Efficacy and Safety of Empagliflozin (BI 10773) Versus Placebo and Sitagliptin Over 24 Weeks in Patients With Type 2 Diabetes

Inclusion criteria: 1. Diagnosis of type 2 diabetes mellitus prior to informed consent; 2. Male and female patients on diet and exercise regimen who are drug-naïve; 3. HbA1c \>= 7.0% and \<= 10.0% at Visit 1 (screening) for randomised treatment; HbA1c \> 10.0% at visit 1 (screening) for the open-label BI 10773 arm; 4. Age \>= 20 (Japan); Age \>= 18 (countries other than Japan); 5. BMI \<= 45 kg/m2 at Visit 1 (screening); 6. Signed and dated written informed consent by date of Visit 1 Exclusion criteria: 1. Uncontrolled hyperglycaemia; 2. Acute coronary syndrome (non-STEMI, STEMI and unstable angina pectoris), stroke or TIA within 3 months prior to informed consent; 3. Indication of liver disease, either ALT, AST, or alkaline phosphatase above 3 x ULN; 4. Impaired renal function (eGFR\<50 ml/min); 5. Bariatric surgery within the past two years or other GI surgeries; 6. Medical history of cancer; 7. Contraindications to sitagliptin; 8. Blood dyscrasias or any disorders causing haemolysis or unstable red blood cell; 9. Treatment with any anti-diabetes drug within 12 weeks prior to randomisation; 10. Treatment with anti-obesity drugs or any other treatment leading to unstable body weight; 11. Current treatment with systemic steroids or change in dosage of thyroid hormones within 6 weeks prior to informed consent or any other uncontrolled endocrine disorder except T2DM; 12. Pre-menopausal women who are nursing or pregnant or are of child-bearing potential and not practicing an acceptable method of birth control; 13. Alcohol or drug abuse; 14. Intake of an investigational drug in another trial within 30 days prior to intake of study medication in this trial; 15. Any other clinical condition that would jeopardize patients safety while participating in this clinical trial