The effects of LY2189265, a long-acting glucagon-like peptide-1 analogue, in a randomized, placebo-controlled, double-blind study of overweight/obese patients with type 2 diabetes: the EGO study

Effects of the once-weekly glucagon-like peptide-1 receptor agonist dulaglutide on ambulatory blood pressure and heart rate in patients with type 2 diabetes mellitus

Glucagon-like peptide-1 receptor agonists, used to treat type 2 diabetes mellitus, are associated with small reductions in systolic blood pressure (SBP) and increases in heart rate. However, findings based on clinic measurements do not adequately assess a drug's 24-hour pharmacodynamic profile. The effects of dulaglutide, a once-weekly glucagon-like peptide-1 receptor agonist, on BP and heart rate were investigated using ambulatory BP monitoring. Patients (n=755; 56±10 years; 81% white; 48% women), with type 2 diabetes mellitus, taking ≥1 oral antihyperglycemic medication, with a clinic BP between 90/60 and 140/90 mm Hg were randomized to dulaglutide (1.5 or 0.75 mg) or placebo subcutaneously for 26 weeks. Ambulatory BP monitoring was performed at baseline and at 4, 16, and 26 weeks. The primary end point was change from baseline to week 16 in mean 24-hour SBP, a tree gatekeeping strategy compared the effects of dulaglutide to placebo. Both doses of dulaglutide were noninferior to placebo for changes in 24-hour SBP and diastolic blood pressure, and dulaglutide 1.5 mg significantly reduced SBP (least squares mean difference [95% confidence interval]), -2.8 mm Hg [-4.6, -1.0]; P≤0.001). Dulaglutide 0.75 mg was noninferior to placebo (1.6 bpm; [0.3, 2.9]; P≤0.02) for 24-hour heart rate (least squares mean difference [95% confidence interval]), but dulaglutide 1.5 mg was not (2.8 bpm [1.5, 4.2]). Dulaglutide 1.5 mg was associated with a reduction in 24-hour SBP and an increase in 24-hour heart rate. The mechanisms responsible for the observed effects remain to be clarified.

Action and therapeutic potential of oxyntomodulin

Oxyntomodulin (OXM) is a peptide hormone released from the gut in post-prandial state that activates both the glucagon-like peptide-1 receptor (GLP1R) and the glucagon receptor (GCGR) resulting in superior body weight lowering to selective GLP1R agonists. OXM reduces food intake and increases energy expenditure in humans. While activation of the GCGR increases glucose production posing a hyperglycemic risk, the simultaneous activation of the GLP1R counteracts this effect. Acute OXM infusion improves glucose tolerance in T2DM patients making dual agonists of the GCGR and GLP1R new promising treatments for diabetes and obesity with the potential for weight loss and glucose lowering superior to that of GLP1R agonists.

Glucagon-like peptide-1 receptor agonists for the treatment of type 2 diabetes: differences and similarities

Glucagon-like peptide-1 (GLP-1) is a gastrointestinal hormone, secreted in response to ingestion of nutrients, and has important effects on several of the pathophysiological features of type 2 diabetes (T2D). The effects include potentiation of insulin secretion, suppression of glucagon secretion, slowing of gastric emptying and suppression of appetite. In circulation, GLP-1 has a half-life of approximately 2min due to rapid degradation by the enzyme dipeptidyl peptidase 4 (DPP-4). Because of this short half-life GLP-1 receptor (GLP-1R) agonists, resistant to degradation by DPP-4 have been developed. At the moment four different compounds are available for the treatment of T2D and many more are in clinical development. These compounds, although all based on the effects of native GLP-1, differ with regards to structure, pharmacokinetics and size, which ultimately leads to different clinical effects. This review gives an overview of the clinical data on GLP-1R agonists that have been compared in head-to-head studies and focuses on relevant differences between the compounds. Highlighting these similarities and differences could be beneficial for physicians in choosing the best treatment strategy for their patients.

Choosing Appropriate Glucagon-like Peptide 1 Receptor Agonists: A Patient-Centered Approach

The individualized treatment of type 2 diabetes mellitus, using various glucagon-like peptide receptor agonists (GLP1RAs), has recently been described. As experience with existing GLP1RAs grows, and as newer molecules in the development pipeline continue to progress, interest related to these drugs continues to grow. This article describes a person-centered approach, using the bio-psychosocial model of health, to help individualized decision making related to choice of GLP1RA. It utilizes an evidence-based approach to discuss various biomedical and psychosocial factors which may influence choice of GLP1RA.

