| E.1 Medical condition or disease under investigation | 
| E.1.1 | Medical condition(s) being investigated |  | 
| MedDRA Classification | 
| E.1.2 Medical condition or disease under investigation | 
| 
| E.1.2 | Version | 9.1 |  
| E.1.2 | Level | LLT |  
| E.1.2 | Classification code | 10012601 |  
| E.1.2 | Term | Diabetes mellitus |  | 
| E.1.3 | Condition being studied is a rare disease | No | 
| E.2 Objective of the trial | 
| E.2.1 | Main objective of the trial | 
| Primary objective  To assess and compare the efficacy (as assessed by change from baseline in HbA1c) after 26 weeks  of adding liraglutide versus sitagliptin to the pre-trial metformin treatment in subjects with type 2  diabetes inadequately controlled on metformin. |  | 
| E.2.2 | Secondary objectives of the trial | 
| Secondary objectives  To assess and compare the effect on:   other parameters of glycaemic control   ß-cell function (incl. using homeostasis model assessment (HOMA)17)   fasting lipid profile   cardiovascular biomarkers   body weight   waist circumference and waist to hip ratio   blood pressure  In a subset of subjects: PRO assessed by DTSQ  Safety objectives  To assess and compare:   incidence of hypoglycaemic episodes   clinical and laboratory safety parameters |  | 
| E.2.3 | Trial contains a sub-study | No | 
| E.3 | Principal inclusion criteria | 
| Inclusion criteria  1. Informed consent obtained before any trial-related activities (trial-related activities are any  procedures that would not have been performed during normal management of the subject)  2. Subjects (male or female) diagnosed with type 2 diabetes  3. Stable metformin monotherapy of ≥1500 mg daily for at least three months prior to screening.  Short-term change of metformin dose in connection with intercurrent illness within three  months prior to enrolment into the trial is allowed, at the discretion of the Investigator  4. HbA1c 7.5-10.0% (both inclusive)  5. Age 18-80 years, both inclusive (or as allowed according to local guidelines for metformin  treatment)  6. BMI  45.0 (weight [kg]/height2 [m2]) |  | 
| E.4 | Principal exclusion criteria | 
| Previous treatment with insulin, GLP-1 receptor agonists (including liraglutide or exenatide) or  DPP-4 inhibitors (except for short-term treatment with insulin in connection with intercurrent  illness at the discretion of the investigator).  2. Treatment with anti-diabetic drugs other than metformin within the last three months prior to the  trial  3. Impaired liver function, defined as ALAT ≥ 2.5 times upper normal limit (one retest analysed at  the central laboratory within a week is permitted with the result of the last sample being the  conclusive)  4. Impaired renal function defined as CrCl < 50mL/min (see section 8.3.4 for definition of  Cockcroft-Gault formula), or as allowed according to local contraindications for metformin use  (one retest analysed at the central laboratory within a week permitted with the result of the last  sample being the conclusive)  5. Known clinically significant active cardiovascular disease, including history of unstable angina,  acute coronary event, other significant cardiac events (including history of arrythmias or  conduction delays on electrocardiogram (ECG)), or cerebral stroke within the past six months,  and/or heart failure (New York Association (NYHA) Class IV (see appendix C), at the  discretion of the Investigator  6. Known proliferative retinopathy or maculopathy requiring acute treatment, as judged by the  Investigator  7. Uncontrolled treated or untreated hypertension (systolic blood pressure ≥ 180 mmHg and/or  diastolic blood pressure ≥ 100 mmHg)  8. Cancer (except basal cell skin cancer or squamous cell skin cancer) or any other clinically  significant disorder, except for conditions associated with type 2 diabetes history, which in the  Investigators opinion could interfere with the results of the trial  9. Recurrent major hypoglycaemia