Predictors of response to dipeptidyl peptidase-4 inhibitors: evidence from randomized clinical trials

Endogenous GLP-1 levels play an important role in determining the efficacy of DPP-IV Inhibitors in both prediabetes and type 2 diabetes

BACKGROUND

In contrast to Western population, glucagon-like peptide-1 (GLP-1) levels are preserved in some East Asian population with type 2 diabetes (T2D), explaining why dipeptidyl peptidase-IV (DPP-IV) inhibitors are more effective in East Asians. We assessed whether differences in endogenous GLP-1 levels resulted in different treatment responses to DPP-IV inhibitors in prediabetes and T2D.

METHODS

A prospective 12-week study using linagliptin 5mg once daily in 50 subjects (28 prediabetes and 22 T2D) who were stratified into high versus low fasting GLP-1 groups. A 75-g oral glucose tolerance test (OGTT) was performed at week 0 and 12. Primary outcomes were changes in HbA1c, fasting and post-OGTT glucose after 12 weeks. Secondary outcomes included changes in insulin resistance and beta cell function indices.

RESULTS

There was a greater HbA1c reduction in subjects with high GLP-1 compared to low GLP-1 levels in both the prediabetes and T2D populations [least-squares mean (LS-mean) change of -0.33% vs. -0.11% and -1.48% vs. -0.90% respectively)]. Linagliptin significantly reduced glucose excursion by 18% in high GLP-1 compared with 8% in low GLP-1 prediabetes groups. The reduction in glucose excursion was greater in high GLP-1 compared to low GLP-1 T2D by 30% and 21% respectively. There were significant LS-mean between-group differences in fasting glucose (-0.95 mmol/L), 2-hour glucose post-OGTT (-2.4 mmol/L) in the high GLP-1 T2D group. Improvement in insulin resistance indices were seen in the high GLP-1 T2D group while high GLP-1 prediabetes group demonstrated improvement in beta cell function indices. No incidence of hypoglycemia was reported.

CONCLUSIONS

Linagliptin resulted in a greater HbA1c reduction in the high GLP-1 prediabetes and T2D compared to low GLP-1 groups. Endogenous GLP-1 level play an important role in determining the efficacy of DPP-IV inhibitors irrespective of the abnormal glucose tolerance states.

Increasing Age Associated with Higher Dipeptidyl Peptidase-4 Inhibition Rate Is a Predictive Factor for Efficacy of Dipeptidyl Peptidase-4 Inhibitors

BACKGROUND

It is not known which type 2 diabetes mellitus (T2DM) patients would most benefit from dipeptidyl peptidase-4 (DPP-4) inhibitor treatment. We aimed to investigate the predictors of response to DPP-4 inhibitors considering degree of DPP-4 inhibition.

METHODS

This study is a post hoc analysis of a 24-week, randomized, double-blind, phase III trial that compared the efficacy and safety of a DPP-4 inhibitor (gemigliptin vs. sitagliptin) in patients with T2DM. Subjects were classified into tertiles of T1 <65.26%, T2=65.26%-76.35%, and T3 ≥76.35% by DPP-4 inhibition. We analyzed the change from baseline in glycosylated hemoglobin (HbA1c) according to DPP-4 inhibition with multiple linear regression adjusting for age, ethnicity, body mass index, baseline HbA1c, and DPP-4 activity at baseline.

RESULTS

The mean age was greater in the high tertile group compared with the low tertile group (T1: 49.8±8.3 vs. T2: 53.1±10.5 vs. T3: 55.3±9.5, P<0.001) of DPP-4 inhibition. Although HbA1c at baseline was not different among tertiles of DPP-4 inhibition (P=0.398), HbA1c after 24-week treatment was lower in the higher tertile compares to the lower tertile (T1: 7.30%±0.88% vs. T2: 7.12%±0.78% vs. T3: 7.00%±0.78%, P=0.021). In multiple regression analysis, DPP-4 enzyme inhibition rate was not a significant determent for HbA1c reduction due to age. In subgroup analysis by tertile of DPP-4 inhibition, age was the only significant predictor and only in the highest tertile (R2=0.281, B=-0.014, P=0.024).

CONCLUSION

This study showed that HbA1c reduction by DPP-4 inhibitor was associated with increasing age, and this association was linked with higher DPP-4 inhibition.

Dipeptidyl peptidase-4 inhibitor, anagliptin, alters hepatic insulin clearance in relation to the glycemic status in Japanese individuals with type 2 diabetes

AIMS/INTRODUCTION

This study investigated the impact of the dipeptidyl peptidase-4 inhibitor, anagliptin, on hepatic insulin clearance (HIC) in Japanese type 2 diabetes patients and explored its relationship to glycemic status.

MATERIALS AND METHODS

Data on 765 participants in anagliptin phase 2 and 3 studies were analyzed. Adjusted changes in variables during 12 weeks of anagliptin therapy were compared with a placebo. HIC was calculated as the ratio, C-peptide area under the curve 0-120 min to insulin area under the curve 0-120 min, after a meal tolerance test. To explore the effects of baseline HIC levels on variables, participants receiving anagliptin were divided according to quartiles of baseline HIC. Furthermore, multivariate analysis investigated the association between baseline HIC levels and glycemic status.

RESULTS

Anagliptin significantly reduced glycosylated hemoglobin levels (P < 0.001 vs placebo) and HIC levels (P < 0.01). Longer duration of diabetes, lower body mass index, higher glycosylated hemoglobin and lower insulin secretion capacity were observed with increases in baseline HIC levels. Improvements in glycosylated hemoglobin, glycoalbumin and 1,5-anhydroglucitol levels were greater in the relatively higher HIC group (baseline HIC levels ≥median) than in the lower HIC group (

CONCLUSIONS

Anagliptin affected HIC levels according to HIC baseline levels. Higher baseline HIC values might result in improved hyperglycemia through reduced HIC.

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Key Words

• Dipeptidyl peptidase-4 inhibitor
• Hepatic insulin clearance
• Meal tolerance test

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MESH Headings

• Aged
• Asian People
• Diabetes Mellitus, Type 2/drug therapy
• Diabetes Mellitus, Type 2/metabolism
• Dipeptidyl-Peptidase IV Inhibitors/pharmacology
• Dipeptidyl-Peptidase IV Inhibitors/therapeutic use
• Double-Blind Method
• Female
• Humans
• Insulin/metabolism
• Liver/metabolism
• Male
• Middle Aged
• Pyrimidines/pharmacology
• Pyrimidines/therapeutic use

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Grants

• Sanwa Kagaku Kenkyusho Co., Ltd.
• Kowa Co., Ltd

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Affiliation(s)

Takahiro Abe Department of Hematology, Endocrinology and MetabolismNiigata University Faculty of MedicineNiigataJapan
Yasuhiro Matsubayashi Department of Hematology, Endocrinology and MetabolismNiigata University Faculty of MedicineNiigataJapan
Sayaka Muragishi Kowa Co., Ltd.TokyoJapan
Akihiro Yoshida Department of Hematology, Endocrinology and MetabolismNiigata University Faculty of MedicineNiigataJapan Kowa Co., Ltd.TokyoJapan
Hideki Suganami Kowa Co., Ltd.TokyoJapan
Kenichi Furusawa Sanwa Kagaku Kenkyusho Co., Ltd.NagoyaJapan
Kazuya Fujihara Department of Hematology, Endocrinology and MetabolismNiigata University Faculty of MedicineNiigataJapan
Shiro Tanaka Department of Clinical BiostatisticsGraduate School of Medicine Kyoto UniversityKyotoJapan
Kohei Kaku Kawasaki Medical SchoolOkayamaJapan
Hirohito Sone Department of Hematology, Endocrinology and MetabolismNiigata University Faculty of MedicineNiigataJapan

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Glucose-lowering action through targeting islet dysfunction in type 2 diabetes: Focus on dipeptidyl peptidase-4 inhibition

Dipeptidyl peptidase-4 (DPP-4) inhibition is a glucose-lowering medication for type 2 diabetes. It works through stimulation of insulin secretion and inhibition of glucagon secretion in a glucose-dependent manner, resulting in lowered fasting and postprandial glycemia with low risk of hypoglycemia. As impaired insulin secretion and augmented glucagon secretion are key factors underlying hyperglycemia in type 2 diabetes, DPP-4 inhibition represents a therapy that targets the underlying mechanisms of the disease. If insufficient in monotherapy, it can preferably be used in combination with metformin, which targets insulin resistance, and also in combination with sodium-glucose cotransporter 2 inhibition, thiazolidinediones and insulin, which target other mechanisms. In individuals of East Asian origin, islet dysfunction is of particular importance for the development of type 2 diabetes. Consequently, it has been shown in several studies that DPP-4 is efficient in these populations. This mini-review highlights the islet mechanisms of DPP-4 inhibition, islet dysfunction as a key factor for hyperglycemia in type 2 diabetes and that, consequently, DPP-4 is of particular value in populations where islet dysfunction is central, such as in individuals of East Asian origin.

