Sitagliptin added to voglibose monotherapy improves glycemic control in patients with type 2 diabetes

An Update on Dipeptidyl Peptidase-IV Inhibiting Peptides

Diabetes is a chronic metabolic disorder. According to the International Diabetes Federation, about 537 million people are living with diabetes. The two types of diabetes are type 1 diabetes mellitus (T1DM) and type 2 diabetes mellitus (T2DM), among which the population affected by T2DM is relatively higher. A major reason for T2DM is that insulin stimulation is hampered due to the inactivation of incretin hormones. Dipeptidyl peptidase-IV (DPP-IV) is a serine protease that is directly involved in the inactivation of incretin hormones, e.g., glucagon-like peptide-1 (GLP-1). Therefore, the inhibition of DPP-IV can be a promising method for managing T2DM, in addition to other enzyme inhibition strategies, such as inhibition of α-amylase and α -glucosidase. Currently, about 12 different gliptin drugs are available in the market that inhibit DPP-IV in a dose-dependent manner. Instead of gliptins, 'peptides' can also be employed as an alternative and promising way to inhibit DPP-IV. Peptide inhibitors of DPP-IV have been identified from various plants and animals. Chemically synthesized peptides have also been experimented for inhibiting DPP-IV. Most peptides have been analysed by biochemical assays, whereas some in vitro assays have also been reported. Molecular docking analysis has been applied to comprehend the mechanism of inhibition. In this review, certain aspects of natural as well as synthetic peptides are described that have been proven to inhibit DPP-IV.

A randomized, placebo-controlled trial to assess the efficacy and safety of sitagliptin in Japanese patients with type 2 diabetes and inadequate glycaemic control on ipragliflozin

AIMS

To investigate the efficacy, safety and tolerability of sitagliptin 50 mg once daily added to ipragliflozin 50 mg once daily monotherapy in Japanese patients with type 2 diabetes (T2D).

MATERIALS AND METHODS

Japanese patients with T2D and glycated haemoglobin (HbA1c) 7.0% to 10.0% while treated with ipragliflozin 50 mg once daily were randomized 1:1 to additional treatment with sitagliptin 50 mg once daily (N = 70) or matching placebo (N = 71) for 24 weeks. The primary efficacy endpoint was change in HbA1c at Week 24. Secondary efficacy endpoints were changes in 2-hour post-meal glucose (PMG), total PMG 0- to 2-hour area under the curve (AUC_0-2h ), and fasting plasma glucose (FPG).

RESULTS

Baseline characteristics were similar in the two groups (mean age 55.5 years, mean baseline HbA1c 8.0%). After 24 weeks, the addition of sitagliptin provided significantly greater reduction in HbA1c compared to placebo (least squares [LS] mean difference -0.83% [95% confidence interval -1.05, -0.62]; P <0.001). Significant reductions were also observed in all secondary endpoints: LS mean differences from placebo in changes in 2-hour PMG, total PMG AUC_0-2h , and FPG were -42.5 mg/dL, -67.0 mg·h/dL and -11.2 mg/dL, respectively (all P <0.001). The incidence of adverse events (AEs) overall and incidence of predefined AEs of clinical interest (symptomatic hypoglycaemia, urinary tract infection, genital infection, hypovolaemia and polyuria/pollakiuria) were similar in the two groups.

CONCLUSIONS

In Japanese patients with T2D, sitagliptin 50 mg once daily added to ipragliflozin 50 mg once daily monotherapy provided significant improvement in glycaemic control and was generally well tolerated. ClinicalTrials.gov: NCT02577016.

Comparison of Glycemic Excursion Using Flash Continuous Glucose Monitoring in Patients with Type 2 Diabetes Mellitus Before and After Treatment with Voglibose

