Vildagliptin in drug-naïve patients with type 2 diabetes: a 24-week, double-blind, randomized, placebo-controlled, multiple-dose study

A review of newer treatment approaches for type-2 diabetes: Focusing safety and efficacy of incretin based therapy

Diabetes resulting from both genetic and lifestyle factors causes high insulin deficiency or its resistance. As hyperglycemia and decreased insulin secretion and/or its sensitivity appear to be the primary defects associated with diabetes, available treatments focus on reducing those defects. A novel approach of treatment is to target the incretin mimetic hormones, which are secreted by intestinal cells in response to food intake, provoking glucose-dependent insulin secretion from the pancreas. Efficacy and safety studies of dipetidyl peptidase inhibitors (DPP-IV), sitagliptin, vildagliptin and linagliptin provide similar improvements in HbA1c levels when compared with metformin, sulfonylureas or glitazones without contributing to weight gain and hypoglycemia. Caution is required when choosing the gliptin in people with renal or hepatic impairment and with a risk of pancreatitis. The glucagon like peptide (GLP-1) analogues Exenatide and Liraglutide also have positive impact on glycemic control especially when used as a combination therapy. Another upcoming approach is using sodium-glucose co transporter two inhibitors in kidney, by exploring pathophysiology of renal glucose re absorption in the proximal tubule.

Profile of vildagliptin in type 2 diabetes: efficacy, safety, and patient acceptability

Vildagliptin is a selective and potent dipeptidyl peptidase-4 inhibitor that improves glycemic control by inhibiting the degradation of both endogenous glucagon-like peptide-1 and glucose-dependent insulinotropic peptide. This article is a comprehensive review of the safety and efficacy of vildagliptin in patients with type 2 diabetes. Clinical evidence has proven that it effectively decreases hemoglobin A_1c with a low risk of hypoglycemia and is weight neutral. The addition of vildagliptin to metformin improves glucose control and significantly reduces gastrointestinal adverse events, particularly in patients inadequately controlled with metformin monotherapy. Its long-term advantages include preservation of β-cell function, reduction in total cholesterol, decrease in fasting lipolysis in adipose tissue, and triglyceride storage in non-fat tissues. Vildagliptin is well tolerated with a low incidence of AEs, and it does not increase the risk of cardiovascular/cerebrovascular (CCV) events. It can be taken before or after meals, and has little drug interaction, thus it will be well accepted.

Differences in the glucose-lowering efficacy of dipeptidyl peptidase-4 inhibitors between Asians and non-Asians: a systematic review and meta-analysis

AIMS/HYPOTHESIS

The aim of this work was to compare the glucose-lowering efficacy of dipeptidyl peptidase-4 (DPP-4) inhibitors between Asian and non-Asian patients with type 2 diabetes.

METHODS

We searched MEDLINE, EMBASE, LILACS, CENTRAL, ClinicalTrials.gov and conference proceedings. Studies were eligible if they were randomised controlled trials with a treatment duration of at least 12 weeks, compared a DPP-4 inhibitor with a placebo as either monotherapy or oral combination therapy, had information on ethnicity and HbA1c values and were published or described in English. A systematic review and meta-analysis with a meta-regression analysis was conducted.

RESULTS

Among 809 potentially relevant studies, 55 trials were included. A meta-analysis revealed that DPP-4 inhibitors lowered HbA1c to a greater extent in studies with ≥50% Asian participants (weighted mean difference [WMD] -0.92%; 95% CI -1.03, -0.82) than in studies with <50% Asian participants (WMD -0.65%; 95% CI -0.69, -0.60). The between-group difference was -0.26% (95% CI -0.36, -0.17, p < 0.001). The baseline BMI significantly correlated with the HbA1c-lowering efficacy of DPP-4 inhibitors. The RR of achieving the goal of HbA1c <7.0% (53.0 mmol/mol) was higher in studies with ≥50% Asian participants (3.4 [95% CI 2.6, 4.7] vs 1.9 [95% CI 1.8, 2.0]). The fasting plasma glucose-lowering efficacy was higher with monotherapy in the Asian-dominant studies, but the postprandial glucose-lowering efficacy and changes in body weight were comparable between the two groups.

CONCLUSIONS/INTERPRETATION

DPP-4 inhibitors exhibit a better glucose-lowering efficacy in Asians than in other ethnic groups; this requires further investigation to understand the underlying mechanism, particularly in relation to BMI.

Predictive clinical parameters and glycemic efficacy of vildagliptin treatment in korean subjects with type 2 diabetes

BACKGROUND

The aims of this study are to investigate the glycemic efficacy and predictive parameters of vildagliptin therapy in Korean subjects with type 2 diabetes.

METHODS

In this retrospective study, we retrieved data for subjects who were on twice-daily 50 mg vildagliptin for at least 6 months, and classified the subjects into five treatment groups. In three of the groups, we added vildagliptin to their existing medication regimen; in the other two groups, we replaced one of their existing medications with vildagliptin. We then analyzed the changes in glucose parameters and clinical characteristics.

RESULTS

Ultimately, 327 subjects were analyzed in this study. Vildagliptin significantly improved hemoglobin A1c (HbA1c) levels over 6 months. The changes in HbA1c levels (ΔHbA1c) at month 6 were -2.24% (P=0.000), -0.77% (P=0.000), -0.80% (P=0.001), -0.61% (P=0.000), and -0.34% (P=0.025) for groups 1, 2, 3, 4, and 5, respectively, with significance. We also found significant decrements in fasting plasma glucose levels in groups 1, 2, 3, and 4 (P<0.05). Of the variables, initial HbA1c levels (P=0.032) and history of sulfonylurea use (P=0.026) were independently associated with responsiveness to vildagliptin treatment.

CONCLUSION

Vildagliptin was effective when it was used in subjects with poor glycemic control. It controlled fasting plasma glucose levels as well as sulfonylurea treatment in Korean type 2 diabetic subjects.

Efficacy of vildagliptin in combination with insulin in patients with type 2 diabetes and severe renal impairment

Background

The purpose of this study was to evaluate the efficacy of vildagliptin 50 mg once daily in patients with severe renal impairment (estimated glomerular filtration rate < 30 mL/min/1.73 m²) and longstanding type 2 diabetes not adequately controlled with insulin therapy, which is a difficult-to-treat population, with limited therapeutic options and a high susceptibility to hypoglycemia.

Methods

This was a post hoc subanalysis of data obtained during a previously described randomized, double-blind, parallel-group, 24-week study comparing the efficacy and safety of vildagliptin 50 mg once daily versus placebo in patients with type 2 diabetes and moderate or severe renal impairment. The present data derive from 178 patients with severe renal impairment (baseline estimated glomerular filtration rate approximately 21 mL/min/1.73 m², 100 randomized to vildagliptin, 78 randomized to placebo), all of whom were receiving insulin therapy (alone or in combination with an oral antidiabetic agent) for longstanding type 2 diabetes (mean approximately 19 years).

Results

With vildagliptin in combination with insulin, the adjusted mean change (AMΔ) in HbA_1c from baseline (7.7% ± 0.1%) was −0.9% ± 0.4% and the between-treatment difference (vildagliptin – placebo) was −0.6% ± 0.2% (P < 0.001). The percentage of patients achieving endpoint HbA_1c < 7.0% was significantly higher with vildagliptin than placebo (45.2% versus 22.8%, P = 0.008). When added to insulin, vildagliptin and placebo had comparable hypoglycemic profiles and did not cause weight gain. Both treatments were similarly well tolerated, with comparable incidences of adverse events, serious adverse events, and deaths.

Conclusion

When added to insulin therapy in patients with severe renal impairment and longstanding type 2 diabetes, vildagliptin 50 mg once daily was efficacious, eliciting HbA_1c reductions consistent with those previously reported for a patient population with much more recent onset of type 2 diabetes and normal renal function, and had a hypoglycemic profile comparable with placebo. Accordingly, vildagliptin is a suitable treatment option for patients with advanced type 2 diabetes and impaired renal function who require insulin therapy and present a serious therapeutic challenge in clinical practice.

Efficacy of vildagliptin on glucose fluctuation in Japanese type 2 diabetic patients with ongoing sulfonylurea based oral glycemic agent therapy

AIM

To investigate whether vildagliptin, one of the dipeptidylpeptide-4 (DDP-4) inhibitors, improves not only glycemic control but also glycemic fluctuation when added to ongoing sulfonylurea (SU) based oral hypoglycemic agents (OHA) therapy in patients with type 2 diabetes mellitus (T2DM).

METHODS

A total of 19 patients with T2DM were recruited from outpatients. Vildagliptin was initiated with a dose of 100mg per day in the patients who had inadequate glycemic control and glycemic fluctuation with ongoing SU based OHA therapy. Glycemic excursion was defined by seven-point self-monitoring blood glucose (SMBG) on three days at baseline and 12 weeks after vildagliptin-combined therapy, as well as HbA1c levels. M-value and J-index were calculated to evaluate glycemic excursion.

RESULTS

Addition of vildagliptin to ongoing SU based OHA therapy significantly decreased HbA1c values from 8.2 ± 3.8% at baseline to 7.3 ± 0.8% at 12-week. The average of blood glucose profiles was significant improved. As a result, M-value was significantly corrected from 20.9 ± 14.4 to 12.2 ± 13.5 and J-index from 55.1 ± 25.5 to 39.1 ± 19.8.

CONCLUSIONS

Vildagliptin when added to ongoing SU based OHA therapy for 12 weeks significantly improved glycemic fluctuation as well as glycemic control in Japanese patients with T2DM.

Linagliptin monotherapy in type 2 diabetes patients for whom metformin is inappropriate: an 18-week randomized, double-blind, placebo-controlled phase III trial with a 34-week active-controlled extension

AIMS

To investigate the efficacy and safety of linagliptin, a dipeptidyl peptidase-4 inhibitor, in type 2 diabetes mellitus (T2DM) patients for whom metformin was inappropriate.

METHODS

This 1-year double-blind study (ClinicalTrials.gov, NCT00740051) enrolled T2DM patients with inadequate glycaemic control, treatment-naïve [glycated haemoglobin (HbA1c) 7.0-10.0%] or previously treated with one oral antidiabetes drug (HbA1c 6.5-9.0% before washout), ineligible for metformin because of contraindications (e.g. renal impairment) or previous intolerable side effects. Patients were randomized to monotherapy with linagliptin 5 mg once daily (n = 151) or placebo (n = 76) for 18 weeks, after which placebo patients switched to glimepiride 1-4 mg once daily and treatments continued for another 34 weeks. The primary endpoint was change from baseline in HbA1c after 18 weeks (full-analysis set, last observation carried forward).

