Saxagliptin given in combination with metformin as initial therapy improves glycaemic control in patients with type 2 diabetes compared with either monotherapy: a randomized controlled trial

PROGRESSING CHRONIC KIDNEY DISEASE AND THE 12-MONTH DYNAMICS OF CARDIOVASCULAR RISK FACTORS IN PATIENTS WITH ARTERIAL HYPERTENSION AND TYPE 2 DIABETES MELLITUS

Aim. To assess the association between the 12-month dynamics of cardiovascular risk factors (CVD RFs), progressing chronic kidney disease (CKD), and individual baseline clinical and laboratory parameters in patients with arterial hypertension (AH) and Type 2 diabetes mellitus (DM-2) who received active antidiabetic treatment.

Material and methods. In total, 122 patients with AH and DM-2 underwent the laboratory assessment of blood and urine samples at baseline and 12 months later, in order to evaluate the levels and dynamics of CVD RFs and CKD severity.

Results. After 12 months of continuous therapy with antihypertensive and oral antidiabetic medications and statins, the carbohydrate metabolism parameters significantly improved. However, creatinine clearance decreased significantly (by 7,52%). The direction of renal function parameter changes was determined by the baseline CKD stage. Progressing CKD was also associated with obesity (O), atrial fibrillation (AF), and myocardial infarction (MI) in medical history. In patients with or without O, the albumin-creatinine ratio decreased by 59,8% and 34%, respectively. In participants with or without AF, microalbuminuria increased by 321% and decreased by 53,5%, respectively. In patients with MI in medical history, urine levels of creatinine decreased by 33,6%, while in the other patients, they increased by 5,4%. O was associated with a reduction in total cholesterol (TCH) by 5,5%, while in non-obese patients, TCH levels did not change substantially.

Conclusion. In most patients with AH and DM-2, adequate glycemia control, standard antihypertensive treatment, and statin therapy for 12 months were associated with minimal changes in CVD RFs and with a significant deterioration in renal function. The latter was predicted by the CKD stage at baseline, O, MI in medical history, and AF. 

The cardiovascular safety of incretin-based therapies: a review of the evidence

Cardiovascular disease (CVD) is a leading cause of morbidity and mortality in people with diabetes and therefore managing cardiovascular (CV) risk is a critical component of diabetes care. As incretin-based therapies are effective recent additions to the glucose-lowering treatment armamentarium for type 2 diabetes mellitus (T2D), understanding their CV safety profiles is of great importance. Glucagon-like peptide-1 (GLP-1) receptor agonists have been associated with beneficial effects on CV risk factors, including weight, blood pressure and lipid profiles. Encouragingly, mechanistic studies in preclinical models and in patients with acute coronary syndrome suggest a potential cardioprotective effect of native GLP-1 or GLP-1 receptor agonists following ischaemia. Moreover, meta-analyses of phase 3 development programme data indicate no increased risk of major adverse cardiovascular events (MACE) with incretin-based therapies. Large randomized controlled trials designed to evaluate long-term CV outcomes with incretin-based therapies in individuals with T2D are now in progress, with the first two reporting as this article went to press.

Saxagliptin efficacy and safety in patients with type 2 diabetes mellitus and cardiovascular disease history or cardiovascular risk factors: results of a pooled analysis of phase 3 clinical trials

OBJECTIVE

This post hoc analysis sought to assess the efficacy, safety, and tolerability of saxagliptin in patients with type 2 diabetes mellitus and cardiovascular (CV) risk factors or disease (CVD).

METHODS

Data from 5 randomized controlled trials were pooled to compare saxagliptin 5 mg with placebo: 2 studies of saxagliptin as monotherapy in drug-naïve patients and 1 each of saxagliptin as add-on therapy to metformin, glyburide, or a thiazolidinedione. Analysis was performed according to the following baseline/trial entry criteria: 1) history/no history of CVD; 2) ≥ 2 versus 0 to 1 CV risk factors; 3) statin use versus no statin use; and 4) hypertension versus no hypertension. Change from baseline glycated hemoglobin (HbA1c), fasting plasma glucose, and postprandial glucose levels; and the proportion of patients achieving an HbA1c level < 7% were analyzed (week 24). Safety was assessed by adverse events, hypoglycemia, and body weight.

RESULTS

In total, 882 patients received saxagliptin 5 mg and 799 received placebo. Differences in adjusted mean change from baseline HbA1c (95% CI) were greater with saxagliptin compared with placebo in patients with a history of CVD (-0.64% [-0.90 to -0.38]) and no history of CVD (-0.68% [-0.78 to -0.58]); with ≥ 2 CV risk factors (-0.73% [-0.85 to -0.60]) and 0 to 1 CV risk factor (-0.62% [-0.75 to -0.48]); with statin use (-0.70% [-0.89 to -0.52]) and no statin use (-0.66% [-0.77 to -0.56]); and with hypertension (-0.69% [-0.82 to -0.57]) and no hypertension (-0.66% [-0.80 to -0.52]). Saxagliptin was well tolerated, with similar adverse event rates and types compared with placebo. There was a < 1% rate of confirmed hypoglycemia in all groups except in patients with CV history who received placebo (2.1%).

CONCLUSION

Saxagliptin improved glycemic measures, resulted in low rates of confirmed hypoglycemia, and was well tolerated in patients with or without CVD and CV risk factors.

Clinically relevant reductions in HbA1c without hypoglycaemia: results across four studies of saxagliptin

BACKGROUND

In four 24-week controlled studies, the antihyperglycaemic efficacy of saxagliptin was demonstrated in patients with type 2 diabetes mellitus as add-on therapy to glyburide, a thiazolidinedione, or metformin, and when used in initial combination with metformin vs. metformin monotherapy in drug-naive patients.

METHODS

Data from these studies were analysed to compare the proportions of patients who achieved specific reductions from baseline in glycated haemoglobin [HbA(1c); reductions of ≥ 0.5% and ≥ 0.7% in all studies (prespecified); reductions ≥ 1.0% in the add-on studies and ≥ 1.0% to ≥ 2.5% in the initial combination study (post hoc)] for saxagliptin vs. comparator at week 24. We report overall rates of glycaemic response defined by these reductions in HbA(1c) and rates of response without experiencing hypoglycaemia.

RESULTS

Large glycaemic response rates were higher with saxagliptin 2.5 and 5 mg/day than with comparator (HbA(1c) ≥ 1.0%, 31.7-50.3% vs. 10.3-20.0%) as add-on therapy and higher with saxagliptin 5 mg/day as initial combination with metformin than with metformin monotherapy (HbA(1c) ≥ 2.0%, 68.3% vs. 49.8%) in drug-naive patients. Addition of saxagliptin was associated with a low incidence of hypoglycaemia; overall response rates and response rates excluding patients who experienced hypoglycaemia were similar. Analysis of several demographic and baseline clinical variables revealed no consistent correlations with response to saxagliptin.

CONCLUSIONS

Whether receiving saxagliptin as an add-on therapy to glyburide, a thiazolidinedione, or metformin or in initial combination with metformin, a greater percentage of patients achieve clinically relevant large reductions in HbA(1c) vs. comparator, with a low incidence of hypoglycaemia.

Tolerability and efficacy of glycemic control with saxagliptin in older patients (aged ≥ 65 years) with inadequately controlled type 2 diabetes mellitus

Purpose

To assess safety and efficacy of saxagliptin in older patients with type 2 diabetes mellitus (T2DM).

