Efficacy and Safety of KAI-9531 Administered Once Weekly in Participants Living With Obesity Who Do Not Have Diabetes

The primary objective of this study is to determine the effects of KAI-9531 administered by subcutaneous (SC) injection once weekly compared to placebo on percent change in body weight.

Key Inclusion Criteria: * BMI ≥35 kilograms per meter squared (kg/m\^2). * History of at least 1 self-reported unsuccessful effort to lose weight with diet and exercise within the prior 6 months. Key Exclusion Criteria: * Current diagnosis or history of diabetes mellitus, including type 1 diabetes mellitus (T1DM) or type 2 diabetes mellitus (T2DM), history of diabetic ketoacidosis, or hyperosmolar state/coma. * Started medications within 3 months prior to Screening that may cause significant weight gain, including, but not limited to, tricyclic antidepressants, atypical antipsychotics, and mood stabilizers. * Unstable weight defined as self-reported change in body weight exceeding 5% within 3 months prior to Screening. * Family or personal history of multiple endocrine neoplasia Type 2 or medullary thyroid cancer. * Uncontrolled hypertension or unstable cardiovascular disease. * History of chronic or acute pancreatitis. * Known clinically significant gastric-emptying abnormality or chronic treatment with medications that directly affect gastrointestinal motility. * History of suicide attempt. * History of significant active or unstable Major Depressive Disorder (MDD) or other severe psychiatric disorder within 2 years prior to Screening. * Received treatment with semaglutide, tirzepatide, glucagon-like peptide-1 receptor (GLP-1R) agonist, GLP-1R/glucose-dependent insulinotropic polypeptide receptor (GIPR), or glucagon receptor agonist within 3 months prior to Screening. Note: Additional inclusion/exclusion criteria may apply, per protocol.