Purpose: To determine the effect of Voglibose add-on therapy on daily glycemic excursions (using FreeStyle^® Libre Pro™, a Flash glucose monitoring system) in Indian patients with type 2 diabetes mellitus (T2DM) receiving a stable dose of metformin (Met) or metformin+sulfonylurea (Met+SU). Patients and Methods: T2DM patients with glycosylated hemoglobin (HbA1c) ≥7.0% and at least two postprandial excursions ≥140 mg/dL (within 2 h of meal) during the screening phase (visit 1/day -14 ± 2) were enrolled in this prospective, multicenter interventional study. The patients were randomized at visit 2 (day 0 ± 2) to receive Voglibose 0.2 or 0.3 mg tablets (BID/TID) as add-on therapy to Met and Met+SU. All the patients were followed at day 14 ± 2 (visit 3), month 3 ± 14 days (visit 4), 14 weeks (i.e., visit 4 + 14 days) ±2 days (visit 5), and month 6 ± 14 days (visit 6). Continuous glucose monitoring was performed to study glycemic excursions at visits 2, 3, and 5. The study outcomes were: change in average number of glycemic excursions per day, percent time spent in glucose fluctuations, mean Postprandial glucose (PPG), Fasting plasma glucose (FPG), day and night time mean glucose levels from baseline to day 14 and week 14; change in mean amplitude of glycemic excursion (MAGE) from baseline to 14 weeks; and mean HbA1c level at 3 and 6 months. Results: Out of 110 patients enrolled, 101 patients (91.8%) (Met+SU+Voglibose: 73 and Met+Voglibose: 28) completed the study. There was a significant decrease in average number of glycemic excursions per day from baseline to day 14 in the Met+Sul+Voglibose group and to week 14 in the Met+Voglibose group. There was also a significant reduction in percent time spent above target glucose range from baseline to day 14 in both treatment groups and to week 14 in the Met+SU+Voglibose group. A significant reduction in mean PPG area under the curve, day and night time mean glucose levels, and mean FPG levels from baseline to day 14 was reported in both treatment groups. A significant reduction in night time glucose, and average MAGE and HbA1c levels was reported from baseline to week 14 in the Met+Voglibose group and the Met+SU+Voglibose group, respectively. At 6 months, body weight, glucose levels, cholesterol, low-density lipoprotein-cholesterol, and HbA1c were significantly lower, especially in the Met+SU+Voglibose arm. Conclusion: Voglibose was useful in reducing glycemic variability and improving glycemic control in Asian Indian adults with T2DM. (CTRI/2018/04/013074).

Long-Term Safety and Efficacy of Sitagliptin for Type 2 Diabetes Mellitus in Japan: Results of a Multicentre, Open-Label, Observational Post-Marketing Surveillance Study

Introduction

A post-marketing surveillance (PMS) study was conducted to confirm the long-term risk–benefit profile of sitagliptin administered to Japanese patients with type 2 diabetes mellitus (T2DM) under real-world conditions.

Methods

This prospective, multicentre, open-label PMS collected data from 3326 patients receiving sitagliptin according to the approved indication during the case registration period (July 2010–June 2012; observation period, 3 years). Safety was assessed via collection of data on adverse drug reactions (ADRs), estimated glomerular filtration rate (eGFR) and cardiovascular events whereas efficacy was assessed via changes in glycated hemoglobin (HbA1c).

Results

In 3265 patients evaluated for safety, 270 ADRs occurred in 207 (6.3%) patients overall. Metabolism and nutrition disorders were the most common class of ADRs, occurring in 58 patients overall (53 non-serious, 5 serious) with hypoglycaemia (17 patients, 0.52%) the most common ADR. In patients with eGFR > 90 mL/min/1.73 m² at baseline (mean ± SD, 106.42 ± 18.11 mL/min/1.73 m², n = 584), eGFR declined by 11.83 ± 17.53 mL/min/1.73 m² (P < 0.0001; n = 360) over the observation period whereas eGFR appeared to be relatively maintained in patients with lower baseline eGFR levels. Cardiovascular events were infrequent [occurring in 4 of 84 (4.76%) patients at high cardiovascular risk] with no distinct features in this Japanese population and the cumulative incidence [8.42% (3.12–21.70) at 36 months; n = 32] was similar to that noted in previous studies involving sitagliptin. In patients evaluated for efficacy, the overall change in HbA1c from baseline to final evaluation was mean ± SD − 0.68 ± 1.34% (P < 0.0001, n = 2070). Reductions in HbA1c tended to be greater in younger patients and patients with higher body mass index (BMI) and HbA1c values at the start of administration.

Conclusion

Long-term sitagliptin administration in the routine clinical practice setting is associated with good efficacy, including as monotherapy, with no additional safety concerns.

