Effects of piragliatin, a glucokinase activator, on fasting and postprandial plasma glucose in patients with type 2 diabetes mellitus

Recent drug development of dorzagliatin, a new glucokinase activator, with the potential to treat Type 2 diabetes: A review study

Type 2 diabetes mellitus (T2DM) is a complicated disease related to metabolism that results from resistance to insulin and sustained hyperglycemia. Traditional antidiabetic drugs cannot meet the demand of different diabetes patients for reaching the glycemic targets; thus, the identification of new antidiabetic drugs is urgently needed for the treatment of T2DM to enhance glycemic control and the prognosis of patients suffering from T2DM. Recently, glucokinase (GK) has attracted much attention and is considered to be an effective antidiabetic agent. Glucokinase activators (GKA) represented by dorzagliatin could activate GK and mimic its function that triggers a counter-regulatory response to blood glucose changes. Dorzagliatin has shown great potential for glycemic control in diabetic patients in a randomized, double-blind, placebo-controlled Phase 3 trial (SEED study) and had a favorable safety profile and was well tolerated (DAWN study). In the SEED study, dorzagliatin significantly reduced glycosylated hemoglobin (HbA1c) by 1.07% and postprandial blood glucose by 2.83 mol/L, showing the great potential of this drug to control blood glucose in diabetic patients, with good safety and good tolerance. An extension of the SEED study, the DREAM study, confirmed that dorzagliatin monotherapy significantly improved 24-h glucose variability and increased time in range (TIR) to 83.7% over 46 weeks. Finally, the clinical study of dorzagliatin combined with metformin (DAWN study) confirmed that dorzagliatin could significantly reduce HbA1c by 1.02% and postprandial blood glucose by 5.45 mol/L. The current review summarizes the development of GK and GKA, as well as the prospects, trends, applications, and shortcomings of these treatments, especially future directions of clinical studies of dorzagliatin.

Should Glucokinase be Given a Chance in Diabetes Therapeutics? A Clinical-Pharmacological Review of Dorzagliatin and Lessons Learned So Far

Despite advances in the management of type 2 diabetes mellitus (T2DM), one-third of patients with diabetes do not achieve the desired glycemic goal. Considering this inadequacy, many agents that activate glucokinase have been investigated over the last two decades but were withdrawn before submission for marketing permission. Dorzagliatin is the first glucokinase activator that has been granted approval for T2DM, only in China. As overstimulation of glucokinase is linked with pathophysiological disturbances such as fatty liver and cardiovascular issues and a loss of therapeutic efficacy with time. This review aims to highlight the benefits of glucokinase activators vis-à-vis the risks associated with chronic enzymatic activation. We discuss the multisystem disturbances expected with chronic activation of the enzyme, the lessons learned with glucokinase activators of the past, the major efficacy and safety findings with dorzagliatin and its pharmacological properties, and the status of other glucokinase activators in the pipeline. The approval of dorzagliatin in China was based on the SEED and the DAWN trials, the major pivotal phase III trials that enrolled patients with T2DM with a mean glycosylated hemoglobin of 8.3-8.4%, and a mean age of 53-54.5 years from multiple sites in China. Patients with uncontrolled diabetes, cardiac diseases, organ dysfunction, and a history of severe hypoglycemia were excluded. Both trials had a randomized double-blind placebo-controlled phase of 24 weeks followed by an open-label phase of 28 weeks with dorzagliatin. Drug-naïve patients with T2DM with a disease duration of 11.7 months were enrolled in the SEED trial while the DAWN trial involved patients with T2DM with a mean duration of 71.5 months and receiving background metformin therapy. Compared with placebo, the decline in glycosylated hemoglobin at 24 weeks was more with dorzagliatin with an estimated treatment difference of - 0.57% in the SEED trial and - 0.66% in the DAWN trial. The desired glycosylated hemoglobin (< 7%) was also attained at more than two times higher rates with dorzagliatin. The glycemic improvement was sustained in the SEED trial but decreased over 52 weeks in the DAWN trial. Hyperlipidemia was observed in 12-14% of patients taking dorzagliatin versus 9-11% of patients receiving a placebo. Additional adverse effects noticed over 52 weeks with dorzagliatin included an elevation in liver enzymes, hyperuricemia, hyperlacticacidemia, renal dysfunction, and cardiovascular disturbances. Considering the statistically significant improvement in glycosylated hemoglobin with dorzagliatin in patients with T2DM, the drug may be given a chance in treatment-naïve patients with a shorter disease history. However, with the waning therapeutic efficacy witnessed in patients with long-standing diabetes, which was also one of the potential concerns with previously tested molecules, extended studies involving patients with chronic and uncontrolled diabetes are needed to comment upon the long-term therapeutic performance of dorzagliatin. Likewise, evidence needs to be generated from other countries, patients with organ dysfunction, a history of severe hypoglycemia, cardiac diseases, and elderly patients before extending the use of dorzagliatin. Apart from monitoring lipid profiles, long-term safety studies of dorzagliatin should involve the assessment of serum uric acid, lactate, renal function, liver function, and cardiovascular parameters.

