Effects of liraglutide (NN2211), a long-acting GLP-1 analogue, on glycaemic control and bodyweight in subjects with Type 2 diabetes

The Real-World Observational Prospective Study of Health Outcomes with Dulaglutide and Liraglutide in Type 2 Diabetes Patients (TROPHIES): Final patient-reported outcomes at 24 months

AIM

To report health-related patient-reported outcomes (PROs) in people with type 2 diabetes (T2D) initiating their first injectable glucose-lowering medication (GLM) with two commonly prescribed glucagon-like peptide-1 receptor agonists (GLP-1RAs) from the prospective, observational TROPHIES study (The Real-World Observational Prospective Study of Health Outcomes with Dulaglutide and Liraglutide in Type 2 Diabetes Patients).

MATERIALS AND METHODS

TROPHIES was a two-cohort, 24-month study conducted in France, Germany and Italy. Adults with a T2D diagnosis, naïve to injectable treatment for T2D and prescribed dulaglutide or liraglutide as their first injectable GLM, were eligible for inclusion. Study objectives included describing the following PROs associated with the treatment of T2D with GLP-1RAs: health-related quality of life; impact of weight on self-perception; life and work productivity; and patient satisfaction with treatment and injection device. Additional analyses formally compared PRO measures between the treatment cohorts.

RESULTS

Overall, improvements from baseline in PRO scores were observed among people who started dulaglutide or liraglutide. A more pronounced trend of improvement was observed in the dulaglutide cohort for changes from baseline in treatment satisfaction and impact of weight on self-perception, supported by statistically significant differences between treatment cohorts in additional comparative analyses at 12, 18 and 24 months. More positive patient perceptions of the injection device were observed with dulaglutide than with liraglutide.

CONCLUSIONS

Improvements in PROs observed in TROPHIES, which were more evident with dulaglutide than liraglutide, reflect a relevant clinical benefit. From the patients' perspective, satisfaction, and confidence in continuing treatment with GLP-1RAs is likely to contribute to long-term treatment persistence.

Incretin hormones and type 2 diabetes

Incretin hormones (glucose-dependent insulinotropic polypeptide [GIP] and glucagon-like peptide-1 [GLP-1]) play a role in the pathophysiology of type 2 diabetes. Along with their derivatives they have shown therapeutic success in type 2 diabetes, with the potential for further improvements in glycaemic, cardiorenal and body weight-related outcomes. In type 2 diabetes, the incretin effect (greater insulin secretory response after oral glucose than with 'isoglycaemic' i.v. glucose, i.e. with an identical glycaemic stimulus) is markedly reduced or absent. This appears to be because of a reduced ability of GIP to stimulate insulin secretion, related either to an overall impairment of beta cell function or to specific defects in the GIP signalling pathway. It is likely that a reduced incretin effect impacts on postprandial glycaemic excursions and, thus, may play a role in the deterioration of glycaemic control. In contrast, the insulinotropic potency of GLP-1 appears to be much less impaired, such that exogenous GLP-1 can stimulate insulin secretion, suppress glucagon secretion and reduce plasma glucose concentrations in the fasting and postprandial states. This has led to the development of incretin-based glucose-lowering medications (selective GLP-1 receptor agonists or, more recently, co-agonists, e.g. that stimulate GIP and GLP-1 receptors). Tirzepatide (a GIP/GLP-1 receptor co-agonist), for example, reduces HbA1c and body weight in individuals with type 2 diabetes more effectively than selective GLP-1 receptor agonists (e.g. semaglutide). The mechanisms by which GIP receptor agonism may contribute to better glycaemic control and weight loss after long-term exposure to tirzepatide are a matter of active research and may change the pessimistic view that developed after the disappointing lack of insulinotropic activity in people with type 2 diabetes when exposed to GIP in short-term experiments. Future medications that stimulate incretin hormone and other receptors simultaneously may have the potential to further increase the ability to control plasma glucose concentrations and induce weight loss.

Efficacy and safety of polyethylene glycol loxenatide as add-on to metformin in patients with type 2 diabetes: A multicentre, randomized, double-blind, placebo-controlled, phase 3b trial

AIM

To assess the efficacy and safety of polyethylene glycol loxenatide (PEX168), a new glucagon-like peptide-1 receptor agonist, as an add-on to metformin therapy in Chinese patients with type 2 diabetes (T2D).

MATERIALS AND METHODS

This was a multicentre, randomized, double-blind, placebo-controlled phase 3b trial. After metformin monotherapy (≥1500 mg/day) for 8 weeks or more, patients with uncontrolled T2D (HbA1c of 7.0%-10.5%) from 44 sites were randomized (1:1:1) to metformin + placebo, metformin + PEX168 100 μg, and metformin + PEX168 200 μg. The core treatment period lasted for 24 weeks, followed by a 28-week extension period. The primary endpoint was the change in HbA1c levels at week 24. The main secondary endpoint was the proportion of patients with an HbA1c of less than 7.0% at week 24.

RESULTS

The least-square mean (standard error) change in HbA1c levels was significantly greater (P < .001 for superiority) in the PEX168 groups (-1.16% [0.08%] and -1.14% [0.08%] with 100 and 200 μg, respectively) than in the placebo group (0.35% [0.08%]). The proportion of patients with an HbA1c of less than 7.0% at week 24 was significantly higher in the PEX168 100 μg (37.4%) and PEX168 200 μg (40.6%) groups than in the placebo group (16.8%; both P < .001). The gastrointestinal reactions were mild; the risks of hypoglycaemia and weight gain did not increase. Anti-PEX168 antibodies were noted in less than 2% of patients. No treatment-emergent serious adverse events occurred.

CONCLUSION

The subcutaneous injection of PEX168 once a week can effectively, continuously and safely improve HbA1c levels in patients with T2D when combined with metformin.

The Real-World Observational Prospective Study of Health Outcomes with Dulaglutide and Liraglutide in Type 2 Diabetes Patients (TROPHIES): Baseline Patient-Reported Outcomes

INTRODUCTION

Although patient-reported outcome (PRO) measures provide important information beyond clinical data, studies that assess the PROs of type 2 diabetes mellitus (T2DM) patients initiating injectable glucose-lowering medications in routine clinical practice are limited. We describe the perspectives of patients based on a diversified panel of generic and disease-specific PRO measures at the time of enrollment (baseline) in the TROPHIES study.

METHODS

TROPHIES is a 24-month prospective observational study performed in France, Germany, and Italy in patients with T2DM who initiated their first injectable glucose-lowering medication with once-weekly dulaglutide or once-daily liraglutide. To better understand the perspectives of these patients regarding their overall health, treatment satisfaction, and quality of life and work, the patients' responses to the following questionnaires were collected at baseline before they initiated treatment with dulaglutide or liraglutide: EQ-5D-5L (scale: 0-1), EQ-VAS (visual analog scale: 0-100), Impact of Weight on Self-Perceptions Questionnaire (IW-SP; scale: 0-100), Diabetes Treatment Satisfaction Questionnaire Status (DTSQs; scale: 0-36), and Diabetes Productivity Measure (DPM; scale: 0-100). Analyses were descriptive in nature, with higher scores reflecting better outcomes.

