Glucagon-like peptide-1 therapy and the exocrine pancreas: innocent bystander or friendly fire?

The impact of GLP-1 signalling on the energy metabolism of pancreatic islet β-cells and extrapancreatic tissues

Glucagon-like peptide-1 signalling impacts glucose homeostasis and appetite thereby indirectly affecting substrate availability at the whole-body level. The incretin canonically produces an insulinotropic effect, thereby lowering blood glucose levels by promoting the uptake and inhibiting the production of the sugar by peripheral tissues. Likewise, GLP-1 signalling within the central nervous system reduces the appetite and food intake, whereas its gastric effect delays the absorption of nutrients, thus improving glycaemic control and reducing the risk of postprandial hyperglycaemia. We review the molecular aspects of the GLP-1 signalling, focusing on its impact on intracellular energy metabolism. Whilst the incretin exerts its effects predominantly via a Gs receptor, which decodes the incretin signal into the elevation of intracellular cAMP levels, the downstream signalling cascades within the cell, acting on fast and slow timescales, resulting in an enhancement or an attenuation of glucose catabolism, respectively.

Depression and Associated Risk Factors Among Type 2 Diabetic Patients: A Cross Sectional Study on a Convenience Sample from the Diabetic Center, Khamis Mushait; Saudi Arabia

BACKGROUND

Studies had confirmed that diabetic patients have a greater risk for developing depression. Our objectives were to estimate the prevalence and predictors of depression among type 2 diabetic patients.

METHODS

A cross-sectional study at the Diabetic Center, Armed Forces Hospital-Southern Region (AFHSR), Khamis Mushait was conducted in the period from March to June 2017. The study includes a convenience sample of type 2 diabetic patients. Self-administered questionnaires were utilized. It consists of personal characteristics, diabetes-related information's, and the Arabic version of the Patient Health Questionnaire (PHQ-9). Proper statistical analyses were done to assess the significance of the correlates with p ≤ 0.05 considered significant.

RESULTS

The study included 350 diabetic patients out of 410 with a response rate of 85.4%. Their age ranged between 28 and 100 years with a mean ±SD of 61.4±13 years. The prevalence of depression among them was 36.6%. Logistic regression revealed that patients older than 50 years were at lower risk for developing depression as compared to those aged between 28 and 40 years OR and 95% CI were 0.21 (0.08-0.57), 0.30 (0.12-0.78) and 0.33 (0.12-0.91) for patients in the age groups 51-60, 61-70 and > 70 years, respectively. Diabetic patients with thyroid dysfunction, neuropathy, those treated with insulin, and noncompliant patients were at double risk for developing depression compared to their counterparts (OR = 2.26, 95% CI = 1.20-4.27, p = 0.012); (OR = 2.35, 95% CI = 1.22-4.53, p = 0.011); (OR = 1.92, 95% CI = 1.08-3.40, p = 0.026); (AOR = 2.14, 95% CI = 1.01-4.53, p = 0.047) respectively.

CONCLUSION

Almost one third of type 2 diabetic patients were depressed. Younger patients, having comorbid thyroid disorders or neuropathy, those treated with insulin and noncompliant patients were at higher risk for developing depression. Proper screening and treatment of depression is a crucial part of the health care management of diabetic people.

Inventing Liraglutide, a Glucagon-Like Peptide-1 Analogue, for the Treatment of Diabetes and Obesity

Glucagon-like peptide-1 (GLP-1) has been in focus since the early 1980s as a long looked for incretin hormone, released from the gastrointestinal tract and with an important effect on glucose-dependent insulin secretion, providing efficient glucose lowering, with little risk for hypoglycemia. The enzyme dipeptidyl peptidase-4 (DPP-4) degrades GLP-1 very fast, and the remaining metabolite is cleared rapidly by the kidneys. Liraglutide is a fatty acid acylated analogue of GLP-1 that provides efficacy for 24 h/day. The mechanism of action for liraglutide is reviewed in detail with focus on pancreatic efficacy and safety, thyroid safety, and weight loss mechanism. Evolving science hypothesizes that GLP-1 has important effects on atherosclerosis, relevant for the cardiovascular benefit seen in the treatment of diabetes and obesity. Also, GLP-1 may be relevant in neurodegenerative diseases.

Fighting Type-2 Diabetes: Present and Future Perspectives

BACKGROUND

Type-2 diabetes mellitus accounts for 80-90% of diabetic patients. So far, the treatment of diabetes mainly aims at elevating insulin level and lowering glucose level in the peripheral blood and mitigating insulin resistance. Physiologically, insulin secretion from pancreatic β cells is delicately regulated. Thus, how insulin-related therapies could titrate blood glucose appropriately and avoid the occurrence of hypoglycemia remains an important issue for decades. Similar question is addressed on how to attenuate vascular complication in diabetic subjects.

METHODS

We overviewed the evolution of each class of anti-diabetic drugs that have been used in clinical practice, focusing on their mechanisms, clinical results and cautions.

RESULTS

Glucagon-like peptide-1 receptor agonists stimulate β cells for insulin secretion in response to diet but not in fasting stage, which make them superior than conventional insulinsecretion stimulators. DPP-4 inhibitors suppress glucagon-like peptide-1 degradation. Sodium/ glucose co-transporter 2 inhibitors enhance glucose clearance through urine excretion. The appearance of these new drugs provides new information about glycemic control. We update the clinical findings of Glucagon-like peptide-1 receptor agonists, DPP-4 inhibitors and Sodium/glucose cotransporter 2 inhibitors in glycemic control and the risk or progression of cardiovascular disease in diabetic patients. Stem cell therapy might be an alternative tool for diabetic patients to improve β cell regeneration and peripheral ischemia. We summarize the clinical results of mesenchymal stem cells transplanted into patients with diabetic limb and foot.

CONCLUSION

A stepwise intensification of dual and triple therapy for individual diabetic patient is required to achieve therapeutic target.

Histological changes in endocrine and exocrine pancreatic tissue from patients exposed to incretin-based therapies

AIMS

Incretin-based therapies have been associated with an increased risk of pancreatitis. Recently, various histological abnormalities have been reported in human pancreatic tissue from brain-dead organ donors who had been exposed to incretin-based drugs. In the present study we examined pancreatic tissue collected at surgery.