Population Pharmacokinetic/Pharmacodynamic Analysis of the Glucokinase Activator PB201 in Healthy Volunteers and Patients with Type 2 Diabetes Mellitus: Facilitating the Clinical Development of PB201 in China

PB201 is an orally active, partial glucokinase activator targeting both pancreatic and hepatic glucokinase. As the second glucokinase activator studied beyond phase I, PB201 has demonstrated promising glycemic effects as well as favorable pharmacokinetic (PK) and safety profiles in patients with type 2 diabetes mellitus (T2DM). This study aims to develop a population PK/pharmacodynamic (PD) model for PB201 using the pooled data from nine phase I/II clinical trials conducted in non-Chinese healthy volunteers and a T2DM population and to predict the PK/PD profile of PB201 in a Chinese T2DM population. We developed the PK/PD model using the non-linear mixed-effects modeling approach. All runs were performed using the first-order conditional estimation method with interaction. The pharmacokinetics of PB201 were well fitted by a one-compartment model with saturable absorption and linear elimination. The PD effects of PB201 on reducing the fasting plasma glucose and glycosylated hemoglobin levels in the T2DM population were described by indirect response models as stimulating the elimination of fasting plasma glucose, where the production of glycosylated hemoglobin was assumed to be stimulated by fasting plasma glucose. Covariate analyses revealed enhanced absorption of PB201 by food and decreased systemic clearance with ketoconazole co-administration, while no significant covariate was identified for the pharmacodynamics. The population PK model established for non-Chinese populations was shown to be applicable to the Chinese T2DM population as verified by the PK data from the Chinese phase I study. The final population PK/PD model predicted persistent and dose-dependent reductions in fasting plasma glucose and glycosylated hemoglobin levels in the Chinese T2DM population receiving 50/50 mg, 100/50 mg, and 100/100 mg PB201 twice daily for 24 weeks independent of co-administration of metformin. Overall, the proposed population PK/PD model quantitatively characterized the PK/PD properties of PB201 and the impact of covariates on its target populations, which allows the leveraging of extensive data in non-Chinese populations with the limited data in the Chinese T2DM population to successfully supported the waiver of the clinical phase II trial and facilitate the optimal dose regimen design of a pivotal phase III study of PB201 in China.

Current Insight on the Role of Glucokinase and Glucokinase Regulatory Protein in Diabetes

The glucokinase regulator (GCKR) gene encodes an inhibitor of the glucokinase enzyme (GCK), found only in hepatocytes and responsible for glucose metabolism. A common GCKR coding variation has been linked to various metabolic traits in genome-wide association studies. Rare GCKR polymorphisms influence GKRP activity, expression, and localization. Despite not being the cause, these variations are linked to hypertriglyceridemia. Because of their crystal structures, we now better understand the molecular interactions between GKRP and the GCK. Finally, small molecules that specifically bind to GKRP and decrease blood sugar levels in diabetic models have been identified. GCKR allelic spectrum changes affect lipid and glucose homeostasis. GKRP dysfunction has been linked to a variety of molecular causes, according to functional analysis. Numerous studies have shown that GKRP dysfunction is not the only cause of hypertriglyceridemia, implying that type 2 diabetes could be treated by activating liver-specific GCK via small molecule GKRP inhibition. The review emphasizes current discoveries concerning the characteristic roles of glucokinase and GKRP in hepatic glucose metabolism and diabetes. This information has influenced the growth of directed molecular therapies for diabetes, which has improved our understanding of lipid and glucose physiology.