RESULTS

Data from patients at the time of enrollment were analyzed. At baseline, patients initiating dulaglutide (N = 1130) or liraglutide (N = 1051) rated their quality of life in terms of mean EQ-5D-5L index as 0.84 and 0.83, and in terms of mean EQ-VAS as 67.5 and 67.5, respectively. The mean baseline scores in patients initiating dulaglutide or liraglutide were 59.8 and 61.3 for IW-SP, 24.6 and 25.8 for DTSQs, 78.6 and 79.5 for DPM Life Productivity, and 87.5 and 86.8 for DPM Work Productivity, respectively.

CONCLUSION

The information from this varied panel of PRO instruments collected at baseline complements clinical outcomes data.

Liraglutide accelerates colonic transit in people with type 1 diabetes and polyneuropathy: A randomised, double-blind, placebo-controlled trial

BACKGROUND

Glucagon-like peptide-1 receptor agonists, such as liraglutide, reduce hyperglycaemia and induce weight loss and are used as a treatment in diabetes. However, common adverse effects include nausea, loss of appetite and prolonged gastric emptying. It is not known whether these changes are centrally generated or if liraglutide alters the enteric motility.

OBJECTIVE

To investigate the effects of liraglutide on gastrointestinal function and symptoms.

METHODS

A total of 48 adults with type 1 diabetes and confirmed distal symmetric polyneuropathy were randomised to receive liraglutide 1.8 mg/day or placebo for 26 weeks. Regional transit times and motility indexes were assessed with a wireless motility capsule, whereas symptoms were evaluated using the validated gastroparesis cardinal symptom index.

RESULTS

Liraglutide treatment reduced large bowel transit time (31.7%, p = 0.04) and decreased motility index (6.1%, p = 0.04) compared to placebo, whereas the groups did not differ in gastric emptying or small-bowel transit times. Liraglutide increased postprandial fullness with 29% (p = 0.01). Increased small bowel transit time was associated with decreased bloating (p = 0.008).

CONCLUSION

Liraglutide accelerates large bowel transit and decreases motility index, which may indicate better coordination of propulsive motility. This potentially improves the function of the enteric nervous system, leading to normalised colonic function and positive effects in type 1 diabetes.

The Dual GLP-1/GIP Receptor Agonist DA4-JC Shows Superior Protective Properties Compared to the GLP-1 Analogue Liraglutide in the APP/PS1 Mouse Model of Alzheimer's Disease

Alzheimer's disease (AD) is a neurodegenerative disorder for which there is no cure. Here, we test a dual GLP-1/GIP receptor agonist (DA4-JC) that has a cell penetrating sequence added to enhance blood-brain barrier penetration. We show in a receptor activity study that DA4-JC has balanced activity on both GLP-1 and GIP receptors but not on GLP-2 or Glucagon receptors. A dose-response study in the APP/PS1 mouse model of AD showed both a dose-dependent drug effect on the inflammation response and the reduction of amyloid plaques in the brain. When comparing DA4-JC with the GLP-1 analogue liraglutide at equal doses of 10nmol/kg bw ip. once-daily for 8 weeks, DA4-JC was more effective in reversing memory loss, enhancing synaptic plasticity (LTP) in the hippocampus, reducing amyloid plaques and lowering pro-inflammatory cytokine levels in the brain. The results suggest that DA4-JC may be a novel treatment for AD.

Glucagon-like peptide-1 suppresses neuroinflammation and improves neural structure

Glucagon-like peptide-1 (GLP-1) is a hormone mainly secreted from enteroendocrine L cells. GLP-1 and its receptor are also expressed in the brain. GLP-1 signaling has pivotal roles in regulating neuroinflammation and memory function, but it is unclear how GLP-1 improves memory function by regulating neuroinflammation. Here, we demonstrated that GLP-1 enhances neural structure by inhibiting lipopolysaccharide (LPS)-induced inflammation in microglia with the effects of GLP-1 itself on neurons. Inflammatory secretions of BV-2 microglia by LPS aggravated mitochondrial function and cell survival, as well as neural structure in Neuro-2a neurons. In inflammatory condition, GLP-1 suppressed the secretion of tumor necrosis factor-alpha (TNF-α)-associated cytokines and chemokines in BV-2 microglia and ultimately enhanced neurite complexity (neurite length, number of neurites from soma, and secondary branches) in Neuro-2a neurons. We confirmed that GLP-1 improves neurite complexity, dendritic spine morphogenesis, and spine development in TNF-α-treated primary cortical neurons based on altered expression levels of the factors related to neurite growth and spine morphology. Given that our data that GLP-1 itself enhances neurite complexity and spine morphology in neurons, we suggest that GLP-1 has a therapeutic potential in central nervous system diseases.

Stable Evans Blue Derived Exendin-4 Peptide for Type 2 Diabetes Treatment

In the treatment of type 2 diabetes mellitus, it is very important to develop therapeutics with prolonged circulation half-life. Exendin-4 is a glucagon like peptide-1 receptor (GLP-1R) agonist that has been modified in different ways for imaging insulinoma and for treating type-2 diabetes. In this work, we synthesized a maleimide derivative of truncated Evans blue dye (MEB-C3-Mal) to conjugate with (Cys(40))exendin-4 to obtain a highly stable MEB-C3-(Cys(40))exendin-4 (denoted as Abextide II). Through in situ binding with endogenous albumin, Abextide II lowers blood glucose level and prolongs the hypoglycemic effect in a type 2 diabetes mouse model more than the FDA approved Albiglutide.

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.

Effects of E2HSA, a Long-Acting Glucagon Like Peptide-1 Receptor Agonist, on Glycemic Control and Beta Cell Function in Spontaneous Diabetic db/db Mice

Glucagon like peptide-1 (GLP-1) receptor agonists such as exendin-4 have been widely used but their short half-life limits their therapeutic value. The recombinant protein, E2HSA, is a novel, long-acting GLP-1 receptor agonist generated by the fusion of exendin-4 with human serum albumin. In mouse pancreatic NIT-1 cells, E2HSA activated GLP-1 receptor with similar efficacy as exendin-4. After single-dose administration in ICR mice, E2HSA showed prolonged glucose lowering effects which lasted up to four days and extended inhibition on gastric emptying for at least 72 hours. Chronic E2HSA treatment in db/db mice significantly improved glucose tolerance, reduced elevated nonfasting and fasting plasma glucose levels, and also decreased HbA1c levels. E2HSA also increased insulin secretion and decreased body weight and appetite. Furthermore, immunofluorescence analysis showed that E2HSA increased β-cell area, improved islet morphology, and reduced β-cell apoptosis. In accordance with the promotion of β-cell function and survival, E2HSA upregulated genes such as Irs2, Pdx-1, Nkx6.1, and MafA and downregulated the expression levels of FoxO1 and proapoptotic Bcl-2 family proteins. In conclusion, with prolonged glucose lowering effects and promoting β-cell function and survival, the fusion protein, E2HSA, is a promising new therapeutic for once weekly treatment of type 2 diabetes.

