This is a randomized, double-blind, placebo-controlled, parallel-group single ascending dose (SAD) study. There are 4 cohorts of 8 subjects (8 active and 2 placebo) planned for evaluation under fasting conditions. One of the planned dose levels will cross over after a washout period to receive the same single dose of XC101-D13H or placebo under fed conditions.

This is a randomized, double-blind, placebo-controlled, parallel-group single ascending dose (SAD) study. There are 4 cohorts of 8 subjects (8 active and 2 placebo) planned for evaluation under fasting conditions. One of the planned dose levels will cross over after a washout period to receive the same single dose of XC101-D13H or placebo under fed conditions. Dose escalation will be supervised by a Safety Monitoring Board (SMB). Dose escalation to the next dose level will not take place until the SMB has determined that adequate safety, tolerability, PK, and core-lab analyzed ECGs from the previous cohort and all previous cohorts have been demonstrated to permit proceeding to the next cohort. PK data from all available cohorts will be used to guide the dose-escalation decisions.

Major Inclusion Criteria:

• Healthy, adult, male or female of non childbearing potential only, 18-55 years of age, inclusive, at screening.
• Body mass index (BMI) ≥ 18 and ≤ 30.0 kg/m2 at screening.
• Medically healthy with no clinically significant finding in medical history, physical examination, laboratory profiles, vital signs, or ECGs, as judged by the PI or designee. Creatinine must be within the upper limit of normal at screening.
• Understands the study procedures in the informed consent form (ICF), and is willing and able to comply with the protocol.

Major Exclusion Criteria:

• Is mentally or legally incapacitated or has significant emotional problems at the time of the screening visit or expected during the conduct of the study.
• History or presence of clinically significant medical, surgical, clinical laboratory, or psychiatric condition or disease.
• History of any illness that, in the opinion of the PI or designee, might confound the results of the study or poses an additional risk to the subject by their participation in the study.
• History of clinically significant hypotension.
• History of lightheadedness, dizziness or syncope in the 12 months prior to screening.

Double-blind