Pharmacology of dipeptidyl peptidase-4 inhibitors: similarities and differences

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.

Asymmetric synthesis of γ-chloro-α,β-diamino- and β,γ-aziridino-α-aminoacylpyrrolidines and -piperidines via stereoselective Mannich-type additions of N-(diphenylmethylene)glycinamides across α-chloro-N-sulfinylimines

The asymmetric synthesis of new chiral γ-chloro-α,β-diaminocarboxylamide derivatives by highly diastereoselective Mannich-type reactions of N-(diphenylmethylene)glycinamides across chiral α-chloro-N-p-toluenesulfinylaldimines was developed. The resulting (S_S,2S,3S)-γ-chloro-α,β-diaminocarboxylamides were formed with the opposite enantiotopic face selectivity as compared to the (S_S,2R,3R)-γ-chloro-α,β-diaminocarboxyl esters obtained via Mannich-type addition of analogous N-(diphenylmethylene)glycine esters across a chiral α-chloro-N-p-toluenesulfinylaldimine. Selective deprotection under different acidic reaction conditions and ring closure of the γ-chloro-α,β-diaminocarboxylamides was optimized, which resulted in N^α-deprotected syn-γ-chloro-α,β-diaminocarboxylamides, N-sulfinyl-β,γ-aziridino-α-aminocarboxylamide derivatives, a trans-imidazolidine, and an N^α,N^β-deprotected syn-γ-chloro-α,β-diaminocarboxylamide.

Saxagliptin overview: special focus on safety and adverse effects

INTRODUCTION

Saxagliptin (see drug summary box) is a glucose-lowering agent that belongs to the class of Dipeptidylpeptidase-4 (DDP-4) inhibitors used in the treatment of T2DM. Clinical efficacy of saxagliptin as single agent as well as in combination with other medications used for the treatment of T2DM has been well established in several randomized trials. Treatment with saxagliptin is effective, generally safe and well tolerated, apart from a small increase in the incidence of infections such as nasopharyngitis. Its use is not associated with increase risk of hypoglycemia and it is weight neutral. Saxagliptin can be used safely in renal failure (with dose adjustment) and in hepatic impairment. When saxagliptin is used in combination with a strong inhibitor of CYP3A4/A5, reduction in the daily dosage is recommended.

AREAS COVERED

This paper briefly discusses efficacy and pharmacokinetics of saxagliptin. The paper highlights in detail saxagliptin-associated adverse effects, drug interactions, its use in patients with renal and hepatic disease and long-term safety concerns.

EXPERT OPINION

Saxagliptin has comparable efficacy with other DPP-4 inhibitors. It is generally safe and well tolerated; however, it requires dose adjustment in renal disease as well as when used with drugs that are strong inhibitor or inducer of CYP3A4/A5 isoforms. Future safety questions regarding immune system and development of cancer still remain to be completely answered.

Efficacy and safety of dipeptidyl peptidase-4 inhibitors in type 2 diabetes: meta-analysis

BACKGROUND

An up-to-date assessment of dipeptidyl peptidase-4 (DPP-4) inhibitors is needed to include newly available data.

OBJECTIVE

To assess the efficacy and safety of DPP-4 inhibitors, including sitagliptin, saxagliptin, vildagliptin, and linagliptin, in type 2 diabetes.

METHODS

We conducted a search of MEDLINE for randomized controlled trials (RCTs) of DPP-4 inhibitors in type 2 diabetes through November 2011, using the key terms sitagliptin, saxagliptin, vildagliptin, and linagliptin. We also searched for completed, but unpublished, trials at relevant web sites. RCTs were selected for meta-analysis if they (1) compared DPP-4 inhibitors with placebo or an antihyperglycemic agent; (2) had study duration of 12 or more weeks; (3) had 1 or more baseline and posttreatment efficacy and/or safety outcome; and (4) were published in English.