Phenotypic Characterization of Congenital Hyperinsulinism Due to Novel Activating Glucokinase Mutations

The importance of glucokinase (GK) in the regulation of insulin secretion has been highlighted by the phenotypes of individuals with activating and inactivating mutations in the glucokinase gene (GCK). Here we report 10 individuals with congenital hyperinsulinism (HI) caused by eight unique activating mutations of GCK. Six are novel and located near previously identified activating mutations sites. The first recognized episode of hypoglycemia in these patients occurred between birth and 24 years, and the severity of the phenotype was also variable. Mutant enzymes were expressed and purified for enzyme kinetics in vitro. Mutant enzymes had low glucose half-saturation concentration values and an increased enzyme activity index compared with wild-type GK. We performed functional evaluation of islets from the pancreata of three children with GCK-HI who required pancreatectomy. Basal insulin secretion in perifused GCK-HI islets was normal, and the response to glyburide was preserved. However, the threshold for glucose-stimulated insulin secretion in perifused glucokinase hyperinsulinism (GCK-HI) islets was decreased, and glucagon secretion was greatly suppressed. Our evaluation of novel GCK disease-associated mutations revealed that the detrimental effects of these mutations on glucose homeostasis can be attributed not only to a lowering of the glucose threshold of insulin secretion but also to a decreased counterregulatory glucagon secretory response.

ARTICLE HIGHLIGHTS

Our evaluation of six novel and two previously published activating GCK mutations revealed that the detrimental effects of these mutations on glucose homeostasis can be attributed not only to a lowering of the glucose threshold of insulin secretion but also to a decreased counterregulatory glucagon secretory response. These studies provide insights into the pathophysiology of GCK-hyperinsulinism and the dual role of glucokinase in β-cells and α-cells to regulate glucose homeostasis.

A multicentre, randomized, double-blind, parallel, active- and placebo-controlled Phase 3 clinical study of the glucokinase activator PB-201 in treatment-naive patients with type 2 diabetes mellitus: A study protocol

AIM

To report the rationale for using PB-201, a partial glucokinase activator (GKA), for a Phase 3 study (NCT05102149) assessing its efficacy and safety in a Chinese population and to describe the design of this GKA Phase 3 trial, the first to involve both an active control and a placebo control arm.

MATERIALS AND METHODS

This is an ongoing, multicentre, randomized, double-blind, three-arm placebo and active control study to be carried out among 672 Chinese treatment-naive participants with type 2 diabetes mellitus (T2DM) to assess the efficacy and safety of PB-201 for approximately 60 weeks, including a screening period and a safety follow-up period.

RESULTS

The primary objective of this study was to monitor change in glycated haemoglobin levels with PB-201 in treatment-naive T2DM participants from baseline to 24 weeks in comparison with vildagliptin and placebo. The key secondary objective was to assess the efficacy and safety of PB-201 following treatment for a time period of 52 weeks.

CONCLUSION

This pivotal study will offer critical information regarding the efficacy and safety of PB-201 in Chinese treatment-naive T2DM participants that would help to establish robust evidence for the benefit-risk evaluation of this drug.

Efficacy and safety of novel dual glucokinase activator dorzagliatin in type-2 diabetes A meta-analysis

BACKGROUND & AIMS

Glucokinase has a critical role in regulating glucose homeostasis in humans, and has been a target for diabetes drug development since 1990s. Dorzagliatin is a novel allosteric dual glucokinase activator targeting both pancreatic and hepatic glucokinase. No meta-analysis has analysed the efficacy and safety of dorzagliatin in type-2 diabetes (T2DM). We undertook this meta-analysis to address this knowledge-gap.

METHODS

Electronic databases were searched for RCTs involving T2DM patients receiving dorzagliatin in intervention arm, and placebo/active comparator in control arm. Primary outcome was to evaluate changes in HbA1c. Secondary outcomes were to evaluate alterations in blood glucose parameters, lipids, insulin-resistance and adverse events.