Effects of glucagon-like peptide-1 receptor agonists on non-alcoholic fatty liver disease and inflammation

Glucagon-like peptide1 (GLP-1) is secreted from Langerhans cells in response to oral nutrient intake. Glucagon-like peptide-1 receptor agonists (GLP-1RAs) are a new class of incretin-based anti-diabetic drugs. They function to stimulate insulin secretion while suppressing glucagon secretion. GLP-1-based therapies are now well established in the management of type 2 diabetes mellitus (T2DM), and recent literature has suggested potential applications of these drugs in the treatment of obesity and for protection against cardiovascular and neurological diseases. As we know, along with change in lifestyles, the prevalence of non-alcoholic fatty liver disease (NAFLD) in China is rising more than that of viral hepatitis and alcoholic fatty liver disease, and NAFLD has become the most common chronic liver disease in recent years. Recent studies further suggest that GLP-1RAs can reduce transaminase levels to improve NAFLD by improving blood lipid levels, cutting down the fat content to promote fat redistribution, directly decreasing fatty degeneration of the liver, reducing the degree of liver fibrosis and improving inflammation. This review shows the NAFLD-associated effects of GLP-1RAs in animal models and in patients with T2DM or obesity who are participants in clinical trials.

GLP-1 improves neuropathology after murine cold lesion brain trauma

OBJECTIVES

In this study, we address a gap in knowledge regarding the therapeutic potential of acute treatment with a glucagon-like peptide-1 (GLP-1) receptor agonist after severe brain trauma. Moreover, it remains still unknown whether GLP-1 treatment activates the protective, anti-neurodegenerative cAMP response element binding protein (CREB) pathway in the brain in vivo, and whether activation leads to observable increases in protective, anti-neurodegenerative proteins. Finally, we report the first use of a highly sensitive in vivo imaging agent to assess reactive species generation after brain trauma.

METHODS

Severe trauma was induced with a stereotactic cryo-lesion in mice and thereafter treated with vehicle, liraglutide, or liraglutide + GLP-1 receptor antagonist. A therapeutic window was established and lesion size post-trauma was determined. Reactive oxygen species were visualized in vivo and quantified directly ex vivo. Hematological analysis was performed over time. Necrotic and apoptotic tone and neuroinflammation was assessed over time. CREB activation and CREB-regulated cytoprotective proteins were assessed over time.

RESULTS

Lira treatment reduced lesion size by ∼50% through the GLP-1 receptor. Reactive species generation was reduced by ∼40-60%. Necrotic and apoptotic tone maintained similar to sham in diseased animals with Lira treatment. Phosphorylation of CREB was markedly increased by Lira in a GLP-1 receptor-dependent manner. CREB-regulated cytoprotective and anti-neurodegenerative proteins increased with Lira-driven CREB activation.

INTERPRETATION

These results show that Lira has potent effects after experimental trauma in mice and thus should be considered a candidate for critical care intervention post-injury. Moreover, activation of CREB in the brain by Lira - described for the first time to be dependent on pathology - should be investigated further as a potential mechanism of action in neurodegenerative disorders.

Albiglutide: clinical overview of a long-acting GLP-1 receptor agonist in the treatment of Type 2 diabetes

Glucagon-like peptide-1 receptor agonists have become an important therapeutic option for patients with Type 2 diabetes because of their ability to lower blood glucose and help patients lose weight. There are currently three glucagon-like peptide-1 receptor agonists on the market. In the near future, albiglutide will undergo review by the US FDA for possible approval. Results from Phase I/II trials have demonstrated that albiglutide is a safe and efficacious medication for treating Type 2 diabetes. It lowers hemoglobin A1c and decreases bodyweight. It appears to have fewer gastrointestinal side effects than liraglutide. The once-weekly (or possibly longer duration) dosing of albiglutide may improve adherence. Several Phase III trials are expected to be completed in 2013. These trials will shed further light on the safety and efficacy of albiglutide.

An Open-Label, Parallel Group Study Investigating the Effects of Age and Gender on the Pharmacokinetics of the Once-Daily Glucagon-Like Peptide-1 Analogue Liraglutide

Liraglutide is a once-daily glucagon-like peptide-1 analogue being developed for the treatment of type 2 diabetes. The aim of this study was to investigate the effect of age and gender on the pharmacokinetics of liraglutide. Eight male and 8 female subjects were recruited from an 18- to 45-year-old group and an over-65-year-old group, respectively. All subjects received a single subcutaneous dose of 1.0 mg liraglutide. The area under the liraglutide plasma concentration curve from time 0 to last quantifiable concentration adjusted for body weight (significant covariate; P = .001) was found to be equivalent in young and elderly subjects (primary end point), with an estimated ratio of 0.94 (90% confidence interval, 0.84-1.06; P = .39). No significant impact of gender was observed (P = .38; estimated ratio, 1.08; 90% confidence interval, 0.93-1.26). Adverse events were of mild or moderate severity. The most frequently reported events were headache, vomiting, and nausea. When adjusted for body weight, no effect of gender or age was found on the pharmacokinetics of liraglutide.

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.

Acute and chronic administration of SHR117887, a novel and specific dipeptidyl peptidase-4 inhibitor, improves metabolic control in diabetic rodent models

AIM

Dipeptidyl deptidase-4 (DPP-4) inhibitors are a new class of anti-diabetic agents. The purpose of this study was to assess the acute and chronic effects of SHR117887, a novel DPP-4 inhibitor, on metabolic control and pancreatic β-cell function in normal or diabetic rodent models.

METHODS

In the acute experiments, ICR mice, diet-induced obese (DIO) rats and ob/ob mice were subjected to an oral glucose tolerance test (OGTT) following a single oral administration of SHR117887 (0.1, 0.3, 1 or 3 mg/kg). Blood samples were collected to measure glucose, insulin, DPP-4 activity and active GLP-1 level. In the chronic experiments, ob/ob mice was administered SHR117887 (3, 10 or 30 mg/kg) twice daily for 33 d to assess the effects on metabolic control and pancreatic β-cell function. Vildagliptin (LAF237) was used as a positive control in all the experiments.

RESULTS

Acute oral administration of SHR117887 dose-dependently decreased the serum DPP-4 activity and improved glucose tolerance in ICR mice, DIO rats and ob/ob mice. This was accompanied by significant increases in the serum active GLP-1 and insulin levels. Chronic administration of SHR117887 significantly decreased fasting blood glucose level and improved the lipid profiles in ob/ob mice by reducing the serum triglyceride and free fatty acid levels, and its efficacy was comparable with that of vildagliptin at the same molarity. Moreover, chronic administration of SHR117887 increased the insulin staining of islet cells, which is suggestive of improved β-cell function.

