Insights Into GLP-1 and GIP Actions Emerging From Vildagliptin Mechanism Studies in Man.

Vildagliptin blocks glucagon like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) inactivation of the meal induced increases in GLP-1 and GIP so that elevated GLP-1 and GIP levels are maintained over 24 h. The primary insulin secretion effect of vildagliptin is to improve the impaired sensitivity of the ß-cells to glucose in subjects with impaired fasting glucose (IFG) and impaired glucose tolerance (IGT) and in patients with type 2 diabetes mellitus (T2DM); this effect was seen acutely and maintained over at least 2 years in patients with T2DM. Vildagliptin was also associated with improved ß-cell function that is likely secondary to the improved metabolic state. Although there was no evidence of restoration of ß-cell mass, the preponderance of the vildagliptin data does indicate that for at least 2 years ß-cell function was maintained in vildagliptin treated patients but not in the untreated patients. Vildagliptin suppressed an inappropriate glucagon response to an oral glucose challenge in patients with T2DM, to a mixed meal challenge in patients with T2DM and type 1 diabetes mellitus, and to a mixed meal challenge in subjects with IGT and IFG. The improved glucagon response was maintained for at least 2 years in patients with T2DM and there was no change in the glucagon response in normoglycemic individuals. Vildagliptin lowered glucose levels into the normal range without increasing hypoglycemia. These hypoglycemic benefits appear to be secondary in large part to the improved sensitivity of both the ß and α-cell to glucose. In the case of the α-cell, if glucose levels are high, GLP-1 attenuates the glucagon levels and if glucose levels are low, GIP increases glucagon levels. Vildagliptin reduces fatty acid flux from the adipocyte leading to reduced liver fat which in turn leads to increased glucose utilization. The reduced glycosuria and reduced lipo-toxicity associated with vildagliptin therapy does not lead to weight gain presumably due to increased fat mobilization and oxidation during meals and to reduced fat extraction from the gut.

Factors that may Account for Cardiovascular Risk Reduction with a Dipeptidyl Peptidase-4 Inhibitor, Vildagliptin, in Young Patients with Type 2 Diabetes Mellitus.

INTRODUCTION: In a meta-analysis, we observed a significant 37% relative risk reduction in prospectively adjudicated major adverse cardiac events [MACEs, comprising of non-fatal myocardial infarction, non-fatal stroke, cardiovascular (CV) death] with vildagliptin vs. comparators in younger (< 65 years) patients with type 2 diabetes mellitus (T2DM), while the risk was similar in older patients (≥ 65 years). We carried out an exploratory analysis to identify the patient characteristics and on-treatment effects that may have contributed to the different outcomes in the two age groups. METHODS: On-treatment differences (vildagliptin vs. comparators) for the change from baseline in CV risk factors were analyzed using an analysis of covariance model with the baseline value for each variable of interest, treatment and study as covariates. Additional adjustments for background antihypertensive and statin use were performed when analyzing changes in blood pressure and lipids, respectively. Baseline characteristics and patient demographics were analyzed using descriptive statistics. RESULTS: Patients aged < 65 years had shorter diabetes duration (4.4 vs. 8.2 years) and slightly higher glycated hemoglobin (HbA1c) at baseline (8.3% vs. 8.0%) than patients aged ≥ 65 years. More patients in the  ≥ 65 year age group had hypertension (73.1% vs. 51.3%), dyslipidemia (53.3% vs. 43.9%) and a history of CV events (32.2% vs. 12.9%). There were small, but statistically significant differences in the change in HbA1c and total cholesterol in favor of vildagliptin relative to comparators, which were similar in both age groups. Significant differences were observed in the reduction in systolic blood pressure (SBP) (- 0.52 mmHg; 95% CI - 0.97, - 0.07; p = 0.023), low-density lipoprotein (LDL cholesterol) (- 0.12 mmol/l; 95% CI - 0.19, - 0.04; p = 0.002) and weight (- 0.48 kg; 95% CI - 0.95, - 0.01; p < 0.047) in patients < 65 years, but not in patients ≥ 65 years. The incidence of hypoglycemic events was lower in patients treated with vildagliptin [2.1 and 3.5 per 100 subject years exposure (SYEs) in < 65 and ≥ 65 years, respectively] than with comparators (5.8 and 7.5 per 100 SYEs, respectively). CONCLUSION: Based on our findings, it can be hypothesized that the positive effects of vildagliptin on SBP, LDL cholesterol, hypoglycemia and weight observed in younger, but not in older patients could be associated with the lower risk of MACE in younger patients with T2DM. FUNDING: Novartis.

