Clinical pharmacokinetics and pharmacodynamics of vildagliptin

Update on the treatment of type 2 diabetes mellitus

To achieve good metabolic control in diabetes and keep long term, a combination of changes in lifestyle and pharmacological treatment is necessary. Achieving near-normal glycated hemoglobin significantly, decreases risk of macrovascular and microvascular complications. At present there are different treatments, both oral and injectable, available for the treatment of type 2 diabetes mellitus (T2DM). Treatment algorithms designed to reduce the development or progression of the complications of diabetes emphasizes the need for good glycaemic control. The aim of this review is to perform an update on the benefits and limitations of different drugs, both current and future, for the treatment of T2DM. Initial intervention should focus on lifestyle changes. Moreover, changes in lifestyle have proven to be beneficial, but for many patients is a complication keep long term. Physicians should be familiar with the different types of existing drugs for the treatment of diabetes and select the most effective, safe and better tolerated by patients. Metformin remains the first choice of treatment for most patients. Other alternative or second-line treatment options should be individualized depending on the characteristics of each patient. This article reviews the treatments available for patients with T2DM, with an emphasis on agents introduced within the last decade.

Efficacy of different dipeptidyl peptidase-4 (DPP-4) inhibitors on metabolic parameters in patients with type 2 diabetes undergoing dialysis

Hyperglycemia is associated with increased mortality and morbidity in patients with type 2 diabetes mellitus (T2DM) who are undergoing dialysis. Although dipeptidyl peptidase-4 (DPP-4) inhibitors have been widely used in end-stage renal disease (ESRD) patients with T2DM, there are few studies on their efficacy in this population. We studied the effect of 3 different DPP-4 inhibitors on metabolic parameters in ESRD patients with T2DM.Two hundred ESRD patients with T2DM who were treated with DPP-4 inhibitors (sitagliptin, vildagliptin, or linagliptin) were enrolled and analyzed retrospectively. The changes in glycated hemoglobin (HbA1c), fasting plasma glucose, and lipid profiles were assessed before and after 3 months of treatment with DPP-4 inhibitors. Subgroup analysis was done for each hemodialysis (HD) and peritoneal dialysis (PD) group.There was no significant difference in the decrease in the HbA1c level among sitagliptin, vildagliptin, and linagliptin treatment groups (-0.74 ± 1.57, -0.39 ± 1.45, and -0.08 ± 1.40, respectively, P = 0.076). The changes in fasting blood glucose and lipid profiles were also not significantly different. In HD patients (n = 115), there was no difference in the HbA1c level among the 3 groups. In contrast, in PD patients (n = 85), HbA1c was reduced more after 3 months of treatment with sitagliptin compared with vildagliptin and linagliptin (-1.58 ± 0.95, -0.46 ± 0.98, -0.04 ± 1.22, respectively, P = 0.001).There was no significant difference in the glucose-lowering effect between the different DPP-4 inhibitors tested in ESRD patients. In PD patients, sitagliptin tends to lower the HbA1c level more than the other inhibitors. The glucose-lowering efficacy of the 3 DPP-4 inhibitors was comparable.

Pharmacological Actions of Glucagon-Like Peptide-1, Gastric Inhibitory Polypeptide, and Glucagon

Glucagon family of peptide hormones is a group of structurally related brain-gut peptides that exert their pleiotropic actions through interactions with unique members of class B1 G protein-coupled receptors (GPCRs). They are key regulators of hormonal homeostasis and are important drug targets for metabolic disorders such as type-2 diabetes mellitus (T2DM), obesity, and dysregulations of the nervous systems such as migraine, anxiety, depression, neurodegeneration, psychiatric disorders, and cardiovascular diseases. The current review aims to provide a detailed overview of the current understanding of the pharmacological actions and therapeutic advances of three members within this family including glucagon-like peptide-1 (GLP-1), gastric inhibitory polypeptide (GIP), and glucagon.

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.

Application of pharmacometric approaches to evaluate effect of weight and renal function on pharmacokinetics of alogliptin

AIMS

The aims of the study were to characterize the pharmacokinetics (PK) of alogliptin in healthy and type 2 diabetes mellitus (T2DM) subjects using a population PK approach and to assess the influence of various covariates on alogliptin exposure.

METHODS

Plasma concentration data collected from two phase 1 studies and one phase 3 study following administration of alogliptin (12.5-400 mg) were used for the PK model development. One- and two-compartment models were evaluated as base structural PK models. The impact of selected covariates was assessed using stepwise forward selection and backward elimination procedures. The predictability and robustness of the final model was evaluated using visual predictive check and bootstrap analyses. The final model was used to perform simulations and guide appropriate dose adjustments.

RESULTS

A two-compartment model with first-order absorption and elimination best described the alogliptin concentration vs. time profiles. Creatinine clearance and weight had a statistically significant effect on the oral clearance (CL/F) of alogliptin. The model predicted a lower CL/F (17%, 35%, 80%) and a higher systemic exposure (56%, 89%, 339%) for subjects with mild, moderate and severe renal impairment, respectively, compared with healthy subjects. Effect of weight on CL/F was not considered clinically relevant. Simulations at different doses of alogliptin support the approved doses of 12.5 mg and 6.25 mg for patients with moderate and severe renal impairment, respectively.

CONCLUSIONS

The PK of alogliptin was well characterized by the model. The analysis suggested an alogliptin dose adjustment for subjects with moderate-to-severe renal impairment and no dose adjustments based on weight.

