Linagliptin, a dipeptidyl peptidase-4 inhibitor with a unique pharmacological profile, and efficacy in a broad range of patients with type 2 diabetes

Development of Long-Acting Dipeptidyl Peptidase-4 Inhibitors: Structural Evolution and Long-Acting Determinants

Considerable effort has been made to achieve less frequent dosing in the development of DPP-4 inhibitors. Enthusiasm for long-acting DPP-4 inhibitors is based on the promise that such agents with less frequent dosing regimens are associated with improved patient adherence, but the rational design of long-acting DPP-4 inhibitors remains a major challenge. In this Perspective, the development of long-acting DPP-4 inhibitors is comprehensively summarized to highlight the evolution of initial lead compounds on the path toward developing long-acting DPP-4 inhibitors over nearly three decades. The determinants for long duration of action are then examined, including the nature of the target, potency, binding kinetics, crystal structures, selectivity, and preclinical and clinical pharmacokinetic and pharmacodynamic profiles. More importantly, several possible approaches for the rational design of long-acting drugs are discussed. We hope that this information will facilitate the design and development of safer and more effective long-acting DPP-4 inhibitors and other oral drugs.

Role of dipeptidyl peptidase 4 inhibitors in the new era of antidiabetic treatment

The last few years important changes have occurred in the field of diabetes treatment. The priority in the therapy of patients with diabetes is not glycemic control per se rather an overall management of risk factors, while individualization of glycemic target is suggested. Furthermore, regulatory authorities now require evidence of cardiovascular (CV) safety in order to approve new antidiabetic agents. The most novel drug classes, i.e., sodium-glucose transporter 2 inhibitors (SGLT2-i) and some glucagon-like peptide-1 receptor agonists (GLP-1 RA), have been demonstrated to reduce major adverse CV events and, thus, have a prominent position in the therapeutic algorithm of hyperglycemia. In this context, the role of previously used hypoglycemic agents, including dipeptidyl peptidase 4 (DPP-4) inhibitors, has been modified. DPP-4 inhibitors have a favorable safety profile, do not cause hypoglycemia or weight gain and do not require dose uptitration. Furthermore, they can be administered in patients with chronic kidney disease after dose modification and elderly patients with diabetes. Still, though, they have been undermined to a third line therapeutic choice as they have not been shown to reduce CV events as is the case with SGLT2-i and GLP-1 RA. Overall, DPP-4 inhibitors appear to have a place in the management of patients with diabetes as a safe class of oral glucose lowering agents with great experience in their use.

Electrochemical C-H Functionalization of (Hetero)Arenes-Optimized by DoE

A novel approach towards the activation of different arenes and purines including caffeine and theophylline is presented. The simple, safe and scalable electrochemical synthesis of 1,1,1,3,3,3‐hexafluoroisopropanol (HFIP) aryl ethers was conducted using an easy electrolysis setup with boron‐doped diamond (BDD) electrodes. Good yields up to 59 % were achieved. Triethylamine was used as a base as it forms a highly conductive media with HFIP, making additional supporting electrolytes superfluous. The synthesis was optimized using Design of Experiment (DoE) techniques giving a detailed insight to the significance of the reaction parameters. The mechanism was investigated by cyclic voltammetry (CV). Subsequent transition metal‐catalyzed as well as metal‐free functionalization led to interesting motifs in excellent yields up to 94 %.

Structural re-positioning, in silico molecular modelling, oxidative degradation, and biological screening of linagliptin as adenosine 3 receptor (ADORA3) modulators targeting hepatocellular carcinoma

Chemical entities with structural diversity were introduced as candidates targeting adenosine receptor with different clinical activities, containing 3,7-dihydro-1H-purine-2,6-dione, especially adenosine 3 receptors (ADORA3). Our initial approach started with pharmacophore screening of ADORA3 modulators; to choose linagliptin (LIN), approved anti-diabetic drug as Dipeptidyl peptidase-4 inhibitors, to be studied for its modulating effect towards ADORA3. This was followed by generation, purification, analytical method development, and structural elucidation of oxidative degraded product (DEG). Both of LIN and DEG showed inhibitory profile against hepatocellular carcinoma cell lines with induction of apoptosis at G2/M phase with increase in caspase-3 levels, accompanied by a downregulation in gene and protein expression levels of ADORA3 with a subsequent increase in cAMP. Quantitative in vitro assessment of LIN binding affinity against ADORA3 was also performed to exhibit inhibitory profile at Ki of 37.7 nM. In silico molecular modelling showing binding affinity of LIN and DEG towards ADORA3 was conducted.

