Glucagon-like peptide analogues for type 2 diabetes mellitus: systematic review and meta-analysis

Impact of Sex and Gender on Clinical Management of Patients with Advanced Chronic Liver Disease and Type 2 Diabetes

Gender differences in the epidemiology, pathophysiological mechanisms and clinical features in chronic liver diseases that may be associated with type 2 diabetes (T2D) have been increasingly reported in recent years. This sexual dimorphism is due to a complex interaction between sex- and gender-related factors, including biological, hormonal, psychological and socio-cultural variables. However, the impact of sex and gender on the management of T2D subjects with liver disease is still unclear. In this regard, sex-related differences deserve careful consideration in pharmacology, aimed at improving drug safety and optimising medical therapy, both in men and women with T2D; moreover, low adherence to and persistence of long-term drug treatment is more common among women. A better understanding of sex- and gender-related differences in this field would provide an opportunity for a tailored diagnostic and therapeutic approach to the management of T2D subjects with chronic liver disease. In this narrative review, we summarized available data on sex- and gender-related differences in chronic liver disease, including metabolic, autoimmune, alcoholic and virus-related forms and their potential evolution towards cirrhosis and/or hepatocarcinoma in T2D subjects, to support their appropriate and personalized clinical management.

Development of a Primary Human Intestinal Epithelium Enriched in L-Cells for Assay of GLP-1 Secretion

Type 2 diabetes mellitus is a chronic disease associated with obesity and dysregulated human feeding behavior. The hormone glucagon-like peptide 1 (GLP-1), a critical regulator of body weight, food intake, and blood glucose levels, is secreted by enteroendocrine L-cells. The paucity of L-cells in primary intestinal cell cultures including organoids and monolayers has made assays of GLP-1 secretion from primary human cells challenging. In the current paper, an analytical assay pipeline consisting of an optimized human intestinal tissue construct enriched in L-cells paired with standard antibody-based GLP-1 assays was developed to screen compounds for the development of pharmaceuticals to modulate L-cell signaling. The addition of the serotonin receptor agonist Bimu 8, optimization of R-spondin and Noggin concentrations, and utilization of vasoactive intestinal peptide (VIP) increased the density of L-cells in a primary human colonic epithelial monolayer. Additionally, the incorporation of an air-liquid interface culture format increased the L-cell number so that the signal-to-noise ratio of conventional enzyme-linked immunoassays could be used to monitor GLP-1 secretion in compound screens. To demonstrate the utility of the optimized analytical method, 21 types of beverage sweeteners were screened for their ability to stimulate GLP-1 secretion. Stevioside and cyclamate were found to be the most potent inducers of GLP-1 secretion. This platform enables the quantification of GLP-1 secretion from human primary L-cells and will have broad application in understanding L-cell formation and physiology and will improve the identification of modulators of human feeding behavior.

Using polyphenols as a relevant therapy to diabetes and its complications, a review

Diabetes is currently a worldwide health concern. Hyperglycemia, hypertension, obesity, and oxidative stress are the major risk factors that inevitably lead to all the complications from diabetes. These complications severely impact the quality of life of patients, and they can be managed, reduced, or even reverted by several polyphenols, plant extracts and foods rich in these compounds. The goal of this review is to approach diabetes not as a single condition but rather an interconnected combination of risk factors and complications. This work shows that polyphenols have multi target action and effects and they have been systematically proven to be relevant in the reduction of each risk factor and improvement of associated complication.

Clinical Considerations When Initiating and Titrating Insulin Degludec/Liraglutide (IDegLira) in People with Type 2 Diabetes

Therapeutic inertia is a substantial obstacle to the initiation of insulin therapy in people with uncontrolled type 2 diabetes (T2D). This effect has in part been perpetuated by concerns over the impact of a burdensome regimen and the increased risk of hypoglycemia and body weight gain often associated with insulin use. An effective, yet simple, less burdensome regimen with a lower risk of body weight gain and hypoglycemia compared with an insulin-only regimen, may help to address these concerns more effectively. We review the available clinical and real-world data on IDegLira, a once-daily, injectable, fixed-ratio combination of insulin degludec (degludec) and the glucagon-like peptide-1 receptor agonist (GLP-1RA) liraglutide, in people with T2D. Evidence from the comprehensive DUAL clinical trial program suggests an advantage of IDegLira over traditional insulin therapies in a number of clinical outcomes, including maintenance of glycemic control, achievement of glycemic targets, reducing the risk of hypoglycemia, and body weight loss. These findings were demonstrated in participants with T2D irrespective of prior GLP-1RA and insulin use. Furthermore, the individual components of IDegLira have confirmed safety (degludec) or significant benefit in terms of improvement of cardiovascular risk (liraglutide). As an injectable therapy that is simple to titrate, IDegLira has the potential to optimize the ability to achieve relevant glycemic targets, and offers a suitable treatment option for people with T2D requiring insulin therapy who are at risk of hypoglycemia or weight gain.

Does evidence matter? Comparative effectiveness research and prescribing of Type 2 diabetes mellitus drugs

Aim: Comparative effectiveness research (CER) can help ascertain value of new drugs; however, limited research assesses the translation of CER into clinical practice. The objective of this study was to analyze the association between CER evidence and prescribing trends within two markets of Type 2 diabetes mellitus. Methods: A retrospective analysis to determine the prescribing trends from 2006 to 2016 and an electronic literature search to identify CER comparing different drugs was conducted. Results: In glucagon-like peptide-1 (GLP-1) agonists market, CER showed superiority of Liraglutide. Prescribing of Exenatide twice daily dropped by 50% points as Liraglutide entered the market. In dipeptidyl peptidase-4 (DPP4) inhibitors market, CER did not suggest conclusive superiority. Nevertheless, Sitagliptin, the first entrant, continued to dominate throughout. Conclusion: CER evidence appeared to be associated with prescribing trends in GLP-1 agonists market; however, no associations were found in DPP4 inhibitors market. The translation of evidence into practice can be limited by the availability of superiority trials and timing of their availability.

Gut hormone polyagonists for the treatment of type 2 diabetes

Chemical derivatives of the gut-derived peptide hormone glucagon-like peptide 1 (GLP-1) are among the best-in-class pharmacotherapies to treat obesity and type 2 diabetes. However, GLP-1 analogs have modest weight lowering capacity, in the range of 5-10%, and the therapeutic window is hampered by dose-dependent side effects. Over the last few years, a new concept has emerged: combining the beneficial effects of several key metabolic hormones into a single molecular entity. Several unimolecular GLP-1-based polyagonists have shown superior metabolic action compared to GLP-1 monotherapies. In this review article, we highlight the history of polyagonists targeting the receptors for GLP-1, GIP and glucagon, and discuss recent progress in expanding of this concept to now allow targeted delivery of nuclear hormones via GLP-1 and other gut hormones, as a novel approach towards more personalized pharmacotherapies.

Exenatide treatment causes suppression of serum fasting ghrelin levels in patients with type 2 diabetes mellitus

AIM

In the present study, we investigated the long-term effects of exenatide treatment on serum fasting ghrelin levels in patients with type 2 diabetes mellitus.

METHODS

Type 2 diabetic patients, who were using metformin with and without the other antihyperglycemic drugs on a stable dose for at least 3 months, were enrolled in the study. BMI>35 kg/m² and HbA1c>7.0% were the additional inclusion criteria. Oral antihyperglycemic drugs, other than metformin, were stopped, and metformin treatment was continued at 2000 mg per day. Exenatide treatment was initiated at 5 µg per dose subcutaneously (sc) twice daily, and after one month, the dose of exenatide was increased to 10 µg twice daily. Changes in anthropometric variables, glycemic control, lipid parameters and total ghrelin levels were evaluated at baseline and following 12 weeks of treatment.

RESULTS

Thirty-eight patients (male/female = 7/31) entered the study. The mean age of patients was 50.5 ± 8.8 years with a mean diabetes duration of 8.5 ± 4.9 years. The mean BMI was 41.6 ± 6.3 kg/m² and the mean HbA1c of patients was 8.9 ± 1.4%. The mean change in the weight of patients was -5.6 kg and the percentage change in weight was -5.2 ± 3.7% following 12 weeks of treatment. BMI, fasting plasma glucose and HbA1c levels of patients were decreased significantly (P < 0.001 and P < 0.001; respectively), while there was no change in lipid parameters. Serum fasting ghrelin levels were significantly suppressed following 12 weeks of exenatide treatment compared with baseline values (328.4 ± 166.8 vs 245.3 ± 164.8 pg/mL) (P = 0.024).

CONCLUSION

These results suggest that the effects of exenatide on weight loss may be related with the suppression of serum fasting ghrelin levels, which is an orexigenic peptide.

THE EFFECT OF EXENATIDE THERAPY IN PREVIOUSLY INSULIN-TREATED TYPE 2 DIABETIC PATIENTS

OBJECTIVE

To evaluate the effect of multiple daily injection (MDI) treatment replaced by Exenatide BID as compared with continuation of MDI.

