Repaglinide is more efficient than glimepiride on insulin secretion and post-prandial glucose excursions in patients with type 2 diabetes. A short term study

Effect of repaglinide, administered two or three times daily for 3 months, on glycaemic control in Japanese patients with type 2 diabetes mellitus

OBJECTIVES

To compare the efficacy, safety and compliance of repaglinide, administered either two or three times daily, regarding glycaemic control in patients with type 2 diabetes mellitus.

METHODS

Japanese adults with type 2 diabetes mellitus, who had been treated without sulphonylureas or glinides for >3 months, were randomly assigned to two groups to receive either 0.25 mg repaglinide, oral, twice daily (group A) or 0.25 mg repaglinide, oral, three times daily (group B). Glycosylated haemoglobin (HbA1c), glycoalbumin (GA) and 1,5-anhydroglucitol (1,5-AG) levels were measured at 0, 1, 2 and 3 months after treatment commenced.

RESULTS

Out of 43 patients who enrolled (group A, n = 22; group B, n = 21), 33 patients completed the trial (group A, n = 16; group B, n = 17). No significant between-group differences in HbA1c, GA, or 1,5-AG levels were seen at 1-3 months. No severe hypoglycaemic episodes or other adverse events were observed.

CONCLUSIONS

Minimal-dose repaglinide administered twice daily was similar in efficacy and safety to three-times-daily administration, in Japanese patients with type 2 diabetes mellitus. Administration of repaglinide twice daily could be an alternative regimen for patients who cannot take repaglinide three times daily.

Effect of repaglinide versus glimepiride on daily blood glucose variability and changes in blood inflammatory and oxidative stress markers

BACKGROUND

Hemoglobin A1c is the main treatment target for patients with type 2 diabetes. It has also been shown recently that postprandial glucose and daily glucose fluctuations affect the progression of diabetic complications and atherosclerotic damages.

METHODS

Continuous glucose monitoring was performed in patients with type 2 diabetes to evaluate the efficacy of repaglinide vs. glimepiride on postprandial glucose spikes and fluctuations. A total of 10 Japanese patients with type 2 diabetes treated with glimepiride monotherapy were enrolled. After observation period for 8 weeks, glimepiride was changed to repaglinide. Continuous glucose monitoring was performed whilst consuming calorie-restricted diets for two days at baseline and at the end of the 12-week trial. Blood and urine samples were collected for measurement of glucose control parameters and inflammatory and oxidative stress markers on the last day of taking either glimepiride or repaglinide.

RESULTS

Nine patients completed the trial. Although the glucose control parameters were not significantly different between glimepiride and repaglinide, the mean amplitude of glycemic excursions measured by continuous glucose monitoring was significantly reduced by changing treatment from glimepiride to repaglinide. The levels of plasminogen activator inhibitor-1, high sensitivity C-reactive protein, and urinary 8-hydoroxydeoxyguanosine were reduced significantly by repaglinide treatment.

CONCLUSION

These results suggest that repaglinide may decrease the risk of cardiovascular disease in type 2 diabetes by minimizing glucose fluctuations thereby reducing inflammation and oxidative stress.

Effect of the urotensin-II receptor antagonist palosuran on secretion of and sensitivity to insulin in patients with Type 2 diabetes mellitus

AIMS

To investigate the effects of palosuran, a nonpeptidic, potent and selective antagonist of the urotensin-II receptor, on insulin and glucose regulation in 20 diet-treated patients with Type 2 diabetes mellitus in a double-blind, placebo-controlled, randomized, crossover, proof-of-concept study.

METHODS

After 4 weeks' oral treatment with 125 mg palosuran or placebo b.i.d.,effects on insulin secretion and sensitivity and blood glucose levels were assessed by means of a hyperglycaemic glucose clamp, meal tolerance test, homeostasis model assessment-insulin resistance score, and daily self-monitoring of blood glucose. Plasma concentrations of palosuran were determined for 12 h on the last day of intake.

