Patient-reported outcomes following treatment with the human GLP-1 analogue liraglutide or glimepiride in monotherapy: results from a randomized controlled trial in patients with type 2 diabetes

The effect of GLP-1RAs on mental health and psychotropics-induced metabolic disorders: A systematic review

BACKGROUND

Mental illnesses and psychotropic drug use are associated with an increased risk of weight gain and metabolic disorders. Growing evidence suggests that agonists of the glucagon-like peptide-1 receptor (GLP-1RAs) might be safe and effective weight loss medications. However, the current evidence for the use of GLP-1RAs in individuals with obesity and mental illness is limited.

OBJECTIVE

Evaluation of the safety and the impact of GLP-1RAs on mental health and psychotropics-induced metabolic disorders such as obesity and type 2 diabetes (T2D).

METHODS

A literature search from January 1st, 2010 to August 31st, 2024 was conducted using PubMed and Cochrane Library online databases. Studies comprising adults with obesity or/and T2D and mental illness were included. Studies that examined individuals with obesity or/and T2D without mental illness and completed psychiatric questionnaires before and after GLP-1RAs treatment were also included.

RESULTS

From the 36 included studies 18 examined the weight-reducing effect of GLP-1RAs in patients with mental disorders and the other studies examined patients without mental illness. GLP-1RAs lead to a significant weight loss and improvement of glycemic control in patients with mental illness on psychotropics. They showed a beneficial effect on mental health in patients with and without mental disorders and were not associated with a worsening of mental state, suicidality, new-onset mental illness, or increased psychiatric admissions.

CONCLUSION

GLP-1RAs are safe and effective weight loss treatments for individuals with obesity and mental illness exerting a positive effect on mental state and quality of life. There is a need for RCTs with larger sample sizes, a longer treatment duration and longer follow-up periods to evaluate the long-term effect of GLP-1RAs. It would be of great interest to conduct studies investigating the use of GLP-1RAs with the purpose to treat mental illness in order to directly assess their use in improving mental health.

Continuous Glucose Monitoring Profiles and Health Outcomes After Dapagliflozin Plus Saxagliptin vs Insulin Glargine

CONTEXT

Glycemic variability and hypoglycemia during diabetes treatment may impact therapeutic effectiveness and safety, even when glycated hemoglobin (HbA1c) reduction is comparable between therapies.

OBJECTIVE

We employed masked continuous glucose monitoring (CGM) during a randomized trial of dapagliflozin plus saxagliptin (DAPA + SAXA) vs insulin glargine (INS) to compare glucose variability and patient-reported outcomes (PROs).

DESIGN

24-week substudy of a randomized, open-label, 2-arm, parallel-group, phase 3b study.

SETTING

Multicenter study (112 centers in 11 countries).

PATIENTS

283 adults with type 2 diabetes (T2D) inadequately controlled with metformin ± sulfonylurea.

INTERVENTIONS

DAPA + SAXA vs INS.

MAIN OUTCOME MEASURES

Changes in CGM profiles, HbA1c, and PROs.

RESULTS

Changes from baseline in HbA1c with DAPA + SAXA were similar to those observed with INS, with mean difference [95% confidence interval] between decreases of -0.12% [-0.37 to 0.12%], P = .33. CGM analytics were more favorable for DAPA + SAXA, including greater percent time in range (> 3.9 and ≤ 10 mmol/L; 34.3 ± 1.9 vs 28.5 ± 1.9%, P = .033), lower percent time with nocturnal hypoglycemia (area under the curve ≤ 3.9 mmol/L; 0.6 ± 0.5 vs 2.7 ± 0.5%, P = .007), and smaller mean amplitude of glycemic excursions (-0.7 ± 0.1 vs -0.3 ± 0.1 mmol/L, P = .017). Improvements in CGM were associated with greater satisfaction, better body weight image, less weight interference, and improved mental and emotional well-being.

CONCLUSION

DAPA + SAXA and INS were equally effective in reducing HbA1c at 24 weeks, but people with T2D treated with DAPA + SAXA achieved greater time in range, greater reductions in glycemic excursions and variability, less time with hypoglycemia, and improved patient-reported health outcomes.

Glucagon-like peptide receptor agonists and risk for depression

AIMS

Package labeling for weight loss formulations of semaglutide and liraglutide include a warning for suicidal thoughts and behaviors. The objective was to examine the association between glucagon-like peptide-1 receptor agonists (GLP-1RA) and incident depression.

METHODS

This retrospective cohort study compared Veterans Health Administration patients initiated on a GLP-1RA versus a dipeptidyl peptidase-4 inhibitor (DPP-4i) between June 1, 2013 and June 30, 2020. The primary outcome was incident depression, defined as a new diagnosis of depression or new antidepressant prescription, within 1 year following drug initiation. Multivariable log-binomial regression was used to estimate relative risk, adjusted for confounding factors including patient demographics, comorbid conditions, and prior medication.

RESULTS

Of 34,130 patients initiated on a GLP-1RA and 105,478 initiated on a DPP-4i, incident depression occurred in 7.7 % (n= 2263) and 6.3 % (n= 6602), respectively. After adjustment, the relative risk was 1.02 (95 % CI: 0.97 - 1.07), thus failing to demonstrate a significant increase in risk for incident depression following initiation of a GLP-1RA compared to DPP-4i. Relative risk estimates in all sensitivity analyses were also non-significant.

CONCLUSIONS

This study did not demonstrate a significant increase in risk for incident depression following GLP-1RA initiation.

Dorsolateral septum GLP-1R neurons regulate feeding via lateral hypothalamic projections

OBJECTIVE

Although glucagon-like peptide 1 (GLP-1) is known to regulate feeding, the central mechanisms contributing to this function remain enigmatic. Here, we aim to test the role of neurons expressing GLP-1 receptors (GLP-1R) in the dorsolateral septum (dLS; dLSGLP-1R) that project to the lateral hypothalamic area (LHA) on food intake and determine the relationship with feeding regulation.

METHODS

Using chemogenetic manipulations, we assessed how activation or inhibition of dLSGLP-1R neurons affected food intake in Glp1r-ires-Cre mice. Then, we used channelrhodopsin-assisted circuit mapping, chemogenetics, and electrophysiological recordings to identify and assess the role of the pathway from dLSGLP-1R →LHA projections in regulating food intake.

RESULTS

Chemogenetic inhibition of dLSGLP-1R neurons increases food intake. LHA is a major downstream target of dLSGLP-1R neurons. The dLSGLP-1R→LHA projections are GABAergic, and chemogenetic inhibition of this pathway also promotes food intake. While chemogenetic activation of dLSGLP-1R→LHA projections modestly decreases food intake, optogenetic stimulation of the dLSGLP-1R→LHA projection terminals in the LHA rapidly suppresses feeding behavior. Finally, we demonstrate that the GLP-1R agonist, Exendin 4 enhances dLSGLP-1R →LHA GABA release.

CONCLUSIONS

Together, these results demonstrate that dLS-GLP-1R neurons and the inhibitory pathway to LHA can regulate feeding behavior, which might serve as a potential therapeutic target for the treatment of eating disorders or obesity.

Newer Pharmacologic Treatments in Adults With Type 2 Diabetes: A Systematic Review and Network Meta-analysis for the American College of Physicians

BACKGROUND

Newer diabetes medications may have beneficial effects on mortality, cardiovascular outcomes, and renal outcomes.

PURPOSE

To evaluate the effectiveness, comparative effectiveness, and harms of sodium-glucose cotransporter-2 (SGLT2) inhibitors, glucagon-like peptide-1 (GLP1) agonists, dipeptidyl peptidase-4 (DPP4) inhibitors, and long-acting insulins as monotherapy or combination therapy in adults with type 2 diabetes mellitus (T2DM).

DATA SOURCES

MEDLINE and EMBASE for randomized controlled trials (RCTs) published from 2010 through January 2023.

STUDY SELECTION

RCTs lasting at least 52 weeks that included at least 500 adults with T2DM receiving eligible medications and reported any outcomes of interest.

DATA EXTRACTION

Data were abstracted by 1 reviewer and verified by a second. Independent, dual assessments of risk of bias and certainty of evidence (CoE) were done.

DATA SYNTHESIS

A total of 130 publications from 84 RCTs were identified. CoE was appraised using GRADE (Grading of Recommendations Assessment, Development and Evaluation) criteria for direct, indirect, and network meta-analysis (NMA); the highest CoE was reported. Compared with usual care, SGLT2 inhibitors and GLP1 agonists reduce all-cause mortality (high CoE) and major adverse cardiovascular events (MACE) (moderate to high CoE), SGLT2 inhibitors reduce progression of chronic kidney disease (CKD) and heart failure hospitalizations and GLP1 agonists reduce stroke (high CoE), and SGLT2 inhibitors reduce serious adverse events and severe hypoglycemia (high CoE). The threshold for minimally important differences, which was predefined with the American College of Physicians Clinical Guidelines Committee, was not met for these outcomes. Compared with usual care, insulin, tirzepatide, and DPP4 inhibitors do not reduce all-cause mortality (low to high CoE). Compared with insulin, SGLT2 inhibitors and GLP1 agonists reduce all-cause mortality (low to moderate CoE). Compared with DPP4 inhibitors, GLP1 agonists reduce all-cause mortality (moderate CoE). Compared with DPP4 inhibitors and sulfonylurea (SU), SGLT2 inhibitors reduce MACE (moderate to high CoE). Compared with SU and insulin, SGLT2 inhibitors and GLP1 agonists reduce severe hypoglycemia (low to high CoE).