CONCLUSION

SHR117887 is a potent DPP-4 inhibitor that improves metabolic control and β-cell function in diabetic rodent models, suggesting that it could be a new therapeutic agent for the treatment of type 2 diabetes.

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.

GLP-1 receptor agonists: a clinical perspective on cardiovascular effects

The active incretin hormone glucagon-like peptide-1(7-36)amide (GLP-1) is a 30-amino acid peptide that exerts glucoregulatory and insulinotropic actions by functioning as an agonist for the GLP-1 receptor (GLP-1R). In addition to its anti-diabetic effects, GLP-1 has demonstrated cardioprotective actions. Here we review the cardiovascular effects of the GLP-1 analogues currently approved for the treatment of type 2 diabetes, namely exenatide and liraglutide. We discuss their anti-hyperglycaemic efficacy, and offer a clinical perspective of their effects on cardiovascular risk factors such as body weight, blood pressure, heart rate and lipid profiles, as well as their potential consequences on cardiovascular events, such as arrhythmias, heart failure, myocardial infarction and death. Lastly, we briefly review additional GLP-1R agonists in clinical development.

Liraglutide: clinical pharmacology and considerations for therapy

Liraglutide is a United States Food and Drug Administration (FDA)-approved glucagon-like peptide-1 (GLP-1) analog that is 97% homologous to native human GLP-1. The additional 16-carbon fatty acid chain causes noncovalent binding to albumin, which slows absorption from the injection site and protects the molecule from degradation by the enzyme dipeptidyl peptidase-4, allowing for protraction of action. Albumin binding and an elimination half-life of 13 hours combine to allow for once-daily dosing. Liraglutide 1.2 and 1.8 mg/day given as monotherapy for up to 52 weeks produced mean reductions in hemoglobin A1c (A1C) of 0.6-1.6%; combination therapy of liraglutide with oral antidiabetic agents demonstrated mean A1C reductions up to 1.5%. The satiety effect of GLP-1 receptor agonists and documented weight loss as great as 3.38 kg in clinical trials may make liraglutide ideal for obese patients with type 2 diabetes mellitus. Like other incretin-based agents, preliminary studies suggest liraglutide may also increase β-cell mass and function. Hypoglycemia is rare with liraglutide and tends to occur when used in combination with sulfonylureas; liraglutide in combination with insulin is not yet FDA approved. The pharmacokinetic parameters of liraglutide are unaffected by age, sex, race, or ethnicity, and no special recommendations for altered dosing of liraglutide need apply to populations with hepatic or renal impairment. Results from clinical trials have not shown an increased risk of medullary thyroid cancer, pancreatitis, or poor cardiovascular outcomes with liraglutide treatment. Ongoing, long-term monitoring studies continue to evaluate the safety of liraglutide treatment in these outcomes.

Administration of an acylated GLP-1 and GIP preparation provides added beneficial glucose-lowering and insulinotropic actions over single incretins in mice with Type 2 diabetes and obesity

The present study examined the glucose-lowering and insulinotropic properties of acylated GLP-1 (glucagon-like peptide-1) and GIP (glucose-dependent insulinotropic polypeptide) peptides in Type 2 diabetes and obesity. GLP-1, GIP, Liraglutide, N-AcGIP(Lys(37)Myr) (N-acetylGIP with myristic acid conjugated at Lys(37)), a simple combination of both peptides and a Lira-AcGIP preparation [overnight preparation of Liraglutide and N-AcGIP(Lys(37)Myr)] were incubated with DPP-IV (dipeptidyl peptidase-IV) to assess peptide stability, and BRIN-BD11 cells were used to evaluate cAMP production and insulin secretion. Acute glucose-lowering and insulinotropic actions were evaluated in Swiss TO mice. Subchronic studies on glucose homoeostasis, insulin secretion, food intake and bodyweight were evaluated in ob/ob mice. Liraglutide, N-AcGIP(Lys(37)Myr), a simple combination of both peptides and the Lira-AcGIP preparation demonstrated improved DPP-IV resistance (P<0.001), while stimulating cAMP production and insulin secretion (1.4-2-fold; P<0.001). The Lira-AcGIP preparation was more potent at lowering plasma glucose (20-51% reduction; P<0.05-P<0.001) and stimulating insulin secretion (1.5-1.8-fold; P<0.05-P<0.001) compared with Liraglutide and N-AcGIP(Lys(37)Myr) or a simple peptide combination. Daily administration of the Lira-AcGIP preparation to ob/ob mice lowered bodyweight (7-9%; P<0.05), food intake (23%; P<0.05) and plasma glucose (46% reduction; P<0.001), while increasing plasma insulin (1.5-1.6-fold; P<0.001). The Lira-AcGIP preparation enhanced glucose tolerance, insulin response to glucose and insulin content (P<0.05-P<0.001). These findings demonstrate that a combined preparation of the acylated GLP-1 and GIP peptides Liraglutide and N-AcGIP(Lys(37)Myr) markedly improved glucose-lowering and insulinotropic properties in diabetic obesity compared with either incretin mimetic given individually.

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.

Glucagon-like peptide-1 analog liraglutide in combination with sulfonylurea safely improves blood glucose measures vs sulfonylurea monotherapy in Japanese patients with type 2 diabetes: Results of a 52-week, randomized, multicenter trial

Aims/Introduction:  Sulfonylurea (SU) agents are the most effective drugs at lowering blood glucose when used alone. However, their effectiveness declines after a certain period. The addition of liraglutide to existing SU therapy might reverse some of the known drawbacks of SU.

MATERIALS AND METHODS

  This multicenter, randomized, 52-week study assessed the long-term efficacy and safety of adding liraglutide at 0.6 or 0.9 mg/day to existing SU therapy in Japanese patients with inadequately controlled type 2 diabetes.

RESULTS

  In total, 264 patients were enrolled and received treatment. At week 52, HbA1c in the liraglutide 0.6 mg, liraglutide 0.9 mg and placebo groups was reduced from 9.00 to 7.91%, from 8.61 to 7.33%, and from 8.85 to 8.79%, respectively. The mean difference of HbA1c (95% CI) in the liraglutide 0.6 and 0.9 mg groups vs the placebo group was 0.96 (-1.25 to -0.67) and -1.33 (-1.62 to -1.04), respectively. For the liraglutide 0.6 mg, 0.9 mg and placebo groups, the Japanese Diabetes Society target HbA1c of <6.9% was achieved by 15.1, 39.1 and 4.5% of patients, respectively. Mean fasting plasma glucose at week 52 was lower in the liraglutide groups compared with the placebo group, and mean bodyweight remained unchanged in the liraglutide groups. Most subjects in all three treatment groups reported mild adverse events. No major hypoglycemic episode was reported.