DPP-4 inhibitor treatment: ß-cell response but not HbA1c reduction is dependent on the duration of diabetes.

INTRODUCTION: Dipeptidyl peptidase-4 (DPP-4) inhibitors reduce hyperglycemia in patients with type 2 diabetes mellitus (T2DM) by enhancing insulin and suppressing glucagon secretion. Since T2DM is associated with progressive loss of ß-cell function, we hypothesized that the DPP-4 inhibitor action to improve ß-cell function would be attenuated with longer duration of T2DM. METHODS: Data from six randomized, placebo-controlled trials of 24 weeks duration, where ß-cell response to vildagliptin 50 mg twice daily was assessed, were pooled. In each study, the insulin secretory rate relative to glucose (ISR/G 0-2h) during glucose load (standard meal or oral glucose tolerance test) was assessed at baseline and end of study. The mean placebo-subtracted difference (PSD) in the change in ISR/G 0-2h from baseline for each study was evaluated as a function of age, duration of T2DM, baseline ISR/G 0-2h, glycated hemoglobin (HbA1c), fasting plasma glucose, body mass index, and mean PSD in the change in HbA1c from baseline, using univariate model. RESULTS: There was a strong negative association between the PSD in the change from baseline in ISR/G 0-2h and duration of T2DM (r= -0.89, p<0.02). However, there was no association between the PSD in the change from baseline in ISR/G 0-2h and the PSD in the change from baseline in HbA1c (r=0.33, p=0.52). None of the other characteristics were significantly associated with mean PSD change in ISR/G 0-2h. CONCLUSION: These findings indicate that the response of the ß-cell, but not the HbA1c reduction, with vildagliptin is dependent on duration of T2DM. Further, it can be speculated that glucagon suppression may become the predominant mechanism via which glycemic control is improved when treatment with a DPP-4 inhibitor, such as vildagliptin, is initiated late in the natural course of T2DM.

The Vildagliptin Experience - 25 Years Since the Initiation of the Novartis Glucagon-like Peptide-1 Based Therapy Programme and 10 Years Since the First Vildagliptin Registration.

The discovery of the incretin hormone glucagon like peptide-1 (GLP-1), and its usefulness in the treatment of type 2 diabetes mellitus (T2DM) followed by the finding that dipeptidyl peptidase-4 (DPP-4) inhibition prevents GLP-1 inactivation, led to the discovery of DPP-728. In 1999, studies with DPP-728 established the first proof-of-concept that DPP-4 inhibition improves glycaemic control in patients with T2DM. Further efforts to improve the binding kinetics of DPP-728 resulted in the discovery of vildagliptin (LAF237). In the last 20 years, a plethora of studies conducted by Novartis in collaboration with external investigators has demonstrated the mechanism of action of vildagliptin and its efficacy as monotherapy and as an add-on therapy for patients with T2DM. The studies establish that vildagliptin is a selective DPP-4 inhibitor that blocks GLP-1 and glucose-dependent insulinotropic polypeptide (GIP) inactivation, thereby prolonging their action, resulting in improved glycaemic control. This review aims to discuss the discovery and development of vildagliptin, with an emphasis on mechanism of action and clinical efficacy.

Clinical Safety and Tolerability of Vildagliptin - Insights from Randomised Trials, Observational Studies and Post-marketing Surveillance.