Efficacy and Safety of Ertugliflozin in Patients with Overweight and Obesity with Type 2 Diabetes Mellitus

OBJECTIVE

This study aimed to evaluate ertugliflozin in patients with overweight and obesity with type 2 diabetes mellitus.

METHODS

Data from three placebo-controlled, randomized, Phase 3 studies were pooled. Patients with baseline BMI ≥ 25 (1,377/1,544; 89%) were assessed with a stratification by BMI subgroup.

RESULTS

At week 26, reductions from baseline in glycated hemoglobin A1c (HbA1c), fasting plasma glucose, body weight (BW), and systolic blood pressure (SBP) were greater with ertugliflozin versus placebo. For placebo, ertugliflozin 5 mg, and ertugliflozin 15 mg, respectively, least squares mean change was 0.1%, -0.8%, and -0.9% for HbA1c and -1.2 kg, -3.1 kg, and -3.2 kg for BW. HbA1c reductions were consistent across BMI subgroups. For ertugliflozin 5 mg and 15 mg, least squares mean change (placebo adjusted) in absolute BW was -1.4 kg and -1.2 kg for BMI 25 to < 30, -1.8 kg and -1.9 kg for BMI 30 to < 35, and -2.5 kg and -2.9 kg for BMI ≥ 35. Percent BW changes were similar across BMI subgroups. Incidence of adverse events was 52.5%, 44.6%, and 50.1% with placebo, ertugliflozin 5 mg, and ertugliflozin 15 mg, respectively.

CONCLUSIONS

Meaningful reductions in HbA1c, fasting plasma glucose, BW, and SBP were observed with ertugliflozin in patients with overweight and obesity with type 2 diabetes mellitus. Ertugliflozin improved HbA1c and SBP and reduced BW across BMI subgroups. Ertugliflozin was generally well tolerated.

Risk of any hypoglycaemia with newer antihyperglycaemic agents in patients with type 2 diabetes: A systematic review and meta-analysis

OBJECTIVES

For patients with type 2 diabetes, newer antihyperglycaemic agents (AHA), including the dipeptidyl peptidase IV inhibitors (DPP4i), glucagon-like peptide-1 receptor agonists (GLP1RA) and sodium glucose co-transporter 2 inhibitors (SGLT2i) offer a lower risk of hypoglycaemia relative to sulfonylurea or insulin. However, it is not clear how AHA compare to placebo on risk of any hypoglycaemia. This study evaluates the risk of any and severe hypoglycaemia with AHA and metformin relative to placebo.

DESIGN

A systematic review and meta-analysis was conducted of randomized, placebo-controlled trials ≥12 weeks in duration. MEDLINE, Embase and the Cochrane Library were searched up to April 16, 2019. Studies allowing use of other diabetes medications were excluded. Mantel-Haenszel risk ratio with 95% confidence intervals were used to pool estimates based on class of AHA and number of concomitant therapies used.

PATIENTS

Eligible studies enrolled patients with type 2 diabetes ≥18 years of age.

RESULTS

144 studies met our inclusion criteria. Any hypoglycaemia was not increased with AHA when used as monotherapy (DPP4i (RR 1.12; 95% CI 0.81-1.56), GLP1RA (1.77; 0.91-3.46), SGLT2i (1.34; 0.83-2.15)), or as add-on to metformin (DPP4i (0.95; 0.67-1.35), GLP1RA (1.24; 0.80-1.91), SGLT2i (1.29; 0.91-1.83)) or as triple therapy (1.13; 0.67-1.91). However, metformin monotherapy (1.73; 1.02-2.94) and dual therapy initiation (3.56; 1.79-7.10) was associated with an increased risk of any hypoglycaemia. Severe hypoglycaemia was rare not increased for any comparisons.

CONCLUSIONS

Metformin and the simultaneous initiation of dual therapy, but not AHA used alone or as single add-on combination therapy, was associated with an increased risk of any hypoglycaemia relative to placebo.

Development of a 13C Stable Isotope Assay for Dipeptidyl Peptidase-4 Enzyme Activity A New Breath Test for Dipeptidyl Peptidase Activity

Dipeptidyl peptidase-4 inhibitors (DPP4i) are a class of orally available, small molecule inhibitors for the management of Type-II diabetes. A rapid, real-time, functional breath test for DPP4 enzyme activity could help to define DPP4i efficacy in patients that are refractory to treatment. We aimed to develop a selective, non-invasive, stable-isotope ¹³C-breath test for DPP4. In vitro experiments were performed using high (Caco-2) and low (HeLa) DPP4 expressing cells. DPP gene expression was determined in cell lines by qRT-PCR. A DPP4 selective ¹³C-tripeptide was added to cells in the presence and absence of the DPP4 inhibitor Sitagliptin. Gas samples were collected from the cell headspace and ¹³CO₂ content quantified by isotope ratio mass spectrometry (IRMS). DPP4 was highly expressed in Caco-2 cells compared to HeLa cells and using the ¹³C-tripeptide, we detected a high ¹³CO₂ signal from Caco2 cells. Addition of Sitaglitpin to Caco2 cells significantly inhibited this ¹³CO₂ signal. ¹³C-assay DPP4 activity correlated positively with the enzyme activity detected using a colorimetric substrate. We have developed a selective, non-invasive, ¹³C-assay for DPP4 that could have broad translational applications in diabetes and gastrointestinal disease.

Precision Medicine in Type 2 Diabetes: Clinical Markers of Insulin Resistance Are Associated With Altered Short- and Long-term Glycemic Response to DPP-4 Inhibitor Therapy

OBJECTIVE

A precision approach to type 2 diabetes therapy would aim to target treatment according to patient characteristics. We examined if measures of insulin resistance and secretion were associated with glycemic response to dipeptidyl peptidase 4 (DPP-4) inhibitor therapy.

RESEARCH DESIGN AND METHODS

We evaluated whether markers of insulin resistance and insulin secretion were associated with 6-month glycemic response in a prospective study of noninsulin-treated participants starting DPP-4 inhibitor therapy (Predicting Response to Incretin Based Agents [PRIBA] study; n = 254), with replication for routinely available markers in U.K. electronic health care records (Clinical Practice Research Datalink [CPRD]; n = 23,001). In CPRD, we evaluated associations between baseline markers and 3-year durability of response. To test the specificity of findings, we repeated analyses for glucagon-like peptide 1 (GLP-1) receptor agonists (PRIBA, n = 339; CPRD, n = 4,464).

RESULTS

In PRIBA, markers of higher insulin resistance (higher fasting C-peptide [P = 0.03], HOMA2 insulin resistance [P = 0.01], and triglycerides [P < 0.01]) were associated with reduced 6-month HbA_1c response to DPP-4 inhibitors. In CPRD, higher triglycerides and BMI were associated with reduced HbA_1c response (both P < 0.01). A subgroup defined by obesity (BMI ≥30 kg/m²) and high triglycerides (≥2.3 mmol/L) had reduced 6-month response in both data sets (PRIBA HbA_1c reduction 5.3 [95% CI 1.8, 8.6] mmol/mol [0.5%] [obese and high triglycerides] vs. 11.3 [8.4, 14.1] mmol/mol [1.0%] [nonobese and normal triglycerides]; P = 0.01). In CPRD, the obese, high- triglycerides subgroup also had less durable response (hazard ratio 1.28 [1.16, 1.41]; P < 0.001). There was no association between markers of insulin resistance and response to GLP-1 receptor agonists.

CONCLUSIONS

Markers of higher insulin resistance are consistently associated with reduced glycemic response to DPP-4 inhibitors. This finding provides a starting point for the application of a precision diabetes approach to DPP-4 inhibitor therapy.

