Review of head-to-head comparisons of glucagon-like peptide-1 receptor agonists

Comparison between insulin degludec/liraglutide treatment and insulin glargine/lixisenatide treatment in type 2 diabetes: a systematic review and meta-analysis

AIM

To evaluate the efficacy and adverse effects of IDegLira and IGlarLixi treatment and to perform a comparison between two strategies.

METHODS

The registration number is CRD42017053952. Randomized controlled trials of IGlarLixi treatment or IDegLira treatment compared with placebo or active hypoglycemic agents in type 2 diabetes were included.

RESULTS

Eight trials were included. The absolute HbA1c change relative to baseline after IGlarLixi treatment was -1.50% with significance (95% CI, -1.89% to -1.12%, p < 0.01); the absolute HbA1c change after IDegLira treatment was -1.89% with significance (95% CI, -2.04% to -1.73%, p < 0.01). Comparisons between IGlarLixi treatment and IDegLira treatment indicated no significant differences between groups. The absolute weight change after IGlarLixi treatment significantly decreased (weighted mean difference (WMD), -0.62 kg; 95% CI, -0.93 to -0.31 kg, p = < 0.01), but the absolute weight change after IDegLira treatment was not significantly changed (WMD, -0.81 kg; 95% CI, -3.26 to 1.65 kg, p = 0.52). There were no significant differences between groups.

CONCLUSION

Glucose control of IGlarLixi treatment or IDegLira treatment was significantly lower than that at baseline. Comparisons between the two treatment groups indicated no significant differences between groups in absolute HbA1c changes or body weight changes relative to baseline.

Protective effects of the GLP-1 mimetic exendin-4 in Parkinson's disease

There is increasing interest in the potential role of glucagon-like peptide-1 (GLP-1) receptor agonists as neuroprotective treatments in neurodegenerative diseases including Parkinson's disease following the publication of the results of the Exenatide-PD trial. Of the current GLP-1 receptor agonists already licensed to treat Type 2 diabetes several including exenatide, liraglutide and lixisenatide are the subject of ongoing clinical trials in PD. The underlying rationale for using drugs licensed and effective for T2DM in PD patients therefore needs to be scrutinized, and the results obtained to date critically reviewed. We review the relationship between insulin resistance and Parkinson's disease, the implications on pathogenesis and the efforts to reposition GLP-1 agonists as potential treatments for Parkinson's disease and give an overview of the pre-clinical and clinical data supporting the use of exenatide in Parkinson's disease with a discussion regarding possible mechanisms of action. This article is part of the Special Issue entitled 'Metabolic Impairment as Risk Factors for Neurodegenerative Disorders.'

A Hydrogel-Microsphere Drug Delivery System That Supports Once-Monthly Administration of a GLP-1 Receptor Agonist

We have developed a chemically controlled very long-acting delivery system to support once-monthly administration of a peptidic GLP-1R agonist. Initially, the prototypical GLP-1R agonist exenatide was covalently attached to hydrogel microspheres by a self-cleaving β-eliminative linker; after subcutaneous injection in rats, the peptide was slowly released into the systemic circulation. However, the short serum exenatide half-life suggested its degradation in the subcutaneous depot. We found that exenatide undergoes deamidation at Asn²⁸ with an in vitro and in vivo half-life of approximately 2 weeks. The [Gln²⁸]exenatide variant and exenatide showed indistinguishable GLP-1R agonist activities as well as pharmacokinetic and pharmacodynamic effects in rodents; however, unlike exenatide, [Gln²⁸]exenatide is stable for long periods. Two different hydrogel-[Gln²⁸]exenatide conjugates were prepared using β-eliminative linkers with different cleavage rates. After subcutaneous injection in rodents, the serum half-lives for the released [Gln²⁸]exenatide from the two conjugates were about 2 weeks and one month. Two monthly injections of the latter in the Zucker diabetic fatty rat showed pharmacodynamic effects indistinguishable from two months of continuously infused exenatide. Pharmacokinetic simulations indicate that the delivery system should serve well as a once-monthly GLP-1R agonist for treatment of type 2 diabetes in humans.

COMPARING CLINICAL OUTCOMES AND COSTS FOR DIFFERENT TREATMENT INTENSIFICATION APPROACHES IN PATIENTS WITH TYPE 2 DIABETES UNCONTROLLED ON BASAL INSULIN: ADDING GLUCAGON-LIKE PEPTIDE 1 RECEPTOR AGONISTS VERSUS ADDING RAPID-ACTING INSULIN OR INCREASING BASAL INSULIN DOSE

OBJECTIVE

Not all patients with type 2 diabetes achieve recommended glycated hemoglobin A_1c (A1C) levels after adequate titration of basal insulin (BI). Current intensification approaches include addition of rapid-acting insulin (RAI) or a glucagon-like peptide 1 receptor agonist (GLP-1 RA), but it is not clear which strategy results in better long-term outcomes.

METHODS

This retrospective analysis of health insurance claims data in the U.S. MarketScan database compared glycemic control and healthcare resource utilization and costs 12 months after adding a GLP-1 RA to BI versus adding a RAI or increasing BI doses. Propensity score matching was used in the comparative effectiveness analysis.

RESULTS

A total of 8,034 patients underwent treatment intensification within 6 months of showing poor glycemic control; 4,134 patients had their BI dose adjusted, and 2,076 and 331 received RAI and GLP-1 RA, respectively. A1C changes were similar for the GLP-1 RA and RAI cohorts but higher for the GLP-1 RA versus the dose-adjustment group. The hypoglycemia rate was lower after adding GLP-1 RA versus RAI or increasing BI dose. No overall changes in utilization of healthcare resources or diabetes-related costs were observed between intensification strategies, although prescription costs were higher for the GLP-1 RA cohort.

CONCLUSION

BI in combination with GLP-1 RAs appears to be an effective intensification strategy, further reducing A1C levels and hypoglycemia frequency compared to increasing BI doses. GLP-1 RA addition also decreases hypoglycemia frequency versus BI dose increases and RAI addition, without raising overall healthcare costs.

ABBREVIATIONS

A1C = hemoglobin A_1c; BI = basal insulin; CAD = coronary artery disease; ED = emergency department; FPG = fasting plasma glucose; GLP-1 RA = glucagon-like peptide 1 receptor agonist; ICD-9-CM = International Classification of Diseases, Ninth Revision, Clinical Modification; NPH = neutral protamine Hagedorn; OAD = oral antidiabetes drug; PSM = propensity score matching; RAI = rapid-acting insulin; T2D = type 2 diabetes.

Effects of semaglutide on beta cell function and glycaemic control in participants with type 2 diabetes: a randomised, double-blind, placebo-controlled trial

AIMS/HYPOTHESIS

Semaglutide is a glucagon-like peptide-1 analogue in development for the treatment of type 2 diabetes. Its effects on first- and second-phase insulin secretion and other measures of beta cell function and glycaemic control were assessed.

METHODS

In this single-centre, double-blind, placebo-controlled, parallel-group trial, conducted at the Profil Institut für Stoffwechselforschung, Germany, 75 adult (aged 18-64 years) participants with type 2 diabetes (eligibility: HbA1c of 6.5-9.0% (47.5-74.9 mmol/mol); BMI 20.0-35.0 kg/m2; and treatment with diet and exercise and/or metformin monotherapy with a dose unchanged in the 30 days prior to screening) were randomised (1:1) to once-weekly s.c. semaglutide 1.0 mg (0.25, 0.5, 1.0 mg escalated) or placebo for 12 weeks. Co-primary endpoints were changes from baseline to end of treatment in the first (AUC0-10 min) and second (AUC10-120 min) insulin secretion phases, as measured by the IVGTT. An arginine stimulation test (AST) and a 24 h meal stimulation test were also conducted. A graded glucose infusion test (GGIT) assessed insulin secretion rate (ISR) in treated participants and a group of untreated healthy participants. Safety endpoints were also assessed.