RESULTS

Palosuran did not affect second-phase insulin response (primary end-point) during the hyperglycaemic glucose clamp in comparison with placebo [paired difference of -1.8 microU ml(-1), 95% confidence interval (CI) -7.8, 4.2]. Likewise, no effects of palosuran were detected on the first-phase insulin response, or on insulin secretion and blood glucose levels during the meal tolerance test or on homeostasis model assessment-insulin resistance score. No clinically significant effects on daily blood glucose profiles were observed during the study. Geometric mean C(max) and AUC(tau) (95% CI) and median t(max) (range) in this patient population were 180 ng ml(-1) (125, 260), 581 ng.h ml(-1) (422, 800) and 3.0 h (0.67, 4.3), respectively.

CONCLUSIONS

The results of this study indicate that antagonism of the urotensin-II system does not influence insulin secretion or sensitivity or daily blood glucose levels in diet-treated patients with Type 2 diabetes.

Association of KCNJ11 and ABCC8 genetic polymorphisms with response to repaglinide in Chinese diabetic patients

AIM

The aim of this study was to investigate the association of KCNJ11 E23K and ABCC8 exon16-3T/C with the therapeutic effect of repaglinide in patients with type 2 diabetes.

METHODS

A total of 100 Chinese patients with newly diagnosed type 2 diabetes were treated with repaglinide for 24 weeks. Arginine stimulation tests were performed to evaluate beta cell function. Gene variations were detected with PCR-restriction fragment length polymorphism. Responders were defined by a greater than 25% decrease in fasting plasma glucose or a greater than 20% decrease in hemoglobin A1c (HbA1c) values (or both) after the 24 week repaglinide treatment.

RESULTS

Both baseline HbA1c and the decrease of HbA1c were significantly higher in patients with E/K and K/K genotypes of the KCNJ11 E23K variant when compared with E/E homozygotes (P=0.0103 and 0.0221, respectively). The decrease in 2 h postprandial plasma glucose (2hPG) was significantly greater in E/K heterozygotes than E/E homozygotes (P=0.0367). There was a significant difference in the response rate to repaglinide treatment between the E and K alleles (68% vs 82%, P=0.0324). The changes in fasting insulin and the homeostasis model assessment of insulin resistance were significantly greater in patients with ABCC8 exon16-3 C/C versus the T/C and T/T genotypes (P=0.0372 and 0.0274, respectively).

CONCLUSION

The KCNJ11 E23K variant was associated with the therapeutic effect of repaglinide. In addition, The C/C homozygotes of the ABCC8 exon16-3T/C variant responded better to repaglinide in insulin sensitivity than the T/C and T/T genotypes.

Defining the role of repaglinide in the management of type 2 diabetes mellitus: a review