CONCLUSIONS

  Once-daily administration of liraglutide in combination with SU for 52 weeks provided favorable metabolic control, a safety profile and did not alter bodyweight. This trial was registered with ClinicalTrial.gov (no. NCT00395746). (J Diabetes Invest,doi: 10.1111/j.2040-1124.2011.00103.x, 2011).

Review of the therapeutic uses of liraglutide

BACKGROUND

Glucagon-like peptide (GLP-1) is a neuroendocrine hormone that increases blood glucose and is a drug target for treatment of type 2 diabetes. Liraglutide, a subcutaneous, once-daily GLP-1 agonist, is approved for the treatment of type 2 diabetes in the United States and Europe. It also has been studied for weight loss.

OBJECTIVE

The purpose of this article is to review all of the relevant literature on the chemistry, pharmacology, pharmacokinetics, metabolism, clinical trials, safety, drug interactions, cost, and place in therapy of liraglutide.

METHODS

Literature searches of MEDLINE between 1969 and September 2010, International Pharmaceutical Abstracts between 1970 and September 2010, American Diabetes Association Meeting abstracts (2008-2010), and European Association for the Study of Diabetes abstracts (2008-2010) were performed using liraglutide, Victoza, and NN2211 as key terms.

RESULTS

Thirteen randomized controlled trials were identified and summarized. Liraglutide has been shown to increase glucose-dependent insulin release by 34% to 118% and reduce postprandial glucagon levels by 20%. Studies showed that liraglutide, as monotherapy and in combination with glimepiride, metformin, and/or rosiglitazone, lowers glycosylated hemoglobin (HbA(1c)) between 0.84% and 1.5%. Transient nausea was reported by 7% to 40% of subjects. Severe hypoglycemia-glucose <55 mg/dL-was observed by 2.5% of subjects in 1 trial.

CONCLUSION

Liraglutide safely and effectively reduces HbA(1c) in patients with type 2 diabetes. The most recent American Diabetes Association guidelines recommended a GLP-1 agonist along with metformin as a second-tier therapy for type 2 diabetes. Although the American Association of Clinical Endocrinologists/American College of Endocrinologists' guidelines recommended it for first-line monotherapy in patients with HbA(1c) between 6.5% and 7.5% and with metformin if HbA(1c) is between 7.6% and 8.5%, liraglutide should be considered for patients who cannot tolerate first-line agents or if an additional agent is needed to help reach target HbA(1c) goals.

Early clinical studies with liraglutide

AIMS

To describe Phase 1 and 2 clinical trials of liraglutide with a focus on clinical pharmacology.

KEY FINDINGS

In early clinical trials of liraglutide, 0.05-1.9 mg daily improved multiple aspects of glycaemic control and beta-cell function. Early trials demonstrated typical reductions in glycated haemoglobin (HbA(1c) ) and fasting plasma glucose (FPG) of up to 1.5% and 3.3-3.9 mmol/l, respectively, at daily doses of 1.25-1.9 mg, with 45-50% of patients reaching HbA(1c) < 7%. The effects of liraglutide in restoring beta-cell response to fasting and postprandial hyperglycaemia and in reinstating near-normal insulin secretion under hyperglycaemic conditions suggest a beta-cell-protective effect. By delaying gastric emptying and promoting satiety, liraglutide is weight sparing at low doses and causes clinically meaningful weight loss at higher doses and in combination with other anti-diabetes therapies with weight-modifying benefits, such as metformin. Significant improvements in other cardiovascular risk factors, including blood pressure, lipids and cardiovascular risk biomarkers, were also evident. Adverse effects of liraglutide were primarily gastrointestinal; dose-dependent nausea was the most commonly reported effect, but was typically mild-to-moderate in severity and transient in nature.

CONCLUSIONS

Early clinical trials of liraglutide indicate the ability to improve glycaemic control in a glucose-dependent manner, with low risk of hypoglycaemia. Promotion of weight loss, along with improvements in multiple cardiovascular risk factors, suggests that liraglutide may offer a novel and clinically valuable approach to disease management for patients with type 2 diabetes.

Glucagon-like peptide-1 receptor agonists and cardiovascular events: a meta-analysis of randomized clinical trials

Objective. Data from randomized clinical trials with metabolic outcomes can be used to address concerns about potential issues of cardiovascular safety for newer drugs for type 2 diabetes. This meta-analysis was designed to assess cardiovascular safety of GLP-1 receptor agonists. Design and Methods. MEDLINE, Embase, and Cochrane databases were searched for randomized trials of GLP-1 receptor agonists (versus placebo or other comparators) with a duration ≥12 weeks, performed in type 2 diabetic patients. Mantel-Haenszel odds ratio with 95% confidence interval (MH-OR) was calculated for major cardiovascular events (MACE), on an intention-to-treat basis, excluding trials with zero events. Results. Out of 36 trials, 20 reported at least one MACE. The MH-OR for all GLP-1 receptor agonists was 0.74 (0.50–1.08), P = .12 (0.85 (0.50–1.45), P = .55, and 0.69 (0.40–1.22), P = .20, for exenatide and liraglutide, resp.). Corresponding figures for placebo-controlled and active comparator studies were 0.46 (0.25–0.83), P = .009, and 1.05 (0.63–1.76), P = .84, respectively. Conclusions. To date, results of randomized trials do not suggest any detrimental effect of GLP-1 receptor agonists on cardiovascular events. Specifically designed longer-term trials are needed to verify the possibility of a beneficial effect.

Influence of hepatic impairment on pharmacokinetics of the human GLP-1 analogue, liraglutide

AIMS

To compare the pharmacokinetics (PK) of a single-dose of liraglutide in subjects with hepatic impairment.

METHODS

This parallel group, open label trial involved four groups of six subjects with healthy, mild, moderate and severe hepatic impairment, respectively. Each subject received 0.75 mg of liraglutide (s.c., thigh), and blood samples were taken over 72 h for PK assessment. Standard laboratory and safety data were collected. The primary endpoint was area under the plasma liraglutide concentration–time curve from time zero to infinity (AUC(0,∞)).

RESULTS

Exposure to liraglutide was not increased by hepatic impairment. On the contrary, mean AUC(0,∞) was highest for healthy subjects and lowest for subjects with severe hepatic impairment (severe/healthy: 0.56, with 90% CI 0.39, 0.81) and equivalence in this parameter across groups was not demonstrated. C_max also tended to decrease with hepatic impairment (severe/healthy: 0.71, with 90% CI 0.52, 0.97), but t_max was similar across groups (11.3–13.2 h). There were no serious adverse events, hypoglycaemic episodes or clinically significant changes in laboratory parameters and liraglutide was considered well tolerated.

CONCLUSIONS

This study indicated no safety concerns regarding use of liraglutide in patients with hepatic impairment. Exposure to liraglutide was not increased by impaired liver function; rather, the results suggest a decreased exposure with increasing degree of hepatic impairment. However, data are not conclusive to suggest a dose increase of liraglutide. Thus, the results indicate that patients with type 2 diabetes mellitus and hepatic impairment can use standard treatment regimens of liraglutide. There is, however, currently limited clinical experience with liraglutide in patients with hepatic impairment.

