Efficacy and safety of sitagliptin monotherapy and combination therapy in Japanese type 2 diabetes patients

Effects of sitagliptin on serum lipid levels in patients with type 2 diabetes: a systematic review and meta-analysis

AIM

Lipid abnormalities often occur in patients with diabetes mellitus and the coexistence of diabetes mellitus and dyslipidaemia will increase the risk of cardiovascular diseases. However, the specific effects of sitagliptin on lipid control remain elusive in diabetic patients. The aim of this meta-analysis is to investigate the effects of sitagliptin alone or with other antidiabetic agents on serum lipid control.

METHODS

PubMed, Cochrane Library, Embase and the ClinicalTrials.gov website were systematically searched from 2006 (the first year that sitagliptin entered market) to 16 January 2021. Eligible studies were randomized clinical trials (RCTs) of sitagliptin including outcomes of serum total cholesterol (TC), triglycerides, high-density lipoprotein cholesterol (HDL-C) or low-density lipoprotein cholesterol (LDL-C).

RESULTS

A total of 14 RCTs with 2654 patients were identified. Treatment with sitagliptin alone or in combination with other antidiabetic agents significantly reduced serum TC [mean difference (MD) = -5.52 95% confidence interval (95% CI), -7.88 to -3.15; P < 0.00001] and LDL-C (MD = -0.07; 95% CI, -0.14 to 0.00; P < 0.00001) in patients with type 2 diabetes. No statistical significances were found in serum triglycerides (MD = 1.53; 95% CI, -8.22 to 11.28; P = 0.76) or HDL-C (MD = 0.65; 95% CI, -1.59 to 0.29; P = 0.18). Subgroup analyses suggest that sitagliptin can significantly decrease serum LDL-C, TC and triglyceride levels compared with placebo alone, and no statistical significance was found in comparison with the serum HDLC levels.

CONCLUSION

Sitagliptin alone or in combination with other antidiabetic agents significantly reduces serum TC and LDL-C in patients with type 2 diabetes mellitus, while no significant difference was observed in serum triglycerides or HDL-C.

Application of machine learning methods for the development of antidiabetic drugs

Diabetes is a chronic non-communicable disease caused by several different routes, which has attracted increasing attention. In order to speed up the development of new selective drugs, machine learning (ML) technology has been applied in the process of diabetes drug development, which opens up a new blueprint for drug design. This review provides a comprehensive portrayal of the application of ML in antidiabetic drug use.

Real-world Observational Study on Patient Outcomes in Diabetes (RESPOND): study design and baseline characteristics of patients with type 2 diabetes newly initiating oral antidiabetic drug monotherapy in Japan

INTRODUCTION

To investigate factors affecting glycemic control, oral antidiabetic drug (OAD) treatment distribution and self-care activities among patients with type 2 diabetes mellitus (T2DM) who newly initiate OAD monotherapy in a real-world setting in Japan.

RESEARCH DESIGN AND METHODS

A Real-world Observational Study on Patient Outcomes in Diabetes (RESPOND) is an ongoing, prospective, observational cohort study with follow-up at 6, 12, 18 and 24 months. Primary objectives include OAD treatment patterns (cross-sectional and longitudinal) among diabetes specialists versus non-specialists; adherence to diabetes self-care activities; quality of life; treatment satisfaction among patients and target attainment rates of parameters, including glycated hemoglobin. Here, we present the study design and baseline data.

RESULTS

Of 1506 patients enrolled (June 2016-May 2017; 174 sites in Japan), 1485 were included in the baseline analysis (617 treated by specialists, 868 by non-specialists). Most patients were prescribed dipeptidyl peptidase-4 inhibitors (DPP-4Is) (specialist vs non-specialist, 54.1% vs 57.1%), then sodium-glucose cotransporter 2 inhibitors (13.9% vs 22.2%), metformin (20.3% vs 12.9%) and other OADs (<5% individually in both groups). Regardless of age, body mass index and glycated hemoglobin, DPP-4Is were the most commonly prescribed OADs by both specialists and non-specialists. About one-fifth and one-third of patients visiting specialists and non-specialists, respectively, received no advice on diet and exercise. The proportion of patients following self-care recommendations for diet and exercise (2/5 items on the Summary of Diabetes Self-Care Activities) was significantly higher among those visiting specialists than non-specialists.

CONCLUSION

The use of newer OAD was common across a broad range of clinical characteristics in patients with T2DM who newly initiated monotherapy in Japan. However, patient-related and physician-related factors could affect the treatment changes during the following course of treatment. In addition, treatment outcome could vary with the observed difference in the level of patient education provided by diabetes specialists versus non-specialists.

A Monocentric Retrospective Observational Study of Comorbidities in Patients Affected by Autoimmune Bullous Diseases

BACKGROUND/AIM

Autoimmune bullous diseases (AIBDs) of the skin and mucosae include a heterogeneous group of chronic diseases, which could be associated with various comorbidities. The purpose of this study was to evaluate the comorbidity profiles of patients affected by AIBDs, who referred to the Dermatological Clinic of Padua from December 2015 to June 2018.