Pharmacogenetics of oral antidiabetic therapy

Type 2 diabetes prevalence is still on the rise worldwide. Antidiabetic drugs are widely prescribed to patients with Type 2 diabetes. Most patients start with metformin which is mostly well tolerated. However, a high percentage of patients fail to achieve glycemic control. The effectiveness of metformin as well as most other antidiabetic drugs depends among other factors on interindividual genetic differences that are up to now ignored in the treatment of Type 2 diabetes. Interestingly, many genes influencing the effectiveness of antidiabetic drugs are Type 2 diabetes risk genes making matters worse. Here, we shed light on these interindividual genetic differences.

DPP4 inhibitors and cardiovascular outcomes: safety on heart failure

Diabetes is an important risk factor for cardiovascular disease. However, clinical data suggests intensive glycemic control significantly increase rather than decrease cardiovascular mortality, which is largely due to the fact that a majority of oral anti-diabetic drugs have adverse cardiovascular effect. There are several large-scale clinical trials evaluating the cardiovascular safety of DPP4 inhibitors, a novel class of oral anti-diabetic medications, which have been recently completed. They were proven to be safe with regard to cardiovascular outcomes. However, concerns on the safety of heart failure have been raised as the SAVOR-TIMI 53 trial reported a 27% increase in the risk for heart failure hospitalization in diabetic patients treated with DPP4 inhibitor saxagliptin. In this review, we will discuss recent advances in the heart failure effects of DPP4 inhibition and GLP-1 agonism.

Safety and efficacy of long-term treatment with teneligliptin: Interim analysis of a post-marketing surveillance of more than 10,000 Japanese patients with type 2 diabetes mellitus

BACKGROUND

This post-marketing surveillance examined the safety and efficacy of long-term teneligliptin therapy in Japanese patients.

RESEARCH DESIGN AND METHODS

We report interim results (cut-off date: 28 June 2017) of a 3-year PMS undertaken in subjects with type 2 diabetes mellitus (T2DM). Survey items included demographics, treatments, adverse drug reactions (ADRs), and laboratory variables. A subgroup analysis was also performed across three age groups (<65 years; 65 to <75 years; ≥75 years). Main outcome measures were incidence of ADRs, laboratory variables, and change in glycated hemoglobin (HbA1c) from baseline over time.

RESULTS

Of 11,677 patients registered, data from 10,532 patients (6,338 males/4,194 females) were analyzed for the safety analysis set; the median administration period was 731 days. Overall, ADRs and serious ADRs were reported in 364 (3.46%) and 91 patients (0.86%), respectively. The most common ADRs were all hypoglycemia (0.32%), constipation (0.27%), and hepatic function abnormal (0.24%). No change in mean body weight occurred, and a reduction in mean HbA1c was observed until 2 years. The safety and efficacy profiles did not differ markedly among the three age groups.

CONCLUSIONS

These interim results show that teneligliptin was well tolerated and improved hyperglycemia in Japanese patients with T2DM in clinical practice.

Comparison of the Effects of Teneligliptin and Sitagliptin, Two Dipeptidyl Peptidase 4 Inhibitors with Different Half-Lives, on Glucose Fluctuation and Glucagon-Like Peptide-1 in Type 2 Diabetes Mellitus

Our purpose was to determine the effects of teneligliptin and sitagliptin, two dipeptidyl peptidase 4 inhibitors (DPP4-Is) with different half-lives, on glycemic variability and glucagon-like peptide-1 (GLP-1) levels in Japanese patients with type 2 diabetes mellitus (T2DM). The study subjects were 14 drug-naïve patients with T2DM who were allocated to either a 20 mg/day teneligliptin group (n = 7) or a 50 mg/day sitagliptin group (n = 7) for 7 days, then switched to the other treatment for another 7 days. Meal tolerance tests were performed at the time of no treatment, and after treatment with each DPP4-Is at supper. We evaluated the effects of each drug on glucose fluctuation using continuous glucose monitoring (CGM). There was no significant difference between the two groups in the primary endpoint (maximum glucose level after supper), nor in the secondary endpoint: area under the curve (AUC) for plasma glucose (≥140 mg/dl) after supper (18:00 - 24:00). Teneligliptin significantly improved the AUC for plasma glucose (≥140 mg/dl) after supper (20:00-24:00) (P = 0.048), and also significantly increased the GLP-1 level at 30 minutes after the meal load (P = 0.030). No serious adverse effects were noted in either group, apart from a few episodes of asymptomatic hypoglycemia. A daily dose of teneligliptin improved the AUC for plasma glucose at 20:00 to 24:00 (≥140 mg/dl) after the meal tolerance test, and also significantly increased the levels of activated GLP-1 after the test meal.

DPP4 gene variation affects GLP-1 secretion, insulin secretion, and glucose tolerance in humans with high body adiposity

Objective

Dipeptidyl-peptidase 4 (DPP-4) cleaves and inactivates the insulinotropic hormones glucagon-like peptide 1 (GLP-1) and gastric inhibitory polypeptide, collectively termed incretins. DPP-4 inhibitors entered clinical practice as approved therapeutics for type-2 diabetes in 2006. However, inter-individual variance in the responsiveness to DPP-4 inhibitors was reported. Thus, we asked whether genetic variation in the DPP4 gene affects incretin levels, insulin secretion, and glucose tolerance in participants of the TÜbingen Family study for type-2 diabetes (TÜF).

Research design and methods

Fourteen common (minor allele frequencies ≥0.05) DPP4 tagging single nucleotide polymorphisms (SNPs) were genotyped in 1,976 non-diabetic TÜF participants characterized by oral glucose tolerance tests and bioimpedance measurements. In a subgroup of 168 subjects, plasma incretin levels were determined.

Results

We identified a variant, i.e., SNP rs6741949, in intron 2 of the DPP4 gene that, after correction for multiple comparisons and appropriate adjustment, revealed a significant genotype-body fat interaction effect on glucose-stimulated plasma GLP-1 levels (p = 0.0021). Notably, no genotype-BMI interaction effects were detected (p = 0.8). After stratification for body fat content, the SNP negatively affected glucose-stimulated GLP-1 levels (p = 0.0229), insulin secretion (p = 0.0061), and glucose tolerance (p = 0.0208) in subjects with high body fat content only.

Conclusions

A common variant, i.e., SNP rs6741949, in the DPP4 gene interacts with body adiposity and negatively affects glucose-stimulated GLP-1 levels, insulin secretion, and glucose tolerance. Whether this SNP underlies the reported inter-individual variance in responsiveness to DPP-4 inhibitors, at least in subjects with high body fat content, remains to be shown.

Predictive Factors for the Therapeutic Response to Concomitant Treatment with DPP-4 Inhibitors in Type 2 Diabetes with Short-Term Follow-Up

Objectives To evaluate the efficacy and predictive factors of Dipeptidyl peptidase-4 (DPP-4) inhibitors in type 2 diabetes mellitus (T2DM) patients who were not well controlled with other oral antidiabetic drugs or insulin in real clinical practice. Methods From December 2012 to January 2014, retrospective longitudinal observation study was conducted for patients with T2DM who were not reached a glycemic target (glycated hemoglobin [HbA1c] &gt; 6.5%) with other oral antidiabetic drugs or insulins. Type 1 diabetes or other types of diabetes were excluded. Responders were eligible with decreased HbA1c from baseline for more than 5% during follow up period. Results Of total 135 T2DM patients having an average 9.0 months follow-up period, 84 (62.2%) of patients were responder to DPP-4 inhibitors. After concomitant treatment with DPP-4 inhibitors, patients had a mean decrease in HbA1c of 0.69 ± 1.3%, fasting plasma glucose of 13 ± 52 ㎎/㎗, and postprandial plasma glucose of 29 ± 85 ㎎/㎗ from baseline (all P&lt; 0.05). Independent predictive factor for an improvement of glycemic control with DPP-4 inhibitors was higher baseline HbA1c (odds ratio 2.07 with 95% confidence interval 1.15–3.72) compared with non-responders. Conclusions A clinical meaningful improvement in glycemic control was seen when DPP-4 inhibitors were added to other anti-diabetic medications in patients with T2DM regardless of age, duration of T2DM, type of combination treatment regimen. Patients who had higher HbA1c were more easily respond to DPP-4 inhibitors treatment in short-term follow-up period.

Baseline Body Mass Index and the Efficacy of Hypoglycemic Treatment in Type 2 Diabetes: A Meta-Analysis

AIM

The aim of this study is to compare the effects of hypoglycemic treatments in groups of patients categorized according to the mean baseline body mass indexes (BMIs).

METHODS

Studies were identified by a literature search and all the studies were double blind, placebo-controlled randomized trials in type 2 diabetes patients; study length of ≥12 weeks with the efficacy evaluated by changes in HbA1c from baseline in groups. The electronic search was first conducted in January 2015 and repeated in June 2015.