PATIENTS AND METHODS

A total of 140 patients with type 2 diabetes, taking metformin and multiple daily insulin injections, were randomized to exenatide or insulin group that continued their insulin treatment. Patients were followed-up for 16 weeks. Blood glucose profiles, BMI, waist circumference, HbA1C, serum lipids and side effects were assesssed at weeks 0,12 and 16.

RESULTS

There were no significant differences between the two groups with respect to baseline parameters. Glycemic control was similar between the two groups. The mean changes in HbA1C in exenatide group were -0.66±0.63% and in insulin group -0.74±0.92 % (p=0.594). In exenatide group, 59.6 % of patients and in insulin group 85.71 % of patients had maintained or improved glycemic control at the end of the study. In insulin group, insulin requirement increased 5.86 ± 4.46 units/day. Body weight and waist circumference decreased significantly in exenatide treatment group with respect to insulin group (p<0.001).

CONCLUSIONS

Substituting exenatide for insulin might be an option in insulin-treated, type 2 diabetic patients having obesity, and poor glycemic control. However, patients with longer duration of diabetes and insulin treatment and with lower C-peptide levels might not benefit from exenatide therapy.

Treatment with GLP1 receptor agonists reduce serum CRP concentrations in patients with type 2 diabetes mellitus: A systematic review and meta-analysis of randomized controlled trials

AIM

To undertake a systematic review and meta-analysis of randomized controlled trials of the effect of glucagon-like peptide-1 receptor agonist (GLP-1 RAs) therapy on serum C-reactive protein (CRP) concentrations.

METHOD

PubMed-Medline, SCOPUS, Web of Science and Google Scholar databases were searched for the period up until March 16, 2016. Prospective studies evaluating the impact of GLP-1 RAs on serum CRP were identified. A random effects model (using the DerSimonian-Laird method) and generic inverse variance methods were used for quantitative data synthesis. Sensitivity analysis was conducted using the leave-one-out method. Heterogeneity was quantitatively assessed using the I² index. Random effects meta-regression was performed using unrestricted maximum likelihood method to evaluate the impact of potential moderator. International Prospective Register for Systematic Reviews (PROSPERO) number CRD42016036868.

RESULTS

Meta-analysis of the data from 7 treatment arms revealed a significant reduction in serum CRP concentrations following treatment with GLP-1 RAs (WMD -2.14 (mg/dL), 95% CI -3.51, -0.78, P=0.002; I² 96.1%). Removal of one study in the meta-analysis did not change the result in the sensitivity analysis (WMD -2.14 (mg/dL), 95% CI -3.51, -0.78, P=0.002; I² 96.1%), indicating that our results could not be solely attributed to the effect of a single study. Random effects meta-regression was performed to evaluate the impact of potential moderator on the estimated effect size. Changes in serum CRP concentration were associated with the duration of treatment (slope -0.097, 95% CI -0.158, -0.042, P<0.001).

CONCLUSIONS

This meta-analysis suggests that GLP-1 RAs therapy causes a significant reduction in CRP.

Incretin-Based Therapy and Risk of Pancreatic Cancer in Patients with Type 2 Diabetes Mellitus: A Meta-analysis of Randomized Controlled Trials

INTRODUCTION

The present study aims to evaluate the risk of pancreatic cancer with incretin-based therapy among patients with type 2 diabetes mellitus (T2DM).

METHODS

We searched EMBASE, MEDLINE, the Cochrane Central Register of Controlled Trials and ClinicalTrials.gov for eligible studies published up to March 06 2016. This meta-analysis includes all studies reporting adverse events of pancreatic cancer with use of incretin-based therapies compared with placebo or non-incretin anti-diabetic drugs in patients with T2DM. We used fixed-effect model to compare pooled relative risk (RR) with related 95% confidence intervals (CI).

RESULTS

A total of 159 randomized trials were identified. Out of these, 135 studies were excluded as pancreatic cancer occurrence had not been included as an end point. The remaining 24 trials enrolling 47,904 participants were further assessed. Overall, no increased risk of pancreatic cancer were detected in association with incretin-based treatment (RR = 0.7, 95% CI 0.37-1.05). The incidence of pancreatic neoplasm was even lower among incretin-based groups than controls (RR = 0.50, 95% CI 0.29-0.87) in trials with duration more than 104 weeks. There was even decreased risk of pancreatic cancer within groups paralleled by incretin-matched placebos (RR = 0.55, 95% CI 0.32-0.93) than by non-incretin anti-diabetic drugs. Neither monotherapy (RR = 0.62, 95% CI 0.38-1.01) nor combination regimen (RR = 0.92, 95% CI 0.45-1.90) of incretin mimetics increased the risk of pancreatic cancer.

CONCLUSION

This meta-analysis shows that incretin-based therapies are not associated with increase in the risk of pancreatic cancer. Interestingly, subgroup analyses suggested lower risk of pancreatic cancer in incretin groups than placebo in long-term studies (>104 weeks). Considering the inconsistent results among randomized trials and previous epidemiological investigations, more such studies should be conducted to clarify the existence or non-existence of this association.

FUNDING

This work was supported by grants from the National Natural Science Foundation of China (Nos. 81270476 and 81470830).

Pharmacological Actions of Glucagon-Like Peptide-1, Gastric Inhibitory Polypeptide, and Glucagon

Glucagon family of peptide hormones is a group of structurally related brain-gut peptides that exert their pleiotropic actions through interactions with unique members of class B1 G protein-coupled receptors (GPCRs). They are key regulators of hormonal homeostasis and are important drug targets for metabolic disorders such as type-2 diabetes mellitus (T2DM), obesity, and dysregulations of the nervous systems such as migraine, anxiety, depression, neurodegeneration, psychiatric disorders, and cardiovascular diseases. The current review aims to provide a detailed overview of the current understanding of the pharmacological actions and therapeutic advances of three members within this family including glucagon-like peptide-1 (GLP-1), gastric inhibitory polypeptide (GIP), and glucagon.

Combination therapy of SGLT2 inhibitors with incretin-based therapies for the treatment of type 2 diabetes mellitus: Effects and mechanisms of action

Type 2 diabetes mellitus (T2DM) is a growing health problem worldwide; its pathogenesis is multifactorial and its progressive nature often necessitates a combination therapy with multiple antihyperglycemic agents. Sodium glucose cotransporter 2 (SGLT2) inhibitors and the incretin-based therapies - dipeptidyl peptidase 4(DPP-4) inhibitors and glucagon-like peptide 1 (GLP-1) receptor agonists - were introduced for the treatment of T2DM within the last decade. Evidence of the beneficial effects of these antihyperglycemic agents on micro- and macrovascular complications have started to emerge, which will become important in individualizing different combinations of antihyperglycemic agents to different patient populations. We review here the mechanisms of action, glycemic and cardiovascular effects of SGLT2 inhibitors and incretin-based therapies and their combination in the treatment of T2DM.

Use of incretin agents and risk of pancreatic cancer: a population-based cohort study

AIM

To investigate the association between the use of incretin agents and the risk of pancreatic cancer.

METHODS

A retrospective population-based cohort study, using data from the Clinical Practice Research Datalink, 2007-2012, was conducted. Patients (n = 182 428) with at least one non-insulin antidiabetic drug (NIAD) prescription and aged ≥18 years during data collection, were matched one-to-one to control patients without diabetes. Multivariable Cox proportional hazards models and a new user design were used to estimate the hazard ratio (HR) of pancreatic cancer in incretin users (n = 28 370) compared with control subjects without diabetes and other NIAD-treated patients. Time-dependent adjustments were made for age, sex, lifestyle, comorbidities and drug use.

RESULTS

The mean duration of follow-up was 4.1 years for incretin users. Current NIAD use was associated with a fourfold increased risk of pancreatic cancer [HR 4.28, 95% confidence interval (CI) 3.49-5.24]. This risk was almost doubled among current incretin users as compared with control subjects. Incretin use was not associated with pancreatic cancer when compared with control subjects with diabetes (HR 1.36, 95% CI 0.94-1.96); however, the 'new user' design did show an association between incretin use and pancreatic cancer when compared with control subjects with diabetes. In both cohorts with prevalent and incident users of antidiabetic drugs, the risk of pancreatic cancer almost doubled in those who had recently initiated incretin therapy (up to seven prescriptions), whereas this elevated risk dropped to baseline levels with prolonged use.

CONCLUSIONS

We found that incretin use was not associated with pancreatic cancer after adjustment for the severity of the underlying Type 2 Diabetes Mellitus (T2DM). The elevated risk of pancreatic cancer in those recently initiating incretin agents is likely to be caused by protopathic bias or other types of unknown distortion. The presence of considerable confounding by disease severity and the lack of a duration-of-use relationship do not support a causal explanation for the association between incretin agents and pancreatic cancer.

