Meta-analysis of the cardiovascular outcomes with dipeptidyl peptidase 4 inhibitors: validation of the current FDA mandate

The Effect of Dipeptidyl Peptidase-4 Inhibitors on Macrovascular and Microvascular Complications of Diabetes Mellitus: A Systematic Review

Background

The World Health Organization estimates that diabetes is the seventh leading cause of death. Uncontrolled diabetes may cause severe consequences such as cardiovascular (CV) events (myocardial infarction, stroke, or CV mortality), lower-extremity amputations, and end-stage renal disease. Microvascular complications include retinopathy, autonomic and peripheral neuropathy, nephropathy, and diabetic ulcers. Major CV outcomes trials that were by the Food and Drug Administration for all new antihyperglycemia medications for patients at high risk for CV events were recently completed for all 4 US-marketed dipeptidyl peptidase-4 (DPP-4) inhibitors.

Objective

To present a comprehensive review of the clinical trials that evaluate macrovascular and microvascular complications reported with DPP-4 inhibitors in patients with type 2 diabetes mellitus.

Methods

In this review, we analyzed published articles in PubMed and Ovid databases between January 2008 and September 2019 that evaluated the effect of DPP-4 inhibitors on macrovascular and microvascular complications in patients with type 2 diabetes mellitus.

Results

A total of 18 studies, which included randomized controlled trials and meta-analyses were assessed. Current evidence demonstrates that the addition of DPP-4 inhibitors to standard antihyperglycemic and CV risk reduction treatment has not shown CV benefit relative to placebo in contrast to recently published studies for other medications within the glucagon-like peptide 1 agonist and sodium-glucose co-transporter 2 inhibitor classes. Notably, the potential risk for heart failure hospitalizations may exist for saxagliptin, and this effect is not extrapolated as a class effect. Based on our review, DPP-4 inhibitors may not influence microvascular complications in patients with diabetes. However, some studies have shown that saxagliptin and linagliptin may slow down the progression of albuminuria in patients with type 2 diabetes mellitus. The overall quality of the studies included in this review was high due to the inclusion of randomized controlled trials and meta-analyses.

Conclusions

DPP-4 inhibitors were found to have a neutral effect on macrovascular and microvascular complications, with the exception of saxagliptin, which may increase the risk for heart failure hospitalizations.

Cardiovascular safety of DPP-4 inhibitors compared with sulphonylureas: Results of randomized controlled trials and observational studies

After failure of metformin monotherapy, another glucose-lowering agent should be added to improve glucose control. The clinician has several pharmacological choices, including the addition of a sulphonylurea (SU) or a dipeptidyl peptidase-4 inhibitor (DPP-4i). While the cardiovascular safety of SUs remains a matter of controversy, DPP-4is have proven their non-inferiority vs placebo in recent cardiovascular (CV) outcome trials. In the absence of a head-to-head CV outcome trial-the CAROLINA, comparing linagliptin with glimepiride, is still ongoing-only indirect information can be found in the literature to compare CV outcomes (major CV events, myocardial infarction, ischaemic stroke, CV death and all-cause mortality) in patients with type 2 diabetes mellitus (T2DM) treated with SUs or DPP-4is. Thus, this comprehensive review summarizes the CV outcomes (excluding heart failure) reported in meta-analyses of randomized controlled trials (RCTs) of SUs vs placebo or other glucose-lowering agents, DPP-4is vs placebo or other glucose-lowering agents and SUs vs DPP-4is in phase-II/III studies. Also, the results of observational studies reporting CV events in patients treated with either SUs or DPP-4is have been carefully examined. Overall, the CV safety of SUs appears to be poorer than that of DPP-4is in both RCTs and cohort studies. However, the results are somewhat disparate, and such heterogeneity may be explained by different patient characteristics across studies, but also perhaps by differences between various molecules in each pharmacological class. In particular, some doubt about a class effect affecting SU CV safety has been raised. The results of CAROLINA are expected to shed more light on SU CV concerns, especially compared with DPP-4is.

