Dipeptidylpeptidase-4 inhibitors (gliptins): focus on drug-drug interactions

The efficacy and safety of vildagliptin in patients with type 2 diabetes: a meta-analysis of randomized clinical trials

WHAT IS KNOWN AND OBJECTIVE

Dipeptidyl peptidase-4 (DPP-4) inhibitors are a relatively new class of drugs for the management of type 2 diabetes (T2DM). Vildagliptin is an oral DPP-4 inhibitor approved in more than 70 countries. The purpose of this meta-analysis is to provide an update on the clinical efficacy and safety of vildagliptin in patients with T2DM.

METHODS

A literature search identified 30 randomized controlled trials comparing vildagliptin with comparators (placebo or other hypoglycaemic agents). Meta-analyses were conducted for HbA1c, weight, fasting plasma glucose (FPG), hypoglycaemia and other adverse events. The outcomes of HbA1c, weight and FPG were analysed as weighted mean differences (WMD), and the number of ADRs events as relative risks (RR).

RESULTS

Compared with placebo, vildagliptin lowered HbA1c {WMD, -0·77% [95% confidence interval (CI), -0·96% to -0·58%] for 100 mg/day of vildagliptin and -0·58% [95% CI, -0·72% to -0·44%] for 50 mg/day of vildagliptin}. The effect was non-inferior to thiazolidinediones, sulfonylureas and α-glycosidase inhibitors, but inferior to metformin. Compared with placebo, treatment with 50 mg/day of vildagliptin caused neutral weight changes, while 100 mg/day of vildagliptin resulted in slight weight gain [0·95 kg (95% CI, 0·73-1·17 kg)]. In addition, compared to comparators, vildagliptin was not associated with an increase in overall risk for any adverse events [RR, 0·97 (95% CI, 0·94-0·99)]. The incidence of hypoglycaemia was low with vildagliptin, and the risk with vildagliptin was not significantly different from the comparators [0·85 (95% CI, 0·49-1·47)]. The use of vildagliptin did not display any increased risks of infection [1·03 (95% CI, 0·94-1·13) for nasopharyngitis and 1·07 (95% CI, 0·90-1·27) for upper respiratory tract infection].

WHAT IS NEW AND CONCLUSION

Vildagliptin is effective in glycaemic control with a low risk of hypoglycaemia and other adverse reactions. This may have an important impact on patient adherence to this medication.

Tolerability of dipeptidyl peptidase-4 inhibitors: a review

BACKGROUND

Oral glucose-lowering agents are used to treat patients with type 2 diabetes mellitus (T2DM). Most patients require multiple agents to maintain glycemic targets. Dipeptidyl peptidase-4 (DPP-4) inhibitors are administered as monotherapy and in combination therapy for the treatment of T2DM.

OBJECTIVE

The aim of this article was to provide a thorough review of published tolerability data on 5 DPP-4 inhibitors.

METHODS

PubMed and Web of Science were searched for English-language clinical trials published from January 2000 to June 2001, using the following key words: dipeptidyl peptidase-4 inhibitor, vildagliptin, alogliptin, sitagliptin, saxagliptin, linagliptin, safety, tolerability, efficacy, effect, AE, and adverse effect. Studies were considered for inclusion if they were randomized, double-blind trials performed in patients ≥18 years of age with T2DM and with a hemoglobin A(1c) of ≥6.5%; included ≥1 arm that received monotherapy with DPP-4; and reported adverse events (AEs). Studies in patients with a history of type 1 or secondary forms of diabetes, significant diabetic complications or cardiovascular disease within the 6 months before the start of the study, hepatic disease or abnormalities, and/or renal abnormalities were excluded.