RESULTS

227 studies were included. Treatment with sulfonylureas was compared with placebo in overweight patients and resulted in a significantly greater change in the HbA1c levels (weighted mean difference (WMD), -1.39%) compared to obese patients (WMD, -0.77%)(p<0.05). Treatment with metformin in overweight patients resulted in a comparable change in the HbA1c levels (WMD, -0.99%) compared to obese patients (WMD, -1.06%)(p>0.05). Treatment with alpha glucosidase inhibitors in normal weight patients was associated with a HbA1c change (WMD, -0.94%) that was comparable that in overweight (WMD, -0.72%) and obese patients (WMD, -0.56%)(p>0.05). Treatment with thiazolidinediones in normal weight patients was associated with a HbA1c change (WMD, -1.04%) that was comparable with that in overweight (WMD, -1.02%) and obese patients (WMD, -0.88%)(p>0.05). Treatment with DPP-4 inhibitors in normal weight patients was associated with a HbA1c change (WMD, -0.93%) that was comparable with that in overweight (WMD, -0.66%) and obese patients (WMD, -0.61%)(p>0.05). In total, of the seven hypoglycemic agents, regression analysis indicated that the mean baseline BMI was not associated with the mean HbA1c changes from baseline.

CONCLUSION

In each kind of hypoglycemic therapy in type 2 diabetes, the baseline BMI was not associated with the efficacy of HbA1c changes from baseline.

A genetic variant in GLP1R is associated with response to DPP-4 inhibitors in patients with type 2 diabetes

Incretin hormone-based therapy in type 2 diabetes has been widely used, and dipepdityl peptidase-4 (DPP-4) inhibitors, which prevent incretin degradation, have become popular oral hypoglycemic agents. The efficacy of DPP-4 inhibitors varies from individuals, and factors determining responses to DPP-4 inhibitors have not been fully established. We aimed to investigate whether genetic variations in glucagon-like peptide (GLP-1) receptor are associated with responses to DPP-4 inhibitors in patients with type 2 diabetes.Genetic variations of rs3765467 in GLP-1 receptor were explored in 246 patients with type 2 diabetes who received DPP-4 inhibitors treatment for 24 weeks in addition to previous medication. Patients with glycated hemoglobin (HbA1c) > 7% and who were naive to any DPP-4 inhibitors were enrolled. Responders were defined as those who showed a > 10% reduction in HbA1c after DPP-4 inhibitor treatment.DPP-4 inhibitors improved glycemic parameters and lipid profiles. Compared to the major genotype (GG), a larger proportion of patients with the minor allele genotype (GA/AA) were responders (P = 0.018), and also showing greater HbA1c reductions (1.3 ± 1.1 vs 0.9 ± 1.2%; P = 0.022). This genetic effect remained significant even after adjustment for other confounding factors (OR = 2.00, 95% CI = 1.03-3.89).Polymorphism in the GLP-1 receptor may influence DPP-4 inhibitor response. Further studies in larger population will help determine the association between genetic variation and interindividual differences in DPP-4 inhibitor therapy.

Efficacy and safety of linagliptin according to patient baseline characteristics: A pooled analysis of three phase 3 trials

BACKGROUND AND AIMS

We aimed to determine if patient baseline characteristics affect responses to linagliptin and identify relevant predictors of glycated hemoglobin (HbA1c) reduction in patients with type 2 diabetes mellitus (T2DM).

METHODS AND RESULTS

Data were pooled from three 24-week, placebo-controlled trials of similar design (linagliptin, n = 1651; placebo, n = 607). Patients were categorized according to baseline characteristics: age, T2DM duration, gender, body mass index (BMI), Homeostasis Model Assessment of Insulin Resistance (HOMA-IR), and metabolic syndrome (MetS). Changes from baseline in HbA1c after 24 weeks were assessed with analysis of covariance (ANCOVA). The proportion of patients with baseline HbA1c >7% achieving HbA1c of ≤7% at week 24 were evaluated. Independent predictors of HbA1c response with linagliptin were analyzed in a multivariate analysis with ANCOVA. Linagliptin treatment led to significant mean (SE) placebo-corrected reductions from baseline in HbA1c across all subgroups (-0.42% [±0.11] to -0.79% [0.08]; all p < 0.001). Within subgroups, HbA1c reduction was more pronounced in patients without MetS (-0.74% [0.06]; treatment interaction p = 0.0489). The proportion of patients with baseline HbA1c >7% achieving a target HbA1c ≤7% was greater with linagliptin versus placebo (30.2% vs 11.5%; odds ratio 3.82; 95% CI 2.82 to 5.17; p < 0.001). Characteristics significantly predicting HbA1c reductions after 24 weeks were fasting plasma glucose and race (both p < 0.05).

CONCLUSION

This post-hoc analysis supports that linagliptin achieved clinically meaningful improvements in hyperglycemia in patients with diverse clinical characteristics. These improvements were more pronounced in patients without MetS.

Effects of sitagliptin as initial therapy in newly diagnosed elderly type 2 diabetics: A randomized controlled study

The objective of this study was to investigate the characteristics of blood glycemic excursion, incretins and pancreatic hormone secretion in elderly people with newly diagnosed type 2 diabetes mellitus (T2DM) and to study the effects of sitagliptin on glycemic excursion in these subjects. A total of 129 newly diagnosed T2DM patients were enrolled in the study from March 2012 to August 2013. Clinical data, serum incretin, pancreatic hormone and continuous glucose monitoring data were collected. Among these subjects, elderly patients (NEDM) randomly received metformin combined with sitagliptin phosphate or glimepiride for 24 weeks. The blood glucose, glycosylated hemoglobin A_1c (GHbA_1c), serum incretins and pancreatic hormone levels were determined. During the oral glucose tolerance test (OGTT), 30 min insulin and C-peptide levels, 120 min insulin levels and ratio of the increases of insulin and blood glucose levels after 30 min of sugar loading (∆Ins30/∆Glu30) were significantly lower in elderly patients than in middle-aged patients (P<0.05). In addition, the glucagon elevation at 30 min was higher and the glucagon-like peptide-1 (GLP-1) at 30 min was lower in the elderly patients (P<0.05). Glucose excursion indices, including the standard deviation of the average blood glucose, intraday mean average glucose excursions (MAGE), and mean of daily differences (MODD), were significantly higher in the elderly patients (P<0.05). During the OGTT, insulin, C-peptide and ∆Ins30/∆Glu30 results at 30 min and GLP-1 levels at 120 min in NEDM subjects were significantly increased (P<0.05) and glucagon levels at 30 min was significantly lower after sitagliptin treatment (P<0.05) compared with glimepiride. Moreover, MAGE and MODD were significantly lower in the sitagliptin group after treatment compared to those in the glimepiride group (P<0.05). No severe hypoglycemia or cardiovascular diseases were observed. Strong blood glucose excursions occur in elderly patients with newly diagnosed T2DM. Sitagliptin phosphate combined with metformin effectively and safely improves glycemic excursion and carbohydrate metabolism in NEDM patients by promoting the first phase of insulin and incretin secretion and inhibiting glucagon secretion of.

Precision medicine: The future in diabetes care?

Personalized medicine aims at better targeting therapeutic intervention to the individual to maximize benefit and minimize harm. Type 2 diabetes (T2D) is a heterogeneous disease from a genetic, pathophysiological and clinical point of view. Thus, the response to any antidiabetic medication may considerably vary between individuals. Numerous glucose-lowering agents, with different mechanisms of action, have been developed, a diversified armamentarium that offers the possibility of a patient-centred therapeutic approach. In the current clinical practice, a personalized approach is only based upon phenotype, taking into account patient and disease individual characteristics. If this approach may help increase both efficacy and safety outcomes, there remains considerable room for improvement. In recent years, many efforts were taken to identify genetic and genotype SNP's (Single Nucleotide Polymorphism's) variants that influence the pharmacokinetics, pharmacodynamics, and ultimately the therapeutic response of oral glucose-lowering drugs. This approach mainly concerns metformin, sulphonylureas, meglitinides and thiazolidinediones, with only scarce data concerning gliptins and gliflozins yet. However, the contribution of pharmacogenetics and pharmacogenomics to personalized therapy still needs to mature greatly before routine clinical implementation is possible. This review discusses both opportunities and challenges of precision medicine and how this new paradigm may lead to a better individualized treatment of T2D.

