A Research Study to See How Switching From a Daily Basal Insulin to a New Weekly Insulin, Insulin Icodec, Helps in Reducing the Blood Sugar Compared to Daily Insulin Glargine in Adults With Type 2 Diabetes

Inclusion Criteria:

• Diagnosed with T2D greater than equal to (≥) 180 days prior to the day of screening.

• HbA1c from 7.0-10.0% (53.0-85.8 mmol/mol), both inclusive, at screening confirmed bycentral laboratory analysis.

• Treated with once-daily or twice-daily basal insulin (Neutral Protamine Hagedorninsulin, insulin degludec, insulin detemir, insulin glargine 100 U/mL, or insulinglargine 300 U/mL) ≥ 90 days prior to the day of screening with or without any ofthe following anti-diabetic drugs/regimens with stable doses greater than equal to (≥) 90 days prior to screening: metformin, sulfonylureas, meglitinides (glinides),Dipeptidyl peptidase 4 (DPP-4) inhibitors, Sodium-Glucose Transport Protein 2 (SGLT2) inhibitors, thiazolidinediones, alphaglucosidase inhibitors, oralcombination products (for the allowed individual oral anti- diabetic drugs), oral orinjectable glucagon-like peptide 1 receptor agonists (GLP-1 RAs), injectableglucagon-like peptide 1(GLP-1)/ glucose-dependent insulinotropic polypeptidereceptor agonist (GIP RA) combination products.

• Body mass index (BMI) ≤ 40.0 kilogram per square meter (kg/m^2).

Exclusion Criteria:

• Any episodes of diabetic ketoacidosis within 90 days prior to the day of screening.

• Myocardial infarction, stroke, hospitalisation for unstable angina pectoris ortransient ischaemic attack within 180 days prior to the day of screening.

• Chronic heart failure classified as being in New York Heart Association Class IV atscreening.

• Anticipated initiation or change in concomitant medications (for more than 14consecutive days) known to affect weight or glucose metabolism (e.g., treatment withorlistat, thyroid hormones, or corticosteroids).

• Uncontrolled and potentially unstable diabetic retinopathy or maculopathy. Verifiedby a fundus examination performed within the past 90 days prior to screening or inthe period between screening and randomisation. Pharmacological pupil-dilation is arequirement unless using a digital fundus photography camera specified fornon-dilated examination.