Comparison of the effects of linagliptin and voglibose on endothelial function in patients with type 2 diabetes and coronary artery disease: a prospective, randomized, pilot study (EFFORT)

Endothelial dysfunction contributes to poor cardiovascular prognosis in patients with type 2 diabetes mellitus (T2DM) and coronary artery disease (CAD). The effect of dipeptidyl peptidase-4 inhibitors on endothelial function remains controversial. We sought to compare the effects of linagliptin and voglibose on endothelial function, as assessed by reactive hyperemia-peripheral arterial tonometry (RH-PAT). Sixteen patients with newly diagnosed T2DM and CAD were randomized 1:1 to linagliptin (5 mg, once-daily) or voglibose (0.9 mg, thrice-daily). The RH-PAT and laboratory parameters, including 75 g oral glucose tolerance test, were measured at baseline and 3 months. Linagliptin increased serum levels of active glucagon-like peptide-1 and high-molecular-weight adiponectin. Age-, sex-, and baseline-adjusted changes in logarithmic RH-PAT index (LnRHI) after 3 months were significant between groups (linagliptin, 0.135 ± 0.097; voglibose, - 0.124 ± 0.091; P = 0.047). In the linagliptin group, change in LnRHI was positively correlated with change in high-density lipoprotein cholesterol and negatively correlated with changes in both urine albumin-to-creatinine ratio and high-sensitivity C-reactive protein. Furthermore, linagliptin treatment for 3 months reduced serum levels of both glucose and insulin at 2 h, relative to voglibose, in the age-, sex-, and baseline-adjusted model. Linagliptin improved endothelial function relative to voglibose, accompanied by amelioration of glycemic, renal, and cardiometabolic parameters, in patients with newly diagnosed T2DM and CAD.Trial registration Unique Trial Number, UMIN 000029169 ( https://upload.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000012442 ).

Incretin-based therapy for type 2 diabetes mellitus is promising for treating neurodegenerative diseases

Incretin hormones include glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP). Due to their promising action on insulinotropic secretion and improving insulin resistance (IR), incretin-based therapies have become a new class of antidiabetic agents for the treatment of type 2 diabetes mellitus (T2DM). Recently, the links between neurodegenerative diseases and T2DM have been identified in a number of studies, which suggested that shared mechanisms, such as insulin dysregulation or IR, may underlie these conditions. Therefore, the effects of incretins in neurodegenerative diseases have been extensively investigated. Protease-resistant long-lasting GLP-1 mimetics such as lixisenatide, liraglutide, and exenatide not only have demonstrated promising effects for treating neurodegenerative diseases in preclinical studies but also have shown first positive results in Alzheimer's disease (AD) and Parkinson's disease (PD) patients in clinical trials. Furthermore, the effects of other related incretin-based therapies such as GIP agonists, dipeptidyl peptidase-IV (DPP-IV) inhibitors, oxyntomodulin (OXM), dual GLP-1/GIP, and triple GLP-1/GIP/glucagon receptor agonists on neurodegenerative diseases have been tested in preclinical studies. Incretin-based therapies are a promising approach for treating neurodegenerative diseases.

A safety evaluation of empagliflozin plus linagliptin for treating type 2 diabetes

INTRODUCTION

Dipeptidyl-peptidase-IV inhibitors (DPP-4i) and sodium-glucose-transporter-2 inhibitors (SGLT-2i) are oral antidiabetic drugs that improve glycemic parameters and possess a very low intrinsic hypoglycemia risk and favorable cardiovascular data. Areas covered: An overview on the clinical studies investigating the combination therapy with the DPP-4i linagliptin and the SGLT-2i empagliflozin is given. The clinical evidence for the efficacy and safety of free combinations as well as for their fixed dose combinations is presented. Empagliflozin has recently proved to reduce cardiovascular risk in type 2 diabetes and cardiovascular high risk situations. A fixed dose combination (FDC) of empagliflozin and linagliptin as add on therapy to metformin or as initial treatment lowered the HbA1c by approximately 1.1% and reduced the body weight by 2.0-3.0 kg. The hypoglycemia risk was not significantly increased. The relevant studies were identified by a search in Medline and in clinicaltrials.gov. Expert opinion/commentary: A DPP-4i/SGLT-2i FDC may be especially useful to simplify treatment, to reduce the tablet burden and to increase medication adherence. This FDC may be particularly beneficial for patients where the reduction of body weight, blood pressure and cardiovascular risk are important and in whom hypoglycemia should be avoided.