PATIENTS AND METHODS

A monocentric retrospective observational study was conducted on 157 patients with diagnosis of AIBDs. Patients' comorbidities were investigated during the periodic visits of follow-up and through the analysis of computerized medical records.

RESULTS

Among the 157 patients, 40 (25.5%) were diagnosed with PV, 15 (9.6%) with PF, and 102 (64.9%) with BP. Nine different comorbidities were observed, but only two of these were statistically significantly associated with BP: type 2 diabetes (p=0.0142) and neuropsychiatric disorders (p=0.015).

CONCLUSION

BP is statistically significantly associated with type 2 diabetes mellitus and neuropsychiatric diseases. The correlation with neuropsychiatric pathologies is interesting for the possible bidirectional role in their etiology. The association with type 2 diabetes mellitus could suggest more caution in the administration of systemic corticosteroids, especially in elderly patients.

The dipeptidyl peptidase 4 inhibitor sitagliptin improves oxidative stress and ameliorates glomerular lesions in a rat model of type 1 diabetes

AIMS

Oxidative stress has been linked to the development and progression of diabetic nephropathy (DN). The present study evaluated whether the dipeptidyl peptidase-4 inhibitor sitagliptin attenuates glomerular lesions and oxidative stress evoked by chronic hyperglycemia, by a mechanism independent of insulin secretion and glycemia normalization.

MAIN METHODS

A rat model of DN caused by streptozotocin injection was established and the effects of sitagliptin (5 mg/kg/day) were evaluated after two weeks of treatment.

KEY FINDINGS

Sitagliptin treatment did not change body weight, glycemic and lipid profiles. However, histopathological observation revealed that sitagliptin attenuates diabetes-induced glomerular lesions on diabetic rats. Sitagliptin also ameliorated the increase in DPP-4 content and promoted the stabilization of GLP-1 in the diabetic kidney. Furthermore, sitagliptin treatment significantly attenuated the increase of free-radical formation and the decrease of antioxidant defenses, attenuating therefore the oxidative stress in the kidneys of diabetic animals.

SIGNIFICANCE

The results suggest that sitagliptin treatment alleviates kidney oxidative stress in type 1 diabetic rats, which could play a key role in reducing the progression of DN.

Efficacy and Safety of Adding Sitagliptin in Type 2 Diabetes Patients on Insulin: Age-Stratified Comparison at One Year in the ASSIST-K Study

Background

Sitagliptin, the first dipeptidyl peptidase-4 inhibitor, has demonstrated efficacy and safety as monotherapy and as add-on therapy to oral antidiabetic agents or insulin. However, there have been few reports about sitagliptin in elderly patients. The ASSIST-K observational study was performed in patients with type 2 diabetes mellitus (T2DM) receiving sitagliptin as add-on therapy to insulin. Changes of hemoglobin A1c (HbA1c), body weight, and the estimated glomerular filtration rate (eGFR), as well as adverse events, were investigated over 12 months in age-stratified groups.

Methods

Among outpatients with T2DM treated at member institutions of Kanagawa Physicians Association, those starting sitagliptin as add-on therapy to insulin were followed for 12 months. HbA1c (National Glycohemoglobin Standardization Program), body weight, and eGFR were the efficacy endpoints, while adverse events were investigated to assess safety. Patients were stratified into three age groups (≤ 64 years, 65 - 74 years, and ≥ 75 years) for comparison of the endpoints.

Results

Among 937 patients on insulin before starting sitagliptin, 821 patients were analyzed after excluding those without HbA1c data at baseline and 12 months. The two groups of elderly patients (65 - 74 years and ≥75 years) had more complications and their HbA1c was lower at initiation of sitagliptin therapy. The dose of sitagliptin, daily number of insulin injections, and number of concomitant oral antidiabetic agents were all lower in the elderly patients. HbA1c showed a significant decrease after initiation of sitagliptin in all age groups, and there were no significant intergroup differences in the change of HbA1c at 12 months. Body weight did not change significantly in any group. eGFR decreased significantly in all groups, with no significant intergroup differences at 12 months. Regarding adverse events, there were no significant intergroup differences in the incidence of severe hypoglycemia, gastrointestinal symptoms, or constipation.

Conclusions

Despite baseline differences in demographic factors and medications, sitagliptin showed good efficacy and safety in all age groups of patients receiving it as add-on therapy to insulin during routine management of T2DM. Adding sitagliptin to insulin achieves similar efficacy and safety outcomes at 12 months in both elderly and non-elderly T2DM patients.

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.

Comparative study of the effects of ipragliflozin and sitagliptin on multiple metabolic variables in Japanese patients with type 2 diabetes: A multicentre, randomized, prospective, open-label, active-controlled study

In the present randomized study, we assessed the efficacy of ipragliflozin compared with sitagliptin in 124 Japanese patients with type 2 diabetes. Sodium-glucose co-transporter-2 inhibitor-naïve and incretin-related agent-naïve patients were randomly assigned to receive additional 50 mg ipragliflozin or sitagliptin. The primary endpoint was the proportion of participants with >0.5% decrease in glycated haemoglobin (HbA1c) without body weight gain at 12 weeks. For secondary endpoints, we measured several biomarkers related to metabolic changes. After 12 weeks, 53.9% of participants in the ipragliflozin and 42.9% in the sitagliptin group reached the primary endpoint (P = 0.32). Decreases in homeostatic model assessment of insulin resistance, body fat percentage and skeletal muscle mass index, and increases in free fatty acids, ketone body concentration and HDL cholesterol levels were greater in the ipragliflozin group. Increases in homeostatic model assessment of β-cell function and decreases in proinsulin-to-insulin ratio were greater in the sitagliptin group. No serious adverse events occurred in either group. In conclusion, ipragliflozin had beneficial effects on fat reduction, insulin resistance and lipid metabolism, while sitagliptin had beneficial effects on β-cell function.

