A placebo-controlled trial of exenatide twice-daily added to thiazolidinediones alone or in combination with metformin

Effect of combination pioglitazone with sodium-glucose cotransporter-2 inhibitors or glucagon-like peptide-1 receptor agonists on outcomes in type 2 diabetes: A systematic review, meta-analysis, and real-world study from an international federated database

AIMS

To evaluate the efficacy and cardiovascular outcomes of combination pioglitazone with either a glucagon-like peptide-1 receptor agonist (GLP-1RA) or a sodium-glucose cotransporter-2 (SGLT2) inhibitor in individuals with type 2 diabetes (T2D) by conducting a systematic review, meta-analysis, and analysis of a large international real-world database.

METHODS

We searched MEDLINE, SCOPUS and Web of Science to identify relevant articles for inclusion (PROSPERO [CRD: 42023483126]). Nineteen studies assessing pioglitazone + SGLT2 inhibitors or GLP-1RAs versus controls were identified, 16 of which were randomized controlled trials. Risk of bias was assessed using Cochrane-endorsed tools and quality of evidence was assessed using GRADE. We additionally performed a retrospective cohort study of all individuals aged 18 years or over with T2D, using the TriNetX platform. We included propensity-score-matched individuals who were treated for at least 1 year with pioglitazone and a GLP-1RA or pioglitazone and an SGLT2 inhibitor, compared against GLP-1RA and SGLT2 inhibitor monotherapy. Outcomes were all-cause mortality, heart failure, chronic kidney disease and composite stroke and transient ischaemic attack.

RESULTS

The average follow-up in the included studies ranged from 24 to 52 weeks. Combination of pioglitazone with a GLP-1RA reduced glycated haemoglobin (HbA1c) and weight greater than in controls: mean differences -1% (95% confidence interval [CI] -1.27, -0.74) and -1.19 kg (95% CI -1.80, -0.58), respectively. There was no statistically significant difference in systolic blood pressure (SBP) or mortality between groups: mean difference - 1.56 mmHg (95% CI -4.48, 1.35; p = 0.30) and relative risk (RR) 0.29 (95% CI 0.07-1.15; p = 0.08), respectively. Combination of pioglitazone with SGLT2 inhibitors reduced HbA1c, weight and SBP to a greater extent than control treatment: mean differences -0.48% (95% CI -0.67, -0.28), -2.3 kg (95% CI -2.72, -1.88) and -2.4 mmHg (95% CI -4.1, -0.7; p = 0.01), respectively. There was no statistically significant difference in mortality between groups (RR 1.81, 95% CI 0.30-10.97; p = 0.52). The included trials demonstrated a reduction in risk of heart failure with combination treatment. Similarly, from the real-world database (n = 25 230 identified), pioglitazone and SGLT2 inhibitor combination therapy was associated with reduced risk of heart failure compared to monotherapy alone (hazard ratio 0.50, 95% CI 0.38-0.65; p < 0.001).

CONCLUSION

Both our systematic review/meta-analysis and the real-world dataset show that combination of pioglitazone with either GLP-1RAs or SGLT2 inhibitors is associated with increased weight loss and reduced risk of heart failure compared with monotherapy.

Glucagon-like peptide-1 receptor agonists modestly reduced blood pressure among patients with and without diabetes mellitus: A meta-analysis and meta-regression

AIM

The cardiovascular benefits provided by glucagon-like peptide-1 receptor agonists (GLP-1RAs) extend beyond weight reduction and glycaemic control. One possible mechanism may relate to blood pressure (BP) reduction. We aim to quantify the BP-lowering effects of GLP1-RAs.

METHODS

A comprehensive database search for placebo-controlled randomized controlled trials on GLP-1RA treatment was conducted until December 2023. Data extraction and quality assessment were carried out, employing a robust statistical analysis using a random effects model to determine outcomes with a mean difference (MD) in mmHg and 95% confidence intervals (CIs). The primary endpoint was the mean difference in systolic BP (SBP) and diastolic BP. Subgroup analyses and meta-regressions were done to account for covariates.

RESULTS

Compared with placebo, GLP-1RAs modestly reduced SBP [semaglutide: MD -3.40 (95% CI -4.22 to -2.59, p < .001); liraglutide: MD -2.61 (95% CI -3.48 to -1.74, p < .001); dulaglutide: MD -1.46 (95% CI -2.20 to -0.72, p < .001); and exenatide: MD -3.36 (95% CI -3.63 to -3.10, p < .001)]. This benefit consistently increased with longer treatment durations. Diastolic BP reduction was only significant in the exenatide group [MD -0.94 (95% CI -1.78 to -0.1), p = .03]. Among semaglutide cohorts, mean changes in glycated haemoglobin and mean changes in body mass index were directly associated with SBP reduction.

CONCLUSION

Patients on GLP-1RA experienced modest SBP lowering compared with placebo. This observed effect was associated with weight/body mass index reduction and better glycaemic control, which suggests that BP-lowering is an indirect effect of GLP-1RA and unlikely to be responsible for the benefits.

GLP-1RAs caused gastrointestinal adverse reactions of drug withdrawal: a system review and network meta-analysis

Background

Glucagon-like peptide-1 receptor agonists (GLP-1RAs) significantly reduce postprandial blood glucose, inhibit appetite, and delay gastrointestinal emptying. However, it is controversial that some patients are intolerant to GLP-1RAs.

Methods

PubMed, Embase, Web of Science, and Cochrane Library were searched for randomized controlled trials (RCTs) using GLP-1RAs with documented withdrawal due to gastrointestinal adverse reactions (GI AEs) from their inception to September 28, 2022. After extracting the information incorporated into the studies, a random-effects network meta-analysis was performed within a frequentist framework.

Results

64 RCTs were finally enrolled, which included six major categories of the GLP-1RA. The sample size of the GLP-1RAs treatment group was 16,783 cases. The risk of intolerable gastrointestinal adverse reactions of Liraglutide and Semaglutide was higher than that of Dulaglutide. Meanwhile, the higher the dose of the same GLP-1RA preparation, the more likely to cause these adverse reactions. These intolerable GI AEs were not significantly related to drug homology or formulations and may be related to the degree of suppression of the appetite center.

Conclusion

Dulaglutide caused the lowest intolerable GI AEs, while Liraglutide and Semaglutide were the highest. For Semaglutide, the higher the dose, the more likely it is to drive GI AEs. Meanwhile, the risk of these GI AEs is independent of the different formulations of the drug. All these findings can effectively guide individualized treatment.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42022359346, identifier CRD42022359346.

Association of Glucagon-like Peptide 1 Analogs and Agonists Administered for Obesity with Weight Loss and Adverse Events: A Systematic Review and Network Meta-analysis

BACKGROUND

Comparative effectiveness of 7 glucagon-like peptide 1 (GLP-1) agents on weight loss (WL) in obesity remains unknown.

METHODS

We performed a systematic review, network meta-analysis (NMA) utilizing the following data sources: MEDLINE, EMBASE, Scopus, Cochrane Central and clinical trial registries, from inception to March 2, 2021. The prespecified criteria for study inclusion were randomized clinical trials (RCTs) of ≥12 weeks' duration. The data appraisal and extraction were performed by two investigators independently, using the published reports. The main outcomes and statistical methods were weight loss over placebo (WLOP) and adverse events (AEs) among GLP-1 agents using random-effects NMA (frequentist approach); relative ranking using surface under the cumulative ranking (SUCRA) method and certainty of evidence using grading of recommendations, assessment, development and evaluations (GRADE).

FINDINGS

64 RCTs (from 2004 to 2021) included 27018 patients (median of age, 55.1 years old; 57.4% women; baseline weight 94.8kg and BMI 33.0kg/m²; trial duration 26 weeks). Direct meta-analysis showed significant WLOP with: -1.44kg (95% CI, -2.14 to -0.74) with dulaglutide ≥1.5 mg; -1.82kg (-2.42 to -1.23) with exenatide immediate release (IR); -2.20kg (-4.31 to -0.08) with exenatide extended release (ER); -3.20kg (-6.53 to 0.15) with efpeglenatide; -2.72kg (-3.35 to -2.09) with liraglutide ≤1.8mg; -4.49kg (-5.26 to -3.72) with liraglutide >1.8mg; -0.62kg (-1.22 to -0.02) with lixisenatide; -4.33kg (-5.71 to -3.00) with semaglutide SQ <2.4mg; -9.88kg (-13.17 to -6.59) with semaglutide SQ 2.4mg; -2.73kg (-4.81 to -0.65) with semaglutide oral; and -1.71kg (-2.64 to -0.78) with taspoglutide. Highest WLOP were with semaglutide SQ 2.4mg and <2.4mg, and liraglutide >1.8mg (SUCRAs 100, 86.1, 82.8 respectively). Highest SUCRAs for discontinuation due to AEs were with taspoglutide and liraglutide >1.8mg. Risk of bias was high or unclear for random sequence generation (29.7%), allocation concealment (26.6%), and incomplete outcome data (26.6%). Heterogeneity (I² >50%) in WL and AEs reflected magnitude, not direction of effect.

Age, sex, disease severity, and disease duration difference in placebo response: implications from a meta-analysis of diabetes mellitus

BACKGROUND

The placebo response in patients with diabetes mellitus is very common. A systematic evaluation needs to be updated with the current evidence about the placebo response in diabetes mellitus and the associated factors in clinical trials of anti-diabetic medicine.

METHODS

Literature research was conducted in Medline, Embase, the Cochrane Central Register of Controlled Trials, and ClinicalTrials.gov for studies published between the date of inception and June 2019. Randomized placebo-controlled trials conducted in type 1and type 2 diabetes mellitus (T1DM/T2DM) were included. Random-effects model and meta-regression analysis were accordingly used. This meta-analysis was registered in PROSPERO as CRD42014009373.