METHODS

Human pancreatic tissue from 7 type 2-diabetic patients treated with incretin-based drugs (type 2-I), 6 diabetic patients without incretin treatment (type 2-NI), 11 patients without diabetes (no diabetes group) and 9 brain-dead organ donors (BDOD group) was examined.

RESULTS

Fractional beta-cell area was reduced in the type 2-NI group compared to the group without diabetes (P < .05), but there was no difference compared to the type 2-I patients. Alpha-cell area (P = .30), beta-cell replication (P = .17) and alpha-cell replication (P = .91) were not different. There were also no differences in acinar cell (P = .13) and duct cell replication (P = .099). Insulin-positive duct cells were more frequent in the type 2-I and the BDOD groups (P = .034). No co-expression of insulin and glucagon was detected. Pancreatic intraepithelial neoplasia (PanIN) lesions were very rare, all low-grade (PanIN 1a and 1b) and tended to occur more frequently in the type 2-I group (P = .084).

CONCLUSIONS

The present results did not reveal marked histological abnormalities in the pancreas of incretin-treated patients with type 2 diabetes. Low numbers of specimens available and a large inter-individual variability of the findings warrant caution regarding the interpretation of histological data concerning drug effects on the human pancreas.

The New Era of Drug Therapy for Obesity: The Evidence and the Expectations

There is an urgent need for effective pharmacological therapies to help tackle the growing obesity epidemic and the healthcare crisis it poses. The past 3 years have seen approval of a number of novel anti-obesity drugs. The majority of these influence hypothalamic appetite pathways via dopaminergic or serotoninergic signalling. Some are combination therapies, allowing lower doses to minimize the potential for off-target effects. An alternative approach is to mimic endogenous satiety signals using long-lasting forms of peripheral appetite-suppressing hormones. There is also considerable interest in targeting thermogenesis by brown adipose tissue to increase resting energy expenditure. Obesity pharmacotherapy has seen several false dawns, but improved understanding of the pathways regulating energy balance, and better-designed trials, give many greater confidence that recently approved agents will be both efficacious and safe. Nevertheless, a number of issues from preclinical and clinical development continue to attract debate, and additional large-scale trials are still required to address areas of uncertainty.

Cardiovascular, renal and gastrointestinal effects of incretin-based therapies: an acute and 12-week randomised, double-blind, placebo-controlled, mechanistic intervention trial in type 2 diabetes

INTRODUCTION

Incretin-based therapies, that is, glucagon-like peptide (GLP)-1 receptor agonists and dipeptidyl peptidase (DPP)-4 inhibitors, are relatively novel antihyperglycaemic drugs that are frequently used in type 2 diabetes management. Apart from glucose-lowering, these agents exhibit pleiotropic actions that may have favourable and unfavourable clinical consequences. Incretin-based therapies have been associated with heart rate acceleration, heart failure, acute renal failure and acute pancreatitis. Conversely, these agents may reduce blood pressure, glomerular hyperfiltration, albuminuria and hepatic steatosis. While large-sized cardiovascular safety trials can potentially identify the clinical significance of some of these pleiotropic actions, small-sized mechanistic studies are important to understand the (patho)physiological rationale of these findings. The current protocol describes a mechanistic study to assess cardiovascular, renal and gastrointestinal effects, and mechanisms of incretin-based therapies in type 2 diabetes.

METHODS AND ANALYSES

60 patients with type 2 diabetes will undergo acute and prolonged randomised, double-blind, intervention studies. The acute intervention will consist of intravenous administration of the GLP-1 receptor agonist exenatide or placebo. For the prolonged intervention, patients will be randomised to 12-week treatment with the GLP-1 receptor agonist liraglutide, the DPP-4 inhibitor sitagliptin or matching placebos. For each examined organ system, a primary end point is defined. Primary cardiovascular end point is change in resting heart rate variability assessed by beat-to-beat heart rate monitor and spectral analyses software. Primary renal end point is change in glomerular filtration rate assessed by the classic inulin clearance methodology. Primary gastrointestinal end points are change in pancreatic exocrine function assessed by MRI-techniques (acute intervention) and faecal elastase-1 levels (12-week intervention). Secondary end points include systemic haemodynamics, microvascular function, effective renal plasma flow, renal tubular function, pancreatic volume and gallbladder emptying-rate.

MEDICAL ETHICS AND DISSEMINATION

The study is approved by the local Ethics Review Board (VU University Medical Center, Amsterdam) and conducted in accordance with the Declaration of Helsinki and Good Clinical Practice.

TRIAL REGISTRATION NUMBER

NCT01744236.

The glucagon-like peptide-1-based therapeutics exenatide and saxagliptin did not cause detrimental effects on the pancreas in mice, rats, dogs and monkeys

AIMS

Recent reports in the literature have suggested that glucagon-like peptide-1 (GLP-1)-based therapies may lead to increased risk of pancreatic pathology leading to chronic pancreatic injury and pancreatic neoplasia. Extensive non-clinical and clinical safety testing was conducted to support the global development of exenatide twice daily, exenatide once weekly and saxagliptin. Our aim was to integrate these non-clinical data obtained with both mechanisms of GLP-1-based drugs to provide complementary data regarding the potential for drug-induced pancreatic safety signals.

METHODS

More than 70 regulated non-clinical toxicology studies in rodents and non-rodents were conducted in accordance with International Conference on Harmonisation and US Food and Drug Administration guidance documents, current industry standards, animal welfare regulations and in compliance with Good Laboratory Practice regulations. Treatment duration was up to 2 years in rodents and up to 12 months in non-rodents using high doses representing large multiples of human exposures (up to 130× for exenatide and 2200× for saxagliptin). Comprehensive pancreas assessments involved more than 2400 pancreata from animals exposed to exenatide and over 1700 pancreata from animals exposed to saxagliptin.

RESULTS

Neither exenatide nor saxagliptin treatment resulted in drug-related microscopic changes indicative of acute or chronic adverse effects (including neoplasia) in the endocrine or exocrine pancreas, at doses far exceeding the maximum human systemic exposures.

CONCLUSIONS

These data substantially add to the weight of evidence supporting the lack of non-clinical drug-induced pancreatic safety signals in animals exposed to GLP-1-based therapies.

Divergent effects of liraglutide, exendin-4, and sitagliptin on beta-cell mass and indicators of pancreatitis in a mouse model of hyperglycaemia

AIMS

Glucagon-like peptide-1 (GLP-1) receptor agonists and dipeptidyl peptidase-4 (DPP4) inhibitors improve glucose tolerance by still incompletely understood mechanisms. Each class of antihyperglycemic drugs has also been proposed to increase pancreatitis risk. Here, we compare systematically the effects of two widely-used GLP-1 analogues, liraglutide and exendin-4, and the DPP4 inhibitor, sitagliptin, in the mouse.