RESULTS

From initially screened 17 articles, data from 3 RCTs (1333 patients) was analysed. Over 12-24 weeks use, dorzagliatin had significantly higher lowering of HbA1c [MD -0.66% (95%CI: -0.74 to -0.59); P < 0.01; I² = 99%], fasting glucose [MD -32.03 mg/dl (95%CI: 45.12 to -18.94); P < 0.01; I² = 100%], 2-h post-prandial glucose [MD -43.49 mg/dl (95%CI: -46.26 to -40.72); P < 0.01; I² = 90%] along with greater number of patients achieving HbA1c<7% [OR 6.01 (95% CI: 2.50-14.46); P < 0.01; I² = 83%], as compared to placebo. Dorzagliatin was associated with significant elevation of triglycerides [MD 0.43 mmol/L (95%CI:0.30-0.56); P < 0.01; I² = 0%], greater occurrence of hyperlipidaemia [RR 1.52 (95% CI:1.05-2.18); P = 0.03; I² = 0%], and increase in body-weight [MD 0.40 kg (95%CI:0.06-0.75); P = 0.03; I² = 0%], compared to placebo. The occurrence of total-adverse-events [RR 1.43 (95%CI:1.11-1.83); P < 0.01; I² = 0%] but not severe adverse-events [RR 0.92 (95%CI:0.54-1.57); P = 0.76; I² = 0%] was significantly higher with dorzagliatin.

CONCLUSION

Dorzagliatin has good glycaemic efficacy and well tolerated over 6-months use. Mild increase in body-weight, serum triglycerides and overall adverse events remain issues of concern warranting further evaluation in longer clinical trials with active controls.

Novel Approaches to the Management of Diabetes Mellitus in Patients with Coronary Artery Disease

Cardiovascular disease (CVD) is the leading cause of morbidity and mortality in individuals with diabetes mellitus (DM). Although benefit has been attributed to the strict control of hyperglycemia with traditional antidiabetic treatments, novel antidiabetic medications have demonstrated cardiovascular (CV) safety and benefits by reducing major adverse cardiac events, improving heart failure (HF), and decreasing CVD-related mortality. Emerging data underline the interrelation between diabetes, as a metabolic disorder, and inflammation, endothelial dysfunction, and oxidative stress in the pathogenesis of microvascular and macrovascular complications. Conventional glucose-lowering medications demonstrate controversial CV effects. Dipeptidyl peptidase- 4 inhibitors have not only failed to prove to be beneficial in patients with coronary artery disease, but also their safety is questionable for the treatment of patients with CVD. However, metformin, as the first-line option for type 2 DM (T2DM), shows CVD protective properties for DM-induced atherosclerotic and macrovascular complications. Thiazolidinedione and sulfonylureas have questionable effects, as evidence from large studies shows a reduction in the risk of CV events and deaths, but with an increased rate of hospitalization for HF. Moreover, several studies have revealed that insulin monotherapy for T2DM treatment increases the risk of major CV events and deaths from HF, when compared to metformin, although it may reduce the risk of myocardial infarction. Finally, this review aimed to summarize the mechanisms of action of novel antidiabetic drugs acting as glucagon-like peptide-1 receptor agonists and sodium-glucose co-transporter-2 inhibitors that show favorable effects on blood pressure, lipid levels, and inflammation, leading to reduced CVD risk in T2DM patients.

Efficacy and safety of dorzagliatin for type 2 diabetes mellitus: A meta-analysis and trial sequential analysis

Objective

To evaluate the efficacy and safety of dorzagliatin in the treatment of type 2 diabetes mellitus (T2DM) by using meta-analysis and trial sequential analysis (TSA).

Method

Search for clinical trials of dorzagliatin for T2DM in eight databases, with a time limit of build to July 2022. The included studies that met the requirements were carried out for meta-analysis and TSA.

Results

In terms of efficacy endpoints, meta-analysis showed that dorzagliatin decreased glycated hemoglobin A1c(HbA1c) [mean difference (MD) -0.65%, 95% confidence interval (CI) -0.76 ~ -0.54, P < 0.00001], fasting plasma glucose (FPG) (MD -9.22 mg/dL, 95% CI -9.99 ~ -8.44, P < 0.00001), 2 h postprandial glucose (2h-PPG) (MD -48.70 mg/dL, 95% CI -55.45 ~ -41.96, P < 0.00001), homeostasis model assessment 2 of insulin resistance (HOMA2-IR) (MD -0.07, 95% CI -0.14 ~ -0.01, P = 0.03) and increased homeostasis model assessment 2 of ß-cells function (HOMA2-β) (MD 2.69, 95% CI 1.06 ~ 4.31, P = 0.001) compared with placebo. And TSA revealed that the benefits observed for the current information set were conclusive, except for HOMA2-IR. In comparison with placebo, dorzagliatin increased triglyceride(TG) (MD 0.43 mmol/L, 95% CI 0.30 ~ 0.56, P < 0.00001), total cholesterol (TC) (MD 0.13 mmol/L, 95% CI 0.05 ~ 0.21, P = 0.001), body weight (MD 0.38 kg, 95% CI 0.12-0.63, P = 0.004) and body mass index (BMI) (MD 0.14 kg/m², 95% CI 0.05-0.24, P = 0.003), while low density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), systolic blood pressure (SBP) and diastolic blood pressure (DBP) were comparable. And TSA demonstrated that TG, TC, body weight, and BMI were conclusive. In terms of safety endpoints, dorzagliatin increased total adverse events (AEs) [risk ratio (RR) 1.56, 95% CI 1.06 ~ 2.30, P = 0.03], while serious AEs, hyperlipidemia, and hypoglycaemia were all comparable. And TSA indicated that the results need to be confirmed by additional studies. Harbord regression showed no publication bias.

