Combination therapy with insulin glargine plus metformin but not insulin glargine plus sulfonylurea provides similar glycemic control to triple oral combination therapy in patients with type 2 diabetes uncontrolled with dual oral agent therapy.

AIMS: Evaluate substituting insulin glargine (GLAR) for a thiazolidinedione (TZD) versus adding a third oral antidiabetes drug (OAD) in patients with uncontrolled type 2 diabetes mellitus (T2DM) on TZD+metformin or TZD+sulfonylurea.

METHODS: In this multicenter, open-label study, 337 T2DM patients with a glycated hemoglobin A1c (A1C) of 7.5-12.0% despite≥3months of treatment with a TZD plus metformin or a sulfonylurea were randomized to a third OAD (3OAD; metformin or glyburide) or GLAR+1 OAD (metformin or sulfonylurea) with TZD cessation, titrated to a fasting blood glucose≤94mg/dL.

RESULTS: Substitution of GLAR for a TZD led to an adjusted mean A1C change from baseline of-1.66% versus-1.86% in the 3OAD arm (adjusted mean difference 0.20 [95% confidence interval, - 0.11, 0.51], not meeting the noninferiority criteria). This difference was driven by the GLAR+sulfonylurea stratum. GLAR+metformin was as effective as 3OAD in achieving glycemic control but with greater improvements in lipid parameters, less weight gain, and lower hypoglycemia rates.

CONCLUSIONS: These findings favor substitution of GLAR for a TZD in T2DM patients not controlled on TZD+metformin. GLAR+sulfonylurea was less effective at lowering A1C than 3OAD and not associated with the benefits observed with GLAR+metformin.