Repurposing Empagliflozin for DMD-associated Cardiomyopathy in Children 6-18 Years of Age

Inclusion Criteria: * Children or adolescents 6 to 18 years of age with DMD-associated cardiomyopathy, followed either as in- or outpatients, will be eligible for inclusion. * Currently on heart failure medication (any drug or any combination). * Patients should potentially benefit from adding a SGLT2i (as judged by the treating physician and the PI or Co-PI). * Patients need to be on stable medical treatment, defined as no new heart failure drug started over the preceding 2 weeks and no major drug dose modification (apart minor adaptations, like weight adaptations, rounding or formulation changes) during the 2 weeks prior to enrolment. * Adolescents, respectively parents or caregivers of children, capable of giving informed consent. * Ability to tolerate a cardiac MRI investigation without the need of general anaesthesia. Exclusion Criteria: * Inability to understand and go through the informed consent procedure. * Inability to receive medications per os or through a nasogastric tube. * Type 1 or Type 2 Diabetes mellitus or any underlying metabolic disease associated with hypoglycaemias. * Body weight \<15kg. * Current smokers (defined as \>1 cigarette/week). * Use of any other nicotine-delivering product (e.g. nicotine patches). * Any known illicit drug abuse. * Active chronic HBV, HCV or HIV. * Any major surgery within 4 weeks of first dose administration. * Blood transfusion recipient within 4 weeks of dose administration. * eGFR \<45mL/min/1.73m2 (simplified Schwartz formula or Filler formula). * K+ \>6.5mmol/L. * Blood glucose \<4mmol/L. * There are no blood pressure exclusion criteria foreseen, but participants need to be haemodynamically stable, as assessed by the local investigator. * Sustained or symptomatic arrhythmia insufficiently controlled with drug and/or device therapy. * Cardio-surgical procedure within the 2 months prior to Visit 1, or interventional cardiac catheterization within 2 weeks prior to Visit 1, or the patient is planned to undergo cardiac surgery or an interventional cardiac catheterization during the study period (i.e. in the 6 months following Visit 1). * Post-menarchal female patients of childbearing potential cannot be included. Participants who begin menstruating during the trial will be discontinued from the IMP. However, their monitoring will continue up to 6 months after their first dose of IMP. * Known lactose intolerance, galactose intolerance, total lactase deficiency, or glucose-galactose malabsorption. * Known allergies to active ingredients or excipients of commercially available empagliflozin tablets. * Significant medical history of active severe medical disease. * Significant liver disease, Child Pugh Class C, or significant laboratory abnormalities at enrolment. * Significant gastroenterological or hepatic disease that could significantly impair absorption or metabolism of orally administered drugs. * Any medical co-morbidity, which is deemed incompatible (or only with relevant risk) with study participation by the treating clinician and/or the study investigator. * Active urinary tract infection (being treated with antibiotics at the moment of Visit 1) or other relevant bacterial infection, as judged by the treating clinician and/or the study investigator. * The patient is currently participating in another interventional clinical trial or has participated in such a trial during the \<14 days before Visit 1 (or if enrolment in this study is incompatible with the protocol of that preceding trial), or the duration of five half-lives of the IMP, whichever is longer.