RESULTS

In total, 37 participants received semaglutide and 38 received placebo. Following IVGTT, for insulin, both AUC0-10min and AUC10-120min were significantly increased with semaglutide (estimated treatment ratio [95% CI] 3.02 [2.53, 3.60] and 2.10 [1.86, 2.37], respectively; p < 0.0001). The 24 h meal test showed reduced fasting, postprandial and overall (AUC0-24h) glucose and glucagon responses with semaglutide (p < 0.0001). The AST showed that maximal insulin capacity increased following semaglutide treatment. During GGIT, semaglutide significantly increased ISR to levels similar to those in healthy participants. Semaglutide was well tolerated.

CONCLUSIONS/INTERPRETATION

Twelve weeks of once-weekly treatment with semaglutide significantly improved beta cell function and glycaemic control in participants with type 2 diabetes.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02212067 FUNDING: The study was funded by Novo Nordisk A/S.

The safety of albiglutide for the treatment of type 2 diabetes

INTRODUCTION

Albiglutide is a marketed long acting GLP-1 receptor agonist (GLP-1 RA) administered by weekly injection. It has significantly less gastrointestinal side effects than other GLP-1 RAs in current use but does not improve HbA1c or promote weight loss to the same extent as competitor agents such as liraglutide. Area Covered: The safety of albiglutide is discussed. The review encompassed a search of PubMed and a thorough analysis of the European Union and US Food and Drug Administration approval documents. Expert Opinion: Unlike competitor agents, the gastrointestinal side effects of albiglutide are not much greater than placebo. It has been studied and appears safe at all stages of renal failure. There exists concern about an imbalance of pancreatitis cases in the approval program as well as injection site reactions which led to discontinuance of therapy in up to 2% of participants. A large long term study now underway will determine if albiglutide, with its relatively favorable GI tolerance, has a place in the treatment of patients with increased risk of cardiovascular events.

Glucose kinetics: an update and novel insights into its regulation by glucagon and GLP-1

PURPOSE OF REVIEW

Glucagon and GLP-1 share the same origin (i.e., proglucagon); primarily GLP-1 is generated from intestinal L-cells and glucagon from pancreatic α-cell, but intestinal glucagon and pancreatic GLP-1 secretion is likely. Glucose kinetics are tightly regulated by pancreatic hormones insulin and glucagon, but other hormones, including glucagon-like peptide-1 (GLP-1), also play an important role. The purpose of this review is to describe the recent findings on the mechanisms by which these two hormones regulate glucose kinetics.

RECENT FINDINGS

Recent findings showed new important mechanisms of action of glucagon and GLP-1 in the regulation of glucose metabolism. Knock out of glucagon receptors protects against hyperglycemia without causing hypoglycemia. GLP-1 not only stimulates insulin secretion, but it has also an independent effect on the liver and inhibits glucose production. Moreover, when coinfused with glucagon, GLP-1 limits the hyperglycemic effects. Both hormones have also central effects on gastric emptying (delayed), intestinal motility (reduced), and satiety (increased).

SUMMARY

The implications of these findings are very important for the management of type 2 diabetes given that GLP-1 receptor agonist are currently approved for the treatment of hyperglycemia and glucagon receptor antagonists and GLP-1/glucagon dual agonists are under development.

No cognitive-enhancing effect of GLP-1 receptor agonism in antipsychotic-treated, obese patients with schizophrenia

OBJECTIVE

Schizophrenia is associated with profound cognitive and psychosocial impairments. Glucagon-like peptide-1 receptor agonists (GLP-1RAs) are used for diabetes and obesity treatment, and animal studies have indicated cognitive-enhancing effects. In this investigator-initiated, double-blind, randomized, placebo-controlled trial, we tested non-metabolic effects of exenatide once-weekly (Bydureon™) in obese, antipsychotic-treated patients with schizohrenia spectrum disorder.

METHOD

Before and after 3 months of exenatide (N = 20) or placebo (N = 20) treatment, patients were assessed with the following: Brief Assessment of Cognition in Schizophrenia (BACS), Rey-Osterreith complex figure test (REY), Short-Form Health Survey (SF-36), Personal and Social Performance Scale (PSP) and the Positive and Negative Syndrome Scale (PANSS). We used BACS composite score as the main outcome measure.

RESULTS

Repeated measures analysis of variance on BACS composite score showed significant effect of 'Time' (P < 0.001), no effect of 'Group' (P = 0.64) and no 'Time*Group' interaction (P = 0.77). For REY, SF-36, PSP and PANSS, only significant 'Time' effects were found.

CONCLUSION

The non-significant results of this first clinical trial exploring non-metabolic effects of a long-acting GLP-1RA in patients with schizophrenia could reflect a general problem of translating cognitive-enhancing effects of GLP-1RAs from animals to humans or be explained by factors specifically related to schizophrenia spectrum patients with obesity such as antipsychotic treatment.

Effect of Liraglutide Treatment on Prediabetes and Overweight or Obesity in Clozapine- or Olanzapine-Treated Patients With Schizophrenia Spectrum Disorder: A Randomized Clinical Trial

Importance

Compared with the general population, patients with schizophrenia have a 2- to 3-fold higher mortality rate primarily caused by cardiovascular disease. Previous interventions designed to counteract antipsychotic-induced weight gain and cardiometabolic disturbances reported limited effects.

Objectives

To determine the effects of the glucagon-like peptide-1 receptor agonist liraglutide added to clozapine or olanzapine treatment of schizophrenia spectrum disorders.

Design, Setting, and Participants

This randomized clinical double-blind trial enrolled participants at 2 clinical sites in Denmark. Of 214 eligible participants with a schizophrenia spectrum disorder, 103 were randomized to liraglutide or placebo. Participants received stable treatment with clozapine or olanzapine, were overweight or obese, and had prediabetes. Data were collected from May 1, 2013, through February 25, 2016.

Interventions

Treatment for 16 weeks with once-daily subcutaneous injection of liraglutide or placebo. Trial drug therapy was titrated during the first 2 weeks of the study.

Main Outcomes and Measures

The primary end point was change in glucose tolerance estimated by a 75-g oral glucose tolerance test result. Secondary end points included change in body weight and cardiometabolic parameters.

Results

Of the 103 patients undergoing randomization (60 men [58.3%] and 43 women [41.7%]), 97 were included in the efficacy analysis, with a mean (SD) age of 42.5 (10.5) years and mean (SD) body mass index (calculated as weight in kilograms divided by height in meters squared) of 33.8 (5.9). The liraglutide and placebo groups had comparable characteristics (mean [SD] age, 42.1 [10.7] vs 43.0 [10.5] years; 30 men in each group; mean [SD] body mass index, 33.7 [5.1] vs 33.9 [6.6]). A total of 96 randomized participants (93.2%) completed the trial. Glucose tolerance improved in the liraglutide group compared with the placebo group (P < .001). Altogether, 30 liraglutide-treated participants (63.8%) developed normal glucose tolerance compared with 8 placebo-treated participants (16.0%) (P < .001; number needed to treat, 2). Body weight decreased with liraglutide compared with placebo (-5.3 kg; 95% CI, -7.0 to -3.7 kg). Reductions in waist circumference (-4.1 cm; 95% CI, -6.0 to -2.3 cm), systolic blood pressure (-4.9 mm Hg; 95% CI, -9.5 to -0.3 mm Hg), visceral fat (-250.19 g; 95% CI, -459.9 to -40.5 g), and low-density lipoprotein levels (-15.4 mg/dL; 95% CI, -23.2 to -7.7 mg/dL) occurred with liraglutide compared with placebo. Adverse events with liraglutide affected mainly the gastrointestinal tract.

