Eligibility Criteria:
Inclusion Criteria:
1. Informed consent obtained before any trial-related activities. Trial-related activities are any procedures that are carried out as part of the trial, including activities to determine suitability for the trial
2. Type 1 diabetes mellitus as diagnosed (including I - III):
I. history of type 1 diabetes mellitus manifestation with acute hyperglycaemia and ketonuria II. positive results for at least one of four islet antibodies (glutamic acid decarboxylase, protein tyrosine phosphatase, zinc transporter 8, or islet cell antibodies) III. residual basal fasting C-peptide of ≥ 0.1 nmol/L
3. Male or female, aged 18 - 64 years (both inclusive)
4. Body mass index (BMI) 20.0 - 25.0 kg/m2 (both inclusive)
5. HbA1c 42 - 80 mmol/mol (6.0-9.5%)
6. Treated with daily insulin injections or continuous s.c. insulin infusion (CSII) ≥ 1 months. Stable insulin dose as judged by the investigator
Exclusion Criteria:
1. Known or suspected hypersensitivity to trial product(s) or related products
2. Use of liraglutide or exenatide within 3 months before screening
3. Severe hypoglycaemia within 1 month of screening
4. Hypoglycaemia unawareness as judged by the Investigator or hospitalisation for diabetic ketoacidosis during the previous 2 months
5. Clinically significant abnormal haematology, biochemistry, lipids, or urinalysis or coagulation screening tests, as judged by the investigator and any of the following laboratory safety results:
* Aspartate transaminase(=AST), alanine aminotransferase (=ALT), lipase, alkaline phosphatase \> 2.0 times upper limit of reference range (ULN)
* Haemoglobin \< 8.0 mmol/L (male) or \< 6.4 mmol/L (female), total leukocyte count \<3.0 x 109/L, thrombocytes \<100 x 109/L
* Serum creatinine levels ≥ 126 μmol/L (male) or ≥ 111 μmol/L (female)
* Amylase outside normal range
6. Screening calcitonin \> 50 ng/L
7. Personal history of non-familial medullary thyroid carcinoma
8. History of chronic or idiopathic acute pancreatitis Suffer from or history of a life threatening disease (e.g. cancer except basal cell skin cancer or squamous cell skin cancer), or any clinically significant respiratory, metabolic, renal, hepatic, gastrointestinal, endocrinological (with the exception of diabetes mellitus and euthyroid struma), haematological, dermatological, venereal, neurological, psychiatric diseases or other major disorders as judged by the investigator.
9. Proliferative retinopathy or maculopathy and/or severe neuropathy, in particular autonomic neuropathy, as judged by the investigator.
10. Any disease or condition that, in the opinion of the investigator, would represent an unacceptable risk for the subject's safety.
11. Any condition that would interfere with trial participation or evaluation of results, as judged by the investigator.
12. Female of child-bearing potential who is pregnant, breast-feeding or intend to become pregnant or is not using adequate contraceptive methods (adequate contraceptive methods include sterilisation, hormonal intrauterine devices, oral contraceptives, sexual abstinence or vasectomised partner).
13. Severe acute and/or chronic diseases