Patient case (clinical description): An 8-year-old boy is brought to the clinic by his parents because of weakness and difficulty of standing up from a sitting position. The mother is healthy but had a brother who died in his 20th after being disabled and using wheelchairs in the last few years of his life. Physical examination shows 3/5 lower extremity muscle strength and enlarged calf muscles. The other physical examination and vital signs are unremarkable. Muscle biopsy showed absence of dystrophin protein. The patient is diagnosed with DMD.

Patient's own account: I brought my  8-year-old son to the doctor's clinic. He was struggling to stand up from a chair for the past few days. My wife is healthy but she was pretty worried since his brother died in his 20s after being disabled and using a wheelchair for the last years of his life. The doctor did an exam which highlighted weakness in the leg muscles and unusually large calf muscles. The rest of the exam was fine, and his vitals were normal. My son did a muscle biopsy, and it showed that the protein important for muscle strength and function is missing. The doctor diagnosed him with Duchenne muscular dystrophy.

Clinical trial: The Expanded Access Use of Viltolarsen in Duchenne Muscular Dystrophy With Confirmed Exon 53 Amenable Mutation

Eligibility criteria:
Inclusion Criteria:

          -  Male ≥ 3 and ≤ 12 years of age

          -  Clinical signs compatible with DMD

          -  Confirmed DMD mutation(s) in the dystrophin gene that is amenable to skipping of exon
             53 to restore the dystrophin messenger ribonucleic acid (mRNA) reading frame

          -  Able to walk independently without assistive device

          -  Not able to participate in a Phase 3 trial

        Exclusion Criteria:

          -  Chronic systemic fungal or viral infections

          -  An acute illness within 4 weeks prior to the first dose of viltolarsen

          -  Symptomatic cardiomyopathy

          -  Patient has a previous or ongoing medical condition, medical history, physical
             findings, or laboratory abnormality that could affect participant safety in the
             opinion of the treating physician

          -  Surgery within the 3 months prior to the first anticipated administration of
             viltolarsen and in the opinion of the treating physician would impact weekly treatment
             schedule

          -  Positive test results for hepatitis B antigen, hepatitis C antibody, or human
             immunodeficiency virus (HIV) antibody at screening

          -  Currently taking any other investigational drug or has taken any other investigational
             drug within 3 months prior to the first dose of viltolarsen

          -  Previously enrollment in any viltolarsen study.

          -  Currently taking any other exon skipping agent or has taken any other exon skipping
             agent within 2 weeks prior to the first dose of viltolarsen (would need to be
             discontinued in order to be eligible)

          -  Any gene therapy for DMD

          -  Inadequate renal function as defined by a serum cystatin C > 1.5 x upper limit of
             normal (ULN). If the value is > 1.5 x ULN then the measurement can be repeated once.
             If repeat measurement is still > 1.5 x ULN then the patient should be excluded.
Male

Subject must be at least 3 Years old.
Subject must be at most 12 Years

Eligibility (NLI label): Entailment