GLP-1 playing the role of a gut regulatory compound

Gastric emptying is the first step in the metabolic endocrine cascade that takes place after food intake. The incretin hormones originating in the gut, particularly GLP-1, exert multiple antihyperglycaemic actions such as enhancement of glucose-dependent insulin secretion, suppression of glucagon secretion, slowing of gastric emptying with an ensuing decrease in food intake and weight loss. From extensive studies in experimental animals and humans we have found that GLP-1 also exerts a motility-inhibiting and antispasmodic effect in the gut that was verified in healthy volunteers and patients with irritable bowel syndrome (IBS). In order to further investigate the effect of GLP-1 in humans, we used the dipeptidyl peptidase-IV resistant GLP-1 analogue ROSE-010, thereby extending its biological activity. A randomized, double-blinded, prospective clinical trial was carried out in order to investigate the effect of two doses of ROSE-010 in 166 patients suffering from pain attacks of IBS. We found that injections of ROSE-010 were twice as effective as placebo in terms of total pain relief response in those affected by pain attacks due to IBS. Our results show that basal physiological research studies can be translated into clinical use. The current pharmaceutical incentive with incretin mimetics, such as GLP-1 analogues and exenatide, is an interesting development that apart from its obvious use in diabetes type 2, may also be useful in terms of gut motility-regulating effects with effects on appetite, food intake and motility disorders that may provide an opportunity to bring about new improvements in medical care.

Liraglutide in the management of type 2 diabetes

The pathophysiology of type 2 diabetes has been attributed to the classic triad of decreased insulin secretion, increased insulin resistance, and elevated hepatic glucose production. Research has shown additional mechanisms, including incretin deficiency or resistance in the gastrointestinal tract. Liraglutide is a modified form of human glucagon-like peptide-1. Liraglutide was obtained by substitution of lysine 34 for arginine near the NH2 terminus, and by addition of a C16 fatty acid at the ɛ-amino group of lysine (at position 26) using a γ-glutamic acid spacer. Liraglutide has demonstrated glucose-dependent insulin secretion, improvements in β-cell function, deceleration of gastric emptying, and promotion of early satiety leading to weight loss. Liraglutide has the potential to acquire an important role, not only in the treatment of type 2 diabetes, but also in preservation of β-cell function, weight loss, and prevention of chronic diabetic complications.

Selecting GLP-1 agonists in the management of type 2 diabetes: differential pharmacology and therapeutic benefits of liraglutide and exenatide

Failure of secretion of the incretin hormone glucagon-like peptide-1 (GLP-1) plays a prominent role in type 2 diabetes, and restoration of GLP-1 action is an important therapeutic objective. Although the short duration of action of GLP-1 renders it unsuited to therapeutic use, 2 long-acting GLP-1 receptor agonists, exenatide and liraglutide, represent a significant advance in treatment. In controlled trials, both produce short-term glucose-lowering effects, with the reduction in hemoglobin A(1c) of up to 1.3%. These responses are often superior to those observed with additional oral agents. However, unlike sulfonylureas, thiazolidinediones, or insulin, all of which lead to significant weight gain, GLP-1 receptor agonists uniquely result in long-term weight loss of around 5 kg, and higher doses may enhance this further. Reduction in blood pressure of 2-7 mm Hg also has been observed. Both drugs produce transient mild gastrointestinal side effects; although mild hypoglycemia can occur, this is usually in combination with other hypoglycemic therapies. However, serious hypoglycemia and acute pancreatitis are rare. The once-daily dosage of liraglutide makes it more convenient than twice-daily dosage of prandial exenatide, and a superior glucose-lowering effect was observed in the only head-to-head comparison reported so far. Besides cost, these considerations currently favor liraglutide over exenatide. Further studies are needed to confirm long-term safety, and most importantly, that short-term benefits translate into long-term reductions of diabetes-related cardiovascular events and other complications.

Dose-dependent effects of the once-daily GLP-1 receptor agonist lixisenatide in patients with Type 2 diabetes inadequately controlled with metformin: a randomized, double-blind, placebo-controlled trial

AIMS

To evaluate the dose-response relationship of lixisenatide (AVE0010), a glucagon-like peptide-1 (GLP-1) receptor agonist, in metformin-treated patients with Type 2 diabetes.

METHODS

Randomized, double-blind, placebo-controlled, parallel-group, 13 week study of 542 patients with Type 2 diabetes inadequately controlled [glycated haemoglobin (HbA(1c)) > or = 7.0 and < 9.0% (> or = 53 and < 75 mmol/mol)] on metformin (> or = 1000 mg/day) treated with subcutaneous lixisenatide doses of 5, 10, 20 or 30 microg once daily or twice daily or placebo. The primary end-point was change in HbA(1c) from baseline to 13 weeks in the intent-to-treat population.

RESULTS

Lixisenatide significantly improved mean HbA(1c) from a baseline of 7.55% (59.0 mmol/mol); respective mean reductions for 5, 10, 20 and 30 microg doses were 0.47, 0.50, 0.69 and 0.76% (5.1, 5.5, 7.5 and 8.3 mmol/mol), on once-daily and 0.65, 0.78, 0.75 and 0.87% (7.1, 8.5, 8.2 and 9.5 mmol/mol) on twice-daily administrations vs. 0.18% (2.0 mmol/mol) with placebo (all P < 0.01 vs. placebo). Target HbA(1c) < 7.0% (53 mmol/mol) at study end was achieved in 68% of patients receiving 20 and 30 microg once-daily lixisenatide vs. 32% receiving placebo (P < 0.0001). Dose-dependent improvements were observed for fasting, postprandial and average self-monitored seven-point blood glucose levels. Weight changes ranged from -2.0 to -3.9 kg with lixisenatide vs. -1.9 kg with placebo. The most frequent adverse event was mild-to-moderate nausea.

CONCLUSIONS

Lixisenatide significantly improved glycaemic control in mildly hyperglycaemic patients with Type 2 diabetes on metformin. Dose-response relationships were seen for once- and twice-daily regimens, with similar efficacy levels, with a 20 microg once-daily dose of lixisenatide demonstrating the best efficacy-to-tolerability ratio. This new, once-daily GLP-1 receptor agonist shows promise in the management of Type 2 diabetes to be defined further by ongoing long-term studies.