Incretin treatment and risk of pancreatitis in patients with type 2 diabetes mellitus: systematic review and meta-analysis of randomised and non-randomised studies

OBJECTIVE

To investigate the risk of pancreatitis associated with the use of incretin-based treatments in patients with type 2 diabetes mellitus.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

Medline, Embase, the Cochrane Central Register of Controlled Trials (CENTRAL), and ClinicalTrials.gov.

ELIGIBILITY CRITERIA

Randomised and non-randomised controlled clinical trials, prospective or retrospective cohort studies, and case-control studies of treatment with glucagon-like peptide-1 (GLP-1) receptor agonists or dipeptidyl peptidase-4 (DPP-4) inhibitors in adults with type 2 diabetes mellitus compared with placebo, lifestyle modification, or active anti-diabetic drugs.

DATA COLLECTION AND ANALYSIS

Pairs of trained reviewers independently screened for eligible studies, assessed risk of bias, and extracted data. A modified Cochrane tool for randomised controlled trials and a modified version of the Newcastle-Ottawa scale for observational studies were used to assess bias. We pooled data from randomised controlled trials using Peto odds ratios, and conducted four prespecified subgroup analyses and a post hoc subgroup analysis. Because of variation in outcome measures and forms of data, we describe the results of observational studies without a pooled analysis.

RESULTS

60 studies (n=353,639), consisting of 55 randomised controlled trials (n=33,350) and five observational studies (three retrospective cohort studies, and two case-control studies; n=320,289) were included. Pooled estimates of 55 randomised controlled trials (at low or moderate risk of bias involving 37 pancreatitis events, raw event rate 0.11%) did not suggest an increased risk of pancreatitis with incretins versus control (odds ratio 1.11, 95% confidence interval 0.57 to 2.17). Estimates by type of incretin suggested similar results (1.05 (0.37 to 2.94) for GLP-1 agonists v control; 1.06 (0.46 to 2.45) for DPP-4 inhibitors v control). Analyses according to the type of control, mode, duration of treatment, and individual incretin agents suggested no differential effect by subgroups, and sensitivity analyses by alternative statistical modelling and effect measures did not show important differences in effect estimates. Three retrospective cohort studies (moderate to high risk of bias, involving 1466 pancreatitis events, raw event rate 0.47%) also did not suggest an increased risk of pancreatitis associated with either exenatide (adjusted odds ratios 0.93 (0.63 to 1.36) in one study and 0.9 (0.6 to 1.5) in another) or sitagliptin (adjusted hazard ratio 1.0, 0.7 to 1.3); a case-control study at moderate risk of bias (1003 cases, 4012 controls) also suggested no significant association (adjusted odds ratio 0.98, 0.69 to 1.38). Another case-control study (1269 cases, 1269 controls) at moderate risk of bias, however, suggested that the use of either exenatide or sitagliptin was associated with significantly increased odds of acute pancreatitis (use within two years v no use, adjusted odds ratio 2.07, 1.36 to 3.13).

CONCLUSIONS

The available evidence suggests that the incidence of pancreatitis among patients using incretins is low and that the drugs do not increase the risk of pancreatitis. Current evidence, however, is not definitive, and more carefully designed and conducted observational studies are warranted to definitively establish the extent, if any, of increased risk.

Options for prandial glucose management in type 2 diabetes patients using basal insulin: addition of a short-acting GLP-1 analogue versus progression to basal-bolus therapy

Integrating patient-centered diabetes care and algorithmic medicine poses particular challenges when optimized basal insulin fails to maintain glycaemic control in patients with type 2 diabetes. Multiple entwined physiological, psychosocial and systems barriers to insulin adherence are not easily studied and are not adequately considered in most treatment algorithms. Moreover, the limited number of alternatives to add-on prandial insulin therapy has hindered shared decision-making, a central feature of patient-centered care. This article considers how the addition of a glucagon-like peptide 1 (GLP-1) analogue to basal insulin may provide new opportunities at this stage of treatment, especially for patients concerned about weight gain and risk of hypoglycaemia. A flexible framework for patient-clinician discussions is presented to encourage development of decision-support tools applicable to both specialty and primary care practice.

