Dipeptidyl peptidase IV inhibitors as new therapeutic agents for the treatment of Type 2 diabetes

Type 2 diabetes is the most prevalent form of diabetes. Incretin hormones play an important role in normal and pathological blood glucose homeostasis. The role of dipeptidyl peptidase IV (DPP IV) in the inactivation of glucagon-like peptide-1 (GLP-1), one of the most important incretins, is wellestablished. Therefore, DPP IV inhibitors are investigated as new therapeutic agents for the treatment of Type 2 diabetes. A summary of DPP IV inhibitors reported until 1998 and a more extensive discussion of more recent inhibitors found in literature and patent applications will be provided. The therapeutic potential of several aminoacyl pyrrolidides, aminoacyl thiazolidides and aminoacyl pyrrolidine-2-nitriles will be reviewed.     

Management of Type 2 diabetes: the role of incretin mimetics

Type 2 diabetes is characterised by insulin resistance and progressive β-cell dysfunction (which leads to hyperglycaemia), the risk of progressive worsening of glycaemic control and an increased risk of both macrovascular and microvascular complications. Existing treatment strategies target deficient insulin secretion and insulin resistance, but do not generally address the underlying progressive β-cell dysfunction that is common to Type 2 diabetes. Traditionally, Type 2 diabetes is first treated with medical nutrition therapy (reduced food intake and increased physical activity), followed by stepwise addition of oral antidiabetes therapies and, ultimately, exogenous insulin, as required. Unfortunately, these approaches have not been shown to delay the need for additional therapies, nor do they generally prevent or delay the inexorable decline in β-cell function. Patients with Type 2 diabetes commonly experience deterioration in glycaemic control, and may have substantial weight gain due to the diabetes therapies that contribute to worsening obesity. In addition, insulin-providing therapies, such as sulfonylureas and exogenous insulin, carry the risk of hypoglycaemia, and cannot fully address the complex hormonal irregularities that characterise Type 2 diabetes, including the role of glucagon hypersecretion. New therapeutic approaches are being developed that couple durable glycaemic control with improved control of body weight. These approaches include development of the incretin mimetics, which are a novel class of agents that share several of the glucoregulatory effects of incretin hormones, such as glucagon-like hormone-1. Deficiency of glucagon-like hormone-1 secretion is known to be present in those with abnormal glucose tolerance. Agents that manipulate the physiological actions of incretin hormones, such as glucagon-like hormone-1, may significantly benefit patients with Type 2 diabetes.     

Novel N-substituted-2-cyanopyrrolidines as potent inhibitors of dipeptidyl peptidase IV in the treatment of non-insulin-dependent diabetes mellitus

This is the second patent application from Novartis describing N-substituted-2-cyanopyrrolidines as inhibitors of dipeptidyl peptidase IV (DPP-IV). DPP-IV is a serine protease which cleaves Xaa-Pro- or Xaa-Ala- amino terminal sequences from biologically active peptides, transforming them into inactive or even antagonistic species. Among them is glucagon-like peptide 1 (GLP-1), a major stimulator of pancreatic insulin secretion with additional properties in lowering the blood glucose level, which is normally secreted in response to food ingestion. By inhibiting DPP-IV the endogenous GLP-1 is preserved for longer periods, the inhibitors being useful in the treatment of the non-insulin-dependent diabetes mellitus (NIDDM), obesity, arthritis, osteoporosis and other diseases generated or enhanced by impaired glucose tolerance. The compounds claimed in this application are novel N-substituted 2-cyanopyrrolidines bearing adamantyl moieties as biocompatible lipophylic groups; their low nanomolar level of DPP-IV inhibition, as well as their in vivo therapeutic profile, are improved as compared with the results obtained in previous studies.     

Network meta-analysis of liraglutide versus dipeptidyl peptidase-4 inhibitors for the treatment of type 2 diabetes in Japanese patients

Aims: To determine the comparative efficacy and safety of liraglutide and dipeptidyl peptidase-4 (DPP-4) inhibitors as antidiabetics for Japanese patients with uncontrolled type 2 diabetes (T2DM).

Methods and materials: We searched for randomized controlled trials (RCTs) evaluating outcomes among Japanese adults with uncontrolled T2DM and including liraglutide or DPP-4 inhibitors up to August 2016. We extracted data on trial and patient characteristics, and the following outcomes: HbA1c, weight, patients meeting HbA1c <7%, patients experiencing hypoglycemic events, microalbuminuria, estimated glomerular filtration rate (eGFR) and creatinine. We synthesized data using network meta-analyses (NMA) using a Bayesian framework. Continuous outcomes were modeled using normal likelihoods and an identity link, while dichotomous outcomes were modeled using a binomial likelihood and a logit link.