Electronic supplementary material

The online version of this article (10.1007/s12325-020-01293-2) contains supplementary material, which is available to authorized users.

Factors associated with the glucose-lowering efficacy of sitagliptin in Japanese patients with type 2 diabetes mellitus: Pooled analysis of Japanese clinical trials

AIMS/INTRODUCTION

To explore the factors associated with the glucose-lowering efficacy of sitagliptin treatment in Japanese patients with type 2 diabetes mellitus.

MATERIALS AND METHODS

This was a post-hoc analysis of pooled data from seven sitagliptin phase II and III clinical studies carried out in Japan. All studies were double-blind, randomized, placebo-controlled, parallel-group and of 12-week duration. The analysis population consisted of 1,075 type 2 diabetes mellitus patients. In two of the trials, sitagliptin 50 mg and/or 100 mg daily were used as monotherapy; in five others, sitagliptin 50 mg daily was used as add-on treatment to ongoing pioglitazone, glimepiride, metformin, voglibose or glinides. Efficacy (reduction in hemoglobin A1c [HbA1c]) was evaluated in 12 sets of subgroups defined by demographic, glycemic, pancreatic β-cell function and insulin resistance parameters. An analysis of covariance model was used to evaluate the interaction between each parameter and efficacy.

RESULTS

Sitagliptin consistently provided a clinically meaningful reduction in HbA1c relative to placebo across all subgroups. Within subgroups, a greater absolute HbA1c reduction was associated with higher baseline HbA1c, fasting plasma glucose and 2-h post-meal glucose. Lower β-cell function, represented by homeostatic model assessment of β-cell function and insulinogenic index, was also associated with greater HbA1c reduction. In contrast, age, sex, body mass index, duration of type 2 diabetes mellitus and insulin resistance-related parameters did not interact with HbA1c changes.

CONCLUSIONS

Sitagliptin treatment was associated with clinically meaningful improvement in glycemic control in all subgroups of Japanese patients with type 2 diabetes mellitus that were evaluated. Higher baseline glycemic status and lower baseline β-cell function were identified as factors associated with greater HbA1c reduction after sitagliptin treatment.

Acarbose Add-on Therapy in Patients with Type 2 Diabetes Mellitus with Metformin and Sitagliptin Failure: A Multicenter, Randomized, Double-Blind, Placebo-Controlled Study

BACKGROUND

We evaluated the efficacy and safety of acarbose add-on therapy in Korean patients with type 2 diabetes mellitus (T2DM) who are inadequately controlled with metformin and sitagliptin.

METHODS

A total of 165 subjects were randomized to metformin and sitagliptin (Met+Sita, n=65), metformin, sitagliptin, and acarbose (Met+Sita+Acarb, n=66) and sitagliptin and acarbose (Sita+Acarb, exploratory assessment, n=34) therapy in five institutions in Korea. After 16 weeks of acarbose add-on or metformin-switch therapy, a triple combination therapy was maintained from week 16 to 24.

RESULTS

The add-on of acarbose (Met+Sita+Acarb group) demonstrated a 0.44%±0.08% (P<0.001 vs. baseline) decrease in glycosylated hemoglobin (HbA1c) at week 16, while changes in HbA1c were insignificant in the Met+Sita group (-0.09%±0.10%, P=0.113). After 8 weeks of triple combination therapy, HbA1c levels were comparable between Met+Sita and Met+Sita+Acarb group (7.66%±0.13% vs. 7.47%±0.12%, P=0.321). Acarbose add-on therapy demonstrated suppressed glucagon secretion (area under the curve of glucagon, 4,726.17±415.80 ng·min/L vs. 3,314.38±191.63 ng·min/L, P=0.004) in the absence of excess insulin secretion during the meal tolerance tests at week 16 versus baseline. The incidence of adverse or serious adverse events was similar between two groups.

CONCLUSION

In conclusion, a 16-week acarbose add-on therapy to metformin and sitagliptin, effectively lowered HbA1c without significant adverse events. Acarbose might be a good choice as a third-line therapy in addition to metformin and sitagliptin in Korean subjects with T2DM who have predominant postprandial hyperglycemia and a high carbohydrate intake.