Patients and methods

This was a post hoc analysis of pooled data from older patients (≥65 years of age) from five 24-week phase III trials: three studies of saxagliptin versus placebo as an add-on therapy to metformin, glyburide, or a thiazolidinedione; and two studies of saxagliptin versus placebo as monotherapy in drug-naïve patients. Separate analyses were conducted on one study of initial combination therapy with saxagliptin plus metformin versus metformin monotherapy in drug-naïve patients. The safety analysis population for the five-study pool included 428 patients ≥ 65 years of age with baseline glycated hemoglobin (HbA_1c) 7.0% to 10.5% who received saxagliptin 2.5 or 5 mg or placebo, and for the study of initial combination therapy included 69 patients ≥ 65 years of age with baseline HbA_1c 8.0% to 12.0% who received saxagliptin 5 mg in combination with metformin or metformin monotherapy. The primary efficacy endpoint was change from baseline HbA_1c.

Results

In the five-study pool, the differences in the adjusted mean change from baseline HbA_1c among older patients receiving saxagliptin versus placebo were −0.60% (95% confidence interval [CI], −0.99% to −0.21%) for saxagliptin 2.5 mg and −0.55% (−0.97% to −0.14%) for saxagliptin 5 mg; in the initial combination study, the difference was −1.22% (−2.27% to −0.17%) among older patients receiving saxagliptin 5 mg plus metformin versus metformin monotherapy. The results were generally similar in older and younger patients. Saxagliptin was well tolerated; the incidence and types of adverse events were similar for saxagliptin and comparators. Hypoglycemia was reported in 3.0% to 9.4% of patients receiving saxagliptin (0%–8.0% for comparators) and was confirmed (finger stick glucose ≤ 50 mg/dL, with associated symptoms) in 0% to 0.7% (0%–0.7% for comparators); hypoglycemic episodes did not vary by age category and did not require medical intervention.

Conclusion

Saxagliptin was effective and well tolerated, with a low risk of hypoglycemia, when used as monotherapy, add-on therapy, or initial combination therapy with metformin in older patients with T2DM.

Evaluating Second-Line Treatment Options for Type 2 Diabetes: Focus on Secondary Effects of GLP-1 Agonists and DPP-4 Inhibitors

OBJECTIVE

To discuss the controversy surrounding selection of second-line type 2 diabetes mellitus (T2DM) therapy by reviewing available data regarding secondary effects of glucagon-like peptide-1 receptor (GLP-1) agonists and dipeptidyl peptidase-4 (DPP-4) inhibitors, which include low hypoglycemia risk, weight loss, and cardiovascular (CV) and β-cell function benefits.

DATA SOURCES

A MEDLINE search (1966–March 2013) was conducted using the following key terms: β-cell protection, blood pressure, DPP-4 inhibitors, exena tide, exenatide extended-release, GLP-1 agonists, hypoglycemia, lina glip tin, lipid, liraglutide, pancreatitis, saxagliptin, sitagliptin, and type 2 diabetes.

STUDY SELECTION AND DATA EXTRACTION

Identified articles published in English were evaluated for inclusion, with priority given to randomized controlled trials in humans receiving incretin monotherapy or incretin combination therapy with metformin. References identified in these articles were reviewed for additional trials.

DATA SYNTHESIS

Most patients with T2DM use combination therapy; however, determination of the second-line agent that is most appropriate is debatable. Prior to the use of incretin therapies, traditional second-line agents included sulfonylureas, thiazolidinediones, and basal insulin, all of which demonstrate undesirable adverse effects. In addition to improving glycemic control, incretin therapies have demonstrated benefits concerning hypoglycemic risk and weight loss in addition to potential improvements in CV risk factors and β-cell function. While there are risks associated with using incretins, most patients with T2DM are good candidates for incretins and could benefit from their potential secondary effects. Cost remains a barrier to initiating these agents.

CONCLUSIONS

Demonstrated secondary benefits in addition to efficacy may make GLP-1 agonists and DPP-4 inhibitors a more favorable option than other second-line T2DM therapies.

Differences in the glucose-lowering efficacy of dipeptidyl peptidase-4 inhibitors between Asians and non-Asians: a systematic review and meta-analysis

AIMS/HYPOTHESIS

The aim of this work was to compare the glucose-lowering efficacy of dipeptidyl peptidase-4 (DPP-4) inhibitors between Asian and non-Asian patients with type 2 diabetes.

METHODS

We searched MEDLINE, EMBASE, LILACS, CENTRAL, ClinicalTrials.gov and conference proceedings. Studies were eligible if they were randomised controlled trials with a treatment duration of at least 12 weeks, compared a DPP-4 inhibitor with a placebo as either monotherapy or oral combination therapy, had information on ethnicity and HbA1c values and were published or described in English. A systematic review and meta-analysis with a meta-regression analysis was conducted.

RESULTS

Among 809 potentially relevant studies, 55 trials were included. A meta-analysis revealed that DPP-4 inhibitors lowered HbA1c to a greater extent in studies with ≥50% Asian participants (weighted mean difference [WMD] -0.92%; 95% CI -1.03, -0.82) than in studies with <50% Asian participants (WMD -0.65%; 95% CI -0.69, -0.60). The between-group difference was -0.26% (95% CI -0.36, -0.17, p < 0.001). The baseline BMI significantly correlated with the HbA1c-lowering efficacy of DPP-4 inhibitors. The RR of achieving the goal of HbA1c <7.0% (53.0 mmol/mol) was higher in studies with ≥50% Asian participants (3.4 [95% CI 2.6, 4.7] vs 1.9 [95% CI 1.8, 2.0]). The fasting plasma glucose-lowering efficacy was higher with monotherapy in the Asian-dominant studies, but the postprandial glucose-lowering efficacy and changes in body weight were comparable between the two groups.

CONCLUSIONS/INTERPRETATION

DPP-4 inhibitors exhibit a better glucose-lowering efficacy in Asians than in other ethnic groups; this requires further investigation to understand the underlying mechanism, particularly in relation to BMI.

Combine and conquer: advantages and disadvantages of fixed-dose combination therapy

The majority of patients with type 2 diabetes mellitus (T2DM) do not achieve the glycaemic goals recommended by leading diabetes organizations using monotherapy alone, and often require multiple antihyperglycaemic agents to achieve glycaemic control. Fixed-dose combination (FDC) therapies offer a means to simplify complex treatment regimens, and have several advantages that help patients reach their glycaemic goals. In this review, four key benefits are identified and discussed in support of FDCs for treatment of patients with T2DM: (i) Greater efficacy compared with higher dose monotherapy, (ii) Reduced risk of adverse reactions relative to higher dose monotherapy, (iii) Lower overall costs and (iv) Improved medication concordance. Given these advantages, the place of fixed combination therapy in the course of treatment is discussed. Establishing a therapeutic strategy that incorporates fixed combination therapy (including combinations with insulin) will simplify the treatment of diabetes, ideally resulting in improved medication concordance, clinical outcomes and quality of life for patients with T2DM.

Saxagliptin vs. glipizide as add-on therapy in patients with type 2 diabetes mellitus inadequately controlled on metformin alone: long-term (52-week) extension of a 52-week randomised controlled trial

AIM

To compare the long-term safety, tolerability and efficacy of saxagliptin vs. glipizide as add-on therapy to metformin.

METHODS

Adults with glycated haemoglobin (HbA1c) > 6.5-10% (on stable metformin ≥ 1500 mg/day) were randomised to saxagliptin 5 mg/day (n = 428) or glipizide titrated from 5 to 20 mg/day (mean dose 15 mg/day; n = 430) for 52 weeks with a 52-week extension (NCT00575588). Assessment of the long-term safety, tolerability and efficacy of add-on saxagliptin vs. glipizide after 104 weeks was a tertiary objective of the initial 52-week study.