Pharmacokinetics and clinical use of incretin-based therapies in patients with chronic kidney disease and type 2 diabetes

The prevalence of chronic kidney disease (CKD) of stages 3-5 (glomerular filtration rate [GFR] <60 mL/min) is about 25-30 % in patients with type 2 diabetes mellitus (T2DM). While most oral antidiabetic agents have limitations in patients with CKD, incretin-based therapies are increasingly used for the management of T2DM. This review analyses (1) the influence of CKD on the pharmacokinetics of dipeptidyl peptidase-4 (DPP-4) inhibitors and glucagon-like peptide-1 (GLP-1) receptor agonists; and (2) the efficacy/safety profile of these agents in clinical practice when prescribed in patients with both T2DM and CKD. Most DPP-4 inhibitors (sitagliptin, vildagliptin, saxagliptin, alogliptin) are predominantly excreted by the kidneys. Thereby, pharmacokinetic studies showed that total exposure to the drug is increased in proportion to the decline of GFR, leading to recommendations for appropriate dose reductions according to the severity of CKD. In these conditions, clinical studies reported a good efficacy and safety profile in patients with CKD. In contrast, linagliptin is eliminated by a predominantly hepatobiliary route. As a pharmacokinetic study showed only minimal influence of decreased GFR on total exposure, no dose adjustment of linagliptin is required in the case of CKD. The experience with GLP-1 receptor agonists in patients with CKD is more limited. Exenatide is eliminated by renal mechanisms and should not be given in patients with severe CKD. Liraglutide is not eliminated by the kidney, but it should be used with caution because of the limited experience in patients with CKD. Only limited pharmacokinetic data are also available for lixisenatide, exenatide long-acting release (LAR) and other once-weekly GLP-1 receptor agonists in current development. Several case reports of acute renal failure have been described with GLP-1 receptor agonists, probably triggered by dehydration resulting from gastrointestinal adverse events. However, increasing GLP-1 may also exert favourable renal effects that could contribute to reducing the risk of diabetic nephropathy. In conclusion, the already large reassuring experience with DPP-4 inhibitors in patients with CKD offers new opportunities to the clinician, whereas more caution is required with GLP-1 receptor agonists because of the limited experience in this population.

Diabetes therapies in hemodialysis patients: Dipeptidase-4 inhibitors

Although several previous studies have been published on the effects of dipeptidase-4 (DPP-4) inhibitors in diabetic hemodialysis (HD) patients, the findings have yet to be reviewed comprehensively. Eyesight failure caused by diabetic retinopathy and aging-related dementia make multiple daily insulin injections difficult for HD patients. Therefore, we reviewed the effects of DPP-4 inhibitors with a focus on oral antidiabetic drugs as a new treatment strategy in HD patients with diabetes. The following 7 DPP-4 inhibitors are available worldwide: sitagliptin, vildagliptin, alogliptin, linagliptin, teneligliptin, anagliptin, and saxagliptin. All of these are administered once daily with dose adjustments in HD patients. Four types of oral antidiabetic drugs can be administered for combination oral therapy with DPP-4 inhibitors, including sulfonylureas, meglitinide, thiazolidinediones, and alpha-glucosidase inhibitor. Nine studies examined the antidiabetic effects in HD patients. Treatments decreased hemoglobin A1c and glycated albumin levels by 0.3% to 1.3% and 1.7% to 4.9%, respectively. The efficacy of DPP-4 inhibitor treatment is high among HD patients, and no patients exhibited significant severe adverse effects such as hypoglycemia and liver dysfunction. DPP-4 inhibitors are key drugs in new treatment strategies for HD patients with diabetes and with limited choices for diabetes treatment.

Pharmacokinetics in patients with chronic liver disease and hepatic safety of incretin-based therapies for the management of type 2 diabetes mellitus

Patients with type 2 diabetes mellitus have an increased risk of chronic liver disease (CLD) such as non-alcoholic fatty liver disease and steatohepatitis, and about one-third of cirrhotic patients have diabetes. However, the use of several antidiabetic agents, such as metformin and sulphonylureas, may be a concern in case of hepatic impairment (HI). New glucose-lowering agents targeting the incretin system are increasingly used for the management of type 2 diabetes. Incretin-based therapies comprise oral inhibitors of dipeptidyl peptidase-4 (DPP-4) (gliptins) or injectable glucagon-like peptide-1 (GLP-1) receptor agonists. This narrative review summarises the available data regarding the use of both incretin-based therapies in patients with HI. In contrast to old glucose-lowering agents, they were evaluated in specifically designed acute pharmacokinetic studies in patients with various degrees of HI and their hepatic safety was carefully analysed in large clinical trials. Only mild changes in pharmacokinetic characteristics of DPP-4 inhibitors were observed in patients with different degrees of HI, presumably without major clinical relevance. GLP-1 receptor agonists have a renal excretion rather than liver metabolism. Specific pharmacokinetic data in patients with HI are only available for liraglutide. No significant changes in liver enzymes were reported with DPP-4 inhibitors or GLP-1 receptor agonists, alone or in combination with various other glucose-lowering agents, in clinical trials up to 2 years in length. On the contrary, preliminary data suggested that incretin-based therapies may be beneficial in patients with CLD, more particularly in the presence of non-alcoholic fatty liver disease. Nevertheless, caution should be recommended, especially in patients with advanced cirrhosis, because of a lack of clinical experience with incretin-based therapies in these vulnerable patients.

Racial/ethnic disparities in prevalence and care of patients with type 2 diabetes mellitus

BACKGROUND

As of 2012, nearly 10% of Americans had diabetes mellitus. People with diabetes are at approximately double the risk of premature death compared with those in the same age groups without the condition. While the prevalence of diabetes has risen across all racial/ethnic groups over the past 30 years, rates are higher in minority populations. The objective of this review article is to evaluate the prevalence of diabetes and disease-related comorbidities as well as the primary endpoints of clinical studies assessing glucose-lowering treatments in African Americans, Hispanics, and Asians.