Characteristics of repaglinide effects on insulin secretion

The dynamics of insulin secretion stimulated by repaglinide, a glinide, and the combinatorial effects of repaglinide and incretin were investigated. At 4.4 mM glucose, repaglinide induced insulin secretion with a gradually increasing first phase, showing different dynamics from that induced by glimepiride, a sulfonylurea. In the presence of glucagon-like peptide-1 (GLP-1), insulin secretion by repaglinide was augmented significantly but to lesser extent and showed different dynamics from that by glimepiride. At 4.4 mM glucose, the intracellular Ca²⁺ level was gradually increased by repaglinide alone or repaglinide plus GLP-1, which differs from the Ca²⁺ dynamics by glimepiride alone or glimepiride plus GLP-1, suggesting that the difference in Ca²⁺ dynamics contributes to the difference in the dynamics of insulin secretion. At a higher concentration (8.8 mM) of glucose, the dynamics of insulin secretion stimulated by repaglinide was similar to that by glimepiride. Combination of repaglinide and GLP-1 significantly augmented insulin secretion, the amount of which was comparable to that by the combination of glimepiride and GLP-1. The Ca²⁺ dynamics was similar for repaglinide and glimepiride at 8.8 mM glucose. Our data indicate that repaglinide has characteristic properties in its effects on the dynamics of insulin secretion and intracellular Ca²⁺ and that the combination of repaglinide and GLP-1 stimulates insulin secretion more effectively than the combination of glimepiride and GLP-1 at a high concentration of glucose, providing a basis for its use in clinical settings.

Bullous Pemphigoid Associated with the Dipeptidyl Peptidase-4 Inhibitor Sitagliptin in a Patient with Liver Cirrhosis Complicated with Rapidly Progressive Hepatocellular Carcinoma

A 78-year-old man presented with cutaneous blisters of the limbs and abdominal distension. He had been treated for various diseases, including liver cirrhosis. He had begun receiving sitagliptin, a dipeptidyl peptidase-4 (DPP-4) inhibitor, for diabetes mellitus three years before the hospitalization. A skin biopsy demonstrated bullous pemphigoid. Ultrasonography (US) revealed multiple liver tumors, although he had been receiving regular US studies. We stopped sitagliptin and started insulin and corticosteroids. However, his renal dysfunction progressed, and he died 14 days after the hospitalization. We should therefore be careful of various complications, including bullous pemphigoid and progression of tumors, when using DPP-4 inhibitors.

Safety evaluation of trelagliptin in the treatment of Japanese type 2 diabetes mellitus patients

INTRODUCTION

Trelagliptin is a novel, long-acting dipeptidyl peptidase-4 (DPP-4) inhibitor approved for the treatment of type 2 diabetes mellitus (T2DM) in japan. The safety and efficacy of trelagliptin has been evaluated in three published clinical trials to date: one phase II and two phase III studies. As trelagliptin only requires dosing once per week, this new agent has the potential to improve compliance and subsequently, glycaemic control, in patients with T2DM. Areas covered: This article reviews the available safety data for trelagliptin from published clinical trials, and evaluates the published safety profile relative to competitor once-daily and once-weekly DPP-4 inhibitors. Expert opinion: Clinical trial data to date suggest that trelagliptin is a safe and efficacious medication with a similar safety profile to once-daily DPP-4 inhibitors, and to the once-weekly DPP-4 inhibitor, omarigliptin. Trelagliptin is well tolerated when given alone, and in combination with other anti-diabetic medications. An advantage of trelagliptin over existing once-daily DPP-4 inhibitors is the decrease of dosing frequency, rather than once-daily. No specific, serious adverse events have been reported for trelagliptin in published clinical trials, making it an attractive alternative to other DPP-4 inhibitors.