Results: The systematic literature review yielded 39 publications pertaining to 38 trials. A total of 27 trials (5032 patients) reported change in HbA1c at 12 weeks and at 24 weeks 9 trials (2091 patients). All treatments showed statistically significant reductions in HbA1c relative to placebo at 12 and 24 weeks. Liraglutide 0.9?mg was statistically superior to all DPP-4 interventions (vildagliptin, sitagliptin, linagliptin, alogliptin, teneligliptin, trelagliptin and omarigliptin) at 12 weeks and 24 weeks among those reporting. Treatments were not statistically differentiable with respect to weight change and risk of hypoglycemia. Finally, no comparisons of eGFR and microalbuminuria were conducted, as this data was reported in too few trials to conduct analyses.

Limitations: Some important outcomes were limited by poor reporting (eGFR and microalbuminuria) or low event rates (hypoglycemia). The follow-up time was relatively short. Clinically, the 24 week time point is more important as it demonstrates more sustained results.

Conclusions: Our research suggests that liraglutide 0.9?mg offers a more efficacious treatment option for T2DM than the DPP-4 inhibitors among adult Japanese patients and that it is a viable option for this population.     

Diabetes: the latest developments in inhibitors,insulin sensitisers,new drug targets and novel approaches

The 6th annual conference on diabetes, organised by the SMI group, was held on 18th – 19th October 2004 in London, followed by a one-day symposium on an executive briefing entitled Type 2 diabetes and beyond: the untapped commercial potential. More than 100 delegates from both academic and industrial institutes attended the two meetings. The presentations provided insights into the understanding of mechanisms and developments of novel drugs for treatments of insulin resistance, diabetes, and metabolic syndrome, as well as new approaches for therapeutic intervention including the development of dipeptidyl peptidase IV inhibitors and glucagon-like peptide-1 analogues. This review offers a general overview of the fields in metabolic diseases and different strategies to develop new drugs. Discussions focused on several emerging therapeutic areas, including novel compound developments and target identification with the use of conventional methods and recently emerged technologies, such as siRNA, genomics and pro-teomics.     

Vildagliptin: the evidence for its place in the treatment of type 2 diabetes mellitus

Introduction:

Type 2 diabetes is increasing in prevalence worldwide and is a leading cause of morbidity and mortality, mainly due to the development of complications. Vildagliptin is an inhibitor of dipeptidyl peptidase 4 (DPP-4), a new class of oral antidiabetic agents.

Aims:

To evaluate the role of vildagliptin in the management of type 2 diabetes.

Evidence review:

Clear evidence shows that vildagliptin improves glycemic control (measured by glycosylated hemoglobin and blood glucose levels) more than placebo in adults with type 2 diabetes, either as monotherapy or in combination with metformin. Vildagliptin is as effective as pioglitazone and rosiglitazone, and slightly less effective than metformin, although better tolerated. Further glycemic control is achieved when adding vildagliptin to metformin, pioglitazone, or glimepride. There is evidence that vildagliptin improves beta-cell function and insulin sensitivity. Vildagliptin does not appear to be associated with weight gain or with a higher risk of hypoglycemia than placebo or other commonly used oral antidiabetic agents. Economic evidence is currently lacking.

Place in therapy:

Vildagliptin improves glycemic control with little if any weight gain or hypoglycemia in adult patients with type 2 diabetes when given alone or in combination with metformin, thiazolidinediones, or sulfonylureas. Since many diabetic patients require combination therapy, the complementary mechanism of action of vildagliptin and other commonly prescribed antidiabetic drugs represents an important new therapeutic option in diabetes management.     

Inhibitors of proline-specific dipeptidyl peptidases: DPP IV inhibitors as a novel approach for the treatment of Type 2 diabetes

Dipeptidyl peptidase IV (DPP IV) is a validated target for the treatment of Type 2 diabetes, with several inhibitors currently in Phase III clinical trials. This review will mainly focus on DPP IV inhibitors that were published in scientific literature and patents after 2002. Medicinal chemistry aspects of several classes of inhibitors are described with respect to inhibitory potency, selectivity over DPP8, DPP9, FAPα and DPP II, stability and ADME/Tox issues. Although the main part of this review is on potent and selective DPP IV inhibitors, selective inhibitors for the related proline-specific dipeptidyl peptidases will be described.     