The cardiovascular effect of incretin-based therapies among type 2 diabetes: a systematic review and network meta-analysis

OBJECTIVE

To evaluate the comparative cardiovascular safety of incretin-based therapies in patients with type 2 diabetes mellitus (T2DM).

METHODS

Medline, Embase, the Cochrane Library and www.clinicaltrials.gov were searched for randomized controlled trials (RCTs) with duration≥12 weeks. Network meta-analysis was performed, followed by subgroup analysis and meta-regression. The Grading of Recommendations Assessment, Development and Evaluation system was used to assess the quality of evidence. The outcome of interest was a composite of cardiovascular death, myocardial infarction, stroke and heart failure. Odds ratio (OR) with 95% confidence interval (CI) was calculated as the measure of effect size.

RESULTS

281 RCTs (76.9% double-blinded) with 180,000 patients were included, comparing incretin-based therapies with other six classes of anti-diabetic drugs or placebo. A statistically significant reduction in the risk of cardiovascular events was found in favour of GLP-1RAs when compared with placebo (OR 0.89, 95%CI: 0.80-0.99) and sulfonylurea (OR 0.76, 95%CI: 0.59-0.99), whereas DPP-4 inhibitors showed a neutral effect compared with placebo (OR 0.92, 95%CI: 0.83-1.01).

CONCLUSIONS

Incretin-based therapies show similar cardiovascular risk in comparison with metformin, insulin, thiazolidinediones, alpha-glucosidase inhibitor and sodium-glucose co-transporter 2. GLP-1RA could decrease the risk compared with sulfonylurea or placebo, while DPP-4I appears to have neutral effect on cardiovascular risk.

Network meta-analysis of cardiovascular outcomes in randomized controlled trials of new antidiabetic drugs

BACKGROUND

Randomized controlled trials (RCTs) directly comparing cardiovascular outcomes of new antidiabetic drugs are lacking. We used network meta-analysis to compare new antidiabetic drug classes with respect to major adverse cardiovascular events (MACE) and mortality.

METHODS

We searched MEDLINE, EMBASE, the Cochrane database, and ClinicalTrials.gov up to 30 December 2016 for RCTs involving SGLT-2 inhibitors, glucagon-like peptide-1 receptor agonists (GLP-1 RAs) and dipeptidyl peptidase-4 (DPP-4) inhibitors in diabetic patients that reported MACE and deaths. Outcomes were compared with frequentist and Bayesian methods using R statistics.

RESULTS

Seven RCTs with altogether 62,268 patients were included in the network meta-analysis. The SGLT-2 inhibitor and GLP-1 RAs reduced MACE (OR 0.85, 95%CI 0.73-0.99 and 0.89, 0.82-0.97, respectively) and all-cause mortality (0.67, 0.55-0.81 and 0.89, 0.80-0.99, respectively) compared to placebo. Furthermore, the SGLT-2 inhibitor reduced all-cause mortality compared to GLP-1 RAs (0.76, 0.61-0.94). In contrast, DPP-4 inhibitors did not reduce MACE or mortality compared to placebo and were associated with higher all-cause mortality compared to the SGLT-2 inhibitor (1.53, 1.24-1.89) and GLP-1 RAs (1.16, 1.01-1.33).

CONCLUSIONS

All-cause mortality and MACE were reduced by the SGLT-2 inhibitor and GLP-1 RAs, but not DPP-4 inhibitors. The SGLT-2 inhibitor had the most beneficial impact on all-cause mortality. DPP-4 inhibitors showed no cardiovascular benefit and were inferior to the other two drug classes in preventing deaths.

Cardiovascular Safety of Incretin-Based Therapies in Type 2 Diabetes: Systematic Review of Integrated Analyses and Randomized Controlled Trials

Introduction

Regulatory requirements mandate that new drugs for treatment of patients with type 2 diabetes mellitus (T2DM), such as dipeptidyl peptidase-4 (DPP-4) inhibitors and glucagon-like peptide-1 (GLP-1) receptor agonists, are evaluated to show that they do not increase cardiovascular (CV) risk.