The Glucose-lowering Efficacy of Sitagliptin in Obese Japanese Patients with Type 2 Diabetes

Objective Dipeptidyl peptidase-4 (DPP-4) inhibitors are the most frequently prescribed oral hypoglycemic agents in Japan. Although a relationship between the efficacy of DPP-4 inhibitors and the body mass index (BMI) has been reported, this relationship is controversial. We investigated whether the BMI value affects the glucose-lowering efficacy of sitagliptin in obese Japanese patients with type 2 diabetes. Methods One hundred sixty-two outpatients with inadequate glycemic control were divided into four groups based on their baseline BMI values. They were then treated with sitagliptin (a DPP-4 inhibitor) for 3 months and followed-up for 12 months. Results Sitagliptin significantly reduced the hemoglobin A1c level (HbA1c: -0.71±0.55%) after 3 months, and continued to reduce the HbA1c level until 12 months. There was no significant difference in the efficacy of sitagliptin among the four BMI groups. A multiple linear regression analysis indicated that the factors contributing to the change in the HbA1c level were the baseline level of HbA1c and the homeostasis model assessment of β-cell function (HOMA-β). In terms of the relationship between the baseline BMI value and the efficacy of sitagliptin treatment, the number of patients who responded to sitagliptin treatment after 3 months was lowest in the group of patients with the highest BMI values. A multiple logistic regression analysis revealed that the baseline HOMA-β function and HbA1c level and a baseline BMI value of ≥30 kg/m² significantly contributed to the response to sitagliptin treatment. Conclusion The results indicated that sitagliptin treatment was effective in controlling glucose metabolism disorder in obese Japanese patients with type 2 diabetes. However, the efficacy of sitagliptin treatment might be attenuated in severely obese patients, such as those with a BMI value of ≥30 kg/m².

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.

Teneligliptin real-world efficacy assessment of type 2 diabetes mellitus patients in India (TREAT-INDIA study)

BACKGROUND AND AIMS

Teneligliptin was introduced in India in May 2015. It has gained popularity and is already widely prescribed in type 2 diabetes mellitus (T2DM). This "real life" data collection was conducted to assess the efficacy of teneligliptin in Indian T2DM patients.

METHODS

Predesigned structured proforma was used to collect information from the prescribing physicians regarding the efficacy of teneligliptin when prescribed as monotherapy as well as combination therapy with other antidiabetic drugs in T2DM patients. Information on the glycemic parameters at baseline prior to starting teneligliptin and at the end of 3 months therapy was collected. The efficacy was assessed by analyzing the mean change in 3-month values of glycosylated hemoglobin (HbA1c), fasting plasma glucose (FPG), and postprandial plasma glucose (PPG).

RESULTS

Data of 4305 patients was available for analysis. There was statistically significant improvement in mean HbA1c, FPG, and PPG with teneligliptin therapy. Means changes in HbA1c, FPG, and PPG were -1.37%±1.15%, 51.29±35.41 mg/dL, and 80.89±54.27 mg/dL, respectively. Subgroup analysis revealed that HbA1c (%) reduction with teneligliptin when used as monotherapy, add-on to metformin or add-on to metformin plus sulfonylureas combination, add-on to metformin plus alpha glucosidase inhibitor combination or add-on to insulin was 0.98±0.53, 1.07±0.83, 1.46±1.33, 1.43±0.80, and 1.55±1.05, respectively.

CONCLUSION

Real-world data suggests that teneligliptin significantly improves glycemic control in Indian patients with T2DM when prescribed either as monotherapy or as an add-on to one or more other commonly prescribed antidiabetic drugs.

Effects of vildagliptin as add-on treatment in patients with type 2 diabetes mellitus: insights from long-term clinical studies in Japan

BACKGROUND

Vildagliptin, a dipeptidyl peptidase-4 (DPP-4) inhibitor, is wildly used to treat type 2 diabetes mellitus (T2DM) with mono- or combination-therapy. We review two previously published open-label studies to extract insights on the long-term efficacy and safety of vildagliptin.

METHODS

Two studies were conducted in Japan to assess the efficacy and safety of vildagliptin as an add-on to other oral antidiabetes drugs (OADs) for 52 weeks. These studies were performed under the similar protocol in Japanese patients with T2DM who were inadequately controlled with OAD monotherapy [excluding other dipeptidyl peptidase-4 (DPP-4) inhibitors].

RESULTS

Addition of vildagliptin (50 mg twice daily) to other OAD monotherapy [sulfonylurea (SU), metformin, thiazolidinedione, alpha-glucosidase inhibitor and glinide] reduced glycated hemoglobin (HbA1c) levels by -0.64 %,-0.75 %,-0.92 %,-0.94 % and - 0.64 %, respectively, over 52 weeks of treatment. Overall, the incidence of hypoglycemia was low and was slightly higher in the add-on to SU treatment group compared with the other groups. The incidences of adverse events were comparable among the treatment groups, and vildagliptin was well-tolerated as add-on therapy to other OADs.

CONCLUSIONS

The evidence from the two studies indicates that vildagliptin as an add-on therapy to other OADs is a clinically reasonable option for Japanese patients with T2DM who respond inadequately to other OAD monotherapy.

Factor Analysis of Changes in Hemoglobin A1c After 12 Months of Sitagliptin Therapy in Patients With Type 2 Diabetes

Background

Sitagliptin, a dipeptidyl peptidase-4 inhibitor, is an effective oral antidiabetic agent as both monotherapy and when combined with insulin. Data from three observational studies performed in patients with type 2 diabetes receiving sitagliptin therapy in the routine clinical setting were integrated to conduct factor analysis of the changes in hemoglobin A1c (HbA1c), body weight, and estimated glomerular filtration rate (eGFR) over 12 months.

