Use of dipeptidyl peptidase-4 inhibitors and the reporting of infections: a disproportionality analysis in the World Health Organization VigiBase

Pathobiological mechanisms underlying metabolic syndrome (MetS) in chronic obstructive pulmonary disease (COPD): clinical significance and therapeutic strategies

Chronic obstructive pulmonary disease (COPD) is a major incurable global health burden and is currently the 4th largest cause of death in the world. Importantly, much of the disease burden and health care utilisation in COPD is associated with the management of its comorbidities (e.g. skeletal muscle wasting, ischemic heart disease, cognitive dysfunction) and infective viral and bacterial acute exacerbations (AECOPD). Current pharmacological treatments for COPD are relatively ineffective and the development of effective therapies has been severely hampered by the lack of understanding of the mechanisms and mediators underlying COPD. Since comorbidities have a tremendous impact on the prognosis and severity of COPD, the 2015 American Thoracic Society/European Respiratory Society (ATS/ERS) Research Statement on COPD urgently called for studies to elucidate the pathobiological mechanisms linking COPD to its comorbidities. It is now emerging that up to 50% of COPD patients have metabolic syndrome (MetS) as a comorbidity. It is currently not clear whether metabolic syndrome is an independent co-existing condition or a direct consequence of the progressive lung pathology in COPD patients. As MetS has important clinical implications on COPD outcomes, identification of disease mechanisms linking COPD to MetS is the key to effective therapy. In this comprehensive review, we discuss the potential mechanisms linking MetS to COPD and hence plausible therapeutic strategies to treat this debilitating comorbidity of COPD.

Cyclo-oxygenase selectivity and chemical groups of nonsteroidal anti-inflammatory drugs and the frequency of reporting hypersensitivity reactions: a case/noncase study in VigiBase

To date, no reports of hypersensitivity reactions (HSRs) among nonsteroidal anti-inflammatory drugs (NSAIDs) according to cyclo-oxygenase (COX) selectivity and chemical groups have been published in a single study. The present study assessed the reporting frequency of HSRs for NSAIDs based on their relative inhibitory potency toward COX enzymes and chemical groups, including the presence/absence of a functional sulfonamide group, in strata observed 5 years after market authorization. A case/noncase study was performed among individual case safety reports (ICSRs) with NSAIDs as suspected drugs in VigiBase, the WHO spontaneous reporting database. Cases were ICSRs mentioning angioedema and anaphylactic/anaphylactoid shock conditions, while noncases were ICSRs without HSRs. NSAIDs were categorized into (i) NSAIDs with high COX-2 selectivity (coxibs), (ii) noncoxib NSAIDs with COX-2 preference, (iii) NSAIDs with poor selectivity, or (iv) NSAIDs with unknown selectivity. Chemical groups were defined based on the Anatomical Therapeutic Chemical classification system and the presence/absence of a functional sulfonamide group. Reporting odds ratios (RORs) and 95% confidence intervals (95% CIs) were calculated using logistic regression analysis. We identified 13 229 cases and 106 444 noncases. In the first 5 years after marketing, poor-selectivity NSAIDs and acetic acid derivatives were associated with the highest ROR of HSRs (age- and sex-adjusted ROR 2.12, 95% CI 1.98-2.28; and ROR 2.21, 95% CI 1.83-2.66, respectively) compared with coxibs, and sulfonamide NSAIDs were associated with the highest ROR of HSRs compared with nonsulfonamide NSAIDs (age- and sex-adjusted ROR 1.38, 95% CI 1.29-1.47). After the first 5 years of marketing, most of the RORs returned to approximately 1.

Use of dipeptidyl peptidase-4 inhibitors and the risk of arthralgia: Population-based cohort and nested case-control studies

PURPOSE

The objective of this study was to investigate the association between the administration of dipeptidyl peptidase-4 (DPP-4) inhibitors (cumulative duration, timing, and individual substance) and the risk of arthralgia by using a nationwide database with two methodological approaches including cohort and nested case-control study designs.

METHODS

Using Taiwan's National Health Insurance Research Database, we identified patients who were newly prescribed with DPP-4 inhibitors, thiazolidinediones (TZDs), or acarbose between 1 March 2009 and 31 December 2012. The exposure of studied drugs was categorized into five exclusive categories: DPP-4 inhibitor, TZD, acarbose, combined use, or non-use, and assessed in a time-varying manner. Time-dependent Cox proportional hazard models were used to estimate the association between DPP-4 inhibitors and the risk of arthralgia. Particularly, we tested the impact of different cumulative duration, timing, and individual substance of DPP-4 inhibitors use on risk of arthralgia. A corresponding nested case-control study using conditional logistic regression was conducted to verify this association.

RESULTS

An increased risk of arthralgia was observed during the first year after initiating DPP-4 inhibitors (adjusted Hazard Ratio = 1.35; 95% confidence interval [CI], 1.04-1.75) but the risk declined with cumulative use. This duration-response relation was not found in TZDs use and acarbose use. In the nested case-control study, there was a slightly increased risk of arthralgia (aOR = 1.08; 95% CI, 1.04-1.12) associated with current DPP-4 inhibitor use.

CONCLUSION

A relatively higher risk of arthralgia was associated with the initial administration of DPP-4 inhibitors, however, the risk declined among long-term users.

Drug fever and acute inflammation from hypercytokinemia triggered by dipeptidyl peptidase-4 inhibitor vildagliptin

A 69-year-old man started taking the dipeptidyl peptidase-4 inhibitor, vildagliptin. One week later, C-reactive protein and plasma immunoglobulin E levels were markedly elevated, and the vildagliptin was stopped. After the patient's laboratory findings were normalized, we decided to restart vildagliptin with the patient's agreement. The next day, he had a high fever, and C-reactive protein and procalcitonin levels were elevated. Although we failed to find a focus of infection, we started antibiotics therapy. Two days later, the high fever had improved, and the C-reactive protein level had decreased. A drug lymphocyte stimulation test showed a positive result for vildagliptin. We examined various kinds of cytokine and infection markers just before and after the treatment with vildagliptin. Finally, we diagnosed the patient with vildagliptin-induced drug fever, probably based on the increase of various inflammatory cytokine levels and the response to this. Taken together, we should be aware of the possibility of vildagliptin inducing drug fever and/or acute inflammation.

Linagliptin safety profile: A systematic review

OBJECTIVE

To describe the safety profile of linagliptin.

METHODOLOGY

Systematic review using PubMed/MEDLINE, BVS and Web of Science. The search strategy "Linagliptin" AND "safety" was used. The inclusion criteria were clinical trials with a control group composed of conventional DM2 pharmacotherapy.

RESULTS

We identified 16 studies, and the most frequent adverse events (AEs) were nasopharyngitis with linagliptin at 5 and 10mg in monotherapy (31.6% and 29.6%, respectively) and gastrointestinal events (>10.0%) with linagliptin in combination. Of the AEs, 14.9 (±3.1)% were associated with the use of linagliptin in monotherapy, and 17.6 (±6.0)% in combination. The linagliptin AEs have a varied occurrence and frequency, ranging from mild to moderate intensity.