Glucagon-like peptide-1 agonists combating clozapine-associated obesity and diabetes

Clozapine is the most effective antipsychotic, but its use is tempered by adverse metabolic effects such as weight gain, glucose intolerance and type II diabetes. Current interventions do not facilitate compelling or sustained improvement in metabolic status. Recent studies suggest that glucagon-like peptide-1 (GLP-1) may play a key role in clozapine's metabolic effects, possibly suggesting that clozapine-associated obesity and diabetes are mediated independently through reduced GLP-1. As a result, GLP-1 agonists could show promise in reversing antipsychotic-induced metabolic derangements, providing mechanistic justification that they may represent a novel approach to treat, and ultimately prevent, both diabetes and obesity in patients on clozapine. GLP-1 agonists are already used for diabetes, and they provide a unique combination of glycaemic improvement and metabolically relevant weight loss in diabetic and non-diabetic patients, in the context of a currently favourable safety profile. Using GLP-1 agonists for clozapine-associated obesity and diabetes could be a potentially effective intervention that may reduce cardiometabolic morbidity and mortality in this vulnerable patient population.

Incretin based drugs and the risk of pancreatic cancer: international multicentre cohort study

OBJECTIVE

To determine whether the use of incretin based drugs compared with sulfonylureas is associated with an increased risk of incident pancreatic cancer in people with type 2 diabetes.

DESIGN

Population based cohort.

SETTING

Large, international, multicentre study combining the health records from six participating sites in Canada, the United States, and the United Kingdom.

PARTICIPANTS

A cohort of 972,384 patients initiating antidiabetic drugs between 1 January 2007 and 30 June 2013, with follow-up until 30 June 2014.

MAIN OUTCOME MEASURES

Within each cohort we conducted nested case-control analyses, where incident cases of pancreatic cancer were matched with up to 20 controls on sex, age, cohort entry date, duration of treated diabetes, and duration of follow-up. Hazard ratios and 95% confidence intervals for incident pancreatic cancer were estimated, comparing use of incretin based drugs with use of sulfonylureas, with drug use lagged by one year for latency purposes. Secondary analyses assessed whether the risk varied by class (dipeptidyl peptidase-4 inhibitors and glucagon-like peptide-1 receptor agonists) or by duration of use (cumulative duration of use and time since treatment initiation). Site specific hazard ratios were pooled using random effects models.

RESULTS

During 2,024,441 person years of follow-up (median follow-up ranging from 1.3 to 2.8 years; maximum 8 years), 1221 patients were newly diagnosed as having pancreatic cancer (incidence rate 0.60 per 1000 person years). Compared with sulfonylureas, incretin based drugs were not associated with an increased risk of pancreatic cancer (pooled adjusted hazard ratio 1.02, 95% confidence interval 0.84 to 1.23). Similarly, the risk did not vary by class and evidence of a duration-response relation was lacking.

CONCLUSIONS

In this large, population based study the use of incretin based drugs was not associated with an increased risk of pancreatic cancer compared with sulfonylureas. Although this potential adverse drug reaction will need to be monitored long term owing to the latency of the cancer, these findings provide some reassurance on the safety of incretin based drugs.

Baseline ALT levels as a marker of glycemic response to treatment with GLP-1 receptor agonists

BACKGROUND AND OBJECTIVES

This study aimed to assess if ALT levels, as a marker of non-alcoholic fatty liver disease, may predict HbA1c response to treatment with GLP-1 receptor agonists (GLP-1 RAs).

PATIENTS AND METHODS

A retrospective, longitudinal, analytical study was conducted including patients with type 2 diabetes mellitus continuously treated with GLP-1 agonists (85% with liraglutide) for one year. Patients were divided into two groups according to baseline ALT levels, with 24 U/L (the median of the distribution) as the cut-off point. The dependent variable was HbA1c change (one-year follow-up minus baseline). The predictive value of ALT levels above 24 U/L and ALT change was analyzed using multivariate linear regression adjusted to age, gender, diabetes duration, type and dose of GLP-1 RA, baseline HbA1c, baseline body mass index (BMI), and change in BMI.

RESULTS

A total of 117 patients (48% females) aged 58.6 (SD 9.6) years were enrolled into the study. Treatment was associated with a change in ALT of -4.3 U/L (p=0.041) and a change in HbA1c of -1.1% (p<0.0001). Decreases in HbA1c (-1.41% vs -0.76%; p=0.045) and ALT (-9.25 vs 0.46 U/L; p=0.002) were significantly higher in patients with ALT levels above the median. In the multivariate analysis, both ALT>24 U/L (b=-0.74; 95%CI: -1.31 to -0.18; p=0.011) and ALT change (b=0.028; 95%CI: 0.010 to 0.046; p=0.003), were significant response predictors.

CONCLUSIONS

Elevated baseline transaminase values and decreased transaminase levels during follow-up are associated to a favorable glycemic response to GLP-1 RAs.

Efficacy and safety of dulaglutide in patients with type 2 diabetes: a meta-analysis and systematic review

A meta-analysis was conducted to assess the clinical efficacy and safety of dulaglutide in patients with type 2 diabetes mellitus (T2DM). Medline, Embase, Cochrane Library and www. clinicaltrials. gov (up to February 15^th, 2015) were searched. Randomized controlled trials comparing dulaglutide to other drugs for T2DM were collected. Twelve RCTs were included, and the overall bias was low. As the monotherapy, compared with control (placebo, metformin and liraglutide), dulaglutide resulted in a significant reduction in HbA1c (WMD, −0.68%; 95% CI, −0.95 to −0.40), FPG (WMD, −0.90 mmol/L; 95% CI, −1.28 to −0.52), a similar risk of hypoglycemia (7.8% vs. 10.6%), less body weight loss (WMD, 0.51 kg; 95% CI, 0.27 to 0.75). As an add-on intervention with oral antihyperglycemic medication (OAM) and insulin, compared with control (placebo, sitagliptin, exenatide, liraglutide and glargine), dulaglutide lowered HbA1c (WMD, −0.51%; 95% CI, −0.68 to −0.35) and body weight significantly (WMD, −1.30 kg, 95% CI, −1.85 to −1.02) notably, and elicited a similar reduction in FPG (WMD, −0.19 mmol/L; 95% CI, −1.20 to 0.82), an similar incidence of hypoglycemia (24.5% vs. 24.5%). This meta-analysis revealed the use of dulaglutide as a monotherapy or an add-on to OAM and lispro appeared to be effective and safe for adults with T2DM.

Exenatide Treatment Causes Suppression of Serum Ghrelin Levels following Mixed Meal Test in Obese Diabetic Women

AIM

To investigate the effect of exenatide treatment on serum ghrelin levels in obese female patients with type 2 diabetes mellitus.

METHODS

Fourteen female patients with type 2 diabetes mellitus being treated with metformin and exenatide were enrolled. A mixed meal test was applied to the patients while continuing with their daily medications. Blood samples were taken before and at 60, 120, and 180 minutes following mixed meal test to measure serum total ghrelin, glucose, and insulin levels. The following week, exenatide treatment of the patients was paused for 24 hours and the same experimental procedures were repeated.

RESULTS

Serum ghrelin levels were suppressed significantly at 180 minutes with exenatide treatment compared with baseline (294.4 ± 57.5 versus 234.5 ± 59.4 pg/mL) (p < 0.001). Serum ghrelin levels at 180 minutes were statistically different when percentage change in serum ghrelin levels after mixed meal tests with and without exenatide usage were compared (p = 0.001). Estimated total area under the curve values for serum ghrelin concentrations was also significantly lower with exenatide compared with omitted treatment (p = 0.035).

CONCLUSION

These results suggest that the effect of exenatide on weight loss may be related with the suppression of serum ghrelin levels, which is an orexigenic peptide.

Drug-related risk of severe hypoglycaemia in observational studies: a systematic review and meta-analysis

BACKGROUND

Diabetes mellitus (DM) leads to multiple complications, including severe hypoglycaemia events (SHEs). SHEs can impact a patient's quality of life and compliance and may directly result in additional costs to the health care system. The aim of this review was to evaluate the risk of severe hypoglycaemia in patients with type 1 (T1) and 2 (T2) DM as observed in everyday clinical practice for various drug regimens.

METHODS

We conducted a systematic review of observational (retrospective or prospective) studies in the MEDLINE, Embase, and Cochrane Library databases that covered at least 100 children or adults with T1/T2 DM. In T1 DM, basal-bolus/pre-mix insulin (human or analogue) and insulin pump were reviewed, and in T2 DM, basal-bolus/pre-mix insulin (human or analogue), oral antidiabetic drugs supported with basal insulin (human or analogue), sulfonylureas in monotherapy, and combined oral treatment were reviewed. In order to estimate SHE rates, we extracted data on the time horizon of the study, number of patients, number of SHEs, and number of patients experiencing at least one SHE. We used a random effects model to estimate the annual SHE rate. We considered the risk for other antidiabetic medications in T2 DM to be negligible and the results of our main review yielded no observational data for premixes in T1 DM so they were assessed based on relative rates taken from additional systematic reviews. The study, being a desk research, did not involve any human subjects (including human material or human data) and no ethical committee approval was asked for. For the same reason there was no need to collect informed consent for participation in the study.

RESULTS

We identified 76 observational studies encompassing 707,722.30 patient-years. The estimated annual SHE rate varied from 0.168 (95 % CI 0.123-0.237) for insulin pump up to 1.628 for biphasic human insulin in T1 DM patients, and from 0.0035 for oral antidiabetic drugs up to 0.554 (95 % CI 0.157-7.534) for basal-bolus with human insulin in T2 DM patients.

