Effect of vildagliptin as add-on therapy to a low-dose metformin

Management of Glucocorticoid-Induced Hyperglycemia

Glucocorticoids are potent immunosuppressive and anti-inflammatory drugs used for various systemic and localized conditions. The use of glucocorticoids needs to be weighed against their adverse effect of aggravating hyperglycemia in persons with diabetes mellitus, unmask undiagnosed diabetes mellitus, or precipitate glucocorticoid-induced diabetes mellitus appearance. Hyperglycemia is associated with poor clinical outcomes, including infection, disability after hospital discharge, prolonged hospital stay, and death. Furthermore, clear guidelines for managing glucocorticoid-induced hyperglycemia are lacking. Therefore, this consensus document aims to develop guidance on the management of glucocorticoid-induced hyperglycemia. Twenty expert endocrinologists, in a virtual meeting, discussed the evidence and practical experience of real-life management of glucocorticoid-induced hyperglycemia. The expert group concluded that we should be proactive in terms of diagnosis, management, and post-steroid care. Since every patient has different severity of underlying disease, clinical stratification would help understand patient profiles and determine the treatment course. Patients at home with pre-existing diabetes who are already on oral or injectable therapy can continue the same as long as they are clinically stable and eating adequately. However, depending on the degree of hyperglycemia, modification of doses may be required. Initiating basal bolus with correction regimen is recommended for patients in non-intensive care unit settings. For patients in intensive care unit, variable rate intravenous insulin infusion could be temporarily used, but under supervision of diabetes inpatient team, and patients can be transitioned to subcutaneous insulin once stable baseline assessment and continual evaluation are crucial for day-to-day decisions concerning insulin doses. Glycemic variability should be carefully monitored, and interventions to treat patients should also aim at achieving and maintaining euglycemia. Rational use of glucose-lowering drugs is recommended and treatment regimen should ensure maximum safety for both patient and provider. Glucovigilance is required as the steroids taper during transition, and insulin dosage should be reduced subsequently. Increased clinical and economic burden resulting from corticosteroid-related adverse events highlights the need for effective management. Therefore, these recommendations would help successfully manage GC-induced hyperglycemia and judiciously allocate resources.

Optimization of Metformin in the GRADE Cohort: Effect on Glycemia and Body Weight

OBJECTIVE

We evaluated the effect of optimizing metformin dosing on glycemia and body weight in type 2 diabetes.

RESEARCH DESIGN AND METHODS

This was a prespecified analysis of 6,823 participants in the Glycemia Reduction Approaches in Diabetes: A Comparative Effectiveness Study (GRADE) taking metformin as the sole glucose-lowering drug who completed a 4- to 14-week (mean ± SD 7.9 ± 2.4) run-in in which metformin was adjusted to 2,000 mg/day or a maximally tolerated lower dose. Participants had type 2 diabetes for <10 years and an HbA1c ≥6.8% (51 mmol/mol) while taking ≥500 mg of metformin/day. Participants also received diet and exercise counseling. The primary outcome was the change in HbA1c during run-in.

RESULTS

Adjusted for duration of run-in, the mean ± SD change in HbA1c was -0.65 ± 0.02% (-7.1 ± 0.2 mmol/mol) when the dose was increased by ≥1,000 mg/day, -0.48 ± 0.02% (-5.2 ± 0.2 mmol/mol) when the dose was unchanged, and -0.23 ± 0.07% (-2.5 ± 0.8 mmol/mol) when the dose was decreased (n = 2,169, 3,548, and 192, respectively). Higher HbA1c at entry predicted greater reduction in HbA1c (P < 0.001) in univariate and multivariate analyses. Weight loss adjusted for duration of run-in averaged 0.91 ± 0.05 kg in participants who increased metformin by ≥1,000 mg/day (n = 1,894).

CONCLUSIONS

Optimizing metformin to 2,000 mg/day or a maximally tolerated lower dose combined with emphasis on medication adherence and lifestyle can improve glycemia in type 2 diabetes and HbA1c values ≥6.8% (51 mmol/mol). These findings may help guide efforts to optimize metformin therapy among persons with type 2 diabetes and suboptimal glycemic control.

