Comparison of the Effects of Repaglinide and Metformin on Glucose Excursions

This is a 17 week, randomized, single center, open-label, parallel-group study to compare glucose excursions and other efficacy and safety parameters of repaglinide thrice daily or metformin thrice daily in newly diagnosed type 2 diabetes subjects in China.

Eligibility for participation will be determined by medical history, physical examination, and laboratory results obtained during a screening visit (see trail population). About 60 patients with newly diagnosed (within 6 months) type 2 diabetes and both insulin and oral antidiabetic drugs (OAD) naïve will be include in this study. All subjects will be given informed consent before starting any examination and test. Then the 24h blood glucose of each patient will be recorded by utilizing continue glucose monitor system (CGMS). Besides that, the following data of all subject will be collected: HbA1c, Fasting blood glucose, 2h postprandial blood glucose, fasting lipid profile, 2h postprandial lipid profile, fasting uric acid, 2h postprandial uric acid, fasting insulin and proinsulin, 2h postprandial insulin and proinsulin, fasting C peptide, 2h postprandial C peptide, fasting glucagon, 2h postprandial glucagon.

After baseline data are collected, eligible subjects will be randomized into each group at a 2:1 ratio (40 for repaglinide and 20 for metformin). IVGTT and hyperinsulinemic-euglycemic clamp will be done to 20 patients in repaglinide group and 10 patients in metformin group (less than 20% drop-off rate is acceptable for this study). Follow that, all patients will start to receive either repaglinide thrice daily (immediately before breakfast lunch, and dinner) or metformin thrice daily (after breakfast, lunch and dinner). The initial repaglinide doses will be based on HbA1c levels on the day of randomization (0.5 mg tid for HbA1c < 8% and 1 mg tid for HbA1c ≥ 8%); the initial dosage for metformin will be 0.5 g tid and this dosage will be kept until the end of this study.

Treatment diaries will be asked for every subject to record glucose levels (7 times per day and 2 days per week for the first three weeks, then 7 times per day and 1 day per week until the end of this study), diet and exercise, stress situation, hypoglycemic symptoms and so on. All patients will be followed by visiting clinic every week for the first three weeks, but only patients in repaglinide group will be titrated their doses. Dose adjustment should be aimed at achieving the following glycemic targets: fasting blood glucose: 4.4 - 6.0 mmol/L, 2h post prandial glucose 4.4 - 8.0 mmol/L. If above glycaemic target has not been achieved, repaglinide dose should be adjusted for every week (see Schematic diagram of trial design). The adjustment of repaglinide doses is based on the mean of blood glucose recorded in subject diaries. The doses of repaglinide before each meal may be different, depending on the recorded blood glucose concentrations. After three weeks titration for repaglinide (maximal dosage for repaglinide is 2 mg tid), the patients in this group will keep the optimal dosage for the next 12 weeks. Clinic visit will be conducted every four weeks after the period of dosages titration to collect information, such as hypoglycemia, adverse events and fasting blood glucose.

Complicated examinations will be repeated again after above 12 weeks treatments for both groups, including physical examination, electrocardiogram (ECG), CGMS, fasting and 2h post prandial glucose, concentration of insulin, proinsulin, C peptide, glucagon, uric acid and so on. IVGTT and hyperinsulinemic-euglycemic clamp will be repeated only for subjects who did that at the beginning of study. Data will be collected and analyzed.