Study of AOC 1044 in Healthy Adult Volunteers and Participants With Duchenne Muscular Dystrophy (DMD) Mutations Amenable to Exon 44 Skipping

Part A: Key Inclusion Criteria: * Aged 18 to 55 years, inclusive, at the time of informed consent * Body mass index (BMI) of 18.5 to 32.0 kg/m2 Key Exclusion Criteria: * Clinically significant abnormalities in laboratory results, ECGs, or vitals * Current or recent use of prescription or nonprescription drugs * Positive drug/alcohol test at Screening or Day -1 * Elevated blood pressure (BP) \>130/80 mmHg at Screening * Participation in a clinical study in which an investigational product was received within 1 month of screening or 5 half-lives of the investigational product * Blood or plasma donation within 16 weeks of planned AOC 1044 administration Note: Other protocol defined Inclusion/Exclusion criteria may apply Part B: Key Inclusion Criteria: * Aged 7 to 27 years, inclusive, at the time of informed consent * Clinical diagnosis of DMD or clear onset of DMD symptoms at or before the age of 6 years * Confirmation of DMD gene mutation amenable to exon 44 skipping * Weight ≥ 23 kg * Ambulatory or non-ambulatory * Ambulatory participants: LVEF ≥50% and FVC≥50% * Non-ambulatory participants: LVEF ≥45% and FVC≥40% * PUL 2.0 entry item A ≥3 * If on corticosteroids, stable dose for 30 days before screening and throughout the study Key Exclusion Criteria: * Biceps brachii muscles unsuitable for biopsy * Serum hemoglobin \< lower limit of normal * Uncontrolled hypertension or diabetes * Prior treatment with any cell or gene therapy * Prior treatment with another exon 44 skipping agent within 6 months prior to informed consent * Recently treated with an investigational drug * History of multiple drug allergies