RESULTS

At week 18, adjusted mean difference in change from baseline HbA1c (8.1%) was -0.60% (95% confidence interval -0.88, -0.32; p < 0.0001) (-0.39% with linagliptin, +0.21% with placebo). At week 52, mean HbA1c was decreased from baseline in both groups [linagliptin: -0.44%; placebo/glimepiride: -0.72% (observed cases)]. Adverse events occurred in 40.4 and 48.7% of linagliptin and placebo patients, respectively, during the initial 18 weeks. During the 34-week extension, patients receiving linagliptin experienced less hypoglycaemia (2.2% vs. 7.8%) and no weight gain (mean change from baseline of -0.2 and +1.3 kg, respectively) compared with glimepiride patients.

CONCLUSIONS

In T2DM patients for whom metformin was inappropriate, linagliptin improved glycaemic control and was well tolerated, with less hypoglycaemia and relative weight loss compared with glimepiride.

Longer term safety of dipeptidyl peptidase-4 inhibitors in patients with type 2 diabetes mellitus: systematic review and meta-analysis

Dipeptidyl peptidase-4 (DPP-4) inhibitors are oral antidiabetic agents that hold the potential of slowing the progress of type 2 diabetes mellitus. Their long-term safety is still a subject of debate. A systematic review of randomized, controlled trials was undertaken to comprehensively profile the safety of chronic treatment of type 2 diabetes mellitus with DPP-4 inhibitors. We searched data sources including MEDLINE, CENTRAL, publishers' and manufacturers' databases. Eligible trials were double-blind, randomized, placebo or active-controlled trials with ≥18 weeks duration in patients with type 2 diabetes reporting safety outcomes. Meta-analysis was performed separately for trials in which the control group received placebo (44 studies), another gliptin (3 studies) and any other antidiabetic drug (20 studies). Risk ratios with 95% confidence intervals were computed using a Mantel-Haenszel fixed-effect model for general safety outcomes, hypoglycaemia and adverse events by system organ class. Of 307 publications retrieved, 67 randomized, controlled trials met the eligibility criteria and were included in this review (4 alogliptin, 8 linagliptin, 8 saxagliptin, 20 sitagliptin, and 27 vildagliptin trials). Adverse events with gliptin treatment were at placebo level (relative risk (RR) 1.02 [0.99, 1.04]). No increased risk of infections was detectable (RR 0.98 [0.93, 1.05] compared to placebo and 1.02 [0.97, 1.07] compared to other antidiabetic drugs). Asthenia (RR 1.57 [1.09, 2.27]) as well as cardiac (RR 1.37 [1.00, 1.89]) and vascular disorders (RR 1.74 [1.05, 2.86] for linagliptin) emerged as adverse events associated with DPP-4 inhibitor treatment. The risk of hypoglycaemia was low with DPP-4 inhibitor treatment (RR 0.92 [0.74, 1.15] compared to placebo, RR 0.20 [0.17, 0.24] compared to sulphonylureas) in the absence of sulphonylurea or insulin co-therapy, but significantly elevated for combination therapy of sulphonylurea or insulin with sitagliptin or linagliptin (RR 1.86 [1.46, 2.37] compared to placebo). A large body of data supports the long-term safety of gliptin treatment and refutes an increased risk of infections. Further research is needed to clarify a possible link to asthenia, cardiac and vascular events. For combination therapy with insulin or insulin secretagogues, a careful choice of the agent used may limit the risk of hypoglycaemia.

Efficacy and safety of dipeptidyl peptidase-4 inhibitors in type 2 diabetes: meta-analysis

BACKGROUND

An up-to-date assessment of dipeptidyl peptidase-4 (DPP-4) inhibitors is needed to include newly available data.

OBJECTIVE

To assess the efficacy and safety of DPP-4 inhibitors, including sitagliptin, saxagliptin, vildagliptin, and linagliptin, in type 2 diabetes.

METHODS

We conducted a search of MEDLINE for randomized controlled trials (RCTs) of DPP-4 inhibitors in type 2 diabetes through November 2011, using the key terms sitagliptin, saxagliptin, vildagliptin, and linagliptin. We also searched for completed, but unpublished, trials at relevant web sites. RCTs were selected for meta-analysis if they (1) compared DPP-4 inhibitors with placebo or an antihyperglycemic agent; (2) had study duration of 12 or more weeks; (3) had 1 or more baseline and posttreatment efficacy and/or safety outcome; and (4) were published in English.

RESULTS

In 62 evaluated articles, DPP-4 inhibitors lowered hemoglobin A(1c) (A1C) significantly more than placebo (weighted mean difference [WMD] -0.76%; 95% CI -0.83 to -0.68); however, heterogeneity was substantial (I(2) = 82%). Exclusion of Japanese trials (n = 7) resulted in a reduction of heterogeneity (I(2) = 59%). In the non-Japanese RCTs (n = 55), DPP-4 inhibitors were associated with a reduction in A1C (WMD -0.65%; 95% CI -0.71 to -0.60) but higher risk of hypoglycemia (odds ratio [OR] 1.30; 95% CI 1.00 to 1.68) compared to placebo. The 7 Japanese-specific RCTs showed a greater reduction in A1C (WMD -1.67%; 95% CI -1.89 to -1.44) and a nonsignificant increase in risk of hypoglycemia (OR 1.41; 95% CI 0.51 to 3.88) with DPP-4 inhibitors versus placebo. When comparing DPP-4 inhibitors to active comparators, the I(2) was still high after deleting Japanese studies. In these 17 active comparator trials, there was no significant difference in A1C reduction (WMD 0.04%; 95% CI -0.09 to 0.16) or risk of hypoglycemia (OR 0.60; 95% CI 0.22 to 1.61) for DPP-4 inhibitors compared to other antihyperglycemics. There were similar odds of any or serious adverse events with DPP-4 inhibitors compared to placebo, but a decreased risk compared to other antihyperglycemics.

CONCLUSIONS

DPP-4 inhibitors were associated with a reduction in A1C with comparable safety profiles compared to placebo, but no significant difference in A1C compared to other hyperglycemics. Differences in efficacy and safety were observed between Japanese and non-Japanese patients.

Efficacy and safety of switching from the DPP-4 inhibitor sitagliptin to the human GLP-1 analog liraglutide after 52 weeks in metformin-treated patients with type 2 diabetes: a randomized, open-label trial

OBJECTIVE

To assess the efficacy and safety of switching from sitagliptin to liraglutide in metformin-treated adults with type 2 diabetes.

RESEARCH DESIGN AND METHODS

In an open-label trial, participants randomized to receive either liraglutide (1.2 or 1.8 mg/day) or sitagliptin (100 mg/day), each added to metformin, continued treatment for 52 weeks. In a 26-week extension, sitagliptin-treated participants were randomly allocated to receive instead liraglutide at either 1.2 or 1.8 mg/day, while participants originally randomized to receive liraglutide continued unchanged.

RESULTS

Although 52 weeks of sitagliptin changed glycosylated hemoglobin (HbA(1c)) by -0.9% from baseline, additional decreases occurred after switching to liraglutide (1.2 mg/day, -0.2%, P = 0.006; 1.8 mg/day, -0.5%, P = 0.0001). Conversion to liraglutide was associated with reductions in fasting plasma glucose (FPG) (1.2 mg/day, -0.8 mmol/L, P = 0.0004; 1.8 mg/day, -1.4 mmol/L, P < 0.0001) and body weight (1.2 mg/day, -1.6 kg; 1.8 mg/day, -2.5 kg; both P < 0.0001) and with an increased proportion of patients reaching HbA(1c) <7% (from ∼30% to ∼50%). Overall treatment satisfaction, assessed by the Diabetes Treatment Satisfaction Questionnaire, improved after switching to liraglutide (pooled 1.2 and 1.8 mg/day, 1.3; P = 0.0189). After switching, mostly transient nausea occurred in 21% of participants, and minor hypoglycemia remained low (3-4% of participants). Continuing liraglutide treatment at 1.2 mg/day and 1.8 mg/day for 78 weeks reduced HbA(1c) (baseline 8.3 and 8.4%, respectively) by -0.9 and -1.3%, respectively; FPG by -1.3 and -1.7 mmol/L, respectively; and weight by -2.6 and -3.1 kg, respectively, with 9-10% of participants reporting minor hypoglycemia.

CONCLUSIONS

Glycemic control, weight, and treatment satisfaction improved after switching from sitagliptin to liraglutide, albeit with a transient increase in gastrointestinal reactions.

Effects of saxagliptin and sitagliptin on glycaemic control and pancreatic β-cell mass in a streptozotocin-induced mouse model of type 2 diabetes

AIMS

We examined the effects of the oral dipeptidyl peptidase-4 (DPP-4) inhibitor saxagliptin on glycaemic control and pancreatic β-cell mass and morphology in a mouse model of type 2 diabetes mellitus (T2DM).

METHODS

Male C57BL/6 mice (n = 12/group) aged 4 to 6 weeks and weighing >15 g received a high-fat diet throughout this 45-day study. After a 7-day handling period, baseline levels of plasma glucose, plasma insulin and glycated haemoglobin (HbA1c) were assessed. Animals were allocated to one of six groups: compound vehicle control, intraperitoneal streptozotocin (STZ, 50 mg/kg)-treated control and saxagliptin (10 mg/kg) or sitagliptin (10 mg/kg, positive control) initiated 7 days before or 1 day after STZ administration. Endpoints included changes in body weight, food and water consumption, glucose tolerance (approximately 3 weeks post-STZ), fasting glucose and HbA1c and immunohistochemical analyses of the pancreas.

RESULTS

Body weight, weight gain and food intake were reduced in STZ versus control mice. DPP-4 inhibitor treatment did not affect these changes, but the increase in water intake observed post-STZ administration was significantly attenuated with DPP-4 inhibitors whether initiated before or after STZ injury. Small but significant improvements in glycaemic control were observed with DPP-4 inhibitors versus the STZ control. Improved β-cell mass and morphology were observed with saxagliptin given pre- or post-STZ and sitagliptin given post-STZ.

CONCLUSIONS

Saxagliptin mitigated damage to β-cells and improved glycaemic control in this mouse model of T2DM.