RESULTS

Significantly weight elevation (effect size (ES) = 0.33 kg, 95% CI, 0.03 to 0.61 kg) was observed in patients with placebo treatments in T1DM subgroup while significantly HbA1c reduction (ES = - 0.12%, 95% CI, - 0.16 to - 0.07%) and weight reduction (ES = - 0.40 kg, 95% CI, - 0.50 to - 0.29 kg) were observed in patients with placebo treatments in T2DM subgroup. Greater HbA1c reduction was observed in patients with injectable placebo treatments (ES = - 0.22%, 95% CI, - 0.32 to - 0.11%) versus oral types (ES = - 0.09%, 95% CI, - 0.14 to - 0.04%) in T2DM (P = 0.03). Older age (β = - 0.01, 95% CI, - 0.02 to - 0.01, P < 0.01) and longer diabetes duration (β = - 0.02, 95% CI, - 0.03 to - 0.21 × 10^-2, P = 0.03) was significantly associated with more HbA1c reduction by placebo in T1DM. However, younger age (β = 0.02, 95% CI, 0.01 to 0.03, P = 0.01), lower male percentage (β = 0.01, 95% CI, 0.22 × 10^-2, 0.01, P < 0.01), higher baseline BMI (β = - 0.02, 95% CI, - 0.04 to - 0.26 × 10^-2, P = 0.02), and higher baseline HbA1c (β = - 0.09, 95% CI, - 0.16 to - 0.01, P = 0.02) were significantly associated with more HbA1c reduction by placebo in T2DM. Shorter diabetes duration (β = 0.06, 95% CI, 0.06 to 0.10, P < 0.01) was significantly associated with more weight reduction by placebo in T2DM. However, the associations between baseline BMI, baseline HbA1c, and placebo response were insignificant after the adjusted analyses.

CONCLUSION

The placebo response in diabetes mellitus was systematically outlined. Age, sex, disease severity (indirectly reflected by baseline BMI and baseline HbA1c), and disease duration were associated with placebo response in diabetes mellitus. The association between baseline BMI, baseline HbA1c, and placebo response may be the result of regression to the mean.

Effect of Hemoglobin A1c Reduction or Weight Reduction on Blood Pressure in Glucagon-Like Peptide-1 Receptor Agonist and Sodium-Glucose Cotransporter-2 Inhibitor Treatment in Type 2 Diabetes Mellitus: A Meta-Analysis

Background Glucagon-like peptide-1 receptor agonists (GLP-1RAs) and sodium-glucose cotransporter-2 inhibitors (SGLT2is) have shown their beneficial effects on cardiovascular outcomes and multiple cardiovascular risk factors, including hypertension. However, the mechanism of blood pressure (BP)-lowering effects of these agents has not been elucidated. This study aims to evaluate the effect of hemoglobin A1c reduction or body weight reduction with GLP-1RA treatment and SGLT2i treatment on BP changes in patients with type 2 diabetes mellitus. Methods and Results Studies were identified by a search of MEDLINE, EMBASE, and the Cochrane Central Register until June 2019. Meta-regression analysis was performed to evaluate the association between hemoglobin A1c reduction or body weight reduction and changes of BP. A total of 184 trials were included. Both GLP-1RA and SGLT2i led to significant reductions in systolic BP (weighted mean difference, -2.856 and -4.331 mm Hg, respectively; P<0.001 for both) and diastolic BP (weighted mean difference, -0.898 and -2.279 mm Hg, respectively; P<0.001 for both). For both drug classes, hemoglobin A1c reduction was not independently associated with systolic BP reduction or diastolic BP reduction. In GLP-1RA treatment, weight reduction was positively associated with systolic BP reduction and diastolic BP reduction (β=0.821 and β=0.287, respectively; P<0.001 for both). In SGLT2i treatment, weight loss was significantly associated with systolic BP reduction (β=0.820; P=0.001) but was not associated with diastolic BP reduction. Conclusions Treatment with GLP-1RA and SGLT2i led to significant reductions in BP in patients with type 2 diabetes mellitus. Weight reduction was significantly and independently associated with BP reductions in GLP-1RA treatment and SGLT2i treatment.

Orally Administered Semaglutide Versus GLP-1 RAs in Patients with Type 2 Diabetes Previously Receiving 1-2 Oral Antidiabetics: Systematic Review and Network Meta-Analysis

INTRODUCTION

Orally administered semaglutide is the first glucagon-like peptide 1 receptor agonist (GLP-1 RA) for oral administration. As head-to-head trials assessing orally administered semaglutide as an add-on to 1-2 oral antidiabetic drugs (OADs) vs other GLP-1 RAs are limited, a network meta-analysis (NMA) was performed to assess the relative efficacy and safety of orally administered semaglutide 14 mg once-daily (QD) vs injectable GLP-1 RAs in patients with type 2 diabetes inadequately controlled on 1-2 OADs.

METHODS

A systematic literature review was conducted to identify randomised controlled trials of GLP-1 RAs in patients inadequately controlled on 1-2 OADs. Data at 26 ± 4 weeks were extracted for efficacy and safety outcomes feasible for the NMA: change from baseline in glycated haemoglobin (HbA_1c), weight, HbA_1c target levels (< 7.0% and ≤ 6.5%), blood pressure, and any gastrointestinal adverse events specified in system organ class. Data were synthesised using NMA and a Bayesian framework.

RESULTS

In total, 27 studies were included in the analyses. Orally administered semaglutide 14 mg QD was associated with significantly greater reductions in HbA_1c vs most comparators, and numerically greater reductions vs semaglutide 0.5 mg once-weekly (QW), dulaglutide 1.5 mg QW and liraglutide 1.8 mg QD. HbA_1c reductions with semaglutide 1 mg QW were numerically greater than those with orally administered semaglutide 14 mg QD. Reductions in body weight for orally administered semaglutide 14 mg QD were significantly greater than all comparators except semaglutide QW (both doses). Orally administered semaglutide QD 14 mg was associated with statistically similar odds of experiencing gastrointestinal adverse events vs injectable GLP-1 RAs.

CONCLUSION

Orally administered semaglutide 14 mg QD as an add-on to 1-2 OADs is one of the most efficacious GLP-1 RAs for reducing HbA_1c and body weight at 26 ± 4 weeks. Orally administered semaglutide 14 mg QD is well tolerated, with a safety profile in line with the GLP-1 RA class.

FUNDING

Novo Nordisk.

Efficacy and safety of once daily liraglutide versus twice daily exenatide in type 2 diabetic patients in Qatar: an observational study

Objective

Compare efficacy and safety of liraglutide (1.8 mg subcutaneous once daily) and exenatide (10 mcg subcutaneous twice daily) in uncontrolled type 2 diabetes at 26 and 52 weeks.

Method

A retrospective observation study of uncontrolled type 2 diabetes patients who took liraglutide or exenatide in addition to their anti-diabetic medications. This study was conducted at Hamad Medical Corporation, the predominant public healthcare organization in Qatar. The primary outcome was the change in haemoglobin A1C (HbA1C) after 26 and 52 weeks.

Key finding

Two hundred and two patients were included in this study (liraglutide 98, exenatide 114). There was no significant HbA1C change observed between two groups at either 26 or 52 weeks (P = 0.23 and 0.40 respectively). However, more patients in the liraglutide group achieved HbA1C ≤7% at week 26. Liraglutide reduced the mean Fasting blood glucose (FBG) more than exenatide at week 26 and 52. Although both medications were associated with some benefits in other studied variables at a certain point (e.g. weight losses, blood pressure), neither of them were able to show a significant change from baseline. No patients in either group reported drug-related side effects (e.g. nausea and vomiting) or episodes of hypoglycaemia during the treatment period.

Conclusions

Exenatide and liraglutide resulted in similar glycaemic effects (HbA1C and fasting plasma glucose changes) in patients with type 2 diabetes who were sub-optimally controlled with other anti-diabetic therapy. However, this study supports the effectiveness of both medications for weight reduction at both endpoints. A prospective large-scale study is recommended to overcome the study limitations.

A Systematic Literature Review and Network Meta-Analysis Comparing Once-Weekly Semaglutide with Other GLP-1 Receptor Agonists in Patients with Type 2 Diabetes Previously Receiving 1-2 Oral Anti-Diabetic Drugs

INTRODUCTION

Once-weekly semaglutide is a new glucagon-like peptide-1 (GLP-1) analogue administered at a 1.0 or 0.5 mg dose. As head-to-head trials assessing once-weekly semaglutide as an add-on to 1-2 oral anti-diabetic drugs (OADs) vs other GLP-1 receptor agonists (GLP-1 RAs) are limited, a network meta-analysis (NMA) was performed. The objective was to assess the relative efficacy and safety of once-weekly semaglutide vs GLP-1 RAs in patients with type 2 diabetes (T2D) inadequately controlled on 1-2 OADs.

METHODS

A systematic literature review (SLR) was conducted in order to identify trials of GLP-1 RAs in patients inadequately controlled on 1-2 OADs. Data at 24 ± 4 weeks were extracted for efficacy and safety outcomes (feasible for analysis in a NMA), which included the key outcomes of change from baseline in glycated hemoglobin (HbA_1c), systolic blood pressure (SBP), and weight, as well as discontinuation due to adverse events (AEs). Data were synthesized using a NMA and a Bayesian framework.

RESULTS

In total, 26 studies were included across the base case analyses. Once-weekly semaglutide 1.0 mg was associated with significantly greater reductions in HbA_1c and weight vs all GLP-1 RA comparators. Once-weekly semaglutide 0.5 mg also achieved significantly greater reductions in HbA_1c and weight compared with the majority of other GLP-1 RAs. Both doses of once-weekly semaglutide were associated with similar odds of discontinuation due to AEs compared with other GLP-1 RAs.

CONCLUSION

Overall, once-weekly semaglutide 1.0 mg as an add-on to 1-2 OADs is the most efficacious GLP-1 RA in terms of the reduction of HbA_1c and weight from baseline after 6 months of treatment. In addition, the analysis suggests that once-weekly semaglutide is well tolerated and not associated with an increase in discontinuations due to AEs compared with other GLP-1 RAs.

FUNDING

Novo Nordisk.

Effects of exenatide twice daily, exenatide once weekly or insulin in patients with type 2 diabetes and baseline HbA1c ≥10.0%: Two pooled analyses including 20 randomised controlled trials

AIMS

Patients with advanced type 2 diabetes (T2D) and high glycated haemoglobin (HbA1c) values can be difficult to treat because of their severe metabolic disease. This pooled analysis examined the treatment effects of exenatide twice daily (BID), exenatide once weekly (QW) and insulin in patients with high baseline HbA1c (≥10.0%).

METHODS

This post hoc analysis used pooled data from 12 and 8 randomised controlled trials of exenatide BID and exenatide QW, respectively. Patients with T2D who completed at least 24 weeks of treatment with exenatide BID, exenatide QW or insulin (insulin glargine, insulin detemir or insulin aspart) were categorised by baseline HbA1c. Patients with HbA1c ≥10.0% were included in the analysis.

