A Study of LY3457263 Compared With Placebo in Participants With Type 2 Diabetes on a Stable Dose of Semaglutide or Tirzepatide

The purpose of this study is to measure the change in hemoglobin A1c (HbA1c) with LY3457263 compared with placebo in participants with type 2 diabetes who are not at HbA1c goal when treated with a stable dose of semaglutide or tirzepatide. Participation in the study will last about 9 months.

Inclusion Criteria: * Have type 2 diabetes * Have HbA1c ≥7.5% to ≤10.5% at screening * Have a body mass index (BMI) of ≥27 kilograms per square meter (kg/m2) at screening * Have had a stable body weight for the three months prior to screening * On stable treatment dose of one of the following incretins for at least three months prior to screening: * Injectable semaglutide (1 and 2 milligram (mg)) * Injectable tirzepatide (5, 7.5, 10, 12.5 and 15 mg) Exclusion Criteria: * Have type 1 diabetes, latent autoimmune diabetes, or history of ketoacidosis or hyperosmolar coma * Have a prior or planned surgical treatment for obesity * Have any of the following cardiovascular conditions within three months prior to screening: * acute myocardial infarction * cerebrovascular accident (stroke) * unstable angina, or * hospitalization due to congestive heart failure * Have used insulin to control blood glucose within the past year (short-term use allowed) * Current use of prohibited oral antihyperglycemic medication (OAM) (including but not limited to, Dipeptidyl Peptidase IV Inhibitors (DPP-4i) and meglitinides) may be randomized if the prohibited OAM treatment was discontinued at least 3 months prior to screening * If participant has been on stable doses (for at least three months) of up to three permitted OAMs (limited to metformin, sodium-glucose cotransporter-2 (SGLT2) inhibitors, alpha-glucosidase inhibitors, sulfonylurea, and/or thiazolidinediones (TZD), they are permitted to participate in the study * Have taken any medications or alternative remedies for weight loss within three months prior to screening