(Poly)peptide-based therapy for diabetes mellitus: insulins versus incretins

Insulin therapy remains the standard of care for achieving and maintaining adequate glycemic control, especially in hospitalized patients with critical and noncritical illnesses. Insulin therapy is more effective against elevated fasting glycaemia but less in the reduction of postprandial hyperglycaemia. It is associated with a high incidence of hypoglycemia and weight gain. Contrary, GLP-1 mimetic therapy improves postprandial glycaemia without the hypoglycaemia and weight gain associated with aggressive insulin therapy. Moreover, it has the potential to reduce cardiovascular related morbidity. However, its increased immunogenicity and severe gastrointestinal adverse effects present a huge burden on patients. Thus, a right combination of basal insulin which has lowering effect on fasting plasma glucose and GLP-1 mimetic with its lowering effect on postprandial plasma glucose with minimal gastrointestinal adverse effects, seems the right therapy choice from a clinical point of view for some diabetic patients. In this article, we discuss the pros and cons of the use of insulin analogues and GLP-1 mimetics that are associated with the treatment of type 2 diabetes.

Effect of GLP-1 mimetics on blood pressure and relationship to weight loss and glycemia lowering: results of a systematic meta-analysis and meta-regression

BACKGROUND

Incretin therapies such as glucagon-like peptide 1 (GLP-1) agonists are commonly used for the treatment of type 2 diabetes mellitus. GLP-1 mimetics, besides improving glycemic control, have been shown to influence multiple pathways regulating blood pressure (BP). We investigated the GLP-1 analogs effects on BP from published randomized studies using a meta-analytic approach.

METHODS

Thirty-three trials (12,469 patients) that assessed the efficacy of GLP-1 analogs on glycemic control (HbA1C) over 12-56 weeks that met additional criteria, including the availability of standardized sitting BP assessment and weight parameters, were identified. Comparator therapy included oral antiglycemic drugs or placebo. The weighted mean difference (WMD) in systolic BP (SBP) change was calculated using a random-effects model after performing a test for heterogeneity.

RESULTS

Forty-one percent of patients were treated with liraglutide (0.3-3mg once daily), whereas 59% were treated with exenatide (5-10 µg twice daily or 2mg weekly). GLP-1 treatment achieved a greater SBP reduction than comparator therapy (WMD = 2.22mm Hg; 95% confidence interval (CI) = -2.97 to -1.47). In the pooled analysis, GLP-1 had beneficial effects on weight loss (WMD = -2.56kg; 95% CI = -3.12 to -2.00), HbA1c reduction (WMD = -0.41%; 95% CI = -0.78 to -0.04) but was associated with a heart rate increase (WMD = 1.30 bpm; 95% CI = 0.26-2.33). In a separate meta-regression analysis, the degree of SBP change was not related to baseline BP, weight loss, or improvement in HbA1C.

CONCLUSIONS

This meta-analysis provides evidence that GLP-1 analogs reduce sitting SBP. These findings may support potentially favorable long-term cardiovascular outcomes.

Monotherapy with the once weekly GLP-1 receptor agonist dulaglutide for 12 weeks in Japanese patients with type 2 diabetes: dose-dependent effects on glycaemic control in a randomised, double-blind, placebo-controlled study

The aim of this study was to evaluate the dose-dependent effect of dulaglutide, a glucagon-like peptide-1 receptor agonist, on glycaemic control in Japanese patients with type 2 diabetes mellitus who were treated with diet/exercise or oral antidiabetic drug monotherapy. In this randomised, double-blind, placebo-controlled, parallel-group, 12-week study, patients received once weekly subcutaneous dulaglutide doses of 0.25, 0.5, or 0.75 mg (DU 0.25, DU 0.5, and DU 0.75, respectively) or placebo (n=36, 37, 35, and 37, respectively). The primary measure was change from baseline in glycated haemoglobin (HbA1c; %) at 12 weeks. Continuous variables were analysed using a mixed-effects model for repeated measures. Significant dose-dependent reductions in HbA1c were observed (least squares mean difference versus placebo [95% confidence interval]): DU 0.25=-0.72% (-0.95, -0.48), DU 0.5=-0.97% (-1.20, -0.73), and DU 0.75=-1.17% (-1.41, -0.93); p<0.001. Significant improvements in plasma glucose (PG), both fasting and average 7-point self-monitored blood glucose, were also observed with dulaglutide versus placebo (p<0.001). Dulaglutide was well-tolerated. Gastrointestinal adverse events (AEs) were more common in dulaglutide-treated patients, with nausea the most frequent (8 [5.5%]). Few dulaglutide-treated patients discontinued due to AEs (4 [3.7%]), and no serious AEs related to study medication occurred. Three patients (DU 0.5=1 and DU 0.75=2) reported asymptomatic hypoglycaemia (PG ≤70 mg/dL). The observed dose-dependent reduction in HbA1c and acceptable safety profile support further clinical development of dulaglutide for treatment of type 2 diabetes mellitus in Japan.

