Factors influencing the durability of the glucose-lowering effect of sitagliptin combined with a sulfonylurea

Current Position of Gliclazide and Sulfonylureas in the Contemporary Treatment Paradigm for Type 2 Diabetes: A Scoping Review

The increasing burden of type 2 diabetes (T2D), in relation to alarming rise in the prevalence; challenges in the diagnosis, prevention, and treatment; as well as the substantial impact of disease on longevity and quality of life, is a major concern in healthcare worldwide. Sulfonylureas (SUs) have been a cornerstone of T2D pharmacotherapy for over 60 years as oral antidiabetic drugs (OADs), while the newer generation SUs, such as gliclazide modified release (MR), are known to be associated with low risk of hypoglycemia in addition to the cardiovascular neutrality. This scoping review aimed to specifically address the current position of gliclazide MR among other SUs in the contemporary treatment paradigm for T2D and to provide a practical guidance document to assist clinicians in using gliclazide MR in real-life clinical practice. The main topics addressed in this paper include the role of early and sustained glycemic control and use of SUs in T2D management, the properties of gliclazide MR in relation to its effectiveness and safety, the use of gliclazide therapy in special populations, and the place of SUs as a class and gliclazide MR specifically in the current T2D treatment algorithm.

iGlarLixi reduces residual hyperglycemia in Japanese patients with type 2 diabetes uncontrolled on basal insulin: A post-hoc analysis of the LixiLan JP-L trial

INTRODUCTION

Treatments for type 2 diabetes targeting baseline glucose levels but not postprandial glucose can result in normalized fasting blood glucose but suboptimal overall glycemic control (high glycated hemoglobin): residual hyperglycemia. In Japanese patients with type 2 diabetes the predominant pathophysiology is a lower insulin secretory capacity, and residual hyperglycemia is common with basal insulin treatment. Single-injection, fixed-ratio combinations of glucagon-like peptide-1 receptor agonists and basal insulin have been developed. iGlarLixi (insulin glargine 100 units/mL [iGlar]: lixisenatide ratio of 1 unit:1 µg) is for specific use in Japan. Post-hoc analysis of the LixiLan JP-L trial (NCT02752412) compared the effect of iGlarLixi with iGlar on this specific subpopulation with residual hyperglycemia.

MATERIALS AND METHODS

Outcomes at week 26 (based on the last observation carried forward) were assessed in patients in the modified intent-to-treat population with baseline residual hyperglycemia.

RESULTS

Overall, 83 (32.5%) patients in the iGlarLixi group and 79 (30.7%) patients in the iGlar group had baseline residual hyperglycemia. The proportion of patients with residual hyperglycemia at week 26 decreased to 15.7% in the iGlarLixi group, and increased to 36.9% in the iGlar group. Patients in the iGlarLixi group had significantly greater reductions in glycated hemoglobin compared with the iGlar group (-0.72% difference between groups; P < 0.0001).

CONCLUSIONS

New data from this post-hoc analysis of the JP-L trial show that treatment with the fixed-ratio combination iGlarLixi reduced the proportion of Japanese patients with residual hyperglycemia from baseline to week 26 and significantly reduced glycated hemoglobin vs similar doses of iGlar alone.

Phase III, randomized, double-blind, placebo-controlled study to evaluate the efficacy and safety of teneligliptin monotherapy in Chinese patients with type 2 diabetes mellitus inadequately controlled with diet and exercise

Aims/Introduction

Although the efficacy of teneligliptin, a highly selective dipeptidyl peptidase‐4 inhibitor, has been amply studied for the treatment of type 2 diabetes, no clinical trials of teneligliptin have been carried out in China. We evaluated the efficacy and safety of teneligliptin monotherapy compared with a placebo in Chinese patients with type 2 diabetes mellitus inadequately controlled with diet and exercise.

Materials and Methods

This multicenter, randomized, double‐blind, placebo‐controlled, parallel‐group study, carried out at 42 sites, enrolled type 2 diabetes patients with glycosylated hemoglobin 7.0 to <10.0% and fasting blood glucose <270 mg/dL. Patients were randomly assigned, in a 1:1 ratio, to treatment with 20 mg teneligliptin or a placebo (n = 127, each) administered orally once daily before breakfast for 24 weeks. Change in glycosylated hemoglobin from baseline to week 24 was the primary efficacy end‐point. Safety was assessed by the incidence of adverse events and adverse drug reactions.

