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 protocol for systematic review and meta-analysis.

BACKGROUND: Glucokinase activators are a novel family of glucose-lowering agents used for the treatment of type-2 diabetes mellitus (T2DM). Glucokinase activators blind to GK activate the enzyme allosterically. Treatment with different GKAs has been shown to reduce fasting and postprandial glucose in patients with type 2 diabetes. We compared the efficacy/safety of glucokinase activators in T2DM patients through a meta-analysis. METHODS: We searched PubMed, Excerpt Medica Database, and Cochrane Central Register of Controlled Trials databases for articles published before December 30, 2020. Two independent reviewers extracted the information from article. The quality of articles were assessed by 2 independent reviewers using the 5 items of scale proposed by Jadad. We computed the weighted mean difference and 95% confidence interval (CI) for a change from baseline to the study endpoint for glucokinase activators vs placebo. Egger test and Begg test were used to assess the possible publication bias caused by the tendency of published studies to be positive. RESULTS: The present meta-analysis will compare the efficacy and safety of glucokinase activators and placebo for the treatment of T2DM. CONCLUSIONS: This meta-analysis will provide advanced evidence on the efficacy and safety of glucokinase activators for the treatment of T2DM. ETHICS AND DISSEMINATION: Ethical approval and patient consent are not required because this study is a literature-based study. This systematic review and meta-analysis will be published in a peer-reviewed journal. PROSPERO REGISTRATION NUMBER: CRD42021220364.

Recent clinical advances of glucokinase activators in the treatment of diabetes mellitus type 2.

Glucokinase (GK) is an isozyme of hexokinase that catalyzes the phosphorylation of glucose. GK is present in many organs of the human body, including the liver and pancreas. GK plays an important role in promoting the synthesis of hepatic glycogen and balancing postprandial blood glucose. Mutations in the GK gene can result in the inclusion of maturity-onset diabetes of the young (MODY2) and permanent neonatal Diabetes mellitus (PNDM). Glucokinase activators (GKAs) are a class of type 2 diabetes drugs designed for this target. In various animal models of type 2 diabetes, GKAs have been shown to have the ability to decrease blood glucose, and some GKAs also have the ability to stimulate ß cell proliferation. However, due to the induction of hypoglycemia and increased liver burden, many candidates stopped in phase II clinical trials. Recently, dorzagliatin has reached the primary endpoint of phase III clinical trial, which can repair the core function of GK as a blood glucose sensor, and can delay or even reverse islet ß -cell damage and functional decline. This provides a promising prospect for the study of GKAs as candidates for the treatment of type 2 diabetes. This review summarizes the clinical advances in GKAs.

TTP399: an investigational liver-selective glucokinase (GK) activator as a potential treatment for type 2 diabetes.

Introduction: Type 2 diabetes is a complex metabolic disorder defined by hyperglycemia which occurs because of impaired insulin secretion and sensitivity. There is an ongoing need to develop novel therapies that are effective and safe with minimal side effects and long-term durability. TTP399 is a hepatoselective, glucokinase activator with potential for treating type 2 diabetes. Areas covered: This is a review of the available data regarding the mechanism of action and the pharmacokinetics of TTP399. The efficacy and safety of the drug for treatment of type 2 diabetes will also be examined with an emphasis on the results of a randomized, controlled phase 2 study. Expert opinion: TTP399 could offer significant advantages over currently available therapies for type 2 diabetes. It successfully lowers glucose without side effects such as hypoglycemia, weight gain or dyslipidemia. Larger trials are required to understand long-term efficacy and safety of this medication in various patient populations and to elucidate its effect on the pathologic processes underpinning type 2 diabetes.

Correcting Postprandial Hyperglycemia in Zucker Diabetic Fatty Rats With an SGLT2 Inhibitor Restores Glucose Effectiveness in the Liver and Reduces Insulin Resistance in Skeletal Muscle.

Ten-week-old Zucker diabetic fatty (ZDF) rats at an early stage of diabetes embody metabolic characteristics of obese human patients with type 2 diabetes, such as severe insulin and glucose intolerance in muscle and the liver, excessive postprandial excursion of plasma glucose and insulin, and a loss of metabolic flexibility with decreased lipid oxidation. Metabolic flexibility and glucose flux were examined in ZDF rats during fasting and near-normal postprandial insulinemia and glycemia after correcting excessive postprandial hyperglycemia using treatment with a sodium-glucose cotransporter 2 inhibitor (SGLT2-I) for 7 days. Preprandial lipid oxidation was normalized, and with fasting, endogenous glucose production (EGP) increased by 30% and endogenous glucose disposal (E-Rd) decreased by 40%. During a postprandial hyperglycemic-hyperinsulinemic clamp after SGLT2-I treatment, E-Rd increased by normalizing glucose effectiveness to suppress EGP and stimulate hepatic glucose uptake; activation of glucokinase was restored and insulin action was improved, stimulating muscle glucose uptake in association with decreased intracellular triglyceride content. In conclusion, SGLT2-I treatment improves impaired glucose effectiveness in the liver and insulin sensitivity in muscle by eliminating glucotoxicity, which reinstates metabolic flexibility with restored preprandial lipid oxidation and postprandial glucose flux in ZDF rats.

Priming Effect of a Morning Meal on Hepatic Glucose Disposition Later in the Day.

We used hepatic balance and tracer ([3H]glucose