This study is to test the efficacy and safety of PHX1149T in combination with metformin, a glitazone, or metformin and a glitazone in subjects with Type 2 diabetes for 12 weeks. After completing the 12 week double blind part of the study, subjects can enter an open label extension study

Key Entry Criteria:

• Type 2 diabetes mellitus, diagnosed at least 4 months but not more than 12 years prior to screening.
• Male and non-pregnant, non-lactating (and not planning to become pregnant during the study) female subjects with a BMI of 25 to 48 kg/m2, inclusive. For India the BMI is 23 to 48 kg/m2, inclusive.
• Current treatment of Type 2 diabetes mellitus with a stable dose of metformin of 1500 mg or more (or the highest tolerated dose), or TZD (any labeled dose), or metformin + TZD at doses used in accordance with product labeling for at least 4 weeks (metformin) or 10 weeks (TZD) prior to screening (Visit 1).
• Fasting plasma glucose of 118 - 220 mg/dL (6.6 - 12.2 mmol/L), inclusive; HbA1c 7.3% - 11.0%, inclusive; and a fasting plasma C peptide greater than 0.26 nmol/L at screening. For Argentina the allowed upper limit of HbA1c is ≤ 10.5%. For Canada the upper limit will be 10.0%
• No Type 1 diabetes mellitus or marked diabetic long-term complications.