The other four studies compared the effects of Galvus, taken at doses of 50 or 100 mg a day for 24 weeks, with those of placebo, when used as an add-on to existing treatment with metformin (544 patients), pioglitazone (a thiazolidinedione, 463 patients), glimepiride (a sulphonylurea, 515 patients) or insulin (296 patients).