RESULTS

In 62 evaluated articles, DPP-4 inhibitors lowered hemoglobin A(1c) (A1C) significantly more than placebo (weighted mean difference [WMD] -0.76%; 95% CI -0.83 to -0.68); however, heterogeneity was substantial (I(2) = 82%). Exclusion of Japanese trials (n = 7) resulted in a reduction of heterogeneity (I(2) = 59%). In the non-Japanese RCTs (n = 55), DPP-4 inhibitors were associated with a reduction in A1C (WMD -0.65%; 95% CI -0.71 to -0.60) but higher risk of hypoglycemia (odds ratio [OR] 1.30; 95% CI 1.00 to 1.68) compared to placebo. The 7 Japanese-specific RCTs showed a greater reduction in A1C (WMD -1.67%; 95% CI -1.89 to -1.44) and a nonsignificant increase in risk of hypoglycemia (OR 1.41; 95% CI 0.51 to 3.88) with DPP-4 inhibitors versus placebo. When comparing DPP-4 inhibitors to active comparators, the I(2) was still high after deleting Japanese studies. In these 17 active comparator trials, there was no significant difference in A1C reduction (WMD 0.04%; 95% CI -0.09 to 0.16) or risk of hypoglycemia (OR 0.60; 95% CI 0.22 to 1.61) for DPP-4 inhibitors compared to other antihyperglycemics. There were similar odds of any or serious adverse events with DPP-4 inhibitors compared to placebo, but a decreased risk compared to other antihyperglycemics.

CONCLUSIONS

DPP-4 inhibitors were associated with a reduction in A1C with comparable safety profiles compared to placebo, but no significant difference in A1C compared to other hyperglycemics. Differences in efficacy and safety were observed between Japanese and non-Japanese patients.

Comparative clinical pharmacokinetics of dipeptidyl peptidase-4 inhibitors

Dipeptidyl peptidase-4 (DPP-4) inhibitors collectively comprise a presently unique form of disease management for persons with type 2 diabetes mellitus. The aim of this review is to compare the clinical pharmacokinetics of available DPP-4 inhibitors (alogliptin, linagliptin, saxagliptin, sitagliptin and vildagliptin) for the purpose of identifying potential selection preferences according to individual patient variables and co-morbidities. DPP-4 inhibitors are readily absorbed orally. Following oral ingestion, absorption occurs mainly in the small intestine, with median times to maximum (peak) plasma concentration ranging from 1 to 3 hours. The fraction of each dose absorbed ranges from approximately 30% with linagliptin to 75-87% for all others. Numerical differences in maximum (peak) plasma drug concentrations and areas under the plasma concentration-time curve among the DPP-4 inhibitors vary by an order of magnitude. However, functional capacity measured in terms of glucose-lowering ability remains comparable among all available DPP-4 inhibitors. Distribution of DPP-4 inhibitors is strongly influenced by both lipophilicity and protein binding. Apparent volumes of distribution (V(d)) for most agents range from 70 to 300 L. Linagliptin exhibits a V(d) of more than 1000 L, indicating widespread distribution into tissues. Binding to target proteins in plasma and peripheral tissues exerts a major influence upon broadening linagliptin distribution. DPP-4 inhibitor metabolism is widely variable, with reported terminal half-lives ranging from approximately 3 to more than 200 hours. Complex relationships between rates of receptor binding and dissociation appear to strongly influence the durations of action of those DPP-4 inhibitors with comparatively shorter half-lives. Durations of activity often are not reflective of clearance and, with the exception of vildagliptin which may be administered either once daily in the evening or twice daily, these medications are effective when used with a once-daily dosing schedule. Saxagliptin and, to a lesser extent, sitagliptin are largely metabolized by hepatic cytochrome P450 (CYP) 3A4 and 3A5 isoforms. With the exception of the primary hydroxylated metabolite of saxagliptin, which is 2-fold less potent than its parent molecule, metabolic products of hepatic biotransformation are minimally active and none appreciably contribute to either the therapeutic or the toxic effects of DPP-4 inhibitors. No DPP-4 inhibitor has been shown to inhibit or to induce hepatic CYP-mediated drug metabolism. Accordingly, the number of clinically significant drug-drug interactions associated with these agents is minimal, with only saxagliptin necessitating dose adjustment if administered concurrently with medications that strongly inhibit CYP3A4. Linagliptin undergoes enterohepatic cycling with a large majority (85%) of the absorbed dose eliminated in faeces via biliary excretion. Other DPP-4 inhibitors predominantly undergo renal excretion, with 60-85% of each dose eliminated as unchanged parent compound in the urine. Systematic reviews of clinical trials suggest that the overall efficacy of DPP-4 inhibitors in patients with type 2 diabetes generally is similar. Apart from these generalizations, pharmacokinetic distinctions that potentially influence product selection are tentative. When considered in total, data reviewed in this report suggest that the best overall balance between potency and the clinical pharmacokinetic characteristics of distribution, metabolism and elimination may be observed with linagliptin followed closely by vildagliptin, saxagliptin, sitagliptin and alogliptin.