Efficacy of hypoglycemic treatment in type 2 diabetes stratified by age or diagnosed age: a meta-analysis

AIM

To compare the effects of blood glucose lowering regimens in groups of patients categorized by baseline age and diagnosed age.

METHODS

Placebo-controlled randomized trials in type 2 diabetes patients with a study length ≥12 weeks were included.

RESULTS

A total of 246 trials were included. HbA1c changes from baseline corrected by placebo were comparable in sulfonylurea treatment between older and younger patients' groups (weighted mean difference (WMD), -1.28% vs -0.92%, p > 0.05). Treatment with metformin between groups resulted in a comparable change in HbA1c levels (WMD, -0.97% vs -1.23%, p > 0.05). Treatment with α-glucosidase inhibitor (WMD, -0.68% vs -0.67%, p > 0.05), treatment with thiazolidinedione (WMD, -0.74% vs -1.01%, p > 0.05), treatment with DPP-4 inhibitors (WMD, -0.67% vs -0.67%, p > 0.05), and treatment with SGLT2 inhibitors (WMD, -0.54% vs -0.67%, p > 0.05) between groups also resulted in comparable HbA1c changes. Treatment with GLP-1 analogs between groups in HbA1c changes were also comparable (p > 0.05). Regression analysis indicated that the baseline age or diagnosed age was not associated with the HbA1c changes from baseline.

CONCLUSION

In each hypoglycemic treatment, the baseline age or diagnosed age was not associated with the HbA1c changes from baseline.

Clinical and genetic predictors of dipeptidyl peptidase-4 inhibitor treatment response in Type 2 diabetes mellitus

AIM

To determine the clinical and genetic predictors of the dipeptidyl peptidase-4 (DPP-4) inhibitor treatment response in Type 2 diabetes mellitus (T2DM) patients.

PATIENTS & METHODS

DPP4, WFS1 and KCNJ11 gene polymorphisms were genotyped in a cohort study of 662 T2DM patients treated with DPP-4 inhibitors sitagliptin, vildagliptin or linagliptin. Genotyping was performed by Applied Biosystems TaqMan SNP genotyping assay.

RESULTS

Patients with triglyceride levels less than 1.7 mmol/l (odds ratio [OR]: 2.2.; 95% CI: 1.031-4.723), diastolic blood pressure (DBP) less than 90 mmHg (OR: 1.7; 95% CI: 1.009-2.892) and KCNJ11 rs2285676 (genotype CC) (OR: 2.0; 95% CI: 1.025-3.767) were more likely to response to DPP-4 inhibitor treatment compared with other patients, as measured by HbA1c levels.

CONCLUSION

Triglycerides, DBP and KCNJ11 rs2285676 are predictors of the DPP-4 inhibitor treatment response in T2DM patients.

Pharmacogenetics: Implications for Modern Type 2 Diabetes Therapy

Many clinical treatment studies have reported remarkable interindividual variability in the response to pharmaceutical drugs, and uncovered the existence of inadequate treatment response, non-response, and even adverse drug reactions. Pharmacogenetics addresses the impact of genetic variants on treatment outcome including side-effects. In recent years, it has also entered the field of clinical diabetes research. In modern type 2 diabetes therapy, metformin is established as first-line drug. The latest pharmaceutical developments, including incretin mimetics, dipeptidyl peptidase 4 inhibitors (gliptins), and sodium/glucose cotransporter 2 inhibitors (gliflozins), are currently experiencing a marked increase in clinical use, while the prescriptions of α-glucosidase inhibitors, sulfonylureas, meglitinides (glinides), and thiazolidinediones (glitazones) are declining, predominantly because of reported side-effects. This review summarizes the current knowledge about gene-drug interactions observed in therapy studies with the above drugs. We report drug interactions with candidate genes involved in the pharmacokinetics (e.g., drug transporters) and pharmacodynamics (drug targets and downstream signaling steps) of the drugs, with known type 2 diabetes risk genes and previously unknown genes derived from hypothesis-free approaches such as genome-wide association studies. Moreover, some new and promising candidate genes for future pharmacogenetic assessment are highlighted. Finally, we critically appraise the current state of type 2 diabetes pharmacogenetics in the light of its impact on therapeutic decisions, and we refer to major problems, and make suggestions for future efforts in this field to help improve the clinical relevance of the results, and to establish genetically determined treatment failure.

Identification of predictors of response to basal insulin and DPP4 inhibitors in patients with type 2 diabetes failing to other therapies

AIM

Basal insulin and DPP4 inhibitors are both possible options in patients with type 2 diabetes failing to oral drugs. The identification of clinical predictors of success with either one of the two approaches could be of help in personalizing therapy.

METHODS

The retrospective study was performed on a consecutive series of patients with type 2 diabetes (n = 1,002) failing to at least one oral agent, who had been prescribed either basal insulin or DPP4 inhibitors in the previous 2 years, with a duration of follow-up of at least 6 months. Clinical predictors of success after 6 months from the beginning of second-line treatment were identified in the cohort.

RESULTS

Among patients receiving a prescription of basal insulin, the proportion of therapeutic success at 6 months was 26.5 %. At multivariate analysis, a higher age and BMI, and a lower duration of diabetes were associated with success, as well as treatment with acarbose; conversely, a history of ischemic heart disease was associated with failure. Prescription of DPP4 inhibitors produced a therapeutic success in 24.8 % of cases. At multivariate analysis, success was associated with a lower baseline HbA1c and duration of diabetes, and a higher BMI and comorbidity; in addition, a lower success rate was found in women after adjusting for other confounders.

CONCLUSIONS

The present data support the view that insulin treatment is preferable in patients with severe hyperglycemia, failing to one or more drugs, whereas DPP4 inhibitors appear to be more useful in those with comorbid conditions.

Clinical Characteristics and Metabolic Predictors of Rapid Responders to Dipeptidyl Peptidase-4 Inhibitor as an Add-on Therapy to Sulfonylurea and Metformin

BACKGROUND

Dipeptidyl peptidase-4 (DPP-4) inhibitor add-on therapy is a new option for patients with inadequately controlled type 2 diabetes who are taking combined metformin and sulfonylurea (SU). We evaluated the efficacy and safety of this triple therapy and the characteristics of rapid responders and hypoglycemia-prone patients.

METHODS

We included 807 patients with type 2 diabetes who were prescribed a newly added DPP-4 inhibitor to ongoing metformin and SU in 2009 to 2011. Glycemia and other metabolic parameters at baseline, 12, 24, and 52 weeks, as well as episodes of hypoglycemia were analyzed. Rapid responders were defined as patients with ≥25% reduction in glycosylated hemoglobin (HbA1c) within 12 weeks.

RESULTS

At baseline, while on the submaximal metformin and SU combination, the mean HbA1c level was 8.4%. Twelve weeks after initiation of DPP-4 inhibitor add-on, 269 patients (34.4%) achieved an HbA1c level ≤7%. Sixty-six patients (8.2%, 47 men) were rapid responders. The duration of diabetes was shorter in rapid responders, and their baseline fasting plasma glucose (FPG), HbA1c, C-peptide, and homeostasis model assessment of insulin resistance were significantly higher. Patients who experienced hypoglycemia after taking DPP-4 inhibitor add-on were more likely to be female, to have a lower body weight and lower triglyceride and FPG levels, and to have higher homeostasis model assessment of β-cells.

CONCLUSION

An oral hypoglycemic triple agent combination including a DPP-4 inhibitor was effective in patients with uncontrolled diabetes. Proactive dose reduction of SU should be considered when a DPP-4 inhibitor is added for rapid responders and hypoglycemia-prone patients.

Subclinical Hypothyroidism and Type 2 Diabetes: A Systematic Review and Meta-Analysis

Background

Abundant evidence suggests an association between subclinical hypothyroidism (SCH) and type 2 diabetes mellitus (T2DM), but small sample sizes and inconclusive data in the literature complicate this assertion.

Objective

We measured the prevalence of SCH in T2DM population, and investigated whether T2DM increase the risk of SCH and whether SCH was associated with diabetic complications.

METHODS

We conducted a meta-analysis using PubMed, EMBASE, Web of Science, Wan Fang, CNKI and VIP databases for literature search. We obtained studies published between January 1, 1980 to December 1, 2014. The studies were selected to evaluate the prevalence of SCH in T2DM subjects, compare the prevalence of SCH in T2DM subjects with those non-diabetics, and investigate whether diabetic complications were more prevalent in SCH than those who were euthyroid. Fixed and random effects meta-analysis models were used, and the outcome was presented as a pooled prevalence with 95% confidence interval (95% CI) or a summary odds ratio (OR) with 95% CI.