RESULTS

Saxagliptin was well tolerated during the 104-week period; 67.1% of patients receiving saxagliptin vs. 72.6% receiving glipizide had ≥ 1 adverse event (AE), and few patients (4.9% vs. 5.6%) discontinued owing to AEs. Fewer patients treated with saxagliptin experienced hypoglycaemia (3.5% vs. 38.4% with glipizide; difference, -34.9%, 95% CI, -39.8 to -30.0) or confirmed hypoglycaemia (0 vs. 9.1% with glipizide). Weight loss was observed with saxagliptin (-1.5 kg) vs. weight gain with glipizide (+1.3 kg; between-group difference, -2.8 kg, 95% CI, -3.32 kg to -2.20 kg). Change from baseline in HbA1c was -0.41 ± 0.04% with saxagliptin and -0.35 ± 0.04% with glipizide (between-group difference, -0.05%, 95% CI, -0.17 to 0.06%). A post hoc analysis showed that the proportion of patients with baseline HbA1c ≥ 7% who achieved HbA1c < 7% (observed data) at week 104 was 23.1% for saxagliptin + metformin and 22.7% for glipizide + metformin.

DISCUSSION AND CONCLUSION

A lower risk of hypoglycaemia and reduced body weight were observed with saxagliptin vs. glipizide. No other clinically significant differences were observed between groups in safety profile. No significant between-group differences were observed for reductions in glycaemic parameters. After week 24, a smaller weekly rise in HbA1c was observed with saxagliptin vs. glipizide as add-on therapy to metformin.

An emerging role of dipeptidyl peptidase 4 (DPP4) beyond glucose control: potential implications in cardiovascular disease

The introduction of dipeptidyl peptidase 4 (DPP4) inhibitors for the treatment of Type 2 diabetes acknowledges the fundamental importance of incretin hormones in the regulation of glycemia. Small molecule inhibitors of DPP4 exert their effects via inhibition of enzymatic degradation of glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic peptide (GIP). The widespread expression of DPP4 in tissues such as the vasculature and immune cells suggests that this protein may play a role in cardiovascular function. DPP4 is known to exert its effects via both enzymatic and non-enzymatic mechanisms. A soluble form of DPP4 lacking the cytoplasmic and transmembrane domain has also been recently recognized. Besides enzymatic inactivation of incretins, DPP4 also mediates degradation of many chemokines and neuropeptides. The non-enzymatic function of DPP4 plays a critical role in providing co-stimulatory signals to T cells via adenosine deaminase (ADA). DPP4 may also regulate inflammatory responses in innate immune cells such as monocytes and dendritic cells. The multiplicity of functions and targets suggests that DPP4 may play a distinct role aside from its effects on the incretin axis. Indeed recent studies in experimental models of atherosclerosis provide evidence for a robust effect for these drugs in attenuating inflammation and plaque development. Several prospective randomized controlled clinical trials in humans with established atherosclerosis are testing the effects of DPP4 inhibition on hard cardiovascular events.

Saxagliptin and Metformin in Fixed Combination for the Treatment of Type 2 Diabetes in Adults

Type 2 diabetes affects millions of people worldwide and significantly contributes to morbidity and mortality of those affected by it. Current guidelines recommend individualized treatment regimens following first line metformin therapy. Saxagliptin, a dipeptidyl-peptidase 4 inhibitor, provides a secondary mechanism of action to decrease hyperglycemia when used in combination with metformin. The combination of metformin and saxagliptin has shown improvements in hemoglobin A_1c and fasting plasma glucose in greater efficacy than when either agent is used alone. Adverse effects of combination therapy are similar to when these agents are used individually, and are rated as tolerable by patient satisfaction scores. Overall, the combination use of saxagliptin in addition to metformin is an attractive option for clinicians to use in the treatment of type 2 diabetes.

Initial combination with linagliptin and metformin in newly diagnosed type 2 diabetes and severe hyperglycemia

Making appropriate treatment decisions for patients newly diagnosed with type 2 diabetes mellitus (T2DM) and severe hyperglycemia (glycated hemoglobin [HbA1c]>10% or fasting plasma glucose≥250 mg/dL) presents a formidable challenge to primary care physicians. Extreme defects in insulin secretion make it unlikely that these patients will achieve glycemic targets with metformin monotherapy. Additionally, uncontrolled hyperglycemia is associated with an increased risk of short-term acute complications, such as hyperosmolar coma, and long-term complications affecting the micro- and macrovasculature. Thus, severely hyperglycemic patients require prompt, intensive treatment to re-establish glycemic control. Current guidelines indicate that either initial insulin therapy or initial combination therapy with metformin plus non-insulin drug(s) are the treatments of choice for these challenging-to-treat patients. This mini-review examines the clinical evidence supporting these two treatment options, with particular reference to the findings of a phase 3 study of treatment with an initial combination of metformin plus the dipeptidyl peptidase-4 inhibitor, linagliptin. Intensive insulin therapy can induce sustained euglycemia and improve beta-cell function in newly diagnosed patients. However, insulin use is associated with an increased risk of adverse events, such as hypoglycemia and weight gain. These potentially serious side effects cause concern among patients and physicians, and are a major barrier to initiating and maintaining adherence to insulin treatment. In the phase 3 study, open-label treatment of severely hyperglycemic patients (HbA1c≥11.0%) with linagliptin plus metformin resulted in a mean change in HbA1c of -3.7%±1.7%. This combination therapy was generally well tolerated with most adverse events being of mild or moderate intensity; asymptomatic hypoglycemia was reported by just 1 of 66 (1.5%) patients. These findings provide evidence in support of linagliptin plus metformin as a well-tolerated and effective treatment alternative to insulin for new-onset patients with T2DM and severe hyperglycemia.

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.

Effects of saxagliptin added to sub-maximal doses of metformin compared with uptitration of metformin in type 2 diabetes: the PROMPT study

OBJECTIVE

The PROMPT study compared efficacy and tolerability of two treatment intensification strategies: adding saxagliptin or uptitrating metformin monotherapy, in patients with type 2 diabetes (T2D) and inadequate glycaemic control on a sub-maximal metformin dose.

RESEARCH DESIGN AND METHODS

In this double-blind, 24-week study, metformin-tolerant patients with T2D on metformin monotherapy were randomised to receive fixed-dose metformin 1500 mg/day, plus either add-on saxagliptin 5 mg/day (SAXA-MET) or a two-step metformin uptitration (MET-UP) to a maximum dose (2500 mg/day).

CLINICAL TRIAL REGISTRATION

NCT01006590.

MAIN OUTCOME MEASURES

Primary: absolute change from baseline in glycated haemoglobin A(1c) (HbA(1c)) (Week 24). Secondary: proportion of patients achieving a therapeutic glycaemic response (Week 24); change from baseline in fasting plasma glucose (Week 24); safety and tolerability. Exploratory analyses comprised three patient-related questionnaires, including the validated 5-dimension Digestive Health Status Index (DHSI).

RESULTS

A total of 286 patients were randomised: (SAXA-MET: 147; MET-UP: 139). Baseline mean (SD) HbA(1c): 7.71 (0.85; SAXA-MET); 7.80 (0.82; MET-UP). Adjusted mean reductions from baseline in HbA(1c) (Week 24): -0.47% (SAXA-MET); -0.38% (MET-UP); mean (95% CI) difference in treatment effect, -0.10% (-0.26, 0.07); p = 0.260. The proportion of patients (95% CI) achieving a therapeutic glycaemic response (HbA(1c) < 7%): 43.8% (34.8, 49.6) (SAXA-MET) vs. 35.0% (29.0, 43.8) (MET-UP). Of the five DHSI domains, mean (95% CI) differences were observed for diarrhoea-predominant score (+0.8 [-2.5, 4.0] vs. +7.9 [4.6, 11.2]) and dysmotility score (-0.5 [-2.0, 1.0] vs. +1.9 [0.3, 3.4]), (SAXA-MET and MET-UP, respectively). The most common adverse event was diarrhoea: 6.1% (SAXA-MET) vs. 12.2% (MET-UP).