CONCLUSIONS

Our review indicates that SHE rates differ between patients depending on treatment regimen. However, SHEs are also driven by other factors. Proper modelling techniques are needed to use various types of information in published studies.

Effectiveness and Persistence with Liraglutide Among Patients with Type 2 Diabetes in Routine Clinical Practice--EVIDENCE: A Prospective, 2-Year Follow-Up, Observational, Post-Marketing Study

Introduction

The aim of this study was to investigate whether the efficacy of liraglutide observed in randomized controlled trials translates into therapeutic benefits in the French population during routine clinical practice.

Methods

This observational, prospective, multicenter study included 3152 adults with type 2 diabetes who had recently started or were about to start liraglutide treatment. During 2 years of follow-up, an evaluation of the reasons for prescribing liraglutide, maintenance dose of liraglutide, changes in combined antidiabetic treatments, level of glycemic control, change in body weight and body mass index (BMI), patient satisfaction with diabetes treatment and safety of liraglutide were investigated. The primary study endpoint was the proportion of patients still receiving liraglutide and presenting with HbA_1c <7.0% after 2 years of follow-up.

Results

At the end of the study, 29.5% of patients maintained liraglutide treatment and reached the HbA_1c target. Mean (±SD) HbA_1c, fasting plasma glucose concentration, body weight and BMI were significantly reduced from baseline [8.46% (±1.46) to 7.44% (±1.20); 180 (±60) to 146 (±44) mg/dL; 95.2 (±20.0) to 91.1 (±19.6) kg; 34.0 (±7.2) to 32.5 (±6.9) kg/m²; respectively, all P < 0.0001]. Patient treatment satisfaction increased, with the mean diabetes treatment satisfaction questionnaire status version score increasing from 22.17 (±7.64) to 28.55 (±5.79), P < 0.0001. The main adverse event type was gastrointestinal, with a frequency of 10.9%, and the percentage of patients suffering ≥1 hypoglycemic episode decreased from 6.9% to 4.4%.

Conclusion

The results of the EVIDENCE study suggest that the effectiveness of liraglutide in real-world clinical practice is similar to that observed in randomized controlled trials.

Funding

Novo Nordisk A/S.

Trial Registration

ClinicalTrials.gov identifier, NCT01226966.

Electronic supplementary material

The online version of this article (doi:10.1007/s12325-015-0245-x) contains supplementary material, which is available to authorized users.

A novel, long-acting glucagon-like peptide receptor-agonist: dulaglutide

BACKGROUND

Dulaglutide is a new, long-acting glucagon-like peptide analogue in the treatment of type 2 diabetes. It is available in two doses, 0.75 and 1.5 mg, given by injection once weekly. This systematic review reports the effectiveness and safety of dulaglutide in type 2 diabetes in dual and triple therapy.

METHODS

MEDLINE, MEDLINE In-Process and Other Non-Indexed Citations, EMBASE, and conference abstracts were searched from 2005 to August 2014, and updated in January 2015. Company websites and references of included studies were checked for potentially relevant studies. European Medicines Agency and US Food and Drug Administration websites were searched.

RESULTS

Four trials were included. All were manufacturer-funded randomized controlled trials from the Assessment of Weekly Administration of Dulaglutide in Diabetes (AWARD) program. AWARD-1 compared dulaglutide 1.5 mg against exenatide 10 µg twice daily and placebo, AWARD-2 compared dulaglutide 0.75 and 1.5 mg against insulin glargine, AWARD-5 compared dulaglutide 0.75 and 1.5 mg against sitagliptin 100 mg and placebo, and AWARD-6 compared dulaglutide 1.5 mg against liraglutide 1.8 mg. The duration of follow-up in the trials ranged from 26 to 104 weeks. The primary outcome of all the included trials was change in HbA1c. At 26 weeks, greater HbA1c reductions were seen with dulaglutide than with twice daily exenatide (dulaglutide 1.5/0.75 mg: -1.5%/-1.3%; exe: 0.99%) and sitagliptin (1.5/0.75 mg -1.22%/-1.01%; sitagliptin: -0.6%). HbA1c change was greater with dulaglutide 1.5 mg (-1.08%) than with glargine (-0.63%), but not with dulaglutide 0.75 mg (-0.76%). Dulaglutide 1.5 mg was found to be noninferior to liraglutide 1.8 mg. More patients treated with dulaglutide achieved HbA1c targets of <7% and ≤6.5%. Reduction in weight was greater with dulaglutide than with sitagliptin and exenatide. Hypoglycemia was infrequent. The main adverse events were nausea, diarrhea, and vomiting.

CONCLUSION

Dulaglutide is effective in the treatment of patients with type 2 diabetes but we need long follow-up data for safety concerns.

Evidence That in Uncontrolled Diabetes, Hyperglucagonemia Is Required for Ketosis but Not for Increased Hepatic Glucose Production or Hyperglycemia

Several lines of evidence implicate excess glucagon secretion in the elevated rates of hepatic glucose production (HGP), hyperglycemia, and ketosis characteristic of uncontrolled insulin-deficient diabetes (uDM), but whether hyperglucagonemia is required for hyperglycemia in this setting is unknown. To address this question, adult male Wistar rats received either streptozotocin (STZ) to induce uDM (STZ-DM) or vehicle and remained nondiabetic. Four days later, animals received daily subcutaneous injections of either the synthetic GLP-1 receptor agonist liraglutide in a dose-escalating regimen to reverse hyperglucagonemia or its vehicle for 10 days. As expected, plasma glucagon levels were elevated in STZ-DM rats, and although liraglutide treatment lowered glucagon levels to those of nondiabetic controls, it failed to attenuate diabetic hyperglycemia, elevated rates of glucose appearance (Ra), or increased hepatic gluconeogenic gene expression. In contrast, it markedly reduced levels of both plasma ketone bodies and hepatic expression of the rate-limiting enzyme involved in ketone body production. To independently confirm this finding, in a separate study, treatment of STZ-DM rats with a glucagon-neutralizing antibody was sufficient to potently lower plasma ketone bodies but failed to normalize elevated levels of either blood glucose or Ra. These data suggest that in rats with uDM, hyperglucagonemia is required for ketosis but not for increased HGP or hyperglycemia.

Central obesity, type 2 diabetes and insulin: exploring a pathway full of thorns

The prevalence of type 2 diabetes (T2D) is rapidly increasing. This is strongly related to the contemporary lifestyle changes that have resulted in increased rates of overweight individuals and obesity. Central (intra-abdominal) obesity is observed in the majority of patients with T2D. It is associated with insulin resistance, mainly at the level of skeletal muscle, adipose tissue and liver. The discovery of macrophage infiltration in the abdominal adipose tissue and the unbalanced production of adipocyte cytokines (adipokines) was an essential step towards novel research perspectives for a better understanding of the molecular mechanisms governing the development of insulin resistance. Furthermore, in an obese state, the increased cellular uptake of non-esterified fatty acids is exacerbated without any subsequent β-oxidation. This in turn contributes to the accumulation of intermediate lipid metabolites that cause defects in the insulin signaling pathway. This paper examines the possible cellular mechanisms that connect central obesity with defects in the insulin pathway. It discusses the discrepancies observed from studies organized in cell cultures, animal models and humans. Finally, it emphasizes the need for therapeutic strategies in order to achieve weight reduction in overweight and obese patients with T2D.

Treatment of clozapine-associated obesity and diabetes with exenatide (CODEX) in adults with schizophrenia: study protocol for a pilot randomised controlled trial

BACKGROUND

Clozapine causes significant metabolic disturbances including obesity and type 2 diabetes. Recent evidence that reduced glucagon-like-peptide-1 (GLP-1) may contribute to aetiology of clozapine-associated metabolic dysregulation suggests a potential therapeutic role for GLP-1 agonists.

METHOD

This open-label, pilot randomised controlled trial evaluates the effect of exenatide in clozapine-treated obese adults who have schizophrenia, with or without poorly controlled diabetes. Sixty out-patients will be randomised to once weekly extended release exenatide or treatment as usual for 24 weeks.

AIMS

To evaluate the feasibility of larger studies regarding methodology, acceptability, tolerability and estimate efficacy for glycaemic control or weight loss. Secondary outcomes are psychosis severity and metabolic parameters.

CONCLUSIONS

This is the first trial investigating GLP-1 agonists for glycaemic control and weight loss in clozapine-treated patients with either diabetes or obesity. Clozapine-associated obesity and diabetes with exenatide (CODEX) will provide proof-of-concept empirical evidence addressing whether this novel treatment is practical and worthy of further investigation.

DECLARATION OF INTEREST

A.W.R. has received speaker honoraria and travel grants from AstraZeneca, BoehringerIngelheim, Eli Lilly, MSD, Novo Nordisk and Sanofi and has participated on advisory panels for MSD and Novo Nordisk.

COPYRIGHT AND USAGE

© The Royal College of Psychiatrists 2015. This is an open access article distributed under the terms of the Creative Commons Non-Commercial, No Derivatives (CC BY-NC-ND) licence.