METHODS

C57BL6 mice were maintained for 131 days on a normal diet (ND) or a diet comprising 60% fat (HFD) before measurements of fasting blood glucose and insulin, and intraperitoneal glucose tolerance. Beta- and alpha- cell volume, and Reg3b immunoreactivity, were measured by immunohistochemical analysis of pancreatic slices.

RESULTS

Whereas liraglutide (200 µg/kg) and exendin-4 (10 µg/kg) treatment reduced body weight and/or improved glucose tolerance, sitagliptin (10 mg/kg) was without effect on either parameter. Liraglutide caused a sharp reduction in beta-cell mass in both ND and HFD mice, whereas exendin-4 exerted no effect. By contrast, sitagliptin unmasked an action of high fat diet to increase beta-cell mass. Reg3B positive area was augmented by all three agents in normal chow-fed mice, whilst sitagliptin and exendin-4, but not liraglutide, affected this parameter in HFD animals. Correspondingly sitagliptin, but not the GLP-1 analogues, increased circulating amylase levels in ND and HFD mice.

CONCLUSIONS

Liraglutide improves glucose tolerance in the mouse whilst exerting relatively modest effects on pancreatitis risk. Conversely, exendin-4 and sitagliptin, at doses which exert, respectively, minor or no effects on metabolic parameters, lead to signs of pancreatitis.

Studying pancreatic risks caused by incretin-based therapies: is it a game? It's not a game!

A manuscript published recently on histological changes induced in the pancreas by incretin-based medications has been widely criticized because of ill-matched groups treated with incretin-based versus non-incretin-based medications and because of methodological problems identifying glucagon-producing cells. Now a study making use of the same tissue bank is available, and does not easily confirm the bulk of findings originally reported. This is an important opportunity to discuss the responsibility of authors to publish results potentially reproducible by other scientists as an important quality criterion, and the responsibility of reviewers and editors in handling such manuscripts. The main conclusion is that attempts to reproduce controversial findings are a necessity if finally the essence of novel results is at stake.

Incretins and the intensivist: what are they and what does an intensivist need to know about them?

Hyperglycaemia occurs frequently in the critically ill, even in those patients without a history of diabetes. The mechanisms underlying hyperglycaemia in this group are complex and incompletely defined. In health, the gastrointestinal tract is an important modulator of postprandial glycaemic excursions and both the rate of gastric emptying and the so-called incretin hormones, glucagon-like peptide-1 and glucose-dependent insulinotropic polypeptide, are pivotal determinants of postprandial glycaemia. Incretin-based therapies (that is, glucagon-like peptide- 1 agonists and dipeptidyl-peptidase-4 inhibitors) have recently been incorporated into standard algorithms for the management of hyperglycaemia in ambulant patients with type 2 diabetes and, inevitably, an increasing number of patients who were receiving these classes of drugs prior to their acute illness will present to ICUs. This paper summarises current knowledge of the incretin effect as well as the incretin-based therapies that are available for the management of type 2 diabetes, and provides suggestions for the potential relevance of these agents in the management of dysglycaemia in the critically ill, particularly to normalise elevated blood glucose levels.

Distal gastrectomy in pancreaticoduodenectomy is associated with accelerated gastric emptying, enhanced postprandial release of GLP-1, and improved insulin sensitivity

OBJECTIVE

This study aims to investigate the relationship between gastric emptying, postprandial GLP-1 and insulin sensitivity after pancreaticoduodenectomy (PD).

BACKGROUND

Abnormal glucose regulation is highly prevalent in patients with pancreatic neoplasm and resolves in some after PD, the cause of which is unclear. The procedure is carried out with pylorus preservation (PPPD) or with distal gastrectomy (Whipple procedure). Accelerated gastric emptying and ensuing enhanced release of glucagon-like peptide-1 (GLP-1) conceivably play a role in glucose metabolism after PD. It was the purpose of this study to shed light on the relationship between gastric emptying, GLP-1 and glycemic control after PPPD and the Whipple procedure.

METHODS

A 75-g oral glucose tolerance test was carried out in 13 patients having undergone PPPD and in 13 after the Whipple procedure, median age 61 (range, 32-70) years, following an interval of 23 (range, 5-199) months. Gastric emptying was measured by the paracetamol absorption method. Plasma concentrations of glucose, insulin, GLP-1 and paracetamol were measured at baseline, 10, 20, 30 60, 90, 120, 150 and 180 min. Homeostasis model assessment-estimated insulin resistance (HOMA-IR) and oral glucose insulin sensitivity were calculated from glucose and insulin concentrations.

RESULTS

Patients with Whipple procedure as compared to PPPD had accelerated gastric emptying (p = 0.01) which correlated with early (0-30 min) integrated GLP-1 (AUC30; r (2) = 0.61; p = 0.02) and insulin sensitivity (r (2) = 0.41; p = 0.026) and inversely with HOMA-IR (r (2) = 0.17; p = 0.033). Two of 13 Whipple patients (15 %) as compared to seven of 13 after PPPD (54 %) had postload glucose concentrations (i.e. 120 min postmeal) ≥200 mg/dl (p < 0.05). None of 13 (0 %) after Whipple procedure but four of 13 patients (31 %) after PPPD had fasting glucose concentrations ≥126 mg/dl (p < 0.05) CONCLUSIONS: Gastric emptying was accelerated after Whipple procedure as compared to patients who have undergone PPPD, resulting in higher postprandial GLP-1 concentrations and insulin sensitivity and improved glycemic control.