Comparative Safety of Dipeptidyl Peptidase-4 Inhibitors Versus Sulfonylureas and Other Glucose-lowering Therapies for Three Acute Outcomes

Although the glucose lowering effect of dipeptidyl peptidase-4 (DPP4) inhibitors is well established, several potential serious acute safety concerns have been raised including acute kidney injury, respiratory tract infections, and acute pancreatitis. Using the UK-based Clinical Practice Research Datalink (CPRD), we identified initiators (365-day washout period) of DPP4 inhibitors and relevant comparators including initiators of sulfonylureas, metformin, thiazolidinediones, and insulin between January 2007 and January 2016 to quantify the association between DPP4 inhibitors and three acute health events – acute kidney injury, respiratory tract infections, and acute pancreatitis. The associations between drug and study outcomes were estimated using Cox proportional hazard models adjusted for deciles of high-dimensional propensity scores and number of additional glucose lowering agents. After controlling for potential confounders, the risk was not significantly increased or decreased for initiators of DPP4 inhibitors compared to sulfonylureas (hazard ratio (HR) [95% confidence interval (CI)] for acute kidney injury: 0.81 [0.56–1.18]; HR for respiratory tract infections: 0.93 [0.84–1.04]; HR for acute pancreatitis 1.03 [0.42–2.52], metformin (HR for respiratory tract infection 0.91 [0.65–1.27]), thiazolidinediones (HR for acute kidney injury: 1.12 [0.60–2.10]; HR for respiratory tract infections: 1.02 [0.86–1.21]; HR for acute pancreatitis: 1.21 [0.25–5.72]), or insulin (HR for acute kidney injury: 1.40 [0.77–2.55]; HR for respiratory tract infections: 0.74 [0.60–0.92]; HR for acute pancreatitis: 1.01 [0.24–4.19]). Initiators of DPP4 inhibitors were associated with an increased risk of acute kidney injury when compared to metformin initiators (HR [95% CI] for acute kidney injury: 1.85 [1.10–3.12], although this association was attenuated when DPP4 inhibitor monotherapy was compared to metformin monotherapy exposure as a time-dependent variable (HR 1.39 [0.91–2.11]). Initiation of a DPP4 inhibitor was not associated with an increased risk of acute kidney injury, respiratory tract infections, or acute pancreatitis compared to sulfonylureas or other glucose-lowering therapies.

Drugs that increase the risk of community-acquired pneumonia: a narrative review

INTRODUCTION

Community-acquired pneumonia (CAP), a major cause of morbidity and mortality, is the leading infectious cause of death in the developed world. Population-based studies and systematic reviews have identified a large number of risk factors for the development of pneumonia in adults. In addition to age, lifestyle habits, and comorbidities, some forms of pharmacotherapy may also increase the risk for CAP.

AREAS COVERED

MEDLINE, CENTRAL, and Web of Science were used in 2017 to search for case-control, cohort studies, as well as randomized controlled trials and meta-analysis that involved outpatient proton pump inhibitors (PPIs), inhaled corticosteroids (ICSs), antipsychotics, oral antidiabetics, and CAP diagnosis in patients aged >18 years.

EXPERT OPINION

Our review confirmed that the use of ICSs, PPIs or antipsychotic drugs was independently associated with an increased risk for CAP. We also identified a positive association between specific oral antidiabetics and the development of pneumonia.

Association between dipeptidyl peptidase-4 inhibitors and urinary tract infection in elderly patients: A retrospective cohort study

PURPOSE

Dipeptidyl peptidase-4 (DPP-4) inhibitors are a new class of antidiabetic drugs. Although they have been reported to increase the risk of infection, the findings are controversial. Given that urinary tract infections (UTIs) are common in the elderly, we conducted a retrospective cohort study by using health care insurance claims data, to elucidate the association between the DPP-4 inhibitors and the incidence of UTI in latter-stage elderly patients.

METHODS

We analyzed 25,111 Japanese patients aged 75 years and older between the fiscal years 2011 and 2016. Patients using DPP-4 inhibitors and sulfonylureas (SUs) were matched at a 1:1 ratio using propensity scoring. The Incidence rate ratio (IRR) of UTI was compared between users of SUs and users of DPP-4 inhibitors by Poisson regression. Moreover, subgroup analyses stratified by sex were conducted to evaluate whether the combination of prostatic hyperplasia and DPP-4 inhibitors is associated with the incidence of UTI in male patients.

RESULTS

The use of DPP-4 inhibitors was associated with an increased risk of UTI (adjusted IRR 1.23, 95% CI [1.04-1.45]). After propensity score matching, the association remained significant (adjusted IRR 1.28, 95% CI [1.05-1.56]). Moreover, elderly male patients with prostatic hyperplasia who received DPP-4 inhibitors had a higher risk of UTI than SU users without prostatic hyperplasia (Matched: crude IRR 2.90, 95% CI [1.78-4.71]; adjusted IRR 2.32, 95% CI [1.40-3.84]).

CONCLUSIONS

The long-term use of DPP-4 inhibitors by elderly patients, particularly male patients with prostatic hyperplasia, may increase the risk of UTI.

Validity of diagnostic codes to identify hospitalizations for infections among patients treated with oral anti-diabetic drugs

PURPOSE

Identification of hospitalizations for infection is important for post-marketing surveillance of drugs, but the validity of using diagnosis codes to identify these events is unknown. Differentiating between hospitalization for and with infection is important, as the latter is common and less likely to arise from pre-admission exposure to drugs. We determined positive predictive values (PPVs) of diagnostic coding-based algorithms to identify hospitalization for infection among patients prescribed oral anti-diabetic drugs (OADs).

METHODS

We identified patients initiating OADs within 2 United States claims databases (Medicare, HealthCore Integrated Research Database^SM [HIRD^SM ]) and 2 United Kingdom electronic medical record databases (Clinical Practice Research Datalink [CPRD], The Health Improvement Network [THIN]) from 2009 to 2014. To identify potential hospitalizations for infection, we selected patients with a hospital diagnosis of infection and, within 7 days prior to hospitalization, either an outpatient/emergency department visit with an infection diagnosis or outpatient antimicrobial treatment. Hospital records were reviewed by infectious disease specialists to adjudicate hospital admissions for infection. PPVs for confirmed outcomes were determined for each database.

RESULTS

Code-based algorithms to identify hospitalization for infection had PPVs exceeding 80% within Medicare (PPV, 83% [90/109]; 95% CI, 74-89%), HIRD^SM (PPV, 89% [73/82]; 95% CI, 80-95%), and THIN (PPV, 86% [12/14]; 95% CI, 57-98%) but not within CPRD (PPV, 67% [14/21]; 95% CI, 43-85%).

CONCLUSIONS

Algorithms identifying hospitalization for infection utilizing hospital diagnoses along with antecedent outpatient/emergency infection diagnoses or antimicrobial therapy had sufficiently high PPVs for confirmed events within Medicare, HIRD^SM , and THIN to enable their use for pharmacoepidemiologic research.

