A 2-part, Phase 1b Clinical Study Designed to Evaluate the Safety, PK, and Efficacy of CRB-913 in Participants With Obesity

Inclusion Criteria: * Part 1: Participants with BMI 18.0-25.0 kg/m² * Part 2: Obese participants with BMI ≥30 kg/m² Exclusion Criteria: * Significant liver disease or moderate-severe hepatic impairment * History of seizures, epilepsy, or intracranial surgery * Diabetes mellitus (Type 1 or Type 2), except gestational * Bariatric surgery or \>5 kg weight change in past 3 months * Recent use (within 3 months) of GLP-1 agonists or other weight-loss medications * Major depression within 2 years. * Any history of suicidal ideation/attempt * Severe psychiatric disorders (e.g., schizophrenia, bipolar disorder) * Elevated screening scores: PHQ-9 \>4, GAD-7 \>4, or positive C-SSRS Items 1-2 * Active or recent (within 5 years) malignancy (exceptions: in situ and fully resected nonmelanoma skin cancer) * Abnormal thyroid function: TSH \>6 mIU/L unless stable on replacement therapy * QTc \>470 msec (females) or \>450 msec (males) or history of long QT syndrome * Use of systemic corticosteroids or unstable chronic medications affecting BP, lipids, or glucose * Use of CYP3A4 substrates or strong P-gp substrates/inhibitors * Investigational drug use within 28 days * Prior exposure to CRB-913 or other CB1 inverse agonists/antagonists * Substance abuse history * Pregnancy, breastfeeding, or unwillingness to use highly effective contraception * Positive drug or alcohol screen * Any condition that, in the investigator's judgment, makes participation unsafe or non-feasible