- Have been treated with a stable dose of TZD (≥4 mg/day rosiglitazone or ≥30 mg/day pioglitazone) for at least 120 days prior to Visit 1 OR Have been treated with a stable dose of TZD (≥4 mg/day rosiglitazone or ≥30 mg/day pioglitazone) for at least 120 days PLUS a stable dose of metformin for at least 90 days prior to Visit 1.