Validation and incidence of community-acquired pneumonia in patients with type 2 diabetes in the BIFAP database

Oral anti-diabetic drugs (OADs) have been associated with community-acquired pneumonia (CAP). We aimed to validate the recording of CAP in the Spanish Database for Pharmacoepidemiological Research in Primary Care (BIFAP) for the future evaluation of OAD-CAP association. The incidence rate (IR/1000 person-years) of CAP in type 2 diabetes mellitus (T2DM) was also determined. In total, 2966 pneumonia records (2040 listed as diagnosis and 926 as identified from comments added by physicians) were identified from 76 009 patients with T2DM after the first OAD in 2002-2013. Data around the CAP date were reviewed: 1803 (60·9%) were classified as 'probable CAP' (confirmed by X-ray/laboratory, referral letters or CAP lung site); 589 (19·8%) as 'no-case' (486 had other illness, 78 previous CAP, 25 cancer); and 574 (19·4%) as 'possible CAP' (441 without confirmatory information, 133 with uncertain diagnosis or uncertain diagnosis date). In total, 74·2% and 31·4% of pneumonia records in the diagnosis and comments, respectively, were 'probable cases' (IR: 6·04), which increased to 90·5% and 42·9%, respectively, when the 441 'possible cases' without confirmatory information were included (IR: 7·52). In summary, diagnosis had a high positive predictive value, and adding cases automatically detected from comments decreased that value significantly.

Relevance of the Weber effect in contemporary pharmacovigilance of oncology drugs

BACKGROUND

Numerous reporting biases have been known to affect spontaneous reporting databases. The Weber effect, which constitutes a peak in adverse event (AE) reporting of a drug at the end of second year after regulatory approval followed by a continuous decline thereafter, has been considered an important bias for a long time. The existence of this bias in AE reporting of oncology drugs remains an underevaluated area, prompting a targeted examination.

METHODS

The US Food and Drug Administration (USFDA) Adverse Event Reporting System (FAERS) was studied for AE reporting patterns of 5 years of 15 new molecular entities (NMEs) and biologics used in oncology. This 5-year period started from the USFDA date of approval for the NMEs and biologics. The number of AEs reported for each of the drugs was plotted against time (years). The AE reporting patterns were specifically examined for the existence of the Weber effect. In addition, AE reporting rate patterns of 5 years of seven NMEs and biologics used in oncology were examined.

RESULTS

A total of 50,630 AE reports were logged in to the FAERS for all 15 drugs examined for AE reporting patterns. We observed five distinct AE reporting patterns for 15 drugs; however, none of the AE patterns were identical to the Weber effect. We did not observe a consistent AE reporting rate pattern for the seven drugs examined for AE reporting rates. With the exception of one drug (cetuximab), none of the drugs exhibited a second-year peak in AE reporting rates. This peak was not followed by continuous decline in AE reporting rate thereafter.

CONCLUSION

This study does not support the existence of the Weber effect in AE reporting of oncology drugs. The contemporary AE reporting of oncology drugs does not exhibit a consistent pattern.

Use of oral antidiabetic agents and risk of community-acquired pneumonia: a nested case-control study

AIMS

To evaluate the association between use of different oral antidiabetic agents (OAD) and the risk of community-acquired pneumonia (CAP) in patients with type-2 diabetes (T2DM).

METHODS

Case-control study nested in a cohort of patients with T2DM and use of OAD between 2002 and 2013, based in a Spanish general practice research database. Cases were people diagnosed with T2DM, aged >18 years and with a validated diagnosis of CAP between 2002 and 2013. Ten controls were matched on age, sex and calendar year. Odds ratio (OR) of CAP was estimated comparing patients treated with: (1) metformin vs. other monotherapies or no antidiabetic treatment; (2) metformin + sulfonylureas vs. other antidiabetic combinations. OR of CAP was also assessed according to antidiabetic treatment duration.

RESULTS

From a cohort of 76 009 T2DM patients, we identified 1803 cases of CAP. No difference in the incidence of CAP was observed when comparing any OAD in monotherapy with metformin. Compared with current use of metformin + sulfonylurea, thiazolidinediones + metformin was associated with an increased risk of CAP (adjusted OR = 2.48, 95% CI 1.40-4.38). The use of any combination with thiazolidinediones was also associated with higher risk of CAP (adjusted OR = 2.00, 95% CI 1.22-3.28). Current use of DPP-4 inhibitors was not associated with an increased risk of CAP.

CONCLUSIONS

No differences in the incidence of CAP were observed between the use of OAD in monotherapy vs. metformin. Thiazolidinedione use in combination was associated with an increase in the risk of CAP when compared to metformin + sulfonylureas. The use of DPP-4 inhibitors was not associated with an increased risk of CAP.

Genitourinary infections in diabetic patients in the new era of diabetes therapy with sodium-glucose cotransporter-2 inhibitors

AIMS

To review prevalence and significance of urinary tract (UTI) and genital infections (GI) in diabetes and the effects of sodium glucose cotransporter 2 (SGLT-2) inhibitors on these complications.

DATA SYNTHESIS

The prevalence of asymptomatic bacteriuria (ASB) is 2-3 times higher in diabetic than in non-diabetic women. The treatment of ASB has no impact on the development of UTIs and/or a decline in renal function. Therefore, there is no indication for screening for and/or treatment of ASB. The incidence of UTI is higher and frequently complicated in diabetic patients, particularly in those with longer duration of disease and of older age. There is no consistent evidence of an association between A1c levels, glycosuria and the risk of ASB and/or UTIs. Diabetes is a known risk factor for Candida colonization and GI, and a poor glycemic control is associated with a higher risk. While patients treated with SGLT-2 inhibitors may have a non-significant increased risk of UTI, they have a clearly increased risk of GI; most of these infections are mild, easy to treat, and the rate of recurrence is low.

CONCLUSION

Diabetic patients are at high risk of UTIs and of GI. Only GI are associated with poor glycemic control. Although patients treated with SGLT-2 inhibitors have an increased 3-5 fold risk of GI, proper medical education can reduce this risk.

DPP-4 Inhibition by Linagliptin Attenuates Obesity-Related Inflammation and Insulin Resistance by Regulating M1/M2 Macrophage Polarization

Dipeptidyl peptidase 4 (DPP-4) cleaves a large number of chemokine and peptide hormones involved in the regulation of the immune system. Additionally, DPP-4 may also be involved in macrophage-mediated inflammation and insulin resistance. Thus, the current study investigated the effect of linagliptin, an inhibitor of DPP-4, on macrophage migration and polarization in white adipose tissue (WAT) and liver of high-fat diet-induced obese (DIO) mice. DPP-4(+) macrophages in lean and obese mice were quantified by fluorescence-activated cell sorting (FACS) analysis. DPP-4 was predominantly expressed in F4/80(+) macrophages in crown-like structures compared with adipocytes in WAT of DIO mice. FACS analysis also revealed that, compared with chow-fed mice, DIO mice exhibited a significant increase in DPP-4(+) expression in cells within adipose tissue macrophages (ATMs), particularly M1 ATMs. Linagliptin showed a greater DPP-4 inhibition and antioxidative capacity than sitagliptin and reduced M1-polarized macrophage migration while inducing an M2-dominant shift of macrophages within WAT and liver, thereby attenuating obesity-induced inflammation and insulin resistance. Loss of macrophage inflammatory protein-1α, a chemokine and DPP-4 substrate, in DIO mice abrogated M2 macrophage-polarizing and insulin-sensitizing effects of linagliptin. Therefore, the inhibition of DPP-4 by linagliptin reduced obesity-related insulin resistance and inflammation by regulating M1/M2 macrophage status.