Reduction in HbA1c with SGLT2 inhibitors vs. DPP-4 inhibitors as add-ons to metformin monotherapy according to baseline HbA1c: A systematic review of randomized controlled trials

AIMS

This study compared the reduction of glycated haemoglobin (HbA1c) with sodium-glucose cotransporter type-2 inhibitors (SGLT2is) vs. dipeptidyl peptidase-4 inhibitors (DPP-4is) as add-ons to metformin in patients with type 2 diabetes mellitus (T2DM), with a specific focus on HbA1c changes according to baseline HbA1c.

MATERIALS AND METHODS

Electronic databases were scrutinized for randomized controlled trials (RCTs) evaluating the reduction of HbA1c from baseline (Δ HbA1c) with an SGLT2i or DPP-4i in patients with T2DM not well controlled by metformin monotherapy. The endpoint was Δ HbA1c using both indirect and direct comparisons.

RESULTS

Overall, Δ HbA1c was slightly greater with SGLT2is (-0.80±0.20% from 8.03±0.35%; 44 analyses, 29 RCTs, 15 with two doses, n=9321) than with DPP-4is (-0.71±0.23% from 8.05±0.43%; 61 analyses, 59 RCTs, n=17,914; P=0.0354). When the mean baseline HbA1c was<8% ([64mmol/mol] 7.79±0.15% vs. 7.71±0.23%), Δ HbA1c averaged -0.735±0.17% vs. -0.62±0.16% (P=0.0117) with SGLT2is vs. DPP-4is, respectively. However, this difference vanished when the mean baseline HbA1c was≥8% (-0.87±0.22% from 8.27±0.32% with SGLT2is vs. -0.80±0.24% from 8.35±0.33% with DPP-4is; P=0.2756). The relationship between Δ HbA1c and baseline HbA1c was only slightly stronger with SGLT2is (slope: -0.39, r²=-0.43; P<0.0001) than with DPP-4is (slope: -0.26, r²=-0.25; P<0.0001).

CONCLUSION

Because of the small difference in Δ HbA1c whatever the baseline HbA1c level with SGLT2is vs. DPP-4is as add-ons to metformin, choosing between these glucose-lowering agents in clinical practice should be based on other efficacy criteria (such as weight and blood pressure changes, cardiovascular and renal protection) or on safety profiles rather than on HbA1c levels.

Comparison of the Effectiveness and Safety of Vildagliptin Add-On to Metformin Versus Other Oral Dual Antidiabetes Agents in Patients with Type 2 Diabetes: The China Prospective Diabetes Study

INTRODUCTION

The efficacy and safety of vildagliptin alone or with metformin is well established by randomized trials, but it is unknown whether it can be extrapolated to the real-world setting in Chinese patients with type 2 diabetes mellitus (T2DM). This study aimed to assess the effectiveness and safety of vildagliptin add-on to metformin versus dual oral antidiabetes drug (OAD), non-vildagliptin combination therapies in real-world Chinese patients with T2DM.

METHODS

The China Prospective Diabetes Study was a post-marketing, prospective, multicenter, observational, real-world study conducted in 52 centers. Patients inadequately controlled with OAD monotherapy and who initiated vildagliptin add-on to metformin (VM cohort) or two OADs other than vildagliptin (comparator cohort) were included for the present analysis. The composite primary endpoint was glycated hemoglobin (HbA1c) <  7% and without tolerability events (hypoglycemia, weight gain ≥ 3%, or discontinuation due to gastrointestinal events) at 12 months. Secondary endpoints included change in HbA1c from baseline, subgroup analysis, and tolerability. Propensity score matching analysis was performed to adjust for baseline covariates imbalance (body mass index (BMI) and HbA1c).

RESULTS

A total of 604 patients received VM and 670 received comparator therapy. Patients who received VM were younger, more obese, and had a higher baseline HbA1c and a shorter duration of T2DM. After propensity score matching, there were 530 patients per cohort. After 12-month treatment, the success rates of the composite primary endpoint were 50.9% and 33.0% in the VM and comparator cohorts, respectively (P < 0.001; odds ratio = 2.10, 95% confidence interval (CI) 1.64-2.70). Furthermore, the success rates of the composite endpoint were higher with VM across geographic area, BMI, and baseline HbA1c subgroups. Fewer tolerability events occurred in the VM cohort versus the comparator cohort (8.3% vs. 16.2%, P < 0.001; relative risk = 0.51, 95% CI 0.36-0.72).

CONCLUSION

Compared with dual OAD non-vildagliptin combination therapies, vildagliptin add-on to metformin is effective and safe to achieve glycemic control in Chinese patients with T2DM.