Empagliflozin for the treatment of Type 2 diabetes

Diabetes and its complications account for a significant healthcare burden. There is increasing prevalence of diabetes and newer drugs are being investigated to improve outcomes. Sodium–glucose cotransporter inhibitors (SGLT2 inhibitors) are a newer class of medications, which prevent renal reabsorption of glucose and hence help in glycaemic control without significant risk of hypoglycaemia. Two drugs, namely dapagliflozin and canagliflozin have gained approval and empagliflozin is one of the advanced agents of this class. Early trials with empagliflozin have shown a stable pharmacokinetic profile and pharmacodynamic effects with significant SGLT2 selectivity. Clinical trials have shown improvement in glycaemic control and other benefits including weight loss and lowering of blood pressure. Ongoing trials and surveillance will provide answers about cardiovascular benefits, risk of osteoporosis and cancer.     

Safety evaluation of trelagliptin in the treatment of Japanese type 2 diabetes mellitus patients

Introduction: Trelagliptin is a novel, long-acting dipeptidyl peptidase-4 (DPP-4) inhibitor approved for the treatment of type 2 diabetes mellitus (T2DM) in japan. The safety and efficacy of trelagliptin has been evaluated in three published clinical trials to date: one phase II and two phase III studies. As trelagliptin only requires dosing once per week, this new agent has the potential to improve compliance and subsequently, glycaemic control, in patients with T2DM.

Areas covered: This article reviews the available safety data for trelagliptin from published clinical trials, and evaluates the published safety profile relative to competitor once-daily and once-weekly DPP-4 inhibitors.

Expert opinion: Clinical trial data to date suggest that trelagliptin is a safe and efficacious medication with a similar safety profile to once-daily DPP-4 inhibitors, and to the once-weekly DPP-4 inhibitor, omarigliptin. Trelagliptin is well tolerated when given alone, and in combination with other anti-diabetic medications. An advantage of trelagliptin over existing once-daily DPP-4 inhibitors is the decrease of dosing frequency, rather than once-daily. No specific, serious adverse events have been reported for trelagliptin in published clinical trials, making it an attractive alternative to other DPP-4 inhibitors.     

Glucose-6-phosphatase inhibitors for the treatment of Type 2 diabetes

Much biological knowledge has been gained over the years as to the role of glucose-6-phosphatase, (G-6-pase), enzyme complex in glucose homeostasis and in Type 2 diabetes. Glucose-6-phosphatase is mainly located in the liver and catalyses the terminal step in both gluconeogenesis and glycogenolysis. Another interesting feature is that the enzyme activity is several fold higher in diabetic animals and probably also in diabetic humans and therefore could be an important key player in the elevated hepatic glucose production seen in Type 2 diabetes. During the last nine years substantial efforts have been made, primarily by scientists at Hoechst (now Aventis) and Novo Nordisk, in order to discover novel compounds which inhibit the glucose-6-phosphatase enzyme complex and could be applied therapeutically in the treatment of Type 2 diabetes. These compounds, as well as other compounds published with inhibitory action on glucose-6-phosphatase, are reviewed. No compounds yet have been reported to be in clinical development.     

Incretin mimetics and dipeptidyl peptidase 4 inhibitors in clinical trials for the treatment of type 2 diabetes

Background: Exenatide is an incretin mimetic, while sitagliptin and vildagliptin are incretin enhancers used as adjunctive therapy in patients with type 2 diabetes failing oral agents. Sitagliptin and vildagliptin can also be used as monotherapy in patients with type 2 diabetes uncontrolled by diet. Objective: To provide a critical review of clinical trials of exenatide, sitagliptin and vildagliptin. Method: Review of Phase III clinical trials based on Medline search published up to April 2008. Results: The use of exenatide is associated with reduction in average hemoglobin A1c (HbA1c) levels of approximately 0.8% compared with baseline. The corresponding reduction with either sitagliptin or vildagliptin is 0.7%. The actions of incretin-based drugs predominantly target postprandial hyperglycemia. Treatment-related hypoglycemia is generally mild, and mainly occurs when used with sulfonylureas (SUs). Exenatide treatment leads to a mild weight loss of around 2 kg after 30 weeks, whereas sitagliptin and vildagliptin have generally neutral effect on weight. Sitagliptin and vildagliptin are well tolerated in trials lasting up to 52 weeks. Meanwhile, 5 – 10% of patients cannot tolerate exenatide due to adverse effects, mainly nausea and vomiting. The three drugs are limited by the lack of long-term safety and efficacy data, as well as by their high cost. Conclusion: Exenatide, sitagliptin and vildagliptin are useful add-on therapy for type 2 diabetes that is suboptimally controlled on oral agents, particularly when there is concern about weight gain and hypoglycemia, or when postprandial hyperglycemia is the major cause of inadequate glycemic control. Sitagliptin and vildagliptin may be used as monotherapy in patients who cannot tolerate metformin or SU, and sitagliptin may be used as alternative to metformin in renal insufficiency.     