LIMITATIONS

Infrequent direct comparisons between drugs of interest; sparse data for NMA on most outcomes; possible incoherence due to differences in baseline patient characteristics and usual care; insufficient data on predefined subgroups, including demographic subgroups, patients with prior cardiovascular disease, and treatment-naive persons.

CONCLUSION

In adults with T2DM, SGLT2 inhibitors and GLP1 agonists (but not DPP4 inhibitors, insulin, or tirzepatide) reduce all-cause mortality and MACE compared with usual care. SGLT2 inhibitors reduce CKD progression and heart failure hospitalization and GLP1 agonists reduce stroke compared with usual care. Serious adverse events and severe hypoglycemia are less frequent with SGLT2 inhibitors and GLP1 agonists than with insulin or SU.

PRIMARY FUNDING SOURCE

American College of Physicians. (PROSPERO: CRD42022322129).

The Antidepressant Effects of GLP-1 Receptor Agonists: A Systematic Review and Meta-Analysis

AIM/HYPOTHESIS

Emerging evidence suggests that glucagon-like peptide-1 receptor agonists (GLP-1RAs) may exert positive effects in patients with depression. Our aim was to conduct a systematic review and meta-analysis to examine the antidepressant effects of GLP-1RAs.

METHODS

Randomized controlled trials and prospective cohort studies investigating the effects of GLP-1RAs versus placebo or other antidiabetic therapies on depressive symptoms were searched for using multiple electronic sources (CENTRAL, PubMed, EMBASE, PsycINFO, World Health Organization International Clinical Trials Registry Platform, ClinicalTrials.gov, China Network Knowledge Infrastructure, China Biomedical Database, Wan Fang data, and Chinese Scientific Journals Database) from inception to February 16, 2023. We utilized a random effects model to analyze standardized mean differences for the change in depression rating scales comparing GLP-1RA treated groups with control treated groups.

RESULTS

The meta-analysis comprising 2,071 participants included 5 randomized controlled trials and 1 prospective cohort study. The meta-analysis indicated that the change from baseline in depression rating scale scores decreased significantly when patients received treatment with GLP-1RAs compared to control treatments (SMD = -0.12, 95% CI [-0.21, -0.03], pSMD <0.01, I2 = 0%, pQ = 0.52). The subgroup analysis showed that the effects of GLP-1RAs on depressive symptoms were consistent in patients with Type 2 diabetes mellitus (SMD = -0.12, 95% CI [-0.21, -0.03], pSMD <0.01, I2 = 2%, pQ = 0.40).

CONCLUSIONS

Adults treated with GLP-1RAs showed significant reductions in the depression rating scale scores compared to those treated with control substances. Our findings suggest that GLP-1RAs may be a potential treatment for alleviating depressive symptoms in humans.

Unlocking Therapeutic Synergy: Tailoring Drugs for Comorbidities such as Depression and Diabetes through Identical Molecular Targets in Different Cell Types

Research in the field of pharmacology aims to generate new treatments for pathologies. Nowadays, there are an increased number of chronic disorders that severely and durably handicap many patients. Among the most widespread pathologies, obesity, which is often associated with diabetes, is constantly increasing in incidence, and in parallel, neurodegenerative and mood disorders are increasingly affecting many people. For years, these pathologies have been so frequently observed in the population in a concomitant way that they are considered as comorbidities. In fact, common mechanisms are certainly at work in the etiology of these pathologies. The main purpose of this review is to show the value of anticipating the effect of baseline treatment of a condition on its comorbidity in order to obtain concomitant positive actions. One of the implications would be that by understanding and targeting shared molecular mechanisms underlying these conditions, it may be possible to tailor drugs that address both simultaneously. To this end, we firstly remind readers of the close link existing between depression and diabetes and secondly address the potential benefit of the pleiotropic actions of two major active molecules used to treat central and peripheral disorders, first a serotonin reuptake inhibitor (Prozac ®) and then GLP-1R agonists. In the second part, by discussing the therapeutic potential of new experimental antidepressant molecules, we will support the concept that a better understanding of the intracellular signaling pathways targeted by pharmacological agents could lead to future synergistic treatments targeting solely positive effects for comorbidities.

Decreased Risk of Anxiety in Diabetic Patients Receiving Glucagon-like Peptide-1 Receptor Agonist: A Nationwide, Population-Based Cohort Study

Background: Previous findings on using Glucagon-like peptide-1 receptor agonist (GLP1-RA) as an antidepressant were conflicting, lacking large-scale studies. We used population-based data to investigate depression and anxiety risk in diabetic patients receiving the medication.

Methods: From claims records of the National Health Insurance Research Database (NHIRD) of Taiwan, we identified cohorts of 10,690 GLP1-RA users and 42,766 propensity score-matched patients without GLP1-RA use from patients with diabetes mellitus (DM) diagnosed in 2011–2017, matched by age, gender, index year, occupation, urbanization, comorbidities, and medications. Incidence, hazard ratios (HR) and 95% confidence interval (CI) of depression and/or anxiety were estimated by the end of 2017.

Results: The overall combined incidence of anxiety and/or depression was lower in GLP1-RA users than in non-users (6.80 versus 9.36 per 1,000 person-years), with an adjusted HR adjusted hazard ratio (aHR) of 0.8 (95% CI: 0.67–0.95) after controlling for covariates. The absolute incidence reduction was greater in anxiety (2.13 per 1,000 person-years) than in depression (0.41 per 1,000 person-years). The treatment effectiveness was significant for women. Patients taking GLP1-RA for longer than 180 days had the incidence of anxiety reduced to 2.93 per 1,000 person-years, with an aHR of 0.41 (95%CI: 0.27–0.61), compared to non-users. Dulaglutide could significantly decrease risks of both anxiety and depression.

Conclusion: Patients with DM receiving GLP1-RA therapy have a greater reduction of the risk of anxiety than that of depression. Our findings strengthen previous research that advocated possible anti-depressant or anxiolytic effects of GLP1-RA and may lead to improved treatment adherence among patients with DM.

Potential gut-brain mechanisms behind adverse mental health outcomes of bariatric surgery

Bariatric surgery induces sustained weight loss and metabolic benefits via notable effects on the gut-brain axis that lead to alterations in the neuroendocrine regulation of appetite and glycaemia. However, in a subset of patients, bariatric surgery is associated with adverse effects on mental health, including increased risk of suicide or self-harm as well as the emergence of depression and substance use disorders. The contributing factors behind these adverse effects are not well understood. Accumulating evidence indicates that there are important links between gut-derived hormones, microbial and bile acid profiles, and disorders of mood and substance use, which warrant further exploration in the context of changes in gut-brain signalling after bariatric surgery. Understanding the basis of these adverse effects is essential in order to optimize the health and well-being of people undergoing treatment for obesity.

The therapeutic potential of GLP-1 analogues for stress-related eating and role of GLP-1 in stress, emotion and mood: a review

Stress and low mood are powerful triggers for compulsive overeating, a maladaptive form of eating leading to negative physical and mental health consequences. Stress-vulnerable individuals, such as people with obesity, are particularly prone to overconsumption of high energy foods and may use it as a coping mechanism for general life stressors. Recent advances in the treatment of obesity and related co-morbidities have focused on the therapeutic potential of anorexigenic gut hormones, such as glucagon-like peptide 1 (GLP-1), which acts both peripherally and centrally to reduce energy intake. Besides its appetite suppressing effect, GLP-1 acts on areas of the brain involved in stress response and emotion regulation. However, the role of GLP-1 in emotion and stress regulation, and whether it is a viable treatment for stress-induced compulsive overeating, has yet to be established. A thorough review of the pre-clinical literature measuring markers of stress, anxiety and mood after GLP-1 exposure points to potential divergent effects based on temporality. Specifically, acute GLP-1 injection consistently stimulates the physiological stress response in rodents whereas long-term exposure indicates anxiolytic and anti-depressive benefits. However, the limited clinical evidence is not as clear cut. While prolonged GLP-1 analogue treatment in people with type 2 diabetes improved measures of mood and general psychological wellbeing, the mechanisms underlying this may be confounded by associated weight loss and improved blood glucose control. There is a paucity of longitudinal clinical literature on mechanistic pathways by which stress influences eating behavior and how centrally-acting gut hormones such as GLP-1, can modify these. (250).

Effect of Exenatide Use on Cognitive and Affective Functioning in Obese Patients With Type 2 Diabetes Mellitus: Exenatide Use Mediates Depressive Scores Through Increased Perceived Stress Levels

PURPOSE/BACKGROUND

Glucagon-like peptide-1 (GLP-1) is a molecule used to treat type 2 diabetes mellitus (T2DM). Given their widespread expression in the nervous system, GLP-1 receptors also play a role in regulating mood and cognitive function. Here, we aimed to compare obese patients with T2DM, with or without exenatide (a GLP-1R agonist) use on cognitive and affective functioning.