Methods

Among patients with type 2 diabetes attending medical institutions affiliated with Kanagawa Physicians Association, those using sitagliptin were followed for 1 year. In the ASSET-K and ASSIST-K studies, patients were managed by diabetologists, while they were managed by non-diabetologists in the ATTEST-K study. Patients were not administered insulin in ASSET-K, whereas insulin was administered in ASSIST-K. HbA1c (National Glycohemoglobin Standardization Program), blood glucose (fasting/postprandial), body weight, and renal function (serum creatinine and eGFR) were the efficacy endpoints. Factor analysis was performed by analysis of variance using the magnitude of the change in HbA1c, body weight, and eGFR after 12 months of sitagliptin therapy as response variables, and the study, sex, and age as explanatory variables.

Results

Of 1,327 patients registered in ASSET-K (diabetologists/without insulin), 1,167 patients in ASSIST-K (diabetologists/with insulin), and 530 patients in ATTEST-K (non-diabetologists), statistical analysis was carried out on 1,074, 854, and 411 patients, respectively. There were significant inter-study differences in patient characteristics (complications, duration of diabetes, and baseline HbA1c), the sitagliptin dose, and the use of other antidiabetic agents. HbA1c decreased significantly in all three studies. According to factor analysis, the magnitude of the change in HbA1c over 12 months showed significant inter-study differences and was also significantly influenced by the age, duration of diabetes, and baseline HbA1c.

Conclusions

Comparison of three observational studies identified differences in patient characteristics, treatment of diabetes (use/non-use of insulin), and the level of specialist care (diabetologist/non-diabetologist). Despite such differences, consistent reduction of HbA1c by sitagliptin was demonstrated in all three studies. The patients showing most improvement in HbA1c with sitagliptin therapy were older patients with a short duration of diabetes and high baseline HbA1c level.

Two-year assessment of the efficacy and safety of sitagliptin in elderly patients with type 2 diabetes: Post hoc analysis of the ASSET-K study

BACKGROUND

There have only been a few reports about use of dipeptidyl peptidase 4 (DPP-4) inhibitors in elderly patients with type 2 diabetes mellitus (T2DM), suggesting that the safety of these agents has not been sufficiently demonstrated. We performed a comparative review of the efficacy and safety of sitagliptin for Japanese patients with T2DM managed in the real-world clinical setting.

METHODS

An age-stratified analysis was performed of 831 patients who were treated with sitagliptin for 2 years. Parameters assessed included the hemoglobin A1c (HbA1c), body weight, serum creatinine, and adverse events. HbA1c and the incidence of hypoglycemia were also evaluated in patients treated with sitagliptin and a sulfonylurea (SU), who were divided into three age groups (<65 years, 65-74 years, and ≥75 years).

RESULTS

Comparison of glycemic control parameters, laboratory values, and adverse events revealed significant improvement of HbA1c, casual postprandial plasma glucose, and fasting plasma glucose in each age group with no change in body weight. Serum creatinine increased significantly in all age groups. Hypoglycemia only occurred in patients who received combined treatment with an SU and sitagliptin, and there was no age-related difference in its incidence.

CONCLUSIONS

HbA1c was improved by 2 years of sitagliptin therapy in all three age groups, and age did not seem to influence the incidence of hypoglycemic events. These results confirm the efficacy and safety of sitagliptin in patients ≥ 75 years old, suggesting that it is also useful for treating elderly patients with T2DM.

Factors Predicting Therapeutic Efficacy of Combination Treatment With Sitagliptin and Insulin in Type 2 Diabetic Patients: The ASSIST-K Study

Background

It is unclear whether dipeptidyl peptidase-4 inhibitors decrease hemoglobin A_1c (HbA_1c) in a glucose-dependent manner in patients on insulin therapy who have impaired insulin secretion. This study investigated factors influencing the efficacy of sitagliptin when used concomitantly with insulin to treat type 2 diabetes mellitus (T2DM) in the real-world setting.

Methods

A retrospective study was conducted of 1,004 T2DM patients at 36 Japanese clinics associated with the Diabetes Task Force of the Kanagawa Physicians Association. Eligible patients had been on insulin for at least 6 months, with a baseline HbA_1c of 7.0% (53 mmol/mol) or higher. Baseline characteristics and laboratory data from 495 patients were subjected to multiple regression analysis to identify factors influencing the change of HbA_1c.

Results

Most patients (n = 809) received sitagliptin at a dose of 50 mg. In the 1,004 patients, HbA_1c decreased by 0.74% (6 mmol/mol) and body weight increased by 0.1 kg after 6 months of combination therapy. Multiple regression analysis showed that a higher baseline HbA_1c, older age, and lower body mass index influenced the change of HbA_1c after 6 months. Hypoglycemic symptoms occurred in 7.4%, but none were severe.

Conclusions

These results emphasize the importance of a higher HbA_1c at the commencement of sitagliptin therapy in patients on insulin. Glucose-dependent suppression of glucagon secretion by sitagliptin may be useful in patients with impaired insulin secretion. Sitagliptin can be used concomitantly with insulin irrespective of the insulin regimen, duration of insulin treatment, and concomitant medications.