Results

The least square mean (LSM) change in glycosylated hemoglobin from baseline to week 24 was −0.95% with teneligliptin versus −0.14% with a placebo, yielding an LSM difference (teneligliptin vs placebo) of −0.80% (P < 0.0001). For the secondary end‐point, from baseline to week 24, the LSM change in fasting blood glucose was −21.9 mg/dL with teneligliptin versus −1.4 mg/dL with a placebo, yielding an LSM difference (teneligliptin vs placebo) of −20.5 mg/dL (P < 0.0001). The adverse event and adverse drug reaction incidence rates, including hypoglycemia, were similar in both groups.

Conclusions

At 24 weeks, teneligliptin was generally well tolerated and effective in Chinese patients with type 2 diabetes mellitus inadequately controlled with diet and exercise.

The Unique Pharmacological and Pharmacokinetic Profile of Teneligliptin: Implications for Clinical Practice

Teneligliptin is a dipeptidyl peptidase-4 (DPP-4) inhibitor that was approved for the treatment of type 2 diabetes mellitus (T2DM) in Japan and Korea and is being researched in several countries. Teneligliptin is a potent, selective, and long-lasting DPP-4 inhibitor with a t_½ of approximately 24 h and unique pharmacokinetic properties: it is metabolized by cytochrome P450 (CYP) 3A4 and flavin-containing monooxygenase 3 (FMO3), or excreted from the kidney in an unchanged form. Because of its multiple elimination pathways, dose adjustment is not needed in patients with hepatic or renal impairment, and it is considered to have a low potential for drug–drug interactions. Clinical studies and postmarketing surveillance show that teneligliptin, administered as monotherapy and/or in combination with antihyperglycemic agents, is effective and well tolerated in T2DM patients, including in elderly patients and those with renal impairment. Furthermore, teneligliptin has antioxidative properties, which induce the antioxidant cascade, as well as ·OH scavenging properties. In addition, it has shown endothelial protective effects in several non-clinical and clinical studies. From its unique profile and clinical data, teneligliptin represents a potential therapeutic option in a wide variety of patients, including elderly diabetic patients and those with renal impairment. The fixed-dose combination (FDC) tablet of teneligliptin and canagliflozin has been approved in Japan; this is the first FDC tablet of a DPP-4 inhibitor and sodium glucose co-transporter 2 inhibitor in Japan, and the third globally. The FDC tablet may also provide additional prescribing and adherence benefits.

Factors involved in decreasing the therapeutic effect of sitagliptin: a subanalysis of the JAMP study

Objective

As a subanalysis of the Januvia Multicenter Prospective Trial in Type 2 Diabetes (JAMP study), we examined factors that decreased blood glucose control effect of sitagliptin after 3 months and patients requiring an addition or increase of diabetes treatment.

Methods

We selected patients in whom glycated hemoglobin (HbA1c) levels decreased by month 3 after initiation of sitagliptin treatment and conducted two analyses: (1) in patients who did not change drugs until month 12, we compared changes in HbA1c levels between concomitant drugs and examined factors that decreased blood glucose control effect of sitagliptin; (2) compared changes in HbA1c levels and backgrounds between patients who did and did not require an addition to or increased dose of the antidiabetic agent.

Results

Four hundred and ninety-eight patients were chosen. In 369 patients without drug change until month 12, changes in HbA1c levels during months 3-12 were not significantly different among concomitant drugs; factors causing rebound HbA1c were smoking and weight gain. Patient characteristics were compared between those who did and did not require an additional drug or a dose increase (n = 114) (n = 384). Drug changes were associated with longer disease duration, younger age, higher rate of smoking, and higher degree of insulin resistance but not with concomitantly administered drugs.

Conclusion

Smoking and weight gain were factors that decreased the effect of sitagliptin on reducing blood glucose levels. Differences in concomitant drugs did not affect sitagliptin's effects on glycemic control. A dose increase or the addition of the antidiabetic drug was not associated with concomitant drugs.

Comprehensive Evaluation of Combination Therapy with Basal Insulin and Either Lixisenatide or Vildagliptin in Japanese Patients with Type 2 Diabetes: A Randomized, Open-Label, Parallel-Group, Multicenter Study

INTRODUCTION

We comprehensively evaluated the effects of combination therapy with insulin glargine and the incretin-based drugs lixisenatide or vildagliptin in Japanese patients with type 2 diabetes.