CONCLUSIONS

In metformin-tolerant patients with T2D (inadequately controlled on sub-maximal metformin monotherapy), saxagliptin was well tolerated. Although HbA(1c) reduction was not significantly different between treatment groups, the lower occurrence of gastrointestinal symptoms in the SAXA-MET group suggests that saxagliptin add-on treatment may be a suitable alternative treatment strategy to metformin uptitration.

Patient-reported outcomes in trials of incretin-based therapies in patients with type 2 diabetes mellitus

Incretin-based therapies have a glucose-dependent mode of action that results in excellent glucose-lowering efficacy with very low risk of hypoglycaemia, and weight neutrality [dipeptidyl peptidase-4 (DPP-4) inhibitors] or weight loss [glucagon-like peptide-1 (GLP-1) receptor agonists], in people with type 2 diabetes mellitus (T2DM). Patient-reported outcomes (PROs) complement physician evaluations of efficacy and tolerability and offer insights into the subjective experience of using modern diabetes treatments. We conducted a systematic search of clinical trials of the GLP-1 receptor agonists liraglutide, exenatide and long-acting exenatide, one of which included the oral DPP-4 inhibitor sitagliptin as a comparator. No other PRO data for DPP-4 inhibitors were identified. This review summarizes PRO data from eight clinical trials, the majority of which used the Diabetes Treatment Satisfaction Questionnaire (DTSQ) and/or Impact of Weight on Quality of Life-Lite (IWQOL-Lite) to evaluate patient experience. People with T2DM were highly satisfied with modern incretin-based therapies compared with traditional therapies. Treatment satisfaction (including perceptions of convenience and flexibility) was high and generally higher with GLP-1 agonists in association with their greater glucose-lowering efficacy and tendency to facilitate weight loss. Weight-related quality of life (QoL) also improved in people using incretin therapies. The glycaemic improvements achieved with GLP-1 receptor agonists, coupled with the low incidence of hypoglycaemia and ability to cause weight loss, seemed to offset potential concern about injections. It is plausible that superior patient-reported benefits found in clinical trials may translate into improved, clinically meaningful, long-term outcomes through increased treatment acceptability. Long-term, prospective data are needed to ascertain whether this is the case in practice.

Incretin-based therapy in combination with basal insulin: a promising tactic for the treatment of type 2 diabetes

Incretin therapies such as dipeptidyl peptidase-4 inhibitors (DPP-4Is) and GLP-1 receptor agonists (GLP-1RAs) have become well-established treatments for type 2 diabetes. Both drug classes reduce blood glucose through physiological pathways mediated by the GLP-1 receptor, resulting in glucose-dependent enhancement of residual insulin secretion and inhibition of glucagon secretion. In addition, the GLP-1RAs reduce gastrointestinal motility and appear to have appetite-suppressing actions and, so, are often able to produce clinically useful weight loss. The glucose-dependency of their glucagon-inhibiting and insulin-enhancing effects, together with their weight-sparing properties, make the incretin therapies a logical proposition for use in combination with exogenous basal insulin therapy. This combination offers the prospect of an additive or synergistic glucose-lowering effect without a greatly elevated risk of hypoglycaemia compared with insulin monotherapy, and any insulin-associated weight gain might also be mitigated. Furthermore, the incretin therapies can be combined with metformin, which is usually continued when basal insulin is introduced in type 2 diabetes. Although the combination of incretin and insulin therapy is currently not addressed in internationally recognized treatment guidelines, several clinical studies have assessed its use. The data, summarized in this review, are encouraging and show that glycaemic control is improved and weight gain is limited or reversed (especially with the combined use of GLP-1RAs and basal insulin), and that the use of an incretin therapy can also greatly reduce insulin dose requirements. The addition of basal insulin to established incretin therapy is straightforward, but insulin dose adjustment (though not discontinuation) is usually necessary if the sequence is reversed.

Effects on lipid profile of dipeptidyl peptidase 4 inhibitors, pioglitazone, acarbose, and sulfonylureas: meta-analysis of placebo-controlled trials

INTRODUCTION

Lipid profile is an important determinant of cardiovascular risk in type 2 diabetes. It is well known that patients with type 2 diabetes are more likely to be dyslipidemic than the general population. Given the observed connection between glucose and lipid metabolism in patients with type 2 diabetes, it is conceivable that different glucose-lowering agents can have a varying impact on the lipid profile. When metformin monotherapy fails, other drugs can be added to achieve sufficient glycemic control. Available oral agents include pioglitazone, acarbose, dipeptidyl peptidase 4 (DPP-4) inhibitors, and insulin secretagogs. The present meta-analysis was designed to assess the effect of DPP-4 inhibitors, pioglitazone, insulin secretagogs, and acarbose on blood lipids when compared to placebo.

METHODS

An extensive search (any date up to November 1, 2011) was performed for all trials performed on the following classes of drugs: gliptin, insulin secretagogs, pioglitazone, and acarbose. The following endpoints were considered: endpoint total, high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C) and triglycerides.

RESULTS

The difference in mean total cholesterol values at endpoint versus baseline was significantly higher in patients on pioglitazone, sulfonylureas, and DPP-4 inhibitor treatment (but not on acarbose) than those on placebo, demonstrating that treatment with these drugs (except acarbose) is associated with a significant reduction in total cholesterol. With respect to triglycerides, a significant reduction could be observed with acarbose, pioglitazone, and DPP-4 inhibitors, but not with sulfonylureas. HDL-C appeared to be increased by treatment with acarbose and pioglitazone, and decreased by sulfonylureas.

CONCLUSION

The present meta-analysis shows that available glucose-lowering drugs may have varying effects on the lipid profile. DPP-4 inhibitors, acarbose, and pioglitazone seem to have a more favorable effect on the lipid profile than sulfonylureas.

The efficacy and safety of the dipeptidyl peptidase-4 inhibitor saxagliptin in treatment-naïve patients with type 2 diabetes mellitus: a randomized controlled trial

BACKGROUND

The aim of this study was to assess efficacy and safety of saxagliptin monotherapy for up to 76 weeks in patients with type 2 diabetes mellitus (T2DM) and inadequate glycemic control, with main efficacy assessment at 24 weeks.

METHODS

365 treatment-naïve patients with T2DM (HbA1c 7.0%-10.0%) were treated with saxagliptin 2.5 mg q.A.M., saxagliptin 2.5 mg q.A.M. with possible titration to saxagliptin 5 mg, saxagliptin 5 mg q.A.M., saxagliptin 5 mg q.P.M., or placebo. After week 24, patients in all groups were eligible for titration to saxagliptin 10 mg based on HbA1c ≥7%, and all unrescued placebo patients began blinded metformin 500 mg/day. Rescue with open-label metformin was available for patients with inadequate glycemic control.

RESULTS

At week 24, placebo-subtracted mean HbA1c reduction from baseline (LOCF) was significantly greater in the saxagliptin treatment groups vs placebo, and remained greater through week 76. Serious adverse events (AEs) and discontinuations due to AEs were similar in saxagliptin and control groups; incidence of confirmed hypoglycemia was low across all treatment groups (saxagliptin-treated, 2 [0.7]; control, 1 [1.4]).

CONCLUSIONS

In treatment-naïve patients with T2DM, saxagliptin monotherapy demonstrated statistically significant improvement in HbA1c compared with placebo at 24 weeks and was generally well tolerated for up to 76 weeks.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT00316082.

Safety of saxagliptin: rationale for and design of a series of postmarketing observational studies

PURPOSE

To describe the design and rationale of a series of postmarketing studies to examine the safety of saxagliptin, an oral dipeptidyl peptidase-4 inhibitor for the treatment of type 2 diabetes mellitus, in real-world settings.