Effects of sitagliptin on the serum creatinine in Japanese type 2 diabetes

We found a slight elevation of serum creatinine in the subjects treated with sitagliptin for 2 years and a correlation between creatinine elevation and HbA1c reduction. These results suggest that creatinine elevation is associated with activation of incretin, most possibly with up-regulation of diuretic activity of GLP-1.

Role of Epac2A/Rap1 signaling in interplay between incretin and sulfonylurea in insulin secretion

Incretin-related drugs and sulfonylureas are currently used worldwide for the treatment of type 2 diabetes. We recently found that Epac2A, a cAMP binding protein having guanine nucleotide exchange activity toward Rap, is a target of both incretin and sulfonylurea. This suggests the possibility of interplay between incretin and sulfonylurea through Epac2A/Rap1 signaling in insulin secretion. In this study, we examined the combinatorial effects of incretin and various sulfonylureas on insulin secretion and activation of Epac2A/Rap1 signaling. A strong augmentation of insulin secretion by combination of GLP-1 and glibenclamide or glimepiride, which was found in Epac2A(+/+) mice, was markedly reduced in Epac2A(-/-) mice. In contrast, the combinatorial effect of GLP-1 and gliclazide was rather mild, and the effect was not altered by Epac2A ablation. Activation of Rap1 was enhanced by the combination of an Epac-selective cAMP analog with glibenclamide or glimepiride but not gliclazide. In diet-induced obese mice, ablation of Epac2A reduced the insulin secretory response to coadministration of the GLP-1 receptor agonist liraglutide and glimepiride. These findings clarify the critical role of Epac2A/Rap1 signaling in the augmenting effect of incretin and sulfonylurea on insulin secretion and provide the basis for the effects of combination therapies of incretin-related drugs and sulfonylureas.

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).

Sitagliptin: a review of its use in patients with type 2 diabetes mellitus

Sitagliptin (Januvia(®), Xelevia™, Glactiv(®), Tesavel(®)) is an orally administered, potent and highly selective inhibitor of dipeptidyl peptidase-4 (DPP-4) and was the first agent of its class to be approved for use in the management of adults with type 2 diabetes. Numerous randomized placebo- or active comparator-controlled trials have demonstrated the efficacy of sitagliptin in terms of improving glycaemic control in patients with type 2 diabetes, including its use as monotherapy, initial combination therapy (usually with fixed-dose combinations of sitagliptin/metformin), or add-on therapy to metformin or to other antihyperglycaemic drugs, with or without metformin. The primary endpoint of the clinical trials was the reduction from baseline in glycosylated haemoglobin (HbA1c), although sitagliptin also showed beneficial effects for other endpoints, such as the proportion of patients who achieved target HbA1c, and reductions from baseline in fasting plasma glucose (FPG) levels and 2-h postprandial glucose (PPG) levels. Sitagliptin was generally well tolerated in clinical trials, had a low risk of hypoglycaemia (although this depends on background therapy) and had a neutral effect on body weight. Despite concerns regarding a possible increased risk of rare pancreatic adverse events (e.g. pancreatitis) with glucagon-like peptide-1 (GLP-1)-based therapies, such as GLP-1 receptor agonists and DPP-4 inhibitors, no causal association has been found; regulators in Europe recently conducted a review of available data, concluding that there is little evidence that these drugs could cause pancreatic inflammation or pancreatic cancer. A similar review is planned in the USA and postmarketing surveillance will continue. Thus, oral sitagliptin is an effective and generally well tolerated treatment option for the management of patients with type 2 diabetes.

Glutamate acts as a key signal linking glucose metabolism to incretin/cAMP action to amplify insulin secretion

Incretins, hormones released by the gut after meal ingestion, are essential for maintaining systemic glucose homeostasis by stimulating insulin secretion. The effect of incretins on insulin secretion occurs only at elevated glucose concentrations and is mediated by cAMP signaling, but the mechanism linking glucose metabolism and cAMP action in insulin secretion is unknown. We show here, using a metabolomics-based approach, that cytosolic glutamate derived from the malate-aspartate shuttle upon glucose stimulation underlies the stimulatory effect of incretins and that glutamate uptake into insulin granules mediated by cAMP/PKA signaling amplifies insulin release. Glutamate production is diminished in an incretin-unresponsive, insulin-secreting β cell line and pancreatic islets of animal models of human diabetes and obesity. Conversely, a membrane-permeable glutamate precursor restores amplification of insulin secretion in these models. Thus, cytosolic glutamate represents the elusive link between glucose metabolism and cAMP action in incretin-induced insulin secretion.

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Glutamate is derived from the malate-aspartate shuttle upon glucose stimulation

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Shuttle-derived glutamate is crucial for incretin-induced insulin secretion

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Cytosolic glutamate is transported into insulin granules via cAMP/PKA signaling

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Glutamate production by glucose is defective in incretin-unresponsive β cells

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.

Secretory units of islets in transplantation index is a useful predictor of insulin requirement in Japanese type 2 diabetic patients

AIMS/INTRODUCTION

The objective of the present study was to clarify the validity of β-cell function-related parameters for predicting the insulin requirement of Japanese type 2 diabetic patients.