Vildagliptin is one of the most extensively studied dipeptidyl peptidase-4 (DPP-4) inhibitors in terms of its clinical utility. Over the last decade, a vast panorama of evidence on the benefit-risk profile of vildagliptin has been generated in patients with type 2 diabetes mellitus (T2DM). In this article, we review the cumulative evidence on the safety of vildagliptin from the clinical development programme, as well as reports of rare adverse drug reactions detected during the post-marketing surveillance of the drug. Across clinical studies, the overall safety and tolerability profile of vildagliptin was similar to placebo, and it was supported by real-world data in a broad population of patients with T2DM, making DPP-4 inhibitors, like vildagliptin, a safe option for managing patients with T2DM.

In Vitro lipolysis is associated with whole-body lipid oxidation and weight gain in humans.

OBJECTIVE: To assess the association of adipocyte size with cellular lipolysis and between cellular lipolysis and whole-body lipid oxidation. This study also assessed the association between adipocyte size and cellular lipolysis with weight and fat mass gain. METHODS: Subjects had assessment of percent body fat (%fat) and adipose tissue biopsy for in vitro lipolysis (n = 325), and a subset of subjects had measurement of whole-body lipid oxidation (n = 112). A subset of subjects (n = 243) returned for repeated measurements of body weight and composition (mean follow-up 8.2 ± 5.5 years). RESULTS: In vitro lipolysis (r = 0.47, P < 0.0001) and adipocyte size (r = 0.49, P < 0.0001) were strongly associated with %fat. In vitro lipolysis (P = 0.04) but not adipocyte size (P = 0.44) was associated with whole-body fat oxidation. Adipocyte size was not associated with rate of percent weight gain (P = 0.20) but was negatively associated with rate of percent fat mass gain (P = 0.01). In vitro lipolysis was negatively associated with rate of percent weight gain (P = 0.02) and had a marginal negative association with rate of percent fat mass gain (P = 0.08). CONCLUSIONS: These results indicate inherent characteristics of adipocytes, including size and lipolytic activity, may be important determinants of whole-body lipid oxidation and subsequent weight gain.

Estimation of the Relative Contribution of Postprandial Glucose Exposure to Average Total Glucose Exposure in Subjects with Type 2 Diabetes.

We hypothesized that the relative contribution of fasting plasma glucose (FPG) versus postprandial plasma glucose (PPG) to glycated haemoglobin (HbA1c) could be calculated using an algorithm developed by the A1c-Derived Average Glucose (ADAG) study group to make HbA1c values more clinically relevant to patients. The algorithm estimates average glucose (eAG) exposure, which can be used to calculate apparent PPG (aPPG) by subtracting FPG. The hypothesis was tested in a large dataset (comprising 17 studies) from the vildagliptin clinical trial programme. We found that 24 weeks of treatment with vildagliptin monotherapy (n = 2523) reduced the relative contribution of aPPG to eAG from 8.12% to 2.95% (by 64%, p < 0.001). In contrast, when vildagliptin was added to metformin (n = 2752), the relative contribution of aPPG to eAG insignificantly increased from 1.59% to 2.56%. In conclusion, glucose peaks, which are often prominent in patients with type 2 diabetes, provide a small contribution to the total glucose exposure assessed by HbA1c, and the ADAG algorithm is not robust enough to assess this small relative contribution in patients receiving combination therapy.

Blood pressure and fasting lipid changes after 24 weeks' treatment with vildagliptin: a pooled analysis in >2,000 previously drug-naïve patients with type 2 diabetes mellitus.

INTRODUCTION: We have previously shown modest weight loss with vildagliptin treatment. Since body weight balance is associated with changes in blood pressure (BP) and fasting lipids, we have assessed these parameters following vildagliptin treatment. METHODS: Data were pooled from all double-blind, randomized, controlled, vildagliptin mono-therapy trials on previously drug-naïve patients with type 2 diabetes mellitus who received vildagliptin 50 mg once daily (qd) or twice daily (bid; n=2,108) and wherein BP and fasting lipid data were obtained. RESULTS: Data from patients receiving vildagliptin 50 mg qd or bid showed reductions from baseline to week 24 in systolic BP (from 132.5±0.32 to 129.8±0.34 mmHg; P<0.0001), diastolic BP (from 81.2±0.18 to 79.6±0.19 mmHg; P<0.0001), fasting triglycerides (from 2.00±0.02 to 1.80±0.02 mmol/L; P<0.0001), very low density lipoprotein cholesterol (from 0.90±0.01 to 0.83±0.01 mmol/L; P<0.0001), and low density lipoprotein cholesterol (from 3.17±0.02 to 3.04±0.02 mmol/L; P<0.0001), whereas high density lipoprotein cholesterol increased (from 1.19±0.01 to 1.22±0.01 mmol/L; P<0.001). Weight decreased by 0.48±0.08 kg (P<0.001). CONCLUSION: This large pooled analysis demonstrated that vildagliptin shows a significant reduction in BP and a favorable fasting lipid profile that are associated with modest weight loss.

