Vildagliptin enhances islet responsiveness to both hyper- and hypoglycemia in patients with type 2 diabetes

Differential effect of gastric bypass versus sleeve gastrectomy on insulinotropic action of endogenous incretins

OBJECTIVE

Prandial hyperinsulinemia after Roux-en-Y gastric bypass surgery (GB), and to lesser degree after sleeve gastrectomy (SG), has been attributed to rapid glucose flux from the gut and increased insulinotropic gut hormones. However, β-cell sensitivity to exogenous incretin is reduced after GB. This study examines the effect of GB versus SG on prandial glycemia and β-cell response to increasing concentrations of endogenous incretins.

METHODS

Glucose kinetics, insulin secretion rate (ISR), and incretin responses to 50-g oral glucose ingestion were compared between ten nondiabetic participants with GB versus nine matched individuals with SG and seven nonoperated normal glucose tolerant control individuals (CN) with and without administration of 200 mg of sitagliptin.

RESULTS

Fasting glucose and hormonal levels were similar among three groups. Increasing plasma concentrations of endogenous incretins by two- to three-fold diminished prandial glycemia and increased β-cell secretion in all three groups (p < 0.05), but insulin secretion per insulin sensitivity (i.e., disposition index) was increased only in GB (p < 0.05 for interaction). However, plot of the slope of ISR (from premeal to peak values) versus plasma glucagon-like peptide-1 concentration was smaller after GB compared with SG and CN.

CONCLUSIONS

After GB, increasing incretin activity augments prandial β-cell response whereas the β-cell sensitivity to increasing plasma concentrations of endogenous incretin is diminished.

An Imbalance of Pathophysiologic Factors in Late Postprandial Hypoglycemia Post Bariatric Surgery: A Narrative Review

With a rise in obesity and more patients opting for bariatric surgery, it becomes crucial to understand associated complications like postprandial hypoglycemia (PPH). After bariatric surgery, significant changes are seen in insulin sensitivity, beta cell function, glucagon-like peptide 1 (GLP-1) levels, the gut microbiome, and bile acid metabolism. And in a small subset of patients, exaggerated imbalances in these functional and metabolic processes lead to insulin-glucose mismatch and hypoglycemia. The main treatment for PPH involves dietary modifications. For those that do not respond, medications or surgical interventions are considered to reverse some of the imbalances. We present a few case reports of patients that safely tolerated GLP-1 agonists. However, larger randomized control trials are needed to further characterize PPH and understand its treatment.

Insulinotropic effect of endogenous incretins is greater after gastric bypass than sleeve gastrectomy despite diminished beta-cell sensitivity to plasma incretins

BACKGROUND/AIMS

Prandial hyperinsulinemia after Roux-en Y gastric bypass surgery (GB), and to lesser degree after sleeve gastrectomy (SG), has been attributed to rapid glucose flux from the gut and increased insulinotropic gut hormones. However, β-cell sensitivity to exogenous incretin is markedly reduced after GB. This study examines the effect of GB versus SG on prandial glycemia and β-cell response to increasing concentrations of endogenous incretins.

METHODS

Glucose kinetics, insulin secretion rate (ISR), and incretin responses to 50-gram oral glucose ingestion were compared between 10 non-diabetic subjects with GB versus 9 matched individuals with SG and 7 non-operated normal glucose tolerant controls (CN) on two days with and without administration of 200 mg sitagliptin.

RESULTS

Fasting glucose and hormonal levels were similar among 3 groups. Increasing plasma concentrations of endogenous incretins by 2-3-fold diminished post-OGTT glycemia and increased β-cell secretion in all 3 groups (p<0.05), but insulin secretion per insulin sensitivity (i.e., disposition index) was increased only in GB (p<0.05 for interaction). As a result, sitagliptin administration led to hypoglycemia in 3 of 10 GB. Yet, plot of the slope of ISR versus the increase in endogenous incretin concentration was smaller after GB compared to both SG and CN.

CONCLUSION

Augmented glycemic-induced β-cell response caused by enhanced incretin activity is unique to GB and not shared with SG. However, the β-cell sensitivity to increasing concentrations of endogenous incretin is smaller after bariatric surgery, particularly after GB, compared to non-operated controls, indicating a long-term adaptation of gut-pancreas axis after these procedures.

HIGHLIGHTS

What is known?: Glycemic effects of gastric bypass (GB) and sleeve gastrectomy (SG) is attributed to rapid nutrient flux and enhanced insulinotropic effects of gut hormones but β-cell sensitivity to exogenous GLP-1 or GIP is diminished after GB. What the present findings add?: Post-OGTT β-cell sensitivity to enhanced endogenous incretins by DPP4i is markedly reduced in bariatric subjects versus non-operated controls, and yet insulin secretory response (disposition index) is increased leading to hypoglycemia in GB and not SG. Significance?: Blunted sensitivity to GLP-1 may represent β-cell adaptation to massive elevation in GLP-1 secretion following bariatric surgery to protect against hypoglycemia.The differential effect of enhanced concentrations of incretins on post-OGTT insulin response (disposition index) among GB versus SG highlights a distinct adaptive process among the two procedures.Augmented insulinotropic effects of gut hormones on postprandial insulin secretory response after GB despite a reduced beta-cell sensitivity to plasma concentrations of GLP-1 makes a case for non-hormonal mechanisms of GLP-1 action after GB.Better understanding of long-term effects of bariatric surgery on gut-pancreas axis activity is critical in development of GLP-1-based strategies to address glucose abnormalities (both hyperglycemia and hypoglycemia) in these settings.

Metformin Sustained-Release and Vildagliptin Fixed-Dose Combination for Optimizing Glycemic Control: A Review with Real-World Case Reports

(1) Background: There is a high burden of poor glycemic control in the Indian population with type 2 diabetes mellitus (T2DM). Currently, the use of metformin sustained-release (SR)–vildagliptin fixed-dose combination (FDC) is very low as compared to metformin immediate-release (IR)–vildagliptin FDC which is associated with higher adverse events (AEs). Here, we present real-world effectiveness of metformin SR–vildagliptin FDC treatment in patients with T2DM; (2) Methods: This retrospective analysis was carried out from the medical records of adult T2DM patients visiting a single study center in India (December 2020–February 2021). A total of 10 patients (aged ≥20 years) were treated with vildagliptin 50 mg and metformin SR 500 mg FDC for 15 days. The treatment response was assessed by the percentage of time spent in the target glucose range (TIR at baseline and 15 days after treatment); (3) Results: The glycated hemoglobin (HbA1c) levels at baseline varied between 6.5% to 12%. The glycemic control improved in 70% of patients (mean increase in TIR: 18.9%). Treatment adherence was 100%. No gastrointestinal symptoms or AEs were reported; (4) Conclusions: Early intervention with metformin SR–vildagliptin FDC in patients with T2DM can ensure therapy compliance in terms of superior efficacy along with safety and tolerability. Key summary points: Early initiation of combination therapy helps in early achievement of glycemic goals; Early initiation of metformin and vildagliptin FDC results in significant glycemic control with good tolerability and compliance; Metformin SR–vildagliptin FDC has lower adverse events, compared to metformin IR–vildagliptin FDC; A case series of ten patients with T2DM treated with metformin SR–vildagliptin FDC is presented to assess the real-world effectiveness of this combination.

Revisiting the role of glucagon in health, diabetes mellitus and other metabolic diseases

Insulin and glucagon exert opposing effects on glucose metabolism and, consequently, pancreatic islet β-cells and α-cells are considered functional antagonists. The intra-islet hypothesis has previously dominated the understanding of glucagon secretion, stating that insulin acts to inhibit the release of glucagon. By contrast, glucagon is a potent stimulator of insulin secretion and has been used to test β-cell function. Over the past decade, α-cells have received increasing attention due to their ability to stimulate insulin secretion from neighbouring β-cells, and α-cell-β-cell crosstalk has proven central for glucose homeostasis in vivo. Glucagon is not only the counter-regulatory hormone to insulin in glucose metabolism but also glucagon secretion is more susceptible to changes in the plasma concentration of certain amino acids than to changes in plasma concentrations of glucose. Thus, the actions of glucagon also include a central role in amino acid turnover and hepatic fat oxidation. This Review provides insights into glucagon secretion, with a focus on the local paracrine actions on glucagon and the importance of α-cell-β-cell crosstalk. We focus on dysregulated glucagon secretion in obesity, non-alcoholic fatty liver disease and type 2 diabetes mellitus. Lastly, the future potential of targeting hyperglucagonaemia and applying dual and triple receptor agonists with glucagon receptor-activating properties in combination with incretin hormone receptor agonism is discussed.