or hypoglycaemic unawareness, as judged by the Investigator  10. Known or suspected allergy to trial product(s) or related products  11. Use of any drug (except for metformin), which in the Investigators opinion could interfere with  the glucose level (e.g. systemic corticosteroids)12. Receipt of any other anti-diabetic investigational drug within three months or receipt of any  investigational drug not affecting blood glucose within one month prior to screening into this  trial  13. Any contraindications or other restrictions to metformin (incl. known acute or chronic acidosis  or planned use of radio-contrast agents containing iodine) or sitagliptin according to the local  labelling  14. Surgery scheduled for the trial duration period (excluding minor surgical procedures performed  in local anaesthesia, as judged by the Investigator)  15. Previous participation in the randomised phase of this trial. Re-screening is allowed once within  the limits of the recruitment period  16. Known or suspected abuse of alcohol or narcotics  17. Females of childbearing potential who are pregnant, breast-feeding or intend to become  pregnant or are not using adequate contraceptive methods (adequate contraceptive measures as  required by local law or practice  18. Mental incapacity, unwillingness or language barrier precluding adequate understanding or  cooperation |  | 
| E.5 End points | 
| E.5.1 | Primary end point(s) | 
| Primary efficacy endpoint   HbA1c |  | 
| E.6 and E.7 Scope of the trial | 
| E.6 | Scope of the trial | 
| E.6.1 | Diagnosis | No | 
| E.6.2 | Prophylaxis | No | 
| E.6.3 | Therapy | No | 
| E.6.4 | Safety | Yes | 
| E.6.5 | Efficacy | Yes | 
| E.6.6 | Pharmacokinetic | No | 
| E.6.7 | Pharmacodynamic | No | 
| E.6.8 | Bioequivalence | No | 
| E.6.9 | Dose response | No | 
| E.6.10 | Pharmacogenetic | No | 
| E.6.11 | Pharmacogenomic | No | 
| E.6.12 | Pharmacoeconomic | No | 
| E.6.13 | Others | No | 
| E.7 | Trial type and phase | 
| E.7.1 | Human pharmacology (Phase I) | No | 
| E.7.1.1 | First administration to humans | No | 
| E.7.1.2 | Bioequivalence study | No | 
| E.7.1.3 | Other | No | 
| E.7.1.3.1 | Other trial type description |  | 
| E.7.2 | Therapeutic exploratory (Phase II) | No | 
| E.7.3 | Therapeutic confirmatory (Phase III) | Yes | 
| E.7.4 | Therapeutic use (Phase IV) | No | 
| E.8 Design of the trial | 
| E.8.1 | Controlled | Yes | 
| E.8.1.1 | Randomised | Yes | 
| E.8.1.2 | Open | Yes | 
| E.8.1.3 | Single blind | No | 
| E.8.1.4 | Double blind | No | 
| E.8.1.5 | Parallel group | Yes | 
| E.8.1.6 | Cross over | No | 
| E.8.1.7 | Other | No | 
| E.8.2 | Comparator of controlled trial | 
| E.8.2.1 | Other medicinal product(s) | Yes | 
| E.8.2.2 | Placebo | No | 
| E.8.2.3 | Other | No | 
| E.8.3 | The trial involves single site in the Member State concerned | No | 
| E.8.4 | The trial involves multiple sites in the Member State concerned | Yes | 
| E.8.4.1 | Number of sites anticipated in Member State concerned | 9 | 
| E.8.5 | The trial involves multiple Member States | Yes | 
| E.8.6 Trial involving sites outside the EEA | 
| E.8.6.1 | Trial being conducted both within and outside the EEA | Yes | 
| E.8.6.2 | Trial being conducted completely outside of the EEA | Information not present in EudraCT | 
| E.8.6.3 | If E.8.6.1 or E.8.6.2 are Yes, specify the regions in which trial sites are planned |  | 
| E.8.7 | Trial has a data monitoring committee | No | 
| E.8.8 | Definition of the end of the trial and justification where it is not the last
                        visit of the last subject undergoing the trial |  | 
| E.8.9 Initial estimate of the duration of the trial | 
| E.8.9.1 | In the Member State concerned years | 0 | 
| E.8.9.1 | In the Member State concerned months | 11 | 
| E.8.9.1 | In the Member State concerned days |  | 
| E.8.9.2 | In all countries concerned by the trial years | 0 | 
| E.8.9.2 | In all countries concerned by the trial months | 11 |