Glycemic variability and glycemic control in the acutely ill cardiac patient

The mechanisms for hyperglycemia-mediated harm in the hospitalized cardiac patient are poorly understood. Potential obstacles in the inpatient management of hyperglycemia in cardiac patients include rapidly changing clinical status, frequent procedures and interruptions in carbohydrate exposure, and short hospital length of stay. A patient's preadmission regimen is rarely suitable for inpatient glycemic control. Instead, an approach to a flexible, physiologic insulin regimen is described, which is intended to minimize glycemic excursions. When diabetes or hyperglycemia is addressed early and consistently, the hospital stay can serve as a potential window of opportunity for reinforcing self-care behaviors that reduce long-term complications.

Microvesicles/exosomes as potential novel biomarkers of metabolic diseases

Biomarkers are of tremendous importance for the prediction, diagnosis, and observation of the therapeutic success of common complex multifactorial metabolic diseases, such as type II diabetes and obesity. However, the predictive power of the traditional biomarkers used (eg, plasma metabolites and cytokines, body parameters) is apparently not sufficient for reliable monitoring of stage-dependent pathogenesis starting with the healthy state via its initiation and development to the established disease and further progression to late clinical outcomes. Moreover, the elucidation of putative considerable differences in the underlying pathogenetic pathways (eg, related to cellular/tissue origin, epigenetic and environmental effects) within the patient population and, consequently, the differentiation between individual options for disease prevention and therapy - hallmarks of personalized medicine - plays only a minor role in the traditional biomarker concept of metabolic diseases. In contrast, multidimensional and interdependent patterns of genetic, epigenetic, and phenotypic markers presumably will add a novel quality to predictive values, provided they can be followed routinely along the complete individual disease pathway with sufficient precision. These requirements may be fulfilled by small membrane vesicles, which are so-called exosomes and microvesicles (EMVs) that are released via two distinct molecular mechanisms from a wide variety of tissue and blood cells into the circulation in response to normal and stress/pathogenic conditions and are equipped with a multitude of transmembrane, soluble and glycosylphosphatidylinositol-anchored proteins, mRNAs, and microRNAs. Based on the currently available data, EMVs seem to reflect the diverse functional and dysfunctional states of the releasing cells and tissues along the complete individual pathogenetic pathways underlying metabolic diseases. A critical step in further validation of EMVs as biomarkers will rely on the identification of unequivocal correlations between critical disease states and specific EMV signatures, which in future may be determined in rapid and convenient fashion using nanoparticle-driven biosensors.

Hypoglycemia in patients with type 2 diabetes from India and Malaysia treated with sitagliptin or a sulfonylurea during Ramadan: a randomized, pragmatic study

OBJECTIVE

To compare the incidence of symptomatic hypoglycemia between sitagliptin and sulfonylurea in Muslim patients with type 2 diabetes who fasted during Ramadan.

METHODS

In a multicenter, pragmatic, randomized study, patients with type 2 diabetes were recruited from clinical centers in India (n = 765) and Malaysia (n = 105). Eligible patients (age ≥ 18 yrs) expressed their intention to daytime fast during Ramadan, were treated with a stable dose of sulfonylurea with or without metformin for ≥3 months prior to screening visit, and had an HbA(1c) ≤ 10%. Patients were randomized in a 1:1 ratio to either switch to sitagliptin 100 mg q.d. or remain on their pre-study sulfonylurea. Daily diary cards were completed to document information on hypoglycemic symptoms and complications. The primary endpoint was the overall incidence of symptomatic hypoglycemia during Ramadan.