Role of Dipeptidyl Peptidase 4 Inhibitors in Antidiabetic Treatment

In recent years, important changes have occurred in the field of diabetes treatment. The focus of the treatment of diabetic patients has shifted from the control of blood glucose itself to the overall management of risk factors, while adjusting blood glucose goals according to individualization. In addition, regulators need to approve new antidiabetic drugs which have been tested for cardiovascular safety. Thus, the newest class of drugs has been shown to reduce major adverse cardiovascular events, including sodium-glucose transporter 2 (SGLT2) and some glucagon like peptide 1 receptor (GLP1) analog. As such, they have a prominent place in the hyperglycemia treatment algorithms. In recent years, the role of DPP4 inhibitors (DPP4i) has been modified. DPP4i have a favorable safety profile and anti-inflammatory profile, do not cause hypoglycemia or weight gain, and do not require dose escalation. In addition, it can also be applied to some types of chronic kidney disease patients and elderly patients with diabetes. Overall, DPP4i, as a class of safe oral hypoglycemic agents, have a role in the management of diabetic patients, and there is extensive experience in their use.

A prospective multicentre open label study to assess effect of Teneligliptin on glycemic control through parameters of time in range (TIR) Metric using continuous glucose monitoring (TOP-TIR study)

BACKGROUND AND AIMS

Continuous glucose monitoring (CGM) has been effective in assessing glycemic variability in diabetic patients. This study aims at assessing the effect of Teneligliptin using ambulatory glucose profile (AGP) indicators.

METHODS

A prospective, multicentre, open label study enrolling 59 type 2 diabetes patients between 18 and 65 years age was done between November 2020-May 2021. Patients were administered Teneligliptin 20 mg once daily, in addition to Metformin. The study included pre-treatment and two post-treatment phases. The data on time in range (TIR) and other AGP indicators of glycemic variability were obtained on each patient in all the three study phases and analysed to understand the effect of Teneligliptin on glycemic variability. Safety evaluation was done based on vital and biochemical parameters.

RESULTS

The percent TIR in post-treatment phase I was significantly higher than the pre-treatment phase (p < 0.0001), and was maintained till the end of phase II (p = 0.037). There was significant lowering of time above range (≥180 mg/dL) in the phase I (p = 0.003), which was maintained in phase II (p = 0.043), suggesting better control over hyperglycemic state. The reduction in mean glucose level in phase I and II was also significant compared to baseline (p = 0.003 and p = 0.023 respectively). The glucose variability percent and glucose management indicator also showed significant lowering in both the phases.

CONCLUSIONS

Teneligliptin addition to patients uncontrolled on Metformin monotherapy significantly reduced glycemic variability, as well showed significant glycemic improvement. Since this study was a single arm study, a comparative study with other DPP-4 inhibitors is needed.

Effects on weight loss and glycemic control with SAR441255, a potent unimolecular peptide GLP-1/GIP/GCG receptor triagonist

Unimolecular triple incretins, combining the activity of glucagon-like peptide-1 (GLP-1), glucose-dependent insulinotropic polypeptide (GIP), and glucagon (GCG), have demonstrated reduction in body weight and improved glucose control in rodent models. We developed SAR441255, a synthetic peptide agonist of the GLP-1, GCG, and GIP receptors, structurally based on the exendin-4 sequence. SAR441255 displays high potency with balanced activation of all three target receptors. In animal models, metabolic outcomes were superior to results with a dual GLP-1/GCG receptor agonist. Preclinical in vivo positron emission tomography imaging demonstrated SAR441255 binding to GLP-1 and GCG receptors. In healthy subjects, SAR441255 improved glycemic control during a mixed-meal tolerance test and impacted biomarkers for GCG and GIP receptor activation. Single doses of SAR441255 were well tolerated. The results demonstrate that integrating GIP activity into dual GLP-1 and GCG receptor agonism provides improved effects on weight loss and glycemic control while buffering the diabetogenic risk of chronic GCG receptor agonism.

Effect of dipeptidyl peptidase-4 inhibitors on postprandial glucagon level in patients with type 2 diabetes mellitus: A systemic review and meta-analysis

AIMS

Hyperglucagonemia occurs in the pathogenesis of type 2 diabetes mellitus (T2DM). In this meta-analysis, we summarized the effects of DPP4 inhibitors on glucagon levels in patients with T2DM.

MATERIALS AND METHODS

Randomized controlled trials (RCTs) comparing the influence of DPP4 inhibitors on circulating glucagon levels with placebo or other oral antidiabetic drugs (OADs) in patients with T2DM were identified by searches of Medline (PubMed), Embase (Ovid), and CENTER (Cochrane Library). Only studies reporting changes in glucagon level presented as total area under the curve (AUC_glucagon) using a meal or oral glucose tolerance test were included. Results were combined using a random-effects model that incorporated potential heterogeneity among the included studies.

RESULTS

A total of 36 RCTs with moderate to high quality were included. Overall, the numbers of T2DM patients included for the meta-analyses comparing DPP4 inhibitors with placebo and other OADs were 4266 and 1652, respectively. Compared to placebo, DPP4 inhibitors significantly reduced circulating glucagon levels (standard mean difference [SMD]: -0.32, 95% CI: -0.40 to -0.24, P<0.001; I^{2 =} 28%). Analysis of subgroups revealed that study characteristics had no significant effect on results, such as study design (parallel group or crossover), number of patients, mean patient age, proportion of men, baseline HbA1c, duration of diabetes, background therapy, treatment duration, or methods for glucagon measurement (all P for subgroup differences >0.05). Moreover, DPP4 inhibitors significantly reduced glucagon levels compared to other OADs (SMD: -0.35, 95% CI: -0.53 to -0.16, P<0.001; I² = 66%), and the reduction in glucagon was greater in comparison with insulin secretagogues than in comparison with non-insulin secretagogues (P for subgroup difference =0.03).

SYSTEMATIC REVIEW REGISTRATION

https://inplasy.com/, identifier INPLASY202280104.

CONCLUSIONS

DPP4 inhibitors are effective at reducing the circulating postprandial glucagon level in T2DM patients.

Long-Term Glycaemic Durability of Early Combination Therapy Strategy versus Metformin Monotherapy in Korean Patients with Newly Diagnosed Type 2 Diabetes Mellitus

We assessed the glycaemic durability with early combination (EC; vildagliptin+metformin [MET], n=22) versus MET monotherapy (n=17), among newly-diagnosed type 2 diabetes mellitus (T2DM) enrolled (between 2012 and 2014) in the VERIFY study from Korea (n=39). Primary endpoint was time to initial treatment failure (TF) (glycosylated hemoglobin [HbA1c] ≥7.0% at two consecutive scheduled visits after randomization [end of period 1]). Time to second TF was assessed when both groups were receiving and failing on the combination (end of period 2). With EC the risk of initial TF significantly reduced by 78% compared to MET (n=3 [15%] vs. n=10 [58.7%], P=0.0228). No secondary TF occurred in EC group versus five patients (29.4%) in MET. Patients receiving EC treatment achieved consistently lower HbA1c levels. Both treatment approaches were well tolerated with no hypoglycaemic events. In Korean patients with newly diagnosed T2DM, EC treatment significantly and consistently improved the long-term glycaemic durability as compared with MET.

A Comprehensive Review and Perspective on Natural Sources as Dipeptidyl Peptidase-4 Inhibitors for Management of Diabetes

Type 2 diabetes mellitus (T2DM) is an increasing global public health problem, and its prevalence is expected to rise in coming decades. Dipeptidyl peptidase-4 (DPP-4) is a therapeutic target for the management of T2DM, and its inhibitors prevent the degradation of glucose-dependent insulinotropic peptide and glucagon-like peptide 1, and thus, maintain their endogenous levels and lower blood glucose levels. Various medicinal plant extracts and isolated bioactive compounds exhibit DPP-4 inhibitory activity. In this review, we discussed different natural sources that have been shown to have anti-diabetic efficacy with a particular emphasis on DPP-4 inhibition. Furthermore, the effect of DPP-4 inhibition on pancreatic beta cell function, skeletal muscle function, and the glucose-lowering mechanisms were also discussed. We believe that scientists looking for novel compounds with therapeutic promise against T2DM will be able to develop antidiabetic drugs using these natural sources.

Altered hormonal and autonomic nerve responses to hypo- and hyperglycaemia are found in overweight and insulin-resistant individuals and may contribute to the development of type 2 diabetes

AIMS/HYPOTHESIS

Results from animal models and some clinical work suggest a role for the central nervous system (CNS) in glucose regulation and type 2 diabetes pathogenesis by modulation of glucoregulatory hormones and the autonomic nervous system (ANS). The aim of this study was to characterise the neuroendocrine response to various glucose concentrations in overweight and insulin-resistant individuals compared with lean individuals.

METHODS

Overweight/obese (HI, n = 15, BMI ≥27.0 kg/m²) and lean (LO, n = 15, BMI <27.0 kg/m²) individuals without diabetes underwent hyperinsulinaemic euglycaemic-hypoglycaemic clamps and hyperglycaemic clamps on two separate occasions with measurements of hormones, Edinburgh Hypoglycaemic Symptom Scale (ESS) score and heart rate variability (HRV). Statistical methods included groupwise comparisons with Mann-Whitney U tests, multilinear regressions and linear mixed models between neuroendocrine responses and continuous metabolic variables.