METHODS/PROCEDURES

A total of 43 patients with T2DM (23 on exenatide and 20 without exenatide) were evaluated with the Snaith-Hamilton Pleasure Scale, Cognitive Failures Questionnaire, Patient Health Questionnaire-9 (PHQ-9), Generalized Anxiety Disorder-7, Childhood Trauma Questionnaire, Perceived Stress Scale (PSS), and Chronic Stress Scale, in addition to laboratory-based measures of reward learning (the probabilistic reward task) and working memory (Letter-N-Back task).

FINDINGS/RESULTS

Patients on exenatide had higher body mass index (BMI) (37.88 ± 5.44 vs 35.29 ± 6.30; P = 0.015), PHQ-9 (9.70 ± 4.92 vs 6.70 ± 4.66; P = 0.026), and PSS (29.39 ± 6.70 vs 23.35 ± 7.69; P = 0.015) scores. Other stress scales (Childhood Trauma Questionnaire and Chronic Stress Scale), Generalized Anxiety Disorder-7 scores, response bias, or discriminability as assessed by probabilistic reward task and self-report (Cognitive Failures Questionnaire) and laboratory-based (Letter-N-Back) cognitive measures were not significantly different between groups (both Ps > 0.05). Multivariate linear regression analyses adding BMI and PSS as covariates revealed that although BMI had no effect (P = 0.5), PSS significantly predicted PHQ-9 scores (P = 0.004). Mediation analysis showed that exenatide users reported higher PSS, with greater PSS associated with higher PHQ-9 levels (b = 0.236). There was no evidence on exenatide directly influencing PHQ-9 independent of PSS (c' = 1.573; P = 0.305; 95% bootstrap confidence interval, -1.487 to 4.634).

IMPLICATIONS/CONCLUSIONS

Based on previous research and our findings, exenatide use might be mediating depression scores through disrupting stress responses.

The role of nucleus of the solitary tract glucagon-like peptide-1 and prolactin-releasing peptide neurons in stress: anatomy, physiology and cellular interactions

Neuroendocrine, behavioural and autonomic responses to stressful stimuli are orchestrated by complex neural circuits. The caudal nucleus of the solitary tract (cNTS) in the dorsomedial hindbrain is uniquely positioned to integrate signals of both interoceptive and psychogenic stress. Within the cNTS, glucagon‐like peptide‐1 (GLP‐1) and prolactin‐releasing peptide (PrRP) neurons play crucial roles in organising neural responses to a broad range of stressors. In this review we discuss the anatomical and functional overlap between PrRP and GLP‐1 neurons. We outline their co‐activation in response to stressful stimuli and their importance as mediators of behavioural and physiological stress responses. Finally, we review evidence that PrRP neurons are downstream of GLP‐1 neurons and outline unexplored areas of the research field. Based on the current state‐of‐knowledge, PrRP and GLP‐1 neurons may be compelling targets in the treatment of stress‐related disorders.

Semaglutide improves health-related quality of life versus placebo when added to standard of care in patients with type 2 diabetes at high cardiovascular risk (SUSTAIN 6)

AIM

To assess what drives change in health-related quality of life (HRQoL) in type 2 diabetes in the SUSTAIN 6 trial and identify potential mediators of the treatment effect of semaglutide on HRQoL scores.

MATERIALS AND METHODS

The Short Form (SF)-36v2® questionnaire [comprising physical component summary (PCS) and mental component summary (MCS)] was used to assess changes in HRQoL from baseline to week 104, by treatment, in a prespecified analysis. This post-hoc analysis assessed change in PCS and MCS using the following factors as parameter/covariate, using descriptive statistics and linear regressions: major adverse cardiac events, hypoglycaemia, gastrointestinal adverse events, at least one episode of nausea, vomiting or diarrhoea, and change in glycated haemoglobin (HbA1c), body weight, blood pressure, heart rate and estimated glomerular filtration rate.

RESULTS

Mean change in overall PCS score was +1.0 with semaglutide versus +0.4 with placebo, and +0.5 versus -0.2 for MCS. The treatment effect of semaglutide versus placebo (unadjusted estimate) was 0.7 [(95% confidence interval 0.1, 1.2); P = 0.018] on PCS and this was reduced when adjusted for change in HbA1c [0.4 (-0.2, 1.0), P = .167] and body weight [0.3 (-0.3, 0.9), P = .314]. The unadjusted treatment effect on MCS [0.7 (-0.0, 1.5), P = .054] was only reduced when adjusted for change in HbA1c [0.3 (-0.4, 1.1), P = .397]. When adjusting for all other parameters separately, the estimated effect of semaglutide on PCS and MCS qualitatively did not change.

CONCLUSIONS

Semaglutide improved HRQoL versus placebo; greater improvements with semaglutide versus placebo were possibly mediated, in part, by change in HbA1c and body weight. Clinicaltrials.gov: NCT01720446 (SUSTAIN 6).

Consensus Recommendations on GLP-1 RA Use in the Management of Type 2 Diabetes Mellitus: South Asian Task Force

The advent of incretin mimetics such as glucagon-like peptide-1 receptor agonists (GLP-1 RAs) has enriched the armamentarium for diabetes management owing to their glycaemic as well as extra-glycaemic benefits. The approval status and availability of this class of drugs vary widely across the globe. Being a relatively newer class of drug with numerous benefits, several national and international guidelines are working towards addressing clinical questions pertaining to the optimal use of GLP-1 RAs for the management of diabetes. Although the newer class of drugs are associated with significant benefits such as patient-centric approach, these drugs demand the providers to be vigilant and knowledgeable about the medication. The South Asian population is at higher risk of type 2 diabetes mellitus (T2DM) because of their genetic predisposition and lifestyle changes. Hence, prevention and management of T2DM and its associated complications in this population are of paramount importance. The current report aims to present an overview of current knowledge on GLP-1 RAs based on pragmatic review of the available clinical evidence. In addition, this report is a consensus of expert endocrinologists representing South Asian countries including India, Pakistan, Bangladesh, Nepal, Sri Lanka, Afghanistan and the Maldives on essential recommendations related to the use of GLP-1 RAs in a real-world scenario.

A systematic review of the antidepressant effects of glucagon-like peptide 1 (GLP-1) functional agonists: Further link between metabolism and psychopathology: Special Section on "Translational and Neuroscience Studies in Affective Disorders". Section Editor, Maria Nobile MD, PhD. This Section of JAD focuses on the relevance of translational and neuroscience studies in providing a better understanding of the neural basis of affective disorders. The main aim is to briefly summaries relevant research findings in clinical neuroscience with particular regards to specific innovative topics in mood and anxiety disorders

INTRODUCTION

An increasing amount of preclinical and clinical evidence links together metabolic regulations and psychopathological mechanisms, in particular linking mood disorders with changes in Glycogen Synthase Kinase 3 beta and 5'Adenosine Monophosphate-activated Protein Kinase expression and activity. New hypoglycemic drugs, including thiazolidinediones and glucagon-like peptide 1 (GLP-1) functional agonists, which work by these mechanisms, have also been described as potential antidepressants. The putative role of thiazolidinediones in depression has been already supported, but no clear evidence exists yet for GLP-1 functional agonists. We conducted a systematic review and meta-analysis of the literature to describe the effect of GLP-1 functional agonists on depression rating scales and either support or confute a potential antidepressant role.

METHODS

We searched the PubMed and Scopus databases for terms related to DPP-4 inhibitors and GLP-1 receptor agonists, and depression, including symptoms and rating scales with acronyms and full names. We included longitudinal interventional and observational studies on GLP-1 functional agonists used for depression symptoms. We applied a random effects meta-analysis on standardized mean differences before-after treatment, comparing GLP-1 functional agonists versus control treatments.

RESULTS

Literature searches found 815 papers, 8 of which were eligible for meta-analysis. Both control treatments (-0.67, 95%C.I. -0.99 - -0.36, Z = 4.24, p < 0.0001) and GLP-1 functional agonists (-1.28, 95%C.I. -2.34 - -0.21, Z = 2.35, p = 0.02) resulted in a significant reduction of depression rating scores, although GLP-1 functional agonists tended to be superior. When a selection was made, including only studies conducted on diabetic patients that did not exclude depressed patients, the effect of GLP-1 functional agonists (-2.09, 95%C.I. -2.28 - -1.91, Z = 22.5, p < 0.00001) was significantly superior to that of control treatments (-0.57, 95%C.I. -0.66 - -0.49, Z = 13.6, p < 0.00001).

DISCUSSION

Results of this meta-analysis must be carefully considered, since the amount of studies available was low and heterogeneity was high. If further trials will confirm this hypothesis, GLP-1 functional agonists may be considered as antidepressants, either as adjuncts or in mono-therapy, with a peculiar value for preventing the adverse metabolic effects of long-term antipsychotic therapies used in rehabilitation.

Improvement in treatment satisfaction after switching from liraglutide to dulaglutide in patients with type 2 diabetes: A randomized controlled trial

AIMS/INTRODUCTION

We compared treatment satisfaction in type 2 diabetes patients taking daily and weekly glucagon-like peptide-1 receptor agonists.