Does the treatment of type 2 diabetes mellitus with the DPP-4 inhibitor vildagliptin reduce HbA1c to a greater extent in Japanese patients than in Caucasian patients?

BACKGROUND: Previous work suggests that Japanese patients with type 2 diabetes mellitus (T2DM) may respond more favorably to a DPP-4 (dipeptidyl peptidase-4) inhibitor than Caucasians. We aimed to compare the efficacy of the DPP-4 inhibitor vildagliptin (50 mg twice daily [bid]) between Japanese and Caucasian populations. METHODS: This analysis pooled data from 19 studies of drug-naïve patients with T2DM who were treated for 12 weeks with vildagliptin 50 mg bid as monotherapy. The pool comprised Japanese patients (n=338) who had been treated in Japan and Caucasian patients (n=1,275) who were treated elsewhere. Change from baseline (Δ) in glycated hemoglobin (HbA1c) at 12 weeks (in millimoles per mole) versus baseline HbA1c (both in percentage National Glycohemoglobin Standardization Program units [NGSP%] and millimoles per mole) for each population was reported. Universal HbA1c in millimoles per mole was calculated from either the Japanese Diabetes Society or the NGSP% HbA1c standards. RESULTS: At baseline, mean values for Japanese and Caucasian patients, respectively, were as follows: age, 59 years and 56 years; % male, 69% and 57%. The average HbA1c was reduced from 7.90% to 6.96% (Japanese Diabetes Society) and from 8.57% to 7.50% (United States National Glycohemoglobin Standardization Program), while HbA1c was reduced from 63 mmol/mol to 53 mmol/mol and from 70 mmol/mol to 58 mmol/mol in Japanese and Caucasians, respectively. ΔHbA1c increased with increasing baseline in both populations. The slopes were the same (0.41, r (2)=0.36; and 0.41, r (2)=0.15), and the intercepts were 15.4 mmol/mol and 17.2 mmol/mol, respectively. In Japanese patients, mean ΔHbA1c was greater by 1.7 mmol/mol (0.2% NGSP HbA1c) at any given baseline HbA1c than in Caucasians (P=0.01). CONCLUSION: The present pooled analysis suggests that Japanese patients respond better to vildagliptin treatment compared with Caucasians. However, when glycemic control was corrected by using the same glycemic standard, the difference in HbA1c reduction between these populations was not clinically meaningful.

Improved glucose regulation in type 2 diabetic patients with DPP-4 inhibitors: focus on alpha and beta cell function and lipid metabolism.

Inhibition of dipeptidyl peptidase-4 (DPP-4) is an established glucose-lowering strategy for the management of type 2 diabetes mellitus. DPP-4 inhibitors reduce both fasting and postprandial plasma glucose levels, resulting in reduced HbA1c with low risk for hypoglycaemia and weight gain. They act primarily by preventing inactivation of the incretin hormones glucose-dependent insulinotropic polypeptide and glucagon-like peptide-1, thereby prolonging the enhanced endogenous levels of these hormones after meal ingestion. This in turn causes islet and extrapancreatic effects, including increased glucose sensing in islet alpha and beta cells. These effects result in increased insulin secretion and decreased glucagon secretion being more effective in hyperglycaemic states and reduced insulin secretion and increased glucagon secretion being more effective during hypoglycaemia. Other secondary pharmacological actions of DPP-4 inhibitors include mobilisation and burning of fat during meals, decrease in fat extraction from the gut, reduction of fasting lipolysis and liver fat and increase in LDL particle size. These actions contribute to the clinical effects of DPP-4 inhibition, and the reduced demand for insulin could also lead to a durability benefit. This review summarises the current knowledge of the secondary pharmacological actions of DPP-4 inhibitors that lead to improved glucose regulation in patients with type 2 diabetes, focusing on alpha and beta cell function and lipid metabolism.