RESULTS

Both exenatide and insulin reduced HbA1c (mean ± SE reduction: -2.0% ± 0.2% [exenatide] and -2.1% ± 0.2% [insulin] in the exenatide BID studies, and -2.6% ± 0.1% [exenatide] and -2.1% ± 0.2% [insulin] in the exenatide QW studies; all P < .001). Body weight decreased with exenatide and increased with insulin. Systolic blood pressure decreased with exenatide QW. Insulin dose increased over the course of treatment. The most common adverse events with exenatide were gastrointestinal. Insulin was associated with some hypoglycaemia risk. Hypoglycaemia events occurred infrequently with exenatide when given without sulphonylureas.

CONCLUSIONS

For patients with high HbA1c, treatment with exenatide or insulin both improved glycaemic control. Given the associated weight loss and low risk of hypoglycaemia, exenatide may be a suitable alternative to treatment with insulin in certain patients with T2D and high HbA1c.

The Role of Glucagon-like Peptide-1 Receptor Agonists in the Treatment of Type 2 Diabetes

The role of GLP-1 agonists in the treatment of type 2 diabetes have been shown to be viable options for add-on therapy in diabetic patients, as well as potential monotherapy options. With six available GLP-1 agents, and new combination products in the pipeline, they are a promising drug class for type 2 diabetic patients, especially due to their extended dosing interval and potential weight loss benefits.

Efficacy and safety of glucagon-like peptide-1 receptor agonists in type 2 diabetes: A systematic review and mixed-treatment comparison analysis

AIMS

To compare efficacy and safety of glucagon-like peptide-1 receptor agonists (GLP-1RAs) in people with type 2 diabetes.

MATERIALS AND METHODS

We electronically searched, up to June 3, 2016, published randomized clinical trials lasting between 24 and 32 weeks that compared a GLP-1RA (albiglutide, dulaglutide, twice-daily exenatide and once-weekly exenatide, liraglutide, lixisenatide, semaglutide and taspoglutide) with placebo or another GLP-1RA. Data on cardiometabolic and safety outcomes were analysed using a mixed-treatment comparison meta-analysis.

RESULTS

A total of 34 trials (14 464 participants) met the inclusion criteria; no published data for semaglutide were available. Compared with placebo, all GLP-1RAs reduced glycated haemoglobin (HbA1c) and fasting plasma glucose (FPG) levels (reductions ranged from -0.55% and -0.73 mmol/L, respectively, for lixisenatide to -1.21% and -1.97 mmol/L, respectively, for dulaglutide). There were no differences within short-acting (twice-daily exenatide and lixisenatide) or long-acting (albiglutide, dulaglutide, once-weekly exenatide, liraglutide and taspoglutide) groups. Compared with twice-daily exenatide, dulaglutide treatment was associated with the greatest HbA1c and FPG reduction (0.51% and 1.04 mmol/L, respectively), followed by liraglutide (0.45% and 0.93 mmol/L, respectively) and once-weekly exenatide (0.38% and 0.85 mmol/L, respectively); similar reductions were found when these 3 agents were compared with lixisenatide. Compared with placebo, all GLP-1RAs except albiglutide reduced weight and increased the risk of hypoglycaemia and gastrointestinal side effects, and all agents except dulaglutide and taspoglutide reduced systolic blood pressure. When all GLP-1RAs were compared with each other, no clinically meaningful differences were observed in weight loss, blood pressure reduction or hypoglycaemia risk. Albiglutide had the lowest risk of nausea and diarrhoea and once-weekly exenatide the lowest risk of vomiting.

CONCLUSIONS

The RCTs in the present analysis show that all GLP-1RAs improve glycaemic control, reduce body weight and increase the risk of adverse gastrointestinal symptoms compared with placebo. Although there were no differences when short-acting agents were compared with each other or when long-acting agents were compared with each other, dulaglutide, liraglutide and once-weekly exenatide were superior to twice-daily exenatide and lixisenatide at lowering HbA1c and FPG levels. There were no differences in hypoglycaemia between these 3 agents, whilst once-weekly exenatide had the lowest risk of vomiting. These results, along with patient's preferences and individualized targets, should be considered when selecting a GLP-1RA.

Once-daily liraglutide (1.2 mg) compared with twice-daily exenatide (10 μg) in the treatment of type 2 diabetes patients: An indirect treatment comparison meta-analysis

BACKGROUND

Glucagon-like peptide-1 receptor agonists provide effective hyperglycemia management in patients with type 2 diabetes. In a randomized head-to-head trial, liraglutide 1.8 mg q.d. led to greater reductions in HbA1c than exenatide 10 μg b.i.d. There are no direct comparisons of liraglutide 1.2 mg q.d. and exenatide b.i.d.; therefore, in the present study, an indirect comparison and meta-analysis were undertaken.

METHODS

A systematic literature search was performed for randomized controlled trials of liraglutide 1.2 mg q.d. or exenatide b.i.d. with HbA1c as an outcome and ≥25 subjects. Key data were extracted and analyzed. A random-effects model was used to incorporate heterogeneity between studies.

RESULTS

Three liraglutide 1.2 mg q.d. (n = 1060) and 10 exenatide b.i.d. (n = 2609) placebo-controlled studies were identified, allowing indirect comparison with placebo as the common arm. Baseline characteristics were mean age ~55 years, disease duration ~7 years, HbA1c ~8%, and body mass index ~32 kg/m² . Compared with exenatide b.i.d., liraglutide 1.2 mg was associated with significantly greater reductions from baseline in HbA1c (-0.29%; 95% confidence interval [CI] -0.53, -0.05) and fasting plasma glucose (-0.92 mmol/L; 95% CI -1.43, -0.41), with shorter duration of nausea (3 vs 14 days; P = 0.002) and fewer withdrawals (odds ratio 0.34; 95% CI 0.22, 0.52). The incidence of adverse events (including nausea) and withdrawals because of adverse events were similar between treatments.

CONCLUSIONS

Liraglutide 1.2 mg provided a significantly greater reduction in HbA1c than exenatide 10 μg b.i.d. The significantly shorter duration of nausea with liraglutide than exenatide may be appreciated by patients.

The Use of Exenatide in Managing Markers of Cardiovascular Risk in Patients with Type 2 Diabetes: A Systematic Review

Objective: This review examines the use of exenatide twice daily in managing changes in markers of cardiovascular risk in patients with type 2 diabetes. Background: Type 2 diabetes is a progressive metabolic disorder, which results from defects in insulin secretion and/or insulin action leading to chronic hyperglycaemia and associated cardiovascular complications. Despite the use of diet, exercise, oral antihyperglycaemic agents and insulin, the progressive nature of the condition means that the levels of the preventive and treatment measures would have to be increased and/or new therapies have to be developed in order to address the long term impact of type 2 diabetes. The advent of exenatide, a glucagon-like peptide-1 receptor agonist provides a useful basis for managing type 2 diabetes and related cardiovascular complications without the side effects of regular diabetes therapies. However, exenatide twice daily is often used in combination with other therapies, although the mechanism of exenatide in managing diabetes and and associated cardiovascular risks and complications remain complex and still evolving. Method: A range of databases including EBSCOhost online research database were used to access articles based on PICO (Population, Interventions, Comparative Interventions, Outcomes) framework and Boolean operators. Results: Eleven randomised controlled studies which met the inclusion criteria were selected for this review. Nine of the eleven studies showed significant decrease in body weight among participants in the exenatide group compared with placebo or control group while the other two studies did not report statistically significant differences in body weight. In adition, all the studies showed statistically significant decrease in glycated haemoglobin (HbA1c) in the exenatide group compared to controls except in one study. In the present review, the seven studies, which looked at the effect of exenatide twice daily on lipid profile, did not find any significant difference between the exenatide group and the control group except for High density lipoprotein-cholesterol in two of the studies. However, statistically significant decrease was observed between exenatide group and controls with respect to blood pressure (systolic and/or diastolic) in these studies. Discussion: It would appear that exenatide is more effective in reducing body weight in patients with type 2 diabetes when used in combination with metformin than when used alone or in combination with thiazolidinedione. The findings of this review would suggest that exenatide twice daily may be useful in managing cardiovascular risks and complications by reducing body weight, HbA1c and blood pressure.

Triple therapy combinations for the treatment of type 2 diabetes - A network meta-analysis

AIM

To estimate and compare the results from all randomised trials of triple combinations of anti-diabetes therapies that reported the reduction of glycated haemoglobin (HbA1c) and associated effects on body weight and hypoglycaemia.

METHODS

PubMed and the Cochrane Library were searched for trials with at least one study arm on triple therapy and which reported the differences in mean change in HbA1c between two study arms. These were included in a network meta-analysis.

RESULTS

Altogether, 15,182 participants from 40 trials with treatment duration of 6-12months were included. Compared with none/placebo added to dual therapy, the addition of a drug therapy from six of eight drug classes to existing dual therapy resulted in significant additional mean reductions in HbA1c from -0.56% (-6.2mmol/mol; dipeptidyl peptidase 4 inhibitors) to -0.94% (-10.3mmol/mol; thiazolidinediones). Of the six drug classes, three were associated with less favourable weight change and two were associated with more favourable weight change when compared with none/placebo added to dual therapy. Furthermore, five drug classes were associated with greater odds of hypoglycaemia. Similar results were observed in analyses of studies with a 6month treatment duration and after excluding study arms that contained insulin.

CONCLUSIONS

Overall triple therapy combinations were similar in improving diabetes control although there were some differences in adverse effects. By balancing the risks and benefits of each therapy, the estimates of pairwise comparisons of triple therapies for HbA1c, body weight and hypoglycaemia provided in this study may further inform evidence based practice.