Pilot study of liraglutide effects in non-alcoholic steatohepatitis and non-alcoholic fatty liver disease with glucose intolerance in Japanese patients (LEAN-J)

AIM

Non-alcoholic fatty liver disease (NAFLD), a hepatic manifestation of metabolic syndrome, is associated with an increased risk of developing lifestyle-related diseases including type 2 diabetes, cardiovascular disease and cerebral vessel disease. No current drug therapy provides the ideal effects of decreasing hepatic inflammation while simultaneously improving liver fibrosis. Liraglutide is a glucagon-like peptide-1 receptor agonist that affects the histological findings in patients with non-alcoholic steatohepatitis (NASH). This study was conducted to evaluate the effect and action of liraglutide for biopsy-proven NASH.

METHODS

After lifestyle modification intervention for 24 weeks, subjects whose hemoglobin A1c levels failed to improve to less than 6.0% and/or whose alanine aminotransferase levels were not lower than baseline, received liraglutide at 0.9 mg/body per day for 24 weeks.

RESULTS

Of 27 subjects, 26 completed the lifestyle modification intervention. Nineteen subjects received liraglutide therapy for 24 weeks. Body mass index, visceral fat accumulation, aminotransferases and glucose abnormalities improved significantly. Repeated liver biopsy was performed in 10 subjects who continued liraglutide therapy for 96 weeks. Six subjects showed decreased histological inflammation as determined by NASH activity score and stage determined by Brunt classification. We saw no significant adverse events during therapy with liraglutide.

CONCLUSION

Our pilot study demonstrated that treatment with liraglutide had a good safety profile and significantly improved liver function and histological features in NASH patients with glucose intolerance.

Effects of glucagon-like peptide-1 receptor agonists on weight loss in patients with type 2 diabetes: a systematic review and network meta-analysis

To evaluate the effectiveness of glucagon-like peptide-1 receptor agonists (GLP-1 RAs) on weight reduction in patients with Type 2 diabetes mellitus (Type 2 DM), a network meta-analysis was conducted. MEDLINE, EMBASE, Cochrane Library, and ClinicalTrials.gov were searched from 1950 to October 2013. Randomized controlled trials (RCTs) involving GLP-1 RAs were included if they provided information on body weight. A total of 51 RCTs were included and 17521 participants were enrolled. The mean duration of 51 RCTs was 31 weeks. Exenatide 10 μg twice daily (EX10BID) reduced weight compared with exenatide 5 μg twice daily (EX5BID), liraglutide 0.6 mg once daily (LIR0.6QD), liraglutide-1.2 mg once daily (LIR1.2QD), and placebo treatment, with mean differences of -1.07 kg (95% CI: -2.41, -0.02), -2.38 kg (95% CI: -3.71, -1.06), -1.62 kg (95% CI: -2.79, -0.43), and -1.92 kg (95% CI: -2.61, -1.24), respectively. Reductions of weight treated with liraglutide-1.8 mg once daily (LIR1.8QD) reach statistical significance (-1.43 kg (95% CI: -2.73, -0.15)) versus LIR1.2QD and (-0.98 kg (95% CI: -1.94, -0.02)) versus placebo. Network meta-analysis found that EX10BID, LIR1.8QD, and EX2QW obtained a higher proportion of patients with weight loss than other traditional hypoglycemic agents. Our results suggest GLP-1 RAs are promising candidates for weight control in comparison with traditional hypoglycemic drugs, and EX10BID, LIR1.8QD, and EX2QW rank the top three drugs.

Gastrointestinal adverse events of glucagon-like peptide-1 receptor agonists in patients with type 2 diabetes: a systematic review and network meta-analysis

INTRODUCTION

Glucagon-like peptide-1 receptor agonists (GLP-1 RAs) are a new class of drugs used in the treatment of type 2 diabetes mellitus (T2DM). Gastrointestinal (GI) adverse events (AEs) are the most frequently reported treatment-related AEs for GLP-1 RAs. We aim to evaluate the effect of GLP-1 RAs on the incidence of GI AEs of T2DM.

MATERIALS AND METHODS

The overview of the GI events of GLP-1 RAs has been performed on relevant publications through the literature search, such as MEDLINE, EMBASE, Cochrane Library, and ClinicalTrials.gov The manufacturer was contacted regarding unpublished data. We analyzed direct and indirect comparisons of different treatments using Bayesian network meta-analysis.

RESULTS

Taspoglutide 30 mg once weekly (TAS30QW) and lixisenatide 30 μg twice daily (LIX30BID) were ranked the top two drugs in terms of GI AEs versus placebo. The odds ratios of nausea and vomiting for TAS30QW were 11.8 (95% confidence interval [CI], 2.89, 46.9) and 51.7 (95% CI, 7.07, 415), respectively, and that of diarrhea was 4.93 (95% CI, 1.75, 14.7) for LIX30BID.

CONCLUSIONS

Our study found all GLP-1 RA dose regimens significantly increased the incidence of GI AEs, compared with placebo or conventional treatment. The occurrence of GI AEs was different with diverse dose regimens of GLP-1 RAs. TAS30QW had the maximum probability to occur nausea and vomiting, whereas LIX30BID had the maximum probability to cause development of diarrhea versus other treatments.

Glucagon secretion after metabolic surgery in diabetic rodents

Excessive or inadequate glucagon secretion promoting hepatic gluconeogenesis and glycogenolysis is believed to contribute to hyperglycemia in patients with type 2 diabetes. Currently, metabolic surgery is an accepted treatment for obese patients with type 2 diabetes and has been shown to improve glycemic control in Goto-Kakizaki (GK) rats, a lean animal model for type 2 diabetes. However, the effects of surgery on glucagon secretion are not yet well established. In this study, we randomly assigned forty 12- to 14-week-old GK rats to four groups: control group (GKC), sham surgery (GKSS), sleeve gastrectomy (GKSG), and gastric bypass (GKGB). Ten age-matched Wistar rats served as a non-diabetic control group (WIC). Glycemic control was assessed before and 4 weeks after surgery. Fasting- and mixed-meal-induced plasma levels of insulin and glucagon were measured. Overall glycemic control improved in GKSG and GKGB rats. Fasting insulin levels in WIC rats were similar to those for GKC or GKSS rats. Fasting glucagon levels were highest in GKGB rats. Whereas WIC, GKC, and GKSS rats showed similar glucagon levels, without any significant meal-induced variation, a significant rise occurred in GKSG and GKGB rats, 30 min after a mixed meal, which was maintained at 60 min. Both GKSG and GKGB rats showed an elevated glucagon:insulin ratio at 60 min in comparison with all other groups. Surprisingly, the augmented post-procedural glucagon secretion was accompanied by an improved overall glucose metabolism in GKSG and GKGB rats. Understanding the role of glucagon in the pathophysiology of type 2 diabetes requires further research.

Safety of saxagliptin: events of special interest in 9156 patients with type 2 diabetes mellitus

BACKGROUND

A post hoc pooled analysis was undertaken to evaluate the safety of saxagliptin in patients with type 2 diabetes mellitus, with attention to events of special interest for dipeptidyl peptidase-4 inhibitors.

METHODS

Pooled analyses were performed for 20 randomized controlled studies (N = 9156) of saxagliptin as monotherapy or add-on therapy, and a subset of 11 saxagliptin + metformin studies. Adverse events and events of special interest (gastrointestinal adverse events, infections, hypersensitivity, pancreatitis, skin lesions, lymphopenia, thrombocytopenia, hypoglycaemia, bone fracture, severe cutaneous adverse reactions, opportunistic infection, angioedema, malignancy, worsening renal function, and specific laboratory events) were assessed; incidence rates (events/100 person-years) and incidence rates ratios (saxagliptin/control) were calculated (Mantel-Haenszel method).

RESULTS

In both pooled datasets, the incidence rates for deaths, serious adverse events, discontinuations due to adverse events, pancreatitis, malignancy, and most other events of special interest, excepting bone fractures and hypersensitivity, were similar between treatments, with 95% confidence intervals (CIs) for incidence rates ratios including 1. In the 20-study pool, the incidence rates per 100 person-years was higher with saxagliptin versus control for bone fractures [1.1 vs 0.6; incidence rates ratio (95% CI), 1.81 (1.04-3.28)] and hypersensitivity adverse events [1.3 vs 0.8; 1.67 (1.01-2.87)].

CONCLUSIONS

Pooled data from 20 studies confirm that saxagliptin has a favourable safety and benefit-risk profile.

Exploratory trial of intranasal administration of glucagon-like peptide-1 in Japanese patients with type 2 diabetes

OBJECTIVE

This study aimed to assess the efficacy and safety of our newly developed nasal glucagon-like peptide-1 (GLP-1) compound and injector.

RESEARCH DESIGN AND METHODS

Twenty-six patients with type 2 diabetes were enrolled in this double-blind placebo-controlled study. The nasal compound containing 1.2 mg of human GLP-1 (7-36) amide or placebo was administered immediately before every meal for 2 weeks.