RESULTS

Through literature search, 36 articles met the inclusion criteria and these articles contained a total of 61 studies. Funnel plots and Egger’s tests showed no publication bias in our studies, except for the pooled prevalence of SCH in T2DM (P = 0.08) and OR for SCH in T2DM (P = 0.04). Trim and fill method was used to correct the results and five potential missing data were replaced respectively. The adjusted pooled prevalence of SCH in T2DM patients was 10.2%, meanwhile, T2DM was associated with a 1.93-fold increase in risk of SCH (95% CI: 1.66, 2.24). Furthermore, SCH might affect the development of diabetic complications with an overall OR of 1.74 (95% CI: 1.34, 2.28) for diabetic nephropathy, 1.42 (95% CI: 1.21, 1.67) for diabetic retinopathy, 1.85 (95% CI: 1.35, 2.54) for peripheral arterial disease, and 1.87 (95% CI: 1.06, 3.28) for diabetic peripheral neuropathy.

Conclusions

T2DM patients are more likely to have SCH when compared with healthy population and SCH may be associated with increased diabetic complications. It is necessary to screen thyroid function in patients with T2DM, and appropriate individualized treatments in addition to thyroid function test should be given to T2DM patients with SCH as well.

Predictive Factors for Efficacy of Dipeptidyl Peptidase-4 Inhibitors in Patients with Type 2 Diabetes Mellitus

BACKGROUND

Predictive factors for the efficacy of dipeptidyl peptidase-4 (DPP-4) inhibitors for lowering glycosylated hemoglobin (HbA1c) remain unclear in patients with type 2 diabetes mellitus. The aim of this study is therefore to clarify predictive factors of the efficacy of DPP-4 inhibitors for lowering HbA1c after 12 months of treatment.

METHODS

A total of 191 consecutive type 2 diabetic patients (male sex 55%, mean age, 68.3±35.8 years), who had been treated with DPP-4 inhibitors for 12 months, were enrolled in this study and evaluated retrospectively.

RESULTS

After 12 months of DPP-4 inhibitor treatment, random blood glucose level, and HbA1c level, decreased from 167±63 to 151±49 mg/dL (P<0.01), and from 7.5%±1.3% to 6.9%±0.9% (P<0.01) respectively, without severe side effects. Multiple regression analysis showed that predictors of DPP-4 inhibitor treatment efficacy in lowering HbA1c level after 12 months were a decrease in HbA1c level after 3 months of treatment, a high baseline HbA1c level, a low baseline body mass index, and the absence of coronary artery disease.

CONCLUSION

Most suitable candidates for treatment with DPP-4 inhibitors are diabetics who are not obese and do not have coronary artery disease. In addition, long-term efficacy of DPP-4 inhibitors can be predicted by decrement of HbA1c after 3 months of treatment.

Cardiometabolic Effects of a New Class of Antidiabetic Agents

PURPOSE

Within the past decade, many new classes of drugs have received approval from the US Food and Drug Administration for treatment of type 2 diabetes mellitus, including glucagon-like peptide-1agonists, dipeptidyl peptidase-4 inhibitors, and the sodium-glucose cotransporter-2 inhibitors. Many trials have been performed, and several more are currently ongoing to evaluate these drugs. This review addresses the broad therapeutic and pleiotropic effects of these drugs. The review also discusses the role of these drugs in the treatment paradigm for type 2 diabetes and identifies patients who would be suitable candidates for treatment with these drugs.

METHODS

In this comprehensive evidence-based review, the following databases were searched from 1990 to the present: PubMed/MEDLINE, Scopus, CINAHL, ClinicalTrials.gov, the World Health Organization International Clinical Trials Registry Portal, and the American Diabetes Association and European Association for the Study of Diabetes abstract databases. Randomized clinical trials (RCTs) were only included for the main therapeutic and cardiovascular (CV) effects of these drug classes. For pleiotropic effects, RCTs were included unless no RCTs exist, in which case other studies as specified in the detailed Methods section were included.

FINDINGS

All 3 drug classes are effective in lowering hemoglobin A1c between 0.4% and 1.4%, depending on the drug class and population selected. These drug classes have beneficial effects on CV risk factors, such as weight, lipids, and blood pressure, in addition to lowering blood glucose levels. The CV tolerability of some drugs has been evaluated and found to be neutral; however, most trials are currently ongoing to assess CV tolerability. There are no concrete guidelines to determine where these drugs fit in the diabetes management paradigm, and there are ongoing trials to determine the best combination drug with metformin.

IMPLICATIONS

These 3 drug classes will potentially increase the armamentarium against hyperglycemia. However, the specific combinations with other antidiabetic drugs and populations that will best benefit from these drugs are still being tested. Future research is also being conducted on the use of glucagon-like peptide-1 receptor agonists and sodium-glucose cotransporter-2 inhibitors in patients with type 1 diabetes.

A nomogram to estimate the HbA1c response to different DPP-4 inhibitors in type 2 diabetes: a systematic review and meta-analysis of 98 trials with 24 163 patients

OBJECTIVES

To develop a nomogram for estimating the glycated haemoglobin (HbA1c) response to different dipeptidyl peptidase-4 (DPP-4) inhibitors in type 2 diabetes.

DESIGN

A systematic review and meta-analysis of randomised controlled trials (RCTs) of DPP-4 inhibitors (vildagliptin, sitagliptin, saxagliptin, linagliptin and alogliptin) on HbA1c were conducted. Electronic searches were carried out up to December 2013. Trials were included if they were carried out on participants with type 2 diabetes, lasted at least 12 weeks, included at least 30 participants and had a final assessment of HbA1c. A random effect model was used to pool data. A nomogram was used to represent results of the metaregression model.

PARTICIPANTS

Adults with type 2 diabetes.

INTERVENTIONS

Any DPP-4 inhibitor (vildagliptin, sitagliptin, saxagliptin, linagliptin or alogliptin).

OUTCOME MEASURES

The HbA1c response to each DPP-4 inhibitor within 1 year of therapy.

RESULTS

We screened 928 citations and reviewed 98 articles reporting 98 RCTs with 100 arms in 24 163 participants. There were 26 arms with vildagliptin, 37 with sitagliptin, 13 with saxagliptin, 13 with linagliptin and 11 with alogliptin. For all 100 arms, the mean baseline HbA1c value was 8.05% (64 mmol/mol); the decrease of HbA1c from baseline was -0.77% (95% CI -0.82 to -0.72%), with high heterogeneity (I(2)=96%). Multivariable metaregression model that included baseline HbA1c, type of DPP-4 inhibitor and fasting glucose explained 58% of variance between studies, with no significant interaction between them. Other factors, including age, previous diabetes drugs and duration of treatment added low predictive power (<1%). The nomogram estimates the absolute HbA1c reduction from baseline using the type of DPP-4 inhibitor, baseline values of HbA1c and fasting glucose.

CONCLUSIONS

Baseline HbA1c level and fasting glucose explain most of the variance in HbA1c change in response to DPP-4 inhibitors: each increase of 1.0% units HbA1c provides a 0.4-0.5% units greater fall.

Predicting efficacy of dipeptidyl peptidase-4 inhibitors in patients with type 2 diabetes: Association of glycated hemoglobin reduction with serum eicosapentaenoic acid and docosahexaenoic acid levels

This study was initiated to identify clinical and dietary parameters that predict efficacy of dipeptidyl peptidase‐4 inhibitors. A total of 72 untreated Japanese patients with type 2 diabetes who received DPP‐4 inhibitors (sitagliptin, alogliptin or vildagliptin) for 4 months were examined for changes of glycated hemoglobin (HbA_1c) and body mass index (BMI), and self‐administered 3‐day food records, as well as serum levels of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). DPP‐4 inhibitors significantly reduced HbA_1c (before initiation of DPP‐4 inhibitors 7.2 ± 0.7%, 4 months after initiation of DPP‐4 inhibitors 6.7 ± 0.6% [paired t‐test, P < 0.01 vs before]). Multiple regression analysis showed that changes of HbA_1c were significantly correlated with baseline HbA_1c, as well as estimated intake of fish. Furthermore, changes of HbA_1c were significantly correlated with serum levels of EPA (r = −0.624, P < 0.01) and DHA (r = −0.577, P < 0.01). HbA_1c reduction by DPP‐4 inhibitors is significantly correlated with estimated intake of fish and serum levels of EPA and DHA. (J Diabetes Invest, doi: 10.1111/j.2040‐1124.2012.00214.x, 2012)

Reshaping diabetes care: the fundamental role of dipeptidyl peptidase-4 inhibitors and glucagon-like peptide-1 receptor agonists in clinical practice

OBJECTIVE

To update clinicians on the most recent safety and efficacy data on current incretin-based strategies for the treatment of type 2 diabetes (T2D).

