Study to Compare the Efficacy and Safety of Administration of the Fix Dose Combination of Linagliptin Plus Metformin in Drug naïve Type 2 Patients

Inclusion criteria: 1. Diagnosis of Type 2 diabetes mellitus(T2DM) prior to informed consent 2. Male and female patients on diet and exercise regimen who are drug-naïve 3. Glycosylated haemoglobin A1c (HbA1c) at V1a \>/=7.5 %\<11% for main group and HbA1c \>/= 11.0 % for the additional parallel group 4. Age \>/= 18 and \</= 80 years at Visit 1a (Screening) 5. Body Mass Index(BMI)\</ = 40 kg/m2 at Visit 1a (Screening) 6. Signed and dated written informed consent by date of Visit 1a in accordance with good clinical practice(GCP) and local legislation Exclusion criteria: 1. Uncontrolled hyperglycaemia required for rescue medication during placebo run-in phase 2. In main group, the patients with investigational medicinal product(IMP) compliance \< 80 % or \>120 % during 2 weeks placebo run in period 3. Acute coronary syndrome stroke or Transient ischaemic attack (TIA) within 3 months prior to randomisation 4. Impaired hepatic function, defined by serum levels of either Alanine aminotransferase(ALT) ,Aspartate aminotransferase(AST), or alkaline phosphatase (AP) above 3 x upper limit of normal (ULN) ,or total bilirubin above 1.5 x ULN as determined at Visit 1a 5. Known hypersensitivity or allergy to linagliptin or its excipients or metformin or placebo 6. Treatment with anti-obesity drugs 3 months prior to informed consent or any other treatment at the time of screening 7. Alcohol or drug abuse within the 3 months prior to informed consent that would interfere with trial participation or any ongoing condition leading to a decreased compliance to study procedures or study drug intake in the opinion of the investigator. 8. Concurrent participation in another clinical trial or any investigational therapy within thirty days prior to signing the consent form or during the trial. 9. Pre-menopausal women (last menstruation \</= 1 year prior to informed consent) who are nursing or pregnant or are of child-bearing potential and are not practicing an acceptable method of birth control, or do not plan to continue using this method throughout the study 10. Current treatment with systemic steroids at time of informed consent or change in dosage of thyroid hormones within 6 weeks prior to informed consent. 11. Renal failure or renal impairment at Visit 1a (screening) with an Estimated Glomerular Filtration Rate(eGFR) \< 60 ml/min 12. Bariatric surgery within the past two years and other gastrointestinal surgeries that induce chronic malabsorption 13. Dehydration by clinical judgement of the investigator 14. Clinical detected unstable or acute congestive heart failure 15. Acute or chronic metabolic acidosis (present in patient history) 16. Hereditary galactose intolerance 17. Known history of pancreatitis and chronic pancreatitis 18. Medical history of cancer (except for basal cell carcinoma) and/or treatment for cancer within last 5 years. 19. Any other clinical condition that would jeopardize patients safety while participating in this clinical trial at the discretion of investigator