Clinical application of glucagon-like Peptide 1 receptor agonists for the treatment of type 2 diabetes mellitus

Glucagon-like peptide 1 (GLP-1) is secreted from enteroendocrine L-cells in response to oral nutrient intake and elicits glucose-stimulated insulin secretion while suppressing glucagon secretion. It also slows gastric emptying, which contributes to decreased postprandial glycemic excursions. In the 1990s, chronic subcutaneous infusion of GLP-1 was found to lower blood glucose levels in patients with type 2 diabetes. However, GLP-1's very short half-life, arising from cleavage by the enzyme dipeptidyl peptidase 4 (DPP-4) and glomerular filtration by the kidneys, presented challenges for clinical use. Hence, DPP-4 inhibitors were developed, as well as several GLP-1 analogs engineered to circumvent DPP-4-mediated breakdown and/or rapid renal elimination. Three categories of GLP-1 analogs, are being developed and/or are in clinical use: short-acting, long-acting, and prolonged-acting GLP-1 analogs. Each class has different plasma half-lives, molecular size, and homology to native GLP-1, and consequently different characteristic effects on glucose metabolism. In this article, we review current clinical data derived from each class of GLP-1 analogs, and consider the clinical effects reported for each category in recent head to head comparison studies. Given the relatively brief clinical history of these compounds, we also highlight several important efficacy and safety issues which will require further investigation.

Optimizing glycemic control: lixisenatide and basal insulin in combination therapy for the treatment of Type 2 diabetes mellitus

Despite availability of new treatments for patients with Type 2 diabetes mellitus (T2DM), optimal management of glycemic control remains challenging. Treatment with basal insulin can improve HbA1c, but may not be sufficient to control postprandial plasma glucose (PPG) levels. Both fasting plasma glucose (FPG) and PPG levels contribute to overall glycemic control. In patients with moderate hyperglycemia, PPG excursions have a greater contribution to overall hyperglycemia, with this contribution being greatest when HbA1c is approximately 7-8% [1] . Glucagon-like peptide-1 receptor agonists (GLP-1RAs) have been designed to restore and maintain GLP-1 levels and attenuate PPG excursions. GLP-1RAs that predominantly affect PPG may complement the FPG lowering provided by basal insulin, possibly improving overall glycemic control without additional weight gain and with limited incidence of hypoglycemia. Lixisenatide as an add-on to basal insulin lowers PPG levels, improves HbA1c control and has a beneficial effect on weight in T2DM patients.

Once-weekly exenatide versus once- or twice-daily insulin detemir: randomized, open-label, clinical trial of efficacy and safety in patients with type 2 diabetes treated with metformin alone or in combination with sulfonylureas

OBJECTIVE

This multicenter, open-label, parallel-arm study compared the efficacy and safety of exenatide once weekly (EQW) with titrated insulin detemir in patients with type 2 diabetes inadequately controlled with metformin (with or without sulfonylureas).

RESEARCH DESIGN AND METHODS

Patients were randomized to EQW (2 mg) or detemir (once or twice daily, titrated to achieve fasting plasma glucose ≤5.5 mmol/L) for 26 weeks. The primary outcome was proportion of patients achieving A1C ≤7.0% and weight loss ≥1.0 kg at end point, analyzed by means of logistic regression. Secondary outcomes included measures of glycemic control, cardiovascular risk factors, and safety and tolerability.