RESULTS

Of the 870 patients randomized, 848 (n = 421 for sitagliptin and 427 for sulfonylurea) returned ≥1 completed diary card and were included in the analysis. The proportion of patients who recorded ≥1 symptomatic hypoglycemic event during Ramadan was lower with sitagliptin (3.8%) compared to sulfonylurea (7.3%). The risk of symptomatic hypoglycemia was significantly lower with sitagliptin (risk ratio [95% CI] = 0.52 [0.29, 0.94]; p = 0.028). By country, the proportions of patients who recorded ≥1 symptomatic hypoglycemic event during Ramadan were 4.1% vs. 7.7% in India and 1.9% vs. 3.8% in Malaysia for sitagliptin and sulfonylurea, respectively. No patient discontinued treatment due to a hypoglycemic event. One patient on sitagliptin and seven on sulfonylurea had an event that required non-medical assistance. No events required medical assistance. Both treatments were generally well tolerated.

LIMITATIONS

Symptomatic hypoglycemic events did not require a confirmatory blood glucose measurement, which may have overestimated hypoglycemic events. Measures of glycemic control and body weight were not assessed.

CONCLUSION

Switching antihyperglycemic treatment to sitagliptin from a sulfonylurea reduced the risk of symptomatic hypoglycemia by approximately 50% for Muslim patients with type 2 diabetes who fasted during Ramadan.

CLINICAL TRIAL REGISTRATION

Clinicaltrials.gov: NCT01340768.

Clinical pharmacokinetics and pharmacodynamics of vildagliptin

Vildagliptin is an orally active, potent and selective dipeptidyl peptidase-4 (DPP-4) inhibitor, shown to be effective and well tolerated in patients with type 2 diabetes mellitus (T2DM) as either monotherapy or in combination with other anti-diabetic agents. Vildagliptin possesses several desirable pharmacokinetic properties that contribute to its lower variability and low potential for drug interaction. Following oral administration, vildagliptin is rapidly and well absorbed with an absolute bioavailability of 85%. An approximately dose-proportional increase in exposure to vildagliptin over the dose range of 25-200 mg has been reported. Food does not have a clinically relevant impact on the pharmacokinetics of vildagliptin, and it can be taken without regard to food. Vildagliptin is minimally bound to plasma proteins (9.3%) and, on the basis of a volume of distribution of 71 L, it is considered to distribute extensively into extravascular spaces. Renal clearance of vildagliptin (13 L/h) accounts for 33% of the total body clearance after intravenous administration (41 L/h). The primary elimination pathway is hydrolysis by multiple tissues/organs. The DPP-4 enzyme contributes to the formation of the major hydrolysis metabolite, LAY151; therefore, vildagliptin is also a substrate of DPP-4. Vildagliptin has a low potential for drug interactions, as cytochrome P450 (CYP) enzymes are minimally (<1.6%) involved in the overall metabolism. Clinical pharmacokinetic studies have reported the lack of drug interaction with several drugs (metformin, pioglitazone, glyburide, simvastatin, amlodipine, valsartan, ramipril, digoxin and warfarin) that are likely to be frequently co-administered to patients with T2DM. In particular, vildagliptin does not affect the pharmacokinetics of pioglitazone, glyburide, warfarin and simvastatin; therefore, it is not expected to affect the pharmacokinetics of a drug that is a substrate for CYP2C8, CYP2C9 or CYP3A4. In the elderly, vildagliptin exposure increases by approximately 30%, which is considered to be mostly attributable to compromised renal function in the elderly population and is not considered to be clinically relevant. Vildagliptin has been demonstrated to be efficacious, safe and well tolerated in elderly patients with T2DM without dose adjustment. In subjects with varying degrees of renal impairment, vildagliptin exposure increases by approximately 2-fold; however, the increase in the exposure does not correlate with the severity of renal impairment. The lack of a clear correlation between the increased exposure and the severity of renal impairment is considered to be attributable to the fact that the kidneys contribute to both the excretion and the hydrolysis metabolism of vildagliptin. Hepatic impairment, gender, body mass index (BMI) and ethnicity do not have an influence on the pharmacokinetics of vildagliptin. These findings suggest that vildagliptin can be used in a diverse patient population without dose adjustment. Oral administration of vildagliptin to patients with T2DM completely inhibits DPP-4 activity at a variety of doses. The onset of DPP-4 inhibition is rapid, and the duration of DPP-4 inhibition is dose dependent. Vildagliptin is a potent inhibitor of the DPP-4 enzyme, with a concentration required to achieve 50% DPP-4 inhibition (IC(50)) of 4.5 nmol/L in patients with T2DM. Similar potency of DPP-4 inhibition by vildagliptin has been reported in different ethnic groups, indicating that ethnicity does not affect the pharmacodynamics of vildagliptin. Vildagliptin significantly increases the active glucagon-like peptide 1 (GLP-1) levels by approximately 2- to 3-fold and glucose-dependent insulinotropic polypeptide (GIP) levels by approximately 5-fold, and significantly suppresses the postprandial glucagon levels in response to a meal or following an oral glucose tolerance test (OGTT) in patients with T2DM. Vildagliptin significantly reduces both fasting and postprandial glucose levels over the dose range of 50-100 mg daily (administered either once daily or twice daily), and there are no substantial additional benefits of doses greater than 50 mg twice daily. The primary clinical dosing regimen is 50 mg twice daily as monotherapy or in combination with metformin. Vildagliptin increases the insulin levels following an OGTT and an intravenous glucose tolerance test (IVGTT), and the stimulation of insulin secretion is glucose dependent. Vildagliptin has been shown to improve beta-cell function on the basis of pharmacodynamic modelling taking the reduced glucose levels into account. The improvement of beta-cell function by vildagliptin has been confirmed after chronic treatment with vildagliptin for up to 2 years. Reduction of the endogenous glucose production appears to contribute to the glucose-lowering effects. Unlike the GLP-1 receptor agonists, vildagliptin does not affect gastric emptying, and this is consistent with the favourable gastrointestinal safety profile. Vildagliptin improves the sensitivity of the alpha cell to glucose in patients with T2DM by enhancing the alpha-cell responsiveness to both suppressive effects of hyperglycaemia and stimulatory effects of hypoglycaemia. Consistently, a lower incidence of hypoglycaemic events with vildagliptin is reported when it is used as either monotherapy or in combination with other anti-diabetic agents, such as metformin or insulin, as compared with a sulphonylurea. Numerous long-term clinical trials of up to 2 years have demonstrated that vildagliptin 50 mg once daily or twice daily is effective, safe and well tolerated in patients with T2DM as either monotherapy or in combination with a variety of other anti-diabetic agents.