Methods

A systematic review was undertaken to evaluate the association between DPP-4 inhibitor and GLP-1 receptor agonist use and major adverse cardiac events (MACE). The National Institutes of Health Medline database was searched for pooled analyses, meta-analyses, and randomized controlled trials (RCTs) of DPP-4 inhibitors and GLP-1 receptor agonists that included CV endpoints.

Results

Thirty-six articles met the inclusion criteria encompassing 11 pooled analyses, 17 meta-analyses, and eight RCTs (including secondary analyses). Over the short term (up to 4 years), patients with T2DM exposed to a DPP-4 inhibitor or GLP-1 receptor agonist were not at increased risk for MACE (or its component endpoints) compared with those who received comparator agents. Two meta-analyses showed a significant reduction in the incidence of MACE associated with DPP-4 inhibitor therapy as a drug class, but this beneficial effect was not observed in other meta-analyses that included large RCT CV outcome studies. In four RCTs that evaluated alogliptin, saxagliptin, sitagliptin, or lixisenatide, there was no overall increased risk for MACE relative to placebo in T2DM patients at high risk for CV events or with established CV disease, although there was an increased rate of hospitalization for heart failure associated with saxagliptin. A fifth RCT showed that liraglutide reduced MACE risk by 13% versus placebo.

Conclusion

Overall, incretin therapy does not appear to increase risk for MACE in the short term.

Adverse effects of incretin-based therapies on major cardiovascular and arrhythmia events: meta-analysis of randomized trials

BACKGROUND

Recent cardiovascular outcome trials of incretin-based therapies (IBT) in type 2 diabetes have not demonstrated either benefit or harm in terms of major adverse cardiovascular events (MACE). Earlier meta-analyses showed conflicting results but were limited in methodology. We aimed to perform an updated meta-analysis of all available incretin therapies on the incidence of MACE plus arrhythmia and heart failure.

METHODS

We identified studies published through November 2014 by searching electronic databases and reference lists. We included RCTs in which the intervention group received incretin-based therapies and the control group received placebo or standard treatment; enrolled >100 participants in each group; interventions lasted >24 weeks; and reported data on one or more primary major adverse cardiovascular events endpoints plus terms for arrhythmia and heart failure. We used the Peto method for each CV event for individual IBT treatment.

RESULTS

In this meta-analysis of 100 RCTs involving 54,758 incretin-based therapies users and 48,175 controls, exenatide was associated with increased risk of arrhythmia (OR 2.83; 95% CI, 1.06-7.57); saxagliptin was associated with an increased risk of heart failure (OR 1.23; 95% CI, 1.03-1.46), and sitagliptin was associated with a significantly decreased risk of all cause death compared to active controls (OR 0.39, 95% CI 0.18-0.82).

CONCLUSIONS

In type 2 diabetes, exenatide may increase the risk of arrhythmia, and sitagliptin may reduce the risk of all cause death; however, the subgroup of patients most likely to experience harm or benefit is unclear. Copyright © 2016 John Wiley & Sons, Ltd.

Analyses of Results From Cardiovascular Safety Trials With DPP-4 Inhibitors: Cardiovascular Outcomes, Predefined Safety Outcomes, and Pooled Analysis and Meta-analysis