A genomic approach to therapeutic target validation identifies a glucose-lowering GLP1R variant protective for coronary heart disease

Regulatory authorities have indicated that new drugs to treat type 2 diabetes (T2D) should not be associated with an unacceptable increase in cardiovascular risk. Human genetics may be able to guide development of antidiabetic therapies by predicting cardiovascular and other health endpoints. We therefore investigated the association of variants in six genes that encode drug targets for obesity or T2D with a range of metabolic traits in up to 11,806 individuals by targeted exome sequencing and follow-up in 39,979 individuals by targeted genotyping, with additional in silico follow-up in consortia. We used these data to first compare associations of variants in genes encoding drug targets with the effects of pharmacological manipulation of those targets in clinical trials. We then tested the association of those variants with disease outcomes, including coronary heart disease, to predict cardiovascular safety of these agents. A low-frequency missense variant (Ala316Thr; rs10305492) in the gene encoding glucagon-like peptide-1 receptor (GLP1R), the target of GLP1R agonists, was associated with lower fasting glucose and T2D risk, consistent with GLP1R agonist therapies. The minor allele was also associated with protection against heart disease, thus providing evidence that GLP1R agonists are not likely to be associated with an unacceptable increase in cardiovascular risk. Our results provide an encouraging signal that these agents may be associated with benefit, a question currently being addressed in randomized controlled trials. Genetic variants associated with metabolic traits and multiple disease outcomes can be used to validate therapeutic targets at an early stage in the drug development process.

Efficacy and Acceptability of Glycemic Control of Glucagon-Like Peptide-1 Receptor Agonists among Type 2 Diabetes: A Systematic Review and Network Meta-Analysis

Objective

To synthesize current evidence of the impact of Glucagon-like peptide-1 receptor agonists (GLP-1 RAs) on hypoglycemia, treatment discontinuation and glycemic level in patients with type 2 diabetes.

Design

Systematic review and network meta-analysis.

Data Sources

Literature search (Medline, Embase, the Cochrane library), website of clinical trial, bibliographies of published systematic reviews.

Eligibility Criteria

Randomized controlled trials with available data comparing GLP-1 RAs with placebo or traditional anti-diabetic drugs in patients with type 2 diabetes.

Data Synthesis

Traditional pairwise meta-analyses within DerSimonian-Laird random effects model and network meta-analysis within a Bayesian framework were performed to calculate odds ratios for the incidence of hypoglycemia, treatment discontinuation, HbA1c<7.0% and HbA1c<6.5%. Ranking probabilities for all treatments were estimated to obtain a treatment hierarchy using the surface under the cumulative ranking curve (SUCRA) and mean ranks.

Results

78 trials with 13 treatments were included. Overall, all GLP-1 RAs except for albiglutide increased the risk of hypoglycemia when compared to placebo. Reduction in the incidence of hypoglycemia was found for all GLP-1 RAs versus insulin (except for dulaglutide) and sulphonylureas. For the incidence of treatment discontinuation, increase was found for exenatide, liraglutide, lixisenatide and taspoglutide versus placebo, insulin and sitagliptin. For glycemic level, decrease was found for all GLP-1 RAs versus placebo. Dulaglutide, exenatide long-acting release (exe_lar), liraglutide and taspoglutide had significant lowering effect when compared with sitagliptin (HbA1c<7.0%) and insulin (HbA1c<6.5%). Finally, according to SUCRAs, placebo, thiazolidinediones and albiglutide had the best decrease effect on hypoglycemia; sulphanylureas, sitagliptin and insulin decrease the incidence of treatment discontinuation most; exe_lar and dulaglutide had the highest impact on glycemic level among 13 treatments.

Conclusions

Among 13 treatments, GLP-1 RAs had a significant reduction with glycemic level but a slight increase effect on hypoglycemia and treatment discontinuation. While albiglutide had the best decrease effect on hypoglycemia and treatment discontinuation among all GLP-1 RAs. However, further evidence is necessary for more conclusive inferences on mechanisms underlying the rise in hypoglycemia.

The placebo response of injectable GLP-1 receptor agonists vs. oral DPP-4 inhibitors and SGLT-2 inhibitors: a systematic review and meta-analysis

AIMS

The size of the placebo response in type 2 diabetes (T2DM) treatment and its relation to the route of drug administration have not been systematically reviewed. We aimed to determine weight loss, change in HbA1c and incidence of adverse events after treatment with injectable placebo GLP-1 receptor agonist (GLP-1ra), compared with oral placebo DPP-4 inhibitor (DPP-4i) and placebo SGLT-2 inhibitor (SGLT-2i).

METHODS

PubMed, EMBASE and Central were searched up to September 2014 for randomized placebo controlled trials investigating GLP-1ra, DPP-4i or SGLT2-i. Data on placebo groups were extracted and pooled using a generic inverse variance random effects model.

RESULTS

Sixty-seven trials were included, involving 2522, 5290 and 2028 patients randomized to placebo GLP-1ra, placebo DPP-4i and placebo SGLT-2i, respectively. Body weight decreased by -0.67 kg (95% CI -1.03, -0.31) after treatment with placebo GLP-1ra (-0.76 kg [95% CI -1.10, -0.43] with placebo short acting GLP-1ra and -0.32 kg [95% CI -1.75, 1.10] with placebo long acting GLP-1ra) and by -0.31 kg (95% CI -0.64, 0.01) with placebo DPP-4i (P = 0.06 for difference with placebo short acting GLP-1ra). Placebo SGLT-2i resulted in an intermediate -0.48 kg (95% CI -0.81, -0.15) weight loss. Weight loss with placebo showed a strong correlation with the active comparator drug (r(2)  = 0.40-0.78). HbA1c changed little with placebo treatment (-0.23%, 0.10% and -0.13% for placebo GLP-1ra, DPP-4i and SGLT-2i). Adverse events occurred frequently with placebo, were often similar to the active comparator drug and led to drop-out in 2.0-2.7% of cases.

CONCLUSIONS

The response to placebo treatment was related to its active comparator, with injectable placebo GLP-1ra showing a relevant response on weight, whereas oral placebo DPP4i showed no significant response. These findings may suggest that subjective expectations influence T2DM treatment efficacy, which can possibly be employed therapeutically.

Efficacy and tolerability of exenatide twice daily and exenatide once weekly in Asian versus White patients with type 2 diabetes mellitus: A pooled analysis

AIMS

The efficacy and safety of exenatide twice daily (BID) and once weekly (QW) were assessed in Asian versus White patients with type 2 diabetes mellitus (T2DM).

METHODS

This post-hoc pooled analysis evaluated patients receiving 10μg exenatide BID for 12-30 weeks or 2mg exenatide QW for 24-30 weeks in exenatide clinical development program trials. Race was self-identified.

RESULTS

A total of 4625 patients were included (exenatide BID: Asian, n=787; White, n=2223; exenatide QW: Asian, n=511; White, n=1104). At study end, glycated hemoglobin (HbA1c), fasting glucose (FG), body weight, post-prandial glucose (PPG), and PPG excursions were significantly reduced (all P<0.0001 vs baseline). For exenatide BID, HbA1c reduction was greater in Asians (P<0.0001 vs Whites), whereas HbA1c reduction did not differ by race for exenatide QW. FG reduction did not differ by race for either exenatide formulation. Weight reduction was significantly greater in Whites (P<0.0001 vs Asians), regardless of exenatide formulation. PPG reduction was greater in Asians (P<0.0001 vs Whites) for exenatide BID but did not differ by race for exenatide QW. For exenatide BID, reductions in PPG excursions for all meals were significantly greater in Asians (P<0.0001 vs Whites), whereas only post-breakfast and post-lunch excursions were significantly greater in Asians for exenatide QW (P=0.0009 and P=0.0189 vs Whites, respectively). Common adverse events included nausea, headache, and diarrhea.

CONCLUSIONS

Exenatide BID and QW improved glycemic control, including PPG, in Asian and White patients with T2DM. With exenatide BID, Asian patients exhibited significantly greater reductions in HbA1c and PPG than White patients. Both exenatide formulations were well tolerated in both groups.

Glucagon-like peptide-1 receptor agonists in the treatment of type 2 diabetes: Past, present, and future

Glucagon-like peptide-1 (GLP-1)-based therapy improves glycaemic control through multiple mechanisms, with a low risk of hypoglycaemia and the additional benefit of clinically relevant weight loss. Since Starling and Bayliss first proposed the existence of intestinal secretions that stimulate the pancreas, tremendous progress has been made in the area of incretins. As a number of GLP-1 receptor agonists (GLP-1 RAs) continue to become available, physicians will soon face the challenge of selecting the right option customized to their patient's needs. The following discussion, derived from an extensive literature search using the PubMed database, applying the terms incretin, GLP-1, exenatide, liraglutide, albiglutide, dulaglutide, lixisenatide, semaglutide, and taspoglutide, provides a comprehensive review of existing and upcoming molecules in the GLP-1 RA class in terms of their structure, pharmacological profiles, efficacy, safety, and convenience. Search Methodology: A literature search was conducted using the PubMed database, applying the terms incretin, GLP-1, exenatide, liraglutide, albiglutide, dulaglutide, lixisenatide, semaglutide, and taspoglutide. Relevant articles were those that discussed structural, pharmacokinetic and pharmacodynamic differences, classification, long-acting and short-acting GLP-1 RAs, phase 3 trials, and expert opinions. Additional targeted searches were conducted on diabetes treatment guidelines and reviews on safety, as well as the American Diabetes Association/European Society for Study of Diabetes (ADA/EASD) statement on pancreatic safety.

A systematic review of the safety of incretin-based therapies in type 2 diabetes

INTRODUCTION

Large randomized clinical trials have demonstrated that incretin-based therapies provide effective glycemic control in type 2 diabetes. Long-term safety assessments are ongoing.

METHODS

This systematic review of incretin-based therapy safety is based on 112 randomized clinical trials of duration ≥26 weeks published between January 2000 and February 2015 in patients with type 2 diabetes.

RESULTS

As expected, hypoglycemia rates were lower with dipeptidyl peptidase-4 inhibitors (DPP-4is) and glucagon-like peptide-1 receptor agonists (GLP-1 RAs) versus other oral antidiabetic drugs and insulin. The most common adverse events were infection and infestation (DPP-4is) and gastrointestinal (GLP-1 RAs). Pancreatitis cases were rare across all studies and, in the SAVOR-TIMI and EXAMINE trials, pancreatitis rates were similar in DPP-4i- and placebo-treated patients. No thyroid tumors were reported, and increased risk of cardiovascular events was not associated with DPP-4is in SAVOR-TIMI and EXAMINE, albeit over a short follow-up period.

CONCLUSIONS

Overall, incretin-based therapies were well tolerated; however, their long-term safety profile should continue to be periodically assessed.