Cut to the chase: a review of CD26/dipeptidyl peptidase-4's (DPP4) entanglement in the immune system

CD26/DPP4 (dipeptidyl peptidase 4/DP4/DPPIV) is a surface T cell activation antigen and has been shown to have DPP4 enzymatic activity, cleaving-off amino-terminal dipeptides with either L-proline or L-alanine at the penultimate position. It plays a major role in glucose metabolism by N-terminal truncation and inactivation of the incretins glucagon-like peptide-1 (GLP) and gastric inhibitory protein (GIP). In 2006, DPP4 inhibitors have been introduced to clinics and have been demonstrated to efficiently enhance the endogenous insulin secretion via prolongation of the half-life of GLP-1 and GIP in patients. However, a large number of studies demonstrate clearly that CD26/DPP4 also plays an integral role in the immune system, particularly in T cell activation. Therefore, inhibition of DPP4 might represent a double-edged sword. Apart from the metabolic benefit, the associated immunological effects of long term DPP4 inhibition on regulatory processes such as T cell homeostasis, maturation and activation are not understood fully at this stage. The current data point to an important role for CD26/DPP4 in maintaining lymphocyte composition and function, T cell activation and co-stimulation, memory T cell generation and thymic emigration patterns during immune-senescence. In rodents, critical immune changes occur at baseline levels as well as after in-vitro and in-vivo challenge. In patients receiving DPP4 inhibitors, evidence of immunological side effects also became apparent. The scope of this review is to recapitulate the role of CD26/DPP4 in the immune system regarding its pharmacological inhibition and T cell-dependent immune regulation.

DPP-4 inhibitors and risk of infections: a meta-analysis of randomized controlled trials

BACKGROUND

To evaluate the risk of infections in the treatment of type 2 diabetes patients with dipeptidyl-peptidase 4 (DPP-4) inhibitors.

METHODS

A literature search was conducted through electronic databases. The inclusion criteria included study duration of no less than 12 weeks developed in type 2 diabetes patients, the use of a randomized control group receiving a DPP-4 inhibitor and the availability of outcome data for infections. Out of 2181 studies, 74 studies were finally included.

RESULTS

The risk of overall infection for DPP-4 inhibitors treatment was comparable to placebo (odds ratio (OR) = 0.97, 95% confidence interval (CI), 0.91 to 1.04, p = 0.40), metformin treatment (OR = 1.22, 95% CI, 0.95 to 1.56, p = 0.12), sulphonylurea treatment (OR = 1.09, 0.93 to 1.29, p = 0.29), thiazolidinedione treatment (OR = 0.86, 95% CI, 0.65 to 1.14, p = 0.29) and alpha glucosidase inhibitor treatment (OR = 1.03, 95% CI, 0.33 to 3.22, p = 0.96). When compared different DPP-4 inhibitors with placebo treatment, risks of infections were comparable for alogliptin, linagliptin, sitagliptin, saxagliptin and vildagliptin. Compared with placebo or active comparator treatment, risks of infection in different systems for DPP-4 inhibitors were all comparable.

CONCLUSIONS

The overall risk of infections of DPP-4 inhibitor was not increased compared with control groups.

Incretin therapies: highlighting common features and differences in the modes of action of glucagon-like peptide-1 receptor agonists and dipeptidyl peptidase-4 inhibitors

Over the last few years, incretin-based therapies have emerged as important agents in the treatment of type 2 diabetes (T2D). These agents exert their effect via the incretin system, specifically targeting the receptor for the incretin hormone glucagon-like peptide 1 (GLP-1), which is partly responsible for augmenting glucose-dependent insulin secretion in response to nutrient intake (the 'incretin effect'). In patients with T2D, pharmacological doses/concentrations of GLP-1 can compensate for the inability of diabetic β cells to respond to the main incretin hormone glucose-dependent insulinotropic polypeptide, and this is therefore a suitable parent compound for incretin-based glucose-lowering medications. Two classes of incretin-based therapies are available: GLP-1 receptor agonists (GLP-1RAs) and dipeptidyl peptidase-4 (DPP-4) inhibitors. GLP-1RAs promote GLP-1 receptor (GLP-1R) signalling by providing GLP-1R stimulation through 'incretin mimetics' circulating at pharmacological concentrations, whereas DPP-4 inhibitors prevent the degradation of endogenously released GLP-1. Both agents produce reductions in plasma glucose and, as a result of their glucose-dependent mode of action, this is associated with low rates of hypoglycaemia; however, there are distinct modes of action resulting in differing efficacy and tolerability profiles. Furthermore, as their actions are not restricted to stimulating insulin secretion, these agents have also been associated with additional non-glycaemic benefits such as weight loss, improvements in β-cell function and cardiovascular risk markers. These attributes have made incretin therapies attractive treatments for the management of T2D and have presented physicians with an opportunity to tailor treatment plans. This review endeavours to outline the commonalities and differences among incretin-based therapies and to provide guidance regarding agents most suitable for treating T2D in individual patients.

Use of Dipeptidyl-Peptidase-4 Inhibitors and the Risk of Pneumonia: A Population-Based Cohort Study

Background

Dipeptidyl-peptidase-4 inhibitors (DPP4Is) are drugs for the treatment of type 2 diabetes mellitus (T2DM). There is increasing evidence that DPP4Is may result in suppression of the immune system and may increase the risk of infections such as pneumonia. Aim of this study was to evaluate the association between the use of DPP4Is and the risk of pneumonia in a population-based study.

Methods

We conducted a population-based cohort study using data from the world’s largest primary care database, the UK Clinical Practice Research Datalink (CPRD). We selected all users of non-insulin antidiabetic drugs (NIADs), including DPP4Is, between 2007 and 2012. To each NIAD user, we matched randomly selected non-users. The NIAD user’s first prescription defined the index date, which was then assigned to the matched non-users. Patients were followed from their first prescription until end of data collection or the first event of pneumonia, whichever came first. Cox regression analysis estimated the association between pneumonia and current use of DPP4Is versus 1) current use of other NIADs and 2) non-users. DPP4I use was then stratified to daily and cumulative dose. Analyses were statistically adjusted for age, sex, lifestyle factors and comorbidities and concomitant use of various other drugs.

Results

Risk of pneumonia was not increased with current DPP4I use versus use of other NIADs, adjusted Hazard Ratio (HR) 0.70; 95% Confidence Interval (CI) 0.55–0.91. Also higher cumulative doses or daily doses did not further increase risk of pneumonia.

Conclusion

We found no increased risk of pneumonia in T2DM patients using DPP4Is compared to T2DM patients using other NIADs. Our finding is in line with direct and indirect evidence from observational studies and RCTs. There is probably no need to avoid prescribing of DPP4Is to elderly patients who are at risk of pneumonia.

Association between Use of Oral Anti-Diabetic Drugs and the Risk of Sepsis: A Nested Case-Control Study

Although oral antidiabetic drugs (OADs) have been associated with immunomodulation in preclinical studies, little is still known about the association between the use of OADs and the risk of sepsis. Using a cohort of patients, extracted from Taiwan's National Health Insurance Research Database, with type 2 diabetes who were newly diagnosed between 2010 and 2012 and treated with OADs, we conducted a nested case-control study involving 43,015 cases (patients who were first hospitalized for sepsis) and 43,015 matched controls. Compared with non-use, metformin use was associated with a decreased risk of developing sepsis (adjusted odds ratio [OR] 0.80, 95% confidence interval [CI] 0.77-0.83, P < 0.001), but meglitinide (adjusted OR 1.32, 95% CI 1.25-1.40, P < 0.001) use was associated with the increased risk of developing sepsis. The risk for development of sepsis was also lower among current (adjusted OR 0.87, 95% CI 0.78-0.96) and recent (adjusted OR 0.83, 95% CI 0.73-0.94) thiazolidinedione users. Current or recent sulfonylurea use and dipeptidyl peptidase-4 inhibitor use were not significantly associated with the development of sepsis. Our results highlight the need to consider the potential pleiotropic effect of OADs against sepsis in addition to the lowering of blood glucose.