Efficacy and safety of combination therapy with an α-glucosidase inhibitor and a dipeptidyl peptidase-4 inhibitor in patients with type 2 diabetes mellitus: A systematic review with meta-analysis

AIMS/INTRODUCTION

The combination of dipeptidyl peptidase-4 (DPP4) inhibitors and α-glucosidase inhibitors (AGIs) might provide an additive or synergistic glucose-lowering effect, as they have a complementary mode of action. In the present study, we examined the efficacy and safety of the addition of a DPP4 inhibitor to patients with type 2 diabetes inadequately controlled with an AGI.

MATERIALS AND METHODS

We carried out an electronic search of MEDLINE, EMBASE, the Cochrane Library and Clinicaltrials.gov through October 2016. Randomized controlled trials written in English that compared DPP4 inhibitors plus AGI (DPP4i/AGI) and placebo plus AGI (PCB/AGI) in patients with type 2 diabetes were selected. Data on the study characteristics, efficacy and safety outcomes were extracted, and the risk of potential biases was assessed. The efficacy and safety of DPP4i/AGI and PCB/AGI were compared.

RESULTS

Of 756 potentially relevant published articles and 40 registered trials, five studies including 845 patients randomized to DPP4i/AGI and 832 patients randomized to PCB/AGI were included for meta-analysis. Compared with PCB/AGI, DPP4i/AGI showed a greater reduction in glycated hemoglobin (weighted mean difference -1.2%, 95% confidence interval -1.6 to -0.8), fasting plasma glucose and 2-h postprandial plasma glucose levels, with no increase in bodyweight. The risks of hypoglycemia and gastrointestinal adverse events were similar between DPP4i/AGI and PCB/AGI.

CONCLUSIONS

The addition of a DPP4 inhibitor to patients with type 2 diabetes inadequately controlled with an AGI achieved better glycemic control without further increasing the risk of weight gain and hypoglycemia.

Renal Function During an Open-Label Prospective Observational Trial of Sitagliptin in Patients With Diabetes: A Sub-Analysis of the JAMP Study

BACKGROUND

The aim of the study was to determine the effects of sitagliptin on renal function in a diabetic population including patients with normal renal function.

METHODS

We analyzed the association between 12-month, 50 mg/day sitagliptin and renal function in outpatients with type 2 diabetes mellitus and poor blood glucose control in a subset of patients in the larger Januvia Multicenter Prospective Trial in Type 2 Diabetes observational study. Stratified analyses of changes in estimated glomerular filtration rate (eGFR) and urinary albumin-to-creatinine ratio (UACR) were performed. Factors associated with changes in eGFR at 3 months were examined by multivariate regression analysis.

RESULTS

Of the 779 patients enrolled, 585 were followed up for 12 months. eGFR decreased significantly from baseline at 3 and 12 months in patients with a baseline eGFR of ≥ 90 mL/min/1.73 m2 and in those with a baseline eGFR of ≥ 60 to < 90 mL/min/1.73 m2. Conversely, eGFR tended to increase at 3 and 12 months in patients with a baseline eGFR of ≥ 45 to < 60 mL/min/1.73 m2 and in those with a baseline eGFR of ≥ 30 to < 45 mL/min/1.73 m2. UACR decreased significantly (-21.6 (-46.8, 7.8)) at 3 months in patients with a baseline UACR of ≥ 30 mg/g Cre. Multivariate regression analysis of factors associated with changes in eGFR at 3 months revealed that higher baseline eGFR and greater decline in UACR were associated with more conspicuous decreases in eGFR.

CONCLUSIONS

In this group of diabetic patients receiving sitagliptin, eGFR declined in patients with high baseline eGFR, but not in those with a low baseline eGFR.

Network meta-analysis of liraglutide versus dipeptidyl peptidase-4 inhibitors for the treatment of type 2 diabetes in Japanese patients

AIMS

To determine the comparative efficacy and safety of liraglutide and dipeptidyl peptidase-4 (DPP-4) inhibitors as antidiabetics for Japanese patients with uncontrolled type 2 diabetes (T2DM).