Conclusions and Relevance

Liraglutide significantly improved glucose tolerance, body weight, and cardiometabolic disturbances in patients with schizophrenia spectrum disorders treated with clozapine or olanzapine.

Trial Registration

clinicaltrials.gov Identifier: NCT01845259.

Pharmacologic Management of Type 2 Diabetes Mellitus: Available Therapies

Choices for the treatment of type 2 diabetes mellitus (T2DM) have multiplied as our understanding of the underlying pathophysiologic defects has evolved. Treatment should target multiple defects in T2DM and follow a patient-centered approach that considers factors beyond glycemic control, including cardiovascular risk reduction. The American Association of Clinical Endocrinologists/American College of Endocrinology and the American Diabetes Association recommend an initial approach consisting of lifestyle changes and monotherapy, preferably with metformin. Therapy choices are guided by glycemic efficacy, safety profiles, particularly effects on weight and hypoglycemia risk, tolerability, patient comorbidities, route of administration, patient preference, and cost. Balancing management of hyperglycemia with the risk of hypoglycemia and consideration of the effects of pharmacotherapy on weight figure prominently in US-based T2DM recommendations, whereas less emphasis has been placed on the ability of specific medications to affect cardiovascular outcomes. This is likely because, until recently, specific glucose-lowering agents have not been shown to affect cardiorenal outcomes. The Empagliflozin Cardiovascular Outcome Event Trial in Type 2 Diabetes Mellitus Patients-Removing Excess Glucose (EMPA-REG OUTCOME), the Liraglutide Effect and Action in Diabetes: Evaluation of Cardiovascular Outcome Results (LEADER) trial, and the Trial to Evaluate Cardiovascular and Other Long-term Outcomes with Semaglutide in Subjects with Type 2 Diabetes 6 (SUSTAIN-6) recently showed a reduction in overall cardiovascular risk with empagliflozin, liraglutide, and semaglutide treatment, respectively. Moreover, empagliflozin has become the first glucose-lowering agent indicated to reduce the risk of cardiovascular death in adults with T2DM and established cardiovascular disease. Results from cardiovascular outcomes trials have prompted an update to the 2017 American Diabetes Association standards of care, which now recommend consideration of empagliflozin or liraglutide for patients with suboptimally controlled long-standing T2DM and established atherosclerotic cardiovascular disease because these agents have been shown to reduce cardiovascular and all-cause mortality when added to standard care.

Short-acting glucagon-like peptide-1 receptor agonists as add-on to insulin therapy in type 1 diabetes: A review

A large proportion of patients with type 1 diabetes do not reach their glycaemic target of glycated hemoglobin (HbA1c) <7.0% (53 mmol/mol) and, furthermore, an increasing number of patients with type 1 diabetes are overweight and obese. Treatment of type 1 diabetes is based on insulin therapy, which is associated with well-described and unfortunate adverse effects such as hypoglycaemia and increased body weight. Glucagon-like peptide-1 (GLP-1) receptor agonists (RAs) are the focus of increasing interest as a possible adjunctive treatment to insulin in type 1 diabetes because of their glucagonostatic and extrapancreatic effects. So far, the focus has mainly been on the long-acting GLP-1RAs, but the risk-benefit ratio emerging from studies evaluating the effect of long-acting GLP-1RAs as adjunctive therapy to insulin therapy in patients with type 1 diabetes has been disappointing. This might be attributable to a lack of glucagonostatic effect of these long-acting GLP-1RAs in type 1 diabetes, alongside development of tachyphylaxis to GLP-1-induced retardation of gastric emptying. In contrast, the short-acting GLP-1RAs seem to have a preserved and sustained effect on glucagon secretion and gastric emptying in patients with type 1 diabetes, which could translate into effective lowering of postprandial glucose excursions; however, these observations regarding short-acting GLP-1RAs are all derived from small open-label trials and should thus be interpreted with caution. In the present paper we review the potential role of GLP-1RAs, in particular short-acting GLP-1RAs, as add-on to insulin in the treatment of type 1 diabetes.

Pharmacologic Management of Type 2 Diabetes Mellitus: Available Therapies

Choices for the treatment of type 2 diabetes mellitus (T2DM) have multiplied as our understanding of the underlying pathophysiologic defects has evolved. Treatment should target multiple defects in T2DM and follow a patient-centered approach that considers factors beyond glycemic control, including cardiovascular risk reduction. The American Association of Clinical Endocrinologists/American College of Endocrinology and the American Diabetes Association recommend an initial approach consisting of lifestyle changes and monotherapy, preferably with metformin. Therapy choices are guided by glycemic efficacy, safety profiles, particularly effects on weight and hypoglycemia risk, tolerability, patient comorbidities, route of administration, patient preference, and cost. Balancing management of hyperglycemia with the risk of hypoglycemia and consideration of the effects of pharmacotherapy on weight figure prominently in US-based T2DM recommendations, whereas less emphasis has been placed on the ability of specific medications to affect cardiovascular outcomes. This is likely because, until recently, specific glucose-lowering agents have not been shown to affect cardiorenal outcomes. The Empagliflozin Cardiovascular Outcome Event Trial in Type 2 Diabetes Mellitus Patients-Removing Excess Glucose (EMPA-REG OUTCOME), the Liraglutide Effect and Action in Diabetes: Evaluation of Cardiovascular Outcome Results (LEADER) trial, and the Trial to Evaluate Cardiovascular and Other Long-term Outcomes with Semaglutide in Subjects with Type 2 Diabetes 6 (SUSTAIN-6) recently showed a reduction in overall cardiovascular risk with empagliflozin, liraglutide, and semaglutide treatment, respectively. Moreover, empagliflozin has become the first glucose-lowering agent indicated to reduce the risk of cardiovascular death in adults with T2DM and established cardiovascular disease. Results from cardiovascular outcomes trials have prompted an update to the 2017 American Diabetes Association standards of care, which now recommend consideration of empagliflozin or liraglutide for patients with suboptimally controlled long-standing T2DM and established atherosclerotic cardiovascular disease because these agents have been shown to reduce cardiovascular and all-cause mortality when added to standard care.

Efficacy and safety of once-weekly semaglutide versus once-daily insulin glargine as add-on to metformin (with or without sulfonylureas) in insulin-naive patients with type 2 diabetes (SUSTAIN 4): a randomised, open-label, parallel-group, multicentre, multinational, phase 3a trial

BACKGROUND

Several pharmacological treatment options are available for type 2 diabetes; however, many patients do not achieve optimum glycaemic control and therefore new therapies are necessary. We assessed the efficacy and safety of semaglutide, a glucagon-like peptide-1 (GLP-1) analogue in clinical development, compared with insulin glargine in patients with type 2 diabetes who were inadequately controlled with metformin (with or without sulfonylureas).