RESULTS

A total of 45 clinical trials, 5 pharmacokinetic studies, and 28 meta-analyses or reviews were included. The duration of studies ranged from 7 days to 104 weeks. The most commonly reported AEs were nasopharyngitis, upper respiratory infections, all-cause infections, headache, gastrointestinal symptoms, and musculoskeletal pain. Based on the findings from the studies, the DPP-4 inhibitors had minimal impact on weight and were not associated with an increased risk for hypoglycemia relative to placebo. Rates of nasopharyngitis were higher with the DDP-4 inhibitors than with placebo. Pancreatitis was reported at lower rates with the DPP-4 inhibitors compared with other oral antihyperglycemic agents. Cardiovascular events were limited, and postmarketing studies are ongoing.

CONCLUSIONS

The tolerability of DPP-4 inhibitors is supported by published clinical trials. The rates of weight gain, gastrointestinal AEs, and hypoglycemia were minimal with the DPP-4 inhibitors studied.

Linagliptin

Each month, subscribers to The Formulary Monograph Service receive 5 to 6 well-documented monographs on drugs that are newly released or are in late phase 3 trials. The monographs are targeted to Pharmacy & Therapeutics Committees. Subscribers also receive monthly 1-page summary monographs on agents that are useful for agendas and pharmacy/nursing in-services. A comprehensive target drug utilization evaluation/medication use evaluation (DUE/MUE) is also provided each month. With a subscription, the monographs are sent in print and are also available on-line. Monographs can be customized to meet the needs of a facility. Subscribers to The Formulary Monograph Service also receive access to a pharmacy bulletin board, The Formulary Information Exchange (The F.I.X.). All topics pertinent to clinical and hospital pharmacy are discussed on The F.I.X. Through the cooperation of The Formulary, Hospital Pharmacy publishes selected reviews in this column. For more information about The Formulary Monograph Service or The F.I.X., call The Formulary at 800-322-4349. The September 2011 monograph topics are on rivaroxaban, ezogabine, fentanyl nasal spray, belatacept, and nitroglycerin ointment 0.4%. The DUE/MUE is on rivaroxaban.

Cytochrome P450-mediated cardiovascular drug interactions

INTRODUCTION

There are numerous drug-drug interactions (DDIs) related to cardiovascular medications and many of these are mediated via the cytochrome P450 (CYP) system. Some of these may lead to serious adverse events and it is, therefore, essential that clinicians are aware of the important interactions that occur.

AREAS COVERED

An extensive literature search was performed to analyze the CYP-mediated cardiovascular DDIs that lead to a loss of efficacy or potential toxicity. Cardiovascular drugs may be victims or act as perpetrators of DDIs. The paper analyzes CYP-mediated drug interactions concerning anticoagulants, antiplatelet agents, antiarrhythmics, β-blockers, calcium antagonists, antihypertensive medications, lipid-lowering drugs and oral antidiabetic agents.

EXPERT OPINION

Cardiovascular DDIs involving the CYP system are numerous. Additionally, the spectrum of drugs prescribed is constantly changing, particularly with cardiovascular diseases and it is not necessarily the case that drugs that had shown safety earlier will always show safety. Clinicians are encouraged to develop their knowledge of CYP-mediated DDIs so that they can choose safe drug combination regimens, adjust drug dosages appropriately and conduct therapeutic drug monitoring for drugs with narrow therapeutic indices.

From theory to clinical practice in the use of GLP-1 receptor agonists and DPP-4 inhibitors therapy

Promoting long-term adherence to lifestyle modification and choice of antidiabetic agent with low hypoglycemia risk profile and positive weight profile could be the most effective strategy in achieving sustained glycemic control and in reducing comorbidities. From this perspective, vast interest has been generated by glucagon-like peptide-1 (GLP-1) receptor agonists and dipeptidyl peptidase-4 inhibitors (DPP-4i). In this review our ten-year clinical and laboratory experience by in vitro and in vivo studies is reported. Herein, we reviewed available data on the efficacy and safety profile of GLP-1 receptor agonists and DPP-4i. The introduction of incretin hormone-based therapies represents a novel therapeutic strategy, because these drugs not only improve glycemia with minimal risk of hypoglycemia but also have other extraglycemic beneficial effects. In clinical studies, both GLP-1 receptor agonists and DPP-4i, improve β cell function indexes. All these agents showed trophic effects on beta-cell mass in animal studies. The use of these drugs is associated with positive or neucral effect on body weight and improvements in blood pressure, diabetic dyslipidemia, hepatic steazosis markets, and myocardial function. These effects have the potential to reduce the burden of cardiovascular disease, which is a major cause of mortality in patients with diabetes.