Effects on lipid profile of dipeptidyl peptidase 4 inhibitors, pioglitazone, acarbose, and sulfonylureas: meta-analysis of placebo-controlled trials

INTRODUCTION

Lipid profile is an important determinant of cardiovascular risk in type 2 diabetes. It is well known that patients with type 2 diabetes are more likely to be dyslipidemic than the general population. Given the observed connection between glucose and lipid metabolism in patients with type 2 diabetes, it is conceivable that different glucose-lowering agents can have a varying impact on the lipid profile. When metformin monotherapy fails, other drugs can be added to achieve sufficient glycemic control. Available oral agents include pioglitazone, acarbose, dipeptidyl peptidase 4 (DPP-4) inhibitors, and insulin secretagogs. The present meta-analysis was designed to assess the effect of DPP-4 inhibitors, pioglitazone, insulin secretagogs, and acarbose on blood lipids when compared to placebo.

METHODS

An extensive search (any date up to November 1, 2011) was performed for all trials performed on the following classes of drugs: gliptin, insulin secretagogs, pioglitazone, and acarbose. The following endpoints were considered: endpoint total, high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C) and triglycerides.

RESULTS

The difference in mean total cholesterol values at endpoint versus baseline was significantly higher in patients on pioglitazone, sulfonylureas, and DPP-4 inhibitor treatment (but not on acarbose) than those on placebo, demonstrating that treatment with these drugs (except acarbose) is associated with a significant reduction in total cholesterol. With respect to triglycerides, a significant reduction could be observed with acarbose, pioglitazone, and DPP-4 inhibitors, but not with sulfonylureas. HDL-C appeared to be increased by treatment with acarbose and pioglitazone, and decreased by sulfonylureas.

CONCLUSION

The present meta-analysis shows that available glucose-lowering drugs may have varying effects on the lipid profile. DPP-4 inhibitors, acarbose, and pioglitazone seem to have a more favorable effect on the lipid profile than sulfonylureas.

Glimepiride: evidence-based facts, trends, and observations (GIFTS). [corrected]

Type 2 diabetes mellitus is characterized by insulin resistance and progressive β cell failure; therefore, β cell secretagogues are useful for achieving sufficient glycemic control. Glimepiride is a second-generation sulfonylurea that stimulates pancreatic β cells to release insulin. Additionally, is has been shown to work via several extra pancreatic mechanisms. It is administered as monotherapy in patients with type 2 diabetes mellitus in whom glycemic control is not achieved by dietary and lifestyle modifications. It can also be combined with other antihyperglycemic agents, including metformin and insulin, in patients who are not adequately controlled by sulfonylureas alone. The effective dosage range is 1 to 8 mg/day; however, there is no significant difference between 4 and 8 mg/day, but it should be used with caution in the elderly and in patients with renal or hepatic disease. In clinical studies, glimepiride was generally associated with lower risk of hypoglycemia and less weight gain compared to other sulfonylureas. Glimepiride use may be safer in patients with cardiovascular disease because of its lack of detrimental effects on ischemic preconditioning. It is effective in reducing fasting plasma glucose, post-prandial glucose, and glycosylated hemoglobin levels and is a useful, cost-effective treatment option for managing type 2 diabetes mellitus.

Efficacy and tolerability of vildagliptin as add-on therapy to metformin in Chinese patients with type 2 diabetes mellitus

AIM

To investigate the efficacy and tolerability of vildagliptin as add-on therapy to metformin in Chinese patients with type 2 diabetes mellitus (T2DM) inadequately controlled with metformin.

METHODS

This was a 24-week, randomized, double-blind, placebo-controlled study. Patients with T2DM (N = 438) with haemoglobin A1c (HbA1c) of 7.0-10.0% and fasting plasma glucose (FPG) <15 mmol/l (<270 mg/dl) were randomized (1 : 1 : 1) to vildagliptin 50 mg bid, vildagliptin 50 mg qd or placebo in addition to metformin.

RESULTS

The treatment groups were well balanced at baseline [mean HbA1c, 8.0%, FPG, 8.8 mmol/l (158 mg/dl); body mass index, 25.5 kg/m(2) ]. The adjusted mean change (AMΔ) in HbA1c at endpoint was -1.05 ± 0.08%, -0.92 ± 0.08% and -0.54 ± 0.08% in patients receiving vildagliptin 50 mg bid, 50 mg qd and placebo, respectively. The between-treatment difference (vildagliptin 50 mg bid-placebo) was -0.51 ± 0.11%, p < 0.001. A greater proportion of vildagliptin-treated patients met at least one responder criterion (82.1 and 70.7%) compared to placebo-treated patients (60.4%). The AMΔ at endpoint for FPG with vildagliptin 50 mg bid, -0.95 mmol/l (-17.1 mg/dl); 50 mg qd, -0.84 mmol/l (-15.1 mg/dl) was significantly different compared with the placebo -0.26 mmol/l (-4.68 mg/dl) (p ≤ 0.001). Adverse events (AEs) were reported as 34.2, 36.5 and 37.5% for patients receiving vildagliptin 50 mg bid, 50 mg qd or placebo, respectively. Two patients in the vildagliptin 50 mg qd and one in the placebo group reported serious AEs, which were not considered to be related to the study drug; one incidence of hypoglycaemic event was reported in the vildagliptin 50 mg bid group.

CONCLUSION

Vildagliptin as add-on therapy to metformin improved glycaemic control and was well tolerated in Chinese patients who were inadequately controlled by metformin only.

Clinical pharmacokinetics and pharmacodynamics of vildagliptin

Vildagliptin is an orally active, potent and selective dipeptidyl peptidase-4 (DPP-4) inhibitor, shown to be effective and well tolerated in patients with type 2 diabetes mellitus (T2DM) as either monotherapy or in combination with other anti-diabetic agents. Vildagliptin possesses several desirable pharmacokinetic properties that contribute to its lower variability and low potential for drug interaction. Following oral administration, vildagliptin is rapidly and well absorbed with an absolute bioavailability of 85%. An approximately dose-proportional increase in exposure to vildagliptin over the dose range of 25-200 mg has been reported. Food does not have a clinically relevant impact on the pharmacokinetics of vildagliptin, and it can be taken without regard to food. Vildagliptin is minimally bound to plasma proteins (9.3%) and, on the basis of a volume of distribution of 71 L, it is considered to distribute extensively into extravascular spaces. Renal clearance of vildagliptin (13 L/h) accounts for 33% of the total body clearance after intravenous administration (41 L/h). The primary elimination pathway is hydrolysis by multiple tissues/organs. The DPP-4 enzyme contributes to the formation of the major hydrolysis metabolite, LAY151; therefore, vildagliptin is also a substrate of DPP-4. Vildagliptin has a low potential for drug interactions, as cytochrome P450 (CYP) enzymes are minimally (<1.6%) involved in the overall metabolism. Clinical pharmacokinetic studies have reported the lack of drug interaction with several drugs (metformin, pioglitazone, glyburide, simvastatin, amlodipine, valsartan, ramipril, digoxin and warfarin) that are likely to be frequently co-administered to patients with T2DM. In particular, vildagliptin does not affect the pharmacokinetics of pioglitazone, glyburide, warfarin and simvastatin; therefore, it is not expected to affect the pharmacokinetics of a drug that is a substrate for CYP2C8, CYP2C9 or CYP3A4. In the elderly, vildagliptin exposure increases by approximately 30%, which is considered to be mostly attributable to compromised renal function in the elderly population and is not considered to be clinically relevant. Vildagliptin has been demonstrated to be efficacious, safe and well tolerated in elderly patients with T2DM without dose adjustment. In subjects with varying degrees of renal impairment, vildagliptin exposure increases by approximately 2-fold; however, the increase in the exposure does not correlate with the severity of renal impairment. The lack of a clear correlation between the increased exposure and the severity of renal impairment is considered to be attributable to the fact that the kidneys contribute to both the excretion and the hydrolysis metabolism of vildagliptin. Hepatic impairment, gender, body mass index (BMI) and ethnicity do not have an influence on the pharmacokinetics of vildagliptin. These findings suggest that vildagliptin can be used in a diverse patient population without dose adjustment. Oral administration of vildagliptin to patients with T2DM completely inhibits DPP-4 activity at a variety of doses. The onset of DPP-4 inhibition is rapid, and the duration of DPP-4 inhibition is dose dependent. Vildagliptin is a potent inhibitor of the DPP-4 enzyme, with a concentration required to achieve 50% DPP-4 inhibition (IC(50)) of 4.5 nmol/L in patients with T2DM. Similar potency of DPP-4 inhibition by vildagliptin has been reported in different ethnic groups, indicating that ethnicity does not affect the pharmacodynamics of vildagliptin. Vildagliptin significantly increases the active glucagon-like peptide 1 (GLP-1) levels by approximately 2- to 3-fold and glucose-dependent insulinotropic polypeptide (GIP) levels by approximately 5-fold, and significantly suppresses the postprandial glucagon levels in response to a meal or following an oral glucose tolerance test (OGTT) in patients with T2DM. Vildagliptin significantly reduces both fasting and postprandial glucose levels over the dose range of 50-100 mg daily (administered either once daily or twice daily), and there are no substantial additional benefits of doses greater than 50 mg twice daily. The primary clinical dosing regimen is 50 mg twice daily as monotherapy or in combination with metformin. Vildagliptin increases the insulin levels following an OGTT and an intravenous glucose tolerance test (IVGTT), and the stimulation of insulin secretion is glucose dependent. Vildagliptin has been shown to improve beta-cell function on the basis of pharmacodynamic modelling taking the reduced glucose levels into account. The improvement of beta-cell function by vildagliptin has been confirmed after chronic treatment with vildagliptin for up to 2 years. Reduction of the endogenous glucose production appears to contribute to the glucose-lowering effects. Unlike the GLP-1 receptor agonists, vildagliptin does not affect gastric emptying, and this is consistent with the favourable gastrointestinal safety profile. Vildagliptin improves the sensitivity of the alpha cell to glucose in patients with T2DM by enhancing the alpha-cell responsiveness to both suppressive effects of hyperglycaemia and stimulatory effects of hypoglycaemia. Consistently, a lower incidence of hypoglycaemic events with vildagliptin is reported when it is used as either monotherapy or in combination with other anti-diabetic agents, such as metformin or insulin, as compared with a sulphonylurea. Numerous long-term clinical trials of up to 2 years have demonstrated that vildagliptin 50 mg once daily or twice daily is effective, safe and well tolerated in patients with T2DM as either monotherapy or in combination with a variety of other anti-diabetic agents.