METHODS

We did a randomised, open-label, non-inferiority, parallel-group, multicentre, multinational, phase 3a trial (SUSTAIN 4) at 196 sites in 14 countries. Eligible participants were insulin-naive patients with type 2 diabetes, aged 18 years and older, who had insufficient glycaemic control with metformin either alone or in combination with a sulfonylurea. We randomly assigned participants (1:1:1) to either subcutaneous once-weekly 0·5 mg or 1·0 mg semaglutide (doses reached after following a fixed dose-escalation regimen) or once-daily insulin glargine (starting dose 10 IU per day, then titrated weekly to a pre-breakfast self-measured plasma glucose target of 4·0-5·5 mmol/L [72-99 mg/dL]) for 30 weeks. In all treatment groups, previous background metformin and sulfonylurea treatment was continued throughout the trial. We did the randomisation using an interactive voice or web response system. The primary endpoint was change in mean HbA_1c from baseline to week 30 and the confirmatory secondary endpoint was the change in mean bodyweight from baseline to week 30. We assessed efficacy and safety in the modified intention-to-treat population (mITT; all randomly assigned participants who were exposed to at least one dose of study drug) and used a margin of 0·3% to establish non-inferiority in HbA_1c reduction. This trial is registered with ClinicalTrials.gov, number NCT02128932.

FINDINGS

Between Aug 4, 2014, and Sept 3, 2015, we randomly assigned 1089 participants to treatment; the mITT population consisted of 362 participants assigned to 0·5 mg semaglutide, 360 to 1·0 mg semaglutide, and 360 to insulin glargine. 49 (14%) participants assigned to 0·5 mg semaglutide discontinued treatment prematurely, compared with 55 (15%) assigned to 1·0 mg semaglutide, and 26 (7%) assigned to insulin glargine. Most discontinuations were due to adverse events-mostly gastrointestinal with semaglutide, and others such as skin and subcutaneous tissue disorders (eg, rash, pruritus, and urticaria) with insulin glargine. From a mean baseline HbA_1c of 8·17% (SD 0·89), at week 30, 0·5 and 1·0 mg semaglutide achieved reductions of 1·21% (95% CI 1·10-1·31) and 1·64% (1·54-1·74), respectively, versus 0·83% (0·73-0·93) with insulin glargine; estimated treatment difference versus insulin glargine -0·38% (95% CI -0·52 to -0·24) with 0·5 mg semaglutide and -0·81% (-0·96 to -0·67) with 1·0 mg semaglutide (both p<0·0001). Mean bodyweight at baseline was 93·45 kg (SD 21·79); at week 30, 0·5 and 1·0 mg semaglutide achieved weight losses of 3·47 kg (95% CI 3·00-3·93) and 5·17 kg (4·71-5·66), respectively, versus a weight gain of 1·15 kg (0·70-1·61) with insulin glargine; estimated treatment difference versus insulin glargine -4·62 kg (95% CI -5·27 to -3·96) with 0·5 mg semaglutide and -6·33 kg (-6·99 to -5·67) with 1·0 mg semaglutide (both p<0·0001). Severe or blood glucose-confirmed hypoglycaemia was reported by 16 (4%) participants with 0·5 mg semaglutide and 20 (6%) with 1·0 mg semaglutide versus 38 (11%) with insulin glargine (p=0·0021 and p=0·0202 for 0·5 mg and 1·0 mg semaglutide vs insulin glargine, respectively). Severe hypoglycaemia was reported by two (<1%) participants with 0·5 mg semaglutide, five (1%) with 1·0 mg semaglutide, and five (1%) with insulin glargine. Six deaths were reported: four (1%) in the 0·5 mg semaglutide group (three cardiovascular deaths, one pancreatic carcinoma, which was assessed as being possibly related to study medication) and two (<1%) in the insulin glargine group (both cardiovascular death). The most frequently reported adverse events were nausea with semaglutide, reported in 77 (21%) patients with 0·5 mg and in 80 (22%) with 1·0 mg, and nasopharyngitis reported in 44 (12%) patients with insulin glargine.

INTERPRETATION

Compared with insulin glargine, semaglutide resulted in greater reductions in HbA_1c and weight, with fewer hypoglycaemic episodes, and was well tolerated, with a safety profile similar to that of other GLP-1 receptor agonists.

FUNDING

Novo Nordisk A/S.

Efficacy and safety of once-weekly semaglutide versus once-daily sitagliptin as an add-on to metformin, thiazolidinediones, or both, in patients with type 2 diabetes (SUSTAIN 2): a 56-week, double-blind, phase 3a, randomised trial

BACKGROUND

Semaglutide is a novel glucagon-like peptide-1 (GLP-1) analogue, suitable for once-weekly subcutaneous administration, in development for treatment of type 2 diabetes. We assessed the efficacy and safety of semaglutide versus the dipeptidyl peptidase-4 (DPP-4) inhibitor sitagliptin in patients with type 2 diabetes inadequately controlled on metformin, thiazolidinediones, or both.

METHODS

We did a 56-week, phase 3a, randomised, double-blind, double-dummy, active-controlled, parallel-group, multinational, multicentre trial (SUSTAIN 2) at 128 sites in 18 countries. Eligible patients were aged at least 18 years (or at least 20 years in Japan) and diagnosed with type 2 diabetes, with insufficient glycaemic control (HbA_1c 7·0-10·5% [53·0-91·0 mmol/mol]) despite stable treatment with metformin, thiazolidinediones, or both. We randomly assigned participants (2:2:1:1) using an interactive voice or web response system to 56 weeks of treatment with subcutaneous semaglutide 0·5 mg once weekly plus oral sitagliptin placebo once daily, subcutaneous semaglutide 1·0 mg once weekly plus oral sitagliptin placebo once daily, oral sitagliptin 100 mg once daily plus subcutaneous semaglutide placebo 0·5 mg once weekly, or oral sitagliptin 100 mg once daily plus subcutaneous semaglutide placebo 1·0 mg once weekly. The two oral sitagliptin 100 mg groups (with semaglutide placebo 0·5 mg and 1·0 mg) were pooled for the analyses. The primary endpoint was change in HbA_1c from baseline to week 56, assessed in the modified intention-to-treat population (all randomly assigned participants who received at least one dose of study drug); change in bodyweight from baseline to week 56 was the confirmatory secondary endpoint. Safety endpoints included adverse events and hypoglycaemic episodes. This trial is registered with ClinicalTrials.gov, number NCT01930188.