Effects of Linagliptin on Pancreatic α Cells of Type 1 Diabetic Mice

The dipeptidyl peptidase-4 inhibitor linagliptin promotes β-cell survival and insulin secretion by prolonging endogenous glucagon-like peptide 1 (GLP-1) action and therefore helps to maintain normoglycemia in diabetic patients. The effect of linagliptin on glucagon-producing α cells, however, was not clear. In this study, we investigated whether linagliptin had any effects on α cells with regard to their proliferation and hormonal production using type 1 diabetes mouse models, including streptozotocin-induced and nonobese diabetes mice. After diabetes development, the mice were either untreated or treated with linagliptin or insulin for up to 6 weeks. Our results showed that linagliptin significantly increased circulating GLP-1 levels in both type 1 diabetes models, but therapeutic benefit was detected in nonobese diabetes mice only. Circulating C-peptide and glucagon levels (nonfasting) were not significantly altered by linagliptin treatment in either model. In addition, we found that linagliptin did not increase α-cell proliferation compared with the untreated or insulin-treated controls as assessed by in vivo 5-bromo-2'-deoxyuridine labeling assay. Finally, we examined whether linagliptin treatment altered GLP-1 vs glucagon expression in pancreatic α cells. Immunohistochemistry assays showed that linagliptin treatment resulted in detection of GLP-1 in more α cells than in control groups, suggesting linagliptin was able to increase intraislet GLP-1 presence, presumably by inhibiting GLP-1 degradation. In summary, this study indicates that linagliptin would not confer adverse effect on α cells, such as causing α cell hyperplasia, and instead may facilitate a blood glucose-lowering effect by increasing GLP-1 presence in α cells.

Differential Effects of Linagliptin on the Function of Human Islets Isolated from Non-diabetic and Diabetic Donors

Linagliptin is a dipeptidyl Peptidase-4 (DPP-4) inhibitor that inhibits the degradation of glucagon-like peptide 1 (GLP-1), and has been approved for the treatment of type 2 diabetes (T2D) in clinic. Previous studies have shown linagliptin improves β cell function using animal models and isolated islets from normal subjects. Since β cell dysfunction occurs during diabetes development, it was not clear how human islets of T2D patients would respond to linagliptin treatment. Therefore, in this study we employed human islets isolated from donors with and without T2D and evaluated how they responded to linagliptin treatment. Our data showed that linagliptin significantly improved glucose-stimulated insulin secretion for both non-diabetic and diabetic human islets, but its effectiveness on T2D islets was lower than on normal islets. The differential effects were attributed to reduced GLP-1 receptor expression in diabetic islets. In addition, linagliptin treatment increased the relative GLP-1 vs glucagon production in both non-diabetic and diabetic islets, suggesting a positive role of linagliptin in modulating α cell function to restore normoglycemia. Our study indicated that, from the standpoint of islet cell function, linagliptin would be more effective in treating early-stage diabetic patients before they develop severe β cell dysfunction.

Modular Access to N-Substituted cis 5-Amino-3-hydroxypiperidines

A sequence of oxidative cleavage/reductive amination/reductive cleavage enables the preparation of N-substituted cis 5-amino-3-hydroxypiperidines from a readily available bicyclic adduct. This new route provides straightforward and versatile access to drug-relevant scaffolds or fragments.

Pharmacokinetic and pharmacodynamic evaluation of linagliptin for the treatment of type 2 diabetes mellitus, with consideration of Asian patient populations