RESULTS

Of 216 patients (intent-to-treat population), 111 received EQW and 105 received detemir. Overall, 44.1% (95% CI, 34.7-53.9) of EQW-treated patients compared with 11.4% (6.0-19.1) of detemir-treated patients achieved the primary outcome (P < 0.0001). Treatment with EQW resulted in significantly greater reductions than detemir in A1C (least-square mean ± SE, -1.30 ± 0.08% vs. -0.88 ± 0.08%; P < 0.0001) and weight (-2.7 ± 0.3 kg vs. +0.8 ± 0.4 kg; P < 0.0001). Gastrointestinal-related and injection site-related adverse events occurred more frequently with EQW than with detemir. There was no major hypoglycemia in either group. Five (6%) patients in the EQW group and six (7%) patients in the detemir group experienced minor hypoglycemia; only one event occurred without concomitant sulfonylureas (detemir group).

CONCLUSIONS

Treatment with EQW resulted in a significantly greater proportion of patients achieving target A1C and weight loss than treatment with detemir, with a low risk of hypoglycemia. These results suggest that EQW is a viable alternative to insulin detemir treatment in patients with type 2 diabetes with inadequate glycemic control using oral antidiabetes drugs.

Longer acting GLP-1 receptor agonists and the potential for improved cardiovascular outcomes: a review of current literature

With the rapidly rising incidence of Type 2 diabetes and an increasing variety of medications available for treatment, choosing the ideal regimen for patients can be challenging. Longer-acting glucagon-like peptide-1 (GLP-1) receptor agonists and devices have been recently developed and include once-weekly exenatide, dulaglutide, albiglutide, semaglutide and miniosmotic pump ITCA650. Some of the attractive qualities of the GLP-1 receptor agonist class include its association with weightloss and potential for cardiovascular benefits. The longer-acting forms have been shown in several studies to produce equal or greater reduction in A1c and weight compared with the standard twice-daily formulation of exenatide. They also result in lower reported incidence of nausea, in the setting of a less frequent injection schedule that would be desirable to many diabetic patients. There are emerging data to suggest patients treated with longer-acting GLP-1 receptor agonists have improved cardiac parameters, some of which are independent of weight and A1c reductions.

Impact of GLP-1 receptor agonists on major gastrointestinal disorders for type 2 diabetes mellitus: a mixed treatment comparison meta-analysis

AIM

We aimed to integrate evidence from all randomized controlled trials (RCTs) and assess the impact of different doses of exenatide or liraglutide on major gastrointestinal adverse events (GIAEs) in type 2 diabetes (T2DM).

METHODS

RCTs evaluating different doses of exenatide and liraglutide against placebo or an active comparator with treatment duration ≥4 weeks were searched and reviewed. A total of 35, 32 and 28 RCTs met the selection criteria evaluated for nausea, vomiting, and diarrhea, respectively. Pairwise random-effects meta-analyses and mixed treatment comparisons (MTC) of all RCTs were performed.

RESULTS

All GLP-1 dose groups significantly increased the probability of nausea, vomiting and diarrhea relative to placebo and conventional treatment. MTC meta-analysis showed that there was 99.2% and 85.0% probability, respectively, that people with exenatide 10 μg twice daily (EX10BID) was more vulnerable to nausea and vomiting than those with other treatments. There was a 78.90% probability that liraglutide 1.2 mg once daily (LIR1.2) has a higher risk of diarrhea than other groups. A dose-dependent relationship of exenatide and liraglutide on GIAEs was observed.

CONCLUSIONS

Our MTC meta-analysis suggests that patients should be warned about these GIAEs in early stage of treatment by GLP-1s, especially by EX10BID and LIR1.2, to promote treatment compliance.

GLP-1 receptor agonists for individualized treatment of type 2 diabetes mellitus

In healthy humans, the incretin glucagon-like peptide 1 (GLP-1) is secreted after eating and lowers glucose concentrations by augmenting insulin secretion and suppressing glucagon release. Additional effects of GLP-1 include retardation of gastric emptying, suppression of appetite and, potentially, inhibition of β-cell apoptosis. Native GLP-1 is degraded within ~2-3 min in the circulation; various GLP-1 receptor agonists have, therefore, been developed to provide prolonged in vivo actions. These GLP-1 receptor agonists can be categorized as either short-acting compounds, which provide short-lived receptor activation (such as exenatide and lixisenatide) or as long-acting compounds (for example albiglutide, dulaglutide, exenatide long-acting release, and liraglutide), which activate the GLP-1 receptor continuously at their recommended dose. The pharmacokinetic differences between these drugs lead to important differences in their pharmacodynamic profiles. The short-acting GLP-1 receptor agonists primarily lower postprandial blood glucose levels through inhibition of gastric emptying, whereas the long-acting compounds have a stronger effect on fasting glucose levels, which is mediated predominantly through their insulinotropic and glucagonostatic actions. The adverse effect profiles of these compounds also differ. The individual properties of the various GLP-1 receptor agonists might enable incretin-based treatment of type 2 diabetes mellitus to be tailored to the needs of each patient.

