The aim of the study is to compare the efficacy and safety of two JY09 doses versus dulaglutide as add-on therapy to metformin in participants with type 2 diabetes mellitus (T2DM)

This study was designed as a multicenter, randomized, open, parallel, positively controlled Phase III clinical study to evaluate the efficacy and safety of Exendin-4Fc fusion protein (JY09) injection in adult subjects with type 2 diabetes mellitus who have poor glycemic control after metformin treatment only.

The proposed plan is to enroll 600 subjects with T2DM, using stratified block group randomization with the stratification factor being baseline HbA1c (≤8.5% or >8.5%), and randomly assign them to the 1.2 mg JY09 injection group (n=200 subjects), 2.4 mg JY09 injection group (n=200 subjects) and dulaglutide injection group (n=200 subjects) in a 1:1:1 ratio.

The trial was divided into 4 phases, i.e., a screening period of 2 weeks, an introduction period of 4 weeks, a treatment period of 54 weeks (26 weeks for the core treatment period and 28 weeks for the extended treatment period), and a safety follow-up period of 4 weeks. A total of 64 weeks.

Inclusion Criteria:

1. Male or female subjects ≥18 years of age and ≤75 years of age at the time of signing the informed consent form.
2. Those who meet the World Health Organization（WHO）1999 diagnostic criteria for type 2 diabetes mellitus and the WHO Recommendations for the Use of Glycosylated Haemoglobin (HbA1c) for Diagnosis (2011) supplemental diagnostic criteria for a diagnosis of T2DM for ≥ 12 weeks.
3. Received a stable dose of metformin monotherapy with a metformin dose ≥1500 mg/day or a maximally tolerated dose (<1500 mg/day but ≥1000 mg/day) on the basis of dietary and exercise interventions during the 8 weeks prior to screening.
4. HbA1c ≥7.5% and ≤11.0% at screening (local laboratory) and HbA1c ≥7.0% and ≤10.5% before randomization (V3) (central laboratory).
5. FPG 13.9 mmol/L at screening (local laboratory) and FPG 13.9 mmol/L before randomization (V3) (central laboratory).
6. Body mass index (BMI) ≥18.5 kg/m2 and ≤35.0 kg/m2 at screening and before randomization (V4).
7. Able to understand and willing to sign a written informed consent form (ICF) and comply with the study protocol.

Exclusion Criteria:

1. People diagnosed with type 1 diabetes or other types of diabetes.
2. Those who have used glucose-lowering drugs other than metformin within 8 weeks prior to screening or prior to randomization (V4), or those who have used drugs that may affect glucose metabolism, such as systemic glucocorticosteroids (except for inhalation or topical topical use) and growth hormone.
3. Those who have used glucose-dependent insulinotropic polypeptide (GIP) and/or glucagon-like peptide-1 (GLP-1) receptor agonists (including single-target, multi-target agonists, and insulin-containing GLP-1 combinations) within 3 months prior to screening.
4. More than 14 days of continuous insulin use in the 6 months prior to screening.
5. Acute complications of diabetes such as diabetic ketoacidosis or hyperglycemic hyperosmolar state within 6 months prior to screening or prior to randomization .
6. Severe chronic complications of diabetes mellitus (e.g., proliferative diabetic retinopathy, severe diabetic neuropathy, diabetic foot, etc.) within 6 months prior to screening, which are assessed by the investigator to be unsuitable for participation in this clinical study.
7. Individuals who have had severe gastrointestinal disease (e.g., active ulcer, gastroparesis, pyloric obstruction, inflammatory bowel disease, etc.) or have undergone gastrointestinal surgery within 6 months prior to screening or prior to randomization or who have been using long-term medications for chronic gastrointestinal disease that have a direct effect on gastrointestinal motility are not suitable for participation in this clinical study, as assessed by the investigator.
8. Other conditions that, in the judgment of the investigator, make the subject unsuitable for participation in this clinical study.