UBT251 Injection Phase Ⅲ Study (Overweight or Obesity)

Inclusion Criteria： 1. Age 18-75 years (inclusive) at the time of signing the informed consent form, regardless of gender; 2. Body mass index (BMI) ≥28.0 kg/m² (obesity) or 24.0 kg/m² ≤ BMI \<28.0 kg/m² (overweight) at screening, accompanied by by at least one of the following: a. Prediabetes, hypertension, dyslipidemia, or fatty liver; b. Weight-bearing joint pain; c. Obesity-induced dyspnea or obstructive sleep apnea syndrome; 3. Self-reported having been on diet and exercise control for 3 months or more prior to screening, with body weight change ≤5 kg within the past 3 months; 4. Trial participants (including their partners) have no plan for pregnancy from screening to 6 months after trial completion, and are willing to comply with the contraceptive measures specified in the trial, and have no plan for sperm or egg donation within 6 months after trial completion; 5. Have been fully informed about this study and voluntarily sign a written informed consent form. Exclusion Criteria: 1. Known history of hypersensitivity to this study drug, its drug product excipients, or other similar active drugs; 2. Any of the following medication history within 3 months before randomization: 1. Treatment with dipeptidyl peptidase-4 (DPP-4) inhibitors, amylin analogs, glucagon-like peptide-1 (GLP-1) analogs, glucose-dependent insulinotropic polypeptide (GIP) analogs, or glucagon (GCG) analogs; 2. Use of over-the-counter weight-loss medications or appetite suppressants (including traditional Chinese medicine, dietary supplements, meal replacements), or prescription weight-loss medications (including but not limited to orlistat) or lipolytic injections (e.g., fat-dissolving injections); 3. Use of medications that may affect body weight for a duration of 1 week or longer, or anticipated use during the trial, including but not limited to systemic glucocorticoid therapy (intravenous or oral administration, except for the following: topical external use or intra-articular, intranasal, ophthalmic, and inhaled glucocorticoids; short-term \[≤7 days\] systemic glucocorticoid use for prevention or treatment of non-autoimmune allergic diseases, upper respiratory tract infection); 4. Treatment with tricyclic antidepressants, antipsychotics, or antiepileptic medications; 5. Treatment with antidiabetic medications; 3. History or evidence of any of the following diseases: 1. Diagnosis of type 1, type 2 diabetes mellitus, or other types of diabetes mellitus (excluding history of gestational diabetes mellitus); 2. Secondary obesity caused by diseases (including but not limited to elevated cortisol hormones \[e.g., Cushing's syndrome\], pituitary/hypothalamic injury, hypothyroidism, etc.) or medications (including but not limited to long-term glucocorticoid use, antidepressants, etc.); 3. History of acute or chronic pancreatitis, or pancreatic surgery; 4. History of symptomatic gallbladder disease within 1 year before screening (excluding trial participants who have undergone cholecystectomy \[completed at least 3 months before screening\] without long-term complications), or abdominal ultrasound at screening indicating large gallstones (diameter ≥2 cm), gallbladder polyps (diameter ≥1 cm), or other gallbladder lesions that the study physician determines may affect trial participant safety; 5. Personal or family history (within first-degree relatives, i.e., parents, children, or siblings) of medullary thyroid carcinoma (MTC) or multiple endocrine neoplasia type 2 (MEN2); 6. Planned bariatric surgery during the trial or history of bariatric surgery, except for the following: a) acupuncture for weight loss or liposuction (e.g., abdominal liposuction) performed \>1 year before screening; b) gastric banding, but the band was removed \>1 year before screening; c) intragastric balloon, but the balloon was removed \>1 year before screening; d) duodenal-jejunal bypass liner, but the liner was removed \>1 year before screening; 7. History of depression or severe mental illness (including but not limited to suicidal tendencies, schizophrenia, bipolar disorder, etc.); 8. History of clinically significant cardiovascular or cerebrovascular disease within 6 months before screening; 9. Severe retinal or macular disease (including but not limited to proliferative retinopathy, macular edema, retinal detachment, etc.) at screening or in the past, requiring urgent treatment as determined by the study physician; 10. History of malignancy; 4. Blood loss ≥400 mL (including trauma, blood draw, blood donation) within 3 months before screening, or receipt of blood or blood component transfusion; 5. Lactating women or pregnant women;