METHODS AND MATERIALS

We searched for randomized controlled trials (RCTs) evaluating outcomes among Japanese adults with uncontrolled T2DM and including liraglutide or DPP-4 inhibitors up to August 2016. We extracted data on trial and patient characteristics, and the following outcomes: HbA1c, weight, patients meeting HbA1c <7%, patients experiencing hypoglycemic events, microalbuminuria, estimated glomerular filtration rate (eGFR) and creatinine. We synthesized data using network meta-analyses (NMA) using a Bayesian framework. Continuous outcomes were modeled using normal likelihoods and an identity link, while dichotomous outcomes were modeled using a binomial likelihood and a logit link.

RESULTS

The systematic literature review yielded 39 publications pertaining to 38 trials. A total of 27 trials (5032 patients) reported change in HbA1c at 12 weeks and at 24 weeks 9 trials (2091 patients). All treatments showed statistically significant reductions in HbA1c relative to placebo at 12 and 24 weeks. Liraglutide 0.9 mg was statistically superior to all DPP-4 interventions (vildagliptin, sitagliptin, linagliptin, alogliptin, teneligliptin, trelagliptin and omarigliptin) at 12 weeks and 24 weeks among those reporting. Treatments were not statistically differentiable with respect to weight change and risk of hypoglycemia. Finally, no comparisons of eGFR and microalbuminuria were conducted, as this data was reported in too few trials to conduct analyses.

LIMITATIONS

Some important outcomes were limited by poor reporting (eGFR and microalbuminuria) or low event rates (hypoglycemia). The follow-up time was relatively short. Clinically, the 24 week time point is more important as it demonstrates more sustained results.

CONCLUSIONS

Our research suggests that liraglutide 0.9 mg offers a more efficacious treatment option for T2DM than the DPP-4 inhibitors among adult Japanese patients and that it is a viable option for this population.

A Randomized, Placebo-Controlled Trial Evaluating the Safety and Efficacy of Adding Omarigliptin to Antihyperglycemic Therapies in Japanese Patients with Type 2 Diabetes and Inadequate Glycemic Control

INTRODUCTION

Daily dipeptidyl peptidase-4 (DPP-4) inhibitors are commonly used with other orally administered antihyperglycemic agents (AHA), as combination therapy, to treat Japanese patients with type 2 diabetes. When combination therapy is indicated, use of a once-weekly (q.w.) orally administered DPP-4 inhibitor might be an appropriate therapeutic option for some patients.

METHODS

A 52-week trial was conducted to assess the safety and tolerability (primary objectives) and glycemic efficacy (secondary objectives) of the q.w. DPP-4 inhibitor omarigliptin as add-on therapy to five different classes of orally administered AHA [sulfonylurea (SU), glinide (GL), biguanide (BG), thiazolidinedione (TZD), or α-glucosidase inhibitor (AGI)] commonly used in Japan and having different mechanisms of drug action from DPP-4 inhibitors. The trial consisted of an initial 24-week double-blind, placebo-controlled period during which patients (stratified by background AHA) were randomized to omarigliptin 25 mg q.w. or placebo, followed by a 28-week open-label period during which patients on placebo were switched to omarigliptin.

RESULTS

After 24 weeks, the percentages of patients with adverse events (AEs), serious AEs, drug-related AEs, AEs of symptomatic hypoglycemia, or who discontinued from trial medication because of an AE were generally similar in the omarigliptin and placebo groups, in all background AHA strata and in the overall population. From a mean baseline HbA1c of approximately 8.0%, the placebo-adjusted least-squares mean changes from baseline ranged from -0.80% (AGI stratum) to -1.16% (TZD stratum); p < 0.001 for all background AHA strata. During the open-label period, no safety signals emerged with longer-term treatment. At week 52, the change from baseline in HbA1c in the omarigliptin/omarigliptin group was similar to that of the placebo/omarigliptin group.

CONCLUSIONS

Addition of once-weekly omarigliptin to AHA therapy with an SU, GL, BG, TZD, or AGI for up to 52 weeks was generally safe and well tolerated, and provided persistent efficacy.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov: NCT01697592.

FUNDING

MSD K.K., a subsidiary of Merck & Co., Inc., Kenilworth, NJ, USA.

A randomized clinical trial of the safety and efficacy of sitagliptin in patients with type 2 diabetes mellitus inadequately controlled by acarbose alone

OBJECTIVE

To evaluate the safety and efficacy of sitagliptin when added to the treatment of patients with type 2 diabetes mellitus (T2DM) and inadequate glycemic control on acarbose monotherapy.