FUNDING

Novartis.

Double-blind, randomized clinical trial assessing the efficacy and safety of early initiation of sitagliptin during metformin uptitration in the treatment of patients with type 2 diabetes: The CompoSIT-M study

AIMS

To characterize the glycaemic efficacy and safety of initiation of the dipeptidyl peptidase-4 inhibitor sitagliptin during metformin dose escalation in people with type 2 diabetes (T2D) not at glycated haemoglobin (HbA1c) goal on a sub-maximal dose of metformin.

MATERIALS AND METHODS

Study participants with HbA1c ≥58 mmol/mol and ≤97 mmol/mol (≥7.5% and ≤11.0%) while on 1000 mg/d metformin were randomized to sitagliptin 100 mg once daily or placebo. All were to uptitrate metformin to 2000 mg/d. A longitudinal data analysis model was used to test the primary hypothesis that sitagliptin is superior to placebo when initiated during uptitration of metformin in reducing HbA1c at week 20. [ClinicalTrials.gov Identifier: NCT02791490, EudraCT: 2015-004224-59] RESULTS: A total of 458 participants (mean HbA1c 71.1 mmol/mol [8.7%], T2D duration 6.3 years) were treated. After 20 weeks, the least squares (LS) mean changes from baseline in HbA1c were -12.1 mmol/mol (-14.0, -10.1) (-1.10% [-1.28, -0.93]) and -7.6 mmol/mol (-9.6, -5.6) (-0.69% [-0.88, -0.51]) with sitagliptin and placebo, respectively; the between-group difference in LS mean changes from baseline HbA1c was -4.5 mmol/mol (-6.5, -2.5) (-0.41% [-0.59, -0.23]); P < 0.001. The likelihood of having HbA1c <53 mmol/mol (<7.0%) at week 20 was higher in the sitagliptin group than in the placebo group in the overall population (relative risk 1.7, P = 0.002) and in those with a baseline HbA1c ≥69 mmol/mol (≥8.5%) (relative risk 2.4, P = 0.026). There were no notable differences between groups with regard to adverse events overall, hypoglycaemia events, changes in body weight or other safety variables.

CONCLUSION

In participants not at HbA1c goal on a sub-maximal dose of metformin, addition of sitagliptin at the time of metformin dose uptitration improved glycaemic response and HbA1c goal attainment, with similar safety and tolerability, compared to metformin uptitration alone.

Baseline Triglyceride Level Affected the Efficacy of Vildagliptin in Treating Type 2 Diabetes: A Post Hoc Analysis of the VISION Study

Identifying factors that may impact vildagliptin's efficacy could contribute to individualized treatment for patients with type 2 diabetes. In the current study, we aimed to assess the correlation between patient baseline triglyceride (TG) and efficacy of vildagliptin in Chinese patients with type 2 diabetes in a post hoc analysis of the VISION study. TG-based subgroup analysis was performed to evaluate baseline TG's impact on the decrease of glycated hemoglobin (HbA_1c) in patients receiving vildagliptin plus low-dose metformin (VLDM) vs. high-dose metformin (HDM). Additionally, multivariate linear regression was performed to assess the association between baseline TG and HbA_1c reduction at weeks 12 and 24 for patients receiving VLDM vs. HDM. For patients receiving VLDM, baseline TG ≤ 2.03 mmol/L was associated with significantly greater HbA_1c reduction vs. TG > 2.03 mmol/L at week 12, but not at week 24. Additionally, multivariate linear regression analysis revealed a significant independent association and an association short of statistical significance between patient baseline TG and the HbA_1c-reducing efficacy of VLDM at weeks 12 (P < 0.001) and 24 (P = 0.082), respectively, while such association was absent for HDM. Collectively, baseline TG was an independent predictive factor for the efficacy of a dipeptidyl peptidase-IV in treating type 2 diabetes during its initial use.

Efficacy and safety of combination therapy with vildagliptin and metformin versus metformin uptitration in Chinese patients with type 2 diabetes inadequately controlled with metformin monotherapy: a randomized, open-label, prospective study (VISION)

AIMS

To compare the efficacy and safety of combination of vildagliptin and metformin therapy with metformin uptitration in Chinese patients with type 2 diabetes (T2DM) inadequately controlled with low-dose metformin.

