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 resectednonmelanoma 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 ornon-feasible