RESEARCH DESIGN AND METHODS

This was a multicenter, randomized, placebo-controlled, double-blind clinical trial. Patients (N = 381) with T2DM and inadequate glycemic control (glycated hemoglobin [HbA1c] ≥ 7.0% and ≤10.0%) on acarbose monotherapy (at least 50 mg three times daily) were randomized in a 1:1 ratio to receive the addition of sitagliptin 100 mg or matching placebo once daily for 24 weeks.

MAIN OUTCOME MEASURES

Changes from baseline in HbA1c and fasting plasma glucose (FPG) at Week 24.

RESULTS

The mean baseline HbA1c in randomized patients was 8.1%. At Week 24, the placebo-controlled, least squares mean changes from baseline (95% confidence interval) in HbA1c and FPG in the sitagliptin group were -0.62% and -0.8 mmol/L (p < .001), respectively. At Week 24, 37.8% of patients in the sitagliptin group were at HbA1c goal of <7% compared with 17.2% in the placebo group (p < .001). Sitagliptin was generally well tolerated, and there were no significant between-group differences in prespecified safety parameters (symptomatic hypoglycemia, diarrhea, abdominal pain, nausea, vomiting). A higher incidence of serious adverse events was observed in the sitagliptin group (5.2%) relative to placebo (0.5%); all but one, in the sitagliptin group, were not considered related to drug.

CONCLUSIONS

Sitagliptin was generally well tolerated and provided statistically superior and clinically meaningful improvements in glycemic control after 24 weeks of treatment compared to placebo when added to treatment of patients with inadequate glycemic control on acarbose monotherapy. Clinicaltrials.gov: NCT01177384.

Differential HbA1c response in the placebo arm of DPP-4 inhibitor clinical trials conducted in China compared to other countries: a systematic review and meta-analysis

BACKGROUND

It has been observed that the efficacy of dipeptidyl peptidase-4 (DPP-4) inhibitors as compared to the placebo groups in some clinical trials conducted in China is weaker than that in trials conducted outside China, leading to the suspicion that this may be caused by differential Glycosylated Hemoglobin (HbA1c) response in the placebo arm of DPP-4 inhibitor clinical trials conducted in China compared to other countries.

METHODS

We searched published articles and other documents related to phase III placebo-control trials of DPP-4 inhibitors in Type 2 diabetes mellitus (T2DM). We included studies from different countries and compared those conducted in China to those conducted in other countries. Meta-regression analysis was used to analyze the HbA1c response in the placebo arms.

RESULTS

A total of 66 studies met the inclusion criteria and 10 were conducted within China. There were a total of 8303 participants (mean age 56, male 57 %) in placebo groups. The pooled change in HbA1c for the placebo groups of 10 trials conducted in patients with T2DM in China was 0.26 % (95 % CI [-0.36 %, -0.16 %], p-value < 0.001), compared to 0.015 % (95 % CI [-0.05 %, 0.08 %], p-value is 0.637) for 56 trials conducted outside of China. The difference of placebo effect between trials conducted in and outside China is -0.273 % (95 % CI [-0.42 %, -0.13 %], p-value is less than 0.001) while after excluding trials conducted in Japan, the difference is -0.203 % (95 % CI [-0.35 %, -0.06 %], p-value is 0.005). They are both statistically significant.

CONCLUSIONS

The meta-analysis in the article demonstrates that there is statistically significant difference in the HbA1c response in the placebo arm of DPP-4 inhibitor clinical trials conducted in China compared to other countries. This differential HbA1c response in the placebo arm should be taken into consideration by both experimenters and medical decision makers when future DPP-4 studies are conducted in China.