The U.S. Food and Drug Administration requires that the cardiovascular (CV) safety of all new drugs for diabetes be demonstrated through pooled analyses of phase III studies or specifically designed trials. This requirement prompted several placebo-controlled, noninferiority CV safety trials in high-risk patients; to date, all completed trials showed that dipeptidyl peptidase (DPP)-4 inhibitors do not increase or reduce the risk of major CV events. These results apparently contrast with those of pooled analyses and meta-analyses of previous, smaller trials with metabolic end points, which had suggested a reduction of risk. However, the design of CV trials, which were required to demonstrate safety, is not adequate (for duration, management of concurrent therapies, etc.) for the assessment of potential therapeutic benefits. In addition, CV safety trials enroll patients at high risk of CV events, who are different from those included in earlier trials with metabolic end points. Differences in characteristics of patients enrolled probably account for most of the discrepancy in CV outcomes between CV safety studies and earlier trials. The availability of several large-scale trials with longer duration provides the unique opportunity for assessment of the safety of DPP-4 inhibitors not only with respect to major CV events but also with reference to other safety issues. For example, CV safety trials can be a source of information for pancreatitis, cancer, or hypoglycemia.

Dipeptidyl peptidase-4 inhibitor use in patients with type 2 diabetes and cardiovascular disease or risk factors

OBJECTIVES

Management of cardiovascular (CV) risk is an essential aspect of diabetes care, and acceptable CV risk is a requirement for antidiabetes medications. Dipeptidyl peptidase-4 (DPP-4) inhibitors effectively reduce glycated hemoglobin, with a low risk of hypoglycemia and weight gain. The purpose of this review is to discuss the use of DPP-4 inhibitors in patients with type 2 diabetes mellitus (T2DM) and CV disease or risk factors.

METHODS

A PubMed search (January 2013-June 2015) was conducted to identify prospective trials, meta-analyses, pooled analyses and cohort studies evaluating CV outcomes with DPP-4 inhibitors.

RESULTS

Meta-analyses, pooled analyses and retrospective cohort studies in patients with T2DM suggest no increased CV risk and possible CV benefit compared with some antidiabetes medications. The three published, long-term, prospective, randomized, double-blind CV outcomes trials in patients with CV disease or risk factors found no increased rate of major CV events in patients treated with alogliptin, saxagliptin or sitagliptin versus placebo as add-on to standard-of-care. However, the analysis of the components of the secondary end point of the saxagliptin study showed an increased number of hospitalizations for heart failure (HF) in treated patients versus placebo. A post hoc analysis of the alogliptin study showed no increase in HF hospitalization in treated patients with a history of HF versus placebo, but did show an increase in alogliptin-treated patients with no baseline HF history. Sitagliptin showed no increased risk for HF hospitalization versus placebo in the overall cohort. Two CV outcomes trials for linagliptin are ongoing.

CONCLUSION

The majority of available data from CV outcomes trials suggest a neutral effect of DPP-4 inhibitors on major CV events.

Diabetes therapies in hemodialysis patients: Dipeptidase-4 inhibitors

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

DPP-4 inhibitors: pharmacological differences and their clinical implications

INTRODUCTION

Recently, incretin-based therapy was introduced for the treatment of type 2 diabetes (T2D). In particular, dipeptidyl peptidase-4 inhibitors (DPP-4i) (sitagliptin, vildagliptin, saxagliptin, linagliptin and alogliptin) play an increasing role in the management of T2D.

AREAS COVERED

An extensive literature search was performed to analyze the pharmacological characteristics of DPP-4i and their clinical implications.

EXPERT OPINION

DPP-4i present significant pharmacokinetic differences. They also differ in chemical structure, in the interaction with distinct subsites of the enzyme and in different levels of selectivity and potency of enzyme inhibition. Moreover, disparities in the effects on glycated hemoglobin, glucagon-like peptide-1 and glucagon levels and on glucose variability have been observed. However, indirect comparisons indicate that all DPP-4i have a similar safety and efficacy profiles. DPP-4i are preferred in overweight/obese and elderly patients because of the advantages of minimal or no influence on weight gain and low risk of hypoglycemia. For the same reasons, DPP-4i can be safely combined with insulin. However, currently cardiovascular outcomes related to DPP-4i are widely debated and the available evidence is controversial. Today, long-term studies are still in progress and upcoming results will allow us to better define the strengths and limits of this therapeutic class.