Evidence to support the use of vildagliptin monotherapy in the treatment of type 2 diabetes mellitus

The efficacy and safety of the dipeptidyl peptidase-4 inhibitor, vildagliptin, as monotherapy have been widely confirmed in a large body of clinical studies of up to 2 years’ duration in various populations with type 2 diabetes mellitus. This paper reviews the data supporting the use of vildagliptin in monotherapy. Consideration based on baseline glycated hemoglobin levels and age is given to patient segments where metformin is not appropriate. In addition, although prediabetes is not an indication, this manuscript briefly reviews some of the existing data showing that the mechanisms at work in diabetic populations are active in patients currently classified as prediabetic, with impaired glucose tolerance or impaired fasting glucose. Finally, the rationale for vildagliptin dosing frequency in monotherapy is discussed. In summary, this review aims to define where in community practice the use of vildagliptin as monotherapy is most desirable, focusing on segments of the population with type 2 diabetes mellitus that might receive the greatest benefit from vildagliptin in the management of their disease.

Alogliptin benzoate for the treatment of type 2 diabetes

INTRODUCTION

Alogliptin is a highly selective inhibitor of the enzyme dipeptidyl peptidase-4 (DPP-4). It is one of several agents of this class now available for treatment of type 2 diabetes.

AREAS COVERED

This review is based upon a PubMed search and personal experience with alogliptin. The pharmacokinetics and pharmacodynamics of alogliptin are reviewed. The glucose-lowering effect of this agent is discussed as monotherapy and in combination with metformin, sulfonylurea, piogilitazone and insulin. The potential adverse effects of alogliptin are summarized. Alogliptin is compared with the other available DPP-4 inhibitors.

EXPERT OPINION

Alogliptin is an additional choice in the group of DPP-4 inhibitors. As a group, these agents have a relatively modest glucose-lowering effect, inferior to that of metformin, sulfonylureas, and insulin. They do not have the benefit of weight loss offered by the glucagon-like polypeptide (GLP)-1 agonists. The primary use of DPP-4 inhibitors is in combination with other hypoglycemic agents, mainly metformin. Their principal advantage is a low incidence of hypoglycemia, making these agents desirable in patients such as the elderly and those with cardiac disease. A greater use of alogliptin and other DPP-4 inhibitors will occur if long-term studies show reduced cardiac events or long-term retention of insulin secretory capacity. The Examine Trial, a large study of alogliptin in coronary disease patients, is now underway and could provide important supportive data.

Pharmacology of dipeptidyl peptidase-4 inhibitors: similarities and differences

The dipeptidyl peptidase (DPP)-4 inhibitors, which enhance glucose-dependent insulin secretion from pancreatic β cells by preventing DPP-4-mediated degradation of endogenously released incretin hormones, represent a new therapeutic approach to the management of type 2 diabetes mellitus. The 'first-in-class' DPP-4 inhibitor, sitagliptin, was approved in 2006; it was followed by vildagliptin (available in the EU and many other countries since 2007, although approval in the US is still pending), saxagliptin (in 2009), alogliptin (in 2010, presently only in Japan) and linagliptin, which was approved in the US in May 2011 and is undergoing regulatory review in Japan and the EU. As the number of DPP-4 inhibitors on the market increases, potential differences among the different members of the class become important when deciding which agent is best suited for an individual patient. The aim of this review is to provide a comprehensive and updated comparison of the pharmacodynamic and pharmacokinetic properties of DPP-4 inhibitors, and to pinpoint pharmacological differences of potential interest for their use in therapy. Despite their common mechanism of action, these agents show significant structural heterogeneity that could translate into different pharmacological properties. At the pharmacokinetic level, DPP-4 inhibitors have important differences, including half-life, systemic exposure, bioavailability, protein binding, metabolism, presence of active metabolites and excretion routes. These differences could be relevant, especially in patients with renal or hepatic impairment, and when considering combination therapy. At the pharmacodynamic level, the data available so far indicate a similar glucose-lowering efficacy of DPP-4 inhibitors, either as monotherapy or in combination with other hypoglycaemic drugs, a similar weight-neutral effect, and a comparable safety and tolerability profile. Data on nonglycaemic parameters are scant at present and do not allow a comparison among DPP-4 inhibitors. Several phase III trials of DPP-4 inhibitors are currently ongoing; these trials, along with post-marketing surveillance data, will hopefully increase our knowledge about the long-term efficacy and safety of DPP-4 inhibitor therapy, the effect on pancreatic cell function and peripheral glucose metabolism, and the effect on cardiovascular outcomes in patients with type 2 diabetes.

DPP-4 inhibitors and lipids: systematic review and meta-analysis

INTRODUCTION

Lipid profile is an important determinant of cardiovascular risk in type 2 diabetic patients. Available glucose-lowering agents can affect lipid levels. Dipeptidyl peptidase-4 (DPP-4) inhibitors have been reported to reduce total cholesterol, but results are inconsistent across trials. The present metaanalysis was designed to assess the effect of DPP-4 inhibitors on blood lipids, verifying possible differences across compounds of this class.

METHODS

An extensive search of Medline and the Cochrane Library (any date up to December 31, 2010, restricted to randomized clinical trials, published in English) was performed for all trials containing, in any field, the words "sitagliptin," "vildagliptin," "saxagliptin," "alogliptin," "linagliptin," and/or "dutogliptin." Completed but unpublished trials were identified through a search of the ClinicalTrials.gov website, using the same keywords as above. Differences in the endpoint levels and absolute or percent variations of lipids were assessed. A metaregression was performed on the trials specified above to assess the effect of putative moderators on the effect of DPP-4 inhibitors on plasma lipids, considering all drugs together and each one separately.

RESULTS

Although the number of trials of appropriate size and duration was high (n=53), only a small fraction of those (n=17) reported data on endpoint total, high-density lipoprotein, and low-density lipoprotein cholesterol, and triglyceride. The difference-in-means for endpoint versus baseline total cholesterol in patients on DPP-4 inhibitors treatment was significantly higher in comparison with controls, meaning that treatment with DPP-4 inhibitors is associated with a significant reduction in total cholesterol (-0.18 [-0.29; -0.06] mmol/L (-7.0 [-11.2; -2.50] mg/dL); P=0.002).

CONCLUSIONS

This meta-analysis suggests a possible beneficial effect of DPP-4 inhibitors on cholesterol, which, although small, could contribute to the reduction of cardiovascular risk.

The efficacy and safety of vildagliptin in patients with type 2 diabetes: a meta-analysis of randomized clinical trials

WHAT IS KNOWN AND OBJECTIVE

Dipeptidyl peptidase-4 (DPP-4) inhibitors are a relatively new class of drugs for the management of type 2 diabetes (T2DM). Vildagliptin is an oral DPP-4 inhibitor approved in more than 70 countries. The purpose of this meta-analysis is to provide an update on the clinical efficacy and safety of vildagliptin in patients with T2DM.

METHODS

A literature search identified 30 randomized controlled trials comparing vildagliptin with comparators (placebo or other hypoglycaemic agents). Meta-analyses were conducted for HbA1c, weight, fasting plasma glucose (FPG), hypoglycaemia and other adverse events. The outcomes of HbA1c, weight and FPG were analysed as weighted mean differences (WMD), and the number of ADRs events as relative risks (RR).

RESULTS

Compared with placebo, vildagliptin lowered HbA1c {WMD, -0·77% [95% confidence interval (CI), -0·96% to -0·58%] for 100 mg/day of vildagliptin and -0·58% [95% CI, -0·72% to -0·44%] for 50 mg/day of vildagliptin}. The effect was non-inferior to thiazolidinediones, sulfonylureas and α-glycosidase inhibitors, but inferior to metformin. Compared with placebo, treatment with 50 mg/day of vildagliptin caused neutral weight changes, while 100 mg/day of vildagliptin resulted in slight weight gain [0·95 kg (95% CI, 0·73-1·17 kg)]. In addition, compared to comparators, vildagliptin was not associated with an increase in overall risk for any adverse events [RR, 0·97 (95% CI, 0·94-0·99)]. The incidence of hypoglycaemia was low with vildagliptin, and the risk with vildagliptin was not significantly different from the comparators [0·85 (95% CI, 0·49-1·47)]. The use of vildagliptin did not display any increased risks of infection [1·03 (95% CI, 0·94-1·13) for nasopharyngitis and 1·07 (95% CI, 0·90-1·27) for upper respiratory tract infection].

WHAT IS NEW AND CONCLUSION

Vildagliptin is effective in glycaemic control with a low risk of hypoglycaemia and other adverse reactions. This may have an important impact on patient adherence to this medication.

The role of incretin therapy at different stages of diabetes

The pathogenetic mechanisms causing type 2 diabetes are complex, and include a significant reduction of the incretin effect. In patients with type 2 diabetes, GLP-1 secretion may be impaired, while GIP secretion seems unaffected. In contrast, the insulinotropic activity of GIP is severely altered, whereas that of GLP-1 is maintained to a great extent. Better understanding of the role of incretin hormones in glucose homeostasis has led to the development of incretin-based therapies that complement and offer important advantages over previously used agents. Incretin-based agents have significant glucose-lowering effects, promote weight loss (or are weight-neutral), inhibit glucagon secretion while maintaining counter-regulatory mechanisms, exhibit cardiovascular benefits, and protect β-cells while possessing a low risk profile. At present, incretin-based therapies are most widely used as add on to metformin to provide sufficient glycemic control after metformin failure. However, they are also recommended as monotherapy early in the disease course, and later in triple combination. These agents may also be a promising therapeutic tool in prediabetic subjects. Therefore, a therapeutic algorithm is needed for their optimal application at different stages of diabetes, as suggested in this article.

Tolerability of dipeptidyl peptidase-4 inhibitors: a review

BACKGROUND

Oral glucose-lowering agents are used to treat patients with type 2 diabetes mellitus (T2DM). Most patients require multiple agents to maintain glycemic targets. Dipeptidyl peptidase-4 (DPP-4) inhibitors are administered as monotherapy and in combination therapy for the treatment of T2DM.

OBJECTIVE

The aim of this article was to provide a thorough review of published tolerability data on 5 DPP-4 inhibitors.