Conclusion

Dorzagliatin was effective in lowering glycemia, reducing insulin resistance and improving islet ß-cells function without affecting blood pressure, LDL-C, and HDL-C. Although dorzagliatin caused a mild increase in TG and TC, it did not increase the incidence of hyperlipidemia, and the small increases in body weight and BMI were not clinically significant enough. In terms of safety, the total AEs caused by dorzagliatin may be a cumulative effect of single AEs, with no drug-related adverse event being reported at a higher incidence than placebo alone. Dorzagliatin's serious AEs, hyperlipidemia, and hypoglycemia are comparable to that of placebo, and dorzagliatin has a good safety profile.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=371802 identifier: CRD42022371802.

Dorzagliatin in drug-naïve patients with type 2 diabetes: a randomized, double-blind, placebo-controlled phase 3 trial

Improving glucose sensitivity remains an unmet medical need in treating type 2 diabetes (T2D). Dorzagliatin is a dual-acting, orally bioavailable glucokinase activator that enhances glucokinase activity in a glucose-dependent manner, improves glucose-stimulated insulin secretion and demonstrates effects on glycemic control in patients with T2D. We report the findings of a randomized, double-blind, placebo-controlled phase 3 clinical trial to evaluate the efficacy and safety of dorzagliatin in patients with T2D. Eligible drug-naïve patients with T2D (n = 463) were randomly assigned to the dorzagliatin or placebo group at a ratio of 2:1 for 24 weeks of double-blind treatment, followed by 28 weeks of open-label treatment with dorzagliatin for all patients. The primary efficacy endpoint was the change in glycated hemoglobin from baseline to week 24. Safety was assessed throughout the trial. At week 24, the least-squares mean change in glycated hemoglobin from baseline (95% confidence interval) was -1.07% (-1.19%, -0.95%) in the dorzagliatin group and -0.50% (-0.68%, -0.32%) in the placebo group (estimated treatment difference, -0.57%; 95% confidence interval: -0.79%, -0.36%; P < 0.001). The incidence of adverse events was similar between the two groups. There were no severe hypoglycemia events or drug-related serious adverse events in the dorzagliatin group. In summary, dorzagliatin improved glycemic control in drug-naïve patients with T2D and showed a good tolerability and safety profile.

Dorzagliatin add-on therapy to metformin in patients with type 2 diabetes: a randomized, double-blind, placebo-controlled phase 3 trial

Metformin, the first-line therapy for type 2 diabetes (T2D), decreases hepatic glucose production and reduces fasting plasma glucose levels. Dorzagliatin, a dual-acting orally bioavailable glucokinase activator targeting both the pancreas and liver glucokinase, decreases postprandial glucose in patients with T2D. In this randomized, double-blind, placebo-controlled phase 3 trial, the efficacy and safety of dorzagliatin as an add-on therapy to metformin were assessed in patients with T2D who had inadequate glycemic control using metformin alone. Eligible patients with T2D (n = 767) were randomly assigned to receive dorzagliatin or placebo (1:1 ratio) as an add-on to metformin (1,500 mg per day) for 24 weeks of double-blind treatment, followed by 28 weeks of open-label treatment with dorzagliatin for all patients. The primary efficacy endpoint was the change in glycated hemoglobin (HbA1c) levels from baseline to week 24, and safety was assessed throughout the trial. At week 24, the least-squares mean change from baseline in HbA1c (95% confidence interval (CI)) was -1.02% (-1.11, -0.93) in the dorzagliatin group and -0.36% (-0.45, -0.26) in the placebo group (estimated treatment difference, -0.66%; 95% CI: -0.79, -0.53; P < 0.0001). The incidence of adverse events was similar between groups. There were no severe hypoglycemia events or drug-related serious adverse events in the dorzagliatin and metformin combined therapy group. In patients with T2D who experienced inadequate glycemic control with metformin alone, dorzagliatin resulted in effective glycemic control with good tolerability and safety profile ( NCT03141073 ).