PSCs and GLP-1R: occurrence in normal pancreas, acute/chronic pancreatitis and effect of their activation by a GLP-1R agonist

There is increasing concern about the development of pancreatitis in patients with diabetes mellitus who received long-term glucagon-like peptide-1 (GLP-1) analog treatment. Its pathogenesis is unknown. The effects of GLP-1 agonists on pancreatic endocrine cells are well studied; however, there is little information on effects on other pancreatic tissues that might be involved in inflammatory processes. Pancreatic stellate cells (PSCs) can have an important role in pancreatitis, secreting various inflammatory cytokines/chemokines, as well as collagen. In this study, we investigated GLP-1R occurrence in normal pancreas, acute pancreatitis (AP)/chronic pancreatitis (CP), and the effects of GLP-1 analog on normal PSCs, their ability to stimulate inflammatory mediator secretion or proliferation. GLP-1 receptor (GLP-1R) expression/localization in normal pancreas and pancreatitis (AP/CP) tissues were evaluated with histological/immunohistochemical analysis. PSCs were isolated from male Wistar rats. GLP-1R expression and effects of GLP-1 analog on activated PSCs was examined with real-time PCR, MTS assays and western blotting. In normal pancreas, pancreatic β cells expressed GLP-1R, with only low expression in acinar cells, whereas in AP or CP, acinar cells, ductal cells and activated PSCs expressed GLP-1R. With activation of normal PSCs, GLP-1R is markedly increased, as is multiple other incretin-related receptors. The GLP-1 analog, liraglutide, did not induce inflammatory genes expression in activated PSCs, but induced proliferation. Liraglutide activated multiple signaling cascades in PSCs, and the extracellular signal-regulated kinase pathway mediated the PSCs proliferation. GLP-1Rs are expressed in normal pancreas and there is marked enhanced expression in AP/CP. GLP-1-agonist induced cell proliferation of activated PSCs without increasing release of inflammatory mediators. These results suggest chronic treatment with GLP-1R agonists could lead to proliferation/chronic activation of PSCs, which may lead to important effects in the pancreas.

Diabetes, antihyperglycemic medications and cancer risk: smoke or fire?

OBJECTIVE

The aim of this review article is to discuss the epidemiological links between diabetes and cancer; the potential biological mechanisms linking diabetes, obesity and cancer; the risk of cancer associated with antidiabetic medications.

METHODS

The data discussed in this review were obtained from the American Association of Clinical Endocrinologists Consensus Conference on Diabetes and Cancer, held in New York, NY, USA, September 2012.

RESULTS

The results of these studies demonstrate a significant association between diabetes and the risk of multiple cancers, including hepatocellular, pancreatic, endometrial, colorectal, breast, kidney, bladder, gastric, and ovarian cancer, non-Hodgkin lymphoma, T cell lymphoma and leukemia. There are multiple potential biological mechanisms that may link type 2 diabetes, obesity and cancer. Insulin resistance and hyperinsulinemia may lead to direct activation of the insulin receptors on tumor cells and promote tumor growth. Other potential mechanisms include increased circulating, local or bioavailable insulin-like growth factor 1, hyperglycemia, dyslipidemia, increased circulating or local estrogen, adipokines and direct and indirect effects of inflammatory cytokines. Epidemiological studies have had conflicting results regarding the associations between various classes of antidiabetic medication and cancer development. Animal studies have demonstrated increased tumor growth with certain medications, but their relevance to humans is uncertain. Metformin may, however, have protective effects on cancer development and may improve survival in patients with cancer.

CONCLUSION

We describe the current understanding of the links among diabetes, antidiabetic medication and cancer risk. We highlight some of the issues that should be addressed in the future to prevent cancer development and death in those with diabetes.

Diabetes treatments and cancer risk: the importance of considering aspects of drug exposure

Investigations of the association between diabetes, diabetes treatments, and cancer risk have raised several epidemiological challenges. In particular, a patient's exposure to glucose-lowering drugs needs to be represented accurately to allow unbiased assessment of the link between the treatments and cancer risk. Many studies have used a simple binary contrast (exposure to a specific drug vs no exposure), which has potentially serious drawbacks. In addition, methods used to determine the duration and cumulative dose of drug exposure differ widely between studies. In this Review, we discuss representation of drug exposure in pharmacoepidemiological investigations of the connection between diabetes drugs and cancer risk. We identify principles that might improve future research (particularly in observational studies), and consider issues related to reverse causation and detection bias.

Advances in pharmacologic therapies for type 2 diabetes

Type 2 diabetes (T2DM) is a multi-causal, heterogeneous and progressive cardiometabolic condition, with an increasing prevalence worldwide. T2DM is associated with multiple comorbidities that may impact patients' quality of life. Treatment is multifactorial, but pharmacologic treatment of hyperglycemia is still regarded as the mainstay of diabetes management. Current established therapies include metformin, sulfonylurea agents and insulin, the long-term use of which was associated with reduced micro- and macrovascular events in the United Kingdom Prospective Diabetes Study. Despite major recent advances in diabetes care, a large proportion of patients remain in poor glycemic control, necessitating the development of new therapeutic options. The recently published position statement of the American Diabetes Association and European Association for the Study of Diabetes for the management of hyperglycemia in T2DM has accommodated this wider range of therapy choices, as it is less prescriptive and advocates an individualized treatment approach, taking into account many relevant patient- and disease-related factors. This review summarizes the updates on various established agents as well as the recent developments with regard to incretin-based therapies, inhibitors of the renal tubular sodium-glucose-linked-transporter-2 and ultra-long acting basal insulin formulations.

A critical analysis of the clinical use of incretin-based therapies: The benefits by far outweigh the potential risks

There is no question that incretin-based glucose-lowering medications have proven to be effective glucose-lowering agents. Glucagon-like peptide 1 (GLP-1) receptor agonists demonstrate an efficacy comparable to insulin treatment and appear to do so with significant effects to promote weight loss with minimal hypoglycemia. In addition, there are significant data with dipeptidyl peptidase 4 (DPP-4) inhibitors showing efficacy comparable to sulfonylureas but with weight neutral effects and reduced risk for hypoglycemia. However, over the recent past there have been concerns regarding the long-term consequences of using such therapies, and the issues raised are in regard to the potential of both classes to promote acute pancreatitis, to initiate histological changes suggesting chronic pancreatitis including associated preneoplastic lesions, and potentially, in the long run, pancreatic cancer. Other issues relate to an increase in thyroid cancer. There are clearly conflicting data that have been presented in preclinical studies and in epidemiologic studies. To provide an understanding of both sides of the argument, we provide a discussion of this topic as part of this two-part point-counterpoint narrative. In the point narrative preceding the counterpoint narrative below, Dr. Butler and colleagues provide their opinion and review of the data to date and that we need to reconsider use of incretin-based therapies because of the growing concern of potential risk and based on a clearer understanding of the mechanism of action. In the counterpoint narrative provided below, Dr. Nauck provides a defense of incretin-based therapies and that benefits clearly outweigh any concern of risk.