Four-Point Preprandial Self-Monitoring of Blood Glucose for the Assessment of Glycemic Control and Variability in Patients with Type 2 Diabetes Treated with Insulin and Vildagliptin.

The study explored the utility of four-point preprandial glucose self-monitoring to calculate several indices of glycemic control and variability in a study adding the DPP-4 inhibitor vildagliptin to ongoing insulin therapy. This analysis utilized data from a double-blind, randomized, placebo-controlled crossover study in 29 patients with type 2 diabetes treated with vildagliptin or placebo on top of stable insulin dose. During two 4-week treatment periods, self-monitoring of plasma glucose was undertaken at 4 occasions every day. Glucose values were used to assess several indices of glycemic control quality, such as glucose mean, GRADE, M-VALUE, hypoglycemia and hyperglycemia index, and indices of glycemic variability, such as standard deviation, CONGA, J-INDEX, and MAGE. We found that vildagliptin improved the glycemic condition compared to placebo: mean glycemic levels, and both GRADE and M-VALUE, were reduced by vildagliptin (P < 0.01). Indices also showed that vildagliptin reduced glycemia without increasing the risk for hypoglycemia. Almost all indices of glycemic variability showed an improvement of the glycemic condition with vildagliptin (P < 0.02), though more marked differences were shown by the more complex indices. In conclusion, the study shows that four-sample preprandial glucose self-monitoring is sufficient to yield information on the vildagliptin effects on glycemic control and variability.

Comparison of vildagliptin and sitagliptin in patients with type 2 diabetes and severe renal impairment: a randomised clinical trial.

AIMS/HYPOTHESIS: There are limited data comparing dipeptidyl peptidase-4 (DPP-4) inhibitors directly. We compared the safety and efficacy of vildagliptin and sitagliptin in patients with type 2 diabetes and severe renal impairment (RI). METHODS: This study was a parallel-arm, randomised, multicentre, double-blind, 24 week study conducted in 87 centres across Brazil and the USA. Patients with type 2 diabetes, either drug naive or treated with any glucose-lowering agents, who had inadequate glycaemic control (HbA1c 6.5-10.0% [48-86 mmol/mol]) and an estimated GFR <30 ml min(-1) [1.73 m](-2) were randomised (via interactive voice response technology) to vildagliptin 50 mg once daily or sitagliptin 25 mg once daily. These doses are recommended in this patient population and considered maximally effective. Participants, investigators and the sponsor were blinded to group assignment. Efficacy endpoints included change in HbA1c and fasting plasma glucose (FPG) at all visits and the primary safety endpoint was assessment of treatment-emergent adverse events. RESULTS: In total, 148 patients were randomised, 83 to vildagliptin and 65 to sitagliptin. All patients were analysed. After 24 weeks, the adjusted mean change in HbA1c was -0.54% (5.9 mmol/mol) from a baseline of 7.52% (59 mmol/mol) with vildagliptin and -0.56% (6.1 mmol/mol) from a baseline of 7.80% (62 mmol/mol) with sitagliptin (p = 0.874). FPG decreased by 0.47 ± 0.37 mmol/l with vildagliptin and increased by 0.16 ± 0.43 mmol/l with sitagliptin (p = 0.185). Both treatments were well tolerated with overall similar safety profiles. CONCLUSIONS/INTERPRETATION: At their recommended doses for severe RI, vildagliptin (50 mg once daily) compared with sitagliptin (25 mg once daily) demonstrated similar efficacy and both drugs were well tolerated. This study provides further support for the use of DPP-4 inhibitors in patients with severe RI. TRIAL REGISTRATION: ClinicalTrials.gov NCT00616811 (completed) FUNDING: This study was planned and conducted by Novartis.

