Gemigliptin Improves Salivary Gland Dysfunction in D-Galactose-Injected Aging Rats

Oral dryness is among the most common conditions experienced by the elderly. As saliva plays a crucial role in maintaining oral health and overall quality of life, the condition is increasingly taking its toll on a rapidly growing aging population. D-galactose (D-gal) stimulates their formation, which in turn cause oxidative stress and accelerate age-related decline in physical function. In this study, we observed a reduction in salivary secretion and amylase levels in aged rats injected with D-gal, confirming salivary gland dysfunction. Treatment with gemigliptin increased DPP-4 inhibition and GLP-1 levels in the salivary glands of aging rats and reduced the expression of AGEs and receptors for advanced glycation end products (RAGE). This effect was caused by the presence of additional reactive oxygen species (ROS) in the salivary glands of the examined rats. Gemigliptin's cytoprotective effect reduced amylase and mucin accumulation and increased AQP5 expression, which are important indicators of salivary gland function. In sum, gemigliptin was shown to improve D-gal-induced decline in the salivary gland function of aged rats through its anti-glycation and antioxidant activities. Gemigliptin shows promise as a treatment strategy for patients experiencing decreased salivary function associated with their advancing age.

The effect of gemigliptin treatment on immune parameters including regulatory T cells in patients with type 2 diabetes and moderate to very severe chronic renal impairment

It is crucial to understand the impact of DPP-4 inhibitors on the immune system, particularly T cell differentiation, maturation, and proliferation, in patients with type 2 diabetes and CKD. This prospective observational study aimed to investigate the distribution of immune cells (particularly regulatory T cells), following the administration of gemigliptin, a DPP-4 inhibitor, in patients with type 2 diabetes mellitus and chronic kidney disease. We enrolled 28 patients with type 2 diabetes, aged 20 to 69, who had been taking a daily dose of 50mg gemigliptin for <3 months and had chronic kidney disease stages 3, 4, or 5, including that undergoing dialysis. T regulatory cells were defined as CD4 + CD25 high CD127 low/- FoxP3 + phenotype, and flow cytometry was used to examine the distribution of T regulatory cells. In the patient group, blood samples were collected at baseline, as well as at 3 and 6 months after initiating medication. Of the 28 patients, 17 (60.7%) were male and the mean age was 61.82 ± 8.03 years. Serum Cr ≥ 1.5 mg/dL was 16 (57%), and Cr < 1.5 mg/dL was 12 (43%). The number of CD4(+)/CD25(+) cells did not significantly increase or decrease in baseline, 3 months, and 6 months time changes, and the number of CD127(-/FoxP3(+) cells did not change significantly. Treatment with gemigliptin for 3 and 6 months did not significantly alter the number, percentage, or ratio of circulating Treg cells in patients with type 2 diabetes and CKD. Therefore, the administration of gemigliptin may help maintain regulatory T cells or have no significant impact.

Pseudo-pheochromocytoma due to obstructive sleep apnea: a case report

SUMMARY

Obstructive sleep apnea (OSA) is a condition of intermittent nocturnal upper airway obstruction. OSA increases sympathetic drive which may result in clinical and biochemical features suggestive of pheochromocytoma. We present the case of a 65-year-old male with a 2.9-cm left adrenal incidentaloma on CT, hypertension, symptoms of headache, anxiety and diaphoresis, and persistently elevated 24-h urine norepinephrine (initially 818 nmol/day (89-470)) and normetanephrine (initially 11.2 µmol/day (0.6-2.7)). He was started on prazosin and underwent left adrenalectomy. Pathology revealed an adrenal corticoadenoma with no evidence of pheochromocytoma. Over the next 2 years, urine norepinephrine and normetanephrine remained significantly elevated with no MIBG avid disease. Years later, he was diagnosed with severe OSA and treated with continuous positive airway pressure. Urine testing done once OSA was well controlled revealed complete normalization of urine norepinephrine and normetanephrine with substantial symptom improvement. It was concluded that the patient never had a pheochromocytoma but rather an adrenal adenoma with biochemistry and symptoms suggestive of pheochromocytoma due to untreated severe OSA. Pseudo-pheochromocytoma is a rare presentation of OSA and should be considered on the differential of elevated urine catecholamines and metanephrines in the right clinical setting.

LEARNING POINTS

Obstructive sleep apnea (OSA) is a common condition among adults. OSA may rarely present as pseudo-pheochromocytoma with symptoms of pallor, palpitations, perspiration, headache, or anxiety. OSA should be considered on the differential of elevated urine catecholamines and metanephrines, especially in patients with negative metaiodobenzylguanidine (MIBG) scan results.