METHODS

As part of our examination of this topic, we reviewed epidemiologic and outcome publications. Additionally, we performed a comprehensive literature search of clinical trials that evaluated glucose-lowering drugs in racial minority populations. For race/ethnicity, we used the terms African American, African, Hispanic, and Asian. We searched PubMed for clinical trial results from 1996 to 2015 using these terms by drug class and specific drug. Search results were filtered qualitatively.

RESULTS

Overall, the majority of publications that fit our search criteria pertained to native Asian patient populations (i.e., Asian patients in Asian countries). Sulfonylureas; the α-glucosidase inhibitor, miglitol; the biguanide, metformin; and the thiazolidinedione, rosiglitazone have been evaluated in African American and Hispanic populations, as well as in Asians. The literature on other glucose-lowering drugs in non-white races/ethnicities is more limited.

CONCLUSIONS

Clinical data are needed for guiding diabetes treatment among racial minority populations. A multi-faceted approach, including vigilant screening in at-risk populations, aggressive treatment, and culturally sensitive patient education, could help reduce the burden of diabetes on minority populations. To ensure optimal outcomes, educational programs that integrate culturally relevant approaches should highlight the importance of risk-factor control in minority patients.

Dipeptidyl peptidase-4 greatly contributes to the hydrolysis of vildagliptin in human liver

The major metabolic pathway of vildagliptin in mice, rats, dogs, and humans is hydrolysis at the cyano group to produce a carboxylic acid metabolite M20.7 (LAY151), whereas the major metabolic enzyme of vildagliptin has not been identified. In the present study, we determined the contribution rate of dipeptidyl peptidase-4 (DPP-4) to the hydrolysis of vildagliptin in the liver. We performed hydrolysis assay of the cyano group of vildagliptin using mouse, rat, and human liver samples. Additionally, DPP-4 activities in each liver sample were assessed by DPP-4 activity assay using the synthetic substrate H-glycyl-prolyl-7-amino-4-methylcoumarin (Gly-Pro-AMC). M20.7 formation rates in liver microsomes were higher than those in liver cytosol. M20.7 formation rate was significantly positively correlated with the DPP-4 activity using Gly-Pro-AMC in liver samples (r = 0.917, P < 0.01). The formation of M20.7 in mouse, rat, and human liver S9 fraction was inhibited by sitagliptin, a selective DPP-4 inhibitor. These findings indicate that DPP-4 is greatly involved in vildagliptin hydrolysis in the liver. Additionally, we established stable single expression systems of human DPP-4 and its R623Q mutant, which is the nonsynonymous single-nucleotide polymorphism of human DPP-4, in human embryonic kidney 293 (HEK293) cells to investigate the effect of R623Q mutant on vildagliptin-hydrolyzing activity. M20.7 formation rate in HEK293 cells expressing human DPP-4 was significantly higher than that in control HEK293 cells. Interestingly, R623Q mutation resulted in a decrease of the vildagliptin-hydrolyzing activity. Our findings might be useful for the prediction of interindividual variability in vildagliptin pharmacokinetics.

Vildagliptin added to sulfonylurea improves glycemic control without hypoglycemia and weight gain in Chinese patients with type 2 diabetes mellitus

OBJECTIVE

The aim of the present study was to assess the efficacy and safety of vildagliptin as add-on to sulfonylurea therapy in Chinese patients with type 2 diabetes mellitus (T2DM) inadequately controlled on sulfonylurea monotherapy.

METHODS

The 24-week randomized double-blind placebo-controlled study compared vildagliptin 50 mg, q.d., with placebo as add-on to glimepiride in T2DM patients who were inadequately controlled (HbA1c 7.5%-11.0% [58-97 mmol/mol]) on a stable dose of sulfonylurea for ≥12 weeks before study entry.

RESULTS

In all, 279 patients were randomized to receive either vildagliptin (n = 143) or placebo (n = 136). At baseline, overall mean age was 58.5 years, body weight 68.1 kg, duration of diabetes 6.9 years and daily glimepiride dose 3.3 mg. After 24 weeks, the adjusted mean change (AMΔ) in HbA1c was -0.7% (-8 mmol/mol; baseline 8.6%, 70 mmol/mol) in the vildagliptin group and -0.2% (-2 mmol/mol; baseline 8.7%, 72 mmol/mol) in the placebo group, with a treatment difference of -0.5% (-5 mmol/mol; P < 0.001). The between-group difference in AMΔ in fasting plasma glucose was -0.4 mmol/L (P = 0.160). There was a slight, but not significant, decrease in body weight in both groups. No hypoglycemic events were reported in either group, including those patients reaching HbA1c <7.0%. Patients in the vildagliptin and placebo groups reported low and comparable incidences of adverse events (14.0% vs. 17.8%) and serious adverse events (0.7% in each group).

CONCLUSION

Vildagliptin 50 mg, q.d., added to sulfonylurea monotherapy is effective in Chinese patients with T2DM, without increasing the risk of hypoglycemia and weight gain.

Pharmacokinetic and pharmacodynamic interaction between gemigliptin and metformin in healthy subjects

BACKGROUND AND OBJECTIVE

Gemigliptin is a novel dipeptidyl peptidase-4 (DPP-4) inhibitor used in the treatment of type 2 diabetes mellitus. This study evaluated possible pharmacodynamic and pharmacokinetic interactions between gemigliptin and metformin and investigated their tolerability.