METHODS

We are conducting a series of retrospective cohort studies using two UK (General Practice Research Database, and The Health Improvement Network) and two US (Medicare, HealthCore Integrated Research Database(SM) ) data sources. The primary outcomes of interest will include (i) hospitalization with acute liver failure, (ii) hospitalization for acute kidney injury, (iii) hospitalization for severe hypersensitivity reactions, (iv) hospitalization for severe infections, (v) hospitalization with infections associated with T-lymphocyte dysfunction (i.e., herpes zoster, tuberculosis, or nontuberculous mycobacteria), and (vi) major cardiovascular events. Diagnosis codes for the outcomes of interest will be validated by medical record review within each data source. Projected use and estimated incidence rates of outcomes of interest suggest there will be at least 80% statistical power to detect a minimum hazard ratio of 1.5 for major cardiovascular events, 2.0 for acute kidney injury and severe infections, 2.4 for acute liver failure, and 4.0 for severe hypersensitivity reactions.

RESULTS

Forthcoming.

CONCLUSIONS

This postmarketing safety assessment will provide important information regarding the safety of saxagliptin and could potentially identify important dipeptidyl peptidase-4 inhibitor class effects. The methods described may be useful to others planning similar evaluations.

Cost effectiveness of saxagliptin and metformin versus sulfonylurea and metformin in the treatment of type 2 diabetes mellitus in Germany: a Cardiff diabetes model analysis

BACKGROUND

The lack of adequate glycaemic control for patients with type 2 diabetes mellitus (T2DM), especially with existing second-line therapies, represents an unmet medical need. Of the newer therapies, the incretin-based medicines, such as saxagliptin, look promising to consolidate second-line pharmacotherapy.

OBJECTIVE

This study evaluates the long-term economic consequences of saxagliptin versus sulfonylurea (glipizide) as second-line therapy when used in combination with metformin after failure of monotherapy treatment with metformin, in patients with T2DM in Germany.

METHODS

A published discrete event simulation model with a fixed-time increment was used to model the effects of different treatment scenarios over a 40-year (life-) time horizon. Disease progression was modelled using evidence from the United Kingdom Prospective Diabetes Study (UKPDS) 68. The treatment sequence matched that of published German guidelines, and efficacy and safety data were derived from published sources. The model assumes that quality-adjusted life-years (QALYs) are affected by complications, hypoglycaemic events and weight change over a lifetime. Costs were specific to the German setting, where sulfonylureas are generic. Costs and effects were discounted annually at 3%. The extended perspective of the national sick funds was adopted, and recommendations from the Institute for Quality and Efficiency in Health Care (IQWiG) were considered.

RESULTS

In the base-case analysis, treatment with saxagliptin plus metformin was associated with a lower incidence of both symptomatic and severe hypoglycaemic events, resulting in an incremental benefit of 0.12 QALYs and an incremental cost-effectiveness ratio (ICER) of €13,931 per QALY gained compared with sulfonylurea plus metformin (year of costing 2009). Modest reductions in all macro- and microvascular complications were seen in those receiving saxagliptin plus metformin compared with sulfonylurea plus metformin. Sensitivity analysis showed that treatment-related weight changes, as a risk factor for complications, represent the most influential driver of cost effectiveness.

CONCLUSION

The study demonstrated improved outcomes with saxagliptin at a cost that would likely be considered acceptable in the German setting. Furthermore, the findings of the sensitivity analysis suggest that the results are robust to various assumptions concerning input variables and modelling assumptions.

Drug-induced hypoglycaemia in type 2 diabetes

INTRODUCTION

Hypoglycaemia is a side effect caused by some therapies for type 2 diabetes, which can cause physical, social and psychological harm. Hypoglycaemia also prevents attainment of treatment goals and satisfactory glycaemic control.

AREAS COVERED

The risk of hypoglycaemia associated with commonly prescribed therapies, including metformin, sulphonylureas, dipeptidyl peptidase-4 enzyme (DPP-4) inhibitors, glucagon-like peptide-1 (GLP-1) agonists and thiazolidinediones, is reviewed in this paper (insulin-induced hypoglycaemia is not included). Other medications that are frequently co-prescribed in type 2 diabetes are also discussed, including anti-hypertensive drugs, antibiotics and fibrates, along with various important patient-related risk factors.

EXPERT OPINION

Hypoglycaemia is a common and potentially dangerous side effect of some medications used for type 2 diabetes. The risk of hypoglycaemia should always be considered when selecting and implementing a therapy, with a focus on the individual. Future research into new therapies should measure the frequency of hypoglycaemia prospectively and accurately. Hypoglycaemia has been shown to be a potentially life-threatening metabolic stress; therefore therapies that effectively manage diabetes without the risk of hypoglycaemia are likely to be favoured in the future.

Dapagliflozin, metformin XR, or both: initial pharmacotherapy for type 2 diabetes, a randomised controlled trial

BACKGROUND

Combining metformin (XR) with dapagliflozin to initiate pharmacotherapy in patients with type 2 diabetes (T2D) and high baseline HbA1c may be advantageous. We conducted two randomised, double-blind, three-arm 24-week trials in treatment-naïve patients to compare dapagliflozin plus metformin, dapagliflozin alone and metformin alone.

METHODS

Eligible patients had baseline HbA1c 7.5-12%. Each trial had three arms: dapagliflozin plus metformin, dapagliflozin monotherapy and metformin monotherapy. Dapagliflozin in combination and as monotherapy was dosed at 5 mg (Study 1) and 10 mg (Study 2). Metformin in combination and as monotherapy was titrated to 2000 mg. The primary endpoint was HbA1c change from baseline; secondary endpoints included change in fasting plasma glucose (FPG) and weight.

RESULTS

In both trials, combination therapy led to significantly greater reductions in HbA1c compared with either monotherapy: -2.05 for dapagliflozin + metformin, -1.19 for dapagliflozin, and -1.35 for metformin (p < 0.0001) (Study 1); -1.98 for dapagliflozin + metformin, -1.45 for dapagliflozin and -1.44 for metformin (p < 0.0001) (Study 2). Combination therapy was statistically superior to monotherapy in reduction of FPG (p < 0.0001 for both studies); combination therapy was more effective than metformin for weight reduction (p < 0.0001). Dapagliflozin 10 mg was non-inferior to metformin in reducing HbA1c (Study 2). Events suggestive of genital infection were reported in 6.7%, 6.9% and 2.0% (Study 1) and 8.5%, 12.8% and 2.4% (Study 2) of patients in combination, dapagliflozin and metformin groups; events suggestive of urinary tract infection were reported in 7.7%, 7.9% and 7.5% (Study 1) and 7.6%, 11.0% and 4.3% (Study 2) of patients in the respective groups. No major hypoglycaemia was reported.

CONCLUSION

In treatment-naïve patients with T2D, dapagliflozin plus metformin was generally well tolerated and effective in reducing HbA1c, FPG and weight. Dapagliflozin-induced glucosuria led to an increase in events suggestive of urinary tract and genital infections.

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.

The design of the liraglutide clinical trial programme

Liraglutide is a once-daily human glucagon-like peptide-1 analogue used in the treatment of type 2 diabetes (T2D). It has been prospectively investigated in a series of multinational, randomised, controlled phase 3 trials (the Liraglutide Effect and Action in Diabetes programme), as well as in an additional direct head-to-head study with sitagliptin. These trials were designed to clarify the use and safety of liraglutide in clinical practice across the treatment continuum of T2D, and consequently involved a large number and diverse range of patients. These studies also included active comparisons against antidiabetic agents including metformin, rosiglitazone, glimepiride, insulin glargine, exenatide and sitagliptin, and therefore have helped to examine clinical differences and similarities between liraglutide and these commonly used agents.

Effect of saxagliptin as add-on therapy in patients with poorly controlled type 2 diabetes on insulin alone or insulin combined with metformin

OBJECTIVE

To evaluate efficacy and safety of saxagliptin as add-on therapy in patients with type 2 diabetes (T2D) with inadequate glycemic control on insulin alone or combined with metformin.