Our aims were to summarize the clinical pharmacokinetics and pharmacodynamics of the dipeptidyl‐peptidase‐4 inhibitor, linagliptin, and to consider how these characteristics influence its clinical utility. Differences between linagliptin and other dipeptidyl‐peptidase‐4 inhibitors were also considered, in addition to the influence of Asian race on the pharmacology of linagliptin. Linagliptin has a xanthine‐based structure, a difference that might account for some of the pharmacological differences observed with linagliptin versus other dipeptidyl‐peptidase‐4 inhibitors. The long terminal half‐life of linagliptin results from its strong binding to dipeptidyl‐peptidase‐4. Despite this, linagliptin shows a short accumulation half‐life, as a result of saturable, high‐affinity binding to dipeptidyl‐peptidase‐4. The pharmacokinetic characteristics of linagliptin make it suitable for once‐daily dosing in a broad range of patients with type 2 diabetes mellitus. Unlike most other dipeptidyl‐peptidase‐4 inhibitors, linagliptin has a largely non‐renal excretion route, and dose adjustment is not required in patients with renal impairment. Furthermore, linagliptin exposure is not substantially altered in patients with hepatic impairment, and dose adjustment is not necessary for these patients. The 5‐mg dose is also suitable for patients of Asian ethnicity. Linagliptin shows unique pharmacological features within the dipeptidyl‐peptidase‐4 inhibitor class. Although most clinical trials of linagliptin have involved largely Caucasian populations, data on the pharmacokinetic/pharmacodynamic properties of linagliptin show that these features are not substantially altered in Asian populations. The 5‐mg dose of linagliptin is suitable for patients with type 2 diabetes mellitus irrespective of their ethnicity or the presence of renal or hepatic impairment.

Clinical pharmacology of dipeptidyl peptidase 4 inhibitors indicated for the treatment of type 2 diabetes mellitus

Dipeptidyl peptidase-4 (DPP-4) inhibitors are a class of oral antidiabetic drugs that improve glycaemic control without causing weight gain or increasing hypoglycaemic risk in patients with type 2 diabetes mellitus (T2DM). The eight available DPP-4 inhibitors, including alogliptin, anagliptin, gemigliptin, linagliptin, saxagliptin, sitagliptin, teneligliptin, and vildagliptin, are small molecules used orally with identical mechanism of action and similar safety profiles in patients with T2DM. DPP-4 inhibitors may be used as monotherapy or in double or triple combination with other oral glucose-lowering agents such as metformin, thiazolidinediones, or sulfonylureas. Although DPP-4 inhibitors have the same mode of action, they differ by some important pharmacokinetic and pharmacodynamic properties that may be clinically relevant in some patients. The main differences between the eight gliptins include: potency, target selectivity, oral bioavailability, elimination half-life, binding to plasma proteins, metabolic pathways, formation of active metabolite(s), main excretion routes, dosage adjustment for renal and liver insufficiency, and potential drug-drug interactions. The off-target inhibition of selective DPP-4 inhibitors is responsible for multiorgan toxicities such as immune dysfunction, impaired healing, and skin reactions. As a drug class, the DPP-4 inhibitors have become accepted in clinical practice due to their excellent tolerability profile, with a low risk of hypoglycaemia, a neutral effect on body weight, and once-daily dosing. It is unknown if DPP-4 inhibitors can prevent disease progression. More clinical studies are needed to validate the optimal regimens of DPP-4 inhibitors for the management of T2DM when their potential toxicities are closely monitored.

Empagliflozin/Linagliptin: Combination therapy in patients with type 2 diabetes

Glyxambi^® (empagliflozin/linagliptin) is a fixed-dose, once-daily tablet combining a sodium glucose co-transporter-2 (SGLT2) inhibitor with a dipeptidyl peptidase-4 (DPP-4) inhibitor. Glyxambi^® is served as an adjuvant to diet and exercise to improve glycemic control in adults with type 2 diabetes when both empagliflozin and linagliptin are appropriate treatments. Glyxambi^® combines 10mg or 25mg empagliflozin with 5mg linagliptin, with different, complementary mechanisms of action to improve glycemic control in patients with type 2 diabetes. Empagliflozin removes glucose through the urine by blocking blood glucose re-absorption in the kidney, and linagliptin exerts glucose-lowering activity by increasing hormones that stimulate the pancreas to produce more insulin and decreasing the levels of glucagon in the circulation. In addition, this combination therapy modestly reduces body weight and blood pressure without significant safety issues.

