Clinical Research Directory

Inclusion Criteria: * 1\. Voluntarily signed informed consent. * 2\. Age 18 to 70 years, inclusive. * 3\. Diagnosed with LADA, defined as meeting all of the following: * (1) Meets 1999 WHO criteria for diabetes mellitus. * (2) Age at diagnosis of diabetes ≥ 18 years. * (3) Positive for at least one islet autoantibody (GADA, IA-2A, or ZnT8A). * (4) Did not require continuous insulin therapy for at least 6 months after diagnosis. * 4\. Stimulated C-peptide ≥ 200 pmol/L. * 5\. Glycated Hemoglobin (HbA1c) ≤ 9.0%. * 6\. For women of childbearing potential, must agree to use a highly effective method of contraception throughout the study. Exclusion Criteria: * 1\. Pregnant, breastfeeding, or planning to become pregnant during the study. * 2\. Gestational diabetes or other specific types of diabetes. * 3\. Known hypersensitivity to Cogliptin, Vitamin D3, or their excipients. * 4\. Use of DPP-4 inhibitors, GLP-1 receptor agonists, or thiazolidinediones (TZDs) within 8 weeks prior to randomization. * 5\. Hypercalcemia (serum calcium above the upper limit of the normal range). * 6\. Systemic corticosteroid therapy (oral or IV) for more than 7 consecutive days within 6 months prior to screening. * 7\. Alanine aminotransferase (ALT) or aspartate aminotransferase (AST) \> 3 times the upper limit of normal (ULN), or total bilirubin \> 2 times ULN. * 8\. Estimated glomerular filtration rate (eGFR) \< 45 mL/min/1.73 m². * 9\. History of acute diabetic complications such as diabetic ketoacidosis (DKA) or hyperosmolar hyperglycemic state. * 10\. History of pancreatitis or pancreatic surgery. * 11\. New York Heart Association (NYHA) class III or IV congestive heart failure, or known left ventricular ejection fraction (LVEF) \< 40%. * 12\. History of malignancy. * 13\. Severe psychiatric illness. * 14\. History of alcohol or illicit drug dependence. * 15\. Any other severe systemic disease that the investigator deems unsuitable for enrollment.