METHODS

A randomized, open-label, multiple-dose, three-treatment, three-period, three-sequence crossover study was conducted in healthy male subjects. Twenty-seven subjects received gemigliptin (50 mg once daily), metformin (1,000 mg twice a day), or both drugs for 7 days per dosing period. Blood samples were drawn over 24 h on the seventh day of each period for pharmacokinetic and pharmacodynamic evaluations, including plasma DPP-4 activity and total/active glucagon-like peptide-1 (GLP-1) levels. Meal tolerance tests were conducted for pharmacodynamic assessment on the eighth day. Safety and tolerability were evaluated using adverse events, vital signs, ECGs, and clinical laboratory tests.

RESULTS

Coadministration of gemigliptin and metformin had no significant effect on the pharmacokinetics of gemigliptin or metformin. The inhibition of DPP-4 by gemigliptin was not affected by coadministration with metformin. Co-therapy of gemigliptin and metformin showed additional effects by increasing plasma active GLP-1 concentrations and lowering serum glucose levels. The plasma glucagon level was lower in co-therapy than with metformin monotherapy. The coadministration of gemigliptin and metformin was well-tolerated without serious adverse events.

CONCLUSIONS

Coadministration of gemigliptin and metformin showed beneficial anti-diabetic effects without pharmacokinetic drug-drug interactions.

DPP-4 inhibitors: focus on safety

INTRODUCTION

Dipeptidyl peptidase inhibitors (DPP-4-i) are highly selective inhibitors of the enzyme DPP-4. They act by increasing levels of incretin hormones, which have potent effects on insulin and glucagon release, gastric emptying, and satiety. Our goal is to review the safety issues related to DPP-4-i.

AREAS COVERED

This review is based upon a PubMed search of the literature using keywords alogliptin, linagliptin, saxagliptin, sitagliptin and vildagliptin, DPP-4-i, glucagon-like polypeptide-1 agonists, as well as extensive personal clinical trial experience with each of these agents. The current DPP-4-i have very different chemical structures. Saxagliptin has significant cytochrome P450 metabolism and carries a risk of drug interactions. Linagliptin has primarily entero-hepatic excretion, a benefit in renally impaired patients. A concern arose related to congestive heart failure in the SAVOR TIMI trial of saxagliptin. Several major cardiac studies are underway, with two concluded. Despite lingering uncertainty related to pancreatitis and pancreatic cancer, large randomized trials have not shown an increased risk with DPP-4-i treatment. Cutaneous adverse effects occur with a low frequency with some of these agents.

EXPERT OPINION

DPP-4-i are an additional choice in the group of anti-hyperglycemics. Their principal advantage is a low incidence of hypoglycemia, making these agents desirable in patients such as the elderly and those with cardiac disease. Several large trials have hinted at less cardiac risk with DPP-4-i than with sulfonylureas. The CAROLINA Trial comparing linagliptin and glimepiride may provide a conclusive answer to this question.

Effectiveness and Tolerability of Second-Line Therapy with Vildagliptin Versus Other Oral Agents in Type 2 Diabetes (EDGE): Post Hoc Sub-Analysis of Bulgarian Data

OBJECTIVES

Metformin is an established first-line treatment for type 2 diabetes mellitus (T2DM) patients but intensification of oral anti-diabetic therapy is usually required over time. The effectiveness of diabetes control with vildaGliptin and vildagliptin/mEtformin (EDGE) study compared effectiveness and safety of vildagliptin and other oral anti-diabetic drugs (OAD) in 45,868 patients worldwide with inadequately controlled T2DM by monotherapy under real-life conditions. Here, we present effectiveness results for patients receiving vildagliptin (vildagliptin cohort) or another OAD (comparator cohort) add-on to monotherapy in Bulgaria.

METHODS

The eligible diabetes patients inadequately controlled with current monotherapy were assigned to add-on treatment, which was chosen by the physician based on patient's need. Effectiveness was assessed by glycated hemoglobin (HbA1c) drop and by means of a composite endpoint assessing the proportion of patients responding to treatment (HbA1c <7%) without proven hypoglycemic event and significant weight gain (>5%) after 12 months of treatment.

RESULTS

In total, 754 patients were enrolled in Bulgaria, 384 in the vildagliptin cohort and 369 in the comparator cohort. Mean HbA1c change from baseline was significantly higher with vildagliptin compared to the comparator (-1.35% in the vildagliptin cohort and -0.55% in the comparator cohort, P < 0.001). In the vildagliptin cohort, a higher proportion of patients reached the composite endpoint (HbA1c <7%, no hypoglycemic events, no weight gain) when compared to the comparator cohort (vildagliptin: 32.3%; comparator: 8.4%; P < 0.001). Overall, vildagliptin was well tolerated with similarly low incidences of total adverse events (3.4% versus 1.9% in the comparator group) and serious adverse events (2.3% versus 1.1% in the comparator group).

CONCLUSIONS

In real-life clinical practice in Bulgaria, vildagliptin is associated with a greater HbA1c drop, and a higher proportion of patients reaching target HbA1c without hypoglycemia and weight gain compared to comparator.

Vildagliptin , a DPP-4 inhibitor for the twice-daily treatment of type 2 diabetes mellitus with or without metformin

INTRODUCTION

Dipeptidyl peptidase-4 inhibitors increase circulating levels of glucagon-like peptide 1 (GLP-1) and glucose dependent insulinotropic polypeptide regulating glucose-dependent insulin secretion. In addition, GLP-1 suppresses glucagon secretion, delays gastric emptying and increases satiety. The combination of vildagliptin with the biguanide metformin is of particular interest because of its complementary mode of action, addressing insulin resistance, alpha- and beta cell function in the islet of the pancreas.