METHODS

Title searches were conducted in the Pubmed database to identify literature pertaining to the safety and efficacy of glucagon-like peptide-1 receptor agonists (GLP-1RAs) and dipeptidyl peptidase-4 (DPP-4) inhibitors. Product-specific title searches included the terms exenatide, liraglutide, linagliptin, saxagliptin, sitagliptin, and vildagliptin.

RESULTS

The recent literature has introduced us to newer DPP-4 inhibitors and longer-acting GLP-1RAs, updated meta-analyses assessing the safety and efficacy of incretin-based therapies, and studies exploring the use of incretin-based treatments in broader clinical settings such as combination therapy with insulin. Meta-analyses have demonstrated placebo-adjusted glycated hemoglobin (HbA1c) reductions of ~1% with GLP-1RAs and 0.6 to 0.8% with DPP-4 inhibitors and have suggested cardioprotective effects such as reduction of cardiovascular events and improvement of lipid profile. As a class, these agents have consistently demonstrated low risks of hypoglycemia relative to other agents.

CONCLUSION

Incretin-based therapies are characterized by an overall favorable safety profile and weight effect, a low risk of hypoglycemia, and clinically meaningful improvements in HbA1c. Based on an expanding and favorable literature describing their use in various patient populations, the guidelines of the American Association of Clinical Endocrinologists and the recently updated guidelines from the American Diabetes Association assign these agents a central role in the treatment of T2D.

Incretin-based therapies: focus on effects beyond glycemic control alone

Type 2 diabetes is associated with a high prevalence of comorbidities resulting from hypertension, dyslipidemia, and hyperglycemia. Inadequate management of these risk factors will eventually result in detrimental health consequences. Thus, the effect of a drug on factors such as weight, cardiovascular (CV) risk factors, and adherence is important to consider. A review was undertaken of the recent medical literature describing the extraglycemic characteristics of the two classes of incretin-based therapies-glucagon-like peptide-1 receptor agonists (GLP-1RA) and dipeptidyl peptidase-4 (DPP-4) inhibitors. PubMed searches were performed to identify published data on incretin therapies that describe their effects on CV risk factors, CV events, and factors related to medication adherence. The maintenance or loss of weight associated with the use of GLP-1RAs and DPP-4 inhibitors is well described in the medical literature. These agents also appear to be associated with a modest decrease in blood pressure and a reduced risk of CV events. In addition, several characteristics of incretin therapies may improve rates of medication adherence, such as generally favorable tolerability profiles (particularly with DPP-4 inhibitors), the availability of formulations that simplify treatment regimens, and a low risk for hypoglycemia. The literature on incretin therapies describes a number of clinical characteristics that are relevant to the management of extraglycemic risk factors. As part of a holistic treatment strategy, these properties constitute important considerations for tailoring therapy to individual patients with type 2 diabetes.

What are the preferred strategies for control of glycaemic variability in patients with type 2 diabetes mellitus?

The aim of therapy in type 2 diabetes in terms of blood glucose control is to reduce to target levels HbA1c and to reduce glycaemic variability in order to avoid both hypoglycaemia and wide excursions of postprandial glucose. The first approach to reduce glycaemic variability should consider a dietary and behavioural approach aiming to limit the glycaemic index and the glycaemic load of food and the prescription and implementation of a physical activity plan appropriate for the subject. From the pharmacological point of view, the diabetes specialist has now a much richer therapeutic armamentarium. The therapeutic algorithms can help the physician to choose the most appropriate drug. The traditional approach involves: i) metformin, acting mainly on fasting blood glucose; ii) sulphonylureas, that have shown a number of drawbacks, including the high risk of hypoglycemia; iii) pioglitazone, with a substantial effect on fasting and postprandial glucose and a low risk of hypoglycaemia; iv) insulin, that can be utilized with the basal or prandial approach. The new drugs belonging to the class of dipeptidyl peptidase-4 inhibitors have shown the reduction of postprandial glucose, a neutral effect on weight increase, a good safety profile and preliminary positive cardiovascular effects. When excess weight prevails, the glucagon-like peptide-1 agonists may be the preferred choice for their effect on weight reduction, reduction of hyperinsulinism and glycaemic variability.

Cardiovascular effects of dipeptidyl peptidase-4 inhibitors: from risk factors to clinical outcomes

Dipeptidyl peptidase-4 (DPP-4) inhibitors (gliptins) are oral incretin-based glucose-lowering agents with proven efficacy and safety in the management of type 2 diabetes mellitus (T2DM). In addition, preclinical data and mechanistic studies suggest a possible additional non-glycemic beneficial action on blood vessels and the heart, via both glucagon-like peptide-1-dependent and glucagon-like peptide-1-independent effects. As a matter of fact, DPP-4 inhibitors improve several cardiovascular risk factors: they improve glucose control (mainly by reducing the risk of postprandial hyperglycemia) and are weight neutral; may lower blood pressure somewhat; improve postprandial (and even fasting) lipemia; reduce inflammatory markers; diminish oxidative stress; improve endothelial function; and reduce platelet aggregation in patients with T2DM. In addition, positive effects on the myocardium have been described in patients with ischemic heart disease. Results of post hoc analyses of phase 2/3 controlled trials suggest a possible cardioprotective effect with a trend (sometimes significant) toward lower incidence of major cardiovascular events with sitagliptin, vildagliptin, saxagliptin, linagliptin, or alogliptin compared with placebo or other active glucose-lowering agents. However, the definite relationship between DPP-4 inhibition and better cardiovascular outcomes remains to be proven. Major prospective clinical trials involving various DPP-4 inhibitors with predefined cardiovascular outcomes are under way in patients with T2DM and a high-risk cardiovascular profile: the Sitagliptin Cardiovascular Outcome Study (TECOS) on sitagliptin, the Saxagliptin Assessment of Vascular Outcomes Recorded in Patients With Diabetes Mellitus-Thrombolysis in Myocardial Infarction (SAVOR-TIMI) 53 trial on saxagliptin, the Cardiovascular Outcomes Study of Alogliptin in Subjects With Type 2 Diabetes and Acute Coronary Syndrome (EXAMINE) trial on alogliptin, and the Cardiovascular Outcome Study of Linagliptin Versus Glimepiride in Patients With Type 2 Diabetes (CAROLINA) on linagliptin. If these trials confirm that a DPP-4 inhibitor can reduce the cardiovascular burden of T2DM, it would be major progress that would dramatically influence the management of the disease.

Sodium-glucose co-transporter 2 inhibitors and the potential for cardiovascular risk reduction in patients with type 2 diabetes mellitus

BACKGROUND

Clinical development programs of investigational antidiabetic agents now include evaluation of cardiovascular (CV) risk as a major research focus. Recently, several compounds in a new class of antihyperglycemic therapy have reached the final stages of development. Treatment with inhibitors of sodium-glucose co-transporters 2 (SGLT2) leads to urinary excretion of glucose in patients with type 2 diabetes mellitus (T2DM), and is associated with clinically significant reductions in blood glucose levels. The glucosuria-based mechanism of this class has the potential to induce weight loss through reduced caloric availability, and, in addition, may affect blood pressure (BP) via osmotic diuresis or other as yet incompletely characterized mechanisms.

METHODS

Searches of the PubMed database were conducted for published studies evaluating the use of SGLT2 inhibitors that reported data on CV risk factors (eg, weight, BP, lipid levels) or CV events. Searches for presentations at recent major diabetes congresses were performed using the Online Submission and Invitation System.

RESULTS

Treatment with SGLT2 inhibitors has consistently been associated with reduction in body weight and BP. Qualitative graphical assessment of 21 studies shows unadjusted reductions in systolic BP and body weight typically ranging between 3 to 5 mm Hg and 2 to 3 kg, respectively. A few reports have suggested the potential for improvement in lipid parameters, such as high-density lipoprotein cholesterol levels; however, not all studies have demonstrated significant changes, and some have noted small increases in low-density lipoprotein cholesterol levels.