MATERIALS AND METHODS

The study was a 12-week, multicenter, open-label, prospective, randomized, parallel-group comparison trial. The participants were Japanese patients with type 2 diabetes being administered with the glucagon-like peptide-1 receptor agonist, liraglutide, daily for >3 months. Patients were randomly assigned to either continue taking liraglutide once daily (Lira group) or switch to dulaglutide once weekly (Dula group). The primary outcome was the change in the Diabetes Treatment Satisfaction Questionnaire score from baseline to week 12 in the two groups. The secondary outcomes comprised changes in the Diabetes Therapy-Related Quality of Life score, body mass and glycemic control.

RESULTS

A total of 33 participants were initially enrolled in the trial, and 31 participants completed the protocol. The change in the Diabetes Treatment Satisfaction Questionnaire score in the Dula group was significantly greater than that in the Lira group (+0.1 ± 4.7 in the Lira group vs +4.9 ± 5.2 in the Dula group; P = 0.013). The change in Diabetes Therapy-Related Quality of Life score in the Dula group was significantly greater than that in the Lira group (-3.7 ± 6.9 vs +8.9 ± 15.1; P = 0.007). There were no significant differences between groups in the changes in body mass, plasma glucose or glycated hemoglobin.

CONCLUSIONS

Weekly administration of dulaglutide was superior to liraglutide with regard to treatment satisfaction in patients with type 2 diabetes, in the absence of any negative effect on glycemic control.

Examining the risk of depression or self-harm associated with incretin-based therapies used to manage hyperglycaemia in patients with type 2 diabetes: a cohort study using the UK Clinical Practice Research Datalink

OBJECTIVES

To compare population-based incidence rates of new-onset depression or self-harm in patients initiating incretin-based therapies with that of sulfonylureas (SU) and other glucose-lowering agents.

DESIGN

Population-based cohort study.

SETTING

Patients attending primary care practices registered with the UK-based Clinical Practice Research Datalink (CPRD).

PARTICIPANTS

Using the UK-based CPRD, we identified two incretin-based therapies cohorts: (1) dipeptidyl peptidase-4 inhibitor (DPP-4i)-cohort, consisting of new users of DPP-4i and SU and (2) glucagon-like peptide-1 receptor agonists (GLP-1RA)-cohort, consisting of new users of GLP-1RA and SU, between January 2007 and January 2016. Patients with a prior history of depression, self-harm and other serious psychiatric conditions were excluded.

MAIN OUTCOME MEASURES

The primary study outcome comprised a composite of new-onset depression or self-harm. Unadjusted and adjusted Cox proportional hazards regression was used to quantify the association between incretin-based therapies and depression or self-harm. Deciles of High-Dimensional Propensity Scores and concurrent number of glucose-lowering agents were used to adjust for potential confounding.

RESULTS

We identified new users of 6206 DPP-4i and 22 128 SU in the DPP-4i-cohort, and 501 GLP-1RA and 16 409 SU new users in the GLP-1RA-cohort. The incidence of depression or self-harm was 8.2 vs 11.7 events/1000 person-years in the DPP-4i-cohort and 18.2 vs 13.6 events/1000 person-years in the GLP-1RA-cohort for incretin-based therapies versus SU, respectively. Incretin-based therapies were not associated with an increased or decreased incidence of depression or self-harm compared with SU (DPP-4i-cohort: unadjusted HR 0.70, 95% CI 0.51 to 0.96; adjusted HR 0.80, 95% CI 0.57 to 1.13; GLP-1RA-cohort: unadjusted HR 1.36, 95% CI 0.72 to 2.58; adjusted HR 1.25, 95% CI 0.63 to 2.50). Consistent results were observed for other glucose-lowering comparators including insulin and thiazolidinediones.

CONCLUSIONS

Our findings suggest that the two incretin-based therapies are not associated with an increased or decreased risk of depression or self-harm.

Health-Related Quality of Life Assessments with Once-Weekly Glucagon-Like Peptide-1 Receptor Agonists in Type 2 Diabetes Mellitus

Type 2 diabetes (T2DM) is associated with significant impairment in health-related quality of life (HRQoL). A patient-centered collaborative approach is recommended to optimize clinical outcomes, including HRQoL, in this patient population. Glucagon-like peptide-1 receptor agonists (GLP-1 RAs) provide effective glycemic control and have demonstrated beneficial effects on HRQoL and treatment satisfaction. Available once-weekly GLP-1 RAs may offer enhanced convenience compared with daily GLP-1 RAs and include exenatide extended-release (ER), dulaglutide, and semaglutide. This article reviews the impact of once-weekly GLP-1 RAs on HRQoL and treatment satisfaction in patients with T2DM. Compared with oral antihyperglycemic drugs, insulin, and daily GLP-1 RAs, once-weekly GLP-1 RAs offer benefits with regard to HRQoL and treatment satisfaction. These benefits appear to be largely mediated by relative drug effects on glycemic control, weight, and hypoglycemia. While there was not an overall class benefit of once-weekly GLP-1 RAs compared with daily GLP-1 RAs on HRQoL and treatment satisfaction, results suggested that once-weekly GLP-1 RAs may enhance certain elements of treatment satisfaction and increase willingness to continue treatment. In 2 studies comparing once-weekly GLP-1 RAs with each other, semaglutide produced significantly greater improvement in overall treatment satisfaction compared with exenatide ER but not dulaglutide. Once-weekly GLP-1 RAs represent an effective and convenient treatment option that may potentially increase treatment satisfaction and enhance adherence, contributing to improved health outcomes.

DISCLOSURES

This supplement was funded by Novo Nordisk. Billings reports personal fees from Dexcom, Novo Nordisk, and Sanofi. Handelsman reports research grants from Amgen, AstraZeneca, Bristol-Myers Squibb, Boehringer Ingelheim, Grifols, Janssen, Lexicon, Merck, Novo Nordisk, Regeneron, and Sanofi; speaker fees from Amarin, Amgen, AstraZeneca, Boehringer Ingelheim-Lilly, Janssen, Merck, Novo Nordisk, Regeneron, and Sanofi; and has served in advisory capacity to Amarin, Amgen, AstraZeneca, Boehringer Ingelheim, Eisai, Intarcia, Janssen, Lilly, Merck, Merck-Pfizer, Novo Nordisk, Regeneron, and Sanofi. Heile reports speaker fees from and has served as advisor to Novo Nordisk. Schneider reports advisory board fees from Intarcia, Lilly, and Novo Nordisk. Wyne has nothing to disclose.

Satisfaction and efficacy of switching from daily dipeptidyl peptidase-4 inhibitors to weekly trelagliptin in patients with type 2 diabetes-Randomized controlled study

We compared treatment satisfaction between daily dipeptidyl peptidase-4 (DPP-4) inhibitors and a weekly DPP-4 inhibitor in patients with type 2 diabetes. The study was a 12-week, open-label, randomized, multicenter, controlled trial. Participants were Japanese patients with type 2 diabetes who had received daily DPP-4 inhibitors for more than 3 months. Patients were randomly assigned to a treatment cohort: (1) a group that continued taking daily DPP-4 inhibitors (daily group); or (2) a group that switched from daily DPP-4 inhibitors to a weekly DPP-4 inhibitor, trelagliptin (weekly group). The primary outcome was the change in treatment satisfaction levels from baseline to 12 weeks between the two groups, according to Diabetes Treatment Satisfaction Questionnaire (DTSQ) and Diabetes Therapy-Related Quality of Life (DTR-QOL) questionnaire scores. The changes in glycemic control and body weight were also assessed. Of 49 patients initially enrolled in the study, 47 completed the study. The change in DTSQ scores in the weekly group was not significantly different from that in the daily group. However, the improvements in total score and subscale domains 1 and 2 in the DTR-QOL analysis, which relate to burden on social/daily activities and anxiety/dissatisfaction with treatment, were significantly greater in the weekly group than the daily group (p = 0.048, 0.013 and 0.045, respectively). Mean changes in glycated hemoglobin levels and body weight were comparable between the groups. Switching from daily DPP-4 inhibitors to a weekly DPP-4 inhibitor, trelagliptin, could partially improve treatment satisfaction levels in patients with type 2 diabetes without affecting glycemic control.

Improvement of quality of life through glycemic control by liraglutide, a GLP-1 analog, in insulin-naive patients with type 2 diabetes mellitus: the PAGE1 study

BACKGROUND

In addition to achieving good glycemic control, diabetes care management aims to improve the quality of life (QOL) in patients. Treatment-associated difficulties and side effects frequently cause deterioration in QOL. Liraglutide, a GLP-1 receptor agonist, is a novel injection drug that promotes insulin secretion. It is a user-friendly, once-daily injection with fewer hypoglycemic events. In this study, we aimed to examine the effect of liraglutide therapy on QOL in patients.

METHODS

In total, 304 insulin- and liraglutide-naïve patients with type 2 diabetes were enrolled in this observational study; they received liraglutide therapy for 12 weeks. The main outcome measure was change in QOL from baseline, which was assessed using diabetes therapy-related QOL (DTR-QOL).

RESULTS

At week 12, liraglutide significantly decreased HbA1c levels (8.7 ± 1.5 vs. 7.5 ± 1.3, p < 0.001) and BMI (27.9 ± 5.3 vs. 27.3 ± 5.2, p < 0.001). According to the QOL scores, although the treatment modality had changed from non-injection to injection therapy, liraglutide improved patient satisfaction with treatment. Significant correlations were found between change in HbA1c level and satisfaction with treatment, as well as between change in body weight and burden on social and daily activities, anxiety and dissatisfaction with treatment, and hypoglycemia.

