A Trial to Assess Bioavailability of AMG 133 in Participants With Overweight or Obesity

Inclusion criteria

• Provide signed and dated informed consent before any study procedures.
• Be male or female, 18 to 65 years old, at screening.
• May have well-controlled conditions such as obstructive sleep apnea, high blood pressure, high cholesterol, or hypothyroidism on stable treatment for ≥ 3 months. Other mild, stable health conditions may be allowed with investigator and medical monitor approval.
• Body mass index (BMI) between 25 and 40 kg/m² at screening.
• Stable body weight (less than 5 kg change by self-report) during the 3 months before screening.
• No major changes in diet or lifestyle (such as new weight-loss or exercise programs) during the past 3 months.

Exclusion criteria

• Any significant medical condition or abnormal test result that could increase risk or interfere with study participation, based on investigator judgment.
• Diabetes (any type except past gestational diabetes) or Hemoglobin A1c (HbA1c) ≥ 6.5%.
• Endocrine disorders that can cause obesity (for example, Cushing's syndrome).
• Pancreatitis within the past year, or abnormal pancreatic blood tests (lipase/amylase > 2 × normal) or fasting triglycerides > 500 mg/dL.
• Cancer within 5 years (except treated non-melanoma skin cancer or in-situ cervical/breast lesions).
• Personal or family history of medullary thyroid carcinoma or multiple endocrine neoplasia type 2.
• Uncontrolled thyroid disease (thyroid stimulating hormone [TSH] > 6.0 or < 0.4 mIU/L). Participants on stable thyroid-replacement therapy for ≥ 3 months may be included if TSH is in range.
• History or current signs of gastroparesis (delayed stomach emptying).
• Weight-loss surgery within 6 months before check-in.
• Heart or blood-vessel disease (aside from controlled high blood pressure or cholesterol), such as heart attack, angina, valve disease, or prior bypass/stent.
• Clinically significant abnormal heart rhythm on electrocardiogram (ECG) at screening or check-in.
• QT corrected for heart rate using Fridericia's method (QTcF) > 450 ms (males) or > 470 ms (females), or a history of long QT syndrome.
• Second- or third-degree heart block.
• Blood pressure > 150/95 mmHg or < 90/50 mmHg, or pulse > 110 bpm. A single repeat is allowed if values normalize.
• Allergy or hypersensitivity to AMG 133 or its ingredients.
• Poor veins for blood draws.
• Kidney function (estimated glomerular filtration rate [eGFR]) ≤ 60 mL/min/1.73 m^2.
• Liver enzymes (alanine aminotransferase [ALT] or aspartate aminotransferase [AST]) > 2X normal.
• Positive test for hepatitis B, hepatitis C, or human immunodeficiency virus (HIV) (exceptions apply for prior vaccination or resolved hepatitis B virus [HBV] infection).
• Current or recent (within 6 months) suicidal thoughts, suicide attempts, or major psychiatric illness, including depression.
• Use of any prescription or over-the-counter medicines within 30 days or 5 half-lives (whichever is longer) before check-in, except:

• Acetaminophen ≤ 2 g/day for pain
• Hormone replacement (e.g., estrogen, thyroid) or hormonal contraception
• Stable treatments (≥ 3 months) for high blood pressure, high cholesterol, or other mild, well-controlled conditions approved by the investigator and medical monitor.
• Use of any glucagon-like peptide-1 (GLP-1) or glucose-dependent insulinotropic polypeptide (GIP) receptor agonist/antagonist within 3 months.
• Use of herbal medicines, vitamins, or supplements within 30 days, unless approved by the investigator and sponsor.
• Consumption of poppy-seed-containing foods within 7 days before check-in.
• Alcohol abuse or regular intake > 21 units/week (men) or > 14 units/week (women), or drug abuse within 1 year. (1 unit = 12 oz beer, 1.5 oz liquor, 5 oz wine.)
• Alcohol use within 48 hours before check-in, or unwillingness to limit alcohol to ≤ 1 unit/day from discharge through study end.
• Strenuous exercise or a new exercise program within 7 days before check-in.
• Positive drug screen or tetrahydrocannabinol (THC) test, or unwillingness to avoid illicit drugs/THC through end of study.
• Positive pregnancy test at screening or check-in.
• Breastfeeding, or planning to breastfeed within 16 weeks after receiving AMG 133.
• Men and women unwilling to use required contraception through 16 weeks after receiving AMG 133.
• Men unwilling to abstain from sperm donation or women unwilling to abstain from egg donation through 16 weeks after receiving AMG 133.
• Men with female partners of childbearing potential unwilling to inform their partner and adhere to contraception requirements.
• Men with pregnant partners (or partners planning pregnancy) unwilling to use effective contraception or abstain from intercourse through 16 weeks after receiving AMG 133.
• Participation in another investigational drug study within 30 days or 5 half-lives (whichever is longer).
• Previous participation in any study of AMG 133.
• Blood donation within 3 months, plasma within 2 weeks, or platelets within 6 weeks before check-in.
• Unwillingness to follow study requirements or restrictions.
• Any other reason, in the investigator's opinion, that makes participation unsuitable.