No evidence of drug-induced pancreatitis in rats treated with exenatide for 13 weeks

AIMS

The potential association of glucagon-like peptide receptor agonists (GLP-1RAs) with the development of pancreatitis or pancreatic malignancies in patients with diabetes has been suggested. This study evaluated the long-term effects of the GLP-1RA exenatide on pancreatic exocrine structure and function in the Zucker diabetic fatty (ZDF) rat model of type 2 diabetes.

METHODS

Rats received subcutaneous twice-daily injections of 0 (control), 6, 40 and 250 µg/kg/day exenatide for 3 months. Clinical signs, body and pancreas weight, food consumption, HbA1c, fasting serum amylase, lipase, glucose and insulin concentrations were evaluated during treatment and after a 28-day off-drug period to assess the reversibility of any observed effects. Morphometric analysis of pancreatic ductal cell proliferation and apoptosis were performed.

RESULTS

Plasma exenatide concentrations were several-fold higher than therapeutic levels observed in humans. No exenatide-related effects were observed on clinical signs, lipase concentration, pancreatic weight, pancreatic histology, ductal cell proliferation or apoptosis. Exenatide improved animal survival, physical condition, glucose concentrations and HbA1c, decreased food intake, and increased serum insulin concentration. Total amylase concentrations, although within normal ranges, were slightly higher in exenatide-treated rats; following the off-drug period, total amylase concentrations were comparable in treated and untreated rats. Exenatide-related minimal-to-moderate islet hypertrophy was observed at doses ≥6 µg/kg/day, with dose-related increases in incidence and degree. These changes were still present after the off-drug period.

CONCLUSIONS

Chronic administration of exenatide in ZDF rats resulted in the expected metabolic benefits and improved animal survival, with no adverse effects noted on pancreatic exocrine structure and function.

Gliptins (dipeptidyl peptidase-4 inhibitors) and risk of acute pancreatitis

INTRODUCTION

Dipeptidyl peptidase-4 (DPP-4) inhibitors (gliptins) play an increasing role in the management of type 2 diabetes. Such incretin-based therapies offer some advantages over other glucose-lowering agents, but might be associated with an increased risk of acute pancreatitis.

AREAS COVERED

An extensive literature search was performed to analyze clinical cases of acute pancreatitis reported in the literature or to the Food and Drug Administration (FDA), in randomized clinical trials, and in observational studies with five DPP-4 inhibitors: sitagliptin, vildagliptin, saxagliptin, alogliptin, and linagliptin.

EXPERT OPINION

An increased risk of pancreatitis has been reported in diabetic versus nondiabetic patients. Several anecdotal clinical cases of pancreatitis have been reported with sitagliptin and vildagliptin and an increased relative risk reported to the FDA with sitagliptin versus other comparators, but reporting bias cannot be excluded. In rather short-term clinical trials with well-selected diabetic patients, no increased risk of acute pancreatitis has been observed with any of the five commercialized DPP-4 inhibitors: sitagliptin, vildagliptin, saxagliptin, alogliptin, and linagliptin. Similarly, real-life cohort studies showed no increased incidence of pancreatitis with gliptins compared with other glucose-lowering agents, a finding recently challenged by a case- control study. These results must be confirmed in postmarketing surveillance programs and in ongoing large prospective trials with cardiovascular outcomes.

Relative risk of acute pancreatitis in initiators of exenatide twice daily compared with other anti-diabetic medication: a follow-up study

AIMS

Previously, a retrospective cohort study found no increased risk of acute pancreatitis with current or recent use of exenatide twice daily compared with use of other anti-diabetic drugs. This follow-up study investigated incident acute pancreatitis, with the use of a different data source and analytic method, in patients exposed to exenatide twice daily compared with patients exposed to other anti-diabetic medications.

METHODS

A large US health insurance claims database was used. Eligible patients had ≥ 9 months continuous enrollment without a claim for pancreatitis and a claim for a new anti-diabetic medication on or after 1 June 2005 to 31 March 2009. Cases of acute pancreatitis were defined as hospitalized patients with an Internation Classification of Disease 9 code of 577.0 in the primary position. A discrete time survival model was used to evaluate the relationship between exenatide twice daily and acute pancreatitis.

RESULTS

Of 482,034 eligible patients, 24,237 initiated exenatide twice daily and 457,797 initiated another anti-diabetic medication. Initiators of exenatide twice daily had more severe diabetes compared with initiators of other anti-diabetic medications. After adjustments for propensity score, insulin and use of medication potentially associated with acute pancreatitis, the odds ratio with exenatide twice daily exposure was 0.95 (95% CI 0.65-1.38). A secondary analysis that examined current, recent and past medication exposure found no increased risk of acute pancreatitis with exenatide twice daily, regardless of exposure category.

CONCLUSION

This study indicates that exposure to exenatide twice daily was not associated with an increased risk of acute pancreatitis compared with exposure to other anti-diabetic medications. These results should be interpreted in light of potential residual confounding and unknown biases.

Elevated amylase and lipase levels in patients using glucagonlike peptide-1 receptor agonists or dipeptidyl-peptidase-4 inhibitors in the outpatient setting

OBJECTIVE

To investigate the effects of glucagonlike peptidase-1 (GLP-1) receptor agonists and dipeptidyl-peptidase-4 (DPP-4) inhibitors on serum amylase and serum lipase levels in patients with type 2 diabetes.

METHODS

In 90 patients with type 2 diabetes, treatment was initiated with a GLP-1 agonist or a DPP-4 inhibitor. A comparison group consisted of 33 patients with type 2 diabetes and similar characteristics who were not prescribed these agents. Baseline serum amylase and lipase levels were measured in all patients and repeated periodically. We determined the percentage of patients with elevated levels of serum amylase or lipase (or both) in both groups.

RESULTS

Among all 90 patients who received a GLP-1 receptor agonist or a DPP-4 inhibitor, 32 (36%) had an increase in serum amylase or lipase (or both) in comparison with 6 of 33 patients (18%) with such increases in the comparison group. Interestingly, the serum lipase levels increased more than the serum amylase values in all groups. To ascertain that this was not a chance laboratory error, serum samples were submitted to a second independent laboratory, and the same results were obtained. Usually, use of the medication was discontinued when serum lipase or amylase values were found to be elevated at any level.