FINDINGS

Between Dec 2, 2013, and Aug 5, 2015, we randomly assigned 1231 participants; of the 1225 included in the modified intention-to-treat analysis, 409 received semaglutide 0·5 mg, 409 received semaglutide 1·0 mg, and 407 received sitagliptin 100 mg. Mean baseline HbA_1c was 8·1% (SD 0·93); at week 56, HbA_1c was reduced by 1·3% in the semaglutide 0·5 mg group, 1·6% in the semaglutide 1·0 mg group, and 0·5% with sitagliptin (estimated treatment difference vs sitagliptin -0·77% [95% CI -0·92 to -0·62] with semaglutide 0·5 mg and -1·06% [-1·21 to -0·91] with semaglutide 1·0 mg; p<0·0001 for non-inferiority and for superiority, for both semaglutide doses vs sitagliptin). Mean baseline bodyweight was 89·5 kg (SD 20·3); at week 56, bodyweight reduced by 4·3 kg with semaglutide 0·5 mg, 6·1 kg with semaglutide 1·0 mg, and 1·9 kg with sitagliptin (estimated treatment difference vs sitagliptin -2·35 kg [95% CI -3·06 to -1·63] with semaglutide 0·5 mg and -4·20 kg [-4·91 to -3·49] with semaglutide 1·0 mg; p<0·0001 for superiority, for both semaglutide doses vs sitagliptin). The proportion of patients who discontinued treatment because of adverse events was 33 (8%) for semaglutide 0·5 mg, 39 (10%) for semaglutide 1·0 mg, and 12 (3%) for sitagliptin. The most frequently reported adverse events in both semaglutide groups were gastrointestinal in nature: nausea was reported in 73 (18%) who received semaglutide 0·5 mg, 72 (18%) who received semaglutide 1·0 mg, and 30 (7%) who received placebo, and diarrhoea was reported in 54 (13%) who received semaglutide 0·5 mg, 53 (13%) who received semaglutide 1·0 mg, and 29 (7%) who received placebo. Seven (2%) patients in the semaglutide 0·5 mg group, two (<1%) in the semaglutide 1·0 mg group, and five (1%) in the sitagliptin group had blood-glucose confirmed hypoglycaemia. There were six fatal events (two in the semaglutide 0·5 mg group, one in the semaglutide 1·0 mg group, and three in the sitagliptin group); none were considered likely to be related to the trial drugs.

INTERPRETATION

Once-weekly semaglutide was superior to sitagliptin at improving glycaemic control and reducing bodyweight in participants with type 2 diabetes on metformin, thiazolidinediones, or both, and had a similar safety profile to that of other GLP-1 receptor agonists. Semaglutide seems to be an effective add-on treatment option for this patient population.

FUNDING

Novo Nordisk A/S.

Targeting endothelial metaflammation to counteract diabesity cardiovascular risk: Current and perspective therapeutic options

The association of obesity and diabetes, termed "diabesity", defines a combination of primarily metabolic disorders with insulin resistance as the underlying common pathophysiology. Cardiovascular disorders associated with diabesity represent the leading cause of morbidity and mortality in the Western world. This makes diabesity, with its rising impacts on both health and economics, one of the most challenging biomedical and social threats of present century. The emerging comprehension of the genes whose alteration confers inter-individual differences on risk factors for diabetes or obesity, together with the potential role of genetically determined variants on mechanisms controlling responsiveness, effectiveness and safety of anti-diabetic therapy underlines the need of additional knowledge on molecular mechanisms involved in the pathophysiology of diabesity. Endothelial cell dysfunction, resulting from the unbalanced production of endothelial-derived vascular mediators, is known to be present at the earliest stages of insulin resistance and obesity, and may precede the clinical diagnosis of diabetes by several years. Once considered as a mere consequence of metabolic abnormalities, it is now clear that endothelial dysfunctional activity may play a pivotal role in the progression of diabesity. In the vicious circle where vascular defects and metabolic disturbances worsen and reinforce each other, a low-grade, chronic, and 'cold' inflammation (metaflammation) has been suggested to serve as the pathophysiological link that binds endothelial and metabolic dysfunctions. In this paradigm, it is important to consider how traditional antidiabetic treatments (specifically addressing metabolic dysregulation) may directly impact on inflammatory processes or cardiovascular function. Indeed, not all drugs currently available to treat diabetes possess the same anti-inflammatory potential, or target endothelial cell function equally. Perspective strategies pointing at reducing metaflammation or directly addressing endothelial dysfunction may disclose beneficial consequences on metabolic regulation. This review focuses on existing and potential new approaches ameliorating endothelial dysfunction and vascular inflammation in the context of diabesity.

Glucagon-like Peptide-1 Receptor Agonist Treatment Attributes Important to Injection-Naïve Patients with Type 2 Diabetes Mellitus: A Multinational Preference Study

INTRODUCTION

Glucagon-like peptide-1 receptor agonists (GLP-1RAs) differ in efficacy, side effects, dosing frequency, and device-related attributes. This study assessed the relative importance of treatment-related attributes in influencing preferences for GLP-1RAs among injection-naïve patients with type 2 diabetes mellitus (T2DM).

METHODS

Injection-naïve T2DM patients from five countries completed a Web-based discrete choice experiment (DCE) survey. Patients chose between hypothetical treatment profiles reflecting important and differentiating attributes of GLP-1RAs. Eight attributes were included: efficacy, side effects, device size, needle size, titration, preparation, evidence of long-term efficacy/safety, and dosing frequency. Odds ratios (ORs) and 95% confidence intervals were calculated using a conditional logit model to indicate the likelihood of choosing a treatment with a given attribute level versus a reference attribute level. The influence of individual attributes when considering full treatment profiles was examined using exenatide once weekly (QW) and liraglutide once daily (QD) as case examples.

RESULTS

A total of 1482 patients with T2DM completed the DCE survey. Side effects, efficacy, and dosing frequency were the three most important attributes influencing preferences; needle size, device size, and required preparation were least important. Total sample analysis indicated that a profile of GLP-1RA approximating exenatide QW (single pen) was preferred over a profile approximating liraglutide QD (OR 3.36; p < 0.001), when efficacy was assumed to be equal.

CONCLUSION

The most influential drivers of treatment preferences for a hypothetical GLP-RA profile were side effects, efficacy, and dosing frequency among injection-naïve T2DM patients. Preference elicitation can promote patient-centered care and inform new generations of T2DM treatments, which can lead to improved adherence and health outcomes.

Glucagon-Like Peptide-1 Receptor Agonist Treatment Attributes Important to Injection-Experienced Patients with Type 2 Diabetes Mellitus: A Preference Study in Germany and the United Kingdom

INTRODUCTION

This study assessed the relative importance of treatment-related attributes in influencing patient preferences for glucagon-like peptide-1 receptor agonists (GLP-1RAs) among injection-experienced type 2 diabetes mellitus (T2DM) patients in Germany and the United Kingdom.

METHODS

T2DM patients experienced with injecting once-weekly (QW) exenatide or once-daily (QD) liraglutide completed an online discrete-choice experiment (DCE) survey. Patients chose between hypothetical blinded treatment profiles reflecting attributes of GLP-1RAs. The DCE survey included eight attributes: efficacy, side effects, device size, needle size, titration, injection preparation, long-term efficacy/safety, and dosing frequency. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using a conditional logit model indicating the likelihood of choosing a treatment with a given attribute level versus a reference attribute level.

RESULTS

510 GLP-1RA injection-experienced patients completed the survey; 45.3% respondents were being treated with exenatide QW and 54.7% respondents were being treated with liraglutide QD. In terms of GLP-1RA attributes, patients indicated a preference for a treatment with greater efficacy (i.e., a 1.5-point improvement in HbA1c) (OR 2.58; 95% CI 2.37, 2.80; p < 0.001), fewer side effects (OR 2.67; 95% CI 2.52, 2.82; p < 0.001), once-weekly rather than once-daily administration (OR 2.26; 95% CI 2.13, 2.39; p < 0.001), and the preparation required for a multi-use pen (OR 1.71; 95% CI 1.55, 1.88; p < 0.001). Needle size, device size, and titration were not significant drivers of patient preference.

CONCLUSIONS

Among GLP-1RA injection-experienced patients, key drivers of treatment preference for a hypothetical GLP-RA profile were side effects, efficacy, dosing frequency, and required preparation. Understanding patient preferences is important for optimizing treatment decision-making and improving treatment adherence.

FUNDING

AstraZeneca.

