First in Human SAD/MAD Safety and PK Study With Adult DMD Safety and PK Cohort

Parts A-C enroll healthy volunteers; only entry criteria for Part D are described below.

Part D Inclusion Criteria:

• Able and willing to provide written informed consent after the nature of the studyhas been explained and prior to the commencement of any study procedures.

• Considered reliable and capable of adhering to the protocol and able and willing toattend the necessary visits to the study site according to the judgment of the PI ordesignee.

• Male patients ≥18 to ≤ 40 years (inclusive at the time of informed consent), orconsidered an adult able to consent to participate in a clinical study in thejurisdiction in which the study is being conducted.

• Non-smoker and must not have used any tobacco or cannabis products within 2 monthsprior to Screening.

• Has a definitive diagnosis of DMD based on documented clinical findings and priorgenetic testing with a confirmed mutation in the DMD gene.

• BMI ≥ 18.0 kg/m2 and ≤ 32.0 kg/m2 and weight ≥ 50 kg at Screening.

• Stable dose of systemic glucocorticosteroids, heart medications, and/or othersupportive medications, vitamins and supplements according to the standard of carefor DMD for 3 months prior to the Screening visit and for the duration of the study.Participants that are not receiving glucocorticosteroids are also eligible, but mustrefrain from initiating glucocorticosteroid treatment for the duration of the trial.

• Agree to abstain from donating blood or blood products during the study and for upto 3 months after the administration of the IP.

Part D Exclusion Criteria:

• Underlying psychological condition or history of any mental illness that, in theopinion of the PI or designee, would make it unlikely for the participant to complywith the protocol or complete the study per protocol.

• Presence of acute or chronic illness or history of chronic illness sufficient toinvalidate the patient's participation in the study or make it unnecessarilyhazardous in the judgment of the PI.

• Any clinically significant medical, surgical, or psychiatric abnormality that, inthe judgment of the Investigator, is likely to interfere with study compliance, thesafe participation of the subject or the assessment of safety or efficacy.

• Any surgical procedures (eg, stomach bypass) or medical condition that might affectabsorption of medicines.

• Has donated blood within 60 days of IP administration or donated plasma within 7days of IP administration or experienced loss of blood ≥500 mL within 2 months of IPadministration.

• Fever (body temperature >38°C) or symptomatic viral or bacterial infection within 2weeks prior to Screening.

• Poor pill swallowing ability as determined by PI.

• Presence or history of severe allergic or anaphylactic reactions, or sensitivity tothe IP or its constituents.

• History of relevant atopy including any confirmed significant allergic reactionsagainst any drug, or multiple drug allergies (non-active hay fever is acceptable).

• History of malignancy, except for non-melanoma skin cancer excised more than 2 yearsprior to Screening and cervical intraepithelial neoplasia that has been successfullycured more than 5 years prior to Screening.

• Abnormal ECG findings at Screening and or Day -1 that are considered by the PI ordesignee to be clinically significant.

• QT value, measured at Screening visit, greater than 450 msecs (male) on 12-lead ECG,using Fridericia's formula (QTcF) for correction.

• Pulse ≤ 45 or ≥ 100 beats per minute (bpm); systolic blood pressure ≤ 90 mmHg or ≥ 160 mmHg, or diastolic blood pressure ≤ 50 mmHg or > 95 mmHg at Screening.

• History or presence of a condition associated with significant immunosuppression.

• History of life-threatening infection (eg, meningitis).

• Infections requiring parenteral antibiotics within 6 months prior to Screening.

• Positive test for hepatitis C antibody (HCV), hepatitis B surface antigen (HBsAg),human immunodeficiency virus (HIV) antibody.

• Vaccination with a vaccine within 28 days prior to the first administration of IP.

• Creatine kinase > ULN or ALP, AST, bilirubin, and/or ALT >1.5 × ULN at Screening.

• Anticipated change to prescription medication, over the counter medications,vitamins, supplements, and/or herbal remedies during the course of the trial.

• Anything that the PI or designee considers would jeopardize the safety of theparticipant, prevent complete participation in the study (including the possibilitythat the participant will not cooperate with the requirements of the protocol) orcompromise interpretation of the study data.

• An employee, consultant, and/or immediate family member (ie, first degree relative,spouse, adoptees, or legal dependents) of the site, Sponsor, or the CRO.