METHODS

In this 12-week, randomized, open-label, parallel-group, multicenter study (GLP-ONE Kobe), the incretin-based drug sitagliptin was randomly switched to lixisenatide (20 μg/day, n = 18) or vildagliptin (100 mg/day, n = 20) in patients with inadequate glycemic control despite combination therapy with insulin glargine and sitagliptin. The dose of insulin glargine was titrated after the switch to maintain fasting blood glucose at approximately 110 mg/dL. The primary end points of the study were the change in glycosylated hemoglobin (HbA_1c) level between before and 12 weeks after the treatment switch, the proportion of patients achieving an HbA_1c level below 7.0%, and the postprandial increase in glucose concentration as assessed by self-monitoring of blood glucose.

RESULTS

The change in HbA_1c level from baseline to 12 weeks did not differ significantly between the lixisenatide and vildagliptin groups (- 0.6 ± 0.7% and - 0.6 ± 1.2%, respectively, P = 0.920). Neither the proportion of patients achieving an HbA_1c level below 7.0% nor the postprandial increase in glucose concentration was different between two groups. Body weight and serum low density lipoprotein (LDL) cholesterol level decreased significantly in the lixisenatide and vildagliptin groups, respectively. Both drugs were associated with mild gastrointestinal symptoms but not with severe hypoglycemia. Vildagliptin was associated with elevation of serum aspartate transaminase. Treatment satisfaction as assessed with the Diabetes Treatment Satisfaction Questionnaire did not differ significantly between the two groups.

CONCLUSION

The combinations of basal insulin and either lixisenatide or vildagliptin have similar efficacies with regard to improvement of glycemic control.

TRIAL REGISTRATION

This trial has been registered with UMIN (No. 000010769).

Relationship between deterioration of glycated hemoglobin-lowering effects in dipeptidyl peptidase-4 inhibitor monotherapy and dietary habits: Retrospective analysis of Japanese individuals with type 2 diabetes

The present study was designed to assess possible relationships between deterioration of the glycated hemoglobin (HbA1c)-lowering effects in dipeptidyl peptidase-4 inhibitor (DPP4i) monotherapy and macronutrient intake among individuals with type 2 diabetes. Type 2 diabetes patients who began and continued DPP4i monotherapy without any prescription change for 1 year were retrospectively stratified into two groups: (i) patients who maintained their HbA1c levels during the 0.5- to 1-year period after DPP4i initiation (group A, ΔHbA1c [1-0.5 year] <0.4%, n = 53); and (ii) those whose HbA1c levels increased [group B, ΔHbA1c (1-0.5 year] ≥0.4%, n = 10). Group B had significantly higher ΔHbA1c (1-0.5 year), Δbodyweight (1-0.5 year) and fat intake, especially of saturated and monounsaturated fats; the carbohydrate and protein intake were similar between groups. Multiple regression analyses showed that fat intake, especially saturated fat intake, was significantly correlated with ΔHbA1c (1-0.5 year). Thus, dietary habits, especially saturated fat intake, might well contribute to deterioration of the HbA1c-lowering effects in DPP4i monotherapy.

Efficacy and Safety of Teneligliptin 40 mg in Type 2 Diabetes: A Pooled Analysis of Two Phase III Clinical Studies

INTRODUCTION

Teneligliptin, an antihyperglycemic agent belonging to the dipeptidyl peptidase-4 inhibitor class, is usually prescribed at a dose of 20 mg/day. In Japan, the dose can be increased to 40 mg/day if needed. We examined the treatment response when the teneligliptin dose was increased from 20 to 40 mg in a post hoc pooled analysis of data from two 52-week, open-label, phase III clinical trials of teneligliptin 20-40 mg/day as monotherapy or combination treatment in Japanese patients with type 2 diabetes.

METHODS

In both studies, patients received teneligliptin 20 mg for at least 28 weeks; thereafter the dose was increased if glycemic control was inadequate. The data set for this post hoc analysis comprised those patients whose teneligliptin dose was increased to 40 mg at week 28 (N = 204). We assessed (i) the proportion of patients achieving HbA1c reduction after teneligliptin dose increase [≤ - 0.1% change in HbA1c during weeks 28-52 (24 weeks); responders] and (ii) the response to teneligliptin 40 mg according to whether or not patients experienced HbA1c re-elevation (≥ 0.1% increase) during 28 weeks of teneligliptin 20 mg.