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.

Monotherapy with the once-weekly GLP-1 analogue dulaglutide for 12 weeks in patients with Type 2 diabetes: dose-dependent effects on glycaemic control in a randomized, double-blind, placebo-controlled study

AIMS

Evaluate dose-dependent effects of once-weekly dulaglutide, a glucagon-like peptide-1 analogue, on glycaemic control in patients with Type 2 diabetes treated with lifestyle measures with or without previous metformin.

METHODS

This 12-week, double-blind, placebo-controlled, dose-response trial randomized 167 patients who were anti-hyperglycaemic medication-naïve or had discontinued metformin monotherapy [mean baseline HbA(1c) 59 ± 8 to 61 ± 8 mmol/mol (7.6 ± 0.7 to 7.8 ± 0.8%)] to once-weekly injections of placebo or dulaglutide (0.1, 0.5, 1.0 or 1.5 mg).

RESULTS

A significant dose-dependent reduction in HbA(1c) (least squares mean ± SE) was observed across doses (P < 0.001). HbA(1c) reductions in the 0.5, 1.0 and 1.5 mg dulaglutide groups were greater than in the placebo group [-10 ± 1, -11 ± 1 and -11 ± 1 vs. 0 ± 1 mmol/mol (-0.9 ± 0.1, -1.0 ± 0.1 and -1.0 ± 0.1 vs. 0.0 ± 0.1%), respectively, all P < 0.001]. Dose-dependent reductions in fasting plasma glucose were also observed [least squares mean difference (95% CI) ranging from -0.43 (-1.06 to 0.19) mmol/l for dulaglutide 0.1 mg to -1.87 (-2.56 to -1.19) mmol/l for dulaglutide 1.5 mg, P < 0.001]. Dose-dependent weight loss was demonstrated across doses (P = 0.009), but none of the groups were different from placebo. The most common adverse events were nausea and diarrhoea.

CONCLUSIONS

The observed dulaglutide dose-dependent reduction in HbA(1c) and its acceptable safety profile support further clinical development for treatment of Type 2 diabetes.

GLP-1 based therapies: differential effects on fasting and postprandial glucose

Glucagon-like peptide-1 (GLP-1), a gut-derived hormone secreted in response to nutrients, has several glucose and weight regulating actions including enhancement of glucose-stimulated insulin secretion, suppression of glucagon secretion, slowing of gastric emptying and reduction in food intake. Because of these multiple effects, the GLP-1 receptor system has become an attractive target for type 2 diabetes therapies. However, GLP-1 has significant limitations as a therapeutic due to its rapid degradation (plasma half-life of 1-2 min) by dipeptidyl peptidase-4 (DPP-4). Two main classes of GLP-1-mediated therapies are now in use: DPP-4 inhibitors that reduce the degradation of GLP-1 and DPP-4-resistant GLP-1 receptor (GLP-1R) agonists. The GLP-1R agonists can be further divided into short- and long-acting formulations which have differential effects on their mechanisms of action, ultimately resulting in differential effects on their fasting and postprandial glucose lowering potential. This review summarizes the similarities and differences among DPP-4 inhibitors, short-acting GLP-1R agonists and long-acting GLP-1R agonists. We propose that these different GLP-1-mediated therapies are all necessary tools for the treatment of type 2 diabetes and that the choice of which one to use should depend on the specific needs of the patient. This is analogous to the current use of modern insulins, as short-, intermediate- and long-acting versions are all used to optimize the 24-h plasma glucose profile as needed. Given that GLP-1-mediated therapies have advantages over insulins in terms of hypoglycaemic risk and weight gain, optimized use of these compounds could represent a significant paradigm shift for the treatment of type 2 diabetes.

Glucagon-like peptide analogues for type 2 diabetes mellitus

BACKGROUND

Glucagon-like peptide analogues are a new class of drugs used in the treatment of type 2 diabetes that mimic the endogenous hormone glucagon-like peptide 1 (GLP-1). GLP-1 is an incretin, a gastrointestinal hormone that is released into the circulation in response to ingested nutrients. GLP-1 regulates glucose levels by stimulating glucose-dependent insulin secretion and biosynthesis, and by suppressing glucagon secretion, delayed gastric emptying and promoting satiety.