CONCLUSIONS

Liraglutide significantly improved glycemic control and reduced the body weight without deteriorating QOL in obese patients with type 2 diabetes. Trial registration UMIN-CTR: UMIN000007159.

Patient Reported Outcomes (PROs) used in recent Phase 3 trials for Type 2 Diabetes: A review of concepts assessed by these PROs and factors to consider when choosing a PRO for future trials

AIMS

Many treatment options are available for people with Type 2 Diabetes (T2D). While the goal of treatment is to reach target HbA1c levels, the psychological experience may be more tangible and meaningful for the patient. Together with biomarkers, Patient-Reported Outcome (PRO) data provide a holistic understanding of the clinical and psychosocial impact of T2D and its treatment.

METHODS

A literature review was conducted in multiple databases to identify PRO endpoints used in Phase 3 trials of newer classes of drugs for the treatment of T2D.

RESULTS

This review identified five PRO concepts which were evaluated as endpoints in Phase 3 trials of GLP-1 receptor agonists, novel insulins, SGLT-2 inhibitors, and DPP-4 inhibitors; symptoms, health-related quality of life, psychological well-being, satisfaction with treatment/health and impact of weight. Twenty PRO questionnaires were used to measure these concepts/endpoints directly from patients. The relevance of, and scientific basis for, these concepts as endpoints are discussed, the similarities and differences between questionnaires targeting the same concepts/endpoints are explored, and the sensitivity of the questionnaires to the experimental intervention is summarized. In addition, factors that should be considered when choosing PROs for future T2D trials are discussed.

CONCLUSIONS

The information gained from PROs in clinical trial research is important in defining treatment benefit within the context of the trial, and the potential benefit (i.e. better adherence) in clinical practice. However, variable results have been observed in recent trials and careful and systematic consideration should be given to PRO selection for future studies of T2D.

Investigating incretin-based therapies as a novel treatment for depression in type 2 diabetes: Findings from the South London Diabetes (SOUL-D) Study

We aimed to investigate the association between incretin-based therapies and 1-year change in depressive symptoms in a cohort of 1735 patients with newly diagnosed type 2 diabetes. The incretin group experienced significant reduction in depressive symptoms compared to controls. This was independent of HbA1c and may be mediated by an anti-inflammatory mechanism.

Therapeutic Options for the Management of Postprandial Glucose in Patients With Type 2 Diabetes on Basal Insulin

In Brief For patients with type 2 diabetes who require add-on therapy to metformin plus basal insulin, GLP-1 receptor agonists may be a favorable option because they effectively manage postprandial glucose, reduce body weight, and have an overall favorable safety profile compared to other agents. Given the wide range of treatment combinations available for type 2 diabetes management, health professionals must partner with patients to determine the best choices based on patients' individual lifestyle, resources, and treatment goals.

Managing recent-onset diabetes: choosing durable, well-tolerated therapies and understanding the role of incretin-based therapies

Management of recent-onset diabetes offers osteopathic physicians the opportunity to work with patients to set treatment goals and expectations for this progressive yet manageable disease, as well as intervene early to reduce the risk of diabetes-related complications. Starting effective therapy early--and intensifying therapy appropriately--to achieve and maintain glycemic goals has been shown to reduce microvascular risks and produce legacy effects that may have macrovascular benefits. Metformin remains a cornerstone of therapy for those patients who can tolerate it. Early combination therapy that is well tolerated reduces risks of hypoglycemia or unwanted weight gain, improves patient adherence, and addresses the multifactoral pathophysiology of even recent-onset diabetes. Incretin-based therapies have been shown to be effective across the spectrum of type 2 diabetes mellitus, including recent-onset diabetes. The present article reviews the use of incretin-based therapies early in the disease process of type 2 diabetes mellitus.

WITHDRAWN: Sulphonylurea monotherapy for patients with type 2 diabetes mellitus

The Cochrane Metabolic and Endocrine Disorders Group withdrew this review as of Issue 7, 2015 because of the involvement of one author (SS Lund) being employed in a pharmaceutical company. The authors of the review and the Cochrane Metabolic and Endocrine Disorders Group did not find that this was a breach of the rules of the Cochrane Collaboration at the time when it was published. However, after the publication of the review, the Cochrane Collaboration requested withdrawal of the review due to the employment of the author. A new protocol for a review to cover this topic will be published. This will have a new title and a markedly improved protocol fulfilling new and important developments and standards within the Cochrane Collaboration as well as an improved inclusion and search strategy making it necessary to embark on a completely new review project.

The editorial group responsible for this previously published document have withdrawn it from publication.

Type 2 diabetes mellitus

Type 2 diabetes mellitus (T2DM) is an expanding global health problem, closely linked to the epidemic of obesity. Individuals with T2DM are at high risk for both microvascular complications (including retinopathy, nephropathy and neuropathy) and macrovascular complications (such as cardiovascular comorbidities), owing to hyperglycaemia and individual components of the insulin resistance (metabolic) syndrome. Environmental factors (for example, obesity, an unhealthy diet and physical inactivity) and genetic factors contribute to the multiple pathophysiological disturbances that are responsible for impaired glucose homeostasis in T2DM. Insulin resistance and impaired insulin secretion remain the core defects in T2DM, but at least six other pathophysiological abnormalities contribute to the dysregulation of glucose metabolism. The multiple pathogenetic disturbances present in T2DM dictate that multiple antidiabetic agents, used in combination, will be required to maintain normoglycaemia. The treatment must not only be effective and safe but also improve the quality of life. Several novel medications are in development, but the greatest need is for agents that enhance insulin sensitivity, halt the progressive pancreatic β-cell failure that is characteristic of T2DM and prevent or reverse the microvascular complications. For an illustrated summary of this Primer, visit: http://go.nature.com/V2eGfN.

Add-On Treatment with Liraglutide Improves Glycemic Control in Patients with Type 2 Diabetes on Metformin Therapy

BACKGROUND

Liraglutide is a glucagon-like peptide-1 receptor analog recently approved for the treatment of type 2 diabetes mellitus (T2DM). We aimed to assess the efficacy and safety of liraglutide versus glimepiride, as adjunct treatments to metformin, in achieving glycemic control in Italian patients with T2DM uncontrolled by metformin alone.

SUBJECTS AND METHODS

One hundred seventy-nine diabetes patients treated with metformin plus liraglutide (1.8 mg) or glimepiride (4 mg) were retrospectively assessed at baseline, during, and after 18 months of continuous therapy.

RESULTS

Treatment with liraglutide resulted in mean decreases in hemoglobin A1c (HbA1c) of -1.4%, when compared with glimepiride (-0.4%) (P < 0.001), and was followed by a significant reduction (P < 0.001) in fasting plasma glucose. Variations in HbA1c occurred independently from weight loss, which was significantly reduced (P < 0.001) in liraglutide-treated patients. The percentage of subjects reaching HbA1c levels below 7% or ≤ 6.5% was significantly different between the two treated groups (P < 0.001). Treatment with liraglutide reduced waist circumference (WC) (P < 0.001) and decreased both systolic and diastolic blood pressure (BP) (P < 0.001). It is interesting that the study also showed the impact of female gender in predicting a better glycemic response to liraglutide (P = 0.028).

CONCLUSIONS

Liraglutide was more effective than glimepiride in reducing HbA1c levels in treated patients with T2DM. This was evident in both genders, but particularly in women. Furthermore, liraglutide reduced body weight, WC, and BP, which are critical risk factors for cardiovascular disease.

Safety and tolerability of exenatide once weekly in patients with type 2 diabetes: an integrated analysis of 4,328 patients

BACKGROUND

Exenatide once weekly (QW) is a glucagon-like peptide-1 receptor agonist (GLP-1RA) for the treatment of type 2 diabetes. Safety and tolerability are key considerations in treatment selection. This analysis examines the safety and tolerability profile of exenatide QW, other approved GLP-1RAs (exenatide twice daily and liraglutide once daily), and a pooled population of commonly used non-GLP-1RA treatments.

METHODS

Intent-to-treat populations from eight randomized Phase III trials with 24-week and 30-week comparator-controlled periods were analyzed. Data were pooled for exenatide QW, exenatide twice daily, and non-GLP-1RA comparator groups; comparisons between exenatide QW and liraglutide were analyzed separately to better match study groups. The incidence of treatment-emergent adverse events with 95% confidence intervals and exposure-adjusted incidence were calculated. Duration and recurrence were analyzed for gastrointestinal adverse events and adverse events of special interest.

RESULTS

Incidences of serious adverse events did not differ between treatments. Discontinuations due to adverse events occurred numerically less frequently with exenatide QW than with other GLP-1RAs but numerically more frequently than with non-GLP-1RA comparators. The most frequent adverse events in the GLP-1RA groups were gastrointestinal and generally mild, with decreasing incidence over time. Gastrointestinal adverse event incidences appeared lower with exenatide QW versus other GLP-1RAs and greater than with non-GLP-1RA comparators. Injection site-related adverse events seemed highest with exenatide QW, but generally did not lead to withdrawal and abated over time. Hypoglycemia was infrequent overall, but occurred numerically more frequently in the non-GLP-1RA comparator group and increased with concomitant sulfonylurea use. Pancreatitis, thyroid cancer, renal failure, and gallbladder disease were rarely reported.