METHODS

PubMed and Web of Science were searched for English-language clinical trials published from January 2000 to June 2001, using the following key words: dipeptidyl peptidase-4 inhibitor, vildagliptin, alogliptin, sitagliptin, saxagliptin, linagliptin, safety, tolerability, efficacy, effect, AE, and adverse effect. Studies were considered for inclusion if they were randomized, double-blind trials performed in patients ≥18 years of age with T2DM and with a hemoglobin A(1c) of ≥6.5%; included ≥1 arm that received monotherapy with DPP-4; and reported adverse events (AEs). Studies in patients with a history of type 1 or secondary forms of diabetes, significant diabetic complications or cardiovascular disease within the 6 months before the start of the study, hepatic disease or abnormalities, and/or renal abnormalities were excluded.

RESULTS

A total of 45 clinical trials, 5 pharmacokinetic studies, and 28 meta-analyses or reviews were included. The duration of studies ranged from 7 days to 104 weeks. The most commonly reported AEs were nasopharyngitis, upper respiratory infections, all-cause infections, headache, gastrointestinal symptoms, and musculoskeletal pain. Based on the findings from the studies, the DPP-4 inhibitors had minimal impact on weight and were not associated with an increased risk for hypoglycemia relative to placebo. Rates of nasopharyngitis were higher with the DDP-4 inhibitors than with placebo. Pancreatitis was reported at lower rates with the DPP-4 inhibitors compared with other oral antihyperglycemic agents. Cardiovascular events were limited, and postmarketing studies are ongoing.

CONCLUSIONS

The tolerability of DPP-4 inhibitors is supported by published clinical trials. The rates of weight gain, gastrointestinal AEs, and hypoglycemia were minimal with the DPP-4 inhibitors studied.

Comparison of vildagliptin-metformin and glimepiride-metformin treatments in type 2 diabetic patients

BACKGROUND

The present study investigated the efficacy and safety of vildagliptin-metformin treatment compared to those of glimepiride-metformin treatment for type 2 diabetes.

METHODS

In a randomized, open-label, comparative study, 106 patients with type 2 diabetes were enrolled. The primary endpoint was a reduction in HbA1c from baseline and secondary endpoints included fasting plasma glucose (FPG) or 2-hour postprandial glucose (2h-PPG) reduction from baseline, as well as HbA1c responder rate and HbA1c reduction according to baseline HbA1c category.

RESULTS

Comparable HbA1c reduction was observed with a mean±standard deviation change from baseline to the 32-week endpoint of -0.94±1.15% in the vildagliptin group and -1.00±1.32% in the glimepiride group. A similar reduction in 2h-PPG (vildagliptin group 3.53±4.11 mmol/L vs. the glimepiride group 3.72±4.17 mmol/L) was demonstrated, and the decrements in FPG (vildagliptin group 1.54±2.41 mmol/L vs. glimepiride group 2.16±2.51 mmol/L) were not different between groups. The proportion of patients who achieved an HbA1c less than 7% at week 32 was 50.1% in the vildagliptin group and 56.0% in the glimepiride group. An average body weight gain of 2.53±1.21 kg in the glimepiride group was observed in contrast with the 0.23±0.69 kg weight gain noted in the vildagliptin group. A 10-fold lower incidence of hypoglycemia was demonstrated in the vildagliptin group, in addition to an absence of severe hypoglycemia.

CONCLUSION

Vildagliptin-metformin treatment provided blood glucose control efficacy comparable to that of glimepiride-metformin treatment and resulted in better adverse event profiles with lower risks of hypoglycemia and weight gain.

Safety and efficacy of vildagliptin versus placebo in patients with type 2 diabetes and moderate or severe renal impairment: a prospective 24-week randomized placebo-controlled trial

AIM

Assess safety/tolerability and efficacy of the DPP-4 inhibitor vildagliptin in 515 patients with type 2 diabetes mellitus (T2DM) and moderate or severe renal impairment (RI).

METHODS

Double-blind, randomized, parallel-group, placebo-controlled, 24-week clinical trial assessing safety and efficacy of vildagliptin (50 mg qd) added to current antidiabetic therapy, in patients with T2DM and moderate or severe RI (GFR ≥ 30 to <50 or <30 ml/min/1.73 m(2) ).

RESULTS

The study population comprised of 165 and 129 patients with moderate RI and 124 and 97 patients with severe RI randomized to vildagliptin and placebo, respectively, with most patients receiving background insulin therapy (68 and 81% for moderate and severe RI, respectively). After 24 weeks, the between-treatment difference in the adjusted mean change in A1C was -0.5 ± 0.1% (p < 0.0001) in moderate RI (baseline A1C = 7.9%) and -0.6 ± 0.1% (p < 0.0001) in severe RI (baseline A1C = 7.7%). In patients with moderate RI, similar proportions of those receiving vildagliptin or placebo experienced any AE (68 vs. 73%), any SAE (9 vs. 9%), any AE leading to discontinuation (3 vs. 5%) or death (1 vs. 1%). This was also true for patients with severe RI: AEs (73 vs. 74%), SAEs (19 vs. 21%), AEs leading to discontinuation (9 vs. 6%) and death (2 vs. 4%).

CONCLUSIONS

In this 24-week study of 515 patients with T2DM and moderate or severe RI, vildagliptin added to ongoing antidiabetic therapy had a safety profile similar to placebo. Further, relative to placebo, vildagliptin elicited a statistically and clinically significant decrease in A1C in patients with moderate or severe RI.

Dipeptidyl peptidase-4 inhibitors and HbA1c target of <7% in type 2 diabetes: meta-analysis of randomized controlled trials

AIM

We assessed the efficacy of dipeptidyl peptidase-4 (DPP-4) inhibitors vildagliptin, sitagliptin, saxagliptin and alogliptin to reach the haemoglobin HbA1c target of <7% in people with type 2 diabetes.

METHODS

We conducted an electronic search for randomized controlled trials (RCTs) involving DPP-4 inhibitors through September 2010. RCTs were included if they lasted at least 12 weeks, included 30 patients or more and reported the proportion of patients reaching the HbA1c target of <7%.

RESULTS

A total of 43 RCTs reporting 52 comparisons met the selection criteria, which included 19 101 study participants evaluated for the primary endpoint, 10 467 treated with a DPP-4 inhibitor and 8634 treated with placebo or a comparator drug. DPP-4 inhibitors showed a statistically significant reduction in HbA1c compared to placebo and approximately 40% of participants achieved the HbA1c goal of <7%: this was associated with weight neutrality and no greater hypoglycaemia. The reduction of the HbA1c level and the rate of HbA1c goal attainment was not different from comparator drugs, with similar hypoglycaemia, and different effect on weight owing to the nature of comparator (metformin, sulfonylurea or glitazones). Baseline HbA1c was the best predictor for achievement of A1C target (overall weighted r(2) value = 0.410, p < 0.001).

CONCLUSIONS

A greater proportion of type 2 diabetic patients can achieve the HbA1c goal <7% with DPP-4 inhibitors compared to placebo, with no weight gain, and no hypoglycaemic risk when used alone; DPP-4 inhibitors were not different from comparator drugs.

Minimizing the risk of hypoglycemia with vildagliptin: Clinical experience, mechanistic basis, and importance in type 2 diabetes management

Even if the true incidence of hypoglycemia in type 2 diabetes mellitus (T2DM) remains difficult to estimate, with highly variable rates reported in the literature, it is likely more common than previously thought. While most hypoglycemic episodes in T2DM are considered "mild," they still have a substantial clinical impact. Severe hypoglycemia also exists in T2DM, with recent landmark studies prompting much debate about the potential role of severe hypoglycemia in cardiovascular morbidity and mortality, even though there is currently no definitive evidence for causality. The challenge in the treatment of T2DM remains the achievement of optimal glycemic control to lower the risk for long-term complications while avoiding hypoglycemia. Successful treatment strategies should therefore include careful selection of therapies to prevent hypoglycemia, starting early in the disease management process, in order to best preserve counterregulation. The dipeptidyl peptidase-4 inhibitor, vildagliptin, is a good treatment option to minimize the risk of hypoglycemia over time, while maintaining good glucose control. Extensive clinical experience is available for vildagliptin, with data published for all stages of the condition and with the low hypoglycemic potential stemming from a solid mechanistic basis.

Therapy in the early stage: incretins

The complex pathological mechanisms responsible for development of type 2 diabetes are not fully addressed by conventional drugs, which are also associated with inconvenient side effects such as weight gain or hypoglycemia. Two types of incretin-based therapies are now in use: incretin mimetics (glucagon-like peptide-1 [GLP-1] receptor agonists that bind specific receptors and mimic the action of natural GLP-1) and incretin enhancers (inhibitors of the enzyme that degrade the incretin hormones and thus prolong their activity). Both offer important advantages over previous agents. In addition to the proven glucose-lowering efficacy, they promote weight loss (or are weight neutral) by slowing gastric emptying and inducing satiety, inhibit glucagon secretion with maintenance of counterregulatory mechanisms, and exhibit cardiovascular benefits, while having a low risk profile. Importantly, short-term studies have shown that incretins/incretin-based therapies protect β-cells (by enhancing cell proliferation and differentiation and inhibiting apoptosis) and stimulate their function (by recruiting β-cells to the secretory process and increasing insulin biosynthesis/secretion). These therapies have the opportunity to interfere with the disease progression if used as an early intervention, when enough β-cell mass/function can still be preserved or restored.

Predictors of response to dipeptidyl peptidase-4 inhibitors: evidence from randomized clinical trials

AIM

Dipeptidyl peptidase-4 (DPP-4) inhibitors are used in the treatment of type 2 diabetes. Available sub-group analysis of clinical trials does not allow a clear identification of predictors of therapeutic response to these drugs. The aim of this study is the assessment of predictors of response to DPP-4 inhibitors.

MATERIALS AND METHODS

A meta-analysis was performed, exploring correlation between 24-week effects on HbA(1c) of maximal doses of DPP-4 inhibitors, compared either with placebo or with other active drugs, matches to baseline characteristics of patients enrolled in 63 randomized clinical trials, either published or unpublished but disclosed on different websites were studied.

RESULTS

DPP-4 inhibitors significantly reduce HbA(1c) at 24 weeks [by 0.6 (0.5-0.7)%] when compared with placebo; no difference in HbA(1c) was observed in comparisons with thiazolidinediones and α-glucosidase inhibitors, whereas sulfonylureas and metformin produced a greater reduction of HbA(1c) , at least in the short term. DPP-4 inhibitors produced a smaller weight gain than thiazolidinediones, and showed a lower hypoglycaemia risk than sulfonylureas. The placebo-subtracted effect of DPP-4 inhibitors on HbA(1c) was greater in older patients and in those with lower fasting plasma glucose at baseline. Similar results were obtained in comparisons with thiazolidinediones and metformin.