METHODS

Adults (n = 455) with HbA(1c) 7.5-11% on stable insulin therapy (30-150 U/day ± metformin) for at least 8 weeks were stratified by metformin use and randomly assigned 2:1 to receive saxagliptin 5 mg or placebo once daily for 24 weeks. Patients were to maintain stable insulin doses but these could be decreased to reduce risk of hypoglycemia. Patients with hyperglycemia or substantially increased insulin use were rescued with a flexible insulin regimen and remained in the study. Metformin doses were kept stable. The primary efficacy endpoint was change in HbA(1c) from baseline to week 24 (or rescue).

RESULTS

Patients treated with saxagliptin versus placebo had significantly greater reductions in adjusted mean HbA(1c) (difference: -0.41%, p < 0.0001), postprandial glucose (PPG) 180-minute area under the curve (-3829.8 mg·min/dL, p = 0.0011), and 120-minute PPG (-23.0 mg/dL, p = 0.0016) at 24 weeks. Treatment with saxagliptin resulted in similar reductions in HBA(1c) relative to placebo, irrespective of metformin treatment. At 24 weeks, difference in adjusted mean fasting plasma glucose for saxagliptin versus placebo was -4.02 mg/dL (p = 0.3958); 17.3% and 6.7% of patients in the saxagliptin and placebo groups, respectively, achieved HbA(1c) < 7%. Mean change from baseline in body weight at week 24 was 0.39 kg for saxagliptin and 0.18 kg for placebo. Hypoglycemia was reported in 18.4% and 19.9% of patients in the saxagliptin and placebo groups, respectively (confirmed hypoglycemia: 5.3%, 3.3%). Other adverse events reported in at least 5% of patients were urinary tract infection (saxagliptin, placebo: 5.9%, 6.0%), influenza (3.0%, 6.6%), and pain in extremity (1.6%, 6.0%).

CONCLUSIONS

Saxagliptin 5-mg once-daily add-on therapy improves glycemic control in T2D patients on insulin alone or combined with metformin and is generally well-tolerated. NCT00757588.

Adding saxagliptin to extended-release metformin vs. uptitrating metformin dosage

AIM

To investigate whether patients taking metformin for type 2 diabetes mellitus (T2DM) have improved glycaemic control without compromising tolerability by adding an agent with a complementary mechanism of action vs. uptitrating metformin.

METHODS

Adults with T2DM and glycated haemoglobin (HbA1c) between 7.0 and 10.5% receiving metformin extended release (XR) 1500 mg/day for ≥8 weeks were randomized to receive saxagliptin 5 mg added to metformin XR 1500 mg (n = 138) or metformin XR uptitrated to 2000 mg/day (n = 144). Endpoints were change from baseline to week 18 in HbA1c (primary), 120-min postprandial glucose (PPG), fasting plasma glucose (FPG) and the proportion of patients achieving HbA1c <7%.

RESULTS

At week 18, the adjusted mean reduction from baseline HbA1c was -0.88% for saxagliptin + metformin XR and -0.35% for uptitrated metformin XR (difference, -0.52%; p < 0.0001). For 120-min PPG and FPG, differences in adjusted mean change from baseline between saxagliptin + metformin XR and uptitrated metformin XR were -1.3 mmol/l (-23.32 mg/dl) (p = 0.0013) and -0.73 mmol/l (-13.18 mg/dl) (p = 0.0030), respectively. More patients achieved HbA1c <7.0% with saxagliptin + metformin XR than with uptitrated metformin XR (37.2 vs. 26.1%; p = 0.0459). The proportions of patients experiencing any adverse events (AEs) were generally similar between groups; neither group showed any notable difference in hypoglycaemia or gastrointestinal AEs.

CONCLUSION

Adding saxagliptin to metformin XR provided superior glycaemic control compared with uptitrating metformin XR without the emergence of additional safety concerns.

Dipeptidyl peptidase-4 inhibitors: 3 years of experience

According to the latest American Diabetes Association guidelines, lowering glycated hemoglobin (HbA(1c)) to below or around 7% has been shown to reduce microvascular and neuropathic complications of diabetes and, if implemented soon after the diagnosis of diabetes, is associated with long-term reduction in macrovascular disease. Recently a new class of antidiabetes drugs has been developed, dipeptidyl peptidase-4 (DPP-4) inhibitors, which act by inhibiting DPP-4, the enzyme that inactivates glucagon-like peptide-1 (GLP-1). Through the inhibition of DPP-4, DPP-4 inhibitors enhance the effects of GLP-1 and glucose-dependent insulinotropic peptide, increasing glucose-mediated insulin secretion and suppressing glucagon secretion. We conducted a review analyzing clinical efficacy and safety of DPP-4 inhibitors, both alone and in combination with other antidiabetes drugs, including randomized controlled trials about sitagliptin, vildagliptin, saxagliptin, and linagliptin conducted in the latest 15 years. We concluded that, once metformin fails to maintain glycemic control, addition of DPP-4 inhibitors should be the logical choice: they seems to lower HbA(1c) levels by 0.6-0.9 percentage points and to have a comparable effect on HbA(1c) versus the addition of a sulfonylurea or glitazone. They also have positive effects on β-cell function, and they have neutral effects on body weight. Furthermore, DPP-4 inhibitors prevent the risk of hypoglycemia posed by sulfonylureas.

Comparison of liraglutide versus other incretin-related anti-hyperglycaemic agents

The two classes of incretin-related therapies, dipeptidyl peptidase-4 (DPP-4) inhibitors and glucagon-like peptide-1 receptor agonists (GLP-1 RAs), have become important treatment options for patients with type 2 diabetes. Sitagliptin, saxagliptin, vildagliptin and linagliptin, the available DPP-4 inhibitors, are oral medications, whereas the GLP-1 RAs-twice-daily exenatide, once-weekly exenatide and once-daily liraglutide-are administered subcutaneously. By influencing levels of GLP-1 receptor stimulation, these medications lower plasma glucose levels in a glucose-dependent manner with low risk of hypoglycaemia, affecting postprandial plasma glucose more than most other anti-hyperglycaemic medications. Use of GLP-1 RAs has been shown to result in greater glycaemic improvements than DPP-4 inhibitors, probably because of higher levels of GLP-1 receptor activation. GLP-1 RAs can also produce significant weight loss and may reduce blood pressure and have beneficial effects on other cardiovascular risk factors. Although both classes are well tolerated, DPP-4 inhibitors may be associated with infections and headaches, whereas GLP-1 RAs are often associated with gastrointestinal disorders, primarily nausea. Pancreatitis has been reported with both DPP-4 inhibitors and GLP-1 RAs, but a causal relationship between use of incretin-based therapies and pancreatitis has not been established. In clinical trials, liraglutide has shown efficacy and tolerability and resulted in certain significant benefits when compared with exenatide and sitagliptin.

Differentiating among incretin therapies: a multiple-target approach to type 2 diabetes

WHAT IS KNOWN AND OBJECTIVE

Incretin-based glucagon-like peptide-1 receptor agonists (GLP-1 RAs) and dipeptidyl peptidase-4 (DPP-4) inhibitor therapies provide glycaemic control with reduced risks associated with weight gain or hypoglycaemia. Incretin therapies are compared with their mechanisms of action, effects on haemoglobin A(1C) (HbA(1C)), fasting plasma glucose (FPG), post-prandial glucose (PPG), body weight, β-cell function, cardiovascular biomarkers and in their safety profiles to aid clinicians in the selection of individualized pharmacotherapy for patients with type 2 diabetes.

METHODS

Relevant articles for a systematic review were identified through PubMed. Randomized, head-to-head comparison studies among incretin therapies were identified and included in the review. Additionally, randomized, controlled monotherapy and combination therapy studies examining glycaemic and extraglycaemic effects of individual incretin therapies from 2007 to 2011 were reviewed.