Clinical studies of liraglutide, a novel, once-daily human glucagon-like peptide-1 analog for improved management of type 2 diabetes mellitus

Liraglutide, a new glucagon-like peptide-1 (GLP-1)-receptor agonist with 97% homology to human GLP-1, can be administered once/day independent of meals in patients with type 2 diabetes mellitus. Clinical trials have demonstrated its efficacy in controlling hyperglycemia, helping patients achieve hemoglobin A(1c) level goals; in facilitating weight loss, and in improving indexes of beta-cell function when used alone or in combination with metformin, glimepiride, or rosiglitazone. These studies also suggest that liraglutide may be associated with modest improvements in systolic blood pressure. Data from a comparative trial of liraglutide and insulin glargine have suggested that liraglutide provides greater glycemic control with less weight gain, and another study demonstrated that liraglutide provides greater improvements in glycemic control with less hypoglycemia than exenatide and with comparable weight loss. Although liraglutide is well tolerated and is associated with low rates of hypoglycemia, transient and mild nausea can occur when therapy is initiated. However, rates of hypoglycemia appear to be lower and nausea appears to be less persistent with liraglutide than with exenatide. Even though data on the long-term use of liraglutide are still needed, this drug may provide a useful treatment option in patients poorly controlled with dietary modification and exercise and in those whose diabetes is inadequately controlled by oral antidiabetic agents.

Emerging role of GLP-1 receptor agonists in the treatment of obesity

The prevalence of obesity has increased dramatically in recent decades, both in the US and worldwide. Pharmacotherapy can augment the weight-reducing effects of lifestyle modification and can facilitate long-term weight maintenance. However, there is a paucity of pharmacologic agents approved for the treatment of obesity, and the use of existing weight loss medications is frequently limited by contraindications, drug interactions, adverse effects, limited coverage by third-party payers, and cost. In recent years, there has been an increased understanding and appreciation of the role of gastrointestinal hormones in the control of body weight. One such hormone, GLP-1, also plays an important role in glucose homeostasis. GLP-1 receptor agonists, such as exenatide and liraglutide, have been developed and are already approved for the treatment of type 2 diabetes. There has also been interest in the use of GLP-1 receptor agonists for the treatment of obesity in nondiabetic patients. This review explores the potential utility and limitations of exenatide and liraglutide as therapeutic agents for obesity.

Liraglutide, the once-daily human GLP-1 analog, in the treatment of Type 2 diabetes

Type 2 diabetes is a progressive disorder characterized by continuous deterioration in β-cell function requiring an escalation of therapeutic efforts in order to maintain glycemic control. Recent studies have demonstrated that the current antidiabetic treatments, including metformin, sulfonylureas and thiazolidinediones, are not durable, resulting in an increase of hemoglobin A_1c over time with all three therapies. Many current antidiabetic treatments (sulfonylureas, thiazolidinediones and insulin) are associated with the undesirable feature of weight gain. In addition, sulfonylureas and insulin are associated with an increased risk for hypoglycemia. The unsatisfactory results with the current pharmacological therapies for Type 2 diabetes have encouraged the development of a number of novel treatments. Among these are the incretin-based therapies, which include glucagon-like peptide (GLP)-1 receptor agonists; this article focuses on one of these agonists, the human GLP-1 analog liraglutide. Liraglutide has been approved for use in Type 2 diabetic individuals in several countries, including Europe, the USA and Japan.

Liraglutide

Each month, subscribers to The Formulary Monograph Service receive five to six well-documented monographs on drugs that are newly released or are in late phase 3 trials. The monographs are targeted to the Pharmacy & Therapeutics Committee. Subscribers also receive monthly 1-page summary monographs on each agent that are useful for agendas and pharmacy/nursing inservices. A comprehensive target drug utilization evaluation (DUE) is also provided each month. With a subscription, the monographs are sent in print and are also available online. Monographs can be customized to meet the needs of a facility. Subscribers to The Formulary Monograph Service also receive access to a pharmacy bulletin board, The Formulary Information Exchange (The F.I.X.). All topics pertinent to clinical and hospital pharmacy are discussed on The F.I.X. Through the cooperation of The Formulary, Hospital Pharmacy publishes selected reviews in this column. For more information about The Formulary Monograph Service or The F.I.X., call The Formulary at 800-322-4349 or e-mail Dennis.Cada@wolterskluwer.com . The July 2010 monograph topics are everolimus in renal transplantation, miconazole buccal, sipuleucel-T, apixaban, and polidocanol. The DUE/MUE is on everolimus.

Diabesity: therapeutic options

A pathogenic relationship exists between type 2 diabetes and obesity. Over the last decade, the escalation in diabetes cases has paralleled the rapid increase in obesity rates, constituting a global health crisis. Environmental risk factors attributed to the global increase in obesity include the consumption of high-calorie, high-fat foods and inadequate physical activity. Obese individuals may also have a genetic predisposition for obesity. Both diabetes and obesity confer an elevated risk of developing a range of complications and comorbidities, including cardiovascular disease, hypertension and stroke, which can complicate disease management. This review examines the aetiology of the linkages between diabetes and obesity and the range of available therapies. Recent clinical evidence substantiating the efficacy and safety of incretin-based antidiabetic therapies is analysed, in addition to data on antiobesity therapeutic strategies, such as antiobesity agents, behaviour modification and bariatric surgery. Glucose control is often accompanied by weight-neutral or modest weight reduction effects with DPP-4 inhibitor treatment (sitagliptin, vildagliptin, saxagliptin) and weight loss with GLP-1 receptor agonist therapy (exenatide, liraglutide). Studies of antiobesity agents including orlistat, sibutramine and rimonabant have shown attrition rates of 30-40%, and the long-term effects of these agents remain unknown. Bariatric surgical procedures commonly performed are laparoscopic adjustable banding of the stomach and the Roux-en-Y gastric bypass, and have produced type 2 diabetes remission rates of up to 73%. Therapeutic strategies that integrate glycaemic control and weight loss will assume greater importance as the prevalence of diabetes and obesity increase.

Association of pancreatitis with glucagon-like peptide-1 agonist use

OBJECTIVE

To review the possible association between glucagon-like peptide-1 (GLP-1) agonist use and pancreatitis in patients with type 2 diabetes mellitus.

DATA SOURCES

A MEDLINE search (1950-January 2010) identified key clinical trials delineating adverse effects associated with GLP-1 agonist use. Key search terms included type 2 diabetes mellitus, pancreatitis, incretins, exenatide, liraglutide, albiglutide, and taspoglutide. Review of references listed in the articles identified was also performed. The Food and Drug Administration (FDA) Web site and Amylin Pharmaceuticals file data were utilized to extract case report information and unpublished clinical development data related to GLP-1 agonist use and pancreatitis.

STUDY SELECTION AND DATA EXTRACTION

Phase 2 and 3 clinical trials evaluating exenatide, liraglutide, albiglutide, and taspoglutide that discussed treatmentrelated adverse effects as well as FDA-reviewed case reports of pancreatitis in patients taking these same therapies were included. One study evaluating type 2 diabetes as a risk factor for development of acute pancreatitis was also included. Exenatide case reports and clinical development data were also included.

DATA SYNTHESIS

Currently there have been 8 cases during clinical development and 36 postmarketing reports of acute pancreatitis in exenatide-treated patients. Four patients have developed acute (n = 3) or chronic (1) pancreatitis during liraglutide clinical trials. There have been no reports to date of development of acute pancreatitis in patients taking albiglutide or taspoglutide.

