4. Currently on stable metformin therapy (unchanged dose for greater than or equal to 12 weeks prior to screening). At the discretion of the investigator, subjects who are drug naïve or whose metformin dose has not been stable for at least 12 weeks at screening, may be started on metformin or have their metformin dose stabilized. Following 12 weeks of stable metformin, they may undergo re screening including assessment of HbA1c and FPG (inclusion criteria 5 and 6).