This 3-arm study will assess the efficacy, safety and tolerability of taspoglutide compared to insulin glargine in patients with insulin-naive type 2 diabetes mellitus inadequately controlled with metformin and sulphonylurea combination therapy. Patients will be randomized to receive taspoglutide (10 mg once weekly, or 10mg once weekly for 4 weeks followed by 20mg once weekly) or insulin glargine (starting dose 10 IU/day) in a ratio of 1:1:1 in addition to continued prestudy metformin treatment. The anticipated time on study treatment is 2+ years, and the target sample size if 500+ individuals.

Inclusion Criteria:

• adult patients, 18-75 years of age;
• type 2 diabetes treated with a stable dose of metformin and sulphonylurea for at least 12 weeks;
• C-peptide (fasting) >=1.0ng/mL;
• HbA1c >=7.0% and <=10.0% at screening;
• BMI >=25 (>23 for Asians) and <=45kg/m2 at screening;
• stable weight +-5% for at least 12 weeks prior to screening.

Exclusion Criteria:

• history of type 1 diabetes mellitus or acute metabolic diabetic complications such as ketoacidosis or hyperosmolar coma in the previous 6 months;
• evidence of clinically significant diabetic complications;
• symptomatic poorly controlled diabetes;
• clinically symptomatic gastrointestinal disease;
• myocardial infarction, coronary artery bypass surgery, post-transplantation cardiomyopathy or stroke within the previous 6 months;
• known hemoglobinopathy or chronic anemia.