Incretin therapies: highlighting common features and differences in the modes of action of glucagon-like peptide-1 receptor agonists and dipeptidyl peptidase-4 inhibitors

Over the last few years, incretin-based therapies have emerged as important agents in the treatment of type 2 diabetes (T2D). These agents exert their effect via the incretin system, specifically targeting the receptor for the incretin hormone glucagon-like peptide 1 (GLP-1), which is partly responsible for augmenting glucose-dependent insulin secretion in response to nutrient intake (the 'incretin effect'). In patients with T2D, pharmacological doses/concentrations of GLP-1 can compensate for the inability of diabetic β cells to respond to the main incretin hormone glucose-dependent insulinotropic polypeptide, and this is therefore a suitable parent compound for incretin-based glucose-lowering medications. Two classes of incretin-based therapies are available: GLP-1 receptor agonists (GLP-1RAs) and dipeptidyl peptidase-4 (DPP-4) inhibitors. GLP-1RAs promote GLP-1 receptor (GLP-1R) signalling by providing GLP-1R stimulation through 'incretin mimetics' circulating at pharmacological concentrations, whereas DPP-4 inhibitors prevent the degradation of endogenously released GLP-1. Both agents produce reductions in plasma glucose and, as a result of their glucose-dependent mode of action, this is associated with low rates of hypoglycaemia; however, there are distinct modes of action resulting in differing efficacy and tolerability profiles. Furthermore, as their actions are not restricted to stimulating insulin secretion, these agents have also been associated with additional non-glycaemic benefits such as weight loss, improvements in β-cell function and cardiovascular risk markers. These attributes have made incretin therapies attractive treatments for the management of T2D and have presented physicians with an opportunity to tailor treatment plans. This review endeavours to outline the commonalities and differences among incretin-based therapies and to provide guidance regarding agents most suitable for treating T2D in individual patients.

Management of patients with type 2 diabetes and mild/moderate renal impairment: profile of linagliptin

Dipeptidyl-peptidase-IV (DPP-4) inhibitors are oral antidiabetic agents that can be administered as monotherapy in patients with contraindications to metformin or metformin intolerance, and in combination with other oral compounds and/or insulin. DPP-4 inhibitors act in a glucose-dependent manner and only increase insulin secretion and inhibit glucagon secretion under hyperglycemic conditions. Renal impairment is frequent in type 2 diabetes as a result of microvascular complications and diabetes treatment, and options in these patients are limited. Linagliptin is a DPP-4 inhibitor with a hepatobiliary route of elimination. In comparative studies, it was noninferior to metformin and sulfonylureas in lowering glycated hemoglobin (HbA_1c) and improving glycemic parameters. It can be used throughout all stages of renal impairment without dose adjustments. This review gives an overview of linagliptin in various stages of chronic kidney disease and has a focus on efficacy and safety parameters from clinical studies in patients with impaired renal function. These data are interpreted in the context of type 2 diabetes therapy in general.

Combination of linagliptin and metformin for the treatment of patients with type 2 diabetes

Type 2 diabetes mellitus (T2DM) is a progressive condition requiring long-term treatment. Most patients with T2DM are unable to maintain normoglycemia using metformin alone; thus, combination therapy is a pivotal part of disease management. Addition of the dipeptidyl peptidase-4 inhibitor linagliptin, with its proven efficacy, low propensity for hypoglycemia, and weight neutrality, has been shown to improve glycemic control for patients who are not well controlled with metformin. As patients often have other comorbidities requiring pharmacotherapy, an increase in pill number, different prescribing frequencies, and timing of medications may adversely impact patients’ adherence. Studies have shown that treatment nonadherence contributes to increased morbidity, mortality, and healthcare cost. In the United States, the single-pill combination (SPC) of linagliptin/metformin is available in three strengths approved for twice-daily administration: 2.5/500 mg, 2.5/850 mg, and 2.5/1000 mg. The SPC has the potential to reduce pill burden and simplify patients’ treatment regimens, thereby promoting improved adherence and efficacy.

The pharmacokinetic considerations and adverse effects of DPP-4 inhibitors [corrected]

INTRODUCTION

Dipeptidyl-peptidase-4 (DPP-4) inhibitors are a class of anti-hyperglycemic agents with proven efficacy in patients with type 2 diabetes mellitus (T2DM).

AREAS COVERED

This review considers the pharmacokinetic profile, adverse effects and drug interactions of DPP-4 inhibitors. DPP-4 inhibitors have certain differences in their structure, metabolism, route of elimination and selectivity for DPP-4 over structurally related enzymes, such as DPP-8/DPP-9. They have a low potential for drug interactions, with the exception of saxagliptin that is largely metabolized by cytochrome CYP3A4/A5. Reports of pancreatitis and pancreatic cancer have raised concerns regarding the safety of DPP-4 inhibitors and are under investigation. Post-marketing surveillance has revealed less common adverse effects, especially a number of skin- and immune-related adverse effects. These issues are covered in the present review.