METHODS

In this 24-week prospective, randomized, multicentre, open-label study, patients with T2DM inadequately controlled with metformin ≤1000 mg daily were divided 1 : 1 : 1 : 1 into four prespecified subgroups based on age and body mass index (BMI). Patients in each subgroup were randomized 5 : 1 to receive either vildagliptin (50 mg twice daily) plus metformin [500 mg twice daily; vildagliptin and low-dose metformin (VLDM) group] or metformin uptitration [1000 mg twice daily; high-dose metformin (HDM) group]. The primary endpoint was change in glycated haemoglobin (HbA1c) from baseline at week 24. The key secondary endpoints included percentage of patients achieving target HbA1c without adverse gastrointestinal (GI) events and mean change in fasting plasma glucose (FPG) from baseline to week 24.

RESULTS

A total of 3084 patients were randomized. HbA1c reduction of 0.54% at week 24 in the VLDM group was non-inferior and statistically superior compared with 0.40% in the HDM group (P < 0.0001). VLDM's non-inferiority to HDM was confirmed in the four subgroups and its superiority was shown for all subgroups (p < 0.05) except for the subgroup of patients aged <60 years with a BMI of ≥24 kg/m(2) . Compared with HDM, VLDM significantly increased the percentage of patients achieving HbA1c ≤6.5% and HbA1c ≤6.5% without GI events. FPG levels in the VLDM group were lower at week 24 numerically than in the HDM group. The two treatment arms had similar safety profiles.

CONCLUSIONS

VLDM was non-inferior and statistically superior to HDM in glycaemic control in Chinese patients with T2DM inadequately controlled with low-dose metformin.

Systematic review and meta-analysis of vildagliptin for treatment of type 2 diabetes

This systematic review and meta-analysis provides an update on the efficacy and safety of vildagliptin for treatment of type 2 diabetes mellitus (T2DM). We searched MEDLINE, COCHRANE, EMBASE and the drug manufacturer's website for randomised controlled trials of vildagliptin in patients with T2DM. Sixty-nine studies (28,006 patients) were included in the meta-analysis. Compared with placebo vildagliptin reduced HbA1c (weighted mean difference WMD -0.69 %; 95 % CI -0.83 to -0.56 %; I (2) = 82 %), and it was as effective as other antidiabetic agents (WMD -0.01 %; 95 % CI -0.16 to 0.14 %; I (2) = 93 %), without increasing the risk for hypoglycemia (OR 0.83; 95 % CI 0.59 to 1.16; I (2) = 0 % vs. placebo, and OR 0.19; 95 % CI 0.15 to 0.24; I (2) = 78 % versus active comparators). However, it was associated with an increase in the incidence of arthralgia compared with other comparators (OR 1.23; 95 % CI 1.02 to 1.48; I (2) = 0 %). On the contrary, vildagliptin did not increase the incidence of pancreatitis (OR 0.97; 95 % CI 0.37 to 2.53; I (2) = 0 %), serious adverse events (OR 0.98; 95 % CI 0.88 to 1.09; I (2) = 0 %) or death (OR 1.10, 95 % CI 0.75 to 1.61; I (2) = 0 %). Finally, odds ratio (OR) for heart failure, and overall cardiovascular and cerebrovascular events was 0.77 (95 % CI 0.46 to 1.30; I (2) = 0 %) and 0.91 (95 % CI 0.73 to 1.14; I (2) = 0 %), respectively. Vildagliptin is an effective and safe therapeutic option for patients with T2DM, both as monotherapy and as add-on treatment.

Cardiovascular and heart failure safety profile of vildagliptin: a meta-analysis of 17 000 patients

AIMS

To report the cardiovascular (CV) safety profile and heart failure (HF) risk of vildagliptin from a large pool of studies, including trials in high-risk patients with type 2 diabetes mellitus (T2DM), such as those with congestive HF and/or moderate/severe renal impairment.

METHODS

We conducted a retrospective meta-analysis of prospectively adjudicated CV events. Patient-level data were pooled from 40 double-blind, randomized controlled phase III and IV vildagliptin studies. The primary endpoint was occurrence of major adverse CV events (MACEs; myocardial infarction, stroke and CV death). Assessments of the individual MACE components and HF events (requiring hospitalization or new onset) were secondary endpoints. The risk ratio (RR) of vildagliptin (50 mg once- and twice-daily combined) versus comparators (placebo and all non-vildagliptin treatments) was calculated using the Mantel-Haenszel (M-H) method.

