Randomized, Active Controlled, Open Label Study to Compare Taspoglutide vs Exenatide as add-on Treatment to Metformin and/or Thiazolidinediones in Patients With Type 2 Diabetes Mellitus

This 3-arm study will assess the efficacy, safety and tolerability of taspoglutide compared with exenatide in patients with type 2 diabetes mellitus inadequately controlled with metformin, thiazolidinedione or a combination of both. Patients will be randomized to receive taspoglutide (10mg once weekly or 10mg once weekly for 4 weeks followed by 20mg once weekly) or exenatide (5 micrograms twice daily for 4 weeks followed by 10 micrograms twice daily) in a ratio of 1:1:1 in addition to continued prestudy metformin and thiazolidinedione either alone or in combination. The anticipated time on study treatment is 3+ years, and the target sample size is \>500 individuals.