RESULTS

Of 204 patients, 108 (52.9%) showed a response to teneligliptin 40 mg (HbA1c change ≤ - 0.1% during weeks 28-52) and had mean (± SD) HbA1c reduction of 0.50 ± 0.44%. Of patients showing re-elevation of HbA1c during treatment with teneligliptin 20 mg, 89/143 (62.2%) achieved HbA1c reduction after dose increase to 40 mg. Logistic regression analyses suggested that change in body weight is one of the parameters linked to HbA1c reduction after dose increase to teneligliptin 40 mg. The incidence of adverse events was not changed after teneligliptin dose increase.

CONCLUSION

Increasing the dosage of teneligliptin from 20 to 40 mg/day has potential as a well-tolerated and effective option for treating type 2 diabetes.

FUNDING

Mitsubishi Tanabe Pharma Corporation.

Long-term safety and efficacy of canagliflozin as add-on therapy to teneligliptin in Japanese patients with type 2 diabetes

AIM

To evaluate the long-term safety and efficacy of canagliflozin as add-on therapy in patients with type 2 diabetes mellitus (T2DM) who had inadequate glycaemic control with teneligliptin monotherapy.

METHODS

This open-label 52-week study was conducted in Japan. Patients received canagliflozin 100 mg added to teneligliptin 20 mg orally once daily for 52 weeks. The safety endpoint was the incidence of adverse events (AEs). The efficacy endpoints included changes in glycated haemoglobin (HbA1c), fasting plasma glucose (FPG) and body weight from baseline to week 52 (with last observation carried forward).

RESULTS

Overall, 153 patients entered the treatment period and 142 completed the study. The overall incidence rates of AEs and drug-related AEs were 69.9% and 22.9%, respectively. Most AEs and drug-related AEs were mild or moderate in severity. There were no previously undescribed safety signals. The mean changes in HbA1c, FPG and body weight were -0.99% (95% confidence interval [CI] -1.12 to -0.85), -38.6 mg/dL (95% CI -43.4 to -33.9) and -3.92% (95% CI -4.53 to -3.31), respectively. These effects were maintained for 52 weeks without attenuation. HbA1c and body weight were both decreased in 82.24% of patients at the end of the treatment period. Reductions in postprandial glucose were observed at weeks 24 and 52.

CONCLUSIONS

No new safety risks with this combination were identified, and sustained improvements in HbA1c, FPG and body weight were observed. The findings suggest that long-term co-administration of canagliflozin with teneligliptin is well tolerated and effective in Japanese patients with T2DM who have inadequate glycaemic control on teneligliptin alone.

β-Cell signalling and insulin secretagogues: A path for improved diabetes therapy

Insulin secretagogues including sulfonylureas, glinides and incretin-related drugs such as dipeptidyl peptidase 4 (DPP-4) inhibitors and glucagon-like peptide-1 receptor agonists are widely used for treatment of type 2 diabetes. In addition, glucokinase activators and G-protein-coupled receptor 40 (GPR40) agonists also have been developed, although the drugs are not clinically usable. These different drugs exert their effects on insulin secretion by different mechanisms. Recent advances in β-cell signalling studies have not only deepened our understanding of insulin secretion but also revealed novel mechanisms of insulin secretagogues. Clarification of the signalling mechanisms of the insulin secretagogues will contribute to improved drug therapy for diabetes.

Determinants of Long-Term Durable Glycemic Control in New-Onset Type 2 Diabetes Mellitus

BACKGROUND

Long-term durable glycemic control is a difficult goal in the management of type 2 diabetes mellitus (T2DM). We evaluated the factors associated with durable glycemic control in a real clinical setting.

METHODS

We retrospectively reviewed the medical records of 194 new-onset, drug-naïve patients with T2DM who were diagnosed between January 2011 and March 2013, and were followed up for >2 years. Glycemic durability was defined as the maintenance of optimal glycemic control (glycosylated hemoglobin [HbA1c] <7.0%) for 2 years without substitution or adding other glucose-lowering agents. Clinical factors and glycemic markers associated with glycemic durability were compared between two groups: a durability group and a non-durability group.

