The purpose of this study is to demonstrate the safety and tolerability of dutogliptin over 52 weeks.

Inclusion Criteria:

• Completion of all required visits of a qualifying Phase 3 core protocol
• Current treatment of Type 2 diabetes mellitus as in PHX1149-PROT302

Exclusion Criteria:

• Any condition, disease, disorder or clinically relevant laboratory abnormality which, in the opinion of the investigator, would jeopardize the patient's appropriate participation in this study or obscure the effects of treatment