This study compares the efficacy, safety, and tolerability of once-weekly GZR4 Injection versus once-daily insulin degludec in patients with type 2 diabetes mellitus in inadquete control on oral antidiabetic drug (OAD) therapy or OAD Therapy in combination with basal insulin.

Inclusion Criteria:

1. Aged 18-75 years (both inclusive) at the time of signing informed consent form (ICF)
2. Body mass index between 18.5 and 35.0 kg/m2 (both inclusive)
3. Diagnosed with type 2 diabetes mellitus above or equal to 6 months
4. 7.5% ≤ HbA1c ≤ 10.0% at screening.

Exclusion Criteria:

1. Female who is pregnant, breast-feeding.
2. Presence or history of malignant neoplasm prior to screening.
3. Diabetic ketoacidosis, diabetic lactic acidosis, or diabetic nonketotic hyperosmolar syndrome within 6 months prior to screening.
4. Known or suspected hypersensitivity to investigational medical product(s) or related products.
5. Severe hypoglycemia (Level 3 hypoglycemia) within 6 months prior to screening
6. History of acute heart failure within 6 months prior to screening or hospitalization for coronary heart disease, myocardial infarction, unstable angina, stroke within 6 months prior to screening.
7. Participation in a clinical study of another study drug within 3 month prior to randomization.