SUSTAIN SWITCH: A Research Study to Compare Two Dose Schedules of Semaglutide Taken Once Weekly in People With Type 2 Diabetes

Inclusion Criteria: * Male or female, age 18 years or older at the time of signing informed consent. * Diagnosed with type 2 diabetes mellitus at least 180 days prior to the day of screening. * The need and willingness to change prior GLP-1 RA treatment to once-weekly semaglutide s.c., as assessed by the investigator. * HbA1c of 6.5-10% (48-86 mmol/mol) (both inclusive). * Treatment with any therapeutic dose of GLP-1 RA other than once-weekly semaglutide s.c., as defined in the local label, with or without OADs (metformin, DPP-4 inhibitor, SU, glinide, thiazolidinedione, SGLT-2 inhibitor or alpha-glucosidase inhibitor). All doses of antidiabetic treatments should have been stable for at least 90 days prior to the day of the screening, at investigator's discretion. Exclusion Criteria: * 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. However, short term insulin treatment for a maximum of 14 days prior to the day of screening is allowed, as is prior insulin treatment for gestational diabetes. * Renal impairment measured as estimated glomerular filtration rate (eGFR) value of less than 30 mL/min/1.73 m2 according to Chronic Kidney Disease Epidemiology Collaboration (CKDEPI) creatinine equation as defined by KDIGO 2012 classification. * 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