Oxyntomodulin analog and exendin-4 derivative lower plasma glucose in cattle

The present study was undertaken with the aim of examining whether and how exendin-4 (1-3) fragment, ie, Ex-4 (1-3) fragment, contributes to the regulation of glucose. An analog of oxyntomodulin (OXM) ([Gly², Glu³]-OXM), a glucagon analog ([Gly², Glu³]-glucagon), and two derivatives of Ex-4 (glucandin and [Gly², Glu³]-glucandin) were synthesized by substituting with Gly², Glu³ at the N-terminuses of OXM and glucagon and/or by attaching Ex-4 (30-39) amide at the C-terminus of glucagon. Effects of these peptides on plasma insulin and glucose concentrations were investigated in cattle by conducting 3 in vivo experiments. In all 3 experiments, 0.1% BSA saline was injected as a control. In experiment 1, glucandin (amino acid sequence was glucagon [1-29]-Ex-4 [30-39] amide) and [Gly², Glu³]-glucandin were injected at the dose rates of 5 μg/kg BW in 4-mo-old Holstein steers. Results showed that glucoregulatory effects of glucandin were similar to those of glucagon. [Gly², Glu³]-glucandin stimulated insulin secretion at 2 to 10 min and lowered glucose concentrations at 15 to 75 min. Experiment 2 was carried out to better understand the glucose-lowering potency of [Gly², Glu³]-glucandin, in comparison with Ex-4 and glucagon-like peptide-1 (GLP-1), using 4.5-mo-old Holstein steers. [Gly², Glu³]-glucandin was injected at dose rates of 0.3 μg/kg BW, 1.0 μg/kg BW, 3.2 μg/kg BW, and 6.4 μg/kg BW. Ex-4 and GLP-1 were injected at dose rates of 0.3 μg/kg BW. Results showed that the insulinotropic and glucose-lowering effects of [Gly², Glu³]-glucandin were not as potent as for Ex-4 and GLP-1, and the minimum effective dose of [Gly², Glu³]-glucandin to regulate plasma glucose concentrations was 3.2 μg/kg BW. In experiment 3, [Gly², Glu³]-OXM and [Gly², Glu³]-glucagon were injected at dose rates of 5 μg/kg BW in 5-mo-old Holstein steers. Both [Gly², Glu³]-OXM and [Gly², Glu³]-glucagon increased insulin concentration. [Gly², Glu³]-OXM potently lowered plasma glucose, but [Gly², Glu³]-glucagon did not change it. In summary, our findings clearly demonstrate that Ex-4 (1-3) fragment contributes to the regulation of glucose. [Gly², Glu³]-OXM and [Gly², Glu³]-glucandin are insulinotropic and glucose-lowering peptides. It was of interest that the substitution of the first 3 amino acids of OXM with Ex-4 (1-3) could reverse the upregulation of glucose by OXM into downregulation of glucose. In lowering glycemia, [Gly², Glu³]-OXM seemed almost as effective as Ex-4, and [Gly², Glu³]-glucandin was less profound than Ex-4. These findings contributed new insights into the hormonal regulation of glucose in ruminants. The action of [Gly², Glu³]-OXM and [Gly², Glu³]-glucandin might provide an advantage in glycemic control of insulin resistance in cattle and humans.

Novel strategies in the oral delivery of antidiabetic peptide drugs - Insulin, GLP 1 and its analogs

As diabetes is a complex disorder being a major cause of mortality and morbidity in epidemic rates, continuous research has been done on new drug types and administration routes. Up to now, a large number of therapeutic peptides have been produced to treat diabetes including insulin, glucagon-like peptide-1 (GLP-1) and its analogs. The most common route of administration of these antidiabetic peptides is parenteral. Due to several drawbacks associated with this invasive route, delivery of these antidiabetic peptides by the oral route has been a goal of pharmaceutical technology for many decades. Dosage form development should focus on overcoming the limitations facing oral peptides delivery as degradation by proteolytic enzymes and poor absorption in the gastrointestinal tract (GIT). This review focuses on currently developed strategies to improve oral bioavailability of these peptide based drugs; evaluating their advantages and limitations in addition to discussing future perspectives on oral peptides delivery. Depending on the previous reports and papers, the area of nanocarriers systems including polymeric nanoparticles, solid lipid nanoparticles, liposomes and micelles seem to be the most promising strategy that could be applied for successful oral peptides delivery; but still further potential attempts are required to be able to achieve the FDA approved oral antidiabetic peptide delivery system.

Glucagon-Like Peptide-1 and Its Class B G Protein-Coupled Receptors: A Long March to Therapeutic Successes

The glucagon-like peptide (GLP)-1 receptor (GLP-1R) is a class B G protein-coupled receptor (GPCR) that mediates the action of GLP-1, a peptide hormone secreted from three major tissues in humans, enteroendocrine L cells in the distal intestine, α cells in the pancreas, and the central nervous system, which exerts important actions useful in the management of type 2 diabetes mellitus and obesity, including glucose homeostasis and regulation of gastric motility and food intake. Peptidic analogs of GLP-1 have been successfully developed with enhanced bioavailability and pharmacological activity. Physiologic and biochemical studies with truncated, chimeric, and mutated peptides and GLP-1R variants, together with ligand-bound crystal structures of the extracellular domain and the first three-dimensional structures of the 7-helical transmembrane domain of class B GPCRs, have provided the basis for a two-domain-binding mechanism of GLP-1 with its cognate receptor. Although efforts in discovering therapeutically viable nonpeptidic GLP-1R agonists have been hampered, small-molecule modulators offer complementary chemical tools to peptide analogs to investigate ligand-directed biased cellular signaling of GLP-1R. The integrated pharmacological and structural information of different GLP-1 analogs and homologous receptors give new insights into the molecular determinants of GLP-1R ligand selectivity and functional activity, thereby providing novel opportunities in the design and development of more efficacious agents to treat metabolic disorders.

Is there a justification for classifying GLP-1 receptor agonists as basal and prandial?

Several GLP-1 receptor agonists are currently available for treatment of type 2 diabetic patients. Based on their pharmacokinetic/pharmacodynamic profile, these drugs are classified as short-acting GLP-1 receptor agonists (exenatide and lixisenatide) or long-acting GLP-1 receptor agonists (exenatide-LAR, liraglutide, albiglutide, and dulaglutide). In clinical practice, they are also classified as basal or prandial GLP-1 receptor agonists to differentiate between patients who would benefit more from one or another based on characteristics such as previous treatment and the predominance of fasting or postprandial hyperglycemia. In the present article we examine available data on the pharmacokinetic characteristics of the various GLP-1 agonists and compare their effects with respect to the main parameters used to evaluate glycemic control. The article also analyzes whether the differences between the different GLP-1 agonists justify their classification as basal or prandial.

Safety and tolerability of glucagon-like peptide-1 receptor agonists: unresolved and emerging issues

INTRODUCTION

Glucagon-like peptide-1 receptor agonists (GLP-1 RAs) are a mainstay of treatment options for type 2 diabetes. They contribute to lowering blood glucose levels, generally have a favorable tolerability profile, and can be used alone or in combination with other antidiabetic agents. Based on the duration of their effects, GLP-1 RAs can be divided into two classes: short-acting and long-acting. Differences exist between these sub-classes, and between each drug, in terms of pharmacokinetic and pharmacodynamic profiles. Therefore, prescribers cannot necessarily assume GLP-1 RA 'class effects', especially in terms of tolerability. Areas covered: This article reviews the published data on the safety and tolerability of currently available GLP-1 RAs and, recognizing the importance of safety profiles when selecting the appropriate treatment for each patient, examines the clinical implications of the differences between the drugs in this class. Cardiovascular safety, gastrointestinal tolerability, and tolerability in elderly patients are discussed as specific areas of interest to prescribers selecting between GLP-1 RAs for their patients. Expert opinion: Although further research is needed, the current evidence offers the potential to tailor treatment more accurately to each patient. Ultimately, this may improve adherence and persistence, thereby improving glycemic control and, in turn, reducing the risk of macro- and micro-vascular complications.