Treatment potential of the GLP-1 receptor agonists in type 2 diabetes mellitus: a review

Over the last decade, the discovery of glucagon-like peptide 1 receptor agonists (GLP-1 RAs) has increased the treatment options for patients with type 2 diabetes mellitus (T2DM). GLP-1 RAs mimic the effects of native GLP-1, which increases insulin secretion, inhibits glucagon secretion, increases satiety and slows gastric emptying. This review evaluates the phase III trials for all approved GLP-1 RAs and reports that all GLP-1 RAs decrease HbA1c, fasting plasma glucose, and lead to a reduction in body weight in the majority of trials. The most common adverse events are nausea and other gastrointestinal discomfort, while hypoglycaemia is rarely reported when GLP-1 RAs not are combined with sulfonylurea or insulin. Treatment options in the near future will include co-formulations of basal insulin and a GLP-1 RA.

The value of short- and long-acting glucagon-like peptide-1 agonists in the management of type 2 diabetes mellitus: experience with exenatide

BACKGROUND

Only about half of patients with type 2 diabetes treated with antihyperglycemic drugs achieve glycemic control (HbA1c <7%), most commonly due to poor treatment adherence. Glucagon-like peptide-1 (GLP-1) receptor agonists act on multiple targets involved in glucose homeostasis and have a low risk of causing hypoglycemia. While GLP-1 receptor (GLP-1R) agonists share the same mechanism of action, clinical profiles of individual agents differ, particularly between short- and long-acting agents. In this article, recent findings regarding the pharmacology of GLP-1 agonists are reviewed, and the clinical effects of short- versus long-acting agents are compared.

DATA SOURCES

Relevant articles were identified through a search of PubMed using the keywords glucagon-like peptide-1, GLP-1, glucagon-like peptide-1 receptor agonist, GLP-1R agonist, and exenatide for publications up to 22 May 2015. Supporting data were obtained from additional searches for albiglutide, dulaglutide, liraglutide and lixisenatide as well as from the bibliographies of key articles.

FINDINGS

Short-acting GLP-1R agonists produce greater reductions in postprandial glucose levels by slowing gastric emptying, whereas long-acting GLP-1R agonists produce greater reductions in fasting blood glucose by stimulating insulin secretion from the pancreas. These characteristics can be exploited to provide individualized treatment to patients. A large body of evidence supports the benefits of short- and long-acting exenatide as add-on therapy in patients with inadequate glycemic control despite maximum tolerated doses of metformin and/or sulfonylurea. Exenatide is generally well tolerated and no new safety concerns were identified during long-term follow-up of up to 5 years. A limitation of this review of short-and long-acting GLP-1 receptor agonists is that it focuses on exenatide rather than all the drugs in this class. However, the focus on a single molecule helps to avoid any confusion that may be introduced as a result of differences in molecular structure and size.

CONCLUSIONS

Short-acting GLP-1R agonists including exenatide are well suited to patients with type 2 diabetes with exaggerated postprandial glucose excursions and for co-administration with basal insulin therapy. Long-acting GLP-1R agonists including once weekly exenatide offer greater convenience and are well suited to patients who require specific control of fasting hyperglycemia.

Exenatide twice daily: a review of its use in the management of patients with type 2 diabetes mellitus

Exenatide, administered subcutaneously twice daily (Byetta(®)), is a synthetic version of the natural peptide exendin-4, which is a glucagon-like peptide-1 (GLP-1) receptor agonist (incretin mimetic). Exenatide binds to the GLP-1 receptor with the same affinity as GLP-1, but has a much longer half-life, since it is not degraded by the enzyme dipeptidyl peptidase-4. Exenatide twice daily enhances glucose-dependent insulin secretion, suppresses inappropriately elevated glucagon secretion, slows gastric emptying and reduces caloric intake. In well-designed clinical trials, adjunctive subcutaneous exenatide 5 or 10 μg twice daily for 16-52 weeks significantly and dose-dependently improved glycaemic control and reduced mean body weight compared with placebo in patients with type 2 diabetes inadequately controlled with oral antihyperglycaemic drugs (OADs) and/or basal insulin. The improvements in glycaemic control and reductions in body weight were stably maintained during long-term therapy (up to 3.5 years). The efficacy of adjunctive exenatide twice daily was generally similar to that of basal, prandial or biphasic insulin, sulfonylureas, rosiglitazone and lixisenatide, and less than that of liraglutide, taspoglutide or exenatide once weekly with respect to reductions in glycated haemoglobin. Exenatide twice daily was generally well tolerated; mild to moderate nausea and vomiting, which decreased with time on therapy, were the most common adverse events. In patients not receiving concomitant sulfonylureas or insulin, the incidence of hypoglycaemia was low; when it did occur, it was generally mild in severity. Thus, adjunctive exenatide twice daily is a valuable option in the treatment of type 2 diabetes inadequately controlled with OADs and/or basal insulin.

The Effect of Glucagon-Like Peptide 1 Receptor Agonists on Weight Loss in Type 2 Diabetes: A Systematic Review and Mixed Treatment Comparison Meta-Analysis

AIMS

To determine the effects of glucagon-like peptide-1 receptor agonists compared with placebo and other anti-diabetic agents on weight loss in overweight or obese patients with type 2 diabetes mellitus.

METHODS

Electronic searches were conducted for randomised controlled trials that compared a glucagon-like peptide-1 receptor agonist therapy at a clinically relevant dose with a comparator treatment (other type 2 diabetes treatment or placebo) in adults with type 2 diabetes and a mean body mass index ≥ 25 kg/m2. Pair-wise meta-analyses and mixed treatment comparisons were conducted to examine the difference in weight change at six months between the glucagon-like peptide-1 receptor agonists and each comparator.

RESULTS

In the mixed treatment comparison (27 trials), the glucagon-like peptide-1 receptor agonists were the most successful in terms of weight loss; exenatide 2 mg/week: -1.62 kg (95% CrI: -2.95 kg, -0.30 kg), exenatide 20 μg: -1.37 kg (95% CI: -222 kg, -0.52 kg), liraglutide 1.2 mg: -1.01 kg (95%CrI: -2.41 kg, 0.38 kg) and liraglutide 1.8 mg: -1.51 kg (95% CI: -2.67 kg, -0.37 kg) compared with placebo. There were no differences between the GLP-1 receptor agonists in terms of weight loss.

CONCLUSIONS

This review provides evidence that glucagon-like peptide-1 receptor agonist therapies are associated with weight loss in overweight or obese patients with type 2 diabetes with no difference in weight loss seen between the different types of GLP-1 receptor agonists assessed.

Effect of GLP-1 receptor agonists on waist circumference among type 2 diabetes patients: a systematic review and network meta-analysis

Glucagon-like peptide-1 receptor agonists (GLP-1RAs) are increasingly used in patients with type 2 diabetes. However, the effect on abdominal obesity has not yet been confirmed. The study aimed to systematically evaluate the effect of GLP-1RAs on waist circumference in patients with type 2 diabetes. MEDLINE, EMBASE, the Cochrane library and www.clinicaltrialgov were searched through October 31, 2013. Randomized controlled trials with available data were selected if they compared GLP-1 RAs with placebo and traditional anti-diabetic drugs with a duration≥8 weeks. Weighted mean difference was estimated using random-effect model. Network meta-analysis was performed to supplement direct comparisons. Seventeen trials with 12 treatments were included. Overall, significant reductions on waist circumference following treatment of liraglutide--1.8 mg once daily (-5.24 cm, 95% CI -7.68, -2.93), liraglutide--1.2 mg once daily (-4.73 cm, 95% CI -6.68, -2.65) and exenatide--10 μg twice daily (-1.34 cm, 95 % CI -2.00, -0.75) were detected versus placebo. The reduction effect was more evident when compared with insulin and thiazolidinediones (range -1.71 to -8.03 cm). Compared with exenatide, liraglutide--0.6 mg once daily, taspoglutide, liraglutide--1.2 mg once daily and liraglutide--1.8 mg once daily significantly decreased waist circumference from -3.32 to -6.01 cm. Besides, liraglutide--1.8 mg once daily significantly decreased waist circumference by -1.73 cm (95 % CI -3.04, -0.55) versus sitagliptin, whereas no significant difference following liraglutide--1.2-mg-once-daily treatment was detected compared with liraglutide--1.8 mg once daily and sitagliptin. Reduction was observed with statistical significance for exenatide--10 μg twice daily compared with exenatide--5 μg twice daily (-1.21 cm, 95% CI -2.43, -0.06). Ranking probability analysis indicated liraglutide--1.8 mg once daily and liraglutide--1.2 mg once daily decreased waist circumference most among all 12 treatments with probability of 98.36% and 91.82%, respectively. Some GLP-1RAs, especially liraglutide--1.8 mg once daily and liraglutide--1.2 mg once daily, were associated with a significant reduction in waist circumference.

Efficacy and tolerability of glucagon-like peptide-1 receptor agonists in patients with type 2 diabetes mellitus

Glucagon-like peptide-1 (GLP-1) has been evaluated for use in the treatment of type 2 diabetes mellitus (T2DM) due to its role in glucose regulation. Four GLP-1 receptor agonists (RAs) are currently indicated for T2DM in the USA. Exenatide and liraglutide are short-acting and require twice-daily and daily dosing, respectively. Two longer acting agents, exenatide long-acting release (LAR) and albiglutide, were formulated to allow for once-weekly dosing. All four GLP-1 RAs have demonstrated reductions in hemoglobin A1c, fasting blood glucose, and body weight both as monotherapy and in combination with first- and second-line diabetes agents including metformin, sulfonylureas, thiazolidinediones, and insulin. Greater glycemic control was seen with liraglutide compared with the other GLP-1 treatment options; however, the two long-acting agents were superior to exenatide twice daily. All agents were well tolerated with most adverse events being mild or moderate in nature. The most common adverse event was transient nausea which typically resolved 4-8 weeks after treatment initiation. Long-acting agents had lower rates of nausea but an increased incidence of injection site reactions. Trials have suggested GLP-1 RAs may improve cardiovascular risk factors including blood pressure, lipid parameters and inflammatory markers. Future trials are needed to confirm the clinical outcomes of these agents. Overall, GLP-1 RAs will provide benefit for patients with T2DM intolerable to or not reaching glycemic goals with first-line agents, especially in patients in need of weight loss.