Jiang Tang Xiao Ke Granule, a Classic Chinese Herbal Formula, Improves the Effect of Metformin on Lipid and Glucose Metabolism in Diabetic Mice

In the present study, the hypoglycemic, hypolipidemic, and antioxidative effects of metformin (MET) combined with Jiang Tang Xiao Ke (JTXK) granule derived from the “Di Huang Tang” were evaluated in mice with type 2 diabetes mellitus (DM) induced by high-fat diet/streptozotocin. DM mice were orally treated with MET (0.19 g/kg) either alone or combined with different doses (1.75, 3.5, or 7 g/kg) of JTXK for 4 weeks. Results showed that the serum and hepatic glucose, lipids, and oxidative stress levels were elevated in DM mice, when compared with the normal mice. MET treatment decreased FBG and serum glucagon levels of DM mice. Combination treatment with MET and JTXK 3.5 g/kg increased the hypoglycemia and insulin sensitivity at 4 weeks when compared with the DM mice treated with MET alone. However, neither MET nor MET/JTXK treatment could completely reverse the hyperglycemia in DM mice. JTXK enhanced the serum triglyceride (TG) and hepatic lipid-lowering effect of MET in a dose-dependent manner in DM mice. JTXK 1.75 and 3.5 g/kg improved the hepatoprotective effect of MET in DM mice. Synergistic effect of combination treatment with MET and JTXK on antioxidant stress was also found in DM mice compared with MET alone.

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.

Cardiovascular Effect of Incretin-Based Therapy in Patients with Type 2 Diabetes Mellitus: Systematic Review and Meta-Analysis

BACKGROUND

To assess the cardiovascular (CV) risk associated with the use of incretin-based therapy in adult patients with type 2 diabetes mellitus (T2DM) primary prevention group with low CV risks.

METHODS

The clinical studies on incretin-based therapy published in medical journals until August 2014 were comprehensively searched using MEDLINE, EMBASE and CENTRAL with no language restriction. The studies were systemically reviewed and evaluated for CV risks using a meta-analysis approach and where they meet the following criteria: clinical trial, incidence of predefined CV disease, T2DM with no comorbidities, age > 18 years old, duration of at least 12 weeks, incretin-based therapy compared with other antihyperglycaemic agents or placebo. Statistical analyses were performed using a Mantel-Haenszel (M-H) test. The odds ratios (OR) and their 95% confidence interval (CI) were estimated and displayed for comparison.

RESULTS

A total of 75 studies comprising 45,648 patients with T2DM were selected. The pooled estimate demonstrated no significance in decreased CV risk with incretin-based therapy versus control (M-H OR, 0.90; 95% CI, 0.81-1.00).

CONCLUSIONS

This meta-analysis suggests that incretin-based therapy show no significant protective effect on CV events in T2DM primary prevention group with low CV risks. Prospective randomized controlled trials are required to confirm the results of this analysis.

Safety and efficacy of addition of sitagliptin to rapid-acting insulin secretagogues for glycemic control, including post-prandial hyperglycemia, among Japanese with type 2 diabetes mellitus

The safety and efficacy of sitagliptin as add-on therapy to glinides, rapid-acting insulin secretagogues, were evaluated for Japanese patients with type 2 diabetes mellitus. This 52-week study consisted of a 12-week double-blind period, followed by a 40-week open-label period. During the double-blind period, patients were randomized to sitagliptin 50 mg q.d. (S/S group) or placebo (P/S group) as add-on therapy to glinide monotherapy. During the open-label period, all patients in both groups were administered sitagliptin 50 mg q.d. (or 100 mg q.d. after up-titration). During the double-blind period, the overall occurrence of adverse experiences (AE) was similar in both treatment groups. The frequency of reported AE of hypoglycemia in both groups was low and not notably different. The nature of clinical AE during the open-label period for both groups was not notably different from that of clinical AE in the sitagliptin group during the double-blind period. The between-group difference in HbA1c least squares (LS) mean of change from baseline (95 % CI) at Week 12 was -1.1 % (-1.3, -0.8) in favor of sitagliptin (P < 0.001). LS mean of reductions from baseline of fasting plasma glucose and 2-h postmeal glucose were significantly greater in the sitagliptin group than in the placebo group: -23.1 mg/dL (-32.2, -13.9) and -51.2 mg/dL (-67.4, -35.0), respectively (both P < 0.001). The changes from baseline in glycemic data in the S/S group remained generally stable throughout the 52-week treatment period.

Efficacy and safety of sitagliptin in Japanese patients with type 2 diabetes

BACKGROUND

The aim of this study was to investigate the clinical efficacy and safety of sitagliptin in Japanese patients with type 2 diabetes.

