Dose-ranging Study to Evaluate the Efficacy, Safety, and Tolerability of AMG 133 in Adult Subjects With Overweight or Obesity, With or Without Type 2 Diabetes Mellitus

Inclusion Criteria: * Age ≥18 years at the time of signing informed consent. * BMI ≥30 kg/m\^2, or ≥27 kg/m\^2 and previous diagnosis with at least one of the following comorbidities: hypertension, dyslipidemia, obstructive sleep apnea, cardiovascular disease. * For participants in cohort B only, HbA1c ≥ 7% and ≤ 10% (53 to 86 mmol/mol) at screening with an established diagnosis of type 2 diabetes mellitus for ≥ 180 days prior to screening and either treated with diet and exercise alone or on stable (at least 90 days prior to screening) treatment with metformin, a sulfonylurea, or a sodium-glucose cotransporter 2 (SGLT2) inhibitor as monotherapy or combination therapy, per approved local label. * History of at least one unsuccessful dietary effort to lose body weight. Exclusion Criteria: * Change in body weight greater than 5 kg within 3 months prior to screening. * Obesity induced by other endocrinologic disorders. * History of pancreatitis. * Family or personal history of medullary thyroid carcinoma or multiple endocrine neoplasia syndrome type 2 (MEN-2). * History of major depressive disorder within the last 2 years. * Any lifetime history of other major psychiatric disorder or suicide attempt.