A multiplicity of targets: evaluating composite endpoint studies of the GLP-1 receptor agonists in type 2 diabetes

OBJECTIVE

Current type 2 diabetes (T2D) treatment guidelines include weight maintenance or loss, avoidance of hypoglycemia, and targets for blood pressure and circulating lipids, in addition to glycemic control. Increasingly, clinical trials and meta-analyses employ composite endpoints to capture the net clinical benefit of a given T2D intervention. Glucagon-like peptide-1 receptor agonists (GLP-1 RAs) represent a new class of injected antihyperglycemic agents that may be well suited to reaching many of these targets among patients failing on metformin monotherapy.

RESEARCH DESIGNS AND METHODS

Using MEDLINE, Embase and Google Scholar, studies were sought that employed composite endpoints and that reported outcomes with exenatide and/or liraglutide. Bibliographies of relevant review articles were consulted to search for additional reports.

RESULTS

Many trials have used the combination of HbA1c <7%, no weight gain and no hypoglycemic episodes as the composite endpoint in evaluating T2D therapies; however, at least 15 other distinct composite endpoints have been reported. Findings were relatively consistent across studies, regardless of how the composite endpoint was defined. Specifically, the GLP-1 RAs appear to be superior to other agents in their efficacy in providing T2D patients failing on metformin with a net clinical benefit, which can include avoidance of hyperglycemia and maintenance or improvement in body weight.

CONCLUSIONS

Use of composite endpoints represents an important advance in T2D. While no single such endpoint has achieved dominance in the field, widely used composite endpoints capture efficacy in glycemic control as well as safety and effects on markers of cardiovascular risk.

Differences in the HbA1c-lowering efficacy of glucagon-like peptide-1 analogues between Asians and non-Asians: a systematic review and meta-analysis

AIMS

To compare the HbA1c-lowering efficacy of glucagon-like peptide-1 (GLP-1) analogues between Asians and non-Asians with type 2 diabetes.

METHODS

We searched randomized controlled trials from MEDLINE, EMBASE, LILACS, CENTRAL and ClinicalTrials.gov. Studies described in English were included if the treatment duration was 12 weeks or more, information about ethnicity and baseline HbA1c values were available and a GLP-1 analogue was compared with a placebo. For the ethnic comparison, we divided the studies into Asian-dominant studies (≥ 50% Asian participants) and non-Asian-dominant studies (<50% Asian participants).

RESULTS

Among the 837 searched studies, 15 trials were included for the meta-analysis. The weighted mean difference of HbA1c with GLP-1 analogues was -1.16% [95% confidence interval (CI) -1.48, -0.85] in the Asian-dominant studies and -0.83% (95% CI -0.97, -0.70) in the non-Asian-dominant studies. The between-group difference was -0.32% (95% CI -0.64, -0.01; p = 0.04). The relative risk (RR) with 95% CIs for achieving the target HbA1c ≤ 7.0% tended to be greater in the Asian-dominant studies [RR 5.7 (3.8, 8.7)] than in the non-Asian-dominant studies [RR 2.8 (2.4, 3.3)]. Body weight changes were similar between the two groups. Hypoglycaemia tended to be more common in Asian-dominant studies (RR 2.8 [2.3, 3.5]) than in non-Asian-dominant studies (RR 1.5 [1.2, 1.8]), but severe hypoglycaemia was very rare in both groups.

CONCLUSION

GLP-1 analogues lower HbA1c more in Asian-dominant studies than in non-Asian-dominant studies. Further studies are warranted to explore the potential mechanisms of the ethnic difference.

Diabetes and cardiovascular disease: focus on glucagon-like peptide-1 based therapies

Type 2 diabetes is a well known risk factor for cardiovascular disease (CVD). While glycemic control has consistently been shown to prevent microvascular complications, large randomized trials have not demonstrated the same consistent beneficial effects of intensive glycemic control in improving cardiovascular (CV) outcomes. Thus, optimal glucose control alone is not sufficient to reduce CV risk. Aggressive management of CV risk factors such as blood pressure, lipids, and body weight is also necessary. A growing body of evidence suggests that the recently available glucagon-like peptide 1 receptor (GLP-1R) agonists have beneficial CV effects beyond glucose control. Studies have demonstrated beneficial effects in the myocardium, endothelium, vasculature and various markers of cardiovascular risk such as body weight, blood pressure and dyslipidemia. Despite the growing evidence, large, randomized, blinded clinical trials with hard CV endpoints have not been performed. Most human studies have been small, and have focused on surrogate endpoints. The findings need to be confirmed by prospective, randomized cardiovascular outcomes trials. In this review we examine the GLP-1R agonist data on weight reduction, blood pressure lowering, beneficial changes in dyslipidemia, and improvements in myocardial and endothelial function. The safety as well as potential role of these agents in treatment regimens for type 2 diabetes is also addressed.

Composite endpoints in trials of type-2 diabetes

Composite endpoints (CEPs) are being used more frequently as outcomes for trials of drugs in type-2 diabetes. We reviewed the literature to determine how CEPs have been used to date in trials of drugs for type-2 diabetes. A systematic search was undertaken on Medline, Embase and Cochrane databases and Clinicaltrials.gov for randomized controlled trials of currently marketed agents including SGLT-2 inhibitors (dapagliflozin), GLP-1 agonists (exenatide, liraglutide) and DPP-4 inhibitors (linagliptin, saxagliptin, sitagliptin and vildagliptin). CEPs used were identified as well as numbers and percentages of patients achieving each. Thirty-six studies were identified that reported results on ≥1 CEP; 15 different CEPs were reported (7 with 2 components, 8 with 3 components). All CEPs addressed goals recommended by the American Diabetes Association (ADA). All included HbA1c<7%; other endpoints measured weight, blood pressure and hypoglycaemic events. Results were obtained for CEPs from 6 months to 2 years. Rates of achieving CEPs decreased with increasing numbers of components and outcomes assessed. CEPs are becoming used as indicators of clinical outcomes in type-2 diabetes trials, but are still not common. More research is required to identify optimal CEPs. Standardization of outcomes and their reporting is needed.

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.

Assessment of pancreatic β-cell function: review of methods and clinical applications

Type 2 diabetes mellitus (T2DM) is characterized by a progressive failure of pancreatic β-cell function (BCF) with insulin resistance. Once insulin over-secretion can no longer compensate for the degree of insulin resistance, hyperglycemia becomes clinically significant and deterioration of residual β-cell reserve accelerates. This pathophysiology has important therapeutic implications. Ideally, therapy should address the underlying pathology and should be started early along the spectrum of decreasing glucose tolerance in order to prevent or slow β-cell failure and reverse insulin resistance. The development of an optimal treatment strategy for each patient requires accurate diagnostic tools for evaluating the underlying state of glucose tolerance. This review focuses on the most widely used methods for measuring BCF within the context of insulin resistance and includes examples of their use in prediabetes and T2DM, with an emphasis on the most recent therapeutic options (dipeptidyl peptidase-4 inhibitors and glucagon-like peptide-1 receptor agonists). Methods of BCF measurement include the homeostasis model assessment (HOMA); oral glucose tolerance tests, intravenous glucose tolerance tests (IVGTT), and meal tolerance tests; and the hyperglycemic clamp procedure. To provide a meaningful evaluation of BCF, it is necessary to interpret all observations within the context of insulin resistance. Therefore, this review also discusses methods utilized to quantitate insulin-dependent glucose metabolism, such as the IVGTT and the euglycemic-hyperinsulinemic clamp procedures. In addition, an example is presented of a mathematical modeling approach that can use data from BCF measurements to develop a better understanding of BCF behavior and the overall status of glucose tolerance.

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.

Blood pressure-lowering effects of GLP-1 receptor agonists exenatide and liraglutide: a meta-analysis of clinical trials

AIMS

Aside from lowering blood glucose, glucagon-like peptide-1 receptor agonists (GLP-1 RAs) attract much attention because of their cardioprotective effects. The aim of this study was to assess the blood pressure-lowering effects of the GLP-1 RAs exenatide and liraglutide compared with other common drugs used to treat type 2 diabetes (T2DM) based on randomized controlled trials (RCTs) including data describing complete blood pressure (BP) changes from baseline.

METHODS

We searched the major databases for published or unpublished RCTs that had been performed in patients with T2DM and compared the effects of exenatide and liraglutide to those of other common drugs used to treat T2DM. The RCTs that included data describing BP changes between the baseline and the end of the study were selected for further analysis.

RESULTS

A total of 16 RCTs that enrolled 3443 patients in the GLP-1 RA treatment group and 2417 subjects in the control group were included in this meta-analysis. The GLP-1 RA exenatide reduced systolic blood pressure (SBP) when compared with both placebo and insulin glargine, with mean differences of -5.24 and -3.46 mmHg, respectively, and with 95% confidence intervals (CI) of -6.88 to -3.59, p < 0.00001 and -3.63 to -3.29, p < 0.00001, respectively. Meanwhile, in the exenatide-treated group, diastolic blood pressure (DBP) was reduced by -5.91 mmHg, with a 95% CI of -7.53 to -4.28, p < 0.00001 compared with the placebo group, and -0.99 mmHg with a 95% CI of -1.12 to -0.87, p < 0.00001 compared with the sitagliptin group. SBP changes in this meta-analysis were assessed in the groups treated with 1.2 or 1.8 mg liraglutide per day. In the 1.2 mg-treated group, liraglutide treatment reduced SBP compared with placebo and glimepiride treatment, with mean differences of -5.60 and -2.38 mmHg, and 95% CIs of -5.84 to -5.36, p < 0.00001 and -4.75 to -0.01, p = 0.05, respectively. In the 1.8-mg-treated group, liraglutide also reduced SBP compared with placebo and glimepiride treatment with mean differences of -4.49 and -2.62 mmHg, and a 95% CI of -4.73 to -4.26, p < 0.00001, and -2.91 to -2.33, p < 0.00001, respectively.

CONCLUSION

Treatment with the GLP-1 RAs exenatide and liraglutide reduced SBP and DBP by 1 to 5 mmHg compared with some other anti-diabetic drugs including insulin, glimepiride and placebo for patients with T2DM. GLP-1 RAs may offer an alternative therapy for these patients and will help provide extra cardiovascular benefits.