CONCLUSIONS

Although drugs for type 2 diabetes are studied in heterogeneous samples of patients, their efficacy can be predicted by some clinical parameters. DPP-4 inhibitors appear to be more effective in older patients with mild/moderate fasting hyperglycaemia. These data could be useful for a better definition of the profile of patients who are likely to benefit most from these drugs.

Vildagliptin: a review of its use in type 2 diabetes mellitus

Vildagliptin (Galvus®, Jalra®, Xiliarx®) is an orally administered dipeptidyl peptidase-4 (DPP-4) inhibitor. In patients with type 2 diabetes mellitus, vildagliptin 50 mg twice daily is indicated for use in combination with metformin or a thiazolidinedione, and vildagliptin 50 mg once daily is indicated for use in combination with a sulfonylurea. A fixed-dose combination of vildagliptin/metformin (Eucreas®, Icandra®, Zomarist®) is also available. This article reviews the clinical efficacy and tolerability of vildagliptin in patients with type 2 diabetes, as well as summarizing its pharmacological properties. The efficacy of monotherapy or combination therapy with oral vildagliptin in patients with type 2 diabetes has been examined in randomized, double-blind, multicentre trials. Monotherapy with vildagliptin 50 mg once or twice daily reduced glycosylated haemoglobin (HbA(1c)) from baseline to a significantly greater extent than placebo, according to the results of 12- to 52-week trials in patients with type 2 diabetes. In terms of the reduction from baseline in HbA(1c) seen in active comparator trials of 12-104 weeks' duration, the noninferiority of vildagliptin 50 mg twice daily was established versus acarbose or rosiglitazone, the noninferiority of vildagliptin 100 mg once daily (an off-label dosage) versus metformin was established in elderly patients and vildagliptin 50 mg twice daily was more effective than voglibose; however, the noninferiority of vildagliptin 50 mg twice daily versus metformin or gliclazide was not established in two other trials. Combination therapy with vildagliptin 50 mg twice daily plus metformin improved HbA(1c) to a significantly greater extent than monotherapy with metformin and/or vildagliptin alone in patients with type 2 diabetes whose disease was inadequately controlled by metformin monotherapy or who were treatment naive, according to the results of 12- or 24-week trials. In addition, vildagliptin 50 mg twice daily plus metformin demonstrated noninferiority to pioglitazone plus metformin, glimepiride plus metformin or gliclazide plus metformin in terms of the change from baseline in HbA(1c) after 24 or 52 weeks' therapy in patients with inadequately controlled type 2 diabetes. The addition of vildagliptin 50 mg twice daily to pioglitazone or vildagliptin 50 mg once daily to glimepiride improved HbA(1c) to a significantly greater extent than a thiazolidinedione or glimepiride alone in patients with type 2 diabetes whose disease was inadequately controlled, according to the results of 24-week trials. Oral vildagliptin 50 mg once or twice daily was generally well tolerated in patients with type 2 diabetes. In particular, vildagliptin was associated with a low risk of hypoglycaemia and was weight neutral. Increases in transaminase levels were sometimes observed with a vildagliptin dosage of 100 mg once daily in clinical trials, and liver function should be monitored in patients receiving vildagliptin. However, meta-analyses of clinical trial data suggested that vildagliptin 50 mg once or twice daily was not associated with an increased risk of hepatic adverse events, transaminase elevations ≥3 × the upper limit of normal, pancreatitis, cardiovascular or cerebrovascular events, infections or skin-related toxicity. In conclusion, vildagliptin is an important option for use in combination with metformin, a sulfonylurea or a thiazolidinedione in patients with type 2 diabetes who require combination therapy.

Clinical evidence and mechanistic basis for vildagliptin's action when added to metformin

Several new oral antidiabetic agents, known as 'gliptins' or 'enzyme dipeptidyl peptidase-IV (DPP-4) inhibitors', have been developed for the treatment of type 2 diabetes and a key clinical use of the gliptins is in combination with metformin. There are important differences in the kinetics of the interaction of different gliptins with the catalytic site of DPP-4, which may lead to varying pharmacokinetics, pharmacodynamics and dosing regimens. Therefore, individual gliptins need to be characterized and here we discuss the extensively studied DPP-4 inhibitor vildagliptin, which has binding characteristics that ensure inhibition of the enzyme beyond the presence of detectable drug levels in plasma. As vildagliptin has been used most often at doses of 50 mg once or twice daily, in combination with metformin, this review focuses on these dose regimens. All clinical trials employing vildagliptin (50 mg once or twice daily) as an add-on therapy to metformin (identified by MEDLINE search using keywords vildagliptin and metformin or known by authors to be in press) are reviewed, as is current knowledge of the mechanism of action of vildagliptin. Vildagliptin added to a stable dose of metformin elicits a dose-related decrease in both HbA1c and fasting plasma glucose. The additional efficacy seen with 50 mg twice daily [ΔHbA1c ∼- 1.1% (-12.1 mmol/mol)] relative to 50 mg once daily [ΔHbA1c ∼- 0.7% (-7.7 mmol/mol)] is attributable to an overnight effect of the evening dose of vildagliptin, with prolonged DPP-4 inhibition and elevated fasting levels of the intact and insulinotropic form of glucagon-like peptide-1 (GLP-1). Vildagliptin's therapeutic actions are primarily mediated by GLP-1 and metformin enhances vildagliptin's effect to raise plasma levels of intact GLP-1. Vildagliptin is weight-neutral and has a very low hypoglycaemic potential, explained by its remarkable ability to enhance both α-cell and β-cell sensitivity to glucose. Therefore, vildagliptin offers a clinically important outcome when added to metformin with a twice daily dose regimen, taking advantage of its tight binding and slow dissociation characteristics that lead to a sustained overnight effect.

Assessing the general safety and tolerability of vildagliptin: value of pooled analyses from a large safety database versus evaluation of individual studies

Aim:

Analyzing safety aspects of a drug from individual studies can lead to difficult-to-interpret results. The aim of this paper is therefore to assess the general safety and tolerability, including incidences of the most common adverse events (AEs), of vildagliptin based on a large pooled database of Phase II and III clinical trials.

Methods:

Safety data were pooled from 38 studies of ≥12 to ≥104 weeks’ duration. AE profiles of vildagliptin (50 mg bid; N = 6116) were evaluated relative to a pool of comparators (placebo and active comparators; N = 6210). Absolute incidence rates were calculated for all AEs, serious AEs (SAEs), discontinuations due to AEs, and deaths.

Results:

Overall AEs, SAEs, discontinuations due to AEs, and deaths were all reported with a similar frequency in patients receiving vildagliptin (69.1%, 8.9%, 5.7%, and 0.4%, respectively) and patients receiving comparators (69.0%, 9.0%, 6.4%, and 0.4%, respectively), whereas drug-related AEs were seen with a lower frequency in vildagliptin-treated patients (15.7% vs 21.7% with comparators). The incidences of the most commonly reported specific AEs were also similar between vildagliptin and comparators, except for increased incidences of hypoglycemia, tremor, and hyperhidrosis in the comparator group related to the use of sulfonylureas.

Conclusions:

The present pooled analysis shows that vildagliptin was overall well tolerated in clinical trials of up to >2 years in duration. The data further emphasize the value of a pooled analysis from a large safety database versus assessing safety and tolerability from individual studies.

Clinical experience with vildagliptin in the management of type 2 diabetes in a patient population ≥75 years: a pooled analysis from a database of clinical trials

AIM

To report the experience with vildagliptin in a patient population with type 2 diabetes mellitus (T2DM) ≥75 years.

METHODS

Efficacy data from seven monotherapy and three add-on therapy to metformin studies, respectively, of ≥24 weeks duration were pooled; effects of 24 weeks of treatment with vildagliptin (50 mg bid) in patients ≥75 years were assessed in these two pooled datasets. Safety data were pooled from 38 studies of ≥12 to ≥104 weeks duration; adverse events (AEs) profiles of vildagliptin (50 mg bid) were evaluated relative to a pool of comparators; 301 patients ≥75 years were analysed. Data in patients <75 years are provided as a reference.

RESULTS

Mean age of the elderly population was 77 years. Changes in haemoglobin A1c (HbA1c) with vildagliptin in the patient group ≥75 years were -0.9% from a baseline of 8.3% in monotherapy (p < 0.0001) and -1.1% from a baseline of 8.5% in add-on therapy to metformin (p = 0.0004), and these reductions were similar to those seen in the younger patients. The corresponding weight changes in the elderly patients were -0.9 kg (p = 0.0277) and -0.2 kg [not significant (NS)], respectively, and no confirmed hypoglycaemic events, including no severe events, were reported. AEs, drug-related AEs, serious adverse events (SAEs) and deaths were reported with a lower frequency in older patients receiving vildagliptin than comparators [133.9 vs. 200.6, 14.5 vs. 21.8, 8.8 vs. 16.5 and 0.0 vs. 1.7 events per 100 subject year exposure (SYE), respectively], and the incidence of discontinuations due to AEs was similar in the two groups (7.2 vs. 7.5 events per 100 SYE, respectively). The safety profile of vildagliptin was overall similar in younger and older patients.

CONCLUSIONS

Vildagliptin was effective and well-tolerated in type 2 diabetic patients ≥75 years (mean age 77 years).

Multifactorial intervention in Type 2 diabetes: the promise of incretin-based therapies

Type 2 diabetes mellitus is increasing in prevalence at alarming rates. Concurrent with its expanding prevalence is the increase in the related risk of morbidity and mortality. Because diabetic patients are prone to cardiovascular disease, treatment strategies should address the cardiovascular risk factors, including blood pressure, lipids, and body weight, in addition to the glycemic aspects of the disease. Newer agents, such as glucagon-like peptide-1 (GLP-1) analogs and dipeptidyl peptidase-4 (DPP-4) inhibitors, have varying degrees of evidence to support their effects on body weight, blood pressure, and lipid levels, beyond glycated hemoglobin reduction. While GLP-1 agonists produce a weight loss, the DPP-4 inhibitors, conversely, appear to have a weight-neutral effect. Substantial evidence demonstrates that both medications produce modest reductions in systolic blood pressure and, in some cases, diastolic blood pressure, and reduce several markers of cardiovascular risk, including C-reactive protein. Moreover, GLP-1 influences endothelial function. The effect of the incretin hormones on serum lipids are either neutral or beneficial, with small, non-significant decreases in LDL cholesterol, increases in HDL cholesterol, and occasionally significant decreases in fasting triglyceride levels. Also, they have positive effects on hepatic steatosis. Although GLP-1 agonists and DPP-4 inhibitors are at present not appropriate for primary treatment of cardiovascular risks factors, the reduction of these parameters is evidently beneficial.