Type 2 diabetes mellitus (T2DM) is characterized by hyperglycemia due to a combination of insulin resistance and impaired insulin secretion. The hyperglycemia is associated with an increased risk for micro- and macrovascular complications, and lowering fasting and postprandial hyperglycemia may be protective against these complications. Repaglinide is an insulin secretagogue that lowers blood glucose levels in patients with T2DM. We review the effects of repaglinide in patients with T2DM, its impact on glycemia and its non-glycemic effects, and its effects when used in special situations or patient populations. Results from randomized controlled trials, observational studies, and safety reports involving humans and published in the English-language through 1 May 2007 identified by a search in PubMed/MEDLINE were evaluated. Present knowledge indicates that repaglinide reduces fasting and postprandial hyperglycemia and the level of glycosylated hemoglobin (HbA1c) in patients with T2DM. It is at least as effective in reducing HbA1c and fasting plasma glucose as sulphonylureas, metformin, or the glitazones and in combination therapy with other drugs, repaglinide is as effective as any other combination. Some studies show a better effect of repaglinide on postprandial glycemia than the comparators. Its propensity to induce hypoglycemia is similar to or a little less than that of sulphonylureas. Repaglinide is associated with less weight gain than sulphonylureas and the glitazones. Repaglinide has primarily a role in the treatment of T2DM when metformin cannot be used due to adverse effects, when metformin fails to adequately control blood glucose levels, when there is a need for flexible dosing (i.e. the elderly or during Ramadan fasting), or when there is a specific wish to lower postprandial glucose. Repaglinide may also have an advantage when an oral agent is needed in diabetic patients with renal impairment. Because of its short duration of action, repaglinide should be taken before each meal, usually at least three times a day. Although no study has investigated whether repaglinide lowers total mortality or cardiovascular endpoints, several studies indicate beneficial effects on cardiovascular surrogate endpoints, such as carotid intima-media thickening, markers of inflammation, platelet activation, lipid parameters, endothelial function, adiponectin, and oxidative stress. In conclusion, repaglinide is a compound that can be used in both mono- and combination therapy for the treatment of both fasting and postprandial hyperglycemia in patients with T2DM. It can be used in patients at different stages of the disease, from uncomplicated to severe renal impairment. Although the drug has been tested in a large number of clinical trials and observational studies, its world-wide use is far less than, for example, sulphonylureas. Repaglinide may offer an additional potential for lowering blood glucose levels in T2DM that until now has not been fully realized by many clinicians.

A randomized controlled trial examining combinations of repaglinide, metformin and NPH insulin

AIMS

To compare combination use of repaglinide, metformin and bedtime Neutral Protamine Hagedorn (NPH) insulin with conventional approaches of insulin initiation in patients with Type 2 diabetes (T2DM).

METHODS

Eighty-two patients with T2DM with suboptimal glycaemic control on oral glucose-lowering agents were randomized to one of three treatment regimens for 4 months. Group 1 received metformin and twice daily biphasic 30/70 human insulin mixture (n = 27), group 2 metformin and bedtime NPH insulin (n = 26) and group 3 metformin, bedtime NPH insulin and mealtime repaglinide (n = 25).

RESULTS

Seventy-five patients completed the study. Baseline and end-point mean HbA1c levels fell from 9.0 +/- 1.1 to 7.9 +/- 1.1% in group 1, 10.0 +/- 2.2 to 9.2 +/- 1.4% group 2 and 10.0 +/- 1.7 to 8.1 +/- 1.5% in group 3, respectively. All groups showed improvements in HbA1c. There was no significant difference between groups in the proportions of patients experiencing hypoglycaemia (29.6, 25.0 and 16.7%, respectively; P = 0.55) or in mean weight gain (2.9, 0.7 and 2.2 kg, respectively; P = 0.06). By 4 months, insulin doses were 0.63 +/- 0.32 IU/kg in group 1, 0.58 +/- 0.21 IU/kg in group 2 and 0.37 +/- 0.22 IU/kg in group 3 (group 3 vs. groups 1 and 2: P < 0.002).

CONCLUSIONS

The approach using repaglinide, metformin and NPH insulin improved glycaemic control with a similar safety profile to conventional insulin initiation in T2DM and produced final glycaemic control similar to metformin and a twice daily biphasic insulin mixture.

