1. Ability and willingness to participate in the study, give written informed consent, and comply with the study restrictions and all protocol procedures

2. Sex: male or female

3. Weight: >50 kg, inclusive, at screening

4. Age:

1. For Part A 18 to 70 years, inclusive, at screening

2. For Part B, Part B-EXT, and C 18 to 55 years, inclusive, at screening

5. Body Mass Index

1. For Part A: ≥18.5 kg/m2 and ≤35.0 kg/m2, inclusive, at screening

2. For Part B and Part B-EXT: ≥30.0 kg/m2 and ≤40.0 kg/m2, inclusive, at screening

3. For Part C: ≥25.0 kg/m2 and ≤40.0 kg/m2, inclusive, at screening

6. Patients with T2DM for at least 6 months, having HbA1c of 6.5% to 8.5% (Part C)

Key Exclusion Criteria:

1. History or clinically significant active disease of the gastrointestinal, cardiovascular, hepatic, neurologic, renal, pancreatic, immunologic, dermatologic, endocrine, genitourinary, or hematologic system

2. Uncontrolled hypertension

3. History of type 1 diabetes mellitus

4. History or current diagnosis of acute or chronic pancreatitis or factors for pancreatitis

5. Personal or family history of medullary thyroid carcinoma or multiple endocrine neoplasia syndrome type 2 or subjects with suspected medullary thyroid carcinoma

6. Existence of any surgical or medical condition that, in the judgment of the Investigator, might interfere with the absorption, distribution, metabolism, or excretion of the investigational product