CONCLUSION

The overall safety and tolerability profile of exenatide QW was similar to that of other GLP-1RAs, with improved gastrointestinal tolerability. The safety and tolerability profile of exenatide QW compared with non-GLP-1RA comparators was similar overall, with the exception of a lower incidence of hypoglycemia and anticipated differences in gastrointestinal and injection site-related adverse events.

Review of patient-reported outcome instruments measuring health-related quality of life and satisfaction in patients with type 2 diabetes treated with oral therapy

OBJECTIVE

Treatments and their mode of administration may represent a burden for patients and can therefore impact their health-related quality of life (HRQL) or treatment/health satisfaction. Patients with type 2 diabetes mellitus (T2DM) can be treated with oral hypoglycemic agents (OHAs), injectable medications (such as insulin), or a combination of agents. This review aimed to identify patient-reported outcome (PRO) instruments measuring HRQL and/or satisfaction that could differentiate between oral medications based on medication related attributes such as efficacy, tolerability, weight loss, dosing frequency and pill burden.

RESEARCH DESIGN AND METHODS

Medline, Embase, PsycINFO, Cochrane Library and the Patient-Reported Outcome and Quality of Life Questionnaires (PROQOLID) biomedical databases were searched to identify instruments and document their development methodology, content and psychometric properties (i.e. validity, reliability), responsiveness and ability to detect changes between treatments.

RESULTS

Nineteen instruments were retained based on their potential to differentiate between OHAs. Ten instruments assessed HRQL, amongst which the Audit of Diabetes Dependent Quality of Life, Diabetes 39, Diabetes Health Profile and Impact of Weight on Quality of Life displayed good psychometric properties in T2DM populations and comprehensive HRQL content. Nine instruments assessed satisfaction. Both the Oral Hypoglycemic Agent Questionnaire (OHAQ) and Diabetes Medication Satisfaction (DiabMedSat) Questionnaire have highly relevant content regarding drug attributes. The OHAQ is specific to oral treatment and the DiabMedSat includes HRQL items. The Diabetes Treatment Satisfaction Questionnaire is a standard instrument that is extensively used and provides conclusive results in studies of patients with T2DM.

CONCLUSIONS

Very few of the existing PRO instruments are specific to OHAs. Despite satisfaction instruments being recommended to differentiate between OHAs in studies of T2DM based on medication attributes, we find that none of the existing instruments appear to be useful in detecting differences between treatments, therefore limiting their use in clinical and observational research.

Liraglutide reduces the body weight and waist circumference in Chinese overweight and obese type 2 diabetic patients

AIM

To investigate the effects of liraglutide, a glucagon-like peptide-1 (GLP-1) receptor activator, on body weight and waist circumference in Chinese overweight and obese type 2 diabetic patients.

METHODS

A total of 328 Chinese overweight and obese type 2 diabetic patients were included in this multi-center, open-labeled and self-controlled clinical study. The patients were subcutaneously injected with liraglutide once daily for 24 weeks as add-on therapy to their previous hypoglycemic treatments. Statistical analyses were performed using SPSS software package version 11.5 for Windows.

RESULTS

Liraglutide treatment caused significant reduction of the mean body weight (from 86.61±14.09 to 79.10±13.55 kg) and waist circumference (from 101.81±13.96 to 94.29±14.17 cm), resulting in body weight lose of 5%-10% in 43.67% patients, and body weight loss above 10% in 34.06% patients, who had significant lower plasma creatinine levels. Baseline waist circumference, BMI and HOMA-IR were independently correlated with the body weight loss. Furthermore, liraglutide treatment significantly decreased HbA1c levels (from 8.66%±2.17% to 6.92%±0.95%) with HbA1c<7.0% in 35.37% patients, who had a significantly lower baseline level of HbA1c, but higher baseline levels of C peptide and glucagon. Moreover, liraglutide treatment resulted in greater body weight loss in patients with a long duration of diabetes, and better glycemic control in patients with a short duration of diabetes.

CONCLUSION

Liraglutide significantly reduces body weight and waist circumference in Chinese overweight and obese type 2 diabetic patients. Patients with apparent visceral obesity, insulin resistance and a long duration of diabetes may have greater body weight loss; whereas patients with high insulin-secreting ability, hyperglucagonemia, and short-duration diabetes may obtain better glycemic control with liraglutide.

A Duplexed High-Throughput Screen to Identify Allosteric Modulators of the Glucagon-Like Peptide 1 and Glucagon Receptors

Injectable, degradation-resistant peptide agonists for the glucagon-like peptide 1 (GLP-1) receptor (GLP-1R), such as exenatide and liraglutide, activate the GLP-1R via a complex orthosteric-binding site and are effective therapeutics for glycemic control in type 2 diabetes. Orally bioavailable orthosteric small-molecule agonists are unlikely to be developed, whereas positive allosteric modulators (PAMs) may offer an improved therapeutic profile. We hypothesize that allosteric modulators of the GLP-1R would increase the potency and efficacy of native GLP-1 in a spatial and temporally preserved manner and/or may improve efficacy or side effects of injectable analogs. We report the design, optimization, and initial results of a duplexed high-throughput screen in which cell lines overexpressing either the GLP-1R or the glucagon receptor were coplated, loaded with a calcium-sensitive dye, and probed in a three-phase assay to identify agonists, antagonists, and potentiators of GLP-1, and potentiators of glucagon. 175,000 compounds were initially screened, and progression through secondary assays yielded 98 compounds with a variety of activities at the GLP-1R. Here, we describe five compounds possessing different patterns of modulation of the GLP-1R. These data uncover PAMs that may offer a drug-development pathway to enhancing in vivo efficacy of both endogenous GLP-1 and peptide analogs.

Preliminary study characterizing the use of sitagliptin for glycemic control in healthy Beagle dogs with normal gluco-homeostasis

Sitagliptin is a dipeptidyl peptidase-4 inhibitor aimed at treating Type 2 diabetes mellitus (T2DM) and T1DM, by increasing blood levels of Glucagon-like peptide 1 (GLP-1) and insulin. The objective of this preliminary study is to characterize Sitagliptin’s ability for glycemic control, in healthy dogs under an oral glucose tolerance test (OGTT) environment. Overall, Sitagliptin did not result in any significant changes to temporal glucose and insulin concentrations. However, a ~55% increase in median total GLP-1 AUC_0–120min was observed, as compared to baseline control in healthy dogs (n=5), thus indicating a similar mode of action of Sitagliptin between healthy dogs and humans. Future studies to validate the use of Sitagliptin with dogs suffering from insulin independent diabetes are warranted.

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

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

Comparative effectiveness of liraglutide in the treatment of type 2 diabetes

Type 2 diabetes is characterized by a progressive decline in beta cell function, with consequent worsening of glycemic control. The ideal antihyperglycemic treatment should achieve good and sustained glycemic control, with a low risk of hypoglycemia and no weight gain. This paper reviews the efficacy and tolerability of liraglutide, a glucagon-like peptide-1 receptor agonist approved for the treatment of type 2 diabetes. Once-daily injection of liraglutide (at doses of 1.2 mg and 1.8 mg), as monotherapy or in combination with one or two oral antihyperglycemic agents, was associated with greater improvements in glycemic control compared with active comparators or placebo in several controlled, randomized Phase III trials, including the six trials of the LEAD (Liraglutide Effect and Action in Diabetes) program. Liraglutide also improved beta cell function, body weight, systolic blood pressure, and lipid profile, thereby achieving many of the goals of ideal antihyperglycemic therapy. Liraglutide was generally well tolerated in the Phase III trials. The most common adverse events were nausea, vomiting, and diarrhea, usually of mild to moderate intensity. The observed rate of pancreatitis was low and comparable with that of the general diabetic population. In conclusion, although most trials were relatively short and focused on surrogate endpoints, liraglutide emerges as an effective and well tolerated treatment for type 2 diabetes, carrying a low risk of hypoglycemia, weight loss, and possible reduction of cardiovascular risk.

Breaking down patient and physician barriers to optimize glycemic control in type 2 diabetes

Approximately half of patients with type 2 diabetes (T2D) do not achieve globally recognized blood glucose targets, despite the availability of a wide range of effective glucose-lowering therapies. Failure to maintain good glycemic control increases the risk of diabetes-related complications and long-term health care costs. Patients must be brought under glycemic control to improve treatment outcomes, but existing barriers to optimizing glycemic control must first be overcome, including patient nonadherence to treatment, the failure of physicians to intensify therapy in a timely manner, and inadequacies in the health care system itself. The reasons for such barriers include treatment side effects, complex treatment regimens, needle anxiety, poor patient education, and the absence of an adequate patient care plan; however, newer therapies and devices, combined with comprehensive care plans involving adequate patient education, can help to minimize barriers and improve treatment outcomes.

Current issues in GLP-1 receptor agonist therapy for type 2 diabetes

The clinical management of hyperglycemia in patients with type 2 diabetes mellitus (T2DM) is guided not only by published treatment algorithms, but also by consideration of recent evidence and through consultation with colleagues and experts. Recent studies have dramatically increased the amount of information regarding the use of glucagon-like peptide-1 receptor agonists (GLP-1 RAs). Topics that may be of particular interest to clinicians who treat T2DM patients include relative glycemic control efficacy of GLP-1 RAs, use of GLP-1 RAs across T2DM progression and in combination with insulin, recent data regarding GLP-1 RA safety, nonglycemic actions of GLP-1 RAs, including weight effects, and impact of GLP-1 RAs on patient quality of life and treatment satisfaction. The following review includes expert consideration of these topics with emphasis on recent, relevant reports to illustrate current perspectives.