胰高血糖素样肽-1受体激动剂与钠-葡萄糖协同转运蛋白-2抑制剂治疗2型糖尿病疗效及安全性的系统评价

目的：系统评价胰高血糖素样肽-1受体激动剂（GLP-1RA）与钠-葡萄糖协同转运蛋白-2抑制剂（SGLT-2i）治疗2型糖尿病（T2DM）的疗效及安全性,为临床治疗提供循证参考。方法：计算机检索相关的随机对照试验。采用Stata 14.0软件进行Meta分析,并运用成本-效果分析方法进行短期经济学评价。结果：共纳入6项RCT,合计2 248例患者,纳入药物包括利拉鲁肽、艾塞那肽、司美格鲁肽、卡格列净、达格列净和恩格列净。Meta分析结果显示：GLP-1RA能更有效地降低糖化血红蛋白（HbA1c）水平[SMD=-0.28,95% CI （-0.40,-0.16）,P<0.01],且HbA1c<7%的达标率更高,而SGLT-2i能更有效地控制患者的收缩压、舒张压和脉搏;GLP-1RA治疗组导致停药、腹泻、恶心、呕吐等不良反应的发生率均显著高于SGLT-2i治疗组,而SGLT-2i治疗组患者出现生殖器感染的发生率更高,差异均有统计学意义。SGLT-2i的成本-效果比更低。结论：GLP-1RA降低T2DM患者HbA1c水平的疗效更好,但SGLT-2i控制患者血压和脉搏的效果更优、耐受性更佳且具有较高的经济学优势,临床治疗中应根据患者的具体情况选择合适的药物。     

Investigational therapies in the treatment of obesity

Obesity is a major public health concern and environmental factors are involved in its development. The hypothalamus is a primary site for the integration of signals for the regulation of energy homeostasis. Dysregulation of these pathways can lead to weight loss or gain. Some drugs in development can have favourable effects on body weight, acting on some of these pathways and leading to responses resulting in weight loss. Strategies for the management of weight reduction include exercise, diet, behavioural therapy, drug therapy and surgery. Investigational antiobesity medications can modulate energy homeostasis by stimulating catabolic or inhibiting anabolic pathways. Investigational drugs stimulating catabolic pathways consist of leptin, agonists of melanocortin receptor-4, 5-HT and dopamine; bupropion, growth hormone fragments, cholecystokinin subtype 1 receptor agonist, peptide YY_3-36, oxyntomodulin, ciliary neurotrophic factor analogue, β3-adrenergic receptor agonists, adiponectin derivatives and glucagon-like peptide-1. On the other hand, investigational drugs inhibiting anabolic pathways consist of the ghrelin receptor, neuropeptide Y receptor and melanin-concentrating hormone-1 antagonists; somatostatin analogues, peroxisome proliferator-activated receptor-γ and -β/δ antagonists, gastric emptying retardation agents, pancreatic lipase inhibitors, topiramate and cannabinoid-1 receptor antagonists. These differing approaches are reviewed and commented on in this article.     

西格列汀对初发2型糖尿病患者胰岛B细胞功能的影响

目的研究西格列汀对初发2型糖尿病患者胰岛B细胞功能的影响。方法选择我院门诊2型糖尿病患者69例,随机分为对照组和试验组,对照组35例,试验组34例,对照组予二甲双胍治疗,试验组予二甲双胍、西格列汀治疗,12周后比较治疗前后两组患者空腹血糖(FPG)、餐后2 h血糖(PPG)、糖化血红蛋白(Hb A1c)、体重指数(BMI)、空腹胰岛素(Fins)、餐后2 h胰岛素(Pins)。结果两组治疗前各项指标比较差异无统计学意义(P>0.05),治疗后,两组FPG、PPG、Hb A1c、BMI均较治疗前显著下降(P<0.05)。与对照组相比,试验组FPG、PPG、Hb A1c降低更明显(P<0.05),Fins、Pins水平升高更显著(P<0.05)。结论西格列汀能明显改善初发2型糖尿病患者的胰岛B细胞功能,在临床应用中安全有效。     

Medically minimising the impact of hypoglycaemia in type 2 diabetes: a review

Introduction: Some therapies for type 2 diabetes (T2DM) are limited by hypoglycaemia, and this underestimated side effect carries an associated morbidity and financial burden. Large trials that have examined strict glycaemic control and cardiovascular outcomes in T2DM have highlighted the potential harm of exposure to hypoglycaemia in people with coronary heart disease.