Cardiovascular effects of dipeptidyl peptidase-4 inhibitors in diabetic patients: A meta-analysis

BACKGROUND

Dipeptidyl peptidase-4 inhibitors (DPP-4is) improve glucose control in patients with type 2 diabetes mellitus (DM); however, only few studies were properly designed to evaluate their cardiovascular (CV) effects. The purpose of this study was to assess the impact of DPP-4i treatment on CV morbidity and mortality.

METHODS

Randomized clinical trials enrolling more than 200 patients, comparing DPP-4 versus placebo or active treatments in patients with DM and reporting at least one event among all-cause and CV mortality, myocardial infarction (MI), stroke and new onset of heart failure (HF) were included in the analysis.

RESULTS

Ninety-four trials enrolling 85,224 patients (median follow-up=29weeks) were included in the analysis. Compared to control, treatment with DPP-4i did not affect all-cause and CV mortality, as well as stroke, in the short and long terms (< and >=29weeks, respectively). DPP-4i reduced the risk of MI in the short (RR: 0.584 [95% CI: 0.361 to 0.943]; p=0.028), but not in the long term. Additionally, long-term treatment with DPP-4 was associated with a 15.8% increased risk of HF (RR: 1.158 [CI: 1.011 to 1.326]; p=0.034). No heterogeneity among studies or publication bias was detected.

CONCLUSIONS

DPP4is do not affect all cause- and CV-mortality and stroke in diabetic patients; the reduction in MI observed with short-term treatment does not persist in the long term. Long-term use of DPP-4i in diabetic patients is associated with increased risk of HF.

Recent advances in pharmacotherapy for hypertriglyceridemia

Elevated plasma triglyceride (TG) concentrations are associated with an increased risk of atherosclerotic cardiovascular disease (CVD), hepatic steatosis and pancreatitis. Existing pharmacotherapies, such as fibrates, n-3 polyunsaturated fatty acids (PUFAs) and niacin, are partially efficacious in correcting elevated plasma TG. However, several new TG-lowering agents are in development that can regulate the transport of triglyceride-rich lipoproteins (TRLs) by modulating key enzymes, receptors or ligands involved in their metabolism. Balanced dual peroxisome proliferator-activated receptor (PPAR) α/γ agonists, inhibitors of microsomal triglyceride transfer protein (MTTP) and acyl-CoA:diacylglycerol acyltransferase-1 (DGAT-1), incretin mimetics, and apolipoprotein (apo) B-targeted antisense oligonucleotides (ASOs) can all decrease the production and secretion of TRLs; inhibitors of cholesteryl ester transfer protein (CETP) and angiopoietin-like proteins (ANGPTLs) 3 and 4, monoclonal antibodies (Mabs) against proprotein convertase subtilisin/kexin type 9 (PCSK9), apoC-III-targeted ASOs, selective peroxisome proliferator-activated receptor modulators (SPPARMs), and lipoprotein lipase (LPL) gene replacement therapy (alipogene tiparvovec) enhance the catabolism and clearance of TRLs; dual PPAR-α/δ agonists and n-3 polyunsaturated fatty acids can lower plasma TG by regulating both TRL secretion and catabolism. Varying degrees of TG reduction have been reported with the use of these therapies, and for some agents such as CETP inhibitors and PCSK9 Mabs findings have not been consistent. Whether they reduce CVD events has not been established. Trials investigating the effect of CETP inhibitors (anacetrapib and evacetrapib) and PCSK9 Mabs (AMG-145 and REGN727/SAR236553) on CVD outcomes are currently in progress, although these agents also regulate LDL metabolism and, in the case of CETP inhibitors, HDL metabolism. Further to CVD risk reduction, these new treatments might also have a potential role in the management of diabetes and non-alcoholic fatty liver disease owing to their insulin-sensitizing action (PPAR-α/γ agonists) and potential capacity to decrease hepatic TG accumulation (PPAR-α/δ agonists and DGAT-1 inhibitors), but this needs to be tested in future trials. We summarize the clinical trial findings regarding the efficacy and safety of these novel therapies for hypertriglyceridemia.