RESULTS AND DISCUSSION

Glucagon-like peptide-1 receptor agonists are generally preferred over DPP-4 inhibitors because of their greater effectiveness in reducing HbA(1C) , FPG and PPG excursions, and greater weight loss potentiation. As a monotherapy option, longer-acting GLP-1 RAs, including liraglutide and exenatide once-weekly, may be preferred at higher HbA(1C) because of their more pronounced effects on FPG. At lower/near normal HbA(1C) , a short-acting GLP-1 RA, such as exenatide twice-daily, may be a better choice as its effects are more pronounced with PPG. Ideal patients or patient situations for DPP-4 inhibitors include patients who need minimal reduction in HbA(1C,) elderly patients, patients who are unwilling or unable to take an injectable agent, when GLP-1 RAs are contraindicated or when the patient will not benefit from weight loss. Treatment benefits common to all incretin-based therapies include minimal hypoglycaemia risk, potential preservation of β-cell function and effective targeting of multiple organs underlying type 2 diabetes and of comorbidities commonly associated with type 2 diabetes, such as obesity and hypertension.

WHAT IS NEW AND CONCLUSION

Key differences in mechanisms of action and in glycaemic and extra-glycaemic treatment outcomes exist among incretin therapies, both within the GLP-1 RA class, and between GLP-1 RAs and DPP-4 inhibitors. Clinical judgment acknowledging important differences among incretin therapies and treatment-related patient characteristics will aid in the selection of the appropriate incretin agent for individualized pharmacotherapy.

Saxagliptin for the treatment of type 2 diabetes mellitus: focus on recent studies

Dipeptidyl peptidase-4 (DPP-4) inhibitors are a class of oral antidiabetic drugs that improve glycemic control without causing weight gain or increasing hypoglycemic risk in patients with type 2 diabetes (T2DM). The efficacy and tolerability of saxagliptin, a once-daily DPP-4 inhibitor, administered as monotherapy, as add-on therapy to metformin, a sulfonylurea, or a thiazolidinedione, and as initial combination therapy with metformin, was demonstrated in pivotal 24-week clinical trials. Additional information about the clinical profile of saxagliptin was recently obtained from extension studies, head-to-head clinical trials, and post-hoc analyses. In extension studies, the efficacy and tolerability of add-on saxagliptin and initial saxagliptin-plus-metformin therapy were maintained for up to 102 weeks. Saxagliptin plus metformin was shown to be non-inferior to glipizide plus metformin in lowering glycated hemoglobin from base-line, with reduced body-weight and lower hypoglycemic risk. Post-hoc analyses indicate that the clinical benefits of saxagliptin extend across demographic subgroups and special populations. A meta-analysis found no evidence for increased cardiovascular risk in T2DM patients exposed to saxagliptin for > 1 year. On the basis of this clinical profile, saxagliptin is an attractive option for initial and add-on therapy for T2DM patients with inadequate glycemic control.

Efficacy and safety of saxagliptin in drug-naïve Asian patients with type 2 diabetes mellitus: a randomized controlled trial

BACKGROUND

Few studies have assessed the use of new oral anti-diabetic agents in Asian populations. This study assesses the efficacy and safety of saxagliptin versus placebo in Asian patients with type 2 diabetes mellitus (T2DM).

MATERIALS AND METHODS

Five hundred sixty-eight drug-naïve adult patients with T2DM and glycated haemoglobin levels (HbA(1c)) of 7.0-10.0% (53-86 mmol/mol) were randomized 1 : 1 to receive saxagliptin 5 mg daily or placebo. Efficacy endpoints included changes from baseline to week 24 in HbA(1c) , fasting plasma glucose (FPG), post-prandial glucose area under the curve from 0 to 180 min (PPG AUC(0-180)), and the proportion of patients achieving HbA(1c) <7.0% (53 mmol/mol). Adverse events (AEs) and serious AEs (SAEs) were evaluated.

RESULTS

Saxagliptin provided statistically significant adjusted mean decreases from baseline to week 24 compared with placebo, respectively, in HbA(1c) (-0.84% [-9 mmol/mol] versus -0.34% [-4 mmol/mol]; p < 0.0001), FPG (-0.90 versus -0.17 mmol/L; p < 0.0001), and PPG AUC(0-180) (-417 versus -235 mmol · min/L; p = 0.0010). A significantly greater proportion of patients achieved a therapeutic glycaemic response (HbA(1c) <7.0% [53 mmol/mol]) with saxagliptin (45.8%) versus placebo (28.8%; p < 0.0001). The proportions of patients who experienced ≥1 AE (excluding hypoglycaemia) was 43.3% for saxagliptin and 35.6% for placebo. Few patients in either treatment group experienced an SAE (2.8%, saxagliptin; 1.4%, placebo). A low proportion of patients reported hypoglycaemic events (1.8%, saxagliptin; 0.7%, placebo).

CONCLUSIONS

Saxagliptin improved glycaemic control and was well tolerated in drug-naïve Asian patients with T2DM.

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.

Efficacy and safety of exenatide once weekly versus metformin, pioglitazone, and sitagliptin used as monotherapy in drug-naive patients with type 2 diabetes (DURATION-4): a 26-week double-blind study

OBJECTIVE

To test the safety and efficacy of exenatide once weekly (EQW) compared with metformin (MET), pioglitazone (PIO), and sitagliptin (SITA) over 26 weeks, in suboptimally treated (diet and exercise) drug-naive patients with type 2 diabetes.

RESEARCH DESIGN AND METHODS

Patients were randomized to subcutaneous (SC) EQW 2.0 mg + oral placebo (n = 248), MET 2,000 mg/day + SC placebo (n = 246), PIO 45 mg/day + SC placebo (n = 163), or SITA 100 mg/day + SC placebo (n = 163) for 26 weeks. MET and PIO therapies were increased to maximum-tolerated dosages. Injections with EQW or placebo were administered weekly, while oral medication or placebo was administered daily.

RESULTS

Baseline characteristics were as follows: 59% men, 67% Caucasian, mean age 54 years, HbA(1c) 8.5%, fasting serum glucose 9.9 mmol/L, body weight 87.0 kg, and diabetes duration 2.7 years. HbA(1c) reductions (%) at 26 weeks (least-squares means) with EQW versus MET, PIO, and SITA were -1.53 vs. -1.48 (P = 0.620), -1.63 (P = 0.328), and -1.15 (P < 0.001), respectively. Weight changes (kg) were -2.0 vs. -2.0 (P = 0.892), +1.5 (P < 0.001), and -0.8 (P < 0.001), respectively. Common adverse events were as follows: EQW, nausea (11.3%) and diarrhea (10.9%); MET, diarrhea (12.6%) and headache (12.2%); PIO, nasopharyngitis (8.6%) and headache (8.0%); and SIT, nasopharyngitis (9.8%) and headache (9.2%). Minor (confirmed) hypoglycemia was rarely reported. No major hypoglycemia occurred.

CONCLUSIONS

EQW was noninferior to MET but not PIO and superior to SITA with regard to HbA(1c) reduction at 26 weeks. Of the agents studied, EQW and MET provided similar improvements in glycemic control along with the benefit of weight reduction and no increased risk of hypoglycemia.

