A Study of Insulin Efsitora Alfa (LY3209590) Compared to Degludec in Adults With Type 2 Diabetes Who Are Starting Basal Insulin for the First Time

Inclusion Criteria:

• Have diagnosis of Type 2 diabetes (T2D) according to the World Health OrganizationCriteria

• Have an Hemoglobin A1c (HbA1c) of 7.0 percent (%) - 10.5% inclusive, at screening

• Are on a stable treatment with 1 to 3 antihyperglycemic medication for at least 3months prior to screening and willing to continue the stable treatment for theduration of the study

• These antihyperglycemic medications are accepted in the study

• dipeptidyl peptidase-4 (DPP-4) inhibitors

• sodium-glucose cotransporter 2 (SGLT2) inhibitors

• biguanides, such as metformin

• alpha-glucosidase inhibitors

• glucagon-like peptide-1 (GLP-1) receptor agonists, oral or injectable

• Sulfonylureas, or

• Thiazolidinediones.

• Are insulin naïve.

Exceptions:

• short-term insulin treatment for a maximum of 14 days, prior to screening, and priorinsulin treatment for gestational diabetes

• Have a body mass index of less than or equal to (≤) 45 kilogram/square meter (kg/m²).

Exclusion Criteria:

• Have a diagnosis of Type 1 diabetes (T1D), latent autoimmune diabetes, or a specifictype of diabetes other than T2D, for example, monogenic diabetes, diseases of theexocrine pancreas, or drug-induced or chemical-induced diabetes.

• Have a history of greater than (>) 1 episode of ketoacidosis or hyperosmolar stateor coma requiring hospitalization within 6 months prior to screening. Have hadsevere hypoglycemia episodes within 6 months prior to screening. Have a history ofrenal transplantation, are currently receiving renal dialysis, or have an estimatedglomerular filtration rate.

• Have known hemoglobinopathy, hemolytic anemia or sickle cell anemia, or any othertraits of hemoglobin abnormalities known to interfere with the measurement of HbA1c.

• Have had New York Heart Association Class IV heart failure or any of thesecardiovascular conditions within 3 months prior to screening

• Acute myocardial infarction

• Cerebrovascular accident (stroke), or

• Coronary bypass surgery.

• Have had gastric bypass (bariatric) surgery, restrictive bariatric surgery, forexample Lap-Band, or sleeve gastrectomy within 1 year prior to screening

• Have had significant weight gain or loss within 3 months prior to screening,for example, greater than or equal to (≥) 5%.