Glucokinase activation leads to an unsustained hypoglycaemic effect with hepatic triglyceride accumulation in db/db mice

AIM

To investigate how subchronic administration of a glucokinase activator (GKA) results in attenuation of the hypoglycaemic effect in the diabetic condition.

MATERIALS AND METHODS

Six-week-old db/db mice were fed standard chow containing a GKA or the sodium-glucose cotransporter 2 inhibitor ipragliflozin for 1, 6, 14 or 28 days. We performed histological evaluation and gene expression analysis of the pancreatic islets and liver after each treatment and compared the results to those in untreated mice.

RESULTS

The unsustained hypoglycaemic effect of GKAs was reproduced in db/db mice in conjunction with significant hepatic fat accumulation. The initial reactions to treatment with the GKA in the liver were upregulation of the gene expression of carbohydrate response element-binding protein beta (Chrebp-b) and downregulation of phosphoenolpyruvate carboxykinase (Pepck) on day 1. Subsequently, the initial changes in Chrebp-b and Pepck disappeared and increases in the expression of genes involved in lipogenesis, including acetyl-CoA carboxylase and fatty acid synthase, were observed. There were no significant changes in the pancreatic β cells nor in hepatic insulin signalling.

CONCLUSIONS

The GKA showed an unsustained hypoglycaemic effect and promoted hepatic fat accumulation in db/db mice. Dynamic changes in the expression of hepatic genes involved in lipogenesis and gluconeogenesis could affect the unsustained hypoglycaemic effect of the GKA despite no changes in pancreatic β-cell function and mass.

One hundred years since insulin discovery: An update on current and future perspectives for pharmacotherapy of diabetes mellitus

Diabetes mellitus was considered a fatal malady until the discovery, extraction and commercial availability of insulins. Numerous other classes of drugs ranging from sulfonylureas to sodium-glucose co-transporter-2 inhibitors were then marketed. However, with the prevalence of diabetes mellitus increasing every year, many more drugs and therapies are under investigation. This review article aimed to summarize the significant developments in the pharmacotherapy of diabetes mellitus and outline the progress made by the recent advances, 100 years since insulins were first extracted successfully. Insulin analogues and insulin delivery pumps have further improved glycaemic control in diabetes mellitus. Cardiovascular and renal outcome trials have changed the landscape of diabetology, with some of these drugs also efficacious in nondiabetics. Newer drug delivery systems are being evaluated to improve the efficacy and reduce the dosing frequency and adverse effects of antidiabetics. Some newer drugs with novel mechanisms of action targeting type 1 and type 2 diabetes have also shown promise in recent clinical trials. These drugs include dual glucose-dependent insulinotropic polypeptide and glucagon-like peptide 1-agonists, glucokinase activators, anti-CD3 monoclonal antibodies and glimins. Their efficacy needs to be evaluated in larger studies.

Antidiabetic Potential of Volatile Cinnamon Oil: A Review and Exploration of Mechanisms Using In Silico Molecular Docking Simulations

Cinnamon has been used as a flavoring and medicinal agent for centuries. Much research has focused on cinnamon bark powder, which contains antioxidants, flavonoids, carotenoids, vitamins, minerals, fiber, and small amounts of essential oil. However, isolated and concentrated cinnamon essential oil may also have important medicinal qualities, particularly in antidiabetic therapy. Some of the most common essential oil constituents identified in the literature include cinnamaldehyde, eugenol, and beta-caryophyllene. Due to their high concentration in cinnamon essential oil, these constituents are hypothesized to have the most significant physiological activity. Here, we present a brief review of literature on cinnamon oil and its constituents as they relate to glucose metabolism and diabetic pathogenesis. We also present molecular docking simulations of these cinnamon essential oil constituents (cinnamaldehyde, eugenol, beta-caryophyllene) that suggest interaction with several key enzymes in glucometabolic pathways.