RESULTS

During hypoglycaemic clamps, there was an elevated cortisol response in HI vs LO (median ΔAUC 12,383 vs 4793 nmol/l × min; p = 0.050) and a significantly elevated adrenocorticotropic hormone (ACTH) response in HI vs LO (median ΔAUC 437.3 vs 162.0 nmol/l × min; p = 0.021). When adjusting for clamp glucose levels, obesity (p = 0.033) and insulin resistance (p = 0.009) were associated with elevated glucagon levels. By contrast, parasympathetic activity was less suppressed in overweight individuals at the last stage of hypoglycaemia compared with euglycaemia (high-frequency power of HRV, p = 0.024). M value was the strongest predictor for the ACTH and P_HF responses, independent of BMI and other variables. There was a BMI-independent association between the cortisol response and ESS score response (p = 0.024). During hyperglycaemic clamps, overweight individuals displayed less suppression of glucagon levels (median ΔAUC -63.4% vs -73.0%; p = 0.010) and more suppression of sympathetic relative to parasympathetic activity (low-frequency/high-frequency power, p = 0.011).

CONCLUSIONS/INTERPRETATION

This study supports the hypothesis that altered responses of insulin-antagonistic hormones and the ANS to glucose fluctuations occur in overweight and insulin-resistant individuals, and that these responses are probably partly mediated by the CNS. Their potential role in development of type 2 diabetes needs to be addressed in future research. Graphical abstract.

Impact of Ramadan Diurnal Intermittent Fasting on Hypoglycemic Events in Patients With Type 2 Diabetes: A Systematic Review of Randomized Controlled Trials and Observational Studies

Ramadan is the 9th month of the lunar calendar during which Muslims abstain from food and drink between dawn and sunset for 30 consecutive days. Ramadan fasting is observed by all healthy Muslim adults, as well many Muslims with type 2 diabetes (T2DM). Hypoglycemic events (HE) are a serious complication associated with diabetes management and are associated with increased cardiovascular disease risk. Conflicting results have been reported concerning the incidence of HE among people with T2DM observing Ramadan fasting. This review summarizes available scientific evidence on the occurrence of HE and the effects of different moderators on the incidence of HE among patients with T2DM during Ramadan. We conducted a systematic review of available observational studies and randomized controlled trials (RCTs) for patients with T2DM who fasted during Ramadan, with HE as the primary outcome. Ten databases were searched for relevant studies from inception until October 31, 2020. In total, 68 studies (35 RCTs and 33 observational studies) met the inclusion criteria. Non-sulfonylureas hypoglycemic medications showed superior effects in lowering the incidence of HE over sulfonylureas hypoglycemic medications. Variable moderators were associated with experiencing HE during Ramadan in both observational studies and RCTs, including sex, geographical location, body anthropometric indicators, season, dietary behaviors, fasting duration, time since diagnosis, and pre-fasting education. This comprehensive systematic review covered the largest number of observational and clinical studies investigating the impact of Ramadan on HE among patients with T2DM. The study highlights the significance of different moderators that influence the effect of Ramadan fasting on HE, including dietary behaviors, fasting time duration, sex, season, country, pre-fasting education, age, and time since diagnosis. The study also highlighted the impact of different hypoglycemic medications on HE and noted the superiority of non-sulfonylureas over sulfonylureas hypoglycemic medications in lowering the risk for hypoglycemia in people with T2DM during Ramadan fasting.

Effects of DPP-4 Inhibitors on Blood Glucose Variability in Japanese Patients with Type 2 Diabetes on Maintenance Hemodialysis: A Prospective Observational Exploratory Study

INTRODUCTION

The precise blood glucose (BG) profile of hemodialysis patients is unclear, as is the effectiveness of dipeptidyl peptidase-4 (DPP-4) inhibitors in hemodialysis patients with type 2 diabetes. Here, we used continuous glucose monitoring (CGM) to evaluate BG variability in these patients and to assess the efficacy of DPP-4 inhibitors, particularly during hemodialysis sessions and at nighttime (UMIN000012638).

METHODS

We examined BG profiles using CGM in 31 maintenance hemodialysis patients with type 2 diabetes. Differences between patients with and without DPP-4 inhibitors (n = 15 and 16, respectively) were analyzed using a linear mixed-effects model to assess changes in glucose levels in 5-min intervals.

RESULTS

The model revealed that DPP-4 inhibitor use was significantly associated with suppression of a rapid drop in glucose levels, both with and without adjustment for BG levels at the start of hemodialysis. Moreover, the model revealed that the two groups differed significantly in the pattern of changes in BG levels from 0:00 to 6:55 am. DPP-4 inhibitors suppressed the tendency for subsequent nocturnal hypoglycemia.

CONCLUSIONS

This prospective observational exploratory study showed that DPP-4 inhibitors could suppress BG variability during hemodialysis sessions as well as subsequent nocturnal changes in patients with type 2 diabetes.

TRIAL REGISTRATION

ClinicalTrials.gov identifier, UMIN000012638.

Dipeptidyl peptidase 4 inhibitors in the treatment of type 2 diabetes mellitus

Dipeptidyl peptidase 4 inhibitors (DPP4i) have been available for treating type 2 diabetes mellitus since 2006. Although they are a diverse group, DPP4i are all small, orally available molecules that interact with the catalytic site of DPP4 without disturbing any of its other known functions, including its effects on the immune system. DPP4i have no intrinsic glucose-lowering activity, so their efficacy as anti-diabetic agents is related directly to their ability to inhibit DPP4 activity and is mediated through the effects of the substrates they protect. Of these, the incretin hormone, glucagon-like peptide 1, is probably the most important. As the effects of glucagon-like peptide 1 are glucose-dependent, the risk of hypoglycaemia with DPP4i is low. Class effects, which are directly related to the mechanism of action, are common to all DPP4i; these include their overall good safety profile and tolerability, as well as their efficacy in improving glycaemic control, but also, potentially, a small increased risk of acute pancreatitis. Compound-specific effects are those related to their differing chemistries and/or pharmacokinetic profiles. These compound-specific effects could affect the way in which individual DPP4i are used therapeutically and potentially explain off-target adverse effects, such as hospitalization for heart failure, which is seen only with one DPP4i. Overall, DPP4i have a favourable therapeutic profile and are safe and effective in the majority of patients with type 2 diabetes mellitus.

Short-term renal and metabolic effects of low dose vildagliptin treatment added-on insulin therapy in non-proteinuric patients with type 2 diabetes: open-label randomized prospective study

Objective The aim of this randomized comparative study was to assess renal and metabolic effects of vildagliptin in insulin-treated type 2 diabetes (T2DM) patients without overt chronic kidney disease. Subjects and methods We randomized 47 insulin-treated non-proteinuric patients with satisfactory controlled T2DM and estimated glomerular filtration rate (eGFR) ≥ 60 mL/min/1.73m 2 either to continue insulin therapy (control) or to receive combined insulin-vildagliptin treatment (VIG group). We assessed eGFR using serum creatinine (eGFRcreat), cystatin C (eGFRcys), and both (eGFRcreat-cys), and urinary creatinine-adjusted excretion of albumin (UACR), type IV collagen (uCol IV/Cr), and neutrophil gelatinase-associated lipocalin (uNGAL/Cr) at baseline and after 6 months of treatment. Results Study groups were comparable in terms of age and sex (60.1 ± 6.1 years and 42.9% men in control group vs. 60.8 ± 5.2 years and 39.1% in VIG group). After 6 months of treatment, there were no significant changes in main assessed parameters in control group. VIG group demonstrated significant decrease in HbA1c, diastolic blood pressure, frequency of hypoglycemia, and high-sensitivity C-reactive protein level as compared to the changes in control group. While eGFRcreat, UACR, and uNGAL/Cr showed no significant changes after vildagliptin addition, eGFRcys, eGFRcreat-cys, and uCol IV/Cr changed significantly in comparison with control group (+7.0% [3.7;13.3]; +5.1% [1.4;8.5]; -32,8% [-55.8;-24.4], respectively, p < 0.01 each). Correlation and regression analysis revealed glucose-independent pattern of these changes. Conclusion Addition of vildagliptin to ongoing insulin therapy in patients with T2DM was associated with a reduction in uCol IV/Cr and an increase in eGFRcys and eGFRcreat-cys, independent of T2DM control parameters.

Metabolism of GIP and the contribution of GIP to the glucose-lowering properties of DPP-4 inhibitors

Glucose-dependent insulinotropic polypeptide (GIP) is a gastrointestinal hormone with insulinotropic and glucagonotropic actions, and is believed to be the more physiologically important incretin hormone in healthy humans. Together with the other incretin hormone, glucagon-like peptide-1 (GLP-1), it plays an important role in regulating glucose homeostasis. Both GLP-1 and GIP are substrates of the enzyme dipeptidyl peptidase-4 (DPP-4), and DPP-4 inhibitors, which potentiate their effects on glycaemic control, are now used to treat type 2 diabetes (T2D). This review describes how post-translational processing of the GIP precursor molecule and post-release degradation of the secretory products give rise to multiple isoforms of GIP, some, but not all of which are biologically active, and discusses how this impacts upon their measurement by immunological- and bioassay-based methods. DPP-4 inhibitors reduce degradation of GIP, and although the insulinotropic effects of GIP are impaired in patients with T2D, they can be at least partially restored if glycaemic control is improved. Therefore, given that studies with incretin receptor antagonists indicate that not all of the glucose-lowering effects of DPP-4 inhibition can be accounted for by GLP-1 alone, evidence supports the notion that GIP may play a role in mediating the anti-hyperglycaemic effects of DPP-4 inhibition, while its glucagonotropic actions at lower glucose levels may contribute to the low risk of hypoglycaemia associated with DPP-4 inhibitors.