Acalculous pyelonephritis and cholecystitis occurring simultaneously in a diabetic patient on sitagliptin therapy

Dipeptidyl peptidase-4 (DPP-4) inhibitors are a new class of anti-diabetic drugs. They control both fasting and postprandial hyperglycemia by inhibiting degradation of incretin hormones, such as, glucagon-like peptide-1(GLP-1) and glucose-dependent insulinotropic polypeptide (GIP). Sitagliptin is the first DPP-4 inhibitor to be marketed in India. In addition to its glucose lowering effect, it also suppresses immunity resulting in various infections in a diabetes patient. Here, we describe the simultaneous development of two infections (acalculous pyelonephritis and cholecystitis) in a postmenopausal female patient, well-controlled on sitagliptin-based anti-diabetic therapy.

Dipeptidyl peptidase-4 inhibitors and the risk of community-acquired pneumonia in patients with type 2 diabetes

AIMS

To determine whether the use of dipeptidyl peptidase-4 (DPP-4) inhibitors is associated with an increased risk of community-acquired pneumonia.

METHODS

The UK Clinical Practice Research Datalink and the Hospital Episodes Statistics database were used to conduct a nested case-control analysis within a cohort of new users of antidiabetic drugs between 2007 and 2012. Incident cases of hospitalization for community-acquired pneumonia were matched with up to 20 controls on age, duration of treated diabetes, calendar year and duration of follow-up. Conditional logistic regression models were used to estimate the odds ratios (ORs) and 95% confidence intervals (CIs) for hospitalization for community-acquired pneumonia associated with current use of DPP-4 inhibitors compared with current use of two or more oral antidiabetic drugs.

RESULTS

The cohort included 49,653 patients, of whom 562 were hospitalized for community-acquired pneumonia during follow-up (incidence rate 5.2/1000 person-years). Compared with current use of two or more oral antidiabetic drugs, current use of DPP-4 inhibitors was not associated with an increased risk of hospitalized community-acquired pneumonia overall (adjusted OR 0.80, 95% CI 0.50-1.29) or according to duration of use (p for trend = 0.57).

CONCLUSIONS

The use of DPP-4 inhibitors was not associated with an increased risk of hospitalization for community-acquired pneumonia. Additional research is needed to assess the association between these drugs and other serious infections.

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.

Efficacy and safety of linagliptin as monotherapy or add-on treatment in Asian patients with suboptimal glycemic control: a pooled analysis

AIMS

To evaluate the efficacy and safety of the dipeptidyl peptidase (DPP)-4 inhibitor linagliptin in Asian patients with type 2 diabetes mellitus (T2DM), a rapidly increasing population.

METHODS

Data were pooled for Asian patients receiving linagliptin orally once daily, as monotherapy or added to existing oral antidiabetes therapies, in multinational randomized placebo-controlled clinical trials. Efficacy data were taken from four pivotal trials with 24-week durations to allow for robust efficacy assessment. Safety data were pooled from a wider group of 10 trials with varying durations to capture the largest possible incidence of adverse events (AEs). The primary efficacy endpoint was change from baseline to week 24 in HbA1c. AEs were analyzed descriptively.

RESULTS

Mean baseline HbA1c (±SD) in this population was 8.2 ± 0.9%. Placebo-corrected mean change in HbA1c after 24 weeks was -0.79% (95% confidence interval [CI]: -0.92 to -0.67; p < 0.0001). Placebo-corrected mean change in fasting plasma glucose was -17.8 ± 2.4 mg/dL (95% CI: -22.6, -13.0; p < 0.0001). In a small subgroup, mean post-prandial glucose was reduced by a placebo-corrected -56.9 ± 14.0 mg/dL (95% CI: -85.2, -28.5). AEs occurred in 58.0% of linagliptin patients (serious AEs in 2.4%) and 58.2% of placebo patients (serious AEs in 3.0%).

CONCLUSIONS

This study was limited by the post hoc nature of the analysis, and because the pooling did not differentiate between geographically distant Asian regions. Nonetheless, this analysis provides evidence that linagliptin was efficacious and well tolerated as monotherapy or added to other oral antidiabetes therapies in Asian patients with T2DM.

DPP-4 inhibitors: focus on safety

INTRODUCTION

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

AREAS COVERED

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

EXPERT OPINION

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

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

INTRODUCTION

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

AREAS COVERED

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

EXPERT OPINION

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

Effects of dipeptidyl peptidase IV inhibitor sitagliptin on immunological parameters of lymphocytes in intact animals and animals with experimental autoimmune process

The effects of dipeptidyl peptidase IV inhibitor sitagliptin on immunological parameters were studied in animals with experimental autoimmune process. The effects of the drug administered in preventive (before manifestation of autoimmune processes) and therapeutic (after manifestation of autoimmune process) modes were studied.

The safety of dipeptidyl peptidase-4 (DPP-4) inhibitors or sodium-glucose cotransporter 2 (SGLT-2) inhibitors added to metformin background therapy in patients with type 2 diabetes mellitus: a systematic review and meta-analysis

The aim of the present meta-analysis was to assess the safety profile of dipeptidyl peptidase-4 (DPP-4) inhibitors and sodium-glucose cotransporter 2 (SGLT-2) inhibitors in comparison with placebo as add-on to metformin therapy in patients with type 2 diabetes. Randomized controlled trials and controlled clinical trials were identified by searching Pubmed, Embase and the Cochrane Central Register of Controlled Trials database until 15 July 2013. All included studies were critically appraised and analysed with the use of Review Manager 5.1.0 software according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement protocol. Twenty randomized and double-blinded studies published in 22 articles fulfilled the inclusion criteria for meta-analysis. The overall results demonstrated that the use of oral antidiabetic agents (analysed separately and together) was not associated with any significantly increased risk of any serious adverse events including hypoglycaemia and gastrointestinal disorders. Moreover, the use of DPP-4 or SGLT-2 inhibitors significantly decreased risk of diarrhoea compared with placebo, when given concomitantly with metformin. However, we found that the SGLT-2 inhibitors were more likely to cause a genital infection. Despite some limitations, the findings of this meta-analysis indicate that DPP-4 or SGLT-2 inhibitors have favourable safety profile, and such therapy, when combined with metformin is well tolerated.

Dipeptidyl peptidase-4 inhibitors: multitarget drugs, not only antidiabetes drugs

Dipeptidyl peptidase (DPP)-4 inhibitors are a new class of antidiabetic agents that reduce blood glucose by preventing the degradation of the endogenous incretin hormones glucagon-like peptide-1 and glucose-dependent insulinotropic polypeptide. Protection by DPP-4 inhibitors of β-cell function has been demonstrated in patients with type 2 diabetes. Because DPP-4 is an enzyme widely expressed in humans, DPP-4 inhibitors are speculated to be multitarget agents. However, other potential therapeutic benefits of DPP-4 inhibitors remain unknown. Recently, some therapeutic effects of DPP-4 inhibitors, such as immune regulation, cardiovascular protection, and anti-inflammatory effects, have been observed. This article provides a systematic and comprehensive review of current research into the newly found effects and mechanism of action of DPP-4 inhibitors in a therapeutic context.

