To Investigate the Efficacy and Safety of Individualized Doses of BioChaperone Insulin Lispro in Comparison to Humalog® U-100 in Patients With Type 1 Diabetes Mellitus

Inclusion Criteria: * Type 1 diabetes mellitus (as diagnosed clinically) ≥ 12 months * Treated with multiple daily insulin injections (no pump users) ≥ 12 months * Current total daily insulin treatment \<1.2 (I)U/kg/day * Body mass index (BMI) 18.5-28.0 kg/m² (both inclusive) * HbA1c (N-(1-deoxy)-fructosyl-haemoglobin) ≤ 9.0% by local laboratory analysis * Fasting C-peptide ≤ 0.30 nmol/L Exclusion Criteria: * Known or suspected hypersensitivity to trial products or related products * Type 2 diabetes mellitus * Patients using continuous subcutaneous insulin infusion (CSII) * Previous participation in this trial. Participation is defined as randomised * The receipt of any investigational product within 3 months prior to this trial * Clinically significant abnormal haematology, biochemistry, lipids, or urinalysis screening tests, as judged by the Investigator considering the underlying disease * Presence of clinically significant acute gastrointestinal symptoms (e.g. nausea, vomiting, heartburn or diarrhoea), as judged by the Investigator * Known slowing of gastric emptying and or gastrointestinal surgery that in the opinion of the investigator might change gastrointestinal motility and food absorption * Unusual meal habits and special diet requirements or unwillingness to eat the food provided in the trial