Vildagliptin, an Anti-diabetic Drug of the DPP-4 Inhibitor, Induces Vasodilation via Kv Channel and SERCA Pump Activation in Aortic Smooth Muscle

This study investigated vildagliptin-induced vasodilation and its related mechanisms using phenylephrine induced precontracted rabbit aortic rings. Vildagliptin induced vasodilation in a concentration-dependent manner. Pretreatment with the large-conductance Ca²⁺-activated K⁺ channel blocker paxilline, ATP-sensitive K⁺ channel blocker glibenclamide, and inwardly rectifying K⁺ channel blocker Ba²⁺ did not affect the vasodilatory effects of vildagliptin. However, application of the voltage-dependent K⁺ (Kv) channel inhibitor 4-aminopyridine significantly reduced the vasodilatory effects of vildagliptin. In addition, application of either of two sarcoplasmic/endoplasmic reticulum Ca²⁺-ATPase (SERCA) inhibitors, thapsigargin or cyclopiazonic acid, effectively inhibited the vasodilatory effects of vildagliptin. These vasodilatory effects were not affected by pretreatment with adenylyl cyclase, protein kinase A (PKA), guanylyl cyclase, or protein kinase G (PKG) inhibitors, or by removal of the endothelium. From these results, we concluded that vildagliptin induced vasodilation via activation of Kv channels and the SERCA pump. However, other K⁺ channels, PKA/PKG-related signaling cascades associated with vascular dilation, and the endothelium were not involved in vildagliptin-induced vasodilation.

Efficacy and safety of gemigliptin as add-on therapy to insulin, with or without metformin, in patients with type 2 diabetes mellitus (ZEUS II study)

The objective of this study was to evaluate the efficacy and safety of gemigliptin added to a stable dose of insulin alone or of insulin in combination with metformin in patients with type 2 diabetes mellitus. After a two-week run-in period, patients were randomized 2:1 to receive gemigliptin 50 mg or placebo once daily as add-on to background therapy with insulin or insulin plus metformin for 24 weeks. The primary endpoint was change in haemoglobin A1c (HbA1c) from baseline at Week 24. Baseline characteristics were similar between the gemigliptin (n = 188) and placebo (n = 95) groups in terms of HbA1c (8.1%). At Week 24, the gemigliptin group showed a statistically significant reduction in mean HbA1c from baseline as compared with placebo (between-group mean difference, -0.7% [95% CI, -0.9% to -0.4%]; P-value < 0.0001). The incidence of overall adverse events and the number of hypoglycaemic adverse events were similar between the study groups. Gemigliptin added to insulin alone or to insulin in combination with metformin resulted in superior glycaemic control compared to that in the placebo group and was well tolerated for 24 weeks in patients with type 2 diabetes mellitus, without causing weight gain or increasing the incidence of hypoglycaemia.

Incretin-based medications (GLP-1 receptor agonists, DPP-4 inhibitors) as a means to avoid hypoglycaemic episodes

Hypoglycaemia is common in both type 1 and type 2 diabetes and has both acute and long-term consequences. Therefore, a key to proper glucose-lowering therapy in diabetes is to avoid or prevent hypoglycaemia. Incretin therapy (DPP-4 inhibitors and GLP-1 receptor agonists) offers an advantage in this respect, because it reduces glucose with a low risk of hypoglycaemia, both in monotherapy and in combination with other therapies. The reason for this low risk of hypoglycaemia is the glucose dependency of action of incretin therapy and the sustainment of glucose counter-regulatory hormone responses to hypoglycaemia, in particular the glucagon response. Incretin therapy is also associated with a low risk of hypoglycaemia in patient groups which are especially vulnerable and susceptible for hypoglycaemia, e.g., subjects with renal impairment, elderly subjects and subjects with on-going insulin therapy. This review summarizes how incretin therapy may meet the challenges of hypoglycaemia and suggests that incretin therapy is a therapy of choice to avoid hypoglycaemia, both in the general diabetes population and in subjects with increased risk or vulnerability for hypoglycaemia.

DPP-4 Inhibition and the Path to Clinical Proof

In the 1990s it was discovered that the enzyme dipeptidyl peptidase-4 (DPP-4) inactivates the incretin hormones glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP). DPP-4 inhibition results in raised levels of the two incretin hormones which in turn result in lowering of circulating glucose through stimulation of insulin secretion and inhibition of glucagon secretion. Since then, several small orally available molecules have been developed with DPP-4 inhibitory action. Early studies in the 1990s showed that the DPP-4 inhibitors improve glycemia in animals. Subsequent clinical studies during the 2000s showed a glucose-lowering action of DPP-4 inhibitors also in human subjects with type 2 diabetes. This action was seen when DPP-4 inhibitors were used both as monotherapy and as add-on to other therapies, i.e., metformin, sulfonylureas, tiazolidinediones or exogenous insulin. The DPP-4 inhibitors were also found to have a low risk of adverse events, including hypoglycemia. Five of the DPP-4 inhibitors (sitagliptin, vildagliptin, alogliptin, saxagliptin and linagliptin) were approved by regulatory authorities and entered the market between 2006 and 2013. DPP-4 inhibitors have thereafter undergone long-term cardiovascular outcome trials, showing non-inferiority for risk of major acute cardiovascular endpoints. Also the risk of other potential adverse events is low in these long-term studies. DPP-4 inhibitors are at present included in guidelines as a glucose-lowering concept both as monotherapy and in combination therapies. This article summarizes the development of the DPP-4 inhibition concept from its early stages in the 1990s. The article underscores that the development has its basis in scientific studies on pathophysiology of type 2 diabetes and the importance of targeting the islet dysfunction, that the development has been made possible through academic science in collaboration with the research-oriented pharmaceutical industry, and that the development of a novel concept takes time and requires focused efforts, persistence and long-term perserverance.

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 β-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 β-cell function that is likely secondary to the improved metabolic state. Although there was no evidence of restoration of β-cell mass, the preponderance of the vildagliptin data does indicate that for at least 2 years β-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 β 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.

Relationship Between Fasting Plasma Glucagon Level and Renal Function-A Cross-Sectional Study in Individuals With Type 2 Diabetes

Background and Aim

The kidney is the main site for glucagon clearance. However, a recent study showed that hyperglucagonemia in patients with end-stage renal disease might not be caused by full-length intact glucagon. Additionally, the relationship between glucagon and renal function in early-stage chronic kidney disease (CKD) has not yet been characterized. We studied the association of fasting glucagon with renal function across a wide range of glomerular filtration rates (GFRs) in participants with type 2 diabetes.

Participants and Methods

326 participants with type 2 diabetes and renal function spanning CKD stage 1 to 5 were included in the present cross-sectional study. Fasting full-length plasma glucagon was quantified using a newly developed ELISA (Mercodia AB, Uppsala, Sweden).

Results

The fasting plasma glucagon level was elevated linearly from CKD stage 1 to 5 [from a median of 2.5 pM (interquartile range, 1.4 to 4.7) in CKD 1 to a median of 8.3 pM (interquartile range, 5.9 to 12.8) in CKD 5; P for trend < 0.0001], from as early as CKD stage 2 compared with that in stage 1 (Bonferroni-corrected P < 0.0001). The estimated GFR and homeostatic model of assessment–insulin resistance were the main determinants of the fasting glucagon level. These explained 14.3% and 10.3% of the glucagon variance, respectively. Albuminuria was not associated with fasting glucagon after adjustment for estimated GFR.

Conclusions

Fasting full-length glucagon was elevated linearly with the deterioration in renal function in individuals with type 2 diabetes, even in those with early CKD. In addition to renal function, insulin sensitivity was also a main determinant of glucagon variance.

Effects on the glucagon response to hypoglycaemia during DPP-4 inhibition in elderly subjects with type 2 diabetes: A randomized, placebo-controlled study

AIMS

Maintainance of glucagon response to hypoglycaemia is important as a safeguard against hypoglycaemia during glucose-lowering therapy in type 2 diabetes. During recent years, DPP-4 (dipeptidyl peptidase-4) inhibition has become more commonly used in elderly patients. However, whether DPP-4 inhibition affects the glucagon response to hypoglycaemia in the elderly is not known and was the aim of this study.

METHODS

In a single-centre, double-blind, randomized, placebo-controlled crossover study, 28 subjects with metformin-treated type 2 diabetes (17 male, 11 female; mean age, 74 years [range 65-86]; mean HbA1c, 51.5 mmol/mol [6.9%]) received sitagliptin (100 mg once daily) as add-on therapy or placebo for 4 weeks with a 4-week washout period in between. After each treatment period, the subjects underwent a standard breakfast test, followed by a 2-step hyperinsulinaemic hypoglycaemic clamp (target 3.5 and 3.0 mmol/L), followed by lunch.