Effect of vildagliptin on hepatic steatosis.

CONTEXT: Although dipeptidyl-peptidase-4 inhibitors exert their major action via an incretin mechanism, a favorable effect of vildagliptin on lipid metabolism remains unexplained. OBJECTIVE: The objective was to examine hepatic triglyceride levels and insulin sensitivity on vildagliptin. DESIGN: This was a 6-month, randomized, double-blind, placebo-controlled trial. SETTING: This was an outpatient study at a university clinical research center. PATIENTS: Individuals with type 2 diabetes (n = 44) and glycated hemoglobin ≤ 7.6% on stable metformin therapy were included. INTERVENTION: Intervention was vildagliptin 50 mg twice a day or placebo over 6 months. MAIN OUTCOME MEASURES: Main outcome measures were hepatic triglyceride levels and insulin sensitivity. RESULTS: Mean fasting liver triglyceride content decreased by 27% with vildagliptin, from 7.3 ± 1.0% (baseline) to 5.3 ± 0.9% (endpoint). There was no change in the placebo group. The between-group difference in change from baseline was significant (P = .013). Mean fasting plasma glucose concentration decreased over the study period with vildagliptin vs placebo by -1.0 mmol/L (P = .018), and there was a positive correlation between these decrements and liver triglyceride in the vildagliptin group at 3 months (r = 0.47; P = .02) and 6 months (r = 0.44; P = .03). Plasma alanine aminotransferase fell from 27.2 ± 2.8 to 20.3 ± 1.4 IU/L in the vildagliptin group (P = .0007), and there was a correlation between the decrements in alanine aminotransferase and liver triglyceride (r = 0.83; P < .0001). Insulin sensitivity during the euglycemic clamp was similar in each group at baseline (3.24 ± 0.30 vs 3.19 ± 0.38 mg/kg/min) and did not change (adjusted mean change of 0.26 ± 0.22 vs 0.32 ± 0.22 mg/kg/min; P = .86). Mean body weight decreased by 1.6 ± 0.5 vs 0.4 ± 0.5 kg in the vildagliptin and placebo groups, respectively (P = .08). CONCLUSIONS: This study demonstrates that the dipeptidyl-peptidase-4 inhibitor vildagliptin brings about a clinically significant decrease in hepatic triglyceride levels during 6 months of therapy unrelated to change in body weight. There was no change in peripheral insulin sensitivity.

Changes in body weight after 24 weeks of vildagliptin therapy as a function of fasting glucose levels in patients with type 2 diabetes.

BACKGROUND: In order to test the hypothesis that the degree of weight change with the dipeptidyl peptidase-4 inhibitor vildagliptin is dependent on the level of glycemic control at baseline, the weight changes from pooled monotherapy studies after 24 weeks of therapy with vildagliptin were assessed versus the fasting plasma glucose (FPG) levels at baseline. METHODS: Data were pooled from eight clinical monotherapy trials including 2,340 previously drug-naïve patients with type 2 diabetes mellitus who received vildagliptin monotherapy (50 mg once daily [n=359] or 50 mg twice daily [n=1,981]). The trials were all randomized, double-blind, controlled clinical trials with a prespecified week 24 study visit. RESULTS: Linear regression analysis of weight change after 24 weeks relative to baseline FPG showed an intercept of -2.259 kg (95% confidence interval -2.86, -1.66; P<0.0001) and a positive slope of 0.1552 kg (95% confidence interval 0.10-0.21; P<0.0001). Neutral caloric balance (no weight change) was observed at a FPG of 14.6 mmol/L (263 mg/dL). Baseline FPG values below and above this threshold were associated with weight loss and weight gain, respectively. For instance, from this analysis, a baseline FPG of 8 mmol/L (144 mg/dL) predicts a weight loss of 1 kg. CONCLUSION: The present analysis showed that treatment with vildagliptin results in a negative caloric balance when glucose levels are below the renal threshold at baseline.