Areas covered: The responses to, and the morbidity associated with, hypoglycaemia in T2DM are discussed with identification of people most at risk of severe hypoglycaemia. The evidence base for non-pharmacological strategies and the risks of hypoglycaemia associated with various treatment modalities are examined. This review provides the clinician with a rational approach to the selection of different anti-diabetes drugs to minimize the risk of hypoglycaemia.

Expert opinion: When managing T2DM, insulin and insulin secretagogues should be used judiciously and glycaemic targets individualized to avoid hypoglycaemia. Incretin mimetics present a lower risk of hypoglycaemia with similar efficacy as traditional agents in treating hyperglycaemia. The potential relationship between hypoglycaemia and precipitation of acute cardiovascular events is a highly topical area of research and may help determine what glycaemic targets are appropriate in people with T2DM.     

Thiazolidinediones in the treatment of Type 2 diabetes

In the last few years there has been an explosion of research that has improved our understanding of the pathogenesis of Type 2 diabetes mellitus (DM-2) and has led to the development of new oral antidiabetic drugs. Thiazolidinediones (TZDs) are the newest of these antidiabetic agents. TZDs are insulin sensitisers that depend on the presence of insulin for their action. They target insulin resistance, which is thought to play a central role in DM-2 and the associated metabolic syndrome characterised by central obesity, hypertension, dyslipidemia and hypercoagulability, all leading to increased cardiovascular morbidity and mortality. As a result, TZDs have the potential to improve other conditions associated with the metabolic syndrome, in addition to their glycaemic action. TZDs act by activating peroxisome proliferator-activated receptor (PPAR) γ, a nuclear receptor implicated not only in lipid and glucose metabolism but other physiological functions as well. TZDs may have wide clinical applications beyond DM-2, as they can potentially be used to treat other conditions associated with insulin resistance and PPAR-γ receptors, such as impaired glucose tolerance, polycystic ovarian syndrome and HIV lipodystrophy.     

Inhibition of dipeptidyl peptidase 4 by BI-1356, a new drug for the treatment of beta-cell failure in type 2 diabetes

BI 1356, a xanthine-based DPP-4 inhibitor, has reached Phase III trials. The compound efficiently inhibits dipeptidyl peptidase 4 (DPP-4) in vitro and in vivo. In vivo GLP-1 levels increase to levels at or above the levels of other DPP-4 inhibitors. Preclinical trials suggest a once-daily administration of 5 mg to be efficient, long-lasting and without known side effects.     

Therapeutic potential of ACE inhibitors for the treatment of hypertension in Type 2 diabetes

Type 2 diabetes mellitus is associated with hypertension. If untreated, hypertension has a major impact on the clinical course of Type 2 diabetes and its vascular complications. In this review, we discuss rationale for the use of ACE inhibitors (ACEI) in hypertensive Type 2 diabetic patients and compare those theoretical assumptions with results of recent major clinical trials. Furthermore, possible directions for future clinical and experimental research are outlined. The RAS and its effector angiotensin II are important players in a number of cardiovascular and renal disorders. Recent evidence suggests that RAS and factors functionally linked to RAS are activated in Type 2 diabetes. Therefore, there is a theoretical basis for the use of ACEI in the treatment of hypertension in diabetic patients. Some recent studies reported superior outcome in patients treated with ACEI-based antihypertensive regimens compared with non-ACEI based treatments in reducing the risk of macrovascular disease (CAPPP, FACET, ABCD) or both micro- and macrovascular complications in Type 2 diabetes (HOPE). However, at least two of the large prospective studies discussed in this review (UKPDS 38, HOT), supported by results from previously published SHEP study, have recently suggested that the degree of reduction of blood pressure, rather than the choice of a particular class of antihypertensive agent, is associated with decreased risk of cardiovascular events. Studies focusing on renal end-points suggest that ACEI have a superior antiproteinuric effect than the other agents. However, whether ACEI are more nephroprotective, as assessed by the rate of decline in renal function, still remains to be elucidated. Despite promising results from recent trials, large numbers of patients progress despite ACEI treatment. Incomplete inhibition of the RAS may underlie this phenomenon. Treatment strategies that could enhance the degree of RAS inhibition represent one possible direction for clinical research in the near future. However, it is unlikely that the course of such a complex syndrome as Type 2 diabetes could be dramatically changed by just one class of antihypertensive agents. This goal is more likely to be achieved by multifactorial intervention, reflecting the complexity of metabolic syndrome. ACEI should be viewed as an important, but not the only, part of this complex approach.