Dipeptidyl peptidase-4 inhibitors in type 2 diabetes therapy--focus on alogliptin

Type 2 diabetes mellitus is a complex and progressive disease that is showing an apparently unstoppable increase worldwide. Although there is general agreement on the first-line use of metformin in most patients with type 2 diabetes, the ideal drug sequence after metformin failure is an area of increasing uncertainty. New treatment strategies target pancreatic islet dysfunction, in particular gut-derived incretin hormones. Inhibition of the enzyme dipeptidyl peptidase-4 (DPP-4) slows degradation of endogenous glucagon-like peptide-1 (GLP-1) and thereby enhances and prolongs the action of the endogenous incretin hormones. The five available DPP-4 inhibitors, also known as 'gliptins' (sitagliptin, vildagliptin, saxagliptin, linagliptin, alogliptin), are small molecules used orally with similar overall clinical efficacy and safety profiles in patients with type 2 diabetes. The main differences between the five gliptins on the market include: potency, target selectivity, oral bioavailability, long or short half-life, high or low binding to plasma proteins, metabolism, presence of active or inactive metabolites, excretion routes, dosage adjustment for renal and liver insufficiency, and potential drug-drug interactions. On average, treatment with gliptins is expected to produce a mean glycated hemoglobin (HbA1c) decrease of 0.5%-0.8%, with about 40% of diabetic subjects at target for the HbA1c goal <7%. There are very few studies comparing DPP-4 inhibitors. Alogliptin as monotherapy or added to metformin, pioglitazone, glibenclamide, voglibose, or insulin therapy significantly improves glycemic control compared with placebo in adult or elderly patients with inadequately controlled type 2 diabetes. In the EXAMINE trial, alogliptin is being compared with placebo on cardiovascular outcomes in approximately 5,400 patients with type 2 diabetes. In clinical studies, DPP-4 inhibitors were generally safe and well tolerated. However, there are limited data on their tolerability, due to their relatively recent marketing approval. Alogliptin will be used most when avoidance of hypoglycemic events is paramount, such as in patients with congestive heart failure, renal failure, and liver disease, and in the elderly.

Association of musculoskeletal complaints and gliptin use: review of spontaneous reports

PURPOSE

Gliptins are new oral antidiabetic drugs that increase insulin levels through dipeptidyl peptidase-4 inhibition. Recently, the association of serious musculoskeletal (MSk) adverse effects with the gliptin use has been suggested. The aim is to describe and analyze the characteristics of spontaneous reports related to these adverse effects and gliptin use.

METHODS

All spontaneous reports with MSk disorders associated with gliptins gathered in the Spanish pharmacovigilance database until May 2012 were described and analyzed using a case/non-case method.

RESULTS

Gliptins were reported as the suspected drug in 332 cases: 208 involved sitagliptin, 115 vildagliptin, and nine saxagliptin. In 34 patients (10.2% of total reports with gliptins), MSk reactions were described (22 women [64.7%] and 12 men [35.3%]). Their mean age was 65.1 years; 41.2% were younger than 65 years. Only seven cases were serious, but the gliptin had to be withdrawn in 22 patients because of intolerance and/or persistence of MSk discomfort, and patients recovered after its discontinuation. A positive re-challenge was observed in two cases. In seven cases, the patients were on previous chronic treatment with statins, and began to present MSk complaints shortly after starting a gliptin. The reporting odds ratio (ROR) for myalgia and arthralgia were strongly associated with gliptin use (ROR 1.96 [95% CI 1.12-3.43], p < 0.05 and ROR 2.69 [95% CI 1.38-5.24], p < 0.05, respectively).

CONCLUSIONS

Musculoskeletal disorders are adverse reactions strongly associated with gliptins that, despite not being serious, may impair the treatment adherence in patients with type 2 diabetes. Future observational studies could confirm these findings.

The association of pancreatitis with antidiabetic drug use: gaining insight through the FDA pharmacovigilance database

In patients with diabetes, disease per se, co-morbidities and drugs, including novel agents acting on the incretin system, have all been associated with pancreatitis with controversial data. We investigated the publicly available FDA Adverse Event Reporting System (FDA_AERS) database to gain insight into the possible association between antidiabetic agents and pancreatitis. To this aim, a case/non-case method was retrospectively performed on the FDA_AERS database (2004-2009 period). Cases were defined as reports of pancreatitis according to the Medical Dictionary for Regulatory Activities (MedDRA) terminology. All other reports associated with antidiabetics were considered non-cases. The Reporting Odds Ratio (RORs), with corresponding 95% confidential interval (CI) and Mantel-Haenszel corrected P value, was calculated as a measure of disproportionality, with subsequent time-trend analysis. We retrieved 86,938 reports related to antidiabetics, corresponding to 159,226 drug-report combinations: 2,625 cases and 156,601 non-cases. Disproportionality was found only for exenatide (number of cases, 709; ROR, 1.76; 95% CI, 1.61-1.92; P MH < 0.001) and sitagliptin (128; 1.86; 1.54-2.24; <0.001). For exenatide, significant disproportionality appeared in the first quarter of 2008 (ROR, 1.24; 95% CI, 1.10-1.40; P MH < 0.001), soon after the FDA alert; for sitagliptin in the second quarter of 2008 (1.41; 1.05-1.90; 0.021). This temporal analysis found a striking influence of relevant FDA warnings on reporting of pancreatitis (the so-called notoriety bias) and is, therefore, recommended to avoid transforming a pharmacovigilance signal of alert automatically into an alarm. The precise quantification of the risk of pancreatitis associated with antidiabetics deserves assessment through specific disease-based registries.

Is incretin-based therapy ready for the care of hospitalized patients with type 2 diabetes?: Insulin therapy has proven itself and is considered the mainstay of treatment

Significant data suggest that overt hyperglycemia, either observed with or without a prior diagnosis of diabetes, contributes to an increase in mortality and morbidity in hospitalized patients. In this regard, goal-directed insulin therapy has remained as the standard of care for achieving and maintaining glycemic control in hospitalized patients with critical and noncritical illness. As such, protocols to assist in management of hyperglycemia in the inpatient setting have become commonplace in hospital settings. Clearly, insulin is a known entity, has been in clinical use for almost a century, and is effective. However, there are limitations to its use. Based on the observed mechanisms of action and efficacy, there has been a great interest in using incretin-based therapy with glucagon-like peptide-1 (GLP-1) receptor agonists instead of, or complementary to, an insulin-based approach to improve glycemic control in hospitalized, severely ill diabetic patients. To provide an understanding of both sides of the argument, we provide a discussion of this topic as part of this two-part point-counterpoint narrative. In the point narrative preceding the counterpoint narrative below, Drs. Schwartz and DeFronzo provide an opinion that now is the time to consider GLP-1 receptor agonists as a logical consideration for inpatient glycemic control. In the counterpoint narrative provided below, Drs. Umpierrez and Korytkowski provide a defense of insulin in the inpatient setting as the unquestioned gold standard for glycemic management in hospitalized settings.