CONCLUSION

Both GLP-1 receptor agonists and DPP-4 inhibitors are associated with increased levels of serum lipase more than serum amylase in many patients with type 2 diabetes, possibly suggesting the presence of pancreatic inflammation. Whether this finding may potentially lead to acute pancreatitis or chronic pancreatitis, as reported in rat models, is currently unknown. Careful observation of patients taking these medications may be prudent.

Inflammation and incretins

Nutrient excess results in systemic inflammation in diabetes contributing to insulin resistance, dyslipidaemia and increased cardiovascular risk. GLP-1 agonists and DPP-4 inhibitors, which are now well accepted therapies for diabetes may play a unique role in modulating this inflammatory process. Incretin based therapies have shown beneficial anti-inflammatory effects on surrogate markers but cardiovascular outcome data is still lacking.

Relative risk of acute pancreatitis in initiators of exenatide twice daily compared with other anti-diabetic medication: a follow-up study

AIMS

Previously, a retrospective cohort study found no increased risk of acute pancreatitis with current or recent use of exenatide twice daily compared with use of other anti-diabetic drugs. This follow-up study investigated incident acute pancreatitis, with the use of a different data source and analytic method, in patients exposed to exenatide twice daily compared with patients exposed to other anti-diabetic medications.

METHODS

A large US health insurance claims database was used. Eligible patients had ≥ 9 months continuous enrollment without a claim for pancreatitis and a claim for a new anti-diabetic medication on or after 1 June 2005 to 31 March 2009. Cases of acute pancreatitis were defined as hospitalized patients with an Internation Classification of Disease 9 code of 577.0 in the primary position. A discrete time survival model was used to evaluate the relationship between exenatide twice daily and acute pancreatitis.

RESULTS

Of 482,034 eligible patients, 24,237 initiated exenatide twice daily and 457,797 initiated another anti-diabetic medication. Initiators of exenatide twice daily had more severe diabetes compared with initiators of other anti-diabetic medications. After adjustments for propensity score, insulin and use of medication potentially associated with acute pancreatitis, the odds ratio with exenatide twice daily exposure was 0.95 (95% CI 0.65-1.38). A secondary analysis that examined current, recent and past medication exposure found no increased risk of acute pancreatitis with exenatide twice daily, regardless of exposure category.

CONCLUSION

This study indicates that exposure to exenatide twice daily was not associated with an increased risk of acute pancreatitis compared with exposure to other anti-diabetic medications. These results should be interpreted in light of potential residual confounding and unknown biases.

The effects of 13 wk of liraglutide treatment on endocrine and exocrine pancreas in male and female ZDF rats: a quantitative and qualitative analysis revealing no evidence of drug-induced pancreatitis

A possible association between glucagon-like peptide-1 (GLP-1) analogs and incidences of pancreatitis has been suggested based on clinical studies. In male and female diabetic Zucker diabetic fatty (ZDF) rats, we investigated the effects of continuous administration of liraglutide and exenatide on biochemical [lipase, pancreatic amylase (P-amylase)] and histopathological markers of pancreatitis. Male and female ZDF rats were dosed for 13 wk with liraglutide (0.4 or 1.0 mg·kg(-1)·day(-1) sc once daily) or exenatide (0.25 mg·kg(-1)·day(-1) sc, Alzet osmotic minipumps). P-amylase and lipase plasma activity were measured, and an extended histopathological and stereological (specific cell mass and proliferation rate) evaluation of the exocrine and the endocrine pancreas was performed. Expectedly, liraglutide and exenatide lowered blood glucose and Hb A(1c) in male and female ZDF rats, whereas β-cell mass and proliferation rate were increased with greatly improved blood glucose control. Whereas neither analog affected lipase activity, small increases in P-amylase activity were observed in animals treated with liraglutide and exenatide. However, concurrent or permanent increases in lipase and P-amylase activity were never observed. Triglycerides were lowered by both GLP-1 analogs. The qualitative histopathological findings did not reveal adverse effects of liraglutide. The findings were mainly minimal in severity and focal in distribution. Similarly, the quantitative stereological analyses revealed no effects of liraglutide or exenatide on overall pancreas weight or exocrine and duct cell mass or proliferation. The present study demonstrates that, in overtly diabetic male and female ZDF rats, prolonged exposure to GLP-1 receptor agonists does not affect biochemical or histopathological markers of pancreatitis, and whereas both exenatide and liraglutide increase β-cell mass, they have no effect on the exocrine pancreas. However, clinical outcome studies and studies using primate tissues and/or studies in nonhuman primates are needed to further assess human risk.

The human GLP-1 analog liraglutide and the pancreas: evidence for the absence of structural pancreatic changes in three species

Glucagon-like peptide (GLP)-1 analogs have been implicated as a risk factor for pancreatitis in humans. We investigated whether liraglutide, the once-daily human GLP-1 analog, induces pancreatitis in rats, mice, and monkeys. Pancreata from mice, rats, and nonhuman primates were examined macro- and microscopically. Evaluation of preneoplastic proliferative lesions in the pancreata from nonhuman primates was performed. After 2 years of treatment, 3 of 79 male mice in the control group and 2, 1, 1, and 1 mice in the different liraglutide groups (of 67-79 mice per group) had pancreatitis based on microscopic criteria. For females, the numbers were 0 of 79 mice in the control group and 3 mice in all the liraglutide groups (of 66-76 mice per group). Pancreatitis was not the cause of death in any animals. There were no cases of pancreatitis, macroscopically or microscopically, in 400 rats. Neither pancreatitis nor preneoplastic proliferative lesions was found in monkeys dosed for 87 weeks, with plasma liraglutide exposure 60-fold higher than that observed in humans at the maximal clinical dose. In conclusion, liraglutide did not induce pancreatitis in mice, rats, or monkeys when dosed for up to 2 years and at exposure levels up to 60 times higher than in humans.

A review of gliptins in 2011

INTRODUCTION

Dipeptidylpeptidase-4 (DPP-4) inhibitors offer new options for the management of type 2 diabetes (T2DM).

AREAS COVERED

This paper is an updated review, providing an analysis of both the similarities and the differences between the various compounds known as gliptins, currently used in the clinic (sitagliptin, vildagliptin, saxagliptin, alogliptin and linagliptin). This paper discusses the pharmacokinetic and pharmacodynamic characteristics of gliptins; both the efficacy and safety profiles of gliptins in clinical trials (compared with classical glucose-lowering agents), given as monotherapy or in combination, including in special populations; the positioning of DPP-4 inhibitors in the management of T2DM in recent guidelines; and various unanswered questions and perspectives.