AREAS COVERED

Because of the abundance of data supporting the use of vildagliptin alone and in combination with metformin, the present paper aims at giving an overview on the current evidence for its use in patients with type 2 diabetes mellitus.

EXPERT OPINION

The data suggest that vildagliptin offers similar glycemic control compared to sulfonylureas and thiazolidinediones, while having the benefit of being associated with fewer cases of hypoglycemia and less body weight gain. There is increasing evidence that compared with sulfonylureas, vildagliptin has favorable effects on pancreatic alpha- and beta-cell function. Vildagliptin in combination with metformin, improve glycemic control with a favorable safety and tolerability profile, making it an attractive therapeutic option in patients where metformin monotherapy alone is not sufficient.

Multiple-dose pharmacokinetics and pharmacodynamics of evogliptin (DA-1229), a novel dipeptidyl peptidase IV inhibitor, in healthy volunteers

Purpose

Evogliptin (DA-1229) is a novel, potent, and selective dipeptidyl peptidase IV (DPP-IV) inhibitor in clinical development for the treatment of type 2 diabetes mellitus. This study aimed to investigate the pharmacokinetic and pharmacodynamic profiles and tolerability of evogliptin after repeated oral administration in healthy subjects.

Patients and methods

A block-randomized, double-blind, placebo-controlled, multiple-dose, dose-escalation study was performed in a total of 30 subjects. Repeated once-daily doses of 5, 10, or 20 mg evogliptin or the same doses of placebo were orally administered to ten subjects in each dosage group for 10 days. Subjects in each group were randomized to receive evogliptin or placebo with a ratio of 8:2. Pharmacokinetics of evogliptin were evaluated, with its concentrations in serial plasma and urine samples collected following the first and last administrations. DPP-IV activity and glucagon-like peptide-1, glucose, and insulin levels were quantified to evaluate evogliptin’s pharmacodynamics on the first and last dosing days.

Results

All participants completed the study without any serious or severe adverse event. The evogliptin plasma concentration reached its peak within 4–5 hours and decreased relatively slowly, with a terminal elimination half-life of 33–39 hours. Repeated administration resulted in a 1.4- to 1.5-fold accumulation. Evogliptin’s systemic exposure and inhibition of plasma DPP-IV activity increased in a dose-dependent manner. Inhibition of DPP-IV activity >80% was sustained over 24 hours in all evogliptin dose groups and provided an increase in postprandial active glucagon-like peptide-1 levels by 1.5- to 2.4-fold. Postprandial glucose levels in the evogliptin-treated groups were reduced 20%–35% compared to placebo, but were not accompanied by increased insulin levels.

Conclusion

Repeated administration of evogliptin in healthy subjects was well tolerated and exhibited linear pharmacokinetics within the 5–20 mg dose range. A once-daily regimen of 5–20 mg evogliptin effectively inhibited DPP-IV activity.

Dipeptidyl peptidase-4 inhibitors: pharmacokinetics, efficacy, tolerability and safety in renal impairment

The dipeptidyl peptidase-4 (DPP-4) inhibitors are a new class of blood glucose-lowering therapy with proven efficacy, tolerability and safety. Four of the five commercially available DPP-4 inhibitors are subject to significant renal clearance, and pharmacokinetic studies in people with renal impairment have led to lower recommended doses based on creatinine clearance in order to prevent drug accumulation. Data from these pharmacokinetic studies and from supratherapeutic doses in healthy individuals and people with uncomplicated diabetes during development suggest, however, that there is a wide therapeutic margin. This should protect against toxicity if people with renal impairment are inadvertently prescribed higher doses than recommended. Doses appropriate to renal function are associated with reductions in HbA1c that are equivalent to those observed in people with type 2 diabetes who do not have renal impairment. Recent large-scale cardiovascular safety trials of saxagliptin and alogliptin have identified heart failure as a potential concern and renal impairment may increase the risk of this complication. Although the incidence of pancreatitis does not appear to be significantly increased by DPP-4 inhibitor therapy, renal impairment is also an independent risk factor. Additional data from other ongoing DPP-4 inhibitor cardiovascular safety trials should provide a more precise assessment of the risks of these uncommon complications, including in people with renal impairment.

The Effect of DPP-4 Inhibitors on Metabolic Parameters in Patients with Type 2 Diabetes

BACKGROUND

We evaluated the effects of two dipeptidyl peptidase-4 (DPP-4) inhibitors, sitagliptin and vildagliptin, on metabolic parameters in patients with type 2 diabetes mellitus.

METHODS

A total of 170 type 2 diabetes patients treated with sitagliptin or vildagliptin for more than 24 weeks were selected. The patients were separated into two groups, sitagliptin (100 mg once daily, n=93) and vildagliptin (50 mg twice daily, n=77). We compared the effect of each DPP-4 inhibitor on metabolic parameters, including the fasting plasma glucose (FPG), postprandial glucose (PPG), glycated hemoglobin (HbA1c), and glycated albumin (GA) levels, and lipid parameters at baseline and after 24 weeks of treatment.

RESULTS

The HbA1c, FPG, and GA levels were similar between the two groups at baseline, but the sitagliptin group displayed a higher PPG level (P=0.03). After 24 weeks of treatment, all of the glucose-related parameters were significantly decreased in both groups (P=0.001). The levels of total cholesterol and triglycerides were only reduced in the vildagliptin group (P=0.001), although the sitagliptin group received a larger quantity of statins than the vildagliptin group (P=0.002).The mean change in the glucose- and lipid-related parameters after 24 weeks of treatment were not significantly different between the two groups (P=not significant). Neither sitagliptin nor vildagliptin treatment was associated with a reduction in the high sensitive C-reactive protein level (P=0.714).

