Both glimepiride and high-dose metformin are important for sustained glucose lowering in Japanese type 2 diabetes patients on glimepiride-sitagliptin-metformin therapy: subanalysis of a single-center, open-label, randomized study.

BACKGROUND: In a previous single-center, open-label randomized 3-month study of triple oral antidiabetes drug (OAD) therapy, we investigated factors affecting the glycemic control afforded by sitagliptin, high-dose metformin, and low-dose glimepiride. Patients were prospectively assigned to either Group 1 (50% reduction in metformin) or Group 2 (discontinuation of glimepiride) and compared. The results showed that the glycated hemoglobin (HbA1c) levels of patients in Group 2 deteriorated more than those in Group 1, whereas HbA1c levels were maintained in some patients in both groups. MATERIALS AND METHODS: To determine the factors associated with maintenance of HbA1c under this triple OAD regimen, data from the prospective study were further analyzed. RESULTS: In both Groups 1 and 2, the baseline HbA1c level was higher in patients with HbA1c ≥7.0% after 3 months of treatment than those with an HbA1c level of <7.0%. A generalized linear model revealed that high-dose metformin was associated with a deterioration of HbA1c levels in Group 2. CONCLUSIONS: Together, the findings indicate that glimepiride and high-dose metformin are important for sustained glycemic control in triple OAD therapy with sitagliptin, metformin, and sulfonylurea.

Glimepiride strongly enhances the glucose-lowering effect in triple oral antidiabetes therapy with sitagliptin and metformin for Japanese patients with type 2 diabetes mellitus.

BACKGROUND: After approval of sitagliptin and >750 mg of metformin in Japan, a triple oral antidiabetes drug (OAD) regimen including sulfonylurea, metformin, and sitagliptin was sometimes described. However, in the real world of clinical practice, the daily dose of sulfonylurea tended to be decreased according to the warning from the Japan Diabetes Society for avoiding hypoglycemia, instead of increasing the dose of metformin for maintaining hemoglobin A1c (HbA1c) levels with this regimen. This study examined the impact of either a small dose of glimepiride or a high dose of metformin on HbA1c in triple OAD therapy with sitagliptin in a 3-month, single-center, open-label, randomized controlled study. SUBJECTS AND METHODS: Fifty-six type 2 diabetes mellitus patients who had been treated with 50 mg of sitagliptin, ≥ 1,000 mg of metformin, and ≤ 1 mg of glimepiride with an HbA1c level of <7.4% during at least 3 months were enrolled in the study. The patients were randomly assigned to two treatment groups who either received a 50% reduced dose of metformin (n = 27) or discontinued glimepiride (n = 29), while sitagliptin administration continued in both groups. Twenty-six patients from the reduced metformin group and 27 patients from the discontinued glimepiride group completed the study. RESULTS: Significantly greater changes were observed in HbA1c and glycated albumin levels in patients who discontinued glimepiride than in patients with a 50% reduced metformin dose, during the 2-3-month period than in the 1-3-month period. CONCLUSIONS: Glimepiride is important for good glycemic control in triple OAD therapy with sitaglitpin and metformin. This regimen may be useful for those patients who do not achieve satisfactory glycemic control with dual combination therapy.

Combination Therapy with a Dipeptidyl Peptidase-4 Inhibitor, Sulfonylurea, and Metformin Markedly Improves HbA1c Levels in Japanese Patients with Type 2 Diabetes Mellitus.

Combination therapy with a dipeptidyl peptidase (DPP)-4 inhibitor and metformin or sulfonylurea results in substantial and additive glucose-lowering effects in patients with type 2 diabetes mellitus (T2DM). However, it is not known whether triple combination therapy with a DPP-4 inhibitor, metformin, and sulfonylurea has greater additive effects or synergic effects. In the present report, we investigated the effect of addition of sitagliptin, the first-in-class DPP-4 inhibitor, to ongoing metformin and sulfonylurea therapy in three female Japanese patients with T2DM who refused insulin therapy. Combined treatment with all three drugs resulted in marked improvements in HbA1c. In the first patient, HbA1c levels decreased from 11.1% to 6.1% after the addition of sitagliptin to metformin 1000 mg, glibenclamide, and miglitol, even though the dose of glibenclamide was decreased. HbA1c levels decreased similarly in the second patient, who was being treated with metformin and glibenclamide, from 7.9% to 6.0% after addition of sitagliptin and an increase in metformin to 2250 mg; this patient ceased glibenclamide because of hypoglycemia and instead was started on low-dose glimepiride. In the third patient, HbA1c levels decreased from 8.6% to 7.1% after addition of glimepiride to ongoing sitagliptin and metformin therapy. All three patients had refused insulin therapy, despite the fact that ongoing combination therapy had failed to achieve satisfactory glycemic control. Based on these results, it is likely that the addition of sitagliptin to metformin and at least a small dose of sulfonylurea may be effective in reducing HbA1c levels without weight gain. This triple combination therapy may prove useful in at least some patients who need initiation of insulin therapy.