RESULTS

The plasma peak concentration of active GLP-1 was 47.2 pmol/L, and its Tmax was 8.1 min. The early phase of insulin and glucagon secretion were recovered and suppressed, respectively, in the GLP-1 group. Glycoalbumin levels became significantly lower and 1,5-anhydroglucitol levels significantly higher after GLP-1 administration. No marked adverse events were observed after using nasal GLP-1.

CONCLUSIONS

The newly developed nasal GLP-1 compound may be a potential treatment for type 2 diabetes. The long-term application of the drug should be evaluated in future trials.

Continuous subcutaneous delivery of exenatide via ITCA 650 leads to sustained glycemic control and weight loss for 48 weeks in metformin-treated subjects with type 2 diabetes

AIMS

Evaluate the efficacy and tolerability of ITCA 650 in subjects with type 2 diabetes treated for up to 48 weeks.

METHODS

This was a 24-week extension to a randomized, 24-week, open-label, phase 2 study in subjects with type 2 diabetes inadequately controlled with metformin. Subjects received ITCA 650 mg (20, 40, 60 or 80 μg/day). Mean changes for HbA1c, weight, and fasting plasma glucose (FPG) were evaluated.

RESULTS

Mean changes in HbA1c from baseline to week 48 ranged from -0.85% to -1.51%. At week 48, ≥64% of subjects with an HbA1c ≤7% at week 24 maintained an HbA1c ≤7%. The incidence of adverse events (AEs) was dose-related and ranged from 13.3% with 20 μg/day to 37.5% with 80 μg/day. Most AEs were mild and transient; the incidence of nausea declined from 12.9% to 9.5% over the 24-week extension. One subject on ITCA 650 80 μg/day experienced mild intermittent vomiting. Three (3.5%) subjects experienced severe AEs, but none were considered related to study drug.

CONCLUSION

Significant changes in HbA1c, body weight, and FPG attained with ITCA 650 were maintained to 48 weeks. The incidence of AEs was lower in the 24-week extension than in the initial 24-week treatment phase.

Comparative effectiveness of dipeptidyl peptidase-4 (DPP-4) inhibitors and human glucagon-like peptide-1 (GLP-1) analogue as add-on therapies to sulphonylurea among diabetes patients in the Asia-Pacific region: a systematic review

The prevalence of diabetes mellitus is rising globally, and it induces a substantial public health burden to the healthcare systems. Its optimal control is one of the most significant challenges faced by physicians and policy-makers. Whereas some of the established oral hypoglycaemic drug classes like biguanide, sulphonylureas, thiazolidinediones have been extensively used, the newer agents like dipeptidyl peptidase-4 (DPP-4) inhibitors and the human glucagon-like peptide-1 (GLP-1) analogues have recently emerged as suitable options due to their similar efficacy and favorable side effect profiles. These agents are widely recognized alternatives to the traditional oral hypoglycaemic agents or insulin, especially in conditions where they are contraindicated or unacceptable to patients. Many studies which evaluated their clinical effects, either alone or as add-on agents, were conducted in Western countries. There exist few reviews on their effectiveness in the Asia-Pacific region. The purpose of this systematic review is to address the comparative effectiveness of these new classes of medications as add-on therapies to sulphonylurea drugs among diabetic patients in the Asia-Pacific countries. We conducted a thorough literature search of the MEDLINE and EMBASE from the inception of these databases to August 2013, supplemented by an additional manual search using reference lists from research studies, meta-analyses and review articles as retrieved by the electronic databases. A total of nine randomized controlled trials were identified and described in this article. It was found that DPP-4 inhibitors and GLP-1 analogues were in general effective as add-on therapies to existing sulphonylurea therapies, achieving HbA1c reductions by a magnitude of 0.59-0.90% and 0.77-1.62%, respectively. Few adverse events including hypoglycaemic attacks were reported. Therefore, these two new drug classes represent novel therapies with great potential to be major therapeutic options. Future larger-scale research should be conducted among other Asia-Pacific region to evaluate their efficacy in other ethnic groups.

Nutritional management of type 2 diabetes mellitus and obesity and pharmacologic therapies to facilitate weight loss

Diet plays an integral role in the treatment of type 2 diabetes mellitus (T2DM). Unfortunately, many patients with T2DM do not have access to a registered dietitian or certified diabetes educator, and rates of physician counseling about diet remain low. This article provides an overview of the current recommendations for the nutritional management of T2DM, which are endorsed by the American Diabetes Association (ADA). Medical nutrition therapy, which provides a flexible and individualized approach to diet, emphasizes the total number (rather than the type) of carbohydrate consumed. Because fat intake also affects glycemia and cardiovascular risk, a reduction in daily mono- and polyunsaturated fat intake is recommended for most patients with T2DM. Weight loss plays an important adjunct role in treating patients with T2DM, because the majority of individuals with T2DM are overweight or obese. Patient lifestyle modification, which encompasses diet, physical activity, and behavioral therapy, can be used to facilitate weight loss in conjunction with several different dietary approaches. These include low-carbohydrate, low-fat, low-glycemic index, and Mediterranean diets. Studies have demonstrated that modest weight loss (5%-10% of body weight) is associated with significant improvements in patient measures of glycemic control, lipids, blood pressure, and other cardiovascular risk factors. Furthermore, a modest weight loss of as little as 4.5 kg can result in reducing the glycated hemoglobin level by approximately 0.5%. Pharmacologic agents, when combined with these approaches, may further augment weight loss. Familiarity with these principles can help physicians provide dietary counseling to their patients with T2DM and obesity.

Early use of glucagon-like peptide-1 receptor agonists (GLP-1 RAs) in type 2 diabetes

OBJECTIVE

To evaluate the efficacy and safety of the available glucagon-like peptide-1 receptor agonists (GLP-1 RAs) exenatide and liraglutide (marketed as Byetta * and Victoza † , respectively) in first- or second-line pharmacotherapy for type 2 diabetes (T2D), described here as 'early use'.

RESEARCH DESIGN AND METHODS

MEDLINE, EMBASE and Google Scholar databases were queried for clinical trial reports using the terms incretin, GLP-1, exenatide and liraglutide. Relevant articles were those that employed these agents in treatment-naïve patients with T2D and in patients who had failed on metformin monotherapy. Additional targeted searches were conducted on diabetes treatment guidelines and on the range of physiological responses to GLP-1 RAs. Most evidence is level I and II.

RESULTS

Effective therapy for T2D should be implemented early in the course of this progressive disease. The recently revised 2013 Canadian Diabetes Association (CDA) guidelines now identify the GLP-1 RAs among various injected and oral agents recommended for the management of T2D. The rationale for early use of GLP-1 RAs in T2D management is manifold: these agents offer effective management of hyperglycemia in early-stage T2D, minimal risk of hypoglycemia, weight loss, improvement in multiple non-glycemic cardiovascular risk factors, and potential enhancement of patient adherence to antihyperglycemic treatment. Available data from clinical trials support second-line use of GLP-1 RAs among patients who fail on metformin, as well as first-line use of these agents in a subset of T2D patients.

CONCLUSIONS

The ability to achieve glycemic targets using GLP-1 RAs while simultaneously avoiding hypoglycemia and weight gain could provide substantial reassurance to physicians and patients who might otherwise resist the transition to injected therapies. Exenatide and liraglutide represent appropriate second-line choices for pharmacological treatment of T2D, as indicated in the 2013 CDA guidelines.

The potential risks of pancreatitis and pancreatic cancer with GLP-1-based therapies are far outweighed by the proven and potential (cardiovascular) benefits

Recent suggestions that glucagon-like peptide-1 (GLP-1)-based therapies could cause pancreatitis, and even pancreatic cancer, are based on:

ANIMAL STUDIES

The worrying histological changes are not reproduced in all studies and are unexpectedly variable with different GLP-1-based therapies.

AN OBSERVATIONAL STUDY

Singh's findings that pancreatitis is doubled with GLP-1-based therapies could relate to their use in obese patients who are prone to pancreatitis risk factors--gallstones and hypertriglyceridaemia. The other observational studies do not find an association between GLP-1-based therapies and pancreatitis.

US FOOD AND DRUG ADMINISTRATION ADVERSE EVENT REPORTING SYSTEM

The increased reports of pancreatitis and pancreatic cancer are likely to be attributable to 'notoriety bias'.

A STUDY OF ORGAN DONOR PANCREASES

Butler's findings for those on GLP-1-based therapies vs. those not, could have other explanations. Meanwhile: META ANALYSIS: Randomized control trials with GLP-1-based therapies do not find increased pancreatitis risk. Meta-analysis of 53 randomized controlled trials including 20 212 dipeptidyl peptidase-4 inhibitor-treated patients found a significantly reduced risk of major adverse cardiovascular events [odds ratio 0.689 (0.528-0.899), P = 0.006] for dipeptidyl peptidase-4 inhibitors compared with control subjects.

CARDIOVASCULAR RISK

The evidence suggests that there is more than a possibility that some of the GLP-1 receptor agonists, and possibly also some dipeptidyl peptidase-4 inhibitors, may be associated with reduced cardiovascular events. Eight ongoing long-term cardiovascular randomized controlled trials will report from September 2013 onwards. These trials should resolve the issue of pancreatitis risk and substantiate the extent of benefit.