Saxagliptin: a review of its use as combination therapy in the management of type 2 diabetes mellitus in the EU

Saxagliptin (Onglyza™) is a dipeptidyl peptidase 4 inhibitor widely approved for the treatment of type 2 diabetes mellitus. In the EU, saxagliptin is indicated as combination therapy with metformin, a sulfonylurea, a thiazolidinedione, or insulin (with or without metformin) for the treatment of adult patients with type 2 diabetes, including those with mild to severe renal impairment. This article reviews the clinical efficacy and tolerability of add-on saxagliptin therapy in patients with type 2 diabetes, in line with its approved indications in the EU, and summarizes the drug's pharmacological properties. The clinical efficacy of saxagliptin 5 mg/day in combination with metformin, glibenclamide (glyburide), a thiazolidinedione, or insulin (with or without metformin) has been demonstrated in several randomized, double-blind, placebo-controlled, multicentre, phase III trials (18-104 weeks in duration) in patients with type 2 diabetes. In these trials, glycosylated haemoglobin (HbA(1c)) was changed from baseline (primary endpoint) by a greater extent with add-on saxagliptin 5 mg/day (-1.09% to +0.03%) than with comparator regimens (-0.44% to +0.69%). Two other randomized, double-blind trials showed that saxagliptin 5 mg/day as add-on therapy to metformin was noninferior to uptitrated glipizide in terms of lowering HbA(1c) (-0.74% vs -0.80%) at 52 weeks, or sitagliptin (-0.52% vs -0.62%) at 18 weeks. Saxagliptin 2.5 mg/day as add-on to existing anti-diabetic therapy was also effective for up to 52 weeks in a randomized, double-blind, placebo-controlled, multicentre trial in patients with type 2 diabetes and renal impairment (HbA(1c) was reduced by 1.08% vs 0.36%; p ≤ 0.007). Saxagliptin as add-on therapy for up to 4 years was generally well tolerated in clinical trials. Treatment with saxagliptin did not increase the risk of hypoglycaemia or cardiovascular outcomes relative to placebo or active comparators, and was generally weight neutral. In conclusion, saxagliptin is a useful option as add-on therapy to metformin, a sulfonylurea, a thiazolidinedione, or insulin (with or without metformin) in patients with type 2 diabetes who require combination therapy.