Glucokinase as an emerging anti-diabetes target and recent progress in the development of its agonists

Type 2 diabetes mellitus is a metabolic disorder with complicated pathogenesis, and mono-target therapy often fails to effectively manage the levels of blood glucose. In recent years, the anti-diabetes target glucokinase (GK) has attracted the attention of researchers. It acts as a glucose sensor, triggering counter regulatory responses following a change in glucose levels to aid restoration of normoglycemia. Activation of GK induces glucose metabolism and reduces glucose levels for the treatment of type 2 diabetes. GK agonists (GKA) are a new class of antidiabetic drugs. Among these agents, dorzagliatin is currently being investigated in phase III clinical trials, while PB-201 and AZD-1656 have reached phase II clinical trials. This article describes the mechanism of action of GK in diabetes and of action of GKA at the protein level, and provides a review of the research, trends, and prospects regarding the use of GKA in this setting.

A comprehensive review on glucokinase activators: Promising agents for the treatment of Type 2 diabetes

Glucokinase is a key enzyme which converts glucose into glucose-6-phosphate in the liver and pancreatic cells of the human. In the liver, glucokinase promotes the synthesis of glycogen, and in the pancreas, it helps in glucose-sensitive insulin release. It serves as a "glucose sensor" and thereby plays an important role in the regulation of glucose homeostasis. Due to this activity, glucokinase is considered as an attractive drug target for type 2 diabetes. It created a lot of interest among the researchers, and several small molecules were discovered. The research work was initiated in 1990. However, the hypoglycemic effect, increased liver burden, and loss of efficacy over time were faced during clinical development. Dorzagliatin, a novel glucokinase activator that acts on both the liver and pancreas, is in the late-stage clinical development. TTP399, a promising hepatoselective GK activator, showed a clinically significant and sustained reduction in glycated hemoglobin with a low risk of adverse effects. The successful findings generated immense interest to continue further research in finding small molecule GK activators for the treatment of type 2 diabetes. The article covers different series of GK activators reported over the past decade and the structural insights into the GK-GK activator binding which, we believe will stimulate the discovery of novel GK activators to treat type 2 diabetes.

The efficacy and safety of glucokinase activators for the treatment of type-2 diabetes mellitus: A meta-analysis

BACKGROUND

Glucokinase activators (GKAs) are a novel family of glucose-lowering agents used for the treatment of type-2 diabetes mellitus. Treatment with different GKAs has been shown to reduce blood glucose levels in these patients. We compared the efficacy/safety of GKAs in patients with type-2 diabetes mellitus through a meta-analysis.

METHODS

We searched the PubMed, Excerpt Medica Database, and Cochrane Central Register of Controlled Trials databases for articles published before December 30, 2020. We computed the weighted mean difference (WMD) and 95% confidence interval (CI) for the change from baseline to the study endpoint for GKA versus placebo treatments.

RESULTS

A total of 4 articles (5 studies) were included in the meta-analysis. GKAs were associated with reductions in glycated hemoglobin levels from baseline (WMD, -0.3%; 95% CI, -0.466% to -0.134%). No significant difference between GKA and placebo treatment was observed in the results of fasting plasma glucose levels from baseline (WMD 0.013 mmol/L; 95% CI, -0.304-0.33 mmol/L). A significantly higher change in 2-hour postprandial plasma glucose (2-h PPG) levels (WMD -2.434 mmol/L; 95% CI, -3.304 to -1.564 mmol/L) was observed following GKA than placebo treatment. GKAs were associated with a higher prevalence of causing hypoglycemic events than placebo treatment (risk difference [RD], 0.06; 95% CI 0.013-0.106). GKAs had no association with the risk of developing adverse effects (RD, 0.038; 95% CI, -0.03-0.106) and serious adverse events (RD, 0.01; 95% CI, -0.004-0.023).

CONCLUSIONS

GKAs were more effective for postprandial blood glucose control. However, these agents showed a significantly high risk of causing hypoglycemia.

PROSPERO REGISTRATION NUMBER

CRD42021220364.