RESULTS

Glucagon levels after breakfast and lunch, and the glucagon response at 3.5 mmol/L, were lower after sitagliptin than after placebo. However, the glucagon response to hypoglycaemia at 3.1 mmol/L did not differ significantly between the two. Similarly, the noradrenaline, adrenaline and cortisol responses were lower with sitagliptin than with placebo at 3.5 mmol/L, but not at 3.1 mmol/L glucose. Responses in pancreatic polypeptide did not differ between the two.

CONCLUSIONS

Elderly subjects with metformin-treated type 2 diabetes have lower glucagon levels at 3.5 mmol/L glucose, but maintain the glucagon response to hypoglycaemia at 3.1 mmol/L during DPP-4 inhibition, which safeguards against hypoglycaemia and may contribute to decreasing the risk of hypoglycaemia by DPP-4 inhibition in this age group.

Different glucagon effects during DPP-4 inhibition versus SGLT-2 inhibition in metformin-treated type 2 diabetes patients

AIMS

Previous studies have shown that dipeptidyl peptidase (DPP)-4 inhibition lowers glucagon levels whereas sodium-glucose co-transporter 2 (SGLT-2) inhibition increases them. This study evaluated the extent of these opposite effects in a direct comparative head-to-head study.

METHODS

In a single-centre, randomized study with a cross-over design, 28 metformin-treated patients with type 2 diabetes (T2D) (mean age, 63 years; baseline HbA1c, 6.8%) were treated with vildagliptin (50 mg twice daily) or dapagliflozin (10 mg once daily) for 2 weeks, with a 4-week wash-out period between the two separate treatments. After each treatment period, a meal test was undertaken, with measurements of islet and incretin hormones and 4-hour area under the curve (AUC) levels were estimated.

RESULTS

Fasting glucagon (35.6 ± 2.5 vs 39.4 ± 3.4 pmoL/L; P = .032) and postprandial glucagon (4-hour AUC_glucagon , 32.1 ± 2.3 vs 37.5 ± 2.7 nmoL/L min; P = .001) were ~15% lower after vildagliptin compared to dapagliflozin treatment. This was associated with stronger early (15 minute) C-peptide response and higher 4-hour AUC_C-peptide (P < .010), higher 4-hour AUC of the intact form of glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) (P < .001) and lower 4-hour AUC of total GIP and GLP-1 (P < .001).

CONCLUSION

Treatment with DPP-4 inhibition with vildagliptin results in 15% lower fasting and postprandial glucagon levels compared to SGLT-2 inhibition with dapagliflozin. DPP-4 inhibition also induces more rapid insulin secretion and higher levels of intact incretin hormones, resulting in stronger feedback inhibition of incretin hormone secretion than SGLT-2 inhibition.

Efficacy and safety of combination therapy with an α-glucosidase inhibitor and a dipeptidyl peptidase-4 inhibitor in patients with type 2 diabetes mellitus: A systematic review with meta-analysis

AIMS/INTRODUCTION

The combination of dipeptidyl peptidase-4 (DPP4) inhibitors and α-glucosidase inhibitors (AGIs) might provide an additive or synergistic glucose-lowering effect, as they have a complementary mode of action. In the present study, we examined the efficacy and safety of the addition of a DPP4 inhibitor to patients with type 2 diabetes inadequately controlled with an AGI.

MATERIALS AND METHODS

We carried out an electronic search of MEDLINE, EMBASE, the Cochrane Library and Clinicaltrials.gov through October 2016. Randomized controlled trials written in English that compared DPP4 inhibitors plus AGI (DPP4i/AGI) and placebo plus AGI (PCB/AGI) in patients with type 2 diabetes were selected. Data on the study characteristics, efficacy and safety outcomes were extracted, and the risk of potential biases was assessed. The efficacy and safety of DPP4i/AGI and PCB/AGI were compared.

RESULTS

Of 756 potentially relevant published articles and 40 registered trials, five studies including 845 patients randomized to DPP4i/AGI and 832 patients randomized to PCB/AGI were included for meta-analysis. Compared with PCB/AGI, DPP4i/AGI showed a greater reduction in glycated hemoglobin (weighted mean difference -1.2%, 95% confidence interval -1.6 to -0.8), fasting plasma glucose and 2-h postprandial plasma glucose levels, with no increase in bodyweight. The risks of hypoglycemia and gastrointestinal adverse events were similar between DPP4i/AGI and PCB/AGI.

CONCLUSIONS

The addition of a DPP4 inhibitor to patients with type 2 diabetes inadequately controlled with an AGI achieved better glycemic control without further increasing the risk of weight gain and hypoglycemia.

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.

Effectiveness of sitagliptin in a patient with late dumping syndrome after total gastrectomy

An 83-year-old man developed hypoglycemia after undergoing total gastrectomy for gastric cancer in 200X-4. The patient was admitted to our hospital in May 200X and placed on continuous glucose monitoring (CGM). Glycemic excursions were examined while on 3-meal/day (1700kcal) and 6-meal/day (1800kcal) diets. Oxyhyperglycemia followed about 2h later by a sudden drop in glucose levels was seen with both regimens. These findings were consistent with late dumping syndrome. CGM was continued, oral miglitol at 150mg/day or sitagliptin at 50mg/day was started, and glycemic excursions were compared. Results were similar for both drugs, with reductions in postprandial glucose elevations. Meal tolerance testing 3 months after oral sitagliptin, compared to before starting treatment, showed reductions in both early postprandial hyperglycemia and insulin hypersecretion. These findings suggest that DPP-4 inhibitors such as sitagliptin may be effective for treating post-gastrectomy late dumping syndrome.

Combination of sodium-glucose cotransporter 2 inhibitor and dipeptidyl peptidase-4 inhibitor in type 2 diabetes: a systematic review with meta-analysis

Sodium glucose cotransporter 2 (SGLT2) inhibitors and dipeptidyl peptidase-4 (DPP4) inhibitors have complementary mode of action. For the meta-analysis comparing the efficacy and safety between SGLT2 inhibitor plus DPP4 inhibitor (SGLT2i/DPP4i) and placebo plus DPP4 inhibitor (PCB/DPP4i) in patients with type 2 diabetes mellitus (T2DM), we selected randomized controlled trials from electronic databases by predefined criteria. The primary outcome of interest was the change in glycated hemoglobin A1c (HbA1c) from baseline. Of 605 potentially relevant studies, 7 eligible RCTs comprising 2,082 patients were included.SGLT2i/DPP4i showed a greater reduction in HbA1c (weighted mean difference −0.6%, 95% CI −0.7 to −0.5%), fasting plasma glucose, 2 h postprandial plasma glucose, and body weight compared to PCB/DPP4i. The risk of hypoglycemia increased in SGLT2i/DPP4i compared to that in PCB/DPP4i only when insulin or sulfonylureas were included as a background therapy. The risk of urinary tract infection was not increased in SGLT2i/DPP4i; however, the risk of genital infection increased upon adding SGLT2 inhibitors to pre-existing DPP4 inhibitors. In conclusion, compared to PCB/DPP4i, SGLT2i/DPP4i achieved better glycemic control and greater weight reduction without increasing the risk of hypoglycemia and urinary tract infection in patients with inadequately controlled T2DM.

A review of dipeptidyl peptidase-4 inhibitors. Hot topics from randomized controlled trials

The first clinical study to investigate effects of dipeptidyl peptidase-4 (DPP-4) inhibition was published in 2002, and since then, numerous randomized controlled trials (RCTs) have shown that DPP-4 inhibitors are efficacious, safe and well-tolerated. This review will focus upon RCTs which have investigated DPP-4 inhibitors in patient groups which are often under-represented or excluded from typical phase 3 clinical trials. Large cardiovascular (CV) safety outcome trials in patients with established CV disease have confirmed that DPP-4 inhibitors are not associated with any additional CV risk in these already-at-high-risk individuals, while raising awareness of any uncommon adverse events, such as heart failure hospitalization seen in one of the trials. Studies in patients with kidney disease have shown DPP-4 inhibitors to be efficacious without increasing the risk of hypoglycaemia, irrespective of the degree of renal impairment, while data from the large CV trials as well as smaller RCTs have even pointed towards potential renoprotective effects such individuals. The use of DPP-4 inhibitors with insulin when therapy requires intensification may be beneficial without affecting the incidence or severity of hypoglycaemia, with these effects also being replicated in patients with chronic kidney disease, for whom other agents may not be suitable. Attention is now turning towards exploring the potential utility of DPP-4 inhibitors in other circumstances, including for in-hospital management of hyperglycaemia and in other metabolic disorders. Together, these RCTs raise the possibility that in the future, DPP-4 inhibitors may have a broader use which may extend beyond glycaemic control in the typical type 2 diabetes mellitus (T2DM) patient seen in general practice and may encompass conditions other than T2DM.