Targeting postprandial hyperglycemia

In healthy individuals, blood glucose levels in the fasting state are maintained by the continuous basal-level insulin secretion. After a meal, the rise in postprandial glucose (PPG) is controlled by the rapid pancreatic release of insulin, stimulated by both glucose and the intestinal production of the incretins glucose-dependent insulinotropic polypeptide and glucagon-like peptide 1. In diabetic individuals, postprandial insulin secretion is insufficient to suppress an excessive rise in PPG. There is increasing evidence that elevated PPG exerts a more deleterious effect on the vascular system than elevation of fasting plasma glucose. In particular, individuals with normal fasting plasma glucose but impaired glucose tolerance have significantly increased risk of cardiovascular events. With the recognition of the importance of PPG and the availability of new pharmacologic options, management of diabetes will shift to greater attention to PPG levels. The prototype for such an approach is in the treatment of gestational diabetes and diabetic pregnancies where PPG is the primary target of efforts at glycemic control. These efforts have been extremely successful in improving the outlook for diabetic pregnant women. There are many approaches to reduction of PPG; dietary management and promotion of exercise are very effective. Sulfonylureas, meglitinides, metformin, thiazolidinediones, and disaccharidase inhibitors all counteract PPG elevation. The development of glucagon-like peptide 1 agonists such as exendin and dipeptidyl peptidase IV inhibitors such as vildagliptin offers a new approach to suppression of PPG elevation. New semisynthetic insulin analogues permit a more aggressive response to postprandial glucose elevation, with lower risk of hypoglycemia, than with regular insulin. Inhaled insulin also has a rapid onset of action and offers benefits in PPG control. It is proposed that an aggressive treatment approach focusing on PPG, similar to the current standards for diabetic pregancies, be directed at individuals with diabetes and impaired glucose tolerance.

Meglitinide analogues: a review of clinical data focused on recent trials

Glinides represent a chemically heterogeneous new class of insulin-secreting agents characterized by a rapid onset and short duration of action. They act by closure of the ATP-dependant K channel. Repaglinide, the only glinide available in France, has an equivalent HbA1c lowering effect to conventional sulfonylureas but reduces predominantly postprandial glucose levels. Several studies indicate a decreased risk of hypoglycaemias, particularly nocturnal or in case of a shift or omission of a meal. This drug appears particularly useful in early stage type 2 diabetes or in combination with metformin. The only significant drug-drug interaction concerns gemfibrozil. Due to its hepatic metabolism and biliary elimination, repaglinide can be used in patients with renal insufficiency. Nateglinide has a even shorter duration of action and has almost no effect on fasting plasma glucose levels. For this reason, this drug is only indicated in combination with metformin in the countries where it is licensed. Several experimental data suggest that glinides could preserve B cell function over time better than hypoglycaemic sulfonylureas, and that the improvement of post-prandial glucose levels could exert a long term protective cardiovascular effect.

Beta-cell response during a meal test: a comparative study of incremental doses of repaglinide in type 2 diabetic patients

OBJECTIVE

To assess the effects of incremental doses of repaglinide on postprandial insulin and glucose profiles after a standard 500-kcal test meal.

RESEARCH DESIGN AND METHODS

Sixteen diet-treated Caucasians with type 2 diabetes (mean HbA(1c) 8.4%) were enrolled in this randomized, open-label, crossover trial. Subjects received 0.5, 1, 2, and 4 mg repaglinide or placebo in a random fashion, followed by a standard 500-kcal test meal on 5 separate study days, 1 week apart.

RESULTS

The insulinogenic index (DeltaI30/DeltaG30) and insulin area under the curve (AUC) from 0 to 30 min (AUC(0-30)) were higher with the 4-mg drug dose compared with the two lower doses and with 2 mg compared with 0.5 mg. On subgroup analysis, the incremental insulin responses were apparent only in the fasting plasma glucose (FPG) < 9-mmol/l subgroup of subjects and not in the FPG >9-mmol/l subgroup. There was a significant dose-related increase in the late postprandial insulin secretion (insulin AUC(120-240)), which resulted in hypoglycemia in four subjects. Proinsulin-to-insulin ratios at 30 and 60 min improved with increasing doses of repaglinide; higher drug doses (2 and 4 mg) were more effective than the 0.5- and 1-mg doses.

CONCLUSIONS

Significant dose-related increases in early insulin secretion were found only in less advanced diabetic subjects. In advanced diabetic patients, only the maximum dose (4 mg) was significant compared with placebo. Better proinsulin-to-insulin processing was noted with increasing drug doses.