A review of gliptins in 2011

INTRODUCTION

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

AREAS COVERED

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

EXPERT OPINION

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

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

INTRODUCTION

Increasing population age, obesity and physical inactivity mean that type 2 diabetes mellitus (T2DM) is increasingly common. Current treatments may be limited by adverse events, drug-drug interactions or contraindication/need for dose adjustment in patients with renal impairment.

AREAS COVERED

This paper reviews studies that evaluate the pharmacokinetics, pharmacodynamics and clinical efficacy and safety of linagliptin , a dipeptidyl peptidase-4 (DPP-4) inhibitor, recently approved in the US, Japan and Europe for the treatment of T2DM.

EXPERT OPINION

Oral linagliptin, 5 mg once daily, is an effective, well-tolerated DPP-4 inhibitor, suitable for use in a wide range of patients with T2DM. It is weight-neutral, without increasing the risk of hypoglycemia, and can be administered either alone or in combination with other diabetes treatments. It has a unique pharmacological profile within its class and, unlike other DPP-4 inhibitors, linagliptin does not require dose adjustment in patients with renal impairment.

Saxagliptin plus metformin combination therapy

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

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.

DPP-4 inhibitors in the management of type 2 diabetes: a critical review of head-to-head trials

Dipeptidyl peptidase-4 (DPP-4) inhibitors offer new options for the management of type 2 diabetes. Direct comparisons with active glucose-lowering comparators in drug-naive patients have demonstrated that DPP-4 inhibitors exert slightly less pronounced HbA(1c) reduction than metformin (with the advantage of better gastrointestinal tolerability) and similar glucose-lowering effects as with a thiazolidinedione (TZD; with the advantage of no weight gain). In metformin-treated patients, gliptins were associated with similar HbA(1c) reductions compared with a sulphonylurea (SU; with the advantage of no weight gain, considerably fewer hypoglycaemic episodes and no need for titration) and a TZD (with the advantage of no weight gain and better overall tolerability). DPP-4 inhibitors also exert clinically relevant glucose-lowering effects compared with a placebo in patients treated with SU or TZD (of potential interest when metformin is either not tolerated or contraindicated), and as oral triple therapy with a good tolerability profile when added to a metformin-SU or pioglitazone-SU combination. Several clinical trials also showed a consistent reduction in HbA(1c) when DPP-4 inhibitors were added to basal insulin therapy, with no increased risk of hypoglycaemia. Because of the complex pathophysiology of type 2 diabetes and the complementary actions of glucose-lowering agents, initial combination of a DPP-4 inhibitor with either metformin or a glitazone may be applied in drug-naive patients, resulting in greater efficacy and similar safety compared with either drug as monotherapy. However, DPP-4 inhibitors were less effective than GLP-1 receptor agonists for reducing HbA(1c) and body weight, but offer the advantage of being easier to use (oral instead of injected administration) and lower in cost. Only one head-to-head trial demonstrated the non-inferiority of saxagliptin vs sitagliptin. Clearly, more trials of direct comparisons between different incretin-based therapies are needed. Because of their pharmacokinetic characteristics, pharmacodynamic properties (glucose-dependent glucose-lowering effect) and good overall tolerability profile, DPP-4 inhibitors may have a key role to play in patients with renal impairment and in the elderly. The role of DPP-4 inhibitors in the therapeutic armamentarium of type 2 diabetes is rapidly evolving as their potential strengths and weaknesses become better defined mainly through controlled clinical trials.

[Incretin-based therapy for treating patients with type 2 diabetes]

In the last couple of years, a new class of antidiabetic drugs became available for the clinical practice. Due to the intensive research, several new drugs reached the market. Among the incretinmimetics both the GLP-1 (glucagon like peptide-1)-receptor agonist exenatide and the GLP-1-analogue liraglutide can be used for treatment. As for incretin enhancers (dipeptidyl-peptidase-4 [DPP-4]-inhibitors), sitagliptin, vildagliptin and saxagliptin are available in Hungary, linagliptin will be introduced to the market in the near future. In clinical practice, any incretin-based new drugs can be used for treating patients with type 2 diabetes, preferably in combination with metformin. The clinical experiences with these new drugs are reviewed focusing on both the benefits and the potential side-effects of the particular compounds.