This is a first-in-human study to evaluate safety and tolerability, pharmacokinetics, and pharmacodynamics of single and multiple dose levels of KT-579 in healthy male and female adult participants.

Inclusion Criteria:

• Participants with a weight of at least 50 kg if male or 40 kg if female, and a body mass index (BMI) between 18.0 and 32.0 kg/m² (inclusive) at Screening.
• Participants must be willing and able to read, understand, and sign an informed consent form (ICF) which includes compliance with requirements and restrictions listed in the ICF and in this protocol.
• Participants must be willing and able to comply with scheduled visits, treatment plan, laboratory tests, and other study procedures.

Exclusion Criteria:

• Participants who have a clinically relevant history of respiratory, gastrointestinal (GI), renal, hepatic, hematological, lymphatic, endocrinological, neurological, cardiovascular, psychiatric, musculoskeletal, genitourinary, immunological, dermatological, ophthalmological, or connective tissue diseases or disorders.
• Participants who have a clinically relevant surgical history (e.g. surgery of the GI tract that could interfere with the PK of the trial medication) Note: prior appendectomy or cholecystectomy is not exclusionary.
• Participants with a history of alcohol or substance abuse within the previous 2 years.
• Participants who have any known factor, condition, or disease that might interfere with treatment compliance, study conduct or interpretation of the results such as drug or alcohol dependence or psychiatric disease.
• Participants who test positive for alcohol and drugs of abuse at Screening and on admission to the CRU.
• Participants who have acute GI symptoms at the time of Screening or on admission to the CRU (e.g. nausea, vomiting, diarrhea, heartburn).
• Participants whose results from clinical laboratory safety tests are outside the local reference range at Screening and on admission to the CRU.
• Participants who have previously received KT-579 in another cohort in this study.
• Participants who have been dosed with any investigational drug or device in a clinical study within 30 days or 5 half-lives (whichever is longer) of KT-579/placebo administration.
• Male participants who do not agree to refrain from sperm donation from admission to the CRU to 90 days after the last dose of study drug.
• Male participants (and their partners of childbearing potential) and female participants who do not agree to the contraception requirements as specified in the clinical protocol.
• Female participants who are pregnant, lactating, or breast-feeding or plan to become pregnant (including ova donation) within 30 days of last study drug administration.
• Female participants with a positive or undetermined pregnancy test at Screening and on admission to the CRU.

The Sponsor is also masked to treatment allocation.