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

A Study to Evaluate the Efficacy and Safety of Once-weekly Insulin Icodec When Switching From Daily Basal Insulins Compared to Once-daily Insulin Glargine U100 in Adults With Type 2 Diabetes

This study compares insulin icodec, a new insulin taken once a week, to insulin glargine, an insulin taken once a day. The study medicine will be investigated in participants with type 2 diabetes. Participants will either get insulin icodec or insulin glargine. Which treatment participants get is decided by chance. Insulin icodec is the new medicine being tested, while insulin glargine is already approved and can be prescribed by doctors. Participants will get one injection of insulin icodec once a week, or one injection of insulin glargine once a day, depending on the treatment group participants are assigned into. Participants will use a pen with a small needle to inject the medicine under participants skin into participants thigh, upper arm or stomach.The study will last for about 9 months, but participants will only be taking the study medicine for 6 months.

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 by central laboratory analysis.
• Treated with once-daily or twice-daily basal insulin (Neutral Protamine Hagedorn insulin, insulin degludec, insulin detemir, insulin glargine 100 U/mL, or insulin glargine 300 U/mL) ≥ 90 days prior to the day of screening with or without any of the 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, oral combination products (for the allowed individual oral anti- diabetic drugs), oral or injectable glucagon-like peptide 1 receptor agonists (GLP-1 RAs), injectable glucagon-like peptide 1(GLP-1)/ glucose-dependent insulinotropic polypeptide receptor 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 or transient ischaemic attack within 180 days prior to the day of screening.
• Chronic heart failure classified as being in New York Heart Association Class IV at screening.
• Anticipated initiation or change in concomitant medications (for more than 14 consecutive days) known to affect weight or glucose metabolism (e.g., treatment with orlistat, thyroid hormones, or corticosteroids).
• Uncontrolled and potentially unstable diabetic retinopathy or maculopathy. Verified by a fundus examination performed within the past 90 days prior to screening or in the period between screening and randomisation. Pharmacological pupil-dilation is a requirement unless using a digital fundus photography camera specified for non-dilated examination.