CONCLUSION

Whilst we should remain vigilant, currently the balance of evidence is strongly in support of GLP-1-based therapy, with benefits far outweighing potential risks.

Randomized trial of continuous subcutaneous delivery of exenatide by ITCA 650 versus twice-daily exenatide injections in metformin-treated type 2 diabetes

OBJECTIVE

To evaluate ITCA 650, a continuous subcutaneous miniature osmotic pump delivery system of exenatide versus twice-daily exenatide injections (Ex-BID) in subjects with type 2 diabetes.

RESEARCH DESIGN AND METHODS

We conducted a randomized, two-stage, 24-week, open-label, phase 2 study in type 2 diabetes inadequately controlled with metformin. Stage I: 155 subjects were randomized to 20 or 40 μg/day of ITCA 650 or Ex-BID 5 → 10 μg. Stage II: 131 subjects were rerandomized to 20, 40, 60, or 80 μg/day of ITCA 650. Change from baseline for HbA1c, weight, and fasting plasma glucose were evaluated at weeks 12 and 24.

RESULTS

HbA1c was significantly lower in all groups after 12 and 24 weeks. Stage I: mean change in HbA1c from a mean baseline of 7.9-8.0% was -0.98, -0.95, and -0.72% for the 20 and 40 μg/day ITCA 650 and Ex-BID groups, respectively, with 63, 65, and 50% of subjects achieving HbA1c levels ≤ 7% (P < 0.05). Stage II: significant (P < 0.05) reductions in HbA1c (≈ 1.4% from baseline) were achieved with 60 and 80 μg/day ITCA 650, and 86 and 78% of subjects achieved HbA1c ≤ 7% at 24 weeks; respectively. Weight was reduced by 2.8-3.7 kg (P < 0.05) at 24 weeks in all except the 20 → 20 μg/day group. ITCA 650 was well tolerated; nausea was lower and transient with 20 μg/day relative to Ex-BID; and 60 μg/day had the best profile of tolerability and HbA1c lowering.

CONCLUSIONS

ITCA 650 significantly reduced HbA1c and weight and was well tolerated. The 20 → 60 μg/day regimen was considered the best dose for further examination in phase 3.

Association of sulphonylurea treatment with all-cause and cardiovascular mortality: a systematic review and meta-analysis of observational studies

We conducted a meta-analysis of cohort and case-control studies to evaluate all-cause and cardiovascular (CV) mortality of patients with type 2 diabetes mellitus (T2DM) who received sulphonylurea (SU) treatment, when compared to any other diabetes treatment. Only studies reporting raw data on mortality during SU treatment were included. Data were combined using random-effects (RE) models. Unadjusted odds ratios (ORs) are presented. Of 4991 publication titles and abstracts reviewed, 20 studies (n = 551,912 patients) were included. For cohort studies (n = 276,050), patients receiving SU monotherapy or combination treatment had significantly higher all-cause and CV mortality risks compared to any non-SU treatment [all-cause, 13 studies: OR = 1.92, 95% confidence interval (CI) = 1.48-2.49; CV, 5 studies: OR = 2.72, 95% CI = 1.95-3.79]. Validity was limited by the high treatment group heterogeneity (I (2) > 90%) and study-inherent biases/design differences. In conclusion, patients receiving SU treatment had increased all-cause and CV mortality risks. However, the meta-analysis was limited by the high heterogeneity of non-randomized studies.

Glucagon-like peptides 1 and 2 in health and disease: a review

The gut derived peptides, glucagon-like peptides 1 and 2 (GLP-1 and GLP-2), are secreted following nutrient ingestion. GLP-1 and another gut peptide, glucose-dependent insulinotropic polypeptide (GIP) are collectively referred to as 'incretin' hormones, and play an important role in glucose homeostasis. Incretin secretion shares a complex interdependent relationship with both postprandial glycemia and the rate of gastric emptying. GLP-1 based therapies are now well established in the management of type 2 diabetes, while recent literature has suggested potential applications to treat obesity and protect against cardiovascular and neurological disease. The mechanism of action of GLP-2 is not well understood, but it shows promise as an intestinotropic agent.

Primary-care observational database study of the efficacy of GLP-1 receptor agonists and insulin in the UK

AIMS

We investigated use and efficacy of glucagon-like peptide-1 (GLP-1) receptor agonists in UK practice.

METHODS

People starting a GLP-1 receptor agonist (exenatide, liraglutide) or insulin (glargine, detemir, NPH) after a regimen of two or three oral glucose-lowering agents were identified from The Health Information Network observational primary care database (2007-2011). Mean change in HbA1c and body weight were compared at 1 year between cohorts, adjusting for baseline characteristics.

RESULTS

Baseline characteristics of GLP-1 receptor agonist (n = 1123) vs. insulin (n = 1842) users were HbA1c 78 vs. 84 mmol/mol (9.3 vs. 9.8%) and BMI 38.2 vs. 30.9 kg/m². The GLP-1 receptor agonist cohort was younger, had shorter diabetes duration and follow-up, less microvascular disease and heart failure, higher estimated glomerular filtration rate and more use of oral glucose-lowering agents. Lower HbA1c reduction on GLP-1 receptor agonist [7 vs. 13 mmol/mol (0.6 vs. 1.2%) (n = 366 vs. 892)] was not statistically significant [adjusted mean difference -1.4 (95% CI -4.1, 1.2) mmol/mol], except in the highest HbA1c quintile [>96 mmol/mol (>10.9%); adjusted mean difference -17.8 (-28.6, -7.0) mmol/mol]. GLP-1 receptor agonist users lost weight [-4.5 vs. +1.5 kg; adjusted mean difference 4.7 (3.7, 5.8) kg; n = 335 vs. 634]. A UK 6-month target reduction for GLP-1 receptor agonists of 11 mmol/mol (1.0%) HbA1c and 3% weight was reached by 24.9% of those continuing treatment.

CONCLUSIONS

Those starting GLP-1 receptor agonists are heavier with better glycaemic control than those starting basal insulin. Subsequently, they have improved weight change, with similar HbA1c reduction unless baseline HbA1c is very high. The UK 6-month GLP-1 receptor agonist target is usually not reached.

A network meta-analysis to compare glycaemic control in patients with type 2 diabetes treated with exenatide once weekly or liraglutide once daily in comparison with insulin glargine, exenatide twice daily or placebo

AIMS

The glucagon-like peptide-1 receptor agonists (GLP-1 RAs) exenatide once weekly (ExQW) and liraglutide once daily (QD) are indicated to improve glycaemic control in patients with type 2 diabetes. Although glycaemic control with ExQW versus liraglutide QD 1.8 mg has been directly compared, no studies have compared ExQW with liraglutide QD 1.2 mg or determined the probable relative efficacies of various injectable therapies for glycaemic control; therefore, a network meta-analysis was performed to address these questions.

METHODS

A systematic review identified randomized controlled trials of ≥24 weeks that compared ExQW, liraglutide QD (1.2 mg, 1.8 mg), insulin glargine, exenatide twice daily (ExBID), or placebo. Twenty-two studies evaluating 11 049 patients were included in the network meta-analysis. Mean differences in HbA1c relative to placebo or each other and probability rankings were estimated.

RESULTS

Estimated mean differences in HbA1c versus placebo were -1.15% (95% CrI: -1.31 to -1.00) for ExQW, -1.01% (95% CrI: -1.18 to -0.85) for liraglutide 1.2 mg, and -1.18% (95% CrI: -1.32 to -1.04) for liraglutide 1.8 mg. HbA1c differences for ExQW versus liraglutide 1.2 mg and 1.8 mg were -0.14% (95% CrI: -0.34 to 0.06) and 0.03% (95% CrI: -0.14 to 0.18), respectively. The estimated mean difference in HbA1c between liraglutide 1.2 mg and 1.8 mg was 0.17% (95% CrI: 0.02-0.30). Results were consistent when adjusted for background antihyperglycaemic medications and diabetes duration.

CONCLUSIONS

This network meta-analysis did not identify meaningful differences in HbA1c lowering between ExQW and both liraglutide doses, suggesting that these GLP-1 RAs have similar glycaemic effects.

Effect of low- and high-glycemic load on circulating incretins in a randomized clinical trial

OBJECTIVE

Low-glycemic load diets lower post-prandial glucose and insulin responses; however, the effect of glycemic load on circulating incretin concentrations is unclear. We aimed to assess effects of dietary glycemic load on fasting and post-prandial glucose, insulin and incretin (i.e., glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1)) concentrations and to examine for effect modification by adiposity.

MATERIALS AND METHODS

We conducted a single-center, randomized controlled crossover feeding trial in which a subset of participants had post-prandial testing. Participants were recruited from the local Seattle area. We enrolled 89 overweight-obese (BMI 28.0-39.9 kg/m(2)) and lean (BMI 18.5-25.0 kg/m(2)) healthy adults. Participants consumed two 28-day, weight-maintaining high- and low-glycemic load controlled diets in random order. Primary outcome measures were post-prandial circulating concentrations of glucose, insulin, GIP and GLP-1, following a test breakfast.