EXPERT OPINION

The role of DPP-4 inhibitors in the therapeutic armamentarium of T2DM is evolving, as their potential strengths and weaknesses become better defined. Future critical issues may include the durability of glucose control, resulting from better β-cell protection, positive effects on cardiovascular outcomes and long-term safety issues.

Saxagliptin plus metformin combination therapy

Metformin is considered to be the first-line drug therapy for the management of Type 2 diabetes. Incretin-based therapies, and especially dipeptidyl peptidase-4 inhibitors, offer new opportunities after failure of metformin. An extensive literature search was performed to analyze all clinical trials combining saxagliptin with metformin. Saxagliptin and metformin may be administered together, either separately or in fixed-dose combination, as saxagliptin added to metformin or as an initial combination. Saxagliptin and metformin are not prone to pharmacokinetic drug-drug interactions and fixed-dose combination allows dosing of one single pill (Kombiglyze^® XR) or two pills (Komboglyze^®) per day. Both compounds exert pharmacodynamic complementary actions. Their coadministration improves blood glucose control (fasting plasma glucose, postprandial glucose and glycated hemoglobin) more potently than either compound separately. Tolerance is good without hypoglycemia, weight gain and further increase in metformin-related gastrointestinal adverse events. The combination saxagliptin plus metformin may be used as first-line or second-line therapy in the management of Type 2 diabetes.

Vildagliptin-induced acute pancreatitis

OBJECTIVE

To describe the first reported case of acute pancreatitis in a patient receiving vildagliptin.

METHODS

We present the clinical, biochemical, and radiographic findings of the study patient.

RESULTS

A 61-year-old woman who presented with severe abdominal pain was found to have acute pancreatitis. This occurred 5 weeks after the commencement of vildagliptin, a dipeptidyl-peptidase 4 inhibitor, for the treatment of type 2 diabetes mellitus. The patient's pancreatic enzymes were elevated (amylase, 1205 U/L; lipase, 8846 U/L), and abdominal computed tomography demonstrated diffuse pancreatic swelling, cyst formation, and necrosis in the body of the pancreas. In the absence of an identifiable cause for the patient's pancreatitis, vildagliptin was considered a potential trigger. The patient recovered after vildagliptin therapy was ceased.

CONCLUSIONS

Although incretin-based therapy effectively treats type 2 diabetes mellitus, emerging reports of acute pancreatitis in patients receiving sitagliptin and exenatide have prompted the US Food and Drug Administration to issue an alert on these drugs. This appears to be the first reported case of acute pancreatitis in a patient receiving vildagliptin, and it supports the possibility that acute pancreatitis may be a rare effect of incretin-based therapy.

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.

Pancreatitis, pancreatic, and thyroid cancer with glucagon-like peptide-1-based therapies

BACKGROUND & AIMS

Glucagon-like peptide-1-based therapy is gaining widespread use for type 2 diabetes, although there are concerns about risks for pancreatitis and pancreatic and thyroid cancers. There are also concerns that dipeptidyl peptidase-4 inhibitors could cause cancer, given their effects on immune function.

METHODS

We examined the US Food and Drug Administration's database of reported adverse events for those associated with the dipeptidyl peptidase-4 inhibitor sitagliptin and the glucagon-like peptide-1 mimetic exenatide, from 2004-2009; data on adverse events associated with 4 other medications were compared as controls. The primary outcomes measures were rates of reported pancreatitis, pancreatic and thyroid cancer, and all cancers associated with sitagliptin or exenatide, compared with other therapies.

RESULTS

Use of sitagliptin or exenatide increased the odds ratio for reported pancreatitis 6-fold as compared with other therapies (P<2×10(-16)). Pancreatic cancer was more commonly reported among patients who took sitagliptin or exenatide as compared with other therapies (P<.008, P<9×10(-5)). All other cancers occurred similarly among patients who took sitagliptin compared with other therapies (P=.20).

CONCLUSIONS

These data are consistent with case reports and animal studies indicating an increased risk for pancreatitis with glucagon-like peptide-1-based therapy. The findings also raise caution about the potential long-term actions of these drugs to promote pancreatic cancer.

A cohort study of acute pancreatitis in relation to exenatide use

AIM

Reports of acute pancreatitis associated with exenatide treatment prompted this study to estimate the association between acute pancreatitis and exenatide use relative to other antihyperglycaemic drugs.

METHODS

This cohort study included patients without claims for prior pancreatic disease who initiated exenatide or other antihyperglycaemic drugs between June 2005 and December 2007. Acute pancreatitis was identified with diagnosis codes and confirmed through review of blinded medical records. Poisson regression models provided estimates of rate ratios (RRs) and 95% confidence intervals (CIs) comparing the rate of acute pancreatitis during periods of current (days supplied + 31 days), recent (current definition + 31 days) and past use (≥32 days beyond current definition) of exenatide relative to other antihyperglycaemic drugs, adjusted for propensity scores. A prespecified nested case-control analysis provided RR estimates adjusted for patient characteristics abstracted from medical records.

RESULTS

Initiators of exenatide (N = 25719) had more baseline claims for obesity and concomitant diabetes drugs than comparators (N = 234536). There were 40 confirmed cases of acute pancreatitis in the exenatide cohort and 254 among other antihyperglycaemic drug initiators. Compared to other antihyperglycaemic drugs, the propensity score-adjusted RR for exenatide was 0.5 (95% CI 0.2-0.9) for current use, 1.1 (95% CI 0.4-3.2) for recent use and 2.8 (95% CI 1.6-4.7) for past use. The case-control analysis resulted in a RR of 0.2 for current use (95% CI 0.0-1.4) and 0.1 for recent use (95% CI 0.0-1.3), but an attenuated RR in the past use association (RR 1.1; 95% CI 0.1-11.0).

CONCLUSIONS

Exenatide use was not associated with an increased risk of acute pancreatitis.

What to add in with metformin in type 2 diabetes?