The place of GLP-1-based therapy in diabetes management: differences between DPP-4 inhibitors and GLP-1 receptor agonists

Type 2 diabetes is a progressive disease characterized by the need for additional antidiabetic agents overtime to maintain a stable level of glycemic control. The discovery of the glucagon like peptide 1, 1 of the 2 major incretins, was pivotal to the development of novel therapies, which can be used in individuals with type 2 diabetes. Two classes of drugs, GLP-1 receptor agonists and dipeptidyl peptidase inhibitors, provide comparable or superior glycemic effects to previous antidiabetic agents without increasing side effects, such as weight gain and hypoglycemia. Therefore, they represent valuable additions to the current therapeutic options for type 2 diabetes.

Comparative safety and effectiveness of sitagliptin in patients with type 2 diabetes: retrospective population based cohort study

OBJECTIVE

To determine if the use of sitagliptin in newly treated patients with type 2 diabetes is associated with any changes in clinical outcomes.

DESIGN

Retrospective population based cohort study.

SETTING

Large national commercially insured US claims and integrated laboratory database.

PARTICIPANTS

Inception cohort of new users of oral antidiabetic drugs between 2004 and 2009 followed until death, termination of medical insurance, or December 31 2010.

MAIN OUTCOME MEASURE

Composite endpoint of all cause hospital admission and all cause mortality, assessed with time varying Cox proportional hazards regression after adjustment for demographics, clinical and laboratory data, pharmacy claims data, healthcare use, and time varying propensity scores.

RESULTS

The cohort included 72,738 new users of oral antidiabetic drugs (8032 (11%) used sitagliptin; 7293 (91%) were taking it in combination with other agents) followed for a total of 182,409 patient years. The mean age was 52 (SD 9) years, 54% (39,573) were men, 11% (8111) had ischemic heart disease, and 9% (6378) had diabetes related complications at the time their first antidiabetic drug was prescribed. 14,215 (20%) patients met the combined endpoint. Sitagliptin users showed similar rates of all cause hospital admission or mortality to patients not using sitagliptin (adjusted hazard ratio 0.98, 95% confidence interval 0.91 to 1.06), including patients with a history of ischemic heart disease (adjusted hazard ratio 1.10, 0.94 to 1.28) and those with estimated glomerular filtration rate below 60 mL/min (1.11, 0.88 to 1.41).

CONCLUSIONS

Sitagliptin use was not associated with an excess risk of all cause hospital admission or death compared with other glucose lowering agents among newly treated patients with type 2 diabetes. Most patients prescribed sitagliptin in this cohort were concordant with clinical practice guidelines, in that it was used as add-on treatment.

GLP-1 receptor agonists or DPP-4 inhibitors: how to guide the clinician?

Pharmacological treatment of type 2 diabetes has been enriched during recent years, with the launch of incretin therapies targeting glucagon-like peptide-1 (GLP-1). Such medications comprise either GLP-1 receptor agonists, with short (one or two daily injections: exenatide, liraglutide, lixisenatide) or long duration (one injection once weekly: extended-released exenatide, albiglutide, dulaglutide, taspoglutide); or oral compounds inhibiting dipeptidyl peptidase-4 (DPP-4), the enzyme that inactives GLP-1, also called gliptins (sitagliptin, vildagliptin, saxagliptin, linagliptin, alogliptin). Although both pharmacological approaches target GLP-1, important differences exist concerning the mode of administration (subcutaneous injection versus oral ingestion), the efficacy (better with GLP-1 agonists), the effects on body weight and systolic blood pressure (diminution with agonists versus neutrality with gliptins), the tolerance profile (nausea and possibly vomiting with agonists) and the cost (higher with GLP-1 receptor agonists). Both agents may exert favourable cardiovascular effects. Gliptins may represent a valuable alternative to a sulfonylurea or a glitazone after failure of monotherapy with metformin while GLP-1 receptor agonists may be considered as a good alternative to insulin (especially in obese patients) after failure of a dual oral therapy. However, this scheme is probably too restrictive and modalities of using incretins are numerous, in almost all stages of type 2 diabetes. Physicians may guide the pharmacological choice based on clinical characteristics, therapeutic goals and patient's preference.

Long-term safety of linagliptin monotherapy in Japanese patients with type 2 diabetes

AIMS

In a phase III study conducted among Japanese patients with type 2 diabetes mellitus (T2DM), linagliptin 5 and 10 mg showed clinically meaningful improvements in glycaemic parameters after 12 and 26 weeks compared with placebo and voglibose, respectively. This extension study assessed long-term tolerability of linagliptin over 52 weeks.

METHODS

Japanese patients with T2DM who completed either phase of a 12-week/26-week study comparing linagliptin monotherapy with placebo or voglibose were eligible to enrol. In the extension study, the comparator groups switched to linagliptin 5 or 10 mg, while the linagliptin groups maintained dosage.

RESULTS

In all, 540 patients received at least one dose of linagliptin 5 or 10 mg and 494 completed the extension. Long-term treatment with linagliptin was well tolerated; adverse events (AEs) of special interest and serious AEs occurred in small percentages of patients. Drug-related AEs occurred in 10.2 and 10.6% of patients in the linagliptin 5- and 10-mg groups, respectively, and discontinuations due to drug-related AEs occurred in 1.1 and 0.7%, respectively. Only one (0.4%) patient in each dose group experienced investigator-defined hypoglycaemia during the treatment period (both events were non-severe). Body weight was not clinically altered in either group. The glycated haemoglobin A1c profiles over time were similar with linagliptin 5 and 10 mg.

CONCLUSIONS

These findings provide evidence for the safety and tolerability of oral linagliptin at either 5 or 10 mg for up to 52 weeks for the treatment of Japanese patients with T2DM, without clinically relevant increase in the risk of hypoglycaemia or weight gain.

Longer term safety of dipeptidyl peptidase-4 inhibitors in patients with type 2 diabetes mellitus: systematic review and meta-analysis

Dipeptidyl peptidase-4 (DPP-4) inhibitors are oral antidiabetic agents that hold the potential of slowing the progress of type 2 diabetes mellitus. Their long-term safety is still a subject of debate. A systematic review of randomized, controlled trials was undertaken to comprehensively profile the safety of chronic treatment of type 2 diabetes mellitus with DPP-4 inhibitors. We searched data sources including MEDLINE, CENTRAL, publishers' and manufacturers' databases. Eligible trials were double-blind, randomized, placebo or active-controlled trials with ≥18 weeks duration in patients with type 2 diabetes reporting safety outcomes. Meta-analysis was performed separately for trials in which the control group received placebo (44 studies), another gliptin (3 studies) and any other antidiabetic drug (20 studies). Risk ratios with 95% confidence intervals were computed using a Mantel-Haenszel fixed-effect model for general safety outcomes, hypoglycaemia and adverse events by system organ class. Of 307 publications retrieved, 67 randomized, controlled trials met the eligibility criteria and were included in this review (4 alogliptin, 8 linagliptin, 8 saxagliptin, 20 sitagliptin, and 27 vildagliptin trials). Adverse events with gliptin treatment were at placebo level (relative risk (RR) 1.02 [0.99, 1.04]). No increased risk of infections was detectable (RR 0.98 [0.93, 1.05] compared to placebo and 1.02 [0.97, 1.07] compared to other antidiabetic drugs). Asthenia (RR 1.57 [1.09, 2.27]) as well as cardiac (RR 1.37 [1.00, 1.89]) and vascular disorders (RR 1.74 [1.05, 2.86] for linagliptin) emerged as adverse events associated with DPP-4 inhibitor treatment. The risk of hypoglycaemia was low with DPP-4 inhibitor treatment (RR 0.92 [0.74, 1.15] compared to placebo, RR 0.20 [0.17, 0.24] compared to sulphonylureas) in the absence of sulphonylurea or insulin co-therapy, but significantly elevated for combination therapy of sulphonylurea or insulin with sitagliptin or linagliptin (RR 1.86 [1.46, 2.37] compared to placebo). A large body of data supports the long-term safety of gliptin treatment and refutes an increased risk of infections. Further research is needed to clarify a possible link to asthenia, cardiac and vascular events. For combination therapy with insulin or insulin secretagogues, a careful choice of the agent used may limit the risk of hypoglycaemia.