RESULTS

Patients in the durability group had a higher baseline body mass index (26.1 kg/m² vs. 24.9 kg/m²) and lower HbA1c (8.6% vs. 9.7%) than the non-durability group. The initial choice of glucose-lowering agents was similar in both groups, except for insulin and sulfonylureas, which were more frequently prescribed in the non-durability group. In multiple logistic regression analyses, higher levels of education, physical activity, and homeostasis model assessment of β-cell function (HOMA-β) were associated with glycemic durability. Notably, lower HbA1c (<7.0%) at baseline and first follow-up were significantly associated with glycemic durability (adjusted odds ratio [OR], 7.48; 95% confidence interval [CI], 2.51 to 22.3) (adjusted OR, 9.27; 95% CI, 1.62 to 53.1, respectively), after adjusting for confounding variables including the types of glucose-lowering agents.

CONCLUSION

Early achievement of HbA1c level within the glycemic target was a determinant of long-term glycemic durability in new-onset T2DM, as were higher levels of education, physical activity, and HOMA-β.

Effect of sitagliptin on blood glucose control in patients with type 2 diabetes mellitus who are treatment naive or poorly responsive to existing antidiabetic drugs: the JAMP study

BACKGROUND

To investigate the ameliorating effect of sitagliptin, a dipeptidyl peptidase-4 inhibitor, on blood glucose control in patients with type 2 diabetes mellitus who were previously untreated with or who have a poor responsive to existing antidiabetic drugs.

METHODS

Sitagliptin (50 mg/day) was added on to the pre-existing therapy for type 2 diabetes and changes in the glycated hemoglobin (HbA1c) level after 3 months of treatment were compared with the baseline and performed exploratory analysis.

RESULTS

HbA1c levels were significantly decreased after 1 month of treatment compared to baseline, with a mean change in HbA1c level from baseline of -0.73% (range, -0.80 to -0.67) in the entire study population at 3 months. Patients who received a medium dose of glimepiride showed the least improvement in HbA1c levels. The percentage of patients who achieved an HbA1c level of <7.0% significantly increased after 1 month of treatment, reaching 53.1% at 3 months. The percentage of patients who achieved a fasting blood glucose level of <130 mg/dL significantly increased after 1 month of treatment, reaching 50.9% at 3 months.

CONCLUSIONS

Sitagliptin improved the HbA1c level and rate of achieving the target control levels in patients with type 2 diabetes mellitus who were previously untreated with, or poorly responsive to, existing antidiabetic drugs. Thus, sitagliptin is expected to be useful in this patient group. However, the additional administration of sitagliptin in patients treated with medium-dose glimepiride only slightly improved blood glucose control when corrected for baseline HbA1c level.

Alogliptin for the treatment of type 2 diabetes: a drug safety evaluation

INTRODUCTION

Dipeptidyl peptidase-4 (DPP-4) inhibitors such as alogliptin are becoming more widely established as treatment options for patients with type 2 diabetes (T2DM) because of their ability to improve glycemic control without increasing the risk of hypoglycemia or weight gain. New therapies with improved safety profiles are needed, especially because of the chronic and progressive nature of T2DM.

AREAS COVERED

In this article, the overall safety and tolerability of alogliptin are evaluated based upon a review of the literature. In particular, adverse events (AEs) that have been of interest for the DPP-4 class of drugs, such as the risk of major cardiovascular (CV) events and acute pancreatitis, will be investigated in detail.

EXPERT OPINION

Alogliptin is generally well-tolerated in a broad range of patient populations including different ethnic groups and the elderly. In the pivotal EXAMINE clinical trial, alogliptin was found not to be associated with an increased risk of major CV events or acute pancreatitis/pancreatic cancer.