Incretins: clinical perspectives, relevance, and applications for the primary care physician in the treatment of patients with type 2 diabetes mellitus

The prevalence of type 2 diabetes mellitus (DM) is increasing substantially in the United States. Almost 24 million people have the disease, with most of these patients treated by primary care physicians. Optimal treatment of type 2 DM requires physicians to understand the pathophysiology of this disorder. Once the physiologic defects are determined, lifestyle interventions and glucose lowering medications can be prescribed to minimize the state of chronic hyperglycemia and to address the pathophysiologic defects associated with type 2 DM. Other metabolic abnormalities, including hyperlipidemia, hypertension, and oxidative stress, must also be addressed to reduce the patient's risk of cardiovascular disease. The incretin system plays a role in the pathogenesis of type 2 DM. Incretin-based therapies, including glucagon-like peptide 1 receptor agonists and dipeptidyl peptidase 4 inhibitors, have shown efficacy and safety in treating type 2 DM and have been reviewed in consensus treatment algorithms. This article provides an overview of the role of incretin-based therapies in the management of patients with type 2 DM and how primary care physicians can incorporate these agents into their practice.

Safety and tolerability of vildagliptin vs. thiazolidinedione as add-on to metformin in type 2 diabetic patients with and without mild renal impairment: a retrospective analysis of the GALIANT study

OBJECTIVE

This retrospective analysis assessed safety and tolerability of vildagliptin (Vilda) as an add-on to metformin in type 2 diabetes mellitus (T2DM) patients with normal renal function (GFR >80mL/min/1.73m(2)) and mild renal impairment (GFR: >50 to ≤80mL/min/1.73m(2)).

METHODS

Adverse events (AE) from this 12-week, randomized, open-label study comparing Vilda 100mg and thiazolidinediones (TZD) as an add-on therapy in patients with T2DM inadequately controlled (HbA(1c): 7-10%) on a stable dose of metformin (≥1000mg/day) were analyzed.

RESULTS

Of 2627 randomized patients, 1278 in the Vilda and 635 in the TZD groups had normal renal function; 463 in the Vilda and 230 in the TZD groups had mild renal impairment. Higher incidence of headache and rash was noted in both Vilda groups, whereas those with mild renal impairment receiving TZD experienced a higher incidence of peripheral edema and URI. Fewer patients in the Vilda group discontinued the study due to AEs compared to TZD group. Serious AEs were greater in TZD groups (normal: 2.4%; mild renal impairment: 3.0%) compared to Vilda groups (normal: 1.6%; mild renal impairment: 2.4%).

CONCLUSION

The safety profile of Vilda or TZD as an add-on to metformin was similar in patients with mild renal impairment and normal renal function.

A randomized, placebo-controlled, double-blind, prospective trial to evaluate the effect of vildagliptin in new-onset diabetes mellitus after kidney transplantation

Background

New-onset diabetes mellitus after transplantation (NODAT), a frequent and serious complication after transplantation, is associated with decreased graft and patient survival. Currently, it is diagnosed and treated primarily according to existing guidelines for type II diabetes. To date, only a few trials have studied antidiabetic drugs in patients with NODAT. Vildagliptin is a novel dipeptidyl peptidase-4 (DPP-4) inhibitor that improves pancreatic islet function by enhancing both α- and β-cell responsiveness to increased blood glucose. Experimental data show potential protective effects of DPP-4 inhibitors on islet function after exogenous stress stimuli including immunosuppressants. Therefore, the therapy of NODAT with this class of compounds seems attractive. At present, vildagliptin is used to treat type II diabetes as monotherapy or in combination with other antidiabetic drugs, since that it efficiently decreases glycated hemoglobin (HbA1c) values. Additionally, vildagliptin has been shown to be safe in patients with moderately impaired kidney function. This study will evaluate the safety and efficacy of vildagliptin monotherapy in renal transplant recipients with recently diagnosed NODAT.

Methods/Design

This study is a randomized, placebo-controlled, double-blind, prospective phase II trial. Using the results of routinely performed oral glucose tolerance tests (OGTT) in stable renal transplant patients at our center, we will recruit patients without a history of diabetes and a 2 h glucose value surpassing 200 mg/dl (11.1 mmol/l). They are randomized to receive either 50 mg vildagliptin or placebo once daily. A total of 32 patients with newly diagnosed NODAT will be included. The primary endpoint is the difference in the 2 h glucose value between baseline and the repeated OGTT performed 3 months after treatment start, compared between the vildagliptin- and the placebo-group. Secondary endpoints include changes in HbA1c and fasting plasma glucose (FPG). The safety of vildagliptin in renal transplant patients will be assessed by the number of symptomatic hypoglycemic episodes (glucose <72 mg/dl or 4 mmol/l), the number of adverse events, and possible medication-associated side-effects.

Discussion

NODAT is a severe complication after kidney transplantation. Few trials have assessed the safety and efficacy of antidiabetic drugs for these patients. The purpose of this study is to assess the safety and efficacy of vildagliptin in renal transplant patients with NODAT.

Trial Registration

ClinicalTrials.gov NCT00980356

Efficacy and tolerability of vildagliptin as an add-on to glimepiride in Japanese patients with Type 2 diabetes mellitus

AIM

To investigate the efficacy and tolerability of vildagliptin, a potent and selective dipeptidyl peptidase-4 inhibitor, as add-on to glimepiride in Japanese patients with Type 2 diabetes mellitus (T2DM) who were inadequately controlled.

METHODS

This 12-week, randomized, double-blind, placebo-controlled study compared vildagliptin 50mg twice-daily (n=102) with placebo (n=100) when added to a stable dose of glimepiride (>or=1mg/d).

RESULTS

Treatment groups were balanced at baseline (glycosylated hemoglobin [HbA(1c)], 7.9%; fasting plasma glucose, 163.8 mg/dL). During treatment HbA(1c) decreased progressively with vildagliptin, but remained unchanged with placebo. The adjusted mean change (AMDelta) at endpoint was -1.0+/-0.1 and -0.1+/-0.1% in vildagliptin- and placebo-treated patients (between-group Delta=-1.0+/-0.1%, P<0.001). A greater proportion of vildagliptin-treated patients had HbA(1c) <or=6.5% compared to placebo-treated patients (45% vs. 3%, P<0.001). The AMDelta FPG was -20.9+/-2.8 mg/dL with vildagliptin compared to 6.3+/-2.8 mg/dL with placebo (between-group Delta=-27.2+/-3.9 mg/dL, P<0.001). Patients in vildagliptin and placebo groups reported similar incidences of adverse events (AEs) (59.8% vs. 57.0%), serious AEs (0% vs. 2.0%), suspected drug-related AEs (21.6% vs. 23.0%), and discontinuation due to AEs (1.0% vs. 3.0%). Hypogylcaemia was reported in two (vildagliptin) and one (placebo) patient.

CONCLUSION

Vildagliptin is effective and well tolerated as an add-on to glimepiride in Japanese patients with T2DM.

Weight neutrality with the DPP-4 inhibitor, vildagliptin: mechanistic basis and clinical experience

Various factors may confound how diabetes medications affect a patient’s weight. Agents that induce hypoglycemia may promote weight gain through “defensive eating”. Conversely, patients whose hyperglycemia exceeds the renal glucose threshold may overeat to compensate for calories lost in urine and so gain weight when drug therapy ablates glycosuria. Some drugs, such as thiazolidinediones, may promote weight gain via increased lipid storage. Glucagon-like peptide-1 receptor agonists increase satiety, delay gastric emptying, and generally produce weight loss. Dipeptidyl peptidase (DPP)-4 inhibitors are generally weight-neutral, although modest weight loss has been observed with the DPP-4 inhibitor, vildagliptin, in patients with relatively low baseline glycemia. The weight neutrality of vildagliptin likely results in part from its intrinsically low risk for hypoglycemia. Recent studies point to additional potential mechanisms. One study found that drug-naïve patients randomized to vildagliptin exhibited significantly lower chylomicron lipid and apolipoprotein levels than placebo patients, suggesting that vildagliptin may inhibit intestinal fat extraction. Another trial found that patients randomized to vildagliptin versus placebo experienced paradoxical postprandial increases in markers of fatty acid mobilization and oxidation, in conjunction with increased sympathetic stimulation. Elaboration of these and other pathways could further clarify the origins of the favorable weight profile of vildagriptin.

Dipeptidyl peptidase-4 inhibitors for the treatment of type 2 diabetes mellitus

Type 2 diabetes mellitus traditionally has been characterized by insulin resistance and beta-cell dysfunction, leading to hyperglycemia and eventual micro- and macrovascular complications. Dipeptidyl peptidase-4 (DPP-4) inhibitors are a relatively new class of drugs available for the management of type 2 diabetes. In order to provide a comprehensive evaluation and comparison of the pharmacology, pharmacokinetics, efficacy, and safety of the DPP-4 inhibitors-sitagliptin, vildagliptin, saxagliptin, and alogliptin-in the treatment of type 2 diabetes, we conducted a MEDLINE search (1966-July 2009) for pertinent English-language articles. Abstracts of the annual meetings of the American Diabetes Association and European Association for the Study of Diabetes from 2005-2009 were also searched. As a drug class, the DPP-4 inhibitors have become widely accepted in clinical practice because of their low risk of hypoglycemia, favorable adverse-effect profile, and once-daily dosing. They are weight neutral (do not cause weight gain or loss) and appear to decrease beta-cell apoptosis and increase beta-cell survival. Because clinical studies directly comparing agents from this class have not, to our knowledge, been conducted, making comparisons in terms of efficacy and safety will become difficult for clinicians as more agents become available. Based on information from preclinical, clinical, and postmarketing data, there does not appear to be a compelling advantage of one DPP-4 inhibitor over another in terms of efficacy, safety, or ease of clinical use. Although theoretical advantages exist for agents with a higher specificity for DPP-4 inhibition versus inhibition of other isoenzymes associated with toxicity, comparative studies and/or increased clinical experience with this class of drug will determine the clinical advantages, if any, of one agent over another.