CONCLUSION

Inhibition of SGLT2 in patients with T2DM may be associated with significant weight loss and BP reduction that are sustainable over the average time span of an investigational clinical study (ie, 3-6 months). When considered in terms of the potential for combination therapy, these features may offer a means of further reducing metabolic and CV risk in patients with T2DM.

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.

Effect of vildagliptin on glucose and insulin concentrations during a 24-hour period in type 2 diabetes patients with different ranges of baseline hemoglobin A1c levels

BACKGROUND

Currently, it is still unknown whether differences in glycemic control have any effect on glucose and insulin kinetics after vildagliptin administration. The aim of this study was to evaluate the effect of vildagliptin on glucose and insulin concentrations during a 24-h period in type 2 diabetes patients with different ranges of baseline hemoglobin A1c (A1C) levels.

PATIENTS AND METHODS

A randomized, double-blind, crossover, placebo-controlled clinical trial was carried out in 12 drug-naive adult volunteers with type 2 diabetes and overweight or obesity. Subjects had fasting glucose values between 7.2 and 13.3 mmol/L. Six patients had A1C between 7.0% and 8.4% (Group A), and the remaining subjects had A1C between 8.5% and 10.0% (Group B). Patients received oral administration of vildagliptin (50 mg twice daily) or placebo in a crossover manner for two consecutive days. Until the second day of the interventions, glucose and insulin concentrations were measured every hour during a 24-h period, and areas under the curve (AUCs) were calculated. Statistical analyses were evaluated with Wilcoxon and Mann-Whitney U tests.

RESULTS

There were significant decreases in glucose concentrations after vildagliptin administration in both groups when comparing placebo in all measurements throughout the 24-h period and in the AUC. There were no significant changes in insulin concentration in both groups after vildagliptin administration when comparing placebo in all measurements throughout the 24-h period and in the AUC.

CONCLUSIONS

Vildagliptin administration improved glucose control during a 24-h period in type 2 diabetes patients, independent of the basal A1C level, without changes in insulin levels.

Profile of vildagliptin in type 2 diabetes: efficacy, safety, and patient acceptability

Vildagliptin is a selective and potent dipeptidyl peptidase-4 inhibitor that improves glycemic control by inhibiting the degradation of both endogenous glucagon-like peptide-1 and glucose-dependent insulinotropic peptide. This article is a comprehensive review of the safety and efficacy of vildagliptin in patients with type 2 diabetes. Clinical evidence has proven that it effectively decreases hemoglobin A_1c with a low risk of hypoglycemia and is weight neutral. The addition of vildagliptin to metformin improves glucose control and significantly reduces gastrointestinal adverse events, particularly in patients inadequately controlled with metformin monotherapy. Its long-term advantages include preservation of β-cell function, reduction in total cholesterol, decrease in fasting lipolysis in adipose tissue, and triglyceride storage in non-fat tissues. Vildagliptin is well tolerated with a low incidence of AEs, and it does not increase the risk of cardiovascular/cerebrovascular (CCV) events. It can be taken before or after meals, and has little drug interaction, thus it will be well accepted.

Evolving therapeutic options for type 2 diabetes mellitus: an overview

INTRODUCTION

Many oral antidiabetic drugs (OADs) are available for patients with type 2 diabetes mellitus (T2DM). However, it is recognized that additional therapies are needed and several new compounds are in advanced stages of development.

PURPOSE

This narrative review considers the essential features of a successful OAD, the main classes of OADs that are currently used, and the therapies that may be available in the upcoming years.

RESULTS AND CONCLUSIONS

The first OADs (sulfonylureas and biguanides) were discovered by chance. Although effective in reducing blood glucose levels, early sulfonylureas were associated with significant off-target effects, and the biguanide phenformin was discontinued due to adverse events. Although metformin is in the same drug class, it has a better safety profile and is now recommended as first-line treatment, except when contraindicated. Nonetheless, many patients require additional glucose control (even on metformin) with an agent that has a complementary mechanism of action. Developments in bench science have facilitated the selection of agents for specific therapeutic targets, with the thiazolidinediones providing an interesting example. This OAD class initially appeared encouraging, yet in clinical practice was associated with safety concerns. As a result, newer agents, such as dipeptidyl peptidase-4 inhibitors, are undergoing more rigorous safety evaluations than OADs of previous generations. Promising compounds with novel mechanisms of action include the sodium-glucose co-transporter 2 inhibitors, the G-protein-coupled receptor agonists, and the balanced dual peroxisome proliferator-activated receptor-α/γ agonists. There is optimism that in the next few years, novel classes of OADs that are currently under development will offer additional blood glucose control options via complementary mechanisms of action. However, history has shown that compounds of the same class can have different safety profiles and treatment effects. Therefore, high-quality clinical trial evidence is needed for every compound.

A novel model-based meta-analysis to indirectly estimate the comparative efficacy of two medications: an example using DPP-4 inhibitors, sitagliptin and linagliptin, in treatment of type 2 diabetes mellitus

OBJECTIVES

To develop a longitudinal statistical model to indirectly estimate the comparative efficacies of two drugs, using model-based meta-analysis (MBMA). Comparison of two oral dipeptidyl peptidase (DPP)-4 inhibitors, sitagliptin and linagliptin, for type 2 diabetes mellitus (T2DM) treatment was used as an example.

DESIGN

Systematic review with MBMA.

DATA SOURCES

MEDLINE, EMBASE, http://www.ClinicalTrials.gov, Cochrane review of DPP-4 inhibitors for T2DM, sitagliptin trials on Food and Drug Administration website to December 2011 and linagliptin data from the manufacturer.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Double-blind, randomised controlled clinical trials, ≥12 weeks' duration, that analysed sitagliptin or linagliptin efficacies as changes in glycated haemoglobin (HbA1c) levels, in adults with T2DM and HbA1c >7%, irrespective of background medication. MODEL DEVELOPMENT AND APPLICATION: A Bayesian model was fitted (Markov Chain Monte Carlo method). The final model described HbA1c levels as function of time, dose, baseline HbA1c, washout status/duration and ethnicity. Other covariates showed no major impact on model parameters and were not included. For the indirect comparison, a population of 1000 patients was simulated from the model with a racial composition reflecting the average racial distribution of the linagliptin trials, and baseline HbA1c of 8%.

RESULTS

The model was developed using longitudinal data from 11 234 patients (10 linagliptin, 15 sitagliptin trials), and assessed by internal evaluation techniques, demonstrating that the model adequately described the observations. Simulations showed both linagliptin 5 mg and sitagliptin 100 mg reduced HbA1c by 0.81% (placebo-adjusted) at week 24. Credible intervals for participants without washout were -0.88 to -0.75 (linagliptin) and -0.89 to -0.73 (sitagliptin), and for those with washout, -0.91 to -0.76 (linagliptin) and -0.91 to -0.75 (sitagliptin).

CONCLUSIONS

This study demonstrates the use of longitudinal MBMA in the field of diabetes treatment. Based on an example evaluating HbA1c reduction with linagliptin versus sitagliptin, the model used seems a valid approach for indirect drug comparisons.

Cardiovascular effects of gliptins

Dipeptidyl peptidase 4 (DPP-4) inhibitors (commonly referred to as gliptins) are a novel class of oral antihyperglycaemic agents with demonstrated efficacy in the treatment of type 2 diabetes mellitus (T2DM). Preclinical data and mechanistic studies have indicated a possible beneficial action on blood vessels and the heart, via both glucagon-like peptide 1 (GLP-1)-dependent and GLP-1-independent effects. DPP-4 inhibition increases the concentration of many peptides with potential vasoactive and cardioprotective effects. Clinically, DPP-4 inhibitors improve several risk factors in patients with T2DM. They improve blood glucose control (mainly by reducing postprandial glycaemia), are weight neutral (or even induce modest weight loss), lower blood pressure, improve postprandial lipaemia, reduce inflammatory markers, diminish oxidative stress, and improve endothelial function. Some positive effects on the heart have also been described in patients with ischaemic heart disease or congestive heart failure, although their clinical relevance requires further investigation. Post-hoc analyses of phase II-III, controlled trials suggest a possible cardioprotective effect with a trend for a lower incidence of major cardiovascular events with gliptins than with placebo or active agents. However, the actual relationship between DPP-4 inhibition and cardiovascular outcomes remains to be proven. Major prospective clinical trials with predefined cardiovascular outcomes and involving various DPP-4 inhibitors are now underway in patients with T2DM and a high-risk cardiovascular profile.

Comparative clinical pharmacokinetics of dipeptidyl peptidase-4 inhibitors

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

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.