Efficacy of vildagliptin versus sulfonylureas as add-on therapy to metformin: comparison of results from randomised controlled and observational studies.

AIMS/HYPOTHESIS: Randomised control trials (RCTs) do not always reflect real-life outcomes for glucose-lowering drugs. In this work we compared RCT and real-life data on the efficacy of the dipeptidyl peptidase-IV (DPP-4) inhibitor vildagliptin or sulfonylureas when added to metformin. METHODS: Data were pooled from five RCTs examining vildagliptin (n = 2,788) and sulfonylureas (glimepiride [n = 1,259] or gliclazide [n = 433]), added to metformin. For real-life conditions, data were extracted from an observational study examining vildagliptin (n = 7,002) or sulfonylureas (n = 3,702), added to metformin monotherapy. Linear regression analyses were performed between the baseline HbA1c and the change in HbA1c (Δ HbA1c) after 24 weeks. RESULTS: Baseline HbA1c correlated to Δ HbA1c (r (2) = 0.36, slope = -0.54 [95% CI -0.55, -0.53; p < 0.0001]) for both treatments. With sulfonylureas, the slope of the correlation was steeper in the observational study than in RCTs (interaction coefficient = -0.327, p < 0.001), whereas for vildagliptin, the slope was virtually identical in the observational study and the RCTs (interaction coefficient = 0.024, p = 0.175). For any given baseline HbA1c, Δ HbA1c with sulfonylureas was smaller in real life than in RCTs, whereas Δ HbA1c with vildagliptin was the same. CONCLUSIONS/INTERPRETATIONS: When comparing RCT to real-life data, the decrease in HbA1c from baseline with sulfonylurea treatment is smaller in real life than in RCTs, whereas the reduction with vildagliptin is essentially the same, suggesting that the full power of treatment is retained in real life for vildagliptin but not for sulfonylureas, possibly due to fear of hypoglycaemia.

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 m(2)) 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 m(2), 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.

Clinical evidence and mechanistic basis for vildagliptin's effect in combination with insulin.

Due to the progressive nature of type 2 diabetes, many patients need insulin as add-on to oral antidiabetic drugs (OADs) in order to maintain adequate glycemic control. Insulin therapy primarily targets elevated fasting glycemia but is less effective to reduce postprandial hyperglycemia. In addition, the risk of hypoglycemia limits its effectiveness and there is a concern of weight gain. These drawbacks may be overcome by combining insulin with incretin-based therapies as these increase glucose sensitivity of both the α- and ß-cells, resulting in improved postprandial glycemia without the hypoglycemia and weight gain associated with increasing the dose of insulin. The dipeptidyl peptidase-IV (DPP-4) inhibitor vildagliptin has also been shown to protect from hypoglycemia by enhancing glucagon counterregulation. The effectiveness of combining vildagliptin with insulin was demonstrated in three different studies in which vildagliptin decreased A1C levels when added to insulin therapy without increasing hypoglycemia. This was established with and without concomitant metformin therapy. Furthermore, the effectiveness of vildagliptin appears to be greater when insulin is used as a basal regimen as opposed to being used to reduce postprandial hyperglycemia, since improvement in insulin secretion likely plays a minor role when relatively high doses of insulin are administered before meals. This article reviews the clinical experience with the combination of vildagliptin and insulin and discusses the mechanistic basis for the beneficial effects of the combination. The data support the use of vildagliptin in combination with insulin in general and, in line with emerging clinical practice, suggest that treating patients with vildagliptin, metformin, and basal insulin could be an attractive therapeutic option.

Vildagliptin reduces glucagon during hyperglycemia and sustains glucagon counterregulation during hypoglycemia in type 1 diabetes.

