A Double-Blind, Randomized, Placebo and Positive-Controlled Study in Healthy Volunteers to Evaluate Pharmacokinetic and Pharmacodynamic Properties of Multiple Oral Doses of Cetagliptin

Advances in small-molecule insulin secretagogues for diabetes treatment

Diabetes, a metabolic disease caused by abnormally high levels of blood glucose, has a high prevalence rate worldwide and causes a series of complications, including coronary heart disease, stroke, peripheral vascular disease, end-stage renal disease, and retinopathy. Small-molecule compounds have been developed as drugs for the treatment of diabetes because of their oral advantages. Insulin secretagogues are a class of small-molecule drugs used to treat diabetes, and include sulfonylureas, non-sulfonylureas, glucagon-like peptide-1 receptor agonists, dipeptidyl peptidase 4 inhibitors, and other novel small-molecule insulin secretagogues. However, many small-molecule compounds cause different side effects, posing huge challenges to drug monotherapy and drug selection. Therefore, the use of different small-molecule drugs must be improved. This article reviews the mechanism, advantages, limitations, and potential risks of small-molecule insulin secretagogues to provide future research directions on small-molecule drugs for the treatment of diabetes.

Safety, tolerability, pharmacokinetics and pharmacokinetic-pharmacodynamic modeling of cetagliptin in patients with type 2 diabetes mellitus

Aims

To evaluate the safety, tolerability, pharmacokinetics (PK), and pharmacodynamics (PD) of cetagliptin (CAS number:2243737-33-7) in Chinese patients with type 2 diabetes mellitus (T2DM). A population PK/PD model was developed to quantify the PK and PD characteristics of cetagliptin in patients.

Materials and methods

32 Chinese adults with T2DM were enrolled in this study. The subjects were randomly assigned to receive either cetagliptin (50 mg or 100 mg), placebo, or sitagliptin (100 mg) once daily for 14 days. Blood samples were collected for PK and PD analysis. Effects on glucose, insulin, C-peptide, and glucagon were evaluated following an oral glucose tolerance test (OGTT) (day15). Effects on HbA1c and glycated albumin (GA), and safety assessments were also conducted. Meanwhile, a population PK/PD model was developed by a sequential two-step analysis approach using Phoenix.

Results

Following multiple oral doses, cetagliptin was rapidly absorbed and the mean half-life were 34.9-41.9 h. Steady-state conditions were achieved after 1 week of daily dosing and the accumulation was modest. The intensity and duration of DPP-4 inhibition induced by 50 mg cetagliptin were comparable with those induced by sitagliptin, and 100 mg cetagliptin showed a much longer sustained DPP-4 inhibition (≥80%) than sitagliptin. Compared with placebo group, plasma active GLP-1 AUEC0-24h increased by 2.20- and 3.36-fold in the 50 mg and 100 mg cetagliptin groups. A decrease of plasma glucose and increase of insulin and C-peptide were observed following OGTT in cetagliptin groups. Meanwhile, a tendency of reduced GA was observed, whereas no decreasing trend was observed in HbA1c. All adverse events related to cetagliptin and sitagliptin were assessed as mild. A population PK/PD model was successfully established. The two-compartment model and Sigmoid-Emax model could fit the observed data well. Total bilirubin (TBIL) was a covariate of volume of peripheral compartment distribution (V2), and V2 increased with the increase of TBIL.

Conclusions

Cetagliptin was well tolerated, inhibited plasma DPP-4 activity, increased plasma active GLP-1 levels, and exhibited a certain trend of glucose-lowering effect in patients with T2DM. The established population PK/PD model adequately described the PK and PD characteristics of cetagliptin.

A randomized, double-blind, placebo controlled, phase 3 trial to evaluate the efficacy and safety of cetagliptin added to ongoing metformin therapy in patients with uncontrolled type 2 diabetes with metformin monotherapy

AIM

This trial was designed to assess the efficacy and safety of cetagliptin added to metformin in Chinese patients with type 2 diabetes who had inadequate glycaemic control with metformin monotherapy.

METHODS

In total, 446 patients with type 2 diabetes on metformin monotherapy were randomized to receive the addition of once-daily cetagliptin 100 mg, cetagliptin 50 mg and placebo in a 2:2:1 ratio for 24-week double-blind treatment. At week 24, patients initially randomized to cetagliptin 50 mg and placebo were switched to cetagliptin 100 mg for 28 weeks open-label treatment. The primary endpoint was the change in haemoglobin A1c (HbA1c) from baseline, and the efficacy analyses were based on an all-patients-treated population using an analysis of co-variance.

RESULTS

After 24 weeks, both add-on therapies led to greater glycaemic control. Reductions in HbA1c from baseline were -1.17 ± 0.794%, -1.23 ± 0.896% in cetagliptin 100 mg and 50 mg plus metformin group, respectively. No difference was observed between the cetagliptin 100 mg and 50 mg plus metformin group. Patients with higher baseline HbA1c levels (≥8.5%) experienced greater reductions in HbA1c. A significantly greater proportion of patients achieved an HbA1c <7.0% with cetagliptin 100 mg (49.4%) and cetagliptin 50 mg (51.1%) plus metformin than metformin monotherapy (14.4%). Both combination therapies also improved the homeostasis model assessment β-function index and decreased systolic blood pressure. There was no increased risk of adverse effects with combination therapy, and both combination therapies were generally well tolerated.