Recent advances in incretin-based therapies

The global burden of type 2 diabetes is growing. Traditional therapies are suboptimal and there is a clear unmet need for treatments that offer effective glucose control while addressing the comorbid factors associated with diabetes, such as obesity and risk of cardiovascular disease, without the fear of hypoglycaemia. Glucagon-like peptide-1 receptor agonists and dipeptidyl peptidase-4 inhibitors offer a novel way of reducing hyperglycaemia by targeting the incretin system. This review provides an overview of the development of incretin-based therapies and explains their differing modes of action compared with traditional interventions. A comparison of the clinical profiles of current glucagon-like peptide-1 receptor agonists [liraglutide and exenatide (twice-daily and once-weekly)] and dipeptidyl peptidase-4 inhibitors (sitagliptin, saxagliptin, vildagliptin and linagliptin) is performed alongside a discussion of the placement of incretin-based therapies in treatment guidelines. Further improvements in this class are expected, and we will examine some of the novel glucagon-like peptide-1 receptor agonists and dipeptidyl peptidase-4 inhibitors currently under development.

Incretin therapy and its effect on body weight in patients with diabetes

Glucagon-like peptide 1 (GLP-1) analogues and dipeptidyl peptidase-4 (DPP-4) inhibitors are two classes of treatments for type 2 diabetes, which enhance the well-known 'incretin effect' of increased insulin secretion in response to food intake. This concise review introduces both types of incretin-based therapies and focuses on the extra-pancreatic effect of GLP-1 on body weight. As well as improving glycaemic control in subjects with type 2 diabetes, these treatments have the additional benefits of improving weight management in these patients, with GLP-1 receptor agonists causing weight loss and DPP-4 inhibitors being weight neutral.

Linagliptin for type 2 diabetes mellitus: a review of the pivotal clinical trials

Patients with type 2 diabetes mellitus (T2DM) frequently require multiple therapies to effectively control hyperglycemia, and many new agents for glucose control have been developed over the past few decades. Linagliptin is a recently approved oral antidiabetic drug that acts by inhibiting the enzyme dipeptidyl peptidase-4 (DPP-4). Unlike other DPP-4 inhibitors, linagliptin is excreted chiefly via the enterohepatic system, and can be used without dose adjustment in patients with renal or hepatic impairment. Linagliptin was approved by the US Food and Drug Administration based on a large development program, including four pivotal trials in patients with T2DM, assessing the efficacy and safety of linagliptin when used as monotherapy or in combination with other oral antidiabetes drugs. Linagliptin was associated with significant improvements in glycosylated hemoglobin, fasting plasma glucose and postprandial glucose, and more patients receiving linagliptin showed meaningful improvements and achieved targets for glycosylated hemoglobin. Linagliptin was well tolerated, with an adverse event profile similar to that of placebo, and low rates of hypoglycemic events. Taken together, the pivotal trials confirm linagliptin is effective and safe in patients with T2DM: the convenience of oral dosing with no requirement for dose adjustment in patients with renal or hepatic impairment make linagliptin a valuable option when considering therapies for patients with T2DM.

Long-term safety and efficacy of linagliptin as monotherapy or in combination with other oral glucose-lowering agents in 2121 subjects with type 2 diabetes: up to 2 years exposure in 24-week phase III trials followed by a 78-week open-label extension

Aim:  The aim of this study was to evaluate the long-term safety, tolerability and efficacy of the dipeptidyl peptidase-4 inhibitor linagliptin given either alone or in combination with other oral glucose-lowering agents in persons with type 2 diabetes. Methods:  A 78-week open-label extension study evaluated subjects who participated in one of four preceding 24-week, randomised, double-blind, placebo-controlled parent trials and who received linagliptin, linagliptin + metformin, linagliptin + metformin + a sulphonylurea or linagliptin + pioglitazone (all with linagliptin administered orally once daily). Individuals receiving one of these treatments during a previous trial continued the same treatment (n = 1532) for up to a total of 102 weeks, whereas those previously receiving placebo were switched to linagliptin (n = 589). All 2121 participants received at least one dose of the trial medication and were included in the primary safety analysis. Results:  In subjects previously receiving active treatment, the glycosylated haemoglobin A(1c) reduction achieved during the 24-week parent trials was sustained through the 78-week extension period (change from baseline to week 102: -0.8%). Drug-related adverse events were experienced by 14.3% of participants. Hypoglycaemia occurred in 13.9% of participants and was similar between those previously receiving treatment (13.6%) and those switching from placebo to linagliptin (14.6%). Hypoglycaemia occurred most frequently with the use of metformin + a sulphonylurea background therapy (11%). Overall, no clinically relevant changes in body weight were observed. Conclusion:  Long-term treatment with linagliptin was well tolerated with no change in the safety profile observed during the extension study. Sustained long-term glycaemic control was maintained for up to 102 weeks with either linagliptin monotherapy or linagliptin in combination with other oral glucose-lowering agents.

The effect of linagliptin on glycaemic control and tolerability in patients with type 2 diabetes mellitus: a systematic review and meta-analysis

AIM

Linagliptin is a new dipeptidyl peptidase-4 inhibitor recently approved for use in the USA. The objective of this systematic review and meta-analysis was to assess effect of linagliptin on glycaemic control, biomarkers and incidence of adverse events (AEs) in patients with type 2 diabetes mellitus.

METHODS

Five published and four unpublished randomized, clinical trials were identified from multiple databases. Qualitative assessments and quantitative analyses were performed.

RESULTS

Nine studies included 4246 participants with 53% men, 59.4% Caucasians, 38.7% Asians, and age range 45-69 years. Linagliptin was given as monotherapy (vs. placebo) or combined with metformin (vs. metformin + placebo), sulphonylurea (vs. sulphonylurea + placebo) or pioglitazone (vs. pioglitazone + placebo). Linagliptin 5 mg/day for 12-24 weeks, significantly reduced haemoglobin A1c (HbA1c) (-0.63%, p < 0.00001), fasting plasma glucose (FPG) (-1.01 mmol/l, p < 0.00001) and improved disposition index (DI, product of insulin sensitivity and acute insulin secretion) (p = 0.0001). Linagliptin monotherapy was not more effective than metformin at reducing HbA1c or FPG. Similar proportion of patients in linagliptin and placebo groups reported AEs including upper respiratory tract infections, headaches, nausea, hypertension and back pain.

CONCLUSIONS

Linagliptin was associated with modest but significant reduction in HbA1c and FPG and improved DI after 12-24 weeks. Patients who would probably benefit most are those with HbA1c <9%, already on an active agent, compliant with weight reduction strategies, and can recognize and manage hypoglycaemia, fluid retention and upper respiratory tract infections. Long-term studies are needed to determine durability of response, incidence of microvascular and macrovacular complications, cost-effectiveness and safety.