Efficacy and safety of gemigliptin as add-on therapy to insulin, with or without metformin, in patients with type 2 diabetes mellitus (ZEUS II study)

The objective of this study was to evaluate the efficacy and safety of gemigliptin added to a stable dose of insulin alone or of insulin in combination with metformin in patients with type 2 diabetes mellitus. After a two-week run-in period, patients were randomized 2:1 to receive gemigliptin 50 mg or placebo once daily as add-on to background therapy with insulin or insulin plus metformin for 24 weeks. The primary endpoint was change in haemoglobin A1c (HbA1c) from baseline at Week 24. Baseline characteristics were similar between the gemigliptin (n = 188) and placebo (n = 95) groups in terms of HbA1c (8.1%). At Week 24, the gemigliptin group showed a statistically significant reduction in mean HbA1c from baseline as compared with placebo (between-group mean difference, -0.7% [95% CI, -0.9% to -0.4%]; P-value < 0.0001). The incidence of overall adverse events and the number of hypoglycaemic adverse events were similar between the study groups. Gemigliptin added to insulin alone or to insulin in combination with metformin resulted in superior glycaemic control compared to that in the placebo group and was well tolerated for 24 weeks in patients with type 2 diabetes mellitus, without causing weight gain or increasing the incidence of hypoglycaemia.

Pharmacokinetic Interactions Between Gemigliptin and Metformin, and Potential Differences in the Pharmacokinetic Profile of Gemigliptin Between the Mexican and Korean Populations: A Randomized, Open-label Study in Healthy Mexican Volunteers

PURPOSE

The aim of this study was to assess the pharmacokinetic interactions between a newly developed dipeptidyl peptidase (DPP)-4 inhibitor, gemigliptin, and metformin in healthy Mexican male volunteers, and the differences in the pharmacokinetic profile of gemigliptin between Korean and Mexican healthy volunteers.

METHODS

This was a multiple-dose, randomized, open-label, 3-way, 3-period crossover study. Subjects were randomized to 1 of 3 treatment sequences and received gemigliptin 50mg once a day, metformin1000mg BID, or both drugs during a 7-day treatment period, and underwent sampling for pharmacokinetic analysis and tolerability assessments. Point estimates and 90% CIs of C_max,ss and AUCτ,ss least squares mean (LSM) ratios of the concurrent administration of gemigliptin + metformin to the administration of monotherapy with either drug were obtained, and the pharmacokinetic profile of gemigliptin observed was compared with that in healthy Korean volunteers studied during the initial development of gemigliptin.

FINDINGS

The coadministration of gemigliptin + metformin did not affect the pharmacokinetic characteristics of gemigliptin (LSM ratio [90% CI] for C_max,ss and AUC_τ,ss: 0.98 [0.87-1.10] and 0.94 [0.91-0.98], respectively) or metformin (LSM ratio [90% CI] for C_max,ss and AUC_τ,ss: 0.97 [0.88-1.08] and 1.02 [0.93-1.12], respectively) when administered as monotherapy and was well tolerated. In contrast with Korean healthy volunteers, Mexican subjects showed a modestly higher gemigliptin exposure (LSM ratio [90% CI] for AUC_τ,ss: 1.22 [1.14-1.31]).

IMPLICATIONS

The results of this study support, in ethnically different populations, the absence of drug-drug interactions between gemigliptin and metformin previously shown in Korean healthy volunteers. Considering the flat effect-concentration curve and wide therapeutic range of gemigliptin, the pharmacokinetic profile of gemigliptin observed in healthy Mexican and Korean subjects suggests that gemigliptin use in Mexican patients may be associated with outcomes, in terms of efficacy and tolerability, similar to those observed in the Korean population. ClinicalTrials.gov identifier: NCT03310749.

A 52-week extension study of switching from gemigliptin vs sitagliptin to gemigliptin only as add-on therapy for patients with type 2 diabetes who are inadequately controlled with metformin alone