Incretin-based drugs for type 2 diabetes: Focus on East Asian perspectives

Type 2 diabetes in East Asians is characterized primarily by β‐cell dysfunction, and with less adiposity and less insulin resistance compared with that in Caucasians. Such pathophysiological differences can determine the appropriate therapeutics for the disease. Incretins, glucose‐dependent insulinotropic polypeptide and glucagon‐like peptide‐1, are secreted in response to meal ingestion, and enhance insulin secretion glucose‐dependently. Incretin‐based drugs, dipeptidyl peptidase‐4 inhibitors (DPP‐4i) and glucagon‐like peptide‐1 receptor agonists, that ameliorate β‐cell dysfunction with limited hypoglycemia risk are now widely used in type 2 diabetes management. Recent meta‐analyses of clinical trials on DPP‐4i and glucagon‐like peptide‐1 receptor agonists found that the drugs were more effective in Asians, most likely because of amelioration of β‐cell dysfunction. In addition, we found increased glycated hemoglobin‐lowering effects of DPP‐4i to be associated with intake of fish in type 2 diabetes, which suggests that dietary customs of East Asians might also underlie the greater efficacy of DPP‐4i. Despite the limited risk, cases of severe hypoglycemia were reported for DPP‐4i/sulfonylureas combinations. Importantly, hypoglycemia was more frequent in patients also receiving glibenclamide or glimepiride, which activate exchange protein directly activated by cyclic adenosine monophosphate 2, a critical mediator of incretin signaling, and was less frequent in patients receiving gliclazide, which does not activate exchange protein directly activated by cyclic adenosine monophosphate 2. Prevention of insulin‐associated hypoglycemia by DPP‐4i has gained attention with regard to the enhancement of hypoglycemia‐induced glucagon secretion by insulinotropic polypeptide, but remains to be investigated in East Asians. Despite the safety issues, which are paramount and must be carefully monitored, the incretin‐based drugs could have potential as a first choice therapy in East Asian type 2 diabetes patients.

A higher body mass index attenuates the long-term HbA1c-lowering effects of liraglutide in type 2 diabetes patients treated using sulfonylurea-based therapy

Objective

To identify the attenuating factor of glycated hemoglobin (HbA1c)-lowering effects of liraglutide in type 2 diabetes (T2D) patients over the long term.

Methods

Forty-six T2D patients received liraglutide-glimepiride combination therapy. Clinical characteristics were compared between the following two subgroups: the relapse group (≥0.4 % increase in HbA1c in 48 weeks compared to 12 weeks) and non-relapse group (remaining patients). A glucagon-loading test was performed to evaluate baseline endogenous insulin secretion.

Results

In the relapse group, significantly reduced HbA1c, as observed at 12 weeks, tended to increase at 24 and 48 weeks. In the non-relapse group, reduced HbA1c was maintained for 48 weeks. Body weight was decreased at 12 weeks and then recovered at 48 weeks in both groups. Baseline BMI was significantly higher in the relapse group than in the non-relapse group. Age, HbA1c, duration of diabetes, fasting C-peptide, daily glimepiride dose and the duration of glimepiride treatment were comparable between both groups. Multiple logistic regression analysis revealed that baseline BMI was independently associated with the relapse group.

Conclusion

A higher BMI is the leading factor for attenuating long-term glycemic control by liraglutide in T2D patients undergoing sulfonylurea-based therapy.

C-peptide immunoreactivity index is associated with improvement of HbA1c: 2-Year follow-up of sitagliptin use in patients with type 2 diabetes

AIMS

This retrospective study aimed to determine the hypoglycaemic effect of 2 years of sitagliptin administration in terms of changes in HbA1c and C-peptide immunoreactivity (CPR) index (plasma CPR [ng/mL]/glucose [mg/dL]×100).

METHODS

The inclusion criteria for DPP-4 inhibitor-naive outpatients with type 2 diabetes (n=285) were: continuation of sitagliptin for ≥700 days from initial administration and measurement of HbA1c, serum CPR, and plasma glucose levels at 0, 3, 6, 12, 18, and 24 months after sitagliptin initiation. Logistic regression analyses determined the factors contributing to the response to sitagliptin, based on responder (ΔHbA1c ≤-0.4% [≤-4 mmol/mol]) and non-responder (ΔHbA1c >-0.4% [>-4 mmol/mol]) groups.

RESULTS

The HbA1c level decreased and CPR index increased from baseline to 3, 6, 12, 18, and 24 months after the start of sitagliptin administration (HbA1c: 7.4 ± 0.8% [57 ± 9 mmol/mol], 7.3 ± 0.9% [57 ± 9 mmol/mol], 7.4 ± 0.9% [58 ± 10 mmol/mol], 7.1 ± 0.8% [55 ± 9 mmol/mol], and 7.3 ± 0.9% [57 ± 10 mmol/mol], respectively, all P<0.001 vs. baseline [8.0 ± 1.0%, 64 ± 11 mmol/mol] and CPR index: 1.69 ± 0.96, 1.71 ± 1.10, 1.62 ± 0.96, 1.64 ± 0.92, and 1.66 ± 0.96, respectively, all P<0.05 vs. baseline [1.47 ± 0.81]). Higher baseline HbA1c level, shorter diabetes duration, and greater CPR index increase after sitagliptin administration were associated with the response to sitagliptin.