Glucagon-like peptide-1 analogues: An overview

Abnormalities of the incretin axis have been implicated in the pathogenesis of type 2 diabetes mellitus. Glucagon-like peptide-1 (GLP-1) and gastroinhibitory intestinal peptide constitutes >90% of all the incretin function. Augmentation of GLP-1 results in improvement of beta cell health in a glucose-dependant manner (post-prandial hyperglycemia) and suppression of glucagon (fasting hyperglycemia), amongst other beneficial pleiotropic effects. Native GLP-1 has a very short plasma half-life and novel methods have been developed to augment its half life, such that its anti-hyperglycemic effects can be exploited. They can be broadly classified as exendin-based therapies (exenatide, exenatide once weekly), DPP-4-resistant analogues (lixisenatide, albiglutide), and analogues of human GLP-1 (liraglutide, taspoglutide). Currently, commercially available analogues are exenatide, exenatide once weekly, and liraglutide. This review aims to provide an overview of most GLP-1 analogues.

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

AIMS

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Evolution of exenatide as a diabetes therapeutic

Type 2 diabetes (T2DM) is a disease of epidemic proportion associated with significant morbidity and excess mortality. Optimal glucose control reduces the risk of microvascular and possibly macrovascular complications due to diabetes. However, glycemic control is rarely optimal and several therapeutic interventions for the treatment of diabetes cause hypoglycemia and weight gain; some may exacerbate cardiovascular risk. Exenatide (synthetic exendin-4) is a glucagon- like peptide-1 receptor (GLP-1R) agonist developed as a first-in-class diabetes therapy. This review presents an overview of the evolution of exenatide as a T2DM treatment, beginning with the seminal preclinical discoveries and continuing through to clinical pharmacology investigations and phase 3 clinical trials. In patients with T2DM, exenatide enhanced glucose-dependent insulin secretion, suppressed inappropriately elevated glucagon secretion, slowed gastric emptying, and enhanced satiety. In controlled phase 3 clinical trials ranging from 12 to 52 weeks, 10-mcg exenatide twice daily (ExBID) reduced mean HbA1c by -0.8% to -1.7% as monotherapy or in combination with metformin (MET), sulfonylureas (SFU), and/or thiazolidinediones (TZD); with mean weight losses of -1.2 kg to -8.0 kg. In controlled phase 3 trials ranging from 24 to 30 weeks, a 2-mg once-weekly exenatide formulation (ExQW) reduced mean HbA1c by -1.3% to -1.9%, with mean weight reductions of -2.3 to -3.7 kg. Exenatide was generally well-tolerated. The most common side effects were gastrointestinal in nature, mild, and transient. Nausea was the most prevalent adverse event. The incidence of hypoglycemia was generally low. By building upon early observations exenatide was successfully developed into an effective diabetes therapy.

Insulin vs GLP-1 analogues in poorly controlled Type 2 diabetic subjects on oral therapy: a meta-analysis

AIM

To compare insulin and GLP-1 analogues therapy on glycemic control in poorly controlled Type 2 diabetes (T2DM) subjects failing on oral therapy.

METHODS

The electronic database PubMed was systematically searched for randomized controlled trial (RCT) with duration >16 weeks comparing the addition of insulin therapy vs glucagon-like peptide (GLP-1) analogues in poorly controlled T2DM subjects on oral therapy.

RESULTS

We identified 7 RCT with 2199 patients of whom 1119 were assigned to insulin therapy and 1080 received a GLP-1 analogue. Both insulin and GLP-1 analogues were effective in lowering glycated hemoglobin (HbA(1c)) with no statistically significant difference between the mean decreases in HbA(1c). However, insulin was more effective than GLP-1 analogues in lowering the fasting plasma glucose concentration, while GLP-1 agonists were more effective in lowering the postprandial glucose concentration. Insulin therapy was associated with weight gain while GLP-1 analogues consistently caused weight loss and the difference between the mean change in body weight between the two therapies was highly statistically significant. Despite a similar decrease in HbA(1c), the risk of hypoglycemia was 35% lower (p=0.001) with GLP-1 therapy compared to insulin. Compared to insulin, GLP-1 analogues caused a significant decrease in systolic blood pressure and were associated with greater rate of gastrointestinal adverse events.

CONCLUSION/INTERPRETATION

In poorly controlled T2DM subjects on oral therapy, GLP-1 analogues and insulin are equally effective in lowering the HbA(1c). However, GLP-1 analogues have additional non-glycemic benefits and lower risk of hypoglycemia. Thus, GLP-1 analogues should be considered as a treatment option in this group of diabetic individuals.

Effects of exenatide and liraglutide on heart rate, blood pressure and body weight: systematic review and meta-analysis

OBJECTIVES

To synthesise current evidence for the effects of exenatide and liraglutide on heart rate, blood pressure and body weight.

DESIGN

Meta-analysis of available data from randomised controlled trials comparing Glucagon-like peptide-1 (GLP-1) analogues with placebo, active antidiabetic drug therapy or lifestyle intervention.

PARTICIPANTS

Patients with type 2 diabetes.

OUTCOME MEASURES

Weighted mean differences between trial arms for changes in heart rate, blood pressure and body weight, after a minimum of 12-week follow-up.

RESULTS

32 trials were included. Overall, GLP-1 agonists increased the heart rate by 1.86 beats/min (bpm) (95% CI 0.85 to 2.87) versus placebo and 1.90 bpm (1.30 to 2.50) versus active control. This effect was more evident for liraglutide and exenatide long-acting release than for exenatide twice daily. GLP-1 agonists decreased systolic blood pressure by -1.79 mm Hg (-2.94 to -0.64) and -2.39 mm Hg (-3.35 to -1.42) compared to placebo and active control, respectively. Reduction in diastolic blood pressure failed to reach statistical significance (-0.54 mm Hg (-1.15 to 0.07) vs placebo and -0.50 mm Hg (-1.24 to 0.24) vs active control). Body weight decreased by -3.31 kg (-4.05 to -2.57) compared to active control, but by only -1.22 kg (-1.51 to -0.93) compared to placebo.

CONCLUSIONS

GLP-1 analogues are associated with a small increase in heart rate and modest reductions in body weight and blood pressure. Mechanisms underlying the rise in heart rate require further investigation.

GLP-1 receptor activated insulin secretion from pancreatic β-cells: mechanism and glucose dependence

The major goal in the treatment of type 2 diabetes mellitus is to control the hyperglycaemia characteristic of the disease. However, treatment with common therapies such as insulin or insulinotrophic sulphonylureas (SU), while effective in reducing hyperglycaemia, may impose a greater risk of hypoglycaemia, as neither therapy is self-regulated by ambient blood glucose concentrations. Hypoglycaemia has been associated with adverse physical and psychological outcomes and may contribute to negative cardiovascular events; hence minimization of hypoglycaemia risk is clinically advantageous. Stimulation of insulin secretion from pancreatic β-cells by glucagon-like peptide 1 receptor (GLP-1R) agonists is known to be glucose-dependent. GLP-1R agonists potentiate glucose-stimulated insulin secretion and have little or no activity on insulin secretion in the absence of elevated blood glucose concentrations. This 'glucose-regulated' activity of GLP-1R agonists makes them useful and potentially safer therapeutics for overall glucose control compared to non-regulated therapies; hyperglycaemia can be reduced with minimal hypoglycaemia. While the inherent mechanism of action of GLP-1R agonists mediates their glucose dependence, studies in rats suggest that SUs may uncouple this dependence. This hypothesis is supported by clinical studies showing that the majority of events of hypoglycaemia in patients treated with GLP-1R agonists occur in patients treated with a concomitant SU. This review aims to discuss the current understanding of the mechanisms by which GLP-1R signalling promotes insulin secretion from pancreatic β-cells via a glucose-dependent process.

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.

Exenatide twice daily: analysis of effectiveness and safety data stratified by age, sex, race, duration of diabetes, and body mass index

BACKGROUND

Exenatide, a glucagon-like peptide-1 receptor agonist, is used twice daily (BID) as monotherapy or adjunctive therapy for the improvement of glycemic control in patients with type 2 diabetes mellitus. The purpose of this pooled analysis was to evaluate the safety and efficacy of exenatide BID in patients stratified by various demographic characteristics.

METHODS

This post hoc analysis included data from 16 randomized controlled trials in which patients with type 2 diabetes mellitus were treated with 10-μg exenatide BID. Each patient was classified into subgroups on the basis of his or her baseline values for age (< 65 or ≥ 65 years), sex (male or female), race (white, black, Asian, or Hispanic), duration of diabetes (< 10 years or ≥ 10 years), and body mass index (BMI; ≥ 20 to < 25, ≥ 25 to < 30, ≥ 30 to < 35, or ≥ 35 kg/m(2)).

RESULTS

A total of 2067 patients were included. All groups experienced significant improvements in glycated hemoglobin, fasting plasma glucose levels (other than black patients, who had a relatively low baseline fasting plasma glucose level), and body weight from baseline to endpoint. Most groups had significant improvements in systolic blood pressure. All of the age, sex, and duration of diabetes groups experienced significant improvements in lipid levels (other than high-density lipoprotein cholesterol). Whites and Asians generally experienced significant improvements in lipid levels, whereas blacks and Hispanics did not. Significant improvements in lipid levels were generally seen across BMI groups. The most common adverse events overall were nausea (38.6%), hypoglycemia (28.4%), and vomiting (14.0%). Hypoglycemia was more common overall in patients who were taking a concomitant sulfonylurea than it was in patients who were not.

CONCLUSION

In this pooled analysis, exenatide BID improved glycemic control and body weight, and had generally beneficial effects on blood pressure and lipid levels in patients regardless of baseline age, sex, race, duration of diabetes, or BMI. Gastrointestinal events were the most common adverse events.

TRIAL REGISTRATION

www.ClinicalTrials.gov [NCT00039026, NCT00039013, NCT00082381, NCT00035984, NCT00082407, NCT00381342, NCT00360334, NCT00375492, NCT00603239, NCT00765817, NCT00577824, NCT00434954].