Initiation and Intensification Strategies in Type 2 Diabetes Management: A Comparison of Basal Plus and Premix Regimens

The progressive nature of type 2 diabetes (T2D) often results in the need for initiation and subsequent intensification of insulin treatment to achieve glycemic control. The aim of this review is to examine published clinical evidence that has directly compared two recommended treatment approaches in patients with T2D: (1) a 'basal plus' regimen, whereby 1-2 injections of prandial insulin are added to basal insulin; or (2) the use of once- or twice-daily premix insulin analogs, which contain both basal and prandial insulin in a single injection. Broadly, the available evidence suggests that both basal plus and premix regimens are comparable in terms of efficacy and safety when used for insulin initiation in insulin-naïve patients and intensification in patients who have failed on basal insulin; instances of greater glycemic control are observed with premix insulin; however, these are often accompanied by increases in hypoglycemia and/or weight relative to basal plus treatment, and results should be interpreted within the context of total insulin doses used. Relatively low numbers of patients achieved glycemic control when both regimens were used for insulin intensification following failure of basal insulin, suggesting that a full basal-bolus regimen and/or the use of different treatments is clinically indicated in certain patients. In summary, the current review argues that both basal plus and premix insulin regimens are relatively efficacious and safe options for patients with T2D during both insulin initiation in insulin-naïve patients and intensification in patients who have failed on basal insulin. This emphasizes the important role of patient-centered factors in clinical decision-making.

FUNDING

Novo Nordisk.

A Plethora of GLP-1 Agonists: Decisions About What to Use and When

Incretin-based therapies are important addition to our armamentarium for the treatment of type 2 diabetes (T2DM). There are six Glucagon-like peptide-1 receptor agonists (GLP-1RAs) which have received regulatory approval for clinical use. The short-acting GLP-1RAs include exenatide twice daily, liraglutide once daily, and lixisenatide once daily. The approved long-acting GLP-1RAs are administered weekly and are exenatide, albiglutide, and dulaglutide. Although all of these therapies lower hemoglobin A1C (HbA1C), there also are unique features of GLP-1RAs that have been made manifest from clinical trial data with regard to weight-loss efficacy, fasting and post-prandial glucose control, cardiovascular safety and protection, and gastrointestinal and injection adverse effects. It is imperative to consider these features when tailoring the choice of a GLP-1RA to patient specific characteristics.

Liraglutide for treating type 1 diabetes

INTRODUCTION

Many persons with type 1 diabetes do not achieve glycemic targets, why new treatments, complementary to insulin, are of interest. Liraglutide, a long-acting glucagon-like peptide-1 receptor agonist could be a potential pharmacological supplement to insulin. This review discusses the mechanism of actions, efficacy and safety of liraglutide as add-on to insulin in persons with type 1 diabetes.

AREAS COVERED

Physiological and clinical data on liraglutide in type 1 diabetes were reviewed. We searched the Cochrane library, MEDLINE and EMBASE, with the final search performed February 16, 2016.

EXPERT OPINION

Liraglutide as adjunct to insulin treatment reduced body weight and daily dose of insulin compared with insulin alone. The effect on HbA1c was inconsistent with mostly uncontrolled, small-scale studies reporting improvements in glycemic control. In placebo-controlled studies there was no clinically relevant effect on HbA1c. Adverse events were mostly transient gastrointestinal side effects, primarily nausea. Based on the available data, liraglutide cannot be recommended as add-on therapy to insulin in persons with type 1 diabetes with the aim to improve glycemic control. Ongoing trials in newly diagnosed patients with type 1 diabetes and in insulin pump-treated patients will help define the future role of liraglutide therapy in type 1 diabetes.

Update on the treatment of type 2 diabetes mellitus

To achieve good metabolic control in diabetes and keep long term, a combination of changes in lifestyle and pharmacological treatment is necessary. Achieving near-normal glycated hemoglobin significantly, decreases risk of macrovascular and microvascular complications. At present there are different treatments, both oral and injectable, available for the treatment of type 2 diabetes mellitus (T2DM). Treatment algorithms designed to reduce the development or progression of the complications of diabetes emphasizes the need for good glycaemic control. The aim of this review is to perform an update on the benefits and limitations of different drugs, both current and future, for the treatment of T2DM. Initial intervention should focus on lifestyle changes. Moreover, changes in lifestyle have proven to be beneficial, but for many patients is a complication keep long term. Physicians should be familiar with the different types of existing drugs for the treatment of diabetes and select the most effective, safe and better tolerated by patients. Metformin remains the first choice of treatment for most patients. Other alternative or second-line treatment options should be individualized depending on the characteristics of each patient. This article reviews the treatments available for patients with T2DM, with an emphasis on agents introduced within the last decade.

Targeting the gastrointestinal tract to treat type 2 diabetes

The rising global rates of type 2 diabetes and obesity present a significant economic and social burden, underscoring the importance for effective and safe therapeutic options. The success of glucagon-like-peptide-1 receptor agonists in the treatment of type 2 diabetes, along with the potent glucose-lowering effects of bariatric surgery, highlight the gastrointestinal tract as a potential target for diabetes treatment. Furthermore, recent evidence suggests that the gut plays a prominent role in the ability of metformin to lower glucose levels. As such, the current review highlights some of the current and potential pathways in the gut that could be targeted to improve glucose homeostasis, such as changes in nutrient sensing, gut peptides, gut microbiota and bile acids. A better understanding of these pathways will lay the groundwork for novel gut-targeted antidiabetic therapies, some of which have already shown initial promise.

Investigational glucagon-like peptide-1 agonists for the treatment of obesity

INTRODUCTION

Obesity is a worldwide problem predisposing to type 2 diabetes mellitus (T2DM), hypertension, cardiovascular disease, cancer and other comorbidities. Lifestyle modification is the first line intervention but adjunctive pharmacotherapy is often required. The GLP-1 receptor agonists (GLP-1RAs) were developed primarily for T2DM and they also reduce body weight. Liraglutide was approved for the treatment of obesity and other GLP-1RAs are likely to be suitable for this indication.

AREAS COVERED

This review describes the GLP-1RAs that have been approved for the treatment of T2DM as potential candidates for the treatment of obesity and the new agents currently under development which may have advantages in patient adherence.

EXPERT OPINION

The GLP-1RAs offer a welcome addition to obesity pharmacotherapy. They appear to be free of serious adverse effects although uncertainty remains about possible risks of pancreatitis and neoplasms. However, they have frequent gastrointestinal side effects, particularly nausea, which limits their tolerability. Cardiovascular outcome studies in T2DM support their use and this is likely to increase in both T2DM and obesity. Other GLP-1RAs which can be given by subcutaneous injection once weekly or less frequently or by oral administration would have advantages especially if nausea is less frequent than with liraglutide.