RESULTS

Of the 80 participants completing both diet interventions, 16 had incretin testing and comprise the group for analyses. Following each 28-day high- and low-glycemic load diet, mean fasting concentrations of insulin, glucose, GIP and GLP-1 were not significantly different. Mean integrated post-prandial concentrations of glucose, insulin and GIP were higher (1504±476 mg/dL/min, p<0.01; 2012±644 μU/mL/min, p<0.01 and 15517±4062 pg/mL/min, p<0.01, respectively) and GLP-1 was lower (-81.6±38.5 pmol/L/min, p<0.03) following the high-glycemic load breakfast as compared to the low-glycemic load breakfast. Body fat did not significantly modify the effect of glycemic load on metabolic outcomes.

CONCLUSIONS

High-glycemic load diets in weight-maintained healthy individuals lead to higher post-prandial GIP and lower post-prandial GLP-1 concentrations. Future studies evaluating dietary glycemic load manipulation of incretin effects would be helpful for establishing diabetes nutrition guidelines.

[Impact of anti-diabetic therapy based on glucagon-like peptide-1 receptor agonists on the cardiovascular risk of patients with type 2 diabetes mellitus]

Anti-diabetic drugs have, in addition to their well-known glucose lowering-effect, different effects in the rest of cardiovascular factors that are associated with diabetes mellitus. Glucagon-like peptide-1 (GLP-1) receptor agonists have recently been incorporated to the therapeutic arsenal of type 2 diabetes mellitus. The objective of this review is to summarize the available evidence on the effect of the GLP-1 receptor agonists on different cardiovascular risk factors, mediated by the effect of GLP-1 receptor agonists on the control of hyperglycaemia and the GLP-1 receptor agonists effect on other cardiovascular risk factors (weight control, blood pressure control, lipid profile and all other cardiovascular risk biomarkers). In addition, we present the emerging evidence with regards to the impact that GLP-1 receptor agonists therapy could have in the reduction of cardiovascular events and the currently ongoing studies addressing this issue.

Gender difference in response predictors after 1-year exenatide therapy twice daily in type 2 diabetic patients: a real world experience

PURPOSE

To investigate whether gender affects therapeutic response by exenatide twice a day (BID) in type 2 diabetes by using a database concerning patients monitored by five outpatient clinics in Tuscany, Italy.

PATIENTS AND METHODS

We considered a cohort of 315 (154 male/161 female) patients experiencing therapeutic failure while on oral therapy (metformin, or combination therapy metformin + sulphonylureas), who were given exenatide (10 μg/BID) and who fully completed 4 months, 8 months, and 12 months of follow-ups.

RESULTS

Among patients stratified by gender and well matched for age, body mass index, and hemoglobin A1c (HbA1c), it was found that the length of disease was longer in females than in males (12 ± 8 years versus 10 ± 7 years; P = 0.037), and the ratio of patients on metformin to those on combination therapy was higher in men (P = 0.018). Target glycemic response (1-year HbA1c ≤ 7%) was achieved in a significantly higher proportion of males than females (38% versus 27%; χ(2) = 4.66; P = 0.03). Target weight loss expressed as 1-year weight percent fall from baseline ≥ 75th percentile (8.5%) was significantly higher in females at 8 and 12 months (P < 0.05; for both). One-year glycemic target response was inversely related to baseline HbA1c levels and diabetes duration among males, while metformin therapy (compared to oral combination therapy) was a significant predictor of better glycemic targets among females. Homeostasis model assessment-B, measured in 117 patients, predicted hypoglycemic response only in women (P = 0.009). Target 1-year weight loss was predicted by longer diabetes duration among males and by lower baseline HbA1c among females. Finally, no significant difference between genders was noted as to gastrointestinal side effects after exenatide therapy.

CONCLUSION

According to this "real world" experience, predictors of glycemic control and body weight loss after 12 months of exenatide BID therapy are different between genders in type 2 diabetes.

Cardiovascular safety and glycemic control of glucagon-like peptide-1 receptor agonists for type 2 diabetes mellitus: a pairwise and network meta-analysis

AIMS

Integrating evidence from all randomized controlled trials (RCTs) of glucagon-like peptide-1 receptor agonists (GLP-1s) to assess the safety of cardiovascular disease (CVD) and efficacy of glycemic control.

METHODS

Besides performing pairwise meta-analysis, network meta-analysis of all RCTs was used to combine direct and indirect estimates of the effect of GLP-1 with placebo, active comparator drugs (ACD), or another GLP-1 agent with treatment duration ≥8 weeks in T2DM patients, 15,883 for CVD safety from 45 RCTs and 14,136 for glycemic control from 36 RCTs.

RESULTS

For CVD safety, both of the results from pairwise and network meta-analysis failed to demonstrate significant difference between any two comparators. For glycemic control, the effect of any GLP-1 was better than placebo, but no difference was found between GLP-1s. We also found that liraglutide was the only GLP-1 drug shown to be more effective on improving glycemic control than ACD and exenatide. The results based on direct or indirect estimates were similar for two outcomes.

CONCLUSION

Our network meta-analysis provides a complete picture of the associations between GLP-1s, ACD and placebo on CVD safety and glycemic control. The GLP-1s are promising candidates for the treatment of T2DM, but more long-term trials are needed to confirm potential CVD safety.

GLP-1 agonists for type 2 diabetes: pharmacokinetic and toxicological considerations

INTRODUCTION

Within recent years, glucagon-like peptide 1 receptor agonists (GLP-1-RA) have emerged as a new treatment option for type 2 diabetes. The GLP-1-RA are administered subcutaneously and differ substantially in pharmacokinetic profiles.

AREAS COVERED

This review describes the pharmacokinetics and safety aspects of the currently available GLP-1 receptor agonists, liraglutide (based on the structure of native GLP-1), exenatide twice daily and exenatide once weekly (based on exendin-4) in relation to the kinetics and toxicology of native GLP-1. The review is based on electronic literature searches and legal documents in the form of assessment reports from the European Medicines Agency and the United States Food and Drug Administration.

EXPERT OPINION

GLP-1-based therapy combines several unique mechanisms of action and have the potential to gain widespread use in the fight against diabetes and obesity. The difference in chemical structure have strong implications for key pharmacokinetic parameters such as absorption and clearance, and eventually the safety and efficacy of the individual GLP-1-RA. The main safety concerns are pancreatitis and neoplasms, for which there are no identifiable differences in risk between the available agents. Antibody formation and injection site reactions are more frequent with the exendin-4-based compounds. The efficacy with regard to Hb(A1c) reduction is superior with the longer-acting agonists, whereas the shorter-acting GLP-1-RA seems to provide greater postprandial glucose control and lower tolerability as a possible consequence of less induction of tachyphylaxis. The future place of these agents will depend on the added safety and efficacy data in the several ongoing cardiovascular outcome trials.

Choosing between GLP-1 Receptor Agonists and DPP-4 Inhibitors: A Pharmacological Perspective

In recent years the incretin therapies have provided a new treatment option for patients with type 2 diabetes mellitus (T2DM). The incretin therapies focus on the increasing levels of the two incretin hormones, glucagon-like peptide 1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP). This results in increased glucose dependent insulin synthesis and release. GLP-1 receptor agonists such as liraglutide and exenatide exert an intrinsic biological effect on GLP-1 receptors directly stimulating the release of insulin from pancreatic beta cells. DPP-4 inhibitors such as sitagliptin and linagliptin prevent the inactivation of endogenous GLP-1 and GIP through competitive inhibition of the DPP-4 enzyme. Both incretin therapies have good safety and tolerability profiles and interact minimally with a number of medications commonly prescribed in T2DM. This paper focuses on the pharmacological basis by which the incretin therapies function and how this knowledge can inform and benefit clinical decisions. Each individual incretin agent has benefits and pitfalls relating to aspects such as glycaemic and nonglycaemic efficacy, safety and tolerability, ease of administration, and cost. Overall, a personalized medicine approach has been found to be favourable, tailoring the incretin agent to benefit and suit patient's needs such as renal impairment (RI) or hepatic impairment (HI).

Recent advances in incretin-based therapies

The global burden of type 2 diabetes is growing. Traditional therapies are suboptimal and there is a clear unmet need for treatments that offer effective glucose control while addressing the comorbid factors associated with diabetes, such as obesity and risk of cardiovascular disease, without the fear of hypoglycaemia. Glucagon-like peptide-1 receptor agonists and dipeptidyl peptidase-4 inhibitors offer a novel way of reducing hyperglycaemia by targeting the incretin system. This review provides an overview of the development of incretin-based therapies and explains their differing modes of action compared with traditional interventions. A comparison of the clinical profiles of current glucagon-like peptide-1 receptor agonists [liraglutide and exenatide (twice-daily and once-weekly)] and dipeptidyl peptidase-4 inhibitors (sitagliptin, saxagliptin, vildagliptin and linagliptin) is performed alongside a discussion of the placement of incretin-based therapies in treatment guidelines. Further improvements in this class are expected, and we will examine some of the novel glucagon-like peptide-1 receptor agonists and dipeptidyl peptidase-4 inhibitors currently under development.