Novel therapies with precision mechanisms for type 2 diabetes mellitus

Type 2 diabetes mellitus (T2DM) is one of the greatest health crises of our time and its prevalence is projected to increase by >50% globally by 2045. Currently, 10 classes of drugs are approved by the US Food and Drug Administration for the treatment of T2DM. Drugs in development for T2DM must show meaningful reductions in glycaemic parameters as well as cardiovascular safety. Results from an increasing number of cardiovascular outcome trials using modern T2DM therapeutics have shown a reduced risk of atherosclerotic cardiovascular disease, congestive heart failure and chronic kidney disease. Hence, guidelines have become increasingly evidence based and more patient centred, focusing on reaching individualized glycaemic goals while optimizing safety, non-glycaemic benefits and the prevention of complications. The bar has been raised for novel therapies under development for T2DM as they are now expected to achieve these aims and possibly even treat concurrent comorbidities. Indeed, the pharmaceutical pipeline for T2DM is fertile. Drugs that augment insulin sensitivity, stimulate insulin secretion or the incretin axis, or suppress hepatic glucose production are active in more than 7,000 global trials using new mechanisms of action. Our collective goal of being able to truly personalize medicine for T2DM has never been closer at hand.

Pyridoxine dipharmacophore derivatives as potent glucokinase activators for the treatment of type 2 diabetes mellitus

Glucokinase is one of the promising targets for glucose-lowering agents, and the development of GK activators are now considered as one of the most promising strategies for the treatment of type 2 diabetes mellitus. In this work, a series of novel symmetric molecular constructs, in which two pyridoxine moieties are connected via sulfur-containing linkers, have been synthesized and tested in vitro for glucokinase activation potential. The enzyme activation rates by two most active compounds at 100 μM (~150% and 130%) were comparable to that of the reference agent PF-04937319 (~154%). Both leading compounds demonstrated low cytotoxicity and excellent safety profile in acute toxicity experiment in rats after oral administration with LD₅₀ exceeding 2000 mg/kg of body weight. Binding mode of the active compounds in comparison with the reference agent was studied using molecular docking. The leading compounds represent viable preclinical candidates for the treatment of type 2 diabetes mellitus, as well as a promising starting point for the design of structural analogs with improved activity.

Identification of mangiferin as a potential Glucokinase activator by structure-based virtual ligand screening

The natural product mangiferin (compound 7) has been identified as a potential glucokinase activator by structure-based virtual ligand screening. It was proved by enzyme activation experiment and cell-based assays in vitro, with potency in micromolar range. Meanwhile, this compound showed good antihyperglycemic activity in db/db mice without obvious side effects such as excessive hypoglycaemia.

Targeting hepatic glucose metabolism in the treatment of type 2 diabetes

Type 2 diabetes mellitus is characterized by the dysregulation of glucose homeostasis, resulting in hyperglycaemia. Although current diabetes treatments have exhibited some success in lowering blood glucose levels, their effect is not always sustained and their use may be associated with undesirable side effects, such as hypoglycaemia. Novel antidiabetic drugs, which may be used in combination with existing therapies, are therefore needed. The potential of specifically targeting the liver to normalize blood glucose levels has not been fully exploited. Here, we review the molecular mechanisms controlling hepatic gluconeogenesis and glycogen storage, and assess the prospect of therapeutically targeting associated pathways to treat type 2 diabetes.

Pharmacokinetic and Pharmacodynamic Drug Interaction Study of Piragliatin, a Glucokinase Activator, and Glyburide, a Sulfonylurea, in Type 2 Diabetic Patients

A glucokinase activator and a sulfonylurea might be coprescribed to synergize treatment success for type 2 diabetes (T2D). This clinical pharmacology study was designed to investigate the potential glucose-lowering effect or pharmacodynamic (PD), pharmacokinetic (PK), and safety/tolerability interactions between piragliatin and glyburide in T2D patients already taking glyburide but not adequately controlled. This was an open-label, multiple-dose, 3-period, single-sequence crossover design: on days -1, 6, and 12, PD and PK samples were drawn with glyburide alone (period 0), piragliatin + glyburide (period 1), and piragliatin alone (period 2) treatments. The glucose-lowering effect, including fasting plasma glucose (FPG), of piragliatin was more pronounced when it was administered concomitantly with glyburide as compared to piragliatin or glyburide administered alone. However, this enhancement cannot be explained by a potential PK interaction between piragliatin and glyburide. Other than hypoglycemia, there were no clinically relevant safety findings. Thus, the enhanced PD effect warrants further investigation to define the optimal dose combination between glucokinase activators and sulfonylureas with regard to efficacy, safety, and tolerability.