The purpose of this study is to assess the efficacy of HSK7653 (as an add-on to metformin) compared with linagliptin after 24 weeks, and the safety (up to 52 weeks) of HSK7653 in Chinese patients with Type 2 Diabetes who have inadequate glycemic control on diet/exercise therapy and metformin agent monotherapy.

The treatment period is composed of a 24-week double-blind period (week 1-24) and a 28-week open-label period (week 25-52). During the double-blind period, participants will receive 10 mg or 25 mg dose of HSK7653, or linagliptin, and with matching placebo respectively. During the open-label period, all participants will receive 25 mg dose of HSK7653. All participants will receive a stable dose of metformin therapy in both the double-blind period and the open-label period.

Inclusion Criteria:

• Age ≥ 18 and ≤ 75 years, Male and female patients;
• Type 2 diabetes mellitus;
• Insufficient glycaemic control with diet/exercise therapy and metformin agent monotherapy;
• Did not receive regular long-term medication of oral hypoglycemic drugs (except metformin) or insulin within 1 year prior to informed consent;
• HbA1c in the range of ≥7.5 to ≤11.0% at screening;
• FPG < 15 mmol/L at screening;
• BMI (Body Mass Index) in the range of ≥ 18.0 kg/m² to ≤ 35.0 kg/m² at screening.

Exclusion Criteria:

• Diabetic ketoacidosis, hyperglycemia hypertonic state, serious complications of diabetes, myocardial infarction, stroke within 6 months prior to informed consent;
• History of severe endocrine disease, uncured cancer, acute pancreatitis prior to informed consent;
• Current hemoglobinopathy, uncontrolled hypertension, serious nephropathy or hepatopathy prior to informed consent;
• Serious gastrointestinal disease within 2 weeks prior to informed consent;
• Serious infection, trauma, and surgery within 3 months prior to informed consent;
• History of treatment with Dipeptidyl-Peptidase 4 (DPP-4) inhibitor, Glucose-dependent insulinotropic polypeptide (GIP) or Glucagon-like peptide-1 (GLP-1) receptor agonist;
• Treatment with drugs that affect glucose metabolism within 8 weeks prior to informed consent;
• Hemoglobin (HGB) < 10.0 g/dL(100 g/L);
• Alcohol abuse within 6 months or drug abuse history within 5 years prior to informed consent;
• Active infectious diseases;
• Participation in another trial with an investigational drug or instrument within 3 months prior to informed consent;
• Women who are nursing or pregnant, or subjects who have planned parenthood;
• Contraindication for empagliflozin or linagliptin;
• Other protocol-defined inclusion/exclusion criteria.