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

After a screening visit, eligible subjects will enter a run-in period. Subjects will receive a Continuous Glucose Monitoring (CGM) system for glucose monitoring and control at the beginning of the run-in and for the whole duration of the study. Each eligible subject will then be randomly allocated to a sequence of the 2 treatments, i.e. multiple daily injections of ADO09 and insulin aspart during 2 dosing periods. At Day 1 a mixed meal test (MMT) will be conducted at breakfast and subjects will remain at the clinical site until day 3. At Day 3 subjects will leave the clinical site and continue the treatment with IMP for the next 3 weeks. On Day 23 subjects will come back for a MMT on Day 24. This study is constituted of 2 parts. In the first part (Part A), only subjects with daily prandial insulin dose ≤ 40 U/day will be enrolled. Following the completion of the part A, an extension part (Part B) will be conducted to particularly assess the safety and tolerability of higher daily doses of ADO09 in patients with insulin requirements ≥ 40 U/day. The clinical conduct and procedures will not change for the Extension Part of the study.