A review of glycemic efficacy of liraglutide once daily in achieving glycated hemoglobin targets compared with exenatide twice daily, or sitagliptin once daily in the treatment of type 2 diabetes

Incretin-based therapies such as glucagon-like peptide-1 (GLP-1) receptor agonists (RA) and dipeptidyl peptidase-4 (DPP-4) inhibitors have gained prominence in recent years for the treatment of type 2 diabetes (T2D). Such therapies offer the potential to stimulate endogenous insulin activity in proportion to circulating glucose levels; thereby, lowering the risk of hypoglycemic episodes. The synthetic GLP-1 RA exenatide, the human GLP-1 RA liraglutide, and the DPP-4 inhibitor sitagliptin are the first agents in their respective classes to be approved for the treatment of T2D and their efficacy and safety has been studied extensively in clinical trials. This article reviewed the efficacy of liraglutide once daily in achieving clinical guidelines-recommended glycated hemoglobin A1c levels in patients with T2D compared with exenatide twice daily, or sitagliptin once daily, based on published literature, with an aim to elucidate the preferred choice of incretin-related therapy in treating uncontrolled T2D.

SGLT2 Inhibition and cardiovascular events: why did EMPA-REG Outcomes surprise and what were the likely mechanisms?

While the modest reduction in the primary composite outcome of myocardial infarction, stroke or cardiovascular death in the EMPA-REG Outcomes trial was welcome, the 30-40% reductions in heart failure hospitalisation (HFH) and cardiovascular and all-cause deaths in patients treated with empagliflozin were highly impressive and unexpected. In this review, we discuss briefly why cardiovascular endpoint trials for new diabetes agents are required and describe the results of the first four such trials to have reported, as a precursor to understanding why the EMPA-REG Outcomes results came as a surprise. Thereafter, we discuss potential mechanisms that could explain the EMPA-REG Outcomes results, concentrating on non-atherothrombotic effects. We suggest that the main driver of benefit may derive from the specific effects of sodium-glucose linked transporter-2 (SGLT2) inhibition on renal sodium and glucose handling, leading to both diuresis and improvements in diabetes-related maladaptive renal arteriolar responses. These haemodynamic and renal effects are likely to be beneficial in patients with clinical or subclinical cardiac dysfunction. The net result of these processes, we argue, is an improvement in cardiac systolic and diastolic function and, thereby, a lower risk of HFH and sudden cardiac death. We also discuss whether other drugs in this class are likely to show similar cardiovascular benefits. Finally, areas for future research are suggested to better understand the relevant mechanisms and to identify other groups who may benefit from SGLT2 inhibitor therapy.

Endoplasmic reticulum stress and the unfolded protein response in pancreatic islet inflammation

Insulin-secreting pancreatic β-cells are extremely dependent on their endoplasmic reticulum (ER) to cope with the oscillatory requirement of secreted insulin to maintain normoglycemia. Insulin translation and folding rely greatly on the unfolded protein response (UPR), an array of three main signaling pathways designed to maintain ER homeostasis and limit ER stress. However, prolonged or excessive UPR activation triggers alternative molecular pathways that can lead to β-cell dysfunction and apoptosis. An increasing number of studies suggest a role of these pro-apoptotic UPR pathways in the downfall of β-cells observed in diabetic patients. Particularly, the past few years highlighted a cross talk between the UPR and inflammation in the context of both type 1 (T1D) and type 2 diabetes (T2D). In this article, we describe the recent advances in research regarding the interplay between ER stress, the UPR, and inflammation in the context of β-cell apoptosis leading to diabetes.

Perspectives in GLP-1 Research: New Targets, New Receptors

The incretin hormone glucagon-like peptide-1 (GLP-1) binds to and activates its G-protein-coupled-receptor GLP-1R to reduce glycaemia through the stimulation of insulin and suppression of pancreatic glucagon secretion. Recently, GLP-1 effects unrelated to glucose homeostasis have been discovered in myocardium, bone, adipose tissue, and other target organs, which appear to be mainly mediated by GLP-1R-independent pathways. Here, we summarize knowledge on GLP-1R agonists (GLP-1RAs) as they relate to the improvement of glucose control, and focus on the most recently described effects, discussing the preclinical evidence of the involvement of alternative receptors and signalling mechanisms. It is now evident that the universe of GLP-1RAs is expanding further from the initial incretin effect, opening new unforeseen avenues for research and clinical applications.

Exenatide inhibits fatty acid induced hepatocyte steatosis and inflammation through activating AMPK

AIM: To detect the effect of glucagon-like peptide-1 (GLP-1) agonist exenatide (EXE) on fat deposition in liver cells and explore the underlying mechanism.

METHODS: A HepG2 cell deposition model was induced with palmitic acid (PA). After cells were incubated with different doses of EXE (25-100 nmoL/L) and PA (500 μmoL/L) for 24 h, fatty deposition was assessed by oil red O staining and the level of intracellular triglyceride (TG). Real-time quantitative PCR (qRT-PCR) was used to detect the expression of lipid metabolism related genes, including fatty acid synthase (FAS), tumor necrosis factor α (TNF-α), and interleukin 6 (IL-6). The expression of p-AMPK and AMPK protein was tested by Western blot. An AMPK inhibitor was used to explore the role of AMPK in fat deposition and inflammation.

RESULTS: Compared with the control group, PA significantly elevated TG and oil red O content, as well as the expression of FAS in HepG2 cells (P < 0.05). EXE significantly inhibited PA induced elevation of TG and oil red O content, as well as FAS gene expression in a dose dependent manner (P < 0.05). The expression of TNF-α and IL-6 significantly increased in the PA treated group (P < 0.05). EXE significantly inhibited the expression of TNF-α and IL-6 in PA treated HepG2 cells (P < 0.05). Co-treatment with AMPK inhibitor significantly reduced the effect of EXE on AMPK, and reduced the inhibitory effect of EXE on fatty deposition and PA induced FAS activation (P < 0.05). AMPK inhibitor significantly diminished the inhibitory effect of EXE on TNF-α and IL-6 activation induced by PA (P < 0.05).

CONCLUSION: EXE reduces fatty acid induced fatty deposition and inflammatory response in liver cells through activation of AMPK.

A Network Meta-analysis Comparing Exenatide Once Weekly with Other GLP-1 Receptor Agonists for the Treatment of Type 2 Diabetes Mellitus

INTRODUCTION

Exenatide is a glucagon-like peptide-1 receptor agonist (GLP-1 RA), approved for treatment of type 2 diabetes mellitus (T2DM). There is limited direct evidence comparing the efficacy and tolerability of exenatide 2 mg once weekly (QW) to other GLP-1 RAs. A network meta-analysis (NMA) was conducted to estimate the relative efficacy and tolerability of exenatide QW versus other GLP-1 RAs for the treatment of adults with T2DM inadequately controlled on metformin monotherapy.

METHODS

A systematic literature review was conducted to identify randomized controlled trials (RCTs) that investigated GLP-1 RAs (albiglutide, dulaglutide, exenatide, liraglutide, and lixisenatide) at approved doses in the United States/Europe, added on to metformin only and of 24 ± 6 weeks treatment duration. A Bayesian NMA was conducted.

RESULTS

Fourteen RCTs were included in the NMA. Exenatide QW obtained a statistically significant reduction in glycated hemoglobin (HbA1c) relative to lixisenatide 20 µg once daily. No other comparisons of exenatide QW to other GLP-1 RAs were statistically significant for change in HbA1c. No statistically significant differences in change in weight, systolic blood pressure, risk of nausea or discontinuation due to adverse events were observed for exenatide QW versus other GLP-1 RAs.

CONCLUSION

Exenatide QW demonstrated similar effectiveness and tolerability compared to other GLP-1 RAs, for the treatment of T2DM in adults inadequately controlled on metformin alone.