A review of exenatide: optimizing glycemic control and associated cardiovascular risk factors in type 2 diabetes

Type 2 diabetes mellitus (T2DM) is a well-recognized risk factor for the development of cardiovascular disease. With an increasing prevalence of obesity, this risk has increased further. Management of T2DM in obese patients is particularly challenging as treatment with the majority of glucose-lowering agents results in weight gain. Thus, the development of a therapeutic option which could improve glycemic control without weight gain or hypoglycemia, such as the glucagon-like peptide-1 (GLP-1) analog exenatide, is a welcome addition to the currently available therapies in the management of T2DM. With recognition and better understanding of the role of incretin hormones in T2DM, exenatide was developed and introduced into clinical practice in 2005. Both randomized controlled trials and retrospective observational studies have shown that treatment with exenatide not only improves glycemic control, with a low risk of hypoglycemia, but also results in concurrent weight loss and the additional benefit of improvement in cardiovascular risk factors. This article will provide an overview of both short- and long-acting exenatide in the management of T2DM and associated cardiovascular risk factors.

Safety of exenatide once weekly in patients with type 2 diabetes mellitus treated with a thiazolidinedione alone or in combination with metformin for 2 years

BACKGROUND

Patients with type 2 diabetes mellitus are routinely treated with combinations of glucose-lowering agents. The adverse event (AE) profile and effects on glycemic control have not been assessed for the glucagon-like peptide-1 receptor agonist exenatide once weekly in combination with a thiazolidinedione (TZD) with or without metformin.

OBJECTIVE

This study was conducted to examine the long-term safety profile and changes in glycemic control and weight for exenatide once weekly with TZD with or without metformin in patients with type 2 diabetes mellitus over 2 years.

METHODS

In this single-arm, open-label trial with treatment up to 104 or 117 weeks, patients received 2 mg exenatide once weekly while continuing treatment with a TZD with or without metformin. Patients were either exenatide-naïve before this study or had previously received exenatide twice daily, which was discontinued on initiating exenatide once weekly. Patients were on a stable dosage of TZD (rosiglitazone or pioglitazone) and, if applicable, metformin. Treatment-emergent AEs were defined as those first occurring or worsening post baseline. Descriptive statistics were used for absolute and change-from-baseline data, and a one-sample t test for within-group change in glycosylated hemoglobin (HbA(1c)).

RESULTS

Of 134 patients in the intent-to-treat population (baseline mean [SD] HbA(1c),7.2% [1.0%]), 44 were exenatide-naïve (baseline HbA(1c), 7.8% [1.0%]) and 90 switched from exenatide twice daily (baseline HbA(1c), 7.0% [0.8%]). Of intent-to-treat patients, 106 (79%) completed the final treatment visit (week 104 or week 117). The most common AEs were nausea (17% of patients) and injection-site nodule (12% of patients). Serious AEs were reported in 14% of patients and 5% withdrew because of a treatment-emergent AE. No identifiable pattern of serious AEs was observed. There were 4 reports of edema and no reports of heart failure. No major hypoglycemia was reported; minor hypoglycemia was reported in 4% of patients. Exenatide-naïve patients experienced mean (SE) HbA(1c) reductions of -0.7% (0.2%) and weight reductions of -2.7 (0.8) kg, whereas patients with prior exposure to exenatide twice daily experienced a reduction of -0.4% (0.1%) in HbA(1c) and no change in weight.

CONCLUSIONS

Adverse events over 2 years were consistent with the reported safety profiles of exenatide once weekly and TZDs. Exenatide-naïve patients experienced improvements in HbA(1c) and weight, while patients with the benefit of prior exenatide therapy experienced an additional reduction from baseline in HbA(1c) and no additional change in weight after 2 years. ClinicalTrials.gov identifier: NCT00753896.

Use of concomitant glucose-lowering therapies and associated treatment results observed in clinical trials of twice-daily exenatide

OBJECTIVE

To explore, by post hoc analyses of pooled data, the efficacy and safety of the use of exenatide twice daily (BID) in patients stratified by baseline glucose-lowering therapies.

METHODS

Patients with type 2 diabetes from long-term randomized controlled trials who were treated with exenatide BID were classified into concomitant medication groups on the basis of background treatment (diet and exercise only, metformin only, sulfonylurea only, thiazolidinedione only, metformin + sulfonylurea, metformin + thiazolidinedione, or insulin with or without other oral antihyperglycemic medications). Seventeen studies were included in the analyses (N = 2,096).

RESULTS

In these analyses of patients treated with exenatide BID for 12 to 30 weeks, there were significant decreases from baseline in hemoglobin A(1c) (A1C) and fasting glucose levels in all groups and significant decreases from baseline in body weight in all groups except the thiazolidinedione-only group. The decrease in A1C appeared to be greater in the insulin group than in the other groups, likely because the insulin dose was titrated whereas doses of concomitant antihyperglycemic medications were generally not titrated. Overall, changes in blood pressure and lipids were small. Across all groups, the most common adverse effects were gastrointestinal events. Hypoglycemia was more common in the sulfonylurea-only, metformin + sulfonylurea, and insulin groups than it was in the other concomitant medication groups.

CONCLUSION

The use of exenatide BID across a wide range of background therapies was associated with reductions in A1C, fasting glucose, and body weight. Gastrointestinal adverse events were common.

Efficacy of GLP-1 receptor agonists and DPP-4 inhibitors: meta-analysis and systematic review

BACKGROUND

Considerable clinical data on the treatment of type 2 diabetes with incretin-based therapies (glucagon-like peptide 1 receptor agonists [GLP-1RAs] and dipeptidyl-peptidase IV [DPP-4] inhibitors) are available.

OBJECTIVE

This meta-analysis was performed to support the understanding of the overall evidence by summarizing the findings from studies of the incretin-based therapies.

METHODS

The MEDLINE, EMBASE, BIOSIS, and BIOSIS trial databases were searched for relevant literature published between January 1, 1990, and June 30, 2011. Search terms included GLP-1, DPP-4, the names of drugs that have been approved by the US Food and Drug Administration for the treatment of diabetes, and the names of drugs that have not been approved but are in late-stage research. Studies were included if they were randomized controlled trials of 12 to 52 weeks' duration and having change from baseline in hemoglobin (Hb) A(1c) as the primary end point. The random effects meta-analyses models examined HbA(1c), fasting plasma glucose (FPG), and body weight for individual therapies, but did not compare effects between therapies.

RESULTS

The reviewers identified 362 unique clinical studies, of which 80 were eligible for inclusion in the present meta-analysis. Mean baseline HbA(1c) values ranged from 7.4% to 10.3% (GLP-1RA studies) and 7.2% to 9.3% (DPP-4 inhibitor studies). The highest maintenance doses of the GLP-1RAs and the DPP-4 inhibitors were associated with changes from baseline in mean HbA(1c) of -1.1% to -1.6% and -0.6% to -1.1%, respectively. Mean reductions in FPG with exenatide once weekly (QW) or liraglutide once daily were apparently greater than those with exenatide twice daily (BID) and the DPP-4 inhibitors, with the exception of vildagliptin. Mean weight losses with the GLP-1RAs and the DPP-4 inhibitors were >-2.0 and -0.2 to -0.6 kg, respectively. The limitations of the present analysis included a lack of adjustment for placebo use and interstudy heterogeneity associated with differences in methodology (eg, management of concurrent medications, blinding, criteria for treatment discontinuation).

CONCLUSIONS

All of the incretin-based therapies in the present meta-analysis were associated with significant reductions from baseline in HbA(1c) and FPG. Further direct comparative studies between the GLP-1RAs and the DPP-4 inhibitors and within the GLP-1RA class are justified.

The role of self-monitoring of blood glucose in glucagon-like peptide-1-based treatment approaches: a European expert recommendation

The role of glucagon-like peptide (GLP)-1-based treatment approaches for type 2 diabetes mellitus (T2DM) is increasing. Although self-monitoring of blood glucose (SMBG) has been performed in numerous studies on GLP-1 analogs and dipeptidyl peptidase-4 inhibitors, the potential role of SMBG in GLP-1-based treatment strategies has not been elaborated. The expert recommendation suggests individualized SMBG strategies in GLP-1-based treatment approaches and suggests simple and clinically applicable SMBG schemes. Potential benefits of SMBG in GLP-1-based treatment approaches are early assessment of treatment success or failure, timely modification of treatment, detection of hypoglycemic episodes, assessment of glucose excursions, and support of diabetes management and diabetes education. Its length and frequency should depend on the clinical setting and the quality of metabolic control. It is considered to play an important role for the optimization of diabetes management in T2DM patients treated with GLP-1-based approaches.

Efficacy and safety of exenatide once weekly versus metformin, pioglitazone, and sitagliptin used as monotherapy in drug-naive patients with type 2 diabetes (DURATION-4): a 26-week double-blind study

OBJECTIVE

To test the safety and efficacy of exenatide once weekly (EQW) compared with metformin (MET), pioglitazone (PIO), and sitagliptin (SITA) over 26 weeks, in suboptimally treated (diet and exercise) drug-naive patients with type 2 diabetes.

RESEARCH DESIGN AND METHODS

Patients were randomized to subcutaneous (SC) EQW 2.0 mg + oral placebo (n = 248), MET 2,000 mg/day + SC placebo (n = 246), PIO 45 mg/day + SC placebo (n = 163), or SITA 100 mg/day + SC placebo (n = 163) for 26 weeks. MET and PIO therapies were increased to maximum-tolerated dosages. Injections with EQW or placebo were administered weekly, while oral medication or placebo was administered daily.

RESULTS

Baseline characteristics were as follows: 59% men, 67% Caucasian, mean age 54 years, HbA(1c) 8.5%, fasting serum glucose 9.9 mmol/L, body weight 87.0 kg, and diabetes duration 2.7 years. HbA(1c) reductions (%) at 26 weeks (least-squares means) with EQW versus MET, PIO, and SITA were -1.53 vs. -1.48 (P = 0.620), -1.63 (P = 0.328), and -1.15 (P < 0.001), respectively. Weight changes (kg) were -2.0 vs. -2.0 (P = 0.892), +1.5 (P < 0.001), and -0.8 (P < 0.001), respectively. Common adverse events were as follows: EQW, nausea (11.3%) and diarrhea (10.9%); MET, diarrhea (12.6%) and headache (12.2%); PIO, nasopharyngitis (8.6%) and headache (8.0%); and SIT, nasopharyngitis (9.8%) and headache (9.2%). Minor (confirmed) hypoglycemia was rarely reported. No major hypoglycemia occurred.

CONCLUSIONS

EQW was noninferior to MET but not PIO and superior to SITA with regard to HbA(1c) reduction at 26 weeks. Of the agents studied, EQW and MET provided similar improvements in glycemic control along with the benefit of weight reduction and no increased risk of hypoglycemia.