CONCLUSION

Vildagliptin and sitagliptin exert a similar effect on metabolic parameters, but vildagliptin exerts a more potent beneficial effect on lipid parameters.

Glucose turnover after replacement of usual therapy by insulin in insulin-naive type 2 diabetes subjects

CONTEXT

Discontinuation of anti-hyperglycemic oral agents and initiation of insulin is recommended in certain clinical situations for inpatients with type 2 diabetes (T2D). The effects on glucose turnover when these agents are acutely withdrawn are poorly understood and may be of importance when insulin therapy is initiated.

OBJECTIVE

Our objective was to investigate alterations in glucose turnover after acute withdrawal of noninsulin therapy.

DESIGN AND SETTING

This was a randomized crossover study at a clinical research facility.

PARTICIPANTS

Participants included 12 insulin-naive subjects with T2D.

METHODS

Subjects attended two 24-hour visits. Standard therapy was discontinued and replaced by closed-loop insulin delivery during the intervention visit. Usual anti-hyperglycemic therapy was continued during the control visit. Systemic glucose appearance (Ra) and glucose disposal (Rd) were measured using a tracer dilution technique with iv [6,6-(2)H2]glucose.

RESULTS

Plasma glucose profiles during both visits were comparable (P = .48). Glucose Ra increased during the day (21.4 [19.5, 23.5] vs 18.6 [17.0, 21.6) μmol/kg/min, P = .019) and decreased overnight (9.7 [8.5, 11.4] vs 11.6 [10.3, 12.9] μmol/kg/min, P = .004) when the usual therapy was discontinued and replaced with insulin. Increased daytime glucose Rd (21.2 [19.4, 23.9] vs 18.8 [18.3, 21.7] μmol/kg/min, P = .002) and decreased overnight Rd (10.4 [9.1, 12.0] vs 11.8 [10.7, 13.7] μmol/kg/min, P = .005) were observed when the usual therapy was discontinued, whereas daytime peripheral insulin sensitivity was reduced (47.8 [24.8, 66.1] vs 62.5 [34.8, 75.8] nmol/kg/min per pmol/L, P = .034).

CONCLUSION

In T2D, acute discontinuation of anti-hyperglycemic therapy and replacement with insulin increases postprandial Ra and reduces peripheral insulin sensitivity. Insulin dose initiation may need to compensate for these alterations.

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.

Pharmacokinetic and toxicological considerations for the treatment of diabetes in patients with liver disease

INTRODUCTION

Patients with type 2 diabetes have an increased risk of chronic liver disease (CLD) such as non-alcoholic fatty liver disease and steatohepatitis and about one-third of cirrhotic patients have diabetes. However, the use of several antidiabetic agents may be a cause for concern in the case of hepatic impairment (HI).

AREAS COVERED

An extensive literature search was performed to analyze the influence of HI on the pharmacokinetics (PK) of glucose-lowering agents and the potential consequences for clinical practice as far as the efficacy/safety balance of their use in diabetic patients with CLD is concerned.

EXPERT OPINION

Almost no PK studies have been published regarding metformin, sulfonylureas, thiazolidinediones and α-glucosidase inhibitors in patients with HI. Only mild changes in PK of glinides, dipeptidyl peptidase-4 inhibitors and sodium glucose cotransporters type 2 inhibitors were observed in dedicated PK studies in patients with various degrees of HI, presumably without major clinical relevance although large clinical experience is lacking. Glucagon-like peptide-1 receptor agonists have a renal excretion rather than liver metabolism. Rare anecdotal case reports of hepatotoxicity have been described with various glucose-lowering agents contrasting with numerous reassuring data. Nevertheless, caution should be recommended, especially in patients with advanced cirrhosis, including with the use of metformin.

The dipeptidyl peptidase-4 inhibitor vildagliptin does not affect ex vivo cytokine response and lymphocyte function in patients with type 2 diabetes mellitus

AIMS

The enzyme dipeptidyl peptidase-4 (DPP-4) is a key player in the degradation of incretin hormones that are involved in glucose metabolism. DPP-4 is also expressed on immune cells and is associated with several immunological functions. Some studies have reported increased rates of infections in patients treated with DPP-4 inhibitors. We therefore assessed whether treatment with the DPP-4 inhibitor vildagliptin affected cytokine production and T-cell differentiation.

METHODS

Patients with type 2 diabetes were treated with vildagliptin or an active comparator, acarbose, for four weeks, in a randomized cross-over trial. Blood was sampled at the end of each treatment period and peripheral blood mononuclear cells were isolated and stimulated with a broad spectrum of pattern recognition receptor agonists.

RESULTS

Serum cytokine concentrations and ex vivo cytokine production (both monocyte and T-cell derived) did not differ during treatment with vildagliptin compared to acarbose. Similarly, ex vivo relative upregulation of mRNA transcription of T-cell lineage specific transcription factors was unaffected by vildagliptin treatment.

CONCLUSIONS

These data show that a four-week treatment with vildagliptin in patients with type 2 diabetes mellitus does not result in a significant modulation of cytokine responses. This observation suggests that inhibition of DDP-4 does not lead to an increased risk of infection by diminishing cytokine production.

Sex differences in type 2 diabetes: focus on disease course and outcomes

BACKGROUND

Women with type 2 diabetes (T2D) are less likely to reach the goals for hemoglobin A1c compared with men, and have higher all-cause mortality. The risk of cardiovascular disease is elevated among both men and women with T2D, however, the risk has declined among men over recent years while it remains stationary in women. Reasons for these sex differences remain unclear, and guidelines for diabetes treatment do not differentiate between sexes. Possible causes for varying outcome include differences in physiology, treatment response, and psychological factors. This review briefly outlines sex differences in hormonal pathophysiology, and thereafter summarizes the literature to date on sex differences in disease course and outcome.