Linagliptin: a novel dipeptidyl peptidase 4 inhibitor with a unique place in therapy

The dipeptidyl peptidase 4 (DPP-4) inhibitors comprise a promising new class of agent for the management of type 2 diabetes. They possess a range of physiological effects associated with improved glycemic control including stimulation of glucose-dependent insulin secretion and suppression of glucagon secretion, and lower blood glucose levels through different, but potentially complementary, mechanisms to standard oral therapies. Linagliptin is the latest DPP-4 inhibitor to complete pivotal phase 3 trials. The data show that linagliptin provides significant, clinically meaningful and sustained improvements in glycemic control, with an incidence of adverse events similar to placebo and an excellent tolerability profile. In addition, linagliptin has been shown to be weight neutral and, importantly, there was no increased risk of hypoglycemia attributed to linagliptin use in monotherapy or combination therapy with metformin or pioglitazone. A unique characteristic of linagliptin that differentiates it from other members of the class is its primarily nonrenal route of excretion. The linagliptin phase 3 program included several hundred patients with type 2 diabetes and different stages of renal disease and the data suggest that the drug would not need dose adjustment, regardless of the degree of renal impairment. There is a particular need for safe and effective therapeutic agents that can be used when renal function declines. Linagliptin has recently been approved by the US Food and Drug Administration and may find a place in therapy as a treatment option for the significant number of patients in whom metformin and the other DPP-4 inhibitors are either contraindicated or require dose adjustment because of moderate to severe renal impairment.

Vildagliptin: a review of its use in type 2 diabetes mellitus

Vildagliptin (Galvus®, Jalra®, Xiliarx®) is an orally administered dipeptidyl peptidase-4 (DPP-4) inhibitor. In patients with type 2 diabetes mellitus, vildagliptin 50 mg twice daily is indicated for use in combination with metformin or a thiazolidinedione, and vildagliptin 50 mg once daily is indicated for use in combination with a sulfonylurea. A fixed-dose combination of vildagliptin/metformin (Eucreas®, Icandra®, Zomarist®) is also available. This article reviews the clinical efficacy and tolerability of vildagliptin in patients with type 2 diabetes, as well as summarizing its pharmacological properties. The efficacy of monotherapy or combination therapy with oral vildagliptin in patients with type 2 diabetes has been examined in randomized, double-blind, multicentre trials. Monotherapy with vildagliptin 50 mg once or twice daily reduced glycosylated haemoglobin (HbA(1c)) from baseline to a significantly greater extent than placebo, according to the results of 12- to 52-week trials in patients with type 2 diabetes. In terms of the reduction from baseline in HbA(1c) seen in active comparator trials of 12-104 weeks' duration, the noninferiority of vildagliptin 50 mg twice daily was established versus acarbose or rosiglitazone, the noninferiority of vildagliptin 100 mg once daily (an off-label dosage) versus metformin was established in elderly patients and vildagliptin 50 mg twice daily was more effective than voglibose; however, the noninferiority of vildagliptin 50 mg twice daily versus metformin or gliclazide was not established in two other trials. Combination therapy with vildagliptin 50 mg twice daily plus metformin improved HbA(1c) to a significantly greater extent than monotherapy with metformin and/or vildagliptin alone in patients with type 2 diabetes whose disease was inadequately controlled by metformin monotherapy or who were treatment naive, according to the results of 12- or 24-week trials. In addition, vildagliptin 50 mg twice daily plus metformin demonstrated noninferiority to pioglitazone plus metformin, glimepiride plus metformin or gliclazide plus metformin in terms of the change from baseline in HbA(1c) after 24 or 52 weeks' therapy in patients with inadequately controlled type 2 diabetes. The addition of vildagliptin 50 mg twice daily to pioglitazone or vildagliptin 50 mg once daily to glimepiride improved HbA(1c) to a significantly greater extent than a thiazolidinedione or glimepiride alone in patients with type 2 diabetes whose disease was inadequately controlled, according to the results of 24-week trials. Oral vildagliptin 50 mg once or twice daily was generally well tolerated in patients with type 2 diabetes. In particular, vildagliptin was associated with a low risk of hypoglycaemia and was weight neutral. Increases in transaminase levels were sometimes observed with a vildagliptin dosage of 100 mg once daily in clinical trials, and liver function should be monitored in patients receiving vildagliptin. However, meta-analyses of clinical trial data suggested that vildagliptin 50 mg once or twice daily was not associated with an increased risk of hepatic adverse events, transaminase elevations ≥3 × the upper limit of normal, pancreatitis, cardiovascular or cerebrovascular events, infections or skin-related toxicity. In conclusion, vildagliptin is an important option for use in combination with metformin, a sulfonylurea or a thiazolidinedione in patients with type 2 diabetes who require combination therapy.

