Efficacy and Safety of Linagliptin (BI 1356) in Black/African Americans With Type 2 Diabetes With a MTT Sub-study

Inclusion criteria: 1. Dated written informed consent that is in accordance with GCP and local legislation. 2. Male and female Black / African American patients 3. Diagnosis of type 2 diabetes at least 3 months prior to the informed consent. 4. HbA1c more than or equal to 7.5% and less than or equal to 11% at Visit 1. 5. Patients are currently treatment-naive or being treated with up to one oral antidiabetic medication. Antidiabetic medication is to be unchanged for at least 10 weeks prior to the informed consent. 6. Age more than 18 and less than 80 years at Visit 1 (Screening). 7. BMI (Body Mass Index) less than 45 kg/m2 at Visit 1. Exclusion criteria: 1. Myocardial infarction (MI), stroke or transient ischemic attack (TIA) within 3 months of informed consent. 2. Type 1 diabetes. 3. Impaired hepatic function, defined by serum levels of either alanine aminotransferase (ALT, SGPT), aspartate aminotransferase (AST, SGOT), or alkaline phosphatase above 3 x upper limit of normal (ULN) as determined at Visit 1. 4. Known prior hypersensitivity or allergy to the investigational product or its excipients. 5. Treatment with insulin within 3 months prior to informed consent. 6. Treatment with anti-obesity drugs (e.g., sibutramine, orlistat, rimonabant) within three months prior to informed consent or initiating therapy during the study. 7. Any prior use of dipeptidyl peptidase-4 (DPP-4) inhibitors. 8. Glucagon-like peptide-1 (GLP-1) agonists are excluded 3 months prior to informed consent. 9. History of alcohol or drug abuse within 3 months prior to informed consent that would interfere with trial participation as assessed by the Investigator. 10. Participation in another trial with an investigational drug within 3 months prior to informed consent or during the study. 11. Pre-menopausal women (last menstruation less than 1 year prior to informed consent) who: * are nursing or pregnant * are not surgically sterile * 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 and do not agree to submit to periodic pregnancy testing during participation in the trial. Acceptable methods of birth control include transdermal patch, intrauterine devices/systems (IUDs / IUSs), oral, implantable or injectable contraceptives, and vasectomised partners. No exceptions will be made. Hormonal birth control should have been in use for at least three months prior to signing informed consent and continue at least until the next menstrual period after completing the study. 12. Current treatment with chronic use of systemic steroids at time of informed consent or change in dosage of thyroid hormones within 6 weeks prior to informed consent. 13. History of bariatric surgery. 14. Patients who have demonstrated an inability to be compliant (80-120%) with the dosing regimen during the placebo run-in period.