RESULTS

Of the 17 446 patients, 9599 received vildagliptin (9251.4 subject-years of exposure) and 7847 received comparators (7317.0 subject-years of exposure). The mean age of the patients was 57 years, body mass index 30.5 kg/m(2) (nearly 50% obese), glycated haemoglobin concentration 8.1% and T2DM duration 5.5 years. A MACE occurred in 83 (0.86%) vildagliptin-treated patients and 85 (1.20%) comparator-treated patients, with an M-H RR of 0.82 [95% confidence interval (CI) 0.61-1.11]. Similar RRs were observed for the individual events. Confirmed HF events were reported in 41 (0.43%) vildagliptin-treated patients and 32 (0.45%) comparator-treated patients, with an M-H RR 1.08 (95% CI 0.68-1.70).

CONCLUSIONS

This large meta-analysis indicates that vildagliptin is not associated with an increased risk of adjudicated MACEs relative to comparators. Moreover, this analysis did not find a significant increased risk of HF in vildagliptin-treated patients.

Choice of estimand and analysis methods in diabetes trials with rescue medication

The analysis of clinical trials aiming to show symptomatic benefits is often complicated by the ethical requirement for rescue medication when the disease state of patients worsens. In type 2 diabetes trials, patients receive glucose-lowering rescue medications continuously for the remaining trial duration, if one of several markers of glycemic control exceeds pre-specified thresholds. This may mask differences in glycemic values between treatment groups, because it will occur more frequently in less effective treatment groups. Traditionally, the last pre-rescue medication value was carried forward and analyzed as the end-of-trial value. The deficits of such simplistic single imputation approaches are increasingly recognized by regulatory authorities and trialists. We discuss alternative approaches and evaluate them through a simulation study. When the estimand of interest is the effect attributable to the treatments initially assigned at randomization, then our recommendation for estimation and hypothesis testing is to treat data after meeting rescue criteria as deterministically 'missing' at random, because initiation of rescue medication is determined by observed in-trial values. An appropriate imputation of values after meeting rescue criteria is then possible either directly through multiple imputation or implicitly with a repeated measures model. Crucially, one needs to jointly impute or model all markers of glycemic control that can lead to the initiation of rescue medication. An alternative for hypothesis testing only are rank tests with outcomes from patients 'requiring rescue medication' ranked worst, and non-rescued patients ranked according to final visit values. However, an appropriate ranking of not observed values may be controversial.

Treatment Compliance with Fixed-Dose Combination of Vildagliptin/Metformin in Patients with Type 2 Diabetes Mellitus Inadequately Controlled with Metformin Monotherapy: A 24-Week Observational Study

Objective. To evaluate the differences in treatment compliance with vildagliptin/metformin fixed-dose versus free-dose combination therapy in patients with type 2 diabetes mellitus (T2DM) in Greece. Design. Adult patients with T2DM, inadequately controlled with metformin monotherapy, (850 mg bid), participated in this 24-week, multicenter, observational study. Patients were enrolled in two cohorts: vildagliptin/metformin fixed-dose combination (group A) and vildagliptin metformin free-dose combination (group B). Results. 659 patients were enrolled, 360 were male, with mean BMI 30.1, mean T2DM duration 59.6 months, and mean HbA1c at baseline 8%; 366 patients were assigned to group A and 293 to group B; data for 3 patients was missing. In group A, 98.9% of patients were compliant with their treatment compared to 84.6% of group B. The odds ratio for compliance in group A versus B was (OR) 18.9 (95% CI: 6.2, 57.7; P < 0.001). In group A mean HbA1c decreased from 8.1% at baseline to 6.9% (P < 0.001) at the study end and from 7.9% to 6.8% (P < 0.001) in group B. Conclusions. Patients in group A were more compliant than patients in group B. These results are in accordance with international literature suggesting that fixed-dose combination therapies lead to increased compliance to treatment.

Glycemic effects of vildagliptin and metformin combination therapy in Indian patients with type 2 diabetes: an observational study

BACKGROUND

To analyze the glycemic response of Indian patients with type2 diabetes mellitus (T2DM) to combination therapy with vildagliptin and metformin and compare our data with those of clinical trials.

METHODS

In a retrospective study of the hospital database, the glycemic control of 280 patients with T2DM who were either on a once- or twice-daily regimen of combination therapy with vildagliptin 50 mg and metformin 500 mg was analyzed.