Sulphonylurea monotherapy for patients with type 2 diabetes mellitus

BACKGROUND

Type 2 diabetes mellitus (T2DM) is a growing health problem worldwide. Whether sulphonylureas show better, equal or worse therapeutic effects in comparison with other antidiabetic interventions for patients with T2DM remains controversial.

OBJECTIVES

To assess the effects of sulphonylurea monotherapy versus placebo, no intervention or other antidiabetic interventions for patients with T2DM.

SEARCH METHODS

We searched publications in The Cochrane Library, MEDLINE, EMBASE, Science Citation Index Expanded, LILACS and CINAHL (all until August 2011) to obtain trials fulfilling the inclusion criteria for our review.

SELECTION CRITERIA

We included clinical trials that randomised patients 18 years old or more with T2DM to sulphonylurea monotherapy with a duration of 24 weeks or more.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed the risk of bias. The primary outcomes were all-cause and cardiovascular mortality. Secondary outcomes were other patient-important outcomes and metabolic variables. Where possible, we used risk ratios (RR) with 95% confidence intervals (95% CI) to analyse the treatment effect of dichotomous outcomes. We used mean differences with 95% CI to analyse the treatment effect of continuous outcomes. We evaluated the risk of bias. We conducted trial sequential analyses to assess whether firm evidence could be established for a 10% relative risk reduction (RRR) between intervention groups.

MAIN RESULTS

We included 72 randomised controlled trials (RCTs) with 22,589 participants; 9707 participants randomised to sulphonylureas versus 12,805 participants randomised to control interventions. The duration of the interventions varied from 24 weeks to 10.7 years. We judged none of the included trials as low risk of bias for all bias domains. Patient-important outcomes were seldom reported.First-generation sulphonylureas (FGS) versus placebo or insulin did not show statistical significance for all-cause mortality (versus placebo: RR 1.46, 95% CI 0.87 to 2.45; P = 0.15; 2 trials; 553 participants; high risk of bias (HRB); versus insulin: RR 1.18, 95% CI 0.88 to 1.59; P = 0.26; 2 trials; 1944 participants; HRB). FGS versus placebo showed statistical significance for cardiovascular mortality in favour of placebo (RR 2.63, 95% CI 1.32 to 5.22; P = 0.006; 2 trials; 553 participants; HRB). FGS versus insulin did not show statistical significance for cardiovascular mortality (RR 1.36, 95% CI 0.68 to 2.71; P = 0.39; 2 trials; 1944 participants; HRB). FGS versus alpha-glucosidase inhibitors showed statistical significance in favour of FGS for adverse events (RR 0.63, 95% CI 0.52 to 0.76; P = 0.01; 2 trials; 246 participants; HRB) and for drop-outs due to adverse events (RR 0.28, 95% CI 0.12 to 0.67; P = 0.004; 2 trials; 246 participants; HRB).Second-generation sulphonylureas (SGS) versus metformin (RR 0.98, 95% CI 0.61 to 1.58; P = 0.68; 6 trials; 3528 participants; HRB), thiazolidinediones (RR 0.92, 95% CI 0.60 to 1.41; P = 0.70; 7 trials; 4955 participants; HRB), insulin (RR 0.96, 95% CI 0.79 to 1.18; P = 0.72; 4 trials; 1642 participants; HRB), meglitinides (RR 1.44, 95% CI 0.47 to 4.42; P = 0.52; 7 trials; 2038 participants; HRB), or incretin-based interventions (RR 1.39, 95% CI 0.52 to 3.68; P = 0.51; 2 trials; 1503 participants; HRB) showed no statistically significant effects regarding all-cause mortality in a random-effects model. SGS versus metformin (RR 1.47; 95% CI 0.54 to 4.01; P = 0.45; 6 trials; 3528 participants; HRB), thiazolidinediones (RR 1.30, 95% CI 0.55 to 3.07; P = 0.55; 7 trials; 4955 participants; HRB), insulin (RR 0.96, 95% CI 0.73 to 1.28; P = 0.80; 4 trials; 1642 participants; HRB) or meglitinide (RR 0.97, 95% CI 0.27 to 3.53; P = 0.97; 7 trials, 2038 participants, HRB) showed no statistically significant effects regarding cardiovascular mortality. Mortality data for the SGS versus placebo were sparse. SGS versus thiazolidinediones and meglitinides did not show statistically significant differences for a composite of non-fatal macrovascular outcomes. SGS versus metformin showed statistical significance in favour of SGS for a composite of non-fatal macrovascular outcomes (RR 0.67, 95% CI 0.48 to 0.93; P = 0.02; 3018 participants; 3 trials; HRB). The definition of non-fatal macrovascular outcomes varied among the trials. SGS versus metformin, thiazolidinediones and meglitinides showed no statistical significance for non-fatal myocardial infarction. No meta-analyses could be performed for microvascular outcomes. SGS versus placebo, metformin, thiazolidinediones, alpha-glucosidase inhibitors or meglitinides showed no statistical significance for adverse events. SGS versus alpha-glucosidase inhibitors showed statistical significance in favour of SGS for drop-outs due to adverse events (RR 0.48, 95% CI 0.24 to 0.96; P = 0.04; 9 trials; 870 participants; HRB). SGS versus meglitinides showed no statistical significance for the risk of severe hypoglycaemia. SGS versus metformin and thiazolidinediones showed statistical significance in favour of metformin (RR 5.64, 95% CI 1.22 to 26.00; P = 0.03; 4 trials; 3637 participants; HRB) and thiazolidinediones (RR 6.11, 95% CI 1.57 to 23.79; P = 0.009; 6 trials; 5660 participants; HRB) for severe hypoglycaemia.Third-generation sulphonylureas (TGS) could not be included in any meta-analysis of all-cause mortality, cardiovascular mortality or non-fatal macro- or microvascular outcomes. TGS versus thiazolidinediones showed statistical significance regarding adverse events in favour of TGS (RR 0.88, 95% CI 0.78 to 0.99; P = 0.03; 3 trials; 510 participants; HRB). TGS versus thiazolidinediones did not show any statistical significance for drop-outs due to adverse events. TGS versus other comparators could not be performed due to lack of data.For the comparison of SGS versus FGS no meta-analyses of all-cause mortality, cardiovascular mortality, non-fatal macro- or microvascular outcomes, or adverse events could be performed.Health-related quality of life and costs of intervention could not be meta-analysed due to lack of data.In trial sequential analysis, none of the analyses of mortality outcomes, vascular outcomes or severe hypoglycaemia met the criteria for firm evidence of a RRR of 10% between interventions.

AUTHORS' CONCLUSIONS

There is insufficient evidence from RCTs to support the decision as to whether to initiate sulphonylurea monotherapy. Data on patient-important outcomes are lacking. Therefore, large-scale and long-term randomised clinical trials with low risk of bias, focusing on patient-important outcomes are required.

Characterization of the use of liraglutide for glycemic control in healthy and Type 1 diabetes mellitus suffering dogs

Glucagon-like peptide 1 (GLP-1) is a glucose-lowering, intestinal-derived factor with multiple physiological effects, making it attractive for diabetes therapy. However, the therapeutic potential of endogenous GLP-1 is limited, because of rapid inactivation by dipeptidyl peptidase-4. Recently, enhanced incretin preparations, such as liraglutide, have emerged, which are more resistant to degradation and longer lasting. Liraglutide is a long-acting acylated human GLP-1 receptor agonist, with a 97% amino acid sequence identity to endogenous human GLP-1, and 100% amino acid sequence homology with canine GLP-1. Since liraglutide has yet to be examined for use in dogs, and the incretin effect has been reported to exist in dogs, we sought to initially characterize liraglutide's ability for glycemic control in healthy dogs, under an oral glucose tolerance test (OGTT) environment initially. This was followed up a more realistic scenario involving food with insulin injection +/- liraglutide injection resulting in a glucose curve based study involving dogs suffering from Type 1 diabetes mellitus (T1DM). Overall, liraglutide had a stabilizing effect on glucose levels, maintaining circulating levels between 77.0 and 137.0mg/ml throughout the OGTT test period, resulting in a significant reduction of 13.8% in glucose AUC0-120 min (total area under the curve for 0-120 min) as compared to baseline control in healthy dogs (n=5). Interestingly, the liraglutide associated reduction in circulating glucose was not accompanied by any significant increase in insulin. Moreover, T1DM dogs (n=4) responded favorably to liraglutide treatment, which lead to a significant reduction of 46.0% in glucose AUC0-12h (total area under the curve for 0-12h), and a significant reduction of 66.5% in serum glucose as compared to baseline controls (insulin treatment only). Therefore, liraglutide's prandial glucagon suppressive ability appears to play a key role in its glucose-lowering capability, and offers great potential for use with dogs suffering from T1DM.

Insulin: standard therapy following oral hypoglycaemic failure in type 2 diabetes?

