Research Study to Compare a New Medicine "Fast-acting Insulin Aspart" to Another Medicine "Insulin Aspart" in Chinese People With Diabetes

Efficacy and Safety of Fast-acting Insulin Aspart Compared to NovoRapid® Both in Combination With Insulin Degludec With or Without Metformin in Adults With Diabetes

Fast-acting insulin aspart (faster aspart) will be tested to see how well it works and if it is safe. The study compares 2 medicines for type 1 and type 2 diabetes - faster aspart (a new medicine) and insulin aspart (a medicine doctors can already prescribe). Participants will either get faster aspart or insulin aspart (NovoRapid®) - which treatment is decided by chance. Both medicines will be taken together with insulin degludec. Participants will need to take 1 injection 4 times every day: 3 injections 0-2 minutes before breakfast, lunch and dinner and 1 injection at the same time every day. All study medicines are provided in pens. A pen is a tool to inject insulin under the skin.The study will last for about 7 months (30 weeks). Participants will have 11 clinic visits and 17 phone contacts with the study doctor. At 8 clinic visits participants will have blood samples taken. At 3 clinic visits participants cannot eat or drink (water is allowed) 8 hours before the visits - at 2 of these visits participants will be asked to drink a liquid meal and to stay at the clinic for about 5 hours. Participants will fill in a diary the last 3 days before the visits/phone contacts. Women cannot take part if pregnant, breast-feeding or planning to become pregnant during the study period.

Inclusion Criteria:

• Male or female, age above or equal to 18 years at the time of signing informed consent
• Diagnosed with Diabetes Mellitus, Type 1 (T1DM) at least or equal to 1 year prior to screening or diagnosed with Diabetes Mellitus, Type 2 (T2DM) at least or equal to 5 years prior to screening
• Treated with a basal-bolus insulin regimen or a premix insulin regimen at least or equal to 1 year prior to screening. Insulin regimen must be unchanged within 60 days prior to screening. A basal-bolus insulin regimen is defined as basal insulin once or twice daily and bolus insulin taken with meals at least thrice daily. A premix insulin regimen is defined as premix insulin twice or thrice daily
• For subjects with T1DM: not treated with any oral anti-diabetes drugs (OADs) for at least 90 days prior to screening. For subjects with T2DM: not treated with any OADs or treated with 1-2 OADs within 90 days prior to screening. Allowed OADs are metformin, alpha-glucosidase inhibitor, sodium-glucose co-transporter-2 inhibitors (SGLT2i) and dipeptidyl peptidase-4 inhibitors (DPP4i). Change in OAD and dose prior to screening is allowed.
• HbA1c 7.5-9.5% (both inclusive) as assessed by central laboratory at screening

Exclusion Criteria:

• Any of the following: myocardial infarction, stroke, hospitalisation for unstable angina pectoris or transient ischaemic attack within the past 180 days prior to the day of screening
• Subjects presently classified as being in New York Heart Association (NYHA) Class IV
• Planned coronary, carotid or peripheral artery revascularisation known on the day of screening
• Treatment with any medication for the indication of diabetes or obesity other than stated in the inclusion criteria within the past 90 days prior to the day of 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)