RESULTS

The mean duration of follow-up of the patients was 16.8 months. There was a reduction in fasting plasma glucose (FPG) of 1.52 ± 0.79 and 1.88 ± 0.87 mmol/L in the once- and twice-daily groups, respectively (both P < 0.0001) from baseline to last visit. The reduction in postprandial plasma glucose (PPPG) in the once- and twice-daily groups was 3.98 ± 1.72 and 4.33 ± 1.88 mmol/L, respectively (both P < 0.0001), whereas the reduction in HbA1c was 1.41 ± 1.39% and 1.90 ± 1.49%, respectively (both P < 0.0001). The differences in the reductions achieved in FPG and HbA1c with the two dosing regimens were significant.

CONCLUSION

Although the present retrospective study shows a robust response to the combination of vildagliptin and metformin in Indian patients, more multicenter studies from India with a greater number patients are necessary to confirm this finding.

Systematic review and meta-analysis of efficacy and safety of combinational therapy with metformin and dipeptidyl peptidase-4 inhibitors

Combinational therapies are often required in the management of type 2 diabetes mellitus (T2DM). Among the important candidates, dipeptidyl peptidase-4 inhibitors (DPPIs) and metformin combination (DPPI-MET) have shown promising endeavors. In order to examine the efficacy and safety of such a combination therapy in T2DM patients finding inadequate control with metformin, this systematic review and meta-analysis has been conducted. Literature search was made in multiple electronic databases. Inclusion criteria included; RCTs examining the efficacy and safety of DPPI-MET against placebo-MET or MET-only groups of T2DM patients by observing changes in disease endpoints including HbA1c and FPG, and the length of trial be at least 12 weeks. Mean differences based meta-analyses were performed and heterogeneity assessment was carried out. Nineteen studies were selected and included in the meta-analyses. DPPI-MET significantly improved all disease endpoints and the difference could be noticed up to 2 years in the majority of outcome measures. In comparison with PBO-MET, the DPPI-MET combinational therapy resulted in the percent HbA1c changes from baseline with a mean difference [95% CI] of −0.77 [−0.86, −0.69] in 3-month (P < 0.00001), −0.67 [−0.76, −0.59] in 6-month (P < 0.00001), −0.67 [−0.88, −0.47] in 1-year (P < 0.00001) and −0.36 [−0.53, −0.20] in 2-year trials (P < 0.0003). Reduction in body weight and safety profile in the treated and control groups were not different. A combinational therapy with DPPI and metformin significantly improves diabetes clinical indicators and this effect has been observed for up to 2 years herein. Safety and tolerability of DPPI-MET combination have been found well-manageable with a very similar adverse event profile in both treated and control groups.

Efficacy and safety of dipeptidyl peptidase-4 inhibitors and metformin as initial combination therapy and as monotherapy in patients with type 2 diabetes mellitus: a meta-analysis

AIMS

This meta-analysis was performed to provide an update on the efficacy and safety of dipeptidyl peptidase-4 (DPP-4) inhibitors and metformin as initial combination therapy and as monotherapy in patients with type 2 diabetes mellitus (T2DM).

METHODS

We conducted a search on MEDLINE, Embase and Cochrane Collaborative database for randomized controlled trials (RCTs) of DPP-4 inhibitors and metformin as initial combination therapy or as monotherapy in patients with T2DM by the end of December 2012, using the key words 'alogliptin', 'dutogliptin', 'linagliptin', 'saxagliptin', 'sitagliptin', 'vildagliptin' and 'metformin'. RCTs were selected for meta-analysis if (1) they were RCTs comparing DPP-4 inhibitors plus metformin as initial combination therapy or DPP-4 inhibitor monotherapy to metformin monotherapy, (2) duration of treatment was ≥12 weeks and (3) reported data on haemoglobin A1c (HbA1c) change, fasting plasma glucose (FPG) change, weight change, adverse cardiovascular (CV) events, hypoglycaemia or gastrointestinal adverse events (AEs).