Pharmacology of dipeptidyl peptidase-4 inhibitors: similarities and differences

The dipeptidyl peptidase (DPP)-4 inhibitors, which enhance glucose-dependent insulin secretion from pancreatic β cells by preventing DPP-4-mediated degradation of endogenously released incretin hormones, represent a new therapeutic approach to the management of type 2 diabetes mellitus. The 'first-in-class' DPP-4 inhibitor, sitagliptin, was approved in 2006; it was followed by vildagliptin (available in the EU and many other countries since 2007, although approval in the US is still pending), saxagliptin (in 2009), alogliptin (in 2010, presently only in Japan) and linagliptin, which was approved in the US in May 2011 and is undergoing regulatory review in Japan and the EU. As the number of DPP-4 inhibitors on the market increases, potential differences among the different members of the class become important when deciding which agent is best suited for an individual patient. The aim of this review is to provide a comprehensive and updated comparison of the pharmacodynamic and pharmacokinetic properties of DPP-4 inhibitors, and to pinpoint pharmacological differences of potential interest for their use in therapy. Despite their common mechanism of action, these agents show significant structural heterogeneity that could translate into different pharmacological properties. At the pharmacokinetic level, DPP-4 inhibitors have important differences, including half-life, systemic exposure, bioavailability, protein binding, metabolism, presence of active metabolites and excretion routes. These differences could be relevant, especially in patients with renal or hepatic impairment, and when considering combination therapy. At the pharmacodynamic level, the data available so far indicate a similar glucose-lowering efficacy of DPP-4 inhibitors, either as monotherapy or in combination with other hypoglycaemic drugs, a similar weight-neutral effect, and a comparable safety and tolerability profile. Data on nonglycaemic parameters are scant at present and do not allow a comparison among DPP-4 inhibitors. Several phase III trials of DPP-4 inhibitors are currently ongoing; these trials, along with post-marketing surveillance data, will hopefully increase our knowledge about the long-term efficacy and safety of DPP-4 inhibitor therapy, the effect on pancreatic cell function and peripheral glucose metabolism, and the effect on cardiovascular outcomes in patients with type 2 diabetes.

Saxagliptin for the treatment of type 2 diabetes mellitus: assessing cardiovascular data

Patients with type 2 diabetes mellitus (T2DM) are at high risk for cardiovascular (CV) disease; however, conclusive evidence that glycemic control leads to improved cardiovascular outcomes is lacking. Saxagliptin is a potent, selective dipeptidyl peptidase-4 inhibitor approved as an adjunct to diet and exercise to improve glycemic control in adults with T2DM. Saxagliptin was evaluated in a series of phase III trials as monotherapy; add-on therapy to metformin, a sulfonylurea, or a thiazolidinedione; and as initial therapy in combination with metformin. Saxagliptin consistently improved glycemic control (as reflected by significant decreases in glycated hemoglobin, fasting plasma glucose, and postprandial glucose compared with controls) and was generally well tolerated. In these analyses, saxagliptin had clinically neutral effects on body weight, blood pressure, lipid levels, and other markers of CV risk compared with controls. A retrospective meta-analysis of 8 phase II and phase III trials found no evidence that saxagliptin increases CV risk in patients with T2DM (Cox proportional hazard ratio, 0.43; 95% CI, 0.23-0.80 for major adverse cardiovascular events retrospectively adjudicated). Instead, it raised the hypothesis that saxagliptin may reduce the risk of major adverse CV events. A long-term CV outcome trial, Saxagliptin Assessment of Vascular Outcomes Recorded in Patients with Diabetes Mellitus-THrombolysis in Myocardial Infarction 53 (SAVOR-TIMI 53) is currently ongoing to determine whether saxagliptin reduces CV risk in T2DM.

DPP-4 inhibitors and lipids: systematic review and meta-analysis

INTRODUCTION

Lipid profile is an important determinant of cardiovascular risk in type 2 diabetic patients. Available glucose-lowering agents can affect lipid levels. Dipeptidyl peptidase-4 (DPP-4) inhibitors have been reported to reduce total cholesterol, but results are inconsistent across trials. The present metaanalysis was designed to assess the effect of DPP-4 inhibitors on blood lipids, verifying possible differences across compounds of this class.

METHODS

An extensive search of Medline and the Cochrane Library (any date up to December 31, 2010, restricted to randomized clinical trials, published in English) was performed for all trials containing, in any field, the words "sitagliptin," "vildagliptin," "saxagliptin," "alogliptin," "linagliptin," and/or "dutogliptin." Completed but unpublished trials were identified through a search of the ClinicalTrials.gov website, using the same keywords as above. Differences in the endpoint levels and absolute or percent variations of lipids were assessed. A metaregression was performed on the trials specified above to assess the effect of putative moderators on the effect of DPP-4 inhibitors on plasma lipids, considering all drugs together and each one separately.

RESULTS

Although the number of trials of appropriate size and duration was high (n=53), only a small fraction of those (n=17) reported data on endpoint total, high-density lipoprotein, and low-density lipoprotein cholesterol, and triglyceride. The difference-in-means for endpoint versus baseline total cholesterol in patients on DPP-4 inhibitors treatment was significantly higher in comparison with controls, meaning that treatment with DPP-4 inhibitors is associated with a significant reduction in total cholesterol (-0.18 [-0.29; -0.06] mmol/L (-7.0 [-11.2; -2.50] mg/dL); P=0.002).

CONCLUSIONS

This meta-analysis suggests a possible beneficial effect of DPP-4 inhibitors on cholesterol, which, although small, could contribute to the reduction of cardiovascular risk.

Fixed-dose combinations for treatment of type 2 diabetes mellitus

INTRODUCTION

Combining antihyperglycemic agents with complementary mechanisms of action is a cornerstone of type 2 diabetes mellitus (T2DM) management. Although several fixed-dose combinations (FDCs) are available, representing standard types of combination therapy in T2DM, use of these products has been limited.

METHODS

To address the likely concerns of prescribers and patients regarding the use of FDCs in the treatment of T2DM, literature searches were performed to ascertain the bioavailability, efficacy, tolerability, and cost-effectiveness of the currently approved FDCs compared with their individual component drugs given as separate pills in combination. Additionally, data were collected on rates of adherence, clinical outcomes, and overall treatment costs with FDCs versus dual therapy with the same constituent drugs.

RESULTS

Bioavailability is equivalent for FDCs and dual therapy used in T2DM. Efficacy and tolerability also appear to be at least as good with FDCs as with dual therapy. Retrospective analyses have suggested that FDCs can enhance adherence to therapy, presumably as a result of the reduction in pill burden, and improved adherence may result in improved glycemic control and reduced disease management costs. In addition, because currently available FDCs come in two or more dose-strength formulations, they also afford some measure of dosing flexibility.

CONCLUSIONS

The available evidence supports the wider use of FDCs in the treatment of patients with T2DM.

The cost-effectiveness of saxagliptin versus NPH insulin when used in combination with other oral antidiabetes agents in the treatment of type 2 diabetes mellitus in Poland

BACKGROUND

This study compared the health and economic benefits of saxagliptin versus insulin as second-line therapy with either metformin (MET) or sulfonylurea (SU) after failure of the respective monotherapies for patients with type 2 diabetes in Poland.

METHODS

The cost-effectiveness was assessed using a previously published diabetes model. Disease progression, utilities, and effects of changes in glycosylated hemoglobin (HbA1c), weight, and hypoglycemic events were taken from published studies, and Polish sources were used where possible.

RESULTS

MET + saxagliptin reduced severe hypoglycemic complications and weight versus MET + insulin, with an incremental benefit of 0.13 quality-adjusted life-years (QALYs) and incremental cost-effectiveness ratio (ICER) of 27,454 Polish zloty (PLN) ($9,966 U.S.) per QALY gained. SU + saxagliptin showed an incremental benefit of 0.14 QALYs and ICER of 24,663 PLN ($8,953 U.S.) per QALY gained versus SU + insulin, with reduced incidence of symptomatic and severe hypoglycemias. Results were most sensitive to disutilities associated with weight gain, hypoglycemia, injection fear, HbA1c changes, threshold for switching treatment, and patients' age. Results were robust to various model assumptions and inputs. Using a willingness-to-pay threshold of 100,000 PLN ($36,300 U.S.) per QALY gained, the probability that saxagliptin is cost-effective in these analyses was 74% (MET) and 76% (SU).

CONCLUSIONS

Saxagliptin in combination with MET or SU is likely to represent a cost-effective treatment option in Polish patients with type 2 diabetes failing first-line treatment.

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.