The Role of Glucagon in the Pathophysiology and Treatment of Type 2 Diabetes

Type 2 diabetes is a disease involving both inadequate insulin levels and increased glucagon levels. While glucagon and insulin work together to achieve optimal plasma glucose concentrations in healthy individuals, the usual regulatory balance between these 2 critical pancreatic hormones is awry in patients with diabetes. Although clinical discussion often focuses on the role of insulin, glucagon is equally important in understanding type 2 diabetes. Furthermore, an awareness of the role of glucagon is essential to appreciate differences in the mechanisms of action of various classes of glucose-lowering therapies. Newer drug classes such as dipeptidyl peptidase-4 inhibitors and glucagon-like peptide-1 receptor agonists improve glycemic control, in part, by affecting glucagon levels. This review provides an overview of the effect of glucose-lowering therapies on glucagon on the basis of an extensive PubMed literature search to identify clinical studies of glucose-lowering therapies in type 2 diabetes that included assessment of glucagon. Clinical practice currently benefits from available therapies that impact the glucagon regulatory pathway. As clinicians look to the future, improved treatment strategies are likely to emerge that will either use currently available therapies whose mechanisms of action complement each other or take advantage of new therapies based on an improved understanding of glucagon pathophysiology.

Current Therapies That Modify Glucagon Secretion: What Is the Therapeutic Effect of Such Modifications?

PURPOSE OF REVIEW

Hyperglucagonemia contributes significantly to hyperglycemia in type 2 diabetes and suppressed glucagon levels may increase the risk of hypoglycemia. Here, we give a brief overview of glucagon physiology and the role of glucagon in the pathophysiology of type 2 diabetes and provide insights into how antidiabetic drugs influence glucagon secretion as well as a perspective on the future of glucagon-targeting drugs.

RECENT FINDINGS

Several older as well as recent investigations have evaluated the effect of antidiabetic agents on glucagon secretion to understand how glucagon may be involved in the drugs' efficacy and safety profiles. Based on these findings, modulation of glucagon secretion seems to play a hitherto underestimated role in the efficacy and safety of several glucose-lowering drugs. Numerous drugs currently available to diabetologists are capable of altering glucagon secretion: metformin, sulfonylurea compounds, insulin, glucagon-like peptide-1 receptor agonists, dipeptidyl peptidase-4 inhibitors, sodium-glucose cotransporter 2 inhibitors and amylin mimetics. Their diverse effects on glucagon secretion are of importance for their individual efficacy and safety profiles. Understanding how these drugs interact with glucagon secretion may help to optimize treatment.

Effects of DPP-4 inhibitor linagliptin and GLP-1 receptor agonist liraglutide on physiological response to hypoglycaemia in Japanese subjects with type 2 diabetes: A randomized, open-label, 2-arm parallel comparative, exploratory trial

Dipeptidyl peptidase-4 (DPP-4) inhibitors reduce the risk of hypoglycaemia, possibly through augmentation of glucose-dependent insulinotropic polypeptide (GIP) action, but not that of glucagon-like peptide-1 (GLP-1) on glucagon secretion. To examine this model in Japanese individuals with type 2 diabetes (T2D), the effects of the DPP-4 inhibitor linagliptin on glucagon and other counter-regulatory hormone responses to hypoglycaemia were evaluated and compared with those of the GLP-1 receptor agonist liraglutide in a multi-centre, randomized, open-label, 2-arm parallel comparative, exploratory trial. Three-step hypoglycaemic clamp glucose tests preceded by meal tolerance tests were performed before and after 2-week treatment with the drugs. Glucagon levels were increased during the hypoglycaemic clamp test at 2.5 mmol/L. This increase was similar in the linagliptin and liraglutide groups, both before and after the 2-week treatment. Changes in other counter-regulatory hormones (ie, growth hormone, cortisol, epinephrine and norepinephrine) were also similar between the groups, but were suppressed substantially after 2-week treatment compared to baseline. In conclusion, we confirmed that the glucagon response to hypoglycaemia was not affected by linagliptin or liraglutide treatment in Japanese individuals with T2D.

Long-term efficacy and safety of vildagliptin add-on therapy in type 2 diabetes mellitus with insulin treatment

BACKGROUND

The use of dipeptidyl peptidase (DPP)-4 inhibitors in patients with type 2 diabetes treated with insulin may be beneficial. However, the long-term efficacy and safety of vildagliptin add-on therapy in these patients remains unclear.

SUBJECTS AND METHODS

A total of 73 patients with type 2 diabetes treated with insulin were randomly assigned to receive either add-on therapy of vildagliptin (n=37) or conventional therapy without DPP-4 inhibitors (n=36) for glucose control. Hemoglobin A1c (HbA1c) levels, dose and number of insulin injections, number of hypoglycemia episodes, and liver and renal function were monitored for 2years.

RESULTS

The baseline characteristics of subjects, including age, dose of insulin injections, or HbA1c levels, did not differ between the two groups. In the vildagliptin group, HbA1c levels significantly decreased and the significance of HbA1c reduction was maintained for 24months (from 8.0±1.2% to 7.4±1.0%, p<0.05, at the end of observational period). In addition, the dose and number of insulin injections significantly reduced (-5.6units, p<0.01, and -0.9 times, p<0.001). However, these parameters were unchanged in the control group. The number of patients who experienced three or more episodes of hypoglycemia per year was significantly lower in the vildagliptin group (n=4) than in the control group (n=11) (odds ratio, 0.28; 95% confidence interval, 0.08-0.97; p<0.05).

CONCLUSION

Vildagliptin as an add-on to insulin treatment for 24months was well tolerated and led to sustained reductions in HbA1c, the dose and number of insulin injections, and the risk of hypoglycemia.

Comparison between SGLT2 inhibitors and DPP4 inhibitors added to insulin therapy in type 2 diabetes: a systematic review with indirect comparison meta-analysis

BACKGROUND

Both sodium glucose cotransporter 2 (SGLT2) inhibitors and dipeptidyl peptidase-4 (DPP4) inhibitors can be used to treat patients with type 2 diabetes mellitus (T2DM) that is inadequately controlled with insulin therapy, and yet there has been no direct comparison of these two inhibitors.

METHODS

We searched MEDLINE, EMBASE, LILACS, the Cochrane Central Register of Controlled Trials and ClinicalTrials.gov through June 2015. Randomized controlled trials published in English that compare SGLT2 inhibitor plus insulin (SGLT2i/INS) with placebo plus insulin or DPP4 inhibitor plus insulin (DPP4i/INS) with placebo plus insulin in patients with T2DM were selected. Data on the study characteristics, efficacy and safety outcomes were extracted. We compared the efficacy and safety between SGLT2i/INS and DPP4i/INS indirectly with covariates adjustment. Risk of potential bias was assessed.

RESULTS

Fourteen eligible randomized controlled trials comprising 6980 patients were included (five SGLT2 inhibitor studies and nine DPP4 inhibitor studies). Covariate-adjusted indirect comparison using meta-regression analyses revealed that SGLT2i/INS achieved greater reduction in HbA_1c [weighted mean difference (WMD) -0.24%, 95% confidence interval (CI) -0.43 to -0.05%], fasting plasma glucose (WMD -18.0 mg/dL, 95% CI -28.5 to -7.6 mg/dL) and body weight (WMD -2.38 kg, 95% CI -3.18 to -1.58 kg) from baseline than DPP4i/INS without increasing the risk of hypoglycaemia (relative risks 1.19, 95% CI 0.78 to 1.82).

CONCLUSIONS

Sodium glucose cotransporter 2 inhibitors achieved better glycaemic control and greater weight reduction than DPP4 inhibitors without increasing the risk of hypoglycaemia in patients with T2DM that is inadequately controlled with insulin. There has been no direct comparison of SGLT2 inhibitors and DPP4 inhibitors in patients with T2DM inadequately controlled with insulin therapy. In this study, we performed indirect meta-analysis comparing SGLT2 inhibitors and DPP4 inhibitors added to insulin therapy. Without increasing hypoglycaemia, SGLT2 inhibitors showed better glycaemic control and greater weight reduction than DPP4 inhibitors in patients with T2DM inadequately controlled with insulin. The results of the current study could serve as the best available evidence in selecting oral agents to improve glycaemic control in insulin-treated T2DM patients. Copyright © 2016 John Wiley & Sons, Ltd.

Preventive effect of ipragliflozin on nocturnal hypoglycemia in patients with type 2 diabetes treated with basal-bolus insulin therapy: An open-label, single-center, parallel, randomized control study

The efficacy of the administration of sodium-glucose co-transporter 2 inhibitor or the co-administration of sodium-glucose co-transporter 2 inhibitor and dipeptidyl peptidase-4 inhibitor to insulin therapy is not well known. A total of 58 patients with type 2 diabetes, admitted for glycemic control, were randomized to basal-bolus insulin therapy (BBT) alone or BBT plus 50 mg ipragliflozin and/or 20 mg teneligliptin. Insulin doses were adjusted to maintain normal blood glucose levels. Plasma glucose profiles were estimated by continuous glucose monitoring before discharge. Required insulin doses were not significantly different among the treatment groups. The frequency of nocturnal hypoglycemia was significantly lower in the groups treated with ipragliflozin (6.5 ± 10.6%) and ipragliflozin plus teneligliptin (6.9 ± 14.3%) than in the group treated with BBT alone (42 ± 43.6%). The administration of sodium-glucose co-transporter 2 inhibitor with or without dipeptidyl peptidase-4 inhibitor prevented nocturnal hypoglycemia in type 2 diabetes patients with BBT.