CONCLUSIONS

The addition of cetagliptin once daily to metformin was more efficacious and well tolerated than metformin monotherapy in Chinese patients with type 2 diabetes who had inadequate glycaemic control with metformin monotherapy.

Efficacy and safety of cetagliptin as monotherapy in patients with type 2 diabetes: A randomized, double-blind, placebo-controlled phase 3 trial

AIM

To assess the efficacy and safety of the dipeptidyl peptidase-4 inhibitor, cetagliptin, as monotherapy in Chinese patients with type 2 diabetes (T2D) and inadequate glycaemic control.

MATERIALS AND METHODS

In total, 504 eligible patients with T2D were enrolled and randomized to cetagliptin 50 mg once daily, cetagliptin 100 mg once daily or placebo at a ratio of 2:2:1 for 24 weeks of double-blind treatment, then all patients received cetagliptin 100 mg once daily for 28 weeks of open-label treatment. The primary efficacy endpoint was the change in HbA1c level from baseline at week 24.

RESULTS

After 24 weeks, HbA1c from baseline was significantly reduced with cetagliptin 50 mg (-1.08%) and cetagliptin 100 mg (-1.07%) compared with placebo (-0.35%). The placebo-subtracted HbA1c reduction was -0.72% with cetagliptin 50 mg and 100 mg. Patients with a baseline HbA1c of 8.5% or higher had a greater HbA1c reduction with cetagliptin than those patients with a baseline HbA1c of less than 8.5%. Both doses studied led to a significantly higher proportion of patients (42.3% with 100 mg and 45.0% with 50 mg) achieving an HbA1c of less than 7.0% compared with placebo (12.9%). Cetagliptin also significantly lowered fasting plasma glucose and 2-hour postmeal plasma glucose relative to placebo. The incidence of adverse experiences was similar between cetagliptin and placebo. No drug-related hypoglycaemia was reported.

CONCLUSIONS

Cetagliptin monotherapy was effective and well tolerated in Chinese patients with T2D who had inadequate glycaemic control on exercise and diet.

Tirzepatide: A Systematic Update

Tirzepatide is a new molecule capable of controlling glucose blood levels by combining the dual agonism of Glucose-Dependent Insulinotropic Polypeptide (GIP) and Glucagon-Like Peptide-1 (GLP-1) receptors. GIP and GLP1 are incretin hormones: they are released in the intestine in response to nutrient intake and stimulate pancreatic beta cell activity secreting insulin. GIP and GLP1 also have other metabolic functions. GLP1, in particular, reduces food intake and delays gastric emptying. Moreover, Tirzepatide has been shown to improve blood pressure and to reduce Low-Density Lipoprotein (LDL) cholesterol and triglycerides. Tirzepatide efficacy and safety were assessed in a phase III SURPASS 1-5 clinical trial program. Recently, the Food and Drug Administration approved Tirzepatide subcutaneous injections as monotherapy or combination therapy, with diet and physical exercise, to achieve better glycemic blood levels in patients with diabetes. Other clinical trials are currently underway to evaluate its use in other diseases. The scientific interest toward this novel, first-in-class medication is rapidly increasing. In this comprehensive and systematic review, we summarize the main results of the clinical trials investigating Tirzepatide and the currently available meta-analyses, emphasizing novel insights into its adoption in clinical practice for diabetes and its future potential applications in cardiovascular medicine.

Disposition study of the novel dipeptidyl peptidase 4 inhibitor cetagliptin in rats

Dipeptidyl peptidase-4 (DPP-4) inhibitor is a class of oral antihyperglycemic agents and therapeutic approach for type 2 diabetes. Cetagliptin is a novel oral and selective DPP-4 inhibitor and developed as a promising candidate for treatment of type 2 diabetes mellitus.This study aimed to evaluate the metabolism and excretion of cetagliptin in Sprague-Dawley (SD) rats, and to detect and identify metabolites of cetagliptin.The SD rats were administered with a single oral dose of 6 mg/kg with approximately 100 µCi of [¹⁴C] cetagliptin. The mean total recovery of radioactivity was 90.20% within 168h in SD rats excreta. Cetagliptin was the major radioactive component in SD rats plasma, urine and eliminated primarily by faecal excretion. The recovery of cetagliptin in urine and feces was 25.15% and 13.85% of the dose, respectively. Cetagliptin was well absorbed after oral administration in SD rats based on the total recovery of radioactivity in BDC SD rats bile and urine.Six major metabolites were observed and identified in SD rats, comprising 0.20 to 4.53% of total plasma AUC. These major metabolites were the hydroxylated, N-sulphate and N-carbamoyl glucuronic acid conjugates of the cetagliptin, two metabolites formed by glucuronide of a hydroxylated metabolite.