CONCLUSIONS

Our results suggest that sitagliptin improves glycaemic control via an improved intrinsic insulin response.

β cell dysfunction versus insulin resistance in the pathogenesis of type 2 diabetes in East Asians

Type 2 diabetes (T2DM) is one of the most serious global health problems and is mainly a result of the drastic increase in East Asia, which includes over a fourth of the global diabetes population. Lifestyle factors and ethnicity are two determinants in the etiology of T2DM, and lifestyle changes such as higher fat intake and less physical activity link readily to T2DM in East Asians. It is widely recognized that T2DM in East Asians is characterized primarily by β cell dysfunction, which is evident immediately after ingestion of glucose or meal, and less adiposity compared to the disease in Caucasians. These pathophysiological differences have an important impact on therapeutic approaches. Here, we revisit the pathogenesis of T2DM in light of β cell dysfunction versus insulin resistance in East Asians and discuss ethnic differences in the contributions of insulin secretion and insulin resistance, together with incretin secretin and action, to glucose intolerance.

Efficacy and safety of luseogliflozin monotherapy in Japanese patients with type 2 diabetes mellitus: a 12-week, randomized, placebo-controlled, phase II study

OBJECTIVE

Luseogliflozin is a novel sodium glucose cotransporter 2 inhibitor for type 2 diabetes mellitus (T2DM) treatment. An exploratory Phase II study was conducted to assess the efficacy and safety of several doses of luseogliflozin in Japanese T2DM patients.

PATIENTS AND METHODS

Japanese T2DM patients aged 20-74 years with hemoglobin A1c (HbA1c) of 6.9-10.5%, fasting plasma glucose (FPG) ≥126 mg/dL and on diet therapy were randomized in a double-blind manner to receive luseogliflozin (0.5, 2.5, or 5 mg) or placebo once daily for 12 weeks (n = 61, 61, 61, and 56, respectively). The primary endpoint was the change in HbA1c from baseline to end of treatment. Other endpoints included FPG, 2 h postprandial plasma glucose (PPG) in a meal tolerance test (MTT), and body weight. Drug safety was also assessed.

TRIAL REGISTRATION

Japan Pharmaceutical Information Center (identifier: JapicCTI-090908).

RESULTS

Changes in HbA1c from baseline to end of treatment were -0.36, -0.62, and -0.75% in the 0.5, 2.5, and 5 mg luseogliflozin groups, respectively, versus +0.06% in the placebo group (all P < 0.001). The reductions in FPG and 2 h-PPG in the MTT were also significantly greater in the luseogliflozin groups (all P < 0.01) without increases in insulin levels from baseline. Luseogliflozin reduced body weight at all doses. There were no significant differences in the incidences of adverse events among groups. Most adverse events were mild in severity. There were no serious adverse events.

CONCLUSIONS

Although this was a small-scale study with a short duration, all tested doses of luseogliflozin significantly improved glycemic control, reduced body weight, and were well tolerated in Japanese T2DM patients over the 12-week treatment period.

Factors influencing the durability of the glucose-lowering effect of sitagliptin combined with a sulfonylurea

We analyzed the changes of glycemic control over 12 months and the factors influencing blood glucose in 162 Japanese patients with type 2 diabetes having inadequate glycemic control despite sulfonylurea-based therapy who received add-on sitagliptin. Hemoglobin A1c (HbA1c) decreased significantly after 4 weeks of treatment, and this improvement was maintained for 1 year, although HbA1c was slightly higher in week 52 than in week 24. Comparison of the patients showing a ≥0.4% increase of HbA1c between weeks 24 and 52 (n = 57) with the others (n = 105) showed a significant difference in the change of bodyweight, as well as the dose of glibenclamide (both P < 0.01). Although combined therapy with sitagliptin and a sulfonylurea seems to be effective for at least 1 year, blood glucose levels are more likely to increase again in patients who show greater weight gain after 24 weeks of treatment and those receiving a higher dose of glibenclamide.