The Efficacy and Safety of Metoprolol as add-on Treatment to Standard of Care in Preventing Cardiomyopathy in Patients With DMD

The study includes 150 patients with DMD diagnosis confirmed by genetic testing, 8-16 years old (≥8 and \<17) at the study entry with a follow-up of up to 5 years. Random enrollment of a patient to one of two groups (intervention or control) takes place after pre-screening and screening stage starts the first phase of the trial. To be eligible for participation in the study, patients must receive standard of care cardiac therapy, which is an Angiotensin-converting-enzyme inhibitor (ACEi) for at least one-month prior to enrollment. A major part of the trial is equal for all patients - who will be receiving indistinguishable investigational medicinal products (IMPs), the drug metoprolol succinate or placebo. As a part of the clinical trial, diagnostic examinations evaluating progression of the disease, will be performed periodically. In addition, all patients will be monitored at home. Heart rate, blood pressure and patients' personal well-being will be controlled using telemedicine technologies. Additional visits in the research center will be provided if any adverse events occur. This model will be continued for 30 months from the enrollment of a first patient. After this period the first drug efficiency analysis will be performed. After that, the intervention may be continued or in case of negative impact of the intervention on patients' health and well-being, terminated with further patients monitoring.