MATERIALS AND METHODS

In 188 patients with type 2 diabetes who had been admitted to the University of Toyama Hospital (Toyama, Japan) without receiving insulin therapy, we carried out a cross-sectional study examining the relationship between the homeostasis model assessment of β-cell function (HOMA-β) and C-peptide-based indices, and also carried out a retrospective study to examine the utility for predicting insulin requirement of several β -cell function-related indices using a receiver operating characteristic (ROC) curve analysis.

RESULTS

The secretory units of islets in transplantation index (SUIT) had the strongest correlation with HOMA-β, followed by the fasting serum C-peptide immunoreactivity index (CPI); the fasting serum C-peptide immunoreactivity itself (F-CPR) had the least correlation. The CPI, HOMA-β and SUIT were significantly lower in the insulin-requiring group than in the non-insulin-requiring group, even after adjustments for confounding factors (P < 0.01). The areas under the ROC curve for insulin requirement were 0.622, 0.774, 0.808, and 0.759 for F-CPR, CPI, SUIT, and HOMA-β, respectively. The cut-off values of SUIT, CPI, and HOMA-β for an over 80% specificity for the prediction of insulin therapy were 23.5, 1.00, and 14.9, respectively.

CONCLUSIONS

The present study shows that SUIT is the best predictor of insulin requirement among these β-cell function-related markers.

Sensory and motor physiological functions are impaired in gastric inhibitory polypeptide receptor-deficient mice

AIMS/INTRODUCTION

Gastric inhibitory polypeptide (GIP) is an incretin secreted from the gastrointestinal tract after an ingestion of nutrients, and stimulates an insulin secretion from the pancreatic islets. Additionally, GIP has important roles in extrapancreatic tissues: fat accumulation in adipose tissue, neuroprotective effects in the central nervous system and an inhibition of bone resorption. In the current study, we investigated the effects of GIP signaling on the peripheral nervous system (PNS).

MATERIALS AND METHODS

First, the presence of the GIP receptor (GIPR) in mouse dorsal root ganglion (DRG) was evaluated utilizing immunohistochemical analysis, western blotting and reverse transcription polymerase chain reaction. DRG neurons of male wild-type mice (WT) were cultured with or without GIP, and their neurite lengths were quantified. Functions of the PNS were evaluated in GIPR-deficient mice (gipr-/-) and WT by using current perception thresholds (CPTs), Thermal Plantar Test (TPT), and motor (MNCV) and sensory nerve conduction velocity (SNCV, respectively). Sciatic nerve blood flow (SNBF) and plantar skin blood flow (PSBF) were also evaluated.

RESULTS

We confirmed the expression of GIPR in DRG neurons. The neurite outgrowths of DRG neurons were promoted by the GIP administrations. The gipr-/- showed impaired perception functions in the examination of CPTs and TPT. Both MNCV and SNCV were delayed in gipr-/- compared with these in WT. There was no difference in SNBF and PSBF between WT and gipr-/-.

CONCLUSIONS

Our findings show that the GIP signal could exert direct physiological roles in the PNS, which might be directly exerted on the PNS.

Long-term efficacy and safety of sitagliptin in the treatment of Japanese Type 2 diabetes (ASSET-K1) to a target of HbA1c <7%

BACKGROUND

Few studies have investigated the factors related to improvement and maintenance of glycemic control with sitagliptin in Type 2 diabetes (T2D) patients.

AIM

To identify factors contributing to reaching and maintaining glycated hemoglobin (HbA1c) <7% with sitagliptin in Japanese T2D patients.

SUBJECTS AND METHODS

This study included 1327 patients who were: taking sitagliptin as monotherapy; switched to sitagliptin; or taking sitagliptin in combination therapy. At baseline and 1, 3, 6, and 12 months after starting sitagliptin, weight, body mass index (BMI), HbA1c, fasting plasma glucose (FPG), and post-prandial plasma glucose (PPG) were measured. The subjects were divided into a group that achieved HbA1c<7% at 12 months, a poor control group (HbA1c≥8% at 12 months), and a discontinued group. Multiple regression analysis was performed to identify factors contributing to long-term control and maintenance with sitagliptin treatment.

RESULTS

HbA1c decreased significantly from 8.0% at baseline to 7.3%, but weight was unchanged. FPG and PPG improved significantly. The HbA1c<7% group had a significantly higher age and a signifi cant ly lower BMI at baseline than the HbA1c≥8% group and the discontinued group. On multivariate regression analysis, baseline HbA1c, baseline BMI, and Δbody weight after 12 months were significantly related to HbA1c reduction. The most common adverse event was hypoglycemia, and the most common adverse event responsible for discontinuation was constipation.

CONCLUSIONS

HbA1c<7.0% was achieved in 31% of T2D patients who had poor control with conventional treatment. Weight management is important for maintaining good long-term control with sitagliptin.

Factors associated with reduced efficacy of sitagliptin therapy: analysis of 93 patients with type 2 diabetes treated for 1.5 years or longer

Background

Several studies have shown the effectiveness of sitagliptin, a dipeptidyl peptidase-4 inhibitor, for type 2 diabetes, with a hypoglycemic effect being demonstrated both when it is administered alone or in combination with other oral antidiabetic agents. However, there are few reports about its long-term efficacy, although medications for diabetes need to be effective over the long term. This study (as part of ASSET-K) aimed to investigate the efficacy and safety of sitagliptin when it was administered for 1.5 years or longer, and to explore factors associated with reduction of the therapeutic response.

