This is a prospective observational study conducted to evaluate safety, tolerability, and functional outcomes of patients with DMD newly initiating oral givinostat or having started therapy within 6 months as part of routine clinical care in the US. The study has a planned maximum duration of 5 years for the first enrolled patients, including a 24-month enrollment period and a minimum of 2 years of follow-up.

Duchenne Muscular Dystrophy (DMD) is a rare genetic disorder that leads to progressive muscle degeneration and weakness. Givinostat, an oral histone deacetylase inhibitor, was approved by the FDA in March 2024 for treatment of DMD in patients aged 6 years and older, regardless of mutation type.

Study participation will not influence the course of treatment in any way (including other treatments for DMD), and no treatment will be provided as part of this study. All assessments are intended to be performed at the time of a routine clinical care visit according to clinical practice, and data will be extracted from the medical records.

The FDA is requiring a post-marketing prospective study be conducted for a minimum of 5 years to characterize the incidence, frequency, and severity of thrombocytopenia and serious events of bleeding in patients with DMD treated with oral givinostat in routine clinical practice.

This study is designed as a prospective, observational study to assess safety (including evaluation of AEs of special interest [AESIs]) and effectiveness, in patients with DMD newly initiating oral givinostat as part of routine clinical care in the US in a real-world population. The study will assess AESIs noted above, as well as serious adverse events (SAEs), gastrointestinal (GI) AEs, and dehydration as a sequela to GI AEs. Real-world-treatment patterns of DMD treatments (corticosteroids, exon skipping oligonucleotides and gene therapy) prior to and after givinostat initiation, including treatment duration, and treatment combinations, will be described. Effectiveness evaluations will characterize motor function, quality of life, and activities of daily living in DMD patients treated with givinostat.

The study will enroll 300 participants (180 non-ambulatory and up to 120 ambulatory patients). Participants will be followed for at least two years, with data collected during routine clinical visits. Assessments include lab parameters (e.g., platelet counts, triglycerides), cardiac and pulmonary function, patient-reported outcomes, and motor function scales such as the North Star Ambulatory Assessment (NSAA) and Performance of Upper Limb (PUL) scale.

Inclusion Criteria:

• Patients of any gender at least 6 years of age, diagnosed with DMD (according to genetic test) and have received a prescription for oral givinostat in accordance with the USPI.
• Patient has provided informed consent (and assent when applicable) for participation in the study.
• Patient's index date (first date of givinostat treatment) is no more than 6 months prior to signing of informed consent.
• Patient has the required data available (DMD diagnosis, givinostat administration [dose and schedule], laboratory results [hematology and triglycerides]) for addressing the study objectives for the period between index date and study entry (for patients enrolled after the index date).

Exclusion Criteria:

• Patient previously received givinostat (commercial or investigational product) and permanently discontinued treatment or patient started commercial givinostat for > 6 months before signing of informed consent.

This study will be conducted in the US and plans to enroll 300 patients diagnosed with DMD and treated with givinostat as part of their routine clinical care. Patients will be recruited from expert centers treating DMD patients with specialists in neuromuscular conditions who are routinely involved in the care and treatment of patients with DMD, some of whom would have already gained experience with givinostat.