A Study to Assess Safety, Tolerability, and PK of EDG-5506 in Healthy Volunteers and Becker Muscular Dystrophy Adults

Inclusion Criteria: * For all potential participants (Healthy volunteers and BMD): Male or for HV: female. For all: adults aged 18 to 55 years at time of consent. * For HVs: Good general health, with no significant medical history, no clinically significant abnormalities on physical exam * For BMD: Diagnosis of BMD based on documentation of mutation(s) in the dystrophin gene and BMD phenotype * For BMD: Ability to ambulate * For all: Weight greater than or equal to 50 kg and BMI less than 33 kg/m2 * For HV: Females must be of non-childbearing potential. * For all: Males with female partners must use a medically accepted contraceptive regimen from first dose through 90 days after the last dose * For all: Non-smoker and must not have used any tobacco products within 3 months prior to the Screening visit. * For all: Able and willing to attend the necessary visits at the study center. Exclusion Criteria: * For all: History of, or physical exam findings indicating clinically significant endocrine, neurological, gastrointestinal, cardiovascular, hematological, hepatic, immunological, renal, respiratory, or genitourinary abnormalities or diseases that, in the opinion of the Investigator, would render the subject being unsuitable for the study. * For all: Unable to refrain from strenuous exercise for 3 days prior to check-in and during study. * For all: Participation in any other investigational drug study within 30 days or 5 half-lives (whichever is longer) of dosing in the present study.