METHODS

A total of 3,247 subjects treated with sitagliptin were retrospectively recruited. Glucose parameters were collected at baseline, and 1, 3 and 6 months after initiation of sitagliptin. In addition, we explored factors that can be used to predict sitagliptin-induced reduction in HbA1c using linear mixed effect model. Factors associated with hypoglycemic events were examined by logistic analyses.

RESULTS

We analyzed the available data of 3,201 subjects (1,287 females). Treatment of sitagliptin significantly reduced HbA1c level from 7.44±1.20% at baseline to 6.73±0.99% at 6 months (P < 0.0001). Linear mixed effect model analyses demonstrated that reduction of HbA1c was associated with higher baseline HbA1c level, younger age, lower BMI and sitagliptin monotherapy. During this study, 82 cases of hypoglycemia were recorded. Logistic analyses indicated that hypoglycemic events were more frequent in female patients, and patients with low BMI, long history of type 2 diabetes, high HbA1c and on combination therapy experienced. Other adverse events were rare and mild.

CONCLUSIONS

Sitagliptin is effective for diabetic management and generally well tolerated in Japanese patients with type 2 diabetes. This trial was registered with UMIN (no. 000004121).

Glycemic/metabolic responses to identical meal tolerance tests at breakfast, lunch and dinner in Japanese patients with type 2 diabetes mellitus treated with a dipeptidyl peptidase-4 inhibitor and the effects of adding a mitiglinide/voglibose fixed-dose combination

BACKGROUND

The effects of the mitiglinide/voglibose fixed-dose combination on postprandial glycemic/metabolic responses in patients with type 2 diabetes mellitus (T2DM) treated with dipeptidyl peptidase-4 (DPP-4) inhibitors are unknown.

METHODS

Twelve T2DM patients treated with a DPP-4 inhibitor underwent identical meal tolerance tests (MTTs) at breakfast, lunch and dinner, before and 2 - 3 weeks after treatment with a fixed-dose combination of mitiglinide 10 mg and voglibose 0.2 mg (combination). Patients were randomized in a cross-over fashion to administer the combination either three-times-daily before each meal or twice-daily before breakfast and dinner. Glycemic/metabolic responses were evaluated at 0, 30, 60 and 120 min in each MTT.

RESULTS

Three-times-daily administration of the combination significantly suppressed postprandial hyperglycemia after each meal, particularly after lunch and dinner. Active glucagon-like peptide-1 levels increased significantly after each meal, as did early-phase insulin secretion without excessive insulin secretion. Postprandial hyperglycemia after lunch was significantly greater after twice-daily than three-times-daily administration, but there were no clinically relevant differences in other metabolic responses.

CONCLUSION

This study revealed that adding the mitiglinide/voglibose combination to a DPP-4 inhibitor elicited additive improvements in postprandial glycemic/metabolic responses assessed using MTTs at breakfast, lunch and dinner with identical meal compositions.

Efficacy of adding once- and thrice-daily voglibose in Japanese type 2 diabetic patients treated with alogliptin

We investigated the efficacy of once- and thrice-daily voglibose, an alpha-glucosidase inhibitor, as an add-on therapy to alogliptin, a dipeptidyl peptidase-4 inhibitor, on glycemic control in Japanese type 2 diabetic patients. In this 12-week, parallel-group, randomized, open-label, three-arm trial, 151 participants treated with alogliptin were randomly allocated to the following three arms; one was the group to initiate once-daily voglibose, another was to initiate thrice daily voglibose, and the other was the control group. The primary endpoint was the change of hemoglobin A1c levels at the end of the study, which was revealed to be significantly different among groups (p < 0.001). The once- and thrice-daily voglibose groups had a significantly greater reduction than the control group; the difference was -0.27% and -0.33% in the once- and thrice-daily voglibose group, respectively (both p < 0.001). No significant difference was observed between the two voglibose groups (p = 0.615). On the other hand, the increase of 1,5-anhydroglucitol levels were 3.3 and 5.5 μg/ml greater in the once- and thrice-daily voglibose groups than the control group (both p < 0.001). The thrice-daily voglibose group had a greater increase of 1,5- anhydroglucitol levels compared to the once-daily voglibose group (p = 0.005). In conclusion, once- and thrice-daily voglibose as an add-on to alogliptin significantly improved glycemic control in Japanese type 2 diabetic patients.