Physiological aspects of the combination of insulin and GLP-1 in the regulation of blood glucose control

Combining insulin with glucagon-like peptide-1 (GLP-1) receptor agonists or dipeptidyl peptidase-4 (DPP-4) inhibitors as glucose-lowering therapy for type 2 diabetes is a promising strategy that has gained considerable interest over the past few years. One advantage of this combination is the complementary mechanistic actions of insulin and GLP-1. Insulin increases glucose utilization and retards hepatic glucose production through direct actions in muscle, adipose tissue and the liver. On the other hand, GLP-1 stimulates insulin secretion, inhibits glucagon secretion and retards gastric emptying. Combining these effects results in powerful reductions in both fasting and postprandial glucose through diminished glucose entry into the bloodstream after food consumption, reduced hepatic production of glucose and increased glucose utilization. In addition, GLP-1 receptor agonists induce satiety, leading to decreases in food intakes and body weight, thereby preventing the weight gain often seen with insulin therapy. Clinical trials have verified that these physiological effects as a result of combining insulin with GLP-1 receptor agonists or DPP-4 inhibitors can indeed result in improved glycaemia, with limited risks of hypoglycaemia and weight gain.

Alogliptin for the treatment of type 2 diabetes: a drug safety evaluation

INTRODUCTION

Dipeptidyl peptidase-4 (DPP-4) inhibitors such as alogliptin are becoming more widely established as treatment options for patients with type 2 diabetes (T2DM) because of their ability to improve glycemic control without increasing the risk of hypoglycemia or weight gain. New therapies with improved safety profiles are needed, especially because of the chronic and progressive nature of T2DM.

AREAS COVERED

In this article, the overall safety and tolerability of alogliptin are evaluated based upon a review of the literature. In particular, adverse events (AEs) that have been of interest for the DPP-4 class of drugs, such as the risk of major cardiovascular (CV) events and acute pancreatitis, will be investigated in detail.

EXPERT OPINION

Alogliptin is generally well-tolerated in a broad range of patient populations including different ethnic groups and the elderly. In the pivotal EXAMINE clinical trial, alogliptin was found not to be associated with an increased risk of major CV events or acute pancreatitis/pancreatic cancer.

Effect of Vildagliptin Versus Sulfonylurea in Muslim Patients with Type 2 Diabetes Fasting During Ramadan in Egypt: Results from VIRTUE Study

INTRODUCTION

Fasting in patients with type 2 diabetes mellitus (T2DM) is associated with high risk of hypoglycemia. The aim of this study was to compare the effectiveness and safety of vildagliptin in T2DM patients fasting during Ramadan in a real-life setting in Egypt.

METHODS

In this 16-week prospective and noninterventional study, data were collected up to 6 weeks before and after Ramadan fasting. Patients who had received vildagliptin or sulfonylurea (SU) either as dual therapy with metformin or as monotherapy were enrolled into the study.

RESULTS

Two hundred fifty four patients were enrolled in the study, out of which 246 [121 (97.6%) treated with vildagliptin and 125 (99.2%) with SU] were included in the safety analysis set. A significantly lower proportion of patients experienced ≥1 hypoglycemic event (HE) with vildagliptin as compared to those receiving SUs (1.7% vs. 19.2%, respectively; p < 0.001). No patient in either group reported a grade 2 HE. At week 16, mean change in HbA1c from baseline for vildagliptin and SU were -0.1% and +0.3%, respectively, with a between-treatment difference of -0.4% (p < 0.001). Mean change in body weight from baseline for vildagliptin and SU were -0.8 and -0.1 kg, with a between-treatment difference of -0.7 kg (p = 0.011). A higher proportion of SU-treated patients experienced adverse events compared to those treated with vildagliptin (23.2% vs. 5.8%, respectively), the primary reason being the high incidence of hypoglycemia in the SU group (n = 24, 19.2%).

CONCLUSIONS

Treatment with vildagliptin was associated with lower incidence of hypoglycemia compared with SU and showed good glycemic and weight control in patients with T2DM fasting during Ramadan in a real-life setting in Egypt.

FUNDING

Novartis Pharma AG.

Efficacy and safety of linagliptin as add-on therapy to basal insulin and metformin in people with Type 2 diabetes

AIM

To evaluate the efficacy and safety of linagliptin in people with Type 2 diabetes inadequately controlled on basal insulin and metformin.

METHODS

This was a post hoc subanalysis of participants who received basal insulin and metformin in a global phase III study that randomized participants (1:1) to receive linagliptin 5 mg once daily or placebo for ≥52 weeks as add-on therapy to basal insulin alone or in combination with metformin and/or pioglitazone. During the first 24 weeks, the background dose of basal insulin remained stable; thereafter, adjustments based on glucose concentrations were recommended. The primary endpoint of the subanalysis was the change from baseline in HbA1c after 24 weeks. The safety analysis incorporated data up to a maximum of 110 weeks.

RESULTS

A total of 950 participants receiving background insulin and metformin were included in this subanalysis (linagliptin and placebo, both n = 475). At week 24, the placebo-corrected adjusted mean (±se) change from baseline in HbA1c with linagliptin was -7 (±1) mmol/mol [-0.7 (±0.1) %; 95% CI -0.8, -0.6; P < 0.0001]. The overall frequency of drug-related adverse events (linagliptin, 18.9%; placebo, 21.9%) and investigator-reported hypoglycaemia (linagliptin, 30.7%; placebo, 31.6%) were similar in both groups at the end of treatment. The frequency of severe hypoglycaemia was low (linagliptin, 1.7%; placebo, 0.8%). No meaningful changes in mean (±sd) body weight were noted in either group [week 52: linagliptin, -0.5 (±3.2) kg; placebo, 0.0 (±3.1) kg].

CONCLUSIONS

Linagliptin added to basal insulin and metformin improved glycaemic control, without increasing the risk of hypoglycaemia or body weight gain.

Efficacy and safety of the addition of a dipeptidyl peptidase-4 inhibitor to insulin therapy in patients with type 2 diabetes: A systematic review and meta-analysis

AIMS

To compare the efficacy and safety of the addition of a dipeptidyl peptidase-4 (DPP-4) inhibitor or a placebo in patients with type 2 diabetes inadequately controlled with insulin.

METHODS

We searched randomised controlled trials (RCTs) from MEDLINE, EMBASE, LILACS, the Cochrane Central Register of Controlled Trials and the ClinicalTrials.gov online registry. Studies of at least 12week treatment duration were eligible if they were RCTs in patients with type 2 diabetes comparing addition of a DPP-4 inhibitor to insulin therapy (INS/DPP4i) with addition of a placebo to insulin therapy (INS/PCB) and contained information on the change in glycated haemoglobin (HbA1c) from baseline.

RESULTS

Of 3105 potentially relevant published articles and 206 registered trials, 9 studies were included for meta-analysis. Compared to INS/PCB, INS/DPP4i exhibited a greater reduction in HbA1c (weighted mean difference [WMD] -0.58%; 95% CI -0.70, -0.46) and fasting plasma glucose (WMD -0.59mmol/L; 95% CI -0.79, -0.40) with less daily insulin doses (WMD -1.86IU; 95% CI -3.27, -0.45) and with no difference in weight gain (WMD -0.04kg; 95% CI -0.25, 0.16). The risk of hypoglycaemia was similar between INS/DPP-4i and INS/PCB (the RR in favour of INS/PCB was 0.94; 95% CI 0.84, 1.05).

CONCLUSIONS

Compared to placebo, DPP-4 inhibitors exhibit a better glycaemic control without further increasing the risk of weight gain and hypoglycaemia in patients with type 2 diabetes inadequately controlled with insulin.

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.

Incretin-based drugs for type 2 diabetes: Focus on East Asian perspectives

Type 2 diabetes in East Asians is characterized primarily by β‐cell dysfunction, and with less adiposity and less insulin resistance compared with that in Caucasians. Such pathophysiological differences can determine the appropriate therapeutics for the disease. Incretins, glucose‐dependent insulinotropic polypeptide and glucagon‐like peptide‐1, are secreted in response to meal ingestion, and enhance insulin secretion glucose‐dependently. Incretin‐based drugs, dipeptidyl peptidase‐4 inhibitors (DPP‐4i) and glucagon‐like peptide‐1 receptor agonists, that ameliorate β‐cell dysfunction with limited hypoglycemia risk are now widely used in type 2 diabetes management. Recent meta‐analyses of clinical trials on DPP‐4i and glucagon‐like peptide‐1 receptor agonists found that the drugs were more effective in Asians, most likely because of amelioration of β‐cell dysfunction. In addition, we found increased glycated hemoglobin‐lowering effects of DPP‐4i to be associated with intake of fish in type 2 diabetes, which suggests that dietary customs of East Asians might also underlie the greater efficacy of DPP‐4i. Despite the limited risk, cases of severe hypoglycemia were reported for DPP‐4i/sulfonylureas combinations. Importantly, hypoglycemia was more frequent in patients also receiving glibenclamide or glimepiride, which activate exchange protein directly activated by cyclic adenosine monophosphate 2, a critical mediator of incretin signaling, and was less frequent in patients receiving gliclazide, which does not activate exchange protein directly activated by cyclic adenosine monophosphate 2. Prevention of insulin‐associated hypoglycemia by DPP‐4i has gained attention with regard to the enhancement of hypoglycemia‐induced glucagon secretion by insulinotropic polypeptide, but remains to be investigated in East Asians. Despite the safety issues, which are paramount and must be carefully monitored, the incretin‐based drugs could have potential as a first choice therapy in East Asian type 2 diabetes patients.