EXPERT OPINION

DPP-4 inhibitors are useful and efficient drugs. DPP-4 inhibitors have similar mechanism of action and similar efficacy. However, DPP-4 inhibitors have certain differences in their pharmacokinetic properties that may be associated with different clinical effects and adverse event profiles. Although clinical trials indicated a favorable safety profile, post-marketing reports revealed certain safety aspects that need further investigation. Certainly, more research is needed to clarify if the differences among DPP-4 inhibitors could lead to a different clinical and safety profile.

Probable linagliptin-induced liver toxicity: a case report

AIM

Unlike other dipeptidyl peptidase 4 (DPP-4) inhibitors, the excretion of linagliptin is mainly through a biliary route. Despite this fact, liver injury with linagliptin has thus far not been reported in the literature. However, this report describes the first case of probable linagliptin-induced liver toxicity.

METHODS

The clinical history, diagnosis, investigations and drug treatment of the patient are reviewed here.

RESULTS

A 58-year-old Japanese woman presented with fatigue, nausea, jaundice and marked elevations of hepatic enzymes 4weeks after starting linagliptin 5mg/day as monotherapy. No other medications were taken, and imaging studies revealed no other obvious causes of hepatic injury. Tests for viral serology and antinuclear antigen were negative. Symptoms disappeared and the levels of hepatic parameters (serum aminotransferases and biliary enzymes) slowly recovered after discontinuation of linagliptin. The slow recovery process may have been due to the very long half-life of the drug. The patient's Naranjo scale score was 6 and RUCAM score was 7.

CONCLUSION

Although linagliptin currently carries no liver warnings, it may be necessary to monitor hepatic function in some patients upon administration of this drug until further evidence is obtained.

Clinical utility of the dipeptidyl peptidase-4 inhibitor linagliptin

INTRODUCTION

Dipeptidyl peptidase-4 (DPP-4) inhibitors have emerged as new options in the management of type 2 diabetes mellitus, demonstrating meaningful antihyperglycemic effects and good tolerability profiles. Glycemic control is improved by preventing the DPP-4-mediated degradation of incretin hormones, with a resulting increase in insulin secretion and inhibition of glucagon secretion.

PURPOSE

This article provides a discussion of the clinical utility of linagliptin.

RESULTS AND CONCLUSION

Linagliptin is a xanthine-based, oral DPP-4 inhibitor that has been approved in the United States and Europe. It has been evaluated extensively in clinical trials, and results in improved glycemic control when used as monotherapy, initial combination therapy with metformin or pioglitazone, add-on therapy to metformin and/or a sulfonylurea, or add-on therapy to basal insulin (with or without oral antidiabetic drugs). Consistent with other members of its class, the benefits of linagliptin also include a low risk of hypoglycemia and weight gain. However, linagliptin is the first DPP-4 inhibitor to be approved as a once-daily, 5-mg dose and, due to its primarily non-renal route of excretion, no dosage adjustment is required for patients with renal or hepatic impairment. The pharmacokinetics and pharmacodynamics of linagliptin are not affected to a clinically meaningful degree by race or ethnicity and linagliptin has very low potential for drug-drug interactions.

Linagliptin: farmacology, efficacy and safety in type 2 diabetes treatment

Type 2 diabetes mellitus (T2DM) has a high prevalence and incidence around the world. The complex pathophysiology mechanism is among the barriers for diabetes treatment. Type 2 diabetes patients have dysfunction in incretin hormones (as glucagon-like peptide-1 or GLP-1, and glucose-dependent insulinotropic polypeptide or GIP). By inhibiting the dipeptidyl peptidase-4 (DPP-4) enzyme, it is possible to slow the inactivation of GLP-1 and GIP, promoting blood glucose level reduction in a glucose-dependent manner. Linagliptin is a highly specific and potent inhibitor of DPP-4 that is currently indicated for the treatment of type 2 diabetes. Clinical studies with linagliptin demonstrated efficacy in reducing glycated hemoglobin (HbA1c) levels in type 2 diabetes patients, while maintaining a placebo-like safety and tolerability profile. Linagliptin has an interesting pharmacokinetic profile in terms of its predominantly non-renal elimination and the main implication of this characteristic is that no dose adjustment is necessary in patients with renal disease. Also, no dose adjustment is required in patients with hepatic insufficiency, as well in elderly or obese patients. This article will review the pharmacokinetic profile, efficacy data and safety aspects of linagliptin in type 2 diabetes patients.