RESULTS

A total of eight RCTs were included. Compared with metformin monotherapy, DPP-4 inhibitors monotherapy was associated with lower reduction in HbA1c level [weighted mean differences (MD) = 0.28, 95% confidence intervals (CIs) (0.17, 0.40), p < 0.00001], lower reduction in FPG level [MD = 0.81, 95% CI(0.60, 1.02), p <0.00001], lower weight loss [MD = 1.51, 95% CI (0.89, 2.13), p < 0.00001], but lower risk of adverse CV events [risk ratio (RR) = 0.36, 95% CI (0.15, 0.85), p = 0.02], lower risk of hypoglycaemia [RR = 0.44, 95% CI (0.27, 0.72), p = 0.001] and lower risk of gastrointestinal AEs [RR = 0.63, 95% CI(0.55, 0.70), p <0.00001]. Compared with metformin monotherapy, DPP-4 inhibitors plus metformin as initial combination therapy was associated with higher reduction in HbA1c level [MD = -0.49, 95% CI (-0.57, -0.40), p < 0.00001], higher reduction in FPG level [MD = -0.80, 95% CI (-0.87, -0.74), p < 0.00001], lower weight loss [MD = 0.44, 95% CI (0.22, 0.67), p = 0.0001]; but was not associated with a further reduction in adverse CV events [RR=0.54, 95% CI (0.25, 1.19), p = 0.13], nor the higher risk of hypoglycaemia [RR = 1.04, 95% CI (0.72, 1.50), p = 0.82], nor the prolonged risk of gastrointestinal AEs [RR = 0.98, 95% CI (0.88, 1.10), p = 0.77].

CONCLUSIONS

DPP-4 inhibitors, which are safe and effective in controlling the blood glucose, may possibly decrease the risk of CV events in patients with T2DM. It could be a credible alternative for T2DM patients who, for some reason, cannot use metformin, or are in high risk of CV exposure. High-quality, large sample and long-term follow-up clinical trails are needed to confirm the long-term conclusions.

Efficacy and safety of combination therapy with vildagliptin and metformin versus metformin up-titration in Chinese patients with type 2 diabetes mellitus: study design and rationale of the vision study

BACKGROUND AND AIM

Limitations of the currently recommended stepwise treatment pathway for type 2 diabetes mellitus (T2DM), especially the failure of monotherapies to maintain good glycemic control, have prompted use of early, more aggressive combination therapies.The VISION study is designed to explore the efficacy and safety of vildagliptin as an add-on to metformin therapy compared with up-titration of metformin monotherapy in Chinese patients with T2DM.

METHODS

VISION, a 24-week, phase 4, prospective, randomized, multicenter, open-label, parallel-group study, will include 3312 Chinese T2DM patients aged ≥18 years who are inadequately controlled (6.5% >HbA1c ≤9%) by metformin (750-1000 mg/day). Eligible patients will be randomized to receive either vildagliptin plus metformin or up-titration of metformin monotherapy (5:1). Patients will also be subgrouped (1:1:1:1) based on their age and body mass index (BMI): <60 years and <24 kg/m²; <60 years and ≥24 kg/m²; ≥60 years and <24 kg/m²; and ≥60 years and ≥24 kg/m².

CONCLUSION

The VISION study will test the hypothesis that early use of combination therapy with vildagliptin and metformin will provide good glycemic control and will be better tolerated than up-titration of metformin monotherapy. The study will also correlate these benefits with age and BMI.

Effects of saxagliptin added to sub-maximal doses of metformin compared with uptitration of metformin in type 2 diabetes: the PROMPT study

OBJECTIVE

The PROMPT study compared efficacy and tolerability of two treatment intensification strategies: adding saxagliptin or uptitrating metformin monotherapy, in patients with type 2 diabetes (T2D) and inadequate glycaemic control on a sub-maximal metformin dose.

RESEARCH DESIGN AND METHODS

In this double-blind, 24-week study, metformin-tolerant patients with T2D on metformin monotherapy were randomised to receive fixed-dose metformin 1500 mg/day, plus either add-on saxagliptin 5 mg/day (SAXA-MET) or a two-step metformin uptitration (MET-UP) to a maximum dose (2500 mg/day).

CLINICAL TRIAL REGISTRATION

NCT01006590.

MAIN OUTCOME MEASURES

Primary: absolute change from baseline in glycated haemoglobin A(1c) (HbA(1c)) (Week 24). Secondary: proportion of patients achieving a therapeutic glycaemic response (Week 24); change from baseline in fasting plasma glucose (Week 24); safety and tolerability. Exploratory analyses comprised three patient-related questionnaires, including the validated 5-dimension Digestive Health Status Index (DHSI).

