A Study of Safety of SUN-0864 and How it is Processed by and Affects the Body in Healthy Adults and Healthy Adults Who Are Overweight or Obese.

This Phase 1, first-in-human study will evaluate the safety and tolerability of SUN-0864, how the body processes SUN-0864, and how SUN-0864 affects the body in healthy adults and otherwise healthy adults who are overweight or obese. The study includes four parts: Part 1, a single ascending dose (SAD) assessment in healthy adults; Part 2, a 28-day multiple ascending dose (MAD) assessment in overweight or obese adults; Part 3, a 12-week multiple-dose assessment in overweight or obese adults; and Part 4, an assessment comparing two formulations and evaluating the effect of food on SUN-0864 in healthy adults. Approximately 128 to 138 subjects will be randomized into this study. Dose escalation and selection of dose levels for later study parts will be guided by review of safety, tolerability, and available study data by a Safety Review Committee.

Inclusion Criteria: * Healthy male or female subjects between the ages of 18-64 years. * Part 1 \& 4 Body Mass Index (BMI): 18.0 to 32.0kg/m2; and a total body weight\> 50 kg (110lbs) * Part 2 BMI: ≥ 27.0 kg/m2 and ≤ 40.0 kg/m2 and a body weight ≥ 70 kg and ≤ 150 kg * Part 3 BMI: BMI ≥ 30.0 kg/m2 and a body weight ≥ 70 kg Exclusion Criteria: * Evidence or history of clinically significant hematological, renal, endocrine, pulmonary, respiratory, dermatologic, inflammatory, gastrointestinal, cardiovascular, hepatic, psychiatric, neurologic, or allergic disease. * Any condition possibly affecting drug absorption. * History of recent surgery requiring general anesthesia (within 12 weeks of Screening) * Participants with clinically significant abnormalities for laboratory values or physical examination. * History of major depressive disorder or history of other severe psychiatric disorders or any history of suicidal behavior. * Part 3: any form of diabetes (except gestational diabetes) requiring pharmacologic management and/or on medication to treat hyperglycaemia.