a weekly drip into a vein over a period of 96 weeks.
- The main goals are to check long-term safety and see if the drug helps maintain walking ability.
- Participation is entirely voluntary, and families can withdraw at any time.
Who may be eligible?
This study is only open to boys who have already taken part in and completed the earlier trial of viltolarsen (Study NS-065/NCNP-01-301). To take part, boys must still be able to walk, and both the child and their parents or guardians must be able to attend regular hospital visits for treatments and checks.
Boys cannot take part if they had serious side effects during the first trial that made continuing unsafe. They also cannot join if they have taken any other experimental drugs or treatments aimed at boosting dystrophin levels since finishing the earlier study.
The study doctor will review each child's health history to confirm whether joining the extension study is safe and suitable for them.
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.
- My child is male and has Duchenne muscular dystrophy.
- My child successfully completed the previous study (NS-065/NCNP-01-301).
- My child is still able to walk.
- My child has not started any other experimental drugs since the last study ended.
- Our family can commit to weekly clinic visits for nearly two years.
What does participation involve?
Taking part in the study lasts for 96 weeks, which is about 22 months. Boys will need to visit the study hospital once a week to receive viltolarsen. The medicine is given as a drip into a vein (an intravenous infusion), with each dose based on the child's body weight. During visits, the medical team will carry out regular health checks. These may include physical examinations, simple walking and movement tests, blood tests, and heart or breathing checks to see how the child is doing and monitor for any side effects.
Potential risks and benefits
Locations (31)
- Queensland Children's HospitalVerified postcodeBrisbane, Australia
- The Childrens Hospital at WestmeadVerified postcodeWestmead, Australia
- CHU de Quebec Research CentreVerified postcodeQuébec, Canada
- Hospital de Niños Roberto del RioVerified postcodeSantiago, Chile
- Pontificia Universidad Católica de ChileVerified postcodeSantiago, Chile
- Chinese PLA General HospitalVerified postcodeBeijing, China
- Hunan Children's HospitalVerified postcodeChangsha, China
- Children's Hospital of Fudan UniversityVerified postcodeShanghai, China
- Shenzhen Children's HospitalVerified postcodeShenzhen, China
- Fakultni nemocnice Hradec KraloveVerified postcodeNový Hradec Králové, Czechia
- Agia Sofia Children's HospitalVerified postcodeAthens, Greece
- Hippokration General Hospital of ThessalonikiVerified postcodeThessaloniki, Greece
Common questions
What is an extension study?
An extension study allows people who finished an earlier clinical trial to continue receiving treatment so researchers can learn more about its long-term safety and benefits.
Will my child receive a dummy treatment (placebo)?
No. In this extension trial, there is no dummy treatment. Every boy who takes part will receive the active medicine, viltolarsen.
How is the medicine given?
Viltolarsen is given once a week through a drip into a vein, usually at the study clinic or hospital.
Can we stop taking part if we change our minds?
Yes. You and your child are free to leave the trial at any time, for any reason, and your regular medical care will not be affected.
Does viltolarsen cure Duchenne muscular dystrophy?
No, it is not a cure. It is designed to help the body make a working form of the missing muscle protein to help slow down muscle weakness.
How to find out more
Always speak to your GP or specialist before deciding to take part in a study.
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