Drug-induced bullous pemphigoid in diabetes mellitus patients receiving dipeptidyl peptidase-IV inhibitors plus metformin

BACKGROUND

Preclinical data and reports of adverse skin reactions in patients treated with dipeptidyl peptidase-IV inhibitors (gliptins) have increased awareness towards skin-targeting side-effects of these anti-hyperglycaemic drugs. Bullous pemphigoid (BP), sometimes drug-induced, is the most commonly acquired autoimmune blistering dermatosis in western countries, typically a disease of the elderly people with significant morbidity and excess mortality.

OBJECTIVE

To report the development of BP in five diabetics under gliptin (4 vildagliptin, 1 sitagliptin) plus metformin in fixed-dose drug combinations.

CASE REPORTS

From March to August 2010 six out of nine newly diagnosed BP patients in our Department were type 2 diabetics. Five of them were on gliptin plus metformin (three different trade preparations) for 2-13 months prior to BP onset. In all cases BP was controlled after withdrawal of the suspected medication and relatively mild therapeutic interventions. In two cases the eliciting role of the preceding treatment is supported by evidence at the level 'probable/likely' according to the WHO-UMC algorithm.

CONCLUSIONS

This is the first report of drug-induced BP as a group adverse event of the gliptins plus metformin combination therapy for glycaemia control in type 2 diabetes mellitus patients.

Alogliptin: a review of its use in the management of type 2 diabetes mellitus

Alogliptin (Nesina®) is a dipeptidyl peptidase-4 inhibitor that is approved in Japan for the treatment of adult patients with type 2 diabetes mellitus that is inadequately controlled by diet and exercise alone or by diet plus treatment with an α-glucosidase inhibitor. Alogliptin plus diet and exercise is also approved in Japan for use in combination with a thiazolidinedione in patients with type 2 diabetes. In several large (n >250), double-blind, multinational trials of up to 26 weeks' duration, oral alogliptin as monotherapy or in combination with other oral antihyperglycaemic agents (metformin, glibenclamide or pioglitazone) or insulin therapy improved glycaemic control and was generally well tolerated in adult patients with inadequately controlled type 2 diabetes, including elderly patients. Significant improvements in glycaemic control were evident from as early as 1 week in terms of improvements in mean fasting plasma glucose levels and from 4 weeks onwards for improvements in mean glycosylated haemoglobin levels. In general, the incidence of hypoglycaemia was similar to that seen in placebo groups and alogliptin treatment had neutral effects on bodyweight and lipid parameters. The long-term safety of alogliptin therapy remains to be established in clinical studies and with clinical experience. A planned clinical trial evaluating long-term clinical outcomes in patients with acute coronary syndrome and other planned or ongoing short-term trials will help to more definitively determine the position of alogliptin therapy in relation to other available antihyperglycaemic therapies. In the meantime, alogliptin is a promising new option for the treatment of patients with type 2 diabetes, including elderly patients.

