A Research Study to Compare Two Types of Insulin, a New Weekly Insulin, Insulin Icodec and an Available Daily Insulin, Insulin Glargine, Both in Combination With Mealtime Insulin, in People With Type 2 Diabetes Who Use Daily Insulin and Mealtime Insulin (ONWARDS 4)

Inclusion Criteria

• •Male or female aged above or equal to 18 years at the time of signing informed consent.
• •Diagnosed with type 2 diabetes mellitus (T2D) greater than or equal to 180 days prior to the day of screening.
• •Glycated haemoglobin (HbA1c) from 7.0-10.0% (53.0 85.8 mmol/mol) both inclusive at screening confirmed by central laboratory analysis.
• •Treated with once daily basal insulin (neutral protamine hagedorn insulin, insulin degludec, insulin detemir, insulin glargine 100 units/mL, or insulin glargine 300 units/mL) and 2-4 daily injections of bolus insulin analog (insulin aspart, faster acting insulin aspart, insulin lispro, insulin glulisine) greater than or equal to 90 days prior to the day of screening with or without any of the following anti-diabetic drugs/regimens with stable doses greater than or equal to 90 days prior to screening:
• •Metformin / Sulfonylureas / Meglitinides (glinides) / DPP-4 inhibitors / SGLT2 inhibitors / Thiazolidinediones / Alpha-glucosidase inhibitors / Oral combination products (for the allowed individual oral anti-diabetic drugs) / Oral or injectable GLP-1-receptor agonists
• •Body mass index (BMI) below or equal to 40.0 kg/m\^2.