We investigated the long-term efficacy and safety of gemigliptin and the efficacy and safety of gemigliptin treatment after once-daily treatment with sitagliptin 100 mg, in patients with type 2 diabetes. This was a 28-week extension of a 24-week, randomized, double-blind, parallel study of gemigliptin or sitagliptin added to ongoing metformin therapy. After randomization to sitagliptin 100 mg qd (S), gemigliptin 25 mg bid (G1) or gemigliptin 50 mg qd (G2) and after completing 24 weeks of treatment, 118 patients switched from gemigliptin 25 mg bid to 50 mg qd (G1/G2), 111 patients continued gemigliptin 50 mg qd (G2/G2) and 106 patients switched from sitagliptin 100 mg qd to gemigliptin 50 mg qd (S/G2). All 3 treatments reduced glycated haemoglobin (HbA1c) (S/G2,-0.99% [95% CI -1.25%, -0.73%]; G1/G2, -1.11% [95% CI -1.33%, -0.89%]; G2/G2, -1.06% [95% CI -1.28%, -0.85%]). The percentage of patients achieving HbA1c < 6.5% was 27.6% in the G1/G2 group at both Week 24 and Week 52, and ranged from 27.3% to 32.7% in the G2/G2 group (difference in proportions, 5% [95% CI -6%, 17%]), while it increased from 6.8% to 27.3% from Week 24 to Week 52 in the S/G2 group (difference in proportions, 20% [95% CI 7%, 34%]). Addition of gemigliptin 50 mg qd to metformin was shown to be efficacious for 52 weeks. Switching from sitagliptin 100 mg to gemigliptin 50 mg showed consistent glyacemic control over the previous treatment.

Gemigliptin: Newer Promising Gliptin for Type 2 Diabetes Mellitus

The dipeptidyl peptidase-4 (DPP-4) inhibitors have facilitated the management of type 2 diabetes mellitus (T2DM) owing to their superior efficacy and safety with low incidence of adverse effects. Gemigliptin is a new member of this family of drugs, and studies have revealed certain advantages of gemigliptin use compared to its previous congeners. Besides, this drug has also been studied for the treatment of T2DM as monotherapy, in combination with metformin or other oral antidiabetic drugs and in T2DM with moderate-to-severe renal failure. In this review, we explore the published data highlighting the pharmacology, efficacy, and safety of gemigliptin along with its recommendations for use in patients with T2DM.

Effect of gemigliptin on glycaemic variability in patients with type 2 diabetes (STABLE study)

The aim of this study was to evaluate the effect of gemigliptin vs sitagliptin or glimepiride as initial combination therapy with metformin on glycaemic variability and to assess the correlation between glycaemic variability reduction and the dipeptidyl peptidase-4 (DPP-4) inhibition in patients with type 2 diabetes. This multicentre, randomized, active-controlled, open-label exploratory study included 69 patients with HbA1c > 7.5%. Subjects were randomized to receive gemigliptin 50 mg (n = 24), sitagliptin 100 mg (n = 23) or glimepiride 2 mg (n = 22) for 12 weeks. After 12 weeks, the change in mean amplitude of glycaemic excursion (MAGE) compared with baseline was significantly lower in the DPP-4 inhibitor groups compared with that in patients who received glimepiride. Furthermore, the standard deviation (SD) of glucose was significantly lower in patients who received gemigliptin than that in patients who received sitagliptin or glimepiride. The DPP-4 inhibition was significantly correlated with changes in MAGE and SD of glucose. In conclusion, gemigliptin and sitagliptin were more effective than glimepiride in reducing glycaemic variability as initial combination therapy with metformin in patients with type 2 diabetes, and the DPP-4 inhibition was associated with a reduction in glycaemic variability.

An update on DPP-4 inhibitors in the management of type 2 diabetes

INTRODUCTION

DPP-4 inhibitors are a class of compounds used for the treatment of type 2 diabetes. The drugs inhibit the degradation of GLP-1, thus amplifying the incretin effect. They have moderate glycemic efficacy, a low propensity of causing hypoglycaemia and are weight neutral. The drugs are often used as second line therapy after metformin. Areas covered: This review summarizes the available compounds in the market and discusses the novel compounds that are currently under development. Several large cardiovascular outcome trials with some of the compounds have been completed, and their results and implications are considered. Fixed dose combination pills are currently the main focus of research and the contribution of these to the care of patients with diabetes is further discussed. Expert opinion: The DPP-4 inhibitors have been a successful class in drug development for diabetes. Taken orally and available as fixed dose combinations with metformin or with SGLT-2 inhibitors, they have reached a large market share of over 7 billion dollars. Other than retagliptin, it does not appear that any additional compound will be launched soon. Currently, the main focus is on the development of additional fixed dose combinations with SGLT-2 inhibitors, but the success of these combinations remains to be seen.

