A Trial to Assess Safety and Efficacy of ADO09 Versus Insulin Aspart in Subjects With Type 1 Diabetes Mellitus

Inclusion Criteria: * Signed and dated informed consent obtained before any trial-related activities. * Type 1 diabetes mellitus (as diagnosed clinically) ≥ 12 months. * Treated with insulin ≥ 12 months. * Using a multiple dosing insulin therapy (MDI) with basal and bolus insulin. * HbA1c ≤ 9.0%. * Fasting negative C-peptide (≤ 0.30 nmol/L). * Total daily prandial dose: ≤ 40U in the Part A and ≥ 40 U in the Part B Exclusion Criteria: * Known or suspected hypersensitivity to products used in the clinical trial * Type 2 diabetes mellitus * Previous participation in this trial. Participation is defined as randomized. * Receipt of any medicinal product in clinical development within 3 months before randomization in this trial. * Known slowing of gastric emptying, including gastroparesis, and or gastrointestinal surgery that in the opinion of the investigator might change gastrointestinal motility and food absorption. * Presence of clinically significant acute gastrointestinal symptoms (e.g. nausea, vomiting, heartburn or diarrhoea), as judged by the Investigator. * Intake of medication known to affect gastrointestinal motility, including but not limited to erythromycin, metoclopramide, cisapride, cholestyramine or colestipol within 4 weeks before screening.