Pharmacokinetic and pharmacodynamic evaluation of sitagliptin plus metformin

IMPORTANCE OF THE FIELD

Type 2 diabetes is an increasingly prevalent disease resulting from various complex combinations of defects in insulin secretion and insulin action. Adequate blood glucose control is necessary to minimize complications. DPP IV inhibitors (sitagliptin, vildagliptin, saxagliptin) offer new options for combined pharmacological therapy.

AREAS COVERED IN THIS REVIEW

An extensive literature search was performed to analyze the potential pharmacokinetic (PK) and pharmacodynamic (PD) interactions between metformin (first-line drug for the management of type 2 diabetes) and sitagliptin (first commercialized DPP IV inhibitor). Metformin and sitagliptin may be administered together, either separately or in fixed-dose combination.

WHAT THE READER WILL GAIN

Updated information about PK/PD data on metformin alone, sitagliptin alone and sitagliptin plus metformin. Metformin and sitagliptin are not prone to PK drug-drug interactions. Their co-administration, either separately or in a fixed-dose combination, improves blood glucose control more potently than either compound separately, without hypoglycemia and without increasing metformin-related gastrointestinal side effects.

TAKE HOME MESSAGE

The combination sitagliptin plus metformin may be used as a first- or second-line therapy in the management of type 2 diabetes.

Pharmacokinetics of dipeptidylpeptidase-4 inhibitors

Type 2 diabetes (T2DM) is a complex disease combining defects in insulin secretion and insulin action. New compounds have been developed for improving glucose-induced insulin secretion and glucose control, without inducing hypoglycaemia or weight gain. Dipeptidylpeptidase-4 (DPP-4) inhibitors are new oral glucose-lowering agents, so-called incretin enhancers, which may be used as monotherapy or in combination with other antidiabetic compounds. Sitagliptin, vildaglipin and saxagliptin are already on the market in many countries, either as single agents or in fixed-dose combined formulations with metformin. Other DPP-4 inhibitors, such as alogliptin and linagliptin, are currently in late phase of development. The present paper summarizes and compares the main pharmacokinetics (PK) properties, that is, absorption, distribution, metabolism and elimination, of these five DPP-4 inhibitors. Available data were obtained in clinical trials performed in healthy young male subjects, patients with T2DM, and patients with either renal insufficiency or hepatic impairment. PK characteristics were generally similar in young healthy subjects and in middle-aged overweight patients with diabetes. All together gliptins have a good oral bioavailability which is not significantly influenced by food intake. PK/pharmacodynamics characteristics, that is, sufficiently prolonged half-life and sustained DPP-4 enzyme inactivation, generally allow one single oral administration per day for the management of T2DM; the only exception is vildagliptin for which a twice-daily administration is recommended because of a shorter half-life. DPP-4 inhibitors are in general not substrates for cytochrome P450 (except saxagliptin that is metabolized via CYP 3A4/A5) and do not act as inducers or inhibitors of this system. Several metabolites have been documented but most of them are inactive; however, the main metabolite of saxagliptin also exerts a significant DPP-4 inhibition and is half as potent as the parent compound. Renal excretion is the most important elimination pathway, except for linagliptin whose metabolism in the liver appears to be predominant. PK properties of gliptins, combined with their good safety profile, explain why no dose adjustment is necessary in elderly patients or in patients with mild to moderate hepatic impairment. As far as patients with renal impairment are concerned, significant increases in drug exposure for sitagliptin and saxagliptin have been reported so that appropriate reductions in daily dosages are recommended according to estimated glomerular filtration rate. The PK characteristics of DPP-4 inhibitors suggest that these compounds are not exposed to a high risk of drug-drug interactions. However, the daily dose of saxagliptin should be reduced when coadministered with potent CYP 3A4 inhibitors. In conclusion, besides their pharmacodynamic properties leading to effective glucose-lowering effect without inducing hypoglycaemia or weight gain, DPP-4 inhibitors show favourable PK properties, which contribute to a good efficacy/safety ratio for the management of T2DM in clinical practice.