METHODS

Systematic searches were performed on PubMed using "sex", "gender", and various glucose-lowering therapies as keywords. Earlier reviews are summarized and results from individual studies are reported. Reference lists from studies were used to augment the search.

RESULTS

There is an increased risk of missing the diagnosis of T2D when screening women with only fasting plasma glucose instead of with an oral glucose tolerance test. The impact of various risk factors for complications may differ by sex. Efficacy and side effects of some glucose-lowering drugs differ between men and women. Men with T2D appear to suffer more microvascular complications, while women have higher morbidity and mortality in cardiovascular disease and also fare worse psychologically.

CONCLUSION

Few studies to date have focused on sex differences in T2D. Several questions demand further study, such as whether risk factors and treatment guidelines should be sex-specific. There is a need for clinical trials designed specifically to evaluate sex differences in efficacy and outcome of the available treatments.

Glucose-lowering drugs in patients with chronic kidney disease: a narrative review on pharmacokinetic properties

The achievement of a good glycaemic control is one of the cornerstones for preventing and delaying progression of microvascular and macrovascular complications in patients with both diabetes and chronic kidney disease (CKD). As for other drugs, the presence of an impaired renal function may significantly affect pharmacokinetics of the majority of glucose-lowering agents, thus exposing diabetic CKD patients to a higher risk of side effects, mainly hypoglycaemic episodes. As a consequence, a reduction in dosing and/or frequency of administration is necessary to keep a satisfactory efficacy/safety profile. In this review, we aim to summarize the pharmacology of the most widely used glucose-lowering agents, discuss whether and how it is altered by a reduced renal function, and the recommendations that can be made for their use in patients with different degrees of CKD.

Cardiovascular effects of dipeptidyl peptidase-4 inhibitors: from risk factors to clinical outcomes

Dipeptidyl peptidase-4 (DPP-4) inhibitors (gliptins) are oral incretin-based glucose-lowering agents with proven efficacy and safety in the management of type 2 diabetes mellitus (T2DM). In addition, preclinical data and mechanistic studies suggest a possible additional non-glycemic beneficial action on blood vessels and the heart, via both glucagon-like peptide-1-dependent and glucagon-like peptide-1-independent effects. As a matter of fact, DPP-4 inhibitors improve several cardiovascular risk factors: they improve glucose control (mainly by reducing the risk of postprandial hyperglycemia) and are weight neutral; may lower blood pressure somewhat; improve postprandial (and even fasting) lipemia; reduce inflammatory markers; diminish oxidative stress; improve endothelial function; and reduce platelet aggregation in patients with T2DM. In addition, positive effects on the myocardium have been described in patients with ischemic heart disease. Results of post hoc analyses of phase 2/3 controlled trials suggest a possible cardioprotective effect with a trend (sometimes significant) toward lower incidence of major cardiovascular events with sitagliptin, vildagliptin, saxagliptin, linagliptin, or alogliptin compared with placebo or other active glucose-lowering agents. However, the definite relationship between DPP-4 inhibition and better cardiovascular outcomes remains to be proven. Major prospective clinical trials involving various DPP-4 inhibitors with predefined cardiovascular outcomes are under way in patients with T2DM and a high-risk cardiovascular profile: the Sitagliptin Cardiovascular Outcome Study (TECOS) on sitagliptin, the Saxagliptin Assessment of Vascular Outcomes Recorded in Patients With Diabetes Mellitus-Thrombolysis in Myocardial Infarction (SAVOR-TIMI) 53 trial on saxagliptin, the Cardiovascular Outcomes Study of Alogliptin in Subjects With Type 2 Diabetes and Acute Coronary Syndrome (EXAMINE) trial on alogliptin, and the Cardiovascular Outcome Study of Linagliptin Versus Glimepiride in Patients With Type 2 Diabetes (CAROLINA) on linagliptin. If these trials confirm that a DPP-4 inhibitor can reduce the cardiovascular burden of T2DM, it would be major progress that would dramatically influence the management of the disease.

Vildagliptin in the Treatment of Type 2 Diabetes Mellitus

Novel therapeutic approaches are continuously being researched in type 2 diabetes. The incretin class of anti-diabetic agents, consisting of glucagon-like peptide-1 agonists and dipeptidyl peptidase-4 inhibitors, has already found an important place in the current guidelines. Vildagliptin is a potent dipeptidyl peptidase-4 inhibitor, with numerous trials in type 2 diabetes treatment, both in monotherapy and in combination therapy. This review focuses on vildagliptin pharmacological properties, clinical efficacy and safety, and pharmacoeconomic data.

Pharmacokinetic considerations for the treatment of diabetes in patients with chronic kidney disease

INTRODUCTION

People with chronic kidney disease (CKD) of stages 3 - 5 (creatinine clearance < 60 ml/min) represent ≈ 25% of patients with type 2 diabetes mellitus (T2DM), but the problem is underrecognized or neglected in clinical practice. However, most oral antidiabetic agents have limitations in case of renal impairment (RI), either because they require a dose adjustment or because they are contraindicated for safety reasons.

AREAS COVERED

The author performed an extensive literature search to analyze the influence of RI on the pharmacokinetics (PK) of glucose-lowering agents and the potential consequences for clinical practice.