DPP-4 inhibitors and cardiovascular disease in type 2 diabetes mellitus. Expectations, observations and perspectives

AIMS

Cardiovascular disease (CVD) is the greatest burden of type 2 diabetes mellitus (T2DM) in terms of morbility, mortality and costs for individuals and societies. Therefore, its prevention is a major goal in diabetes care. Optimal treatment of hyperglycemia is certainly instrumental to CVD prevention. Optimal treatment means both establishing the most appropriate glycemic target for the given individual and selecting the medication(s) with the most favourable benefit/safety ratio. CVD safety, if not a clear CVD benefit, is certainly required for all antidiabetic agents. Dipeptidyl-peptidase-4 (DPP-4) inhibitors are among the classes of antidiabetic agents most recently made available for diabetes care. A major question to be addressed is the effect of these compounds on CVD. Expectations were high for their mechanism of action, which targets also post-prandial glucose and minimize hypoglycemia risk, thereby providing a sort of global glucose control, and for some potentially beneficial extra-glycemic effects. This article reviews the existing literature on this issue.

DATA SYNTHESIS

Data published so far document that DPP-4 inhibitors have a wide spectrum of glycemic and extra-glycemic effects potentially reducing the risk of CVD as well as favourable effects on intermediate or surrogate CVD endpoints. These data heralded a better CVD outcome. Accordingly, pooling CVD safety data from phase 3 and 4 studies conducted with DPP-4 inhibitors suggested that their use might translate into a better CVD outcome. Data from three CVD outcome RCTs with alogliptin, saxagliptin and sitagliptin documented no harm but did not show any benefit on major CVD events. A modest but significant increased risk of hospitalization for heart failure was observed with saxagliptin and with alogliptin (only in subjects with no history of heart failure before randomization) but not with sitagliptin. A study currently in progress with linagliptin will provide further insights in the issue of CVD safety and benefit.

CONCLUSIONS

It should be considered that most alternative oral antidiabetic agents generally do not possess a better CVD risk profile than DPP-4 inhibitors and that some of them, indeed, should be used with caution because of potentially adverse effects on heart and vasculature. Overall, the selection of antidiabetic agent(s) with the most favourable CVD profile is mandatory but still challenging in diabetes care.

Comparative review of dipeptidyl peptidase-4 inhibitors and sulphonylureas

Type 2 diabetes (T2DM) is a progressive disease, and pharmacotherapy with a single agent does not generally provide durable glycaemic control over the long term. Sulphonylurea (SU) drugs have a history stretching back over 60 years, and have traditionally been the mainstay choice as second-line agents to be added to metformin once glycaemic control with metformin monotherapy deteriorates; however, they are associated with undesirable side effects, including increased hypoglycaemia risk and weight gain. Dipeptidyl peptidase (DPP)-4 inhibitors are, by comparison, more recent, with the first compound being launched in 2006, but the class now globally encompasses at least 11 different compounds. DPP-4 inhibitors improve glycaemic control with similar efficacy to SUs, but do not usually provoke hypoglycaemia or weight gain, are relatively free from adverse side effects, and have recently been shown not to increase cardiovascular risk in large prospective safety trials. Because of these factors, DPP-4 inhibitors have become an established therapy for T2DM and are increasingly being positioned earlier in treatment algorithms. The present article reviews these two classes of oral antidiabetic drugs (DPP-4 inhibitors and SUs), highlighting differences and similarities between members of the same class, as well as discussing the potential advantages and disadvantages of the two drug classes. While both classes have their merits, the choice of which to use depends on the characteristics of each individual patient; however, for the majority of patients, DPP-4 inhibitors are now the preferred choice.

Efficacy and Cardiovascular Safety of Linagliptin as an Add-On to Insulin in Type 2 Diabetes: A Pooled Comprehensive Post Hoc Analysis

OBJECTIVE

With the expanding armamentarium of noninsulin therapies for type 2 diabetes mellitus, the use of insulin with various oral agents is becoming more common. In this study, we assessed the efficacy and cardiovascular (CV) safety of the dipeptidyl peptidase-4 inhibitor linagliptin as add-on to insulin in patients with type 2 diabetes.

METHODS

In this post hoc analysis, data for patients receiving basal or basal-bolus insulin were pooled from 4 randomized, double-blind, phase 3 clinical trials of linagliptin 5 mg once daily or placebo given as add-on to background glucose-lowering treatment. Changes in glycated hemoglobin (A1C) and CV risk factors were assessed from baseline to end of trial. The primary CV endpoint was a composite of CV death, nonfatal myocardial infarction, nonfatal stroke and hospitalization due to unstable angina.

RESULTS

The number of patients receiving basal or basal-bolus insulin as background therapy was 1613 (linagliptin: n=811; placebo: n=802). The placebo-adjusted mean (SE) change from baseline in A1C was -0.41 (0.05)% (95% CI -0.50, -0.32; p<0.0001). Treatment with linagliptin provided a relative weight benefit and reduced insulin requirements without affecting blood pressure, heart rate or lipids. The incidence of hypoglycemia with linagliptin was similar to that for placebo (38.7% vs. 39.4%, respectively). The hazard ratio (HR) for the primary endpoint showed that treatment with linagliptin was not associated with an increased CV risk (HR 1.07 [95% CI 0.62, 1.85]).

CONCLUSIONS

Linagliptin, when added to ongoing insulin treatment in patients with type 2 diabetes, improves glycemic control and has a neutral impact on major adverse CV events.

Analyzing the Factors Contributing to Withdrawal from Insulin Therapy Following Additional Administration of Alogliptin: Retrospective Study after Removing Glucotoxicity with Insulin

We attempted to examine whether withdrawal from insulin therapy is or is not possible with administration of additional alogliptin and identify the contributing factors. The subjects were 43 adult patients with type 2 diabetes undergoing insulin therapy after admission. After glucotoxicity was removed, 25 mg alogliptin was additionally administered. Insulin was reduced by 15.6 ± 13.0 units (mean ± SD), and 17 patients (39.5%) completely withdrew from insulin therapy. Several factors were compared between the two groups of patients: those who could withdraw from insulin therapy and those who could not. The former group showed lower HbA1c levels on admission, a lower insulin dose before adding alogliptin, lower injection frequencies, and longer treatment histories prior to admission. Logistic regression analysis showed that lower insulin dose contributed significantly to withdrawal. These results suggest that a lower insulin dose is the best predictor for withdrawal from insulin therapy after adding alogliptin.

Improved glucose control with reduced hypoglycaemic risk when linagliptin is added to basal insulin in elderly patients with type 2 diabetes

AIM

To assess the efficacy, hypoglycaemia risk and other safety markers of linagliptin as an additional therapy in older patients (aged ≥70 years) inadequately controlled with basal insulin.

METHODS

A prespecified safety analysis from the linagliptin trials programme was carried out to explore the hypoglycaemia risk when linagliptin was added to background basal insulin therapy in elderly patients (≥70 years). To do this, two eligible, randomized, placebo-controlled, clinical trials (NCT00954447 and NCT01084005) of 24 and ≥52 weeks, respectively, were analysed.

RESULTS

A total of 247 elderly individuals [mean ± standard deviation (s.d.) age 74 ± 4 years, glycated haemoglobin (HbA1c) 8.2 ± 0.8%] on basal insulin (mean ± s.d. baseline dose 36 ± 25 IU/day) were identified. Alongside placebo-adjusted change in HbA1c with linagliptin of -0.77% [95% confidence interval (CI) -0.95 to 0.59; p < 0.0001] after 24 weeks, the hazard ratios (HRs) of both overall and confirmed hypoglycaemia [blood glucose ≤3.9 mmol/l (70 mg/dl)], were significantly lower with linagliptin than with placebo: HR 0.61 (95% CI 0.39-0.97) versus 0.59 (95% CI 0.37-0.94), respectively (both p < 0.05). Moreover, significantly less confirmed hypoglycaemia was present in linagliptin-treated patients with renal impairment [HR 0.45 (95% CI 0.27-0.76)], moderate hyperglycaemia [HbA1c 7.5 to <9.0%; HR 0.51 (95% CI 0.27-0.99)], lower fasting plasma glucose levels [<152 mg/dl; HR 0.49 (95% CI 0.28-0.86)] and those treated with higher insulin doses [insulin ≥35.6 IU/day; HR 0.46 (95% CI 0.23-0.91); p < 0.05 for all]. Severe hypoglycaemia was rare and the incidence was lower with linagliptin (0.8%) versus placebo (2.5%): HR 0.21 (95% CI 0.02-2.30).

CONCLUSIONS

Despite improvements in hyperglycaemia and no relevant on-trial insulin dose reductions, adding linagliptin to basal insulin appears to decrease hypoglycaemia risk. The biological basis of this phenomenon warrants further research but may involve counter-regulatory effects of incretin hormones.