OBJECTIVES

To assess the effects of glucagon-like peptide analogues in patients with type 2 diabetes mellitus.

SEARCH STRATEGY

Studies were obtained from electronic searches of The Cochrane Library (last search issue 1, 2011), MEDLINE (last search March 2011), EMBASE (last search March 2011), Web of Science (last search March 2011) and databases of ongoing trials.

SELECTION CRITERIA

Studies were included if they were randomised controlled trials of a minimum duration of eight weeks comparing a GLP-1 analogue with placebo, insulin, an oral anti-diabetic agent, or another GLP-1 analogue in people with type 2 diabetes.

DATA COLLECTION AND ANALYSIS

Data extraction and quality assessment of studies were done by one reviewer and checked by a second. Data were analysed by type of GLP-1 agonist and comparison treatment. Where appropriate, data were summarised in a meta-analysis (mean differences and risk ratios summarised using a random-effects model).

MAIN RESULTS

Seventeen randomised controlled trials including relevant analyses for 6899 participants were included in the analysis. Studies were mostly of short duration, usually 26 weeks.In comparison with placebo, all GLP-1 agonists reduced glycosylated haemoglobin A1c (HbA1c) levels by about 1%. Exenatide 2 mg once weekly and liraglutide 1.8 mg reduced it by 0.20% and 0.24% respectively more than insulin glargine. Exenatide 2 mg once weekly reduced HbA1c more than exenatide 10 μg twice daily, sitagliptin and pioglitazone. Liraglutide 1.8 mg reduced HbA1c by 0.33% more than exenatide 10 μg twice daily. Liraglutide led to similar improvements in HbA1c compared to sulphonylureas but reduced it more than sitagliptin and rosiglitazone.Both exenatide and liraglutide led to greater weight loss than most active comparators, including in participants not experiencing nausea. Hypoglycaemia occurred more frequently in participants taking concomitant sulphonylurea. GLP-1 agonists caused gastrointestinal adverse effects, mainly nausea. These adverse events were strongest at the beginning and then subsided. Beta-cell function was improved with GLP-1 agonists but the effect did not persist after cessation of treatment.None of the studies was long enough to assess long-term positive or negative effects.

AUTHORS' CONCLUSIONS

GLP-1 agonists are effective in improving glycaemic control.

A 5-week study of the pharmacokinetics and pharmacodynamics of LY2189265, a novel, long-acting glucagon-like peptide-1 analogue, in patients with type 2 diabetes

AIM

To investigate the safety, tolerability, pharmacokinetics and pharmacodynamics of LY2189265 (LY), a novel, long-acting glucagen-like peptide-1 analogue, administered once weekly to subjects with type 2 diabetes.

METHODS

This was a placebo-controlled, parallel-group, subject- and investigator-blind study of LY in subjects (N = 43) with type 2 diabetes mellitus controlled with diet and exercise alone or with a single oral antidiabetic medication. Subjects taking metformin or thiazolidinediones continued on their therapy. Subjects receiving sulfonylurea, acarbose, repaglinide or nateglinide were switched to metformin prior to enrollment. Subjects received five once-weekly doses of 0.05, 0.3, 1, 3, 5 or 8 mg. Effects on glucose, insulin and C-peptide concentrations were determined during fasting and following standard test meals. The pharmacokinetics of LY and its effects on HBA1c, glucagon, body weight, gastric emptying and safety parameters were assessed.

RESULTS

Once-weekly administration of LY significantly reduced (p < 0.01) fasting plasma glucose, 2-h post-test meal postprandial glucose and area under the curve (AUC) of glucose after test meals at doses ≥1 mg. These effects were seen after the first dose and were sustained through the weekly dosing cycle. Most doses produced statistically significant increases in insulin and C-peptide AUC when normalized for glucose AUC. Statistically significant reductions in HBA1c were observed for all dose groups except 0.3 mg. The most commonly reported adverse effects (AEs) were nausea (35 events), headache (20 events), vomiting (18 events) and diarrhoea (8 events).

CONCLUSIONS

LY showed improvement in fasting and postprandial glycaemic parameters when administered once weekly in subjects with type 2 diabetes. The pharmacokinetics and safety profiles also support further investigation of this novel agent.