An assessment of adverse effects of vildagliptin versus comparators on the liver, the pancreas, the immune system, the skin and in patients with impaired renal function from a large pooled database of Phase II and III clinical trials

AIM

To assess the safety of vildagliptin versus all comparators (ACs) with regard to organs, systems or tissues of particular interest in type 2 diabetes (T2DM) and areas of potential concern with dipeptidyl peptidase-IV (DPP-4) inhibitors.

METHODS

Data were pooled from 38 studies where vildagliptin was given for > or =12 to > 104 weeks in patients with T2DM. Absolute and exposure-adjusted incidence rates and Peto odds ratios (ORs) versus ACs with corresponding 95% confidence intervals (CI) were calculated.

RESULTS

There were > 7000 subject-years of exposure (SYE) to vildagliptin 50 mg bid and > 6500 SYE to ACs. For mild hepatic enzyme elevations with and without elevated bilirubin levels, the ORs for vildagliptin 50 mg bid were 1.24 (95% CI: [0.80, 1.93]) and 1.19 (95% CI: [0.29, 4.90]), respectively. The exposure-adjusted incidences of markedly elevated hepatic enzymes and for enzyme elevations with bilirubin > or = 2x ULN with vildagliptin 50 mg bid were < or = those in the ACs group. For hepatic and pancreatitis-related AEs, the ORs for vildagliptin 50 mg bid were 0.87 (95% CI: [0.64, 1.19]) and 0.70 (95% CI: [0.26, 1.88]), respectively, and for any AE in the infections and infestations SOC, this was 1.04 (95% CI: [0.96, 1.13]). The incidences of skin-related AEs were low and the risk with vildagliptin 50 mg bid was not significantly different from ACs [(OR = 1.10 (95% CI: [0.80, 1.51])].

CONCLUSIONS

The present meta-analyses indicate that vildagliptin was not associated with increased risk of hepatic events or hepatic enzyme elevations indicative of drug-induced liver injury, pancreatitis, infections or skin-related toxicity.

Assessing the cardio-cerebrovascular safety of vildagliptin: meta-analysis of adjudicated events from a large Phase III type 2 diabetes population

AIM

To assess the cardiovascular and cerebrovascular (CCV) safety of the dipeptidyl peptidase-IV inhibitor vildagliptin.

METHODS

Data were pooled from 25 Phase III studies of vildagliptin, used either as monotherapy or combination therapy, with durations of 12 weeks to > or = 2 years. The safety of vildagliptin [50 mg qd (N = 1393) or 50 mg bid (N = 6116)] was assessed relative to a pool of all comparators [both placebo and active comparators (N = 6061)]. CCV events were adjudicated in a prospective, blinded fashion by an independent CCV adjudication committee. Meta-analysis of confirmed CCV events was performed with Mantel-Haenszel risk ratios (RRs); categories included in the composite endpoint were acute coronary syndrome, transient ischaemic attack (with imaging evidence of infarction), stroke and CCV death. Subgroup analyses by age (< and > or = 65 years), gender and cardiovascular (CV) risk status [high CV risk status defined as a previous history of events in the Standard MedDRA Queries of ischaemic heart disease, cardiac failure, ischaemic cerebrovascular conditions and/or embolic/thrombotic events, arterial) were also carried out. In addition, unadjusted and exposure-adjusted incidences are presented for both the composite endpoint and its components.

RESULTS

Relative to all comparators, the RRs for the composite endpoint were < 1 for both vildagliptin 50 mg qd [RR = 0.88; 95% CI (0.37, 2.11)] and vildagliptin 50 mg bid [RR = 0.84; 95% CI (0.62, 1.14)]. The results were consistent across subgroups defined by age, gender and CV risk status, including the higher CV risk subgroups of elderly patients [RR for vildagliptin 50 mg bid vs. all comparators = 1.04; 95% CI (0.62, 1.73)], males [RR = 0.87; 95% CI (0.60, 1.24)] or patients with a high CV risk status [RR = 0.78; 95% CI (0.51, 1.19)]. The exposure-adjusted incidences of each component of the composite endpoint for vildagliptin 50 mg bid were also lower than or similar to those of all comparators.

CONCLUSIONS

In a large meta-analysis, vildagliptin was not associated with an increased risk of adjudicated CCV events relative to all comparators in the broad population of type 2 diabetes including patients at increased risk of CCV events.

Comparing the actions of older and newer therapies on body weight: to what extent should these effects guide the selection of antidiabetic therapy?

BACKGROUND

Type 2 diabetes patients are usually overweight or obese. Further weight gain induced by antidiabetic treatment should be avoided if possible. Much attention has been focussed recently on the potential for GLP-1 mimetics, in particular, to reduce weight.

AIMS

Effects on weight are but one of several important criteria in selecting antidiabetic therapy, however. This review explores the effects on weight of older classes of antidiabetic agents (metformin, sulfonylureas, thiazolidinediones) and the newer drugs acting via the GLP-1 system. Other aspects of their therapeutic profiles and current therapeutic use are reviewed briefly to place effects on weight within a broader context.

FINDINGS

Comparative trials demonstrated weight neutrality or weight reduction with metformin, and weight increases with a sulfonylurea or thiazolidinedione. There was no clinically significant change in weight with DPP-4 inhibitors and a small and variable decrease in weight (about 3 kg or less) with GLP-1 mimetics. Improved clinical outcomes have been demonstrated for metformin and a sulfonylurea (cardiovascular and microvascular benefits, respectively, in the UK Prospective Diabetes Study), and secondary endpoints improved modestly with pioglitazone in the PROactive trial. No outcome benefits have been demonstrated to date with GLP-1-based therapies, and these agents exert little effect on cardiovascular risk factors. Concerns remain over long-term safety of these agents and this must be weighed against any potential benefit on weight management.

CONCLUSIONS

Considering effects on weight within the overall risk-benefit profile of antidiabetic therapies, metformin continues to justify its place at the head of current management algorithms for type 2 diabetes, due to its decades-long clinical evidence base, cardiovascular outcome benefits and low cost.

Dipeptydil peptidase-4 inhibitors in type 2 diabetes: a meta-analysis of randomized clinical trials

BACKGROUND AND AIM

The role of Dipeptidyl Peptidase-4 (DPP-4) inhibitors in the treatment of type 2 diabetes is debated; many recent trials, which were not included in previous meta-analyses, could add relevant information.

METHODS AND RESULTS

All available randomized controlled trials (RCTs), either published or unpublished, performed in type 2 diabetic patients with DPP-4 inhibitors, with a duration >12 weeks were meta-analyzed for HbA1c, BMI, hypoglycemia, and other adverse events. A total of 41 RCTs (9 of which are unpublished) was retrieved and included in the analysis. Gliptins determine a significant improvement of HbA1c in comparison with a placebo (-0.7 [-0.8:-0.6]), with a low risk of hypoglycemia. DPP-4 inhibitors show a similar efficacy in monotherapy and in combination with other agents. The risk of cardiovascular events and all-cause death with DPP-4 inhibitors is 0.76 [0.46-1.28] and 0.78 [0.40-1.51], respectively.

CONCLUSIONS

DPP-4 inhibitors reduce HbA1c, although to a lesser extent than sulphonylureas, with no weight gain and no hypoglycemic risk; further data are needed to assess their long-term safety.

A comparison of efficacy and safety of vildagliptin and gliclazide in combination with metformin in patients with Type 2 diabetes inadequately controlled with metformin alone: a 52-week, randomized study

AIM

To demonstrate non-inferiority of vildagliptin compared with gliclazide, as an add-on therapy, in patients with Type 2 diabetes inadequately controlled with metformin in a 52-week, randomized, double-blind, active-controlled study.

METHODS

Patients receiving a stable dose of metformin (> or = 1500 mg) were randomized (1 : 1) to receive vildagliptin (50 mg twice daily; n = 513) or gliclazide (up to 320 mg/day; n = 494).

RESULTS

Non-inferiority of vildagliptin was demonstrated (95% confidence interval -0.11%, 0.20%) with a mean change (se) from baseline glycated haemoglobin (HbA(1c)) (approximately 8.5% in both groups) to a 52-week endpoint of -0.81% (0.06) with vildagliptin and -0.85% (0.06) with gliclazide. Although a similar proportion of patients reached HbA(1c) < 7.0%, the total number of hypoglycaemic events was lower in the vildagliptin group (6 vs. 11 events). Vildagliptin was non-inferior (margin 0.6 mmol/l) to gliclazide in reducing fasting plasma glucose (1.31 vs. 1.52 mmol/l, P = 0.257). The overall incidence of any adverse events was similar in both groups (approximately 61%), but the number of serious adverse events was higher in the gliclazide group (8.7 vs. 6.7%). The number of patients who discontinued as a result of an unsatisfactory effect was higher in the vildagliptin group (n = 22 vs. 13, respectively) compared with gliclazide, but vildagliptin did not induce weight gain.

CONCLUSION

In patients with Type 2 diabetes inadequately controlled with metformin, addition of vildagliptin provided similar HbA(1c)-lowering efficacy compared with gliclazide after 52 weeks of treatment. Although both treatments were well tolerated, vildagliptin-treated patients had fewer hypoglycaemic events and did not gain weight.

Current developments in the treatment of diabetes: the incretin therapies

The prevalence of type 2 diabetes in the UK has increased enormously over recent years and is closely associated with obesity and other risk factors for cardiovascular disease. The incretin system, which contributes significantly to the insulin response in healthy individuals, but is impaired in individuals with diabetes, offers a target for the development of agents that address many aspects of diabetes. These agents are broadly split into two categories — the glucagon-like polypeptide-1 (GLP-1) receptor agonists and the dipeptidyl peptidase-4 (DPP-4) inhibitors. The DPP-4 inhibitors sitagliptin and vildagliptin, along with the GLP-1 receptor agonists exenatide and liraglutide are currently approved for use and offer effective glycaemic control with a low risk of hypoglycaemia. GLP-1 receptor agonists may offer further benefits over both DPP-4 inhibitors and conventional therapies, such as reductions in body weight and blood pressure. Here we review the incretin system (with particular reference to GLP-1) and consider the development of these two classes of antidiabetic therapy, discussing the safety and efficacy of some of the latest available GLP-1 receptor agonists and DPP-4 inhibitors.