The cost burden of managing type 2 diabetes and its complications could overwhelm the NHS in the next 20 years. The available therapies should be used wisely to conserve resource and maintain health. This article outlines a strategy for use of the available treatments.

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.

Facilitating healthy coping in patients with diabetes: a systematic review

PURPOSE

The purpose of this study is to summarize recent literature on approaches to supporting healthy coping in diabetes in 2 specific areas: (1) the impact of different approaches to diabetes treatment on healthy coping and (2) the effectiveness of interventions specifically designed to support healthy coping.

METHODS

A PubMed search identified 129 articles published August 1, 2006, to April 30, 2011, addressing diabetes in relation to emotion, quality of life, depression, adjustment, anxiety, coping, family therapy, behavior therapy, psychotherapy, problem solving, couples therapy, or marital therapy.

RESULTS

Evidence suggests that treatment choice may significantly influence quality of life, with treatment intensification in response to poor metabolic control often improving quality of life. The recent literature provides support for a variety of healthy coping interventions in diverse populations, including diabetes self-management education, support groups, problem-solving approaches, and coping skills interventions for improving a range of outcomes; cognitive behavior therapy and collaborative care for treating depression; and family therapy for improving coping in youths.

CONCLUSIONS

Healthy coping in diabetes has received substantial attention in the past 5 years. A variety of approaches show positive results. Research is needed to compare the effectiveness of different approaches in different populations and determine how to overcome barriers to intervention dissemination and implementation.

Patient-reported outcomes in trials of incretin-based therapies in patients with type 2 diabetes mellitus

Incretin-based therapies have a glucose-dependent mode of action that results in excellent glucose-lowering efficacy with very low risk of hypoglycaemia, and weight neutrality [dipeptidyl peptidase-4 (DPP-4) inhibitors] or weight loss [glucagon-like peptide-1 (GLP-1) receptor agonists], in people with type 2 diabetes mellitus (T2DM). Patient-reported outcomes (PROs) complement physician evaluations of efficacy and tolerability and offer insights into the subjective experience of using modern diabetes treatments. We conducted a systematic search of clinical trials of the GLP-1 receptor agonists liraglutide, exenatide and long-acting exenatide, one of which included the oral DPP-4 inhibitor sitagliptin as a comparator. No other PRO data for DPP-4 inhibitors were identified. This review summarizes PRO data from eight clinical trials, the majority of which used the Diabetes Treatment Satisfaction Questionnaire (DTSQ) and/or Impact of Weight on Quality of Life-Lite (IWQOL-Lite) to evaluate patient experience. People with T2DM were highly satisfied with modern incretin-based therapies compared with traditional therapies. Treatment satisfaction (including perceptions of convenience and flexibility) was high and generally higher with GLP-1 agonists in association with their greater glucose-lowering efficacy and tendency to facilitate weight loss. Weight-related quality of life (QoL) also improved in people using incretin therapies. The glycaemic improvements achieved with GLP-1 receptor agonists, coupled with the low incidence of hypoglycaemia and ability to cause weight loss, seemed to offset potential concern about injections. It is plausible that superior patient-reported benefits found in clinical trials may translate into improved, clinically meaningful, long-term outcomes through increased treatment acceptability. Long-term, prospective data are needed to ascertain whether this is the case in practice.

Liraglutide: a review of its use in the management of type 2 diabetes mellitus

Liraglutide (Victoza®) is a subcutaneously administered glucagon-like peptide-1 (GLP-1) receptor agonist produced by recombinant DNA technology and used as an adjunct to diet and exercise in the treatment of adults with type 2 diabetes mellitus. This article reviews the clinical efficacy and tolerability of liraglutide in adults with type 2 diabetes, and provides a summary of its pharmacological properties. Recently published pharmacoeconomic studies of liraglutide are also reviewed. Administered subcutaneously, liraglutide (usually 1.2 or 1.8 mg once daily) generally produced greater improvements in glycaemic control than active comparators or placebo when administered as monotherapy or in combination with one or two oral antidiabetic drugs (OADs) to adults with type 2 diabetes in numerous randomized, controlled phase III trials. These included six trials in the LEAD trial programme that was designed to evaluate the efficacy and safety of liraglutide across a continuum of antihyperglycaemic management for patients with type 2 diabetes. Liraglutide was generally well tolerated, with a low risk of hypoglycaemia evident, in the phase III trials. The most common adverse events were gastrointestinal and included nausea and diarrhoea; most events were mild to moderate in severity and decreased in incidence over time. In conclusion, liraglutide has an important place in the management of adults with type 2 diabetes across a continuum of care. As well as providing effective glycaemic control, liraglutide improves pancreatic β-cell function and leads to bodyweight loss, thereby addressing some of the unmet needs of patients treated with traditional OADs.

The role of GLP-1 mimetics and basal insulin analogues in type 2 diabetes mellitus: guidance from studies of liraglutide

In people with type 2 diabetes mellitus (T2DM), the incretin effect is reduced, but the recent advent of dipeptidyl peptidase-4 inhibitors and glucagon-like peptide (GLP)-1 agonists/analogues has enabled restoration of at least some of the function of the incretin system, with accompanying improvements in glycaemic control. Two GLP-1 receptor agonists/analogues are currently approved for the treatment of T2DM-exenatide (Byetta®, Eli Lilly & Co., Indianapolis, IN, US) and liraglutide (Victoza®, Novo Nordisk, Bagsvaerd, Denmark); a once-weekly formulation of exenatide (Bydureon®, Eli Lilly & Co.) has also been approved by the European Medicines Agency. The National Institute for Health and Clinical Excellence (NICE) has recently published guidance on the use of liraglutide in T2DM, based on evidence from the Liraglutide Effect and Action in Diabetes (LEAD) Phase III trial programme, which compared liraglutide with existing glucose-lowering therapies, such as exenatide and insulin glargine. The LEAD programme reported HbA1c reductions from 0.8 to 1.5% with liraglutide (1.2 and 1.8 mg), accompanied by low rates of hypoglycaemia and some weight loss; side effects were primarily gastrointestinal in nature (e.g. nausea and diarrhoea). Based on the findings of the LEAD studies and the NICE recommendation, liraglutide now represents an important therapy widely available in the UK for certain patient groups, including those with a body mass index (BMI) ≥35.0 kg/m(2) , and patients with a BMI <35 kg/m(2) who are considered unsuitable for insulin and are failing to meet targets for glycaemic control with oral agents. NICE guidelines still suggest that most patients without considerable obesity (BMI <35 kg/m(2) ) are probably best managed using insulin therapy. Evidence also suggests a future role for GLP-1 mimetics in combination with basal insulin.

Novel GLP-1 receptor agonists for diabetes

INTRODUCTION

GLP-1 receptor agonists have been shown to be effective in the treatment of type 2 diabetes mellitus (T2DM). Although the first GLP-1 receptor agonist, exenatide, was approved in the mid-2000s, other agents with longer durations of action (that do not require twice-daily dosing) are now being developed. Indeed, liraglutide, a once-daily GLP-1 receptor agonist, was approved in 2010, and more recently, a once-weekly formulation of exenatide was approved in 2011. This review considers the mechanism of action of GLP-1 receptor agonists and considers the various agents in this class.

AREAS COVERED

The importance of GLP-1 itself in glycemic control and the use of GLP-1 receptor agonists in T2DM are discussed. An overview of the clinical development of the five GLP-1 receptor agonists (exenatide, liraglutide, lixisenatide, albiglutide and taspoglutide) since 2005 is provided and their mechanisms of action, efficacy in terms of glycemic control and weight loss, and tolerability are reviewed.

EXPERT OPINION

GLP-1 receptor agonists result in clinically meaningful weight loss in addition to their beneficial effects on glucose homeostasis. These agents provide substantial clinical benefits for patients compared with sulfonylureas or DPP-4 inhibitors and will, therefore, become one of the major therapeutic choices for patients with T2DM.

Next-generation GLP-1 therapy: an introduction to liraglutide

Liraglutide, a once-daily human glucagon-like peptide-1 (GLP-1) analog, was approved by the US Food and Drug Administration in 2010 for the treatment of type 2 diabetes mellitus (T2DM). Glucagon-like peptide-1 enhances insulin secretion and inhibits glucagon in a glucose-dependent manner. The efficacy and safety of liraglutide were evaluated in 6 phase 3 trials in > 4000 patients in the Liraglutide Effect and Action in Diabetes (LEAD) program, in another trial in comparison with sitagliptin, and in another trial where basal insulin was added to liraglutide + metformin. At liraglutide doses of 1.2 mg or 1.8 mg once daily, significant mean reductions in glycated hemoglobin (HbA1c) (1%-1.6%) and fasting plasma glucose (15-43 mg/dL), as well as sustained weight loss (2-3 kg) and a low rate of hypoglycemia occurred. Mild and transient nausea, reported in 6% to 41% of patients, was the most frequent adverse event reported. Incretin-based therapies such as liraglutide provide an important expansion of options for the treatment of T2DM.

Glucagon-like peptide analogues for type 2 diabetes mellitus

BACKGROUND

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

OBJECTIVES

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

SEARCH STRATEGY

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

SELECTION CRITERIA

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

DATA COLLECTION AND ANALYSIS

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

MAIN RESULTS

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

AUTHORS' CONCLUSIONS

GLP-1 agonists are effective in improving glycaemic control.