A Randomized Controlled Study of Dose-tapering Regimen of Semaglutide for Weight-Loss Maintenance in Adults With Overweight or Obesity

Inclusion Criteria: * Men and women, aged 18 to 64 years inclusive at the time of signing the informed consent form. * Ongoing weight-loss treatment consisting of weekly semaglutide, with a documented weight reduction of ≥ 10% of pre-treatment body weight, or a weight reduction between 5% and \< 10% concurrent with a BMI \< 25 kg/m². * Maintained on a weekly semaglutide dose of 1.7 mg, with a stable weight over the 12 weeks prior to enrollment (less than 5% change in body weight). * Voluntarily participating in the study, capable of effective communication with the investigators, willing to comply with all study procedures, and having provided written informed consent. Exclusion Criteria: * History or planned bariatric surgery or use of a weight-loss device during the trial. * Obesity induced by other endocrinologic disorders or monogenic mutations, including but not limited to hypothalamic obesity, pituitary obesity, hypothyroidism, Cushing's syndrome, insulinoma, acromegaly, or hypogonadism. * Glycated hemoglobin (HbA1c) ≥ 6.5% as measured by a local laboratory at screening, or a history of diabetes mellitus (excluding a history of gestational diabetes). * Use of any weight-loss medications (e.g., tirzepatide, mazdutide, liraglutide, orlistat, sibutramine, phenylpropanolamine, chlorpheniramine, phentermine, lorcaserin, phendimetrazine, phentermine-topiramate, or naltrexone-bupropion), herbal medicines, dietary supplements, or meal replacements affecting body weight within 90 days prior to screening (except semaglutide and lifestyle interventions). Use of medications that may cause significant weight gain, including systemic glucocorticoids for more than 1 week, antipsychotics or antiepileptics (e.g., imipramine, amitriptyline, mirtazapine, paroxetine, phenelzine, chlorpromazine, clozapine, olanzapine, valproic acid and its derivatives, lithium preparations, thioridazine), or growth hormone. * History of acute or chronic pancreatitis, or presence of high-risk factors such as a history of pancreatic injury. Current or past history of malignancies (except for localized basal cell carcinoma of the skin, carcinoma in situ of the cervix, or carcinoma in situ of the prostate). Personal or family history of medullary thyroid carcinoma (MTC) or multiple endocrine neoplasia syndrome type 2 (MEN 2, including MEN 2A and MEN 2B). * End-stage renal disease, or requiring long-term/intermittent hemodialysis or peritoneal dialysis. * Occurrence of any of the following within 60 days prior to screening: myocardial infarction, stroke, hospitalization for unstable angina, or transient ischemic attack (TIA). * Current New York Heart Association (NYHA) class IV heart failure. * Known or suspected hypersensitivity to the investigational product or related products. * Participation in another clinical trial within 90 days prior to screening. * Female patients who are pregnant, breastfeeding, or planning to become pregnant within the next two years. * History of major depressive disorder or a diagnosis of other severe psychiatric disorders (e.g., schizophrenia, bipolar disorder) within 2 years prior to screening. * History of attempted suicide. * Abnormal laboratory results at screening: severe hepatic or renal impairment, such as aspartate aminotransferase (AST) or alanine aminotransferase (ALT) \> 2.5 × upper limit of normal (ULN); bilirubin \> 2.5 × ULN (except for known Gilbert's syndrome meeting the criteria of fractionated conjugated bilirubin \< 35% of total bilirubin); triglycerides ≥ 5.7 mmol/L. * Unstable proliferative retinopathy or maculopathy requiring urgent treatment within 1 year prior to screening, or a history of diabetic ketoacidosis, diabetic hyperosmolar nonketotic coma, or severe metabolic disorders leading to neurological or psychiatric dysfunction. * History or risk factors of the following: clinically significant anemia, epilepsy, syncope, cardiac arrest, arrhythmia, atrioventricular block, structural heart disease, or torsades de pointes. * Severe active bacterial, viral, or fungal infections requiring hospitalization or intravenous antibiotic therapy. * History of infectious diseases, including but not limited to HIV/AIDS, syphilis, or active infectious hepatitis. * History of alcohol dependence or substance abuse within 6 months prior to screening. * Any other condition that, in the opinion of the investigator, makes the patient unsuitable for participation in the study.