CONCLUSIONS

Observational reports and clinical trial data suggest an association between GLP-1 agonist use and acute pancreatitis; however, additional clinical trial data and in-depth case report analysis are needed to further evaluate and verify this finding.

Liraglutide in the treatment of type 2 diabetes mellitus: clinical utility and patient perspectives

Type 2 diabetes mellitus (T2DM) is a progressive disease associated with significant morbidity and mortality. There is good evidence that intensive glycemic control reduces the development and progression of complications in patients with diabetes. In order to achieve glycemic targets, patients often require a combination of oral therapy and/or insulin in addition to lifestyle modification. Unfortunately many currently available therapies for T2DM are associated with weight gain and hypoglycemia resulting in poor compliance and subsequent worsening glycemic control. Glucagon like peptide-1 (GLP-1) is an incretin hormone secreted from the small intestine that lowers fasting and postprandial glucose through multiple mechanisms including glucose-dependent insulin secretion, reduction of glucagon secretion, delaying gastric emptying and increased satiety. Liraglutide is a long acting GLP-1 mimetic that is administered once a day by subcutaneous injection and is now licensed for the treatment of T2DM. Phase 3 clinical trials have demonstrated beneficial effects on glycemic control and weight with liraglutide therapy. Within this article, we provide an overview of pharmacology, efficacy, safety and patient experience on liraglutide in the management of T2DM.

Glucagon-like peptide-1 gastrointestinal regulatory role in metabolism and motility

Gastrointestinal (GI) motility, primarily gastric emptying, balances the hormonal output that takes place after food intake in order to maintain stable blood sugar. The incretin hormones, glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic peptide (GIP), work together to reduce postprandial hyperglycemia by glucose-dependent insulin secretion and inhibition of glucagon release, as well as inhibition of GI motility and gastric emptying. GLP-1 is considered the more effective of the two incretins due to its additional inhibitory effects on GI motility. It is observed that patients on treatment with GLP-1 analogues or exenatide achieve a considerable weight loss during treatment. This is of benefit to improve insulin resistance in type 2 diabetes. Furthermore, weight loss per se is of considerable benefit in an even longer health perspective. The weight loss is considered to be due to the inhibition of GI motility. This effect has been studied in animal experimentation, and from there taken to involve studies on GI motility in healthy volunteers and patients with irritable bowel syndrome (IBS). Evolving to a phase II study in IBS, the GLP-1 analogue (ROSE-010) was recently shown to be effective for treatment of acute pain attacks in IBS. Taken together, data speak in favor of GI motility as a central component not only in metabolic disorders but also in IBS, be it due to a direct relaxing effect on GI smooth muscle or a slow emptying of gastric contents resulting in a less outspoken nutritional demand on hormonal regulatory functions in the GI tract.

Glycaemic control in type 2 diabetes: targets and new therapies

Type 2 diabetes mellitus (T2DM) is a worldwide public health challenge. Despite the availability of many antidiabetes agents and pharmacotherapies targeting cardiovascular risk factors, the morbidity, mortality and economic consequences of T2DM are still a great burden to patients, society, health care systems and the economy. The need for new therapies for glycaemic control is compounded by the fact that existing treatments have limitations either because of their side effects (particularly weight gain and hypoglycaemia) or contraindications that limit their use. Furthermore, none of the current therapies have a significant impact on disease progression. Incretin-based therapies offer a new therapeutic approach to the management of T2DM, and there are also several even newer therapies in development. There are two groups of incretin-based therapies currently available; dipeptidyl peptidase-4 (DPP-4) inhibitors and GLP-1 analogues/mimetics. The former are given orally while the latter subcutaneously. These drugs result in glucose-dependent insulin secretion and glucose-dependent glucagon suppression, with consequent low risk of hypoglycaemia when used as mono- or combination therapy (except when used with sulphonylureas). In addition, they are either weight neutral in the case of DPP-4 inhibitors or cause weight loss in the case of incretin mimetics/analogues. Furthermore, animal studies have shown that these agents prolong beta cell survival which offers the theoretical possibility of slowing the progression to T2DM. In this article we will review the currently available antidiabetes agents with particular emphasis on incretin-based and future therapies. In addition, we will review and discuss the evidence relating to glycaemic control and cardiovascular disease.

Chemical modification of class II G protein-coupled receptor ligands: frontiers in the development of peptide analogs as neuroendocrine pharmacological therapies

Recent research and clinical data have begun to demonstrate the huge potential therapeutic importance of ligands that modulate the activity of the secretin-like, Class II, G protein-coupled receptors (GPCRs). Ligands that can modulate the activity of these Class II GPCRs may have important clinical roles in the treatment of a wide variety of conditions such as osteoporosis, diabetes, amyotrophic lateral sclerosis and autism spectrum disorders. While these receptors present important new therapeutic targets, the large glycoprotein nature of their cognate ligands poses many problems with respect to therapeutic peptidergic drug design. These native peptides often exhibit poor bioavailability, metabolic instability, poor receptor selectivity and resultant low potencies in vivo. Recently, increased attention has been paid to the structural modification of these peptides to enhance their therapeutic efficacy. Successful modification strategies have included d-amino acid substitutions, selective truncation, and fatty acid acylation of the peptide. Through these and other processes, these novel peptide ligand analogs can demonstrate enhanced receptor subtype selectivity, directed signal transduction pathway activation, resistance to proteolytic degradation, and improved systemic bioavailability. In the future, it is likely, through additional modification strategies such as addition of circulation-stabilizing transferrin moieties, that the therapeutic pharmacopeia of drugs targeted towards Class II secretin-like receptors may rival that of the Class I rhodopsin-like receptors that currently provide the majority of clinically used GPCR-based therapeutics. Currently, Class II-based drugs include synthesized analogs of vasoactive intestinal peptide for type 2 diabetes or parathyroid hormone for osteoporosis.

Exenatide and liraglutide: different approaches to develop GLP-1 receptor agonists (incretin mimetics)--preclinical and clinical results

The GLP-1 analogues exenatide and liraglutide stimulate insulin secretion and inhibit glucagon output in a glucose-dependent manner, slow gastric emptying and decrease appetite. The injectable glucagon-like peptide-1 (GLP-1) receptor agonist exenatide significantly improves glycaemic control, with average reductions in HbA1c of about 1.0% point, fasting plasma glucose of about 1.4 mmol l(-1), and causes a weight loss of approximately 2-3 kg after 30 weeks of treatment. The adverse effects are transient nausea and vomiting. The long-acting once-daily human GLP-1 receptor agonist liraglutide reduces HbA1c by about 1.0-2.0% point, weight by 1-3 kg and seems to have fewer gastrointestinal side effects than exenatide. The final place of the GLP-1 receptor agonists in the diabetes treatment algorithm will be clarified when we have long-term trials with cardiovascular end-points and data illustrating the effects on the progression of type 2 diabetes.