Clinical overview of linagliptin, a dipeptidyl peptidase-4 inhibitor, in patients with Type 2 diabetes mellitus

Linagliptin is a pharmacologically unique, orally active, once-daily dipeptidyl peptidase-4 inhibitor indicated for the treatment of hyperglycemia in patients with Type 2 diabetes mellitus. Compared with other dipeptidyl peptidase-4 inhibitors, linagliptin has a favorable pharmacokinetic profile with a primarily nonrenal route of elimination that avoids the need for dose adjustment in patients with renal impairment. When administered as monotherapy or in combination with other antihyperglycemic drugs, linagliptin treatment leads to clinically meaningful reductions in glycated hemoglobin, fasting plasma glucose and postprandial plasma glucose levels. In addition, pancreatic β-cell function is enhanced. Linagliptin treatment is well tolerated, with weight-neutral effects and no increased risk of hypoglycemia. Of note, linagliptin treatment was associated with a significantly reduced risk of cardiovascular events in clinical trials of ≤2 years, although this finding remains to be confirmed in larger and longer clinical outcomes studies.

Linagliptin/Metformin fixed-dose combination treatment: a dual attack to type 2 diabetes pathophysiology

Combination therapies are a widely accepted approach to type 2 diabetes treatment, considering that monotherapies fail to provide adequate glycemic control in the majority of cases. The combination of oral antidiabetic agents into a single tablet would significantly simplify the therapeutic regimen and maximize patients' adherence to treatment. Recently, a fixed-dose, single-tablet, combined formulation of linagliptin (a dipeptidyl peptidase-4 inhibitor) and metformin has been approved for use in type 2 diabetic patients, and is indicated as an adjunct to diet and exercise for those patients who remain inadequately controlled despite maximal tolerated doses of metformin, metformin and sulfonylurea, or linagliptin and metformin monotherapies. The combination tablet is administered twice daily and can be used either alone or combined with sulfonylureas. Clinical trials suggest that this fixed-dose combination provides significantly superior glycemic control compared to linagliptin and metformin monotherapy, in terms of improving key parameters of glucose homeostasis such as glycosylated hemoglobin, fasting and postprandial glucose levels. It also exhibits an excellent tolerability profile, without promoting weight gain and hypoglycemic episodes. The compounds of this formulation do not display clinically relevant pharmacokinetic interactions with each other, and exert synergistic (complementary) pharmacodynamic effects, including an enhanced incretin effect, suppressed hepatic glucose production, and improved peripheral insulin sensitivity. As a result, a linagliptin/metformin fixed-dose combination offers the potential to address multiple defects of type 2 diabetes pathophysiology (pancreatic islet dysfunction, insulin resistance, increased hepatic glucose output), and most importantly, in the context of a safe, efficacious, flexible, and convenient therapeutic regimen.

Potential role of linagliptin as an oral once-daily treatment for patients with type 2 diabetes

BACKGROUND

Linagliptin is an oral antihyperglycemic agent that selectively inhibits the enzyme dipeptidyl peptidase-4 (DPP-4). Inhibition of DPP-4 increases the levels of the incretin hormones glucagon-like peptide and glucose-dependent insulinotropic polypeptide by preventing their degradation.

OBJECTIVE

We reviewed the role of linagliptin as an oral once-daily treatment for patients with type 2 diabetes.

METHODS

A comprehensive literature search was performed using the term "linagliptin." Original research articles and review articles were included in our examination.

RESULTS

Linagliptin has a similar mode of action as other gliptins, with comparable efficacy, safety profile, and tolerability. Differences in pharmacokinetic parameters that distinguish linagliptin from other gliptins include that linagliptin is not renally excreted and does not require dose reduction with renal impairment.

CONCLUSION

Linagliptin is an oral, once-daily, antihyperglycemic agent that significantly reduces glycated hemoglobin (HbA(1c)) when used alone or in combination with other antidiabetic drugs in people with type 2 diabetes. Pharmacokinetics, such as the lack of renal excretion, distinguishes linagliptin from other gliptins.