This review considers the therapeutic choices currently faced by people with type 2 diabetes and those caring for them when glucose levels initially controlled with lifestyle management and metformin start to rise. While sulphonylureas are familiar agents and cheaper than other alternatives, they cause hypoglycaemia and modest weight gain, and robust outcome data are still lacking. Dipeptidyl peptidase 4 inhibitors ('gliptins') have an attractive pharmacological and adverse effect profile, but their effects on the cardiovascular system are also uncertain. Thiazolidinediones ('glitazones') are effective glucose-lowering agents, but cause weight gain and increase the risk of fracture, while the cardiovascular benefits hoped for in association with 'insulin-sensitization' have not been as expected. Glucagon-like peptide-1 agonists will not be acceptable as initial second-line agents for many people as they are injectable rather than oral. Well-powered 'head-to-head' clinical trials of adequate duration are therefore required to allow evidence-based decisions on second-line therapy.

Dipeptidyl peptidase-4 inhibitors in the treatment of type 2 diabetes: a comparative review

The dipeptidyl peptidase (DPP)-4 inhibitors are a new class of antihyperglycaemic agents which were developed for the treatment of type 2 diabetes by rational drug design, based on an understanding of the underlying mechanism of action and knowledge of the structure of the target enzyme. Although they differ in terms of their chemistry, they are all small molecules which are orally available. There are some differences between them in terms of their absorption, distribution, metabolism and elimination, as well as in their potency and duration of action, but their efficacy, both in terms of inhibiting plasma DPP-4 activity and as antidiabetic agents, appears to be similar. They improve glycaemic control, reducing both fasting and postprandial glucose levels to lower HbA1c levels, without weight gain and with an apparently benign adverse event profile. At present, there seems to be little to distinguish between the different inhibitors in terms of their efficacy as antidiabetic agents and their safety. Long-term accumulated clinical experience will reveal whether compound-related characteristics lead to any clinically relevant differences.

Glucagon-like peptide analogues for type 2 diabetes mellitus: systematic review and meta-analysis

BACKGROUND

Glucagon-like peptide (GLP-1) analogues are a new class of drugs used in the treatment of type 2 diabetes. They are given by injection, and regulate glucose levels by stimulating glucose-dependent insulin secretion and biosynthesis, suppressing glucagon secretion, and delaying gastric emptying and promoting satiety. This systematic review aims to provide evidence on the clinical effectiveness of the GLP-1 agonists in patients not achieving satisfactory glycaemic control with one or more oral glucose lowering drugs.

METHODS

MEDLINE, EMBASE, the Cochrane Library and Web of Science were searched to find the relevant papers. We identified 28 randomised controlled trials comparing GLP-1 analogues with placebo, other glucose-lowering agents, or another GLP-1 analogue, in patients with type 2 diabetes with inadequate control on a single oral agent, or on dual therapy. Primary outcomes included HbA1c, weight change and adverse events.

RESULTS

Studies were mostly of short duration, usually 26 weeks. All GLP-1 agonists reduced HbA1c by about 1% compared to placebo. Exenatide twice daily and insulin gave similar reductions in HbA1c, but exenatide 2 mg once weekly and liraglutide 1.8 mg daily reduced it by 0.20% and 0.30% respectively more than glargine. Liraglutide 1.2 mg daily reduced HbA1c by 0.34% more than sitagliptin 100 mg daily. Exenatide and liraglutide gave similar improvements in HbA1c to sulphonylureas. Exenatide 2 mg weekly and liraglutide 1.8 mg daily reduced HbA1c by more than exenatide 10 μg twice daily and sitagliptin 100 mg daily. Exenatide 2 mg weekly reduced HbA1c by 0.3% more than pioglitazone 45 mg daily.Exenatide and liraglutide resulted in greater weight loss (from 2.3 to 5.5 kg) than active comparators. This was not due simply to nausea. Hypoglycaemia was uncommon, except when combined with a sulphonylurea. The commonest adverse events with all GLP-1 agonists were initial nausea and vomiting. The GLP-1 agonists have some effect on beta-cell function, but this is not sustained after the drug is stopped.

CONCLUSIONS

GLP-1 agonists are effective in improving glycaemic control and promoting weight loss.

Diabetes and cancer

Diabetes and cancer are common conditions, and their co-diagnosis in the same individual is not infrequent. A link between the two conditions has been postulated for almost 80 years, but only in the past decade has significant epidemiological evidence been amassed to suggest that diabetes and cancer are associated, and the link appears causal. Hyperinsulinaemia, adipocytokines, growth factors and epigenetic changes may be implicated in the pathogenesis of cancer amongst patients with diabetes, and recently, diabetes therapies have also been implicated. There is reasonable circumstantial evidence that metformin may decrease the risk of cancer amongst diabetic patients. Much more research is required to elucidate the link between diabetes and cancer, particularly the potential link with diabetes treatments.

An assessment of adverse effects of vildagliptin versus comparators on the liver, the pancreas, the immune system, the skin and in patients with impaired renal function from a large pooled database of Phase II and III clinical trials

AIM

To assess the safety of vildagliptin versus all comparators (ACs) with regard to organs, systems or tissues of particular interest in type 2 diabetes (T2DM) and areas of potential concern with dipeptidyl peptidase-IV (DPP-4) inhibitors.

METHODS

Data were pooled from 38 studies where vildagliptin was given for > or =12 to > 104 weeks in patients with T2DM. Absolute and exposure-adjusted incidence rates and Peto odds ratios (ORs) versus ACs with corresponding 95% confidence intervals (CI) were calculated.

RESULTS

There were > 7000 subject-years of exposure (SYE) to vildagliptin 50 mg bid and > 6500 SYE to ACs. For mild hepatic enzyme elevations with and without elevated bilirubin levels, the ORs for vildagliptin 50 mg bid were 1.24 (95% CI: [0.80, 1.93]) and 1.19 (95% CI: [0.29, 4.90]), respectively. The exposure-adjusted incidences of markedly elevated hepatic enzymes and for enzyme elevations with bilirubin > or = 2x ULN with vildagliptin 50 mg bid were < or = those in the ACs group. For hepatic and pancreatitis-related AEs, the ORs for vildagliptin 50 mg bid were 0.87 (95% CI: [0.64, 1.19]) and 0.70 (95% CI: [0.26, 1.88]), respectively, and for any AE in the infections and infestations SOC, this was 1.04 (95% CI: [0.96, 1.13]). The incidences of skin-related AEs were low and the risk with vildagliptin 50 mg bid was not significantly different from ACs [(OR = 1.10 (95% CI: [0.80, 1.51])].

CONCLUSIONS

The present meta-analyses indicate that vildagliptin was not associated with increased risk of hepatic events or hepatic enzyme elevations indicative of drug-induced liver injury, pancreatitis, infections or skin-related toxicity.