Clinical pharmacology of dipeptidyl peptidase 4 inhibitors indicated for the treatment of type 2 diabetes mellitus

Dipeptidyl peptidase-4 (DPP-4) inhibitors are a class of oral antidiabetic drugs that improve glycaemic control without causing weight gain or increasing hypoglycaemic risk in patients with type 2 diabetes mellitus (T2DM). The eight available DPP-4 inhibitors, including alogliptin, anagliptin, gemigliptin, linagliptin, saxagliptin, sitagliptin, teneligliptin, and vildagliptin, are small molecules used orally with identical mechanism of action and similar safety profiles in patients with T2DM. DPP-4 inhibitors may be used as monotherapy or in double or triple combination with other oral glucose-lowering agents such as metformin, thiazolidinediones, or sulfonylureas. Although DPP-4 inhibitors have the same mode of action, they differ by some important pharmacokinetic and pharmacodynamic properties that may be clinically relevant in some patients. The main differences between the eight gliptins include: potency, target selectivity, oral bioavailability, elimination half-life, binding to plasma proteins, metabolic pathways, formation of active metabolite(s), main excretion routes, dosage adjustment for renal and liver insufficiency, and potential drug-drug interactions. The off-target inhibition of selective DPP-4 inhibitors is responsible for multiorgan toxicities such as immune dysfunction, impaired healing, and skin reactions. As a drug class, the DPP-4 inhibitors have become accepted in clinical practice due to their excellent tolerability profile, with a low risk of hypoglycaemia, a neutral effect on body weight, and once-daily dosing. It is unknown if DPP-4 inhibitors can prevent disease progression. More clinical studies are needed to validate the optimal regimens of DPP-4 inhibitors for the management of T2DM when their potential toxicities are closely monitored.

Comparative review of dipeptidyl peptidase-4 inhibitors and sulphonylureas

Type 2 diabetes (T2DM) is a progressive disease, and pharmacotherapy with a single agent does not generally provide durable glycaemic control over the long term. Sulphonylurea (SU) drugs have a history stretching back over 60 years, and have traditionally been the mainstay choice as second-line agents to be added to metformin once glycaemic control with metformin monotherapy deteriorates; however, they are associated with undesirable side effects, including increased hypoglycaemia risk and weight gain. Dipeptidyl peptidase (DPP)-4 inhibitors are, by comparison, more recent, with the first compound being launched in 2006, but the class now globally encompasses at least 11 different compounds. DPP-4 inhibitors improve glycaemic control with similar efficacy to SUs, but do not usually provoke hypoglycaemia or weight gain, are relatively free from adverse side effects, and have recently been shown not to increase cardiovascular risk in large prospective safety trials. Because of these factors, DPP-4 inhibitors have become an established therapy for T2DM and are increasingly being positioned earlier in treatment algorithms. The present article reviews these two classes of oral antidiabetic drugs (DPP-4 inhibitors and SUs), highlighting differences and similarities between members of the same class, as well as discussing the potential advantages and disadvantages of the two drug classes. While both classes have their merits, the choice of which to use depends on the characteristics of each individual patient; however, for the majority of patients, DPP-4 inhibitors are now the preferred choice.

Effect of renal impairment and haemodialysis on the pharmacokinetics of gemigliptin (LC15-0444)

This study evaluated the effects of renal impairment (RI) and haemodialysis (HD) on the pharmacokinetics of gemigliptin, a novel dipeptidyl peptidase-4 (DPP-4) inhibitor. After a 100 mg administration to subjects with normal renal function (n = 23) or RI (n = 24), plasma, urine or dialysate samples were analysed. Control subjects were matched to patients based on age, gender and body mass index. Patients with mild, moderate, severe RI and end-stage renal disease (ESRD) showed 1.20, 2.04, 1.50 and 1.66-fold (1.10, 1.49, 1.22 and 1.21-fold) increase of mean area under the time-plasma concentration curve from 0 to infinity (AUCinf) [maximum plasma concentration (Cmax)] of gemigliptin, respectively. Pharmacokinetics of gemigliptin was comparable between HD and non-HD periods in ESRD patients. Less than 4% of the dose was removed by 4 h HD. RI appeared to have modest effect on the gemigliptin disposition. No dose adjustment in patients with RI is proposed on the basis of exposure-response relationship. Impact of HD on the removal of gemigliptin was negligible.

Absorption, distribution, metabolism and excretion of gemigliptin, a novel dipeptidyl peptidase IV inhibitor, in rats

1. The absorption, distribution, metabolism and excretion of a novel dipeptidyl peptidase IV inhibitor, gemigliptin, were examined following single oral administration of (14)C-labeled gemigliptin to rats. 2. The (14)C-labeled gemigliptin was rapidly absorbed after oral administration, and its bioavailability was 95.2% (by total radioactivity). Distribution to specific tissues other than the digestive organs was not observed. Within 7 days after oral administration, 43.6% of the administered dose was excreted via urine and 41.2% was excreted via feces. Biliary excretion of the radioactivity was about 17.7% for the first 24 h. After oral administration of gemigliptin to rats, the in vivo metabolism of gemigliptin was investigated with bile, urine, feces, plasma and liver samples. 3. The major metabolic pathway was hydroxylation, and the major circulating metabolites were a dehydrated metabolite (LC15-0516) and hydroxylated metabolites (LC15-0635 and LC15-0636).