CONTEXT: The dipeptidyl peptidase-4 inhibitor, vildagliptin, inhibits glucagon secretion at hyperglycemia but appears to enhance glucagon counterregulation during hypoglycemia in type 2 diabetes. OBJECTIVE: The objective of the investigation was to study whether vildagliptin also improves α-cell function in type 1 diabetes (T1D). PATIENTS AND METHODS: The study was a single-center, double-blind, randomized, placebo-controlled crossover study involving 28 patients with C-peptide negative and antibody positive T1D [21 males, seven females, glycosylated hemoglobin 57.9 mmol/mol (7.5%)]. Patients received vildagliptin (50 mg twice a day) or placebo as an add-on to their insulin therapy for 4 wk each. On d 28 of the respective treatment period, patients were served a standard meal (500 kcal) to raise the circulating incretin hormone levels followed by a hyperinsulinemic hypoglycemic clamp at 2.5 mmol/liter. MAIN OUTCOME MEASURE: The increase in plasma glucagon levels during the 30-min hypoglycemic clamp (min 165-195 of the test) was measured. RESULTS: During the meal, glucagon levels were lower with vildagliptin than with placebo (120 min area under the curve(glucagon) 2.4±0.2 vs. 2.6±0.2 nmol/liter×minutes, P=0.022 for between group difference). In contrast, during hypoglycemia, the glucagon counterregulation was not reduced by vildagliptin (increase in glucagon 1.5±1.0 pmol/liter with vildagliptin vs. 1.7±0.8 pmol/liter with placebo, P=NS). In addition, the counterregulatory responses in epinephrine, norepinephrine, cortisol, and pancreatic polypeptide were not different between the treatments. During the 4-wk treatment period, vildagliptin reduced the mean glycosylated hemoglobin, whereas there was no change with placebo [between group difference was -3.4±1.0 mmol/mol (-0.32±0.09%; P=0.002)] from baseline of 57.9 mmol/mol (7.5%). CONCLUSIONS: Vildagliptin, although inhibiting glucagon secretion during hyperglycemia, does not compromise the glucagon counterregulatory response during hypoglycemia in T1D.

Impact of insulin resistance, body mass index, disease duration, and duration of metformin use on the efficacy of vildagliptin.

INTRODUCTION: The optimal stage for dipeptidyl peptidase-4 (DPP-4) inhibitor therapy in the course of type 2 diabetes mellitus (T2DM) is still under discussion, with often a perception that treatment with these agents may be less beneficial with increasing disease progression, due to loss of beta-cell function, and with increasing insulin resistance (IR), where beta-cell function is less prominent. This work, therefore, aimed to assess the impact of such factors on the efficacy of the DPP-4 inhibitor, vildagliptin, in add-on therapy to metformin. METHODS: A pooled analysis of 24-week efficacy data of vildagliptin 50 mg twice daily (b.i.d.) (n = 2,478) from four add-on to metformin studies was performed. Analyses for changes in hemoglobin A(1c) (HbA(1c)) were stratified according to baseline IR stage (homeostasis model assessment [Homa IR] <5, ≥5), body mass index (BMI) (<27, ≥27 to <30, ≥30 kg/m(2)), T2DM duration (0 to <1, ≥1 to <5, ≥5 years), and duration of metformin use (0 to <1, ≥1 to <5, ≥5 years). Data from patients treated with sulfonylureas (SUs) (n = 2,010) in the pooled studies are provided as reference. RESULTS: Patients in the vildagliptin and SU groups had mean age, HbA(1c), BMI, Homa IR, duration of T2DM and metformin use of 58 years, 7.7%, 32 kg/m(2), 4.3, 5.9 years and 3.0 years, respectively. Reductions from baseline in HbA(1c) with vildagliptin were very similar across Homa IR (mean 2.8 and 8.6), BMI (mean 24.9, 28.5, and 35.3 kg/m(2)), T2DM duration (mean 0.6, 2.9, and 9.7 years), and duration of metformin use (mean 0.6, 2.6, and 7.9 years) categories, showing significant drops in HbA(1c) of approximately -0.7% (baseline 7.7%). The results in patients receiving SUs were comparable to those seen in the vildagliptin group. CONCLUSION: Vildagliptin add-on therapy to metformin was efficacious independent of IR stage and BMI, as well as disease duration and duration of prior metformin use, indicating that, contrary to a not uncommon perception, more obese patients and patients with long-standing T2DM can benefit from treatment with the DPP-4 inhibitor, vildagliptin.