EXPERT OPINION

As a result of PK interferences and for safety reasons, the daily dose should be reduced according to glomerular filtration rate (GFR) or even the drug is contraindicated in presence of severe CKD. This is the case for metformin (risk of lactic acidosis) and for many sulfonylureas (risk of hypoglycemia). At present, however, the exact GFR cutoff for metformin use is controversial. New antidiabetic agents are better tolerated in case of CKD, although clinical experience remains quite limited for most of them. The dose of DPP-4 inhibitors should be reduced (except for linagliptin), whereas both the efficacy and safety of SGLT2 inhibitors are questionable in presence of CKD.

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.

Managing diabetic patients with moderate or severe renal impairment using DPP-4 inhibitors: focus on vildagliptin

BACKGROUND

Dipeptidyl peptidase-4 (DPP-4) inhibitors are novel classified oral anti-diabetic drugs for the treatment of type 2 diabetes mellitus (T2DM) that provide important reduction in glycated hemoglobin, with a low risk for hypoglycemia and no weight gain. In T2DM patients with reduced renal function, adequate glycemic control is essential to delay the progress of kidney dysfunction, but they are at a greater risk of experiencing hypoglycemic events, especially with longer-acting sulfonylureas and meglitinides.

OBJECTIVE

To evaluate vildagliptin as an option to achieve glycemic control in T2DM patients with moderate or severe chronic kidney disease (CKD).

METHODS

A comprehensive search in the literature was performed using the term "vildagliptin." Original articles and reviews exploring our topic were carefully selected.

RESULTS

Vildagliptin provides effective glycemic control in patients with T2DM and CKD. Dose reductions are required for vildagliptin and other DPP-4 inhibitors, except linagliptin, in T2DM patients with moderate-to-severe CKD. Dose of vildagliptin had to be reduced by half (to 50 mg/day) both for moderate (estimated glomerular filtration rate [eGFR] ≥30 to ≤50 mL/min) and severe CKD (eGFR < 30 mL/min). Available results support a favorable efficacy, safety, and tolerability profile for vildagliptin in T2DM with moderate or severe renal failure. Preliminary data may suggest additional benefits beyond improvement of glycemic control.

CONCLUSION

Vildagliptin can be safely used in T2DM patients with varying degrees of renal impairment. Dose adjustments for renal impairment are required. Potential long-term renal benefit of vildagliptin needs to be further explored.

A review of the efficacy and safety of oral antidiabetic drugs

INTRODUCTION

Additional oral antidiabetic agents to metformin, sulfonylureas (SU) and thiazolidinediones (TZD) are approved for the treatment of type 2 diabetes.

AREAS COVERED

The efficacy and safety of metformin, SUs, TZDs, dipeptidyl peptidase-IV (DPP-4) inhibitors, meglitinide analogs, α-glucosidase inhibitors (AGIs), bile-acid sequestrants (BAS) and bromocriptine will be reviewed.

EXPERT OPINION

Several new oral agents have been approved for type 2 diabetes management in recent years. It is important to understand the efficacy and safety of these medications in addition to the older agents to best maximize oral drug therapy for diabetes. Of the recently introduced oral hypoglycemic/antihyperglycemic agents, the DPP-4 inhibitors are moderately efficacious compared with mainstay treatment with metformin with a low side-effect profile and have good efficacy in combination with other oral agents and insulin. They are a recommended alternative when metformin use is limited by gastrointestinal (GI) side effects or when SU treatment results in significant hypoglycemia or weight gain. Meglitinide analogs are limited by their frequent dosing, expense and hypoglycemia (repaglinide > nateglinide), while AGIs are also limited by their dosing schedule and GI side-effect profile. BAS and bromocriptine have the lowest efficacy with regard to HbA(1c) reduction, also are plagued by GI adverse reactions, but have a low risk of hypoglycemia.

One-year safety, tolerability and efficacy of vildagliptin in patients with type 2 diabetes and moderate or severe renal impairment

AIM

Assess long-term safety and efficacy of the dipeptidlyl peptidase-4 (DPP-4) inhibitor vildagliptin in 369 patients with type 2 diabetes mellitus (T2DM) and moderate or severe renal impairment (RI).

METHODS

Double-blind, randomized, parallel-group, 52-week clinical trial comparing safety and efficacy of vildagliptin (50 mg qd, n = 216) and placebo (n = 153) added to ongoing stable antihyperglycaemic treatment, in patients with T2DM and moderate or severe (glomerular filtration rate [GFR] ≥ 30 to <50 ml/min/1.73 m(2) and < 30 ml/min/1.73 m(2) ) RI.

RESULTS

The study population comprised 122 and 89 patients with moderate RI and 94 and 64 patients with severe RI randomized to vildagliptin and placebo, respectively, with the majority of patients receiving background insulin therapy (72% and 82% for moderate and severe RI, respectively). After 1 year, the between-treatment difference in adjusted mean change in A1C was -0.4 ± 0.2% (p = 0.005) in moderate RI (baseline = 7.8%) and -0.7 ± 0.2% (p < 0.0001) in severe RI (baseline = 7.6%). In patients with moderate RI, similar proportions of patients experienced any adverse event (AE) (84 vs. 85%), any serious adverse event (SAE) (21 vs. 19%), any AE leading to discontinuation (5% vs. 6%) and death (1% vs. 0%) with vildagliptin and placebo, respectively. This was also true for patients with severe RI: AEs (85% vs. 88%), SAEs (25% vs. 25%), AEs leading to discontinuation (10% vs. 6%) and death (3% vs. 2%).

CONCLUSIONS

In patients with T2DM and moderate or severe RI, vildagliptin added to ongoing antidiabetic therapy had a safety profile similar to placebo during 1-year observation. Furthermore, relative to placebo, a clinically significant decrease in A1C was maintained throughout 1-year treatment with vildagliptin.