This 6 arm study will evaluate the efficacy, safety, pharmacokinetics and pharmacodynamics of multiple doses and regimens of a GLP-1 analogue in patients with type 2 diabetes who are treated with a stable dose of metformin. Patients will be randomized to receive either subcutaneous placebo, or subcutaneous GLP-1 analogue, 5mg, 10mg or 20mg weekly, or 10mg or 20mg every 2 weeks. All patients will continue on their existing metformin treatment regimen throughout the study. The anticipated time on study treatment is <3 months, and the target sample size is 100-500 individuals.

Inclusion Criteria:

• adult patients, 18-75 years of age;
• type 2 diabetes mellitus, with stable metformin treatment for >=3 months;
• stable weight +/-10% for >=3 months before screening.

Exclusion Criteria:

• type 1 diabetes mellitus;
• treatment with any anti-hyperglycemic medication other than metformin monotherapy during last 3 months;
• use of weight-lowering medications in the last 3 months;
• uncontrolled hypertension.