Methods

Out of 375 patients treated with sitagliptin (50 mg/day) at Kanamori Diabetes Clinic between December 2009 and March 2012, 133 could be followed up for 72 weeks without interruption. After excluding 40 patients in whom the dosage and/or types of concomitant medications were modified during that period, the remaining 93 were included in this analysis. Clinical indices, such as blood glucose, HbA1c, and body weight, were investigated retrospectively. Compliance with diet and exercise therapy at 48 weeks was checked by a questionnaire.

Results

In the 93 patients analyzed (sitagliptin monotherapy, n = 9; combination therapy, n = 77; and switching from an alpha-glucosidase inhibitor or glinide, n = 7), hemoglobin A1c (HbA1c) showed a significant decrease after 24 weeks (7.70 ± 0.73% at baseline vs. 6.90 ± 0.55% at 24 weeks), but then showed a slight increase at 48 weeks. HbA1c was subsequently maintained in the same range with no significant changes until 72 weeks. A positive correlation was noted between the changes of HbA1c and body weight from 24 to 48 weeks. Compliance with diet and exercise therapy was worse in patients showing a ≥ 0.3% increase of HbA1c (n = 37) from 24 to 48 weeks than in the others (n = 56). Multiple logistic regression analysis showed that both factors were independent determinants of the increase of HbA1c from 24 weeks onward.

Conclusions

Sitagliptin showed good efficacy and safety when administered for 18 months as both monotherapy and combination therapy. Inadequate compliance with diet/exercise therapy and weight again may be associated with an increase of HbA1c over time during treatment with sitagliptin.

Efficacy and safety of sitagliptin as add-on therapy on glycemic control and blood glucose fluctuation in Japanese type 2 diabetes subjects ongoing with multiple daily insulin injections therapy

To assess the efficacy and safety of adding sitagliptin, an oral dipeptidyl peptidase-4 inhibitor, in subjects with type 2 diabetes inadequately controlled with multiple daily insulin injections therapy (MDI). HbA1c, 1,5-anhydroglucitol (1,5-AG), body mass index (BMI), insulin doses, six-point self-measured plasma glucose (SMPG) profiles were assessed before, after 12 weeks, and after 24 weeks of MDI with 50 mg/day of sitagliptin in 40 subjects with type 2 diabetes. Safety endpoints included hypoglycemia and any adverse events. HbA1c significantly decreased during the first 12 weeks ( -0.64±0.60%), and was sustained over 24 weeks ( -0.69±0.85%). 1,5-AG increased significantly from 7.5±4.5 μg/mL at baseline to 9.6±5.5 μg/mL after 24 weeks. The bolus insulin dose at 12 weeks was decreased, and the mean plasma glucose, the SD of daily glucose, M-value, and the mean amplitude of glycemic excursions (MAGE) also decreased significantly as compared with baseline values. BMI and frequency of hypoglycemia were not changed significantly. Univariate linear regression analyses revealed that % change in HbA1c was significantly associated with BMI, and % changes in the indexes of glycemic instability (SD of daily glucose and MAGE) were significantly associated with age. In conclusion, adding sitagliptin to MDI significantly improved glycemic control and decreased the daily glucose fluctuation in subjects with type 2 diabetes inadequately controlled with MDI, without weight gain or an increase in the incidence of hypoglycemia. This trial was registered with UMIN (no. UMIN000010157).

Pleiotropic effects of sitagliptin in the treatment of type 2 diabetes mellitus patients

BACKGROUND

Sitagliptin is a DPP-4 inhibitor that became available for use in Japan three years ago. This study was conducted to identify the pleiotropic effects of sitagliptin other than blood glucose lowering in Japanese type 2 diabetes mellitus patients.

METHODS

A retrospective, observational study of 940 type 2 diabetes mellitus patients was conducted. The primary outcome measures were HbA1c, blood pressure, and lipid profiles measured at 0, 4, and 12 weeks of sitagliptin therapy.

RESULTS

After 12 weeks of sitagliptin treatment, compared with baseline, HbA1c decreased 0.64% ± 0.86%; systolic blood pressure (SBP) and diastolic blood pressure (DBP) decreased significantly; and serum creatinine (Cr) and uric acid (UA) levels were mildly but significantly elevated. A correlation analysis of the changes in systolic blood pressure, diastolic blood pressure, creatinine, and uric acid (ΔSBP, ΔDBP, ΔCr, ΔUA) from baseline to 12 weeks showed significant negative correlations between ΔSBP and ΔCr, ΔSBP and ΔUA, and ΔDBP and ΔCr. Total cholesterol and postprandial triglycerides were significantly decreased at both 4 and 12 weeks. Alkaline phosphatase (ALP) decreased significantly, and there was a significant positive correlation between changes in ALP and HbA1c.

CONCLUSIONS

Sitagliptin seems to be effective not only in lowering blood glucose but also in lowering blood pressure, lipid, and ALP levels. Sitagliptin appears to contribute to a Na-diuretic action due to GLP-1.