A new study published in Expert Opinion on Pharmacotherapy investigated the safety and efficacy of metformin up titration in Japanese patients with type 2 diabetes mellitus treated with vildagliptin 100 mg day and low dose metformin 500 or 750 mg day . In this randomized trial 50 patients were divided into control group maintaining the initial low dose of metformin and dose increase group up titration of metformin to 1 500 2 250 mg day for 24 weeks. The primary outcome was change in glycated hemoglobin HbA1c from baseline to 24 weeks. It was observed that HbA1c in the dose increase group was significantly but modestly lower than in the control group. While the dose increase group did not gain weight during the study period and no hypoglycemic events were reported in either group. On the other hand the rate of gastrointestinal symptoms in the dose increase group was profoundly higher than the control group. Thus it was concluded that in Japanese patients with type 2 diabetes treated with vildagliptin and low dose metformin metformin up titration significantly but modestly improved glycemic control without hypoglycemia and weight gain.