RESULTS

A total of 286 patients were randomised: (SAXA-MET: 147; MET-UP: 139). Baseline mean (SD) HbA(1c): 7.71 (0.85; SAXA-MET); 7.80 (0.82; MET-UP). Adjusted mean reductions from baseline in HbA(1c) (Week 24): -0.47% (SAXA-MET); -0.38% (MET-UP); mean (95% CI) difference in treatment effect, -0.10% (-0.26, 0.07); p = 0.260. The proportion of patients (95% CI) achieving a therapeutic glycaemic response (HbA(1c) < 7%): 43.8% (34.8, 49.6) (SAXA-MET) vs. 35.0% (29.0, 43.8) (MET-UP). Of the five DHSI domains, mean (95% CI) differences were observed for diarrhoea-predominant score (+0.8 [-2.5, 4.0] vs. +7.9 [4.6, 11.2]) and dysmotility score (-0.5 [-2.0, 1.0] vs. +1.9 [0.3, 3.4]), (SAXA-MET and MET-UP, respectively). The most common adverse event was diarrhoea: 6.1% (SAXA-MET) vs. 12.2% (MET-UP).

CONCLUSIONS

In metformin-tolerant patients with T2D (inadequately controlled on sub-maximal metformin monotherapy), saxagliptin was well tolerated. Although HbA(1c) reduction was not significantly different between treatment groups, the lower occurrence of gastrointestinal symptoms in the SAXA-MET group suggests that saxagliptin add-on treatment may be a suitable alternative treatment strategy to metformin uptitration.

Dipeptidyl peptidase-4 inhibitors: 3 years of experience

According to the latest American Diabetes Association guidelines, lowering glycated hemoglobin (HbA(1c)) to below or around 7% has been shown to reduce microvascular and neuropathic complications of diabetes and, if implemented soon after the diagnosis of diabetes, is associated with long-term reduction in macrovascular disease. Recently a new class of antidiabetes drugs has been developed, dipeptidyl peptidase-4 (DPP-4) inhibitors, which act by inhibiting DPP-4, the enzyme that inactivates glucagon-like peptide-1 (GLP-1). Through the inhibition of DPP-4, DPP-4 inhibitors enhance the effects of GLP-1 and glucose-dependent insulinotropic peptide, increasing glucose-mediated insulin secretion and suppressing glucagon secretion. We conducted a review analyzing clinical efficacy and safety of DPP-4 inhibitors, both alone and in combination with other antidiabetes drugs, including randomized controlled trials about sitagliptin, vildagliptin, saxagliptin, and linagliptin conducted in the latest 15 years. We concluded that, once metformin fails to maintain glycemic control, addition of DPP-4 inhibitors should be the logical choice: they seems to lower HbA(1c) levels by 0.6-0.9 percentage points and to have a comparable effect on HbA(1c) versus the addition of a sulfonylurea or glitazone. They also have positive effects on β-cell function, and they have neutral effects on body weight. Furthermore, DPP-4 inhibitors prevent the risk of hypoglycemia posed by sulfonylureas.

Choosing a gliptin

The treatment of type 2 diabetes mellitus (T2DM) has included the use of metformin and sulfonylurea (SU) as first-line anti-diabetic therapies world over since years. This remains, despite the knowledge that the combination results in a progressive decline in [beta]-cell function and by 3 years up to 50% of diabetic patients can require an additional pharmacological agent to maintain the glycosylated hemoglobin (HbA1c) <7.0% (UKPDS). Gliptins represent a novel class of agents that improve beta cell health and suppress glucagon, resulting in improved post-prandial and fasting hyperglycemia. They function by augmenting the incretin system (GLP-1 and GIP) preventing their metabolism by dipeptidyl peptidase-4 (DPP-4). Not only are they efficacious but also safe (weight neutral) and do not cause significant hypoglycemia, making it a unique class of drugs. This review focuses on gliptins (sitagliptin, vildagliptin, saxagliptin, linagliptin, and alogliptin) discussing pharmacokinetics, pharmacodynamics, efficacy, and safety.

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.

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.

Dipeptidyl peptidase-4 inhibitor for steroid-induced diabetes

The addition of the dipeptidyl peptidase-4 (DDP-4) inhibitor has been reported to achieve greater improvements in glucose metabolism with fewer adverse events compared to increasing the metformin dose in type 2 diabetic patients. We present a patient with steroid-induced diabetes whose blood glucose levels were ameliorated by the use of the DPP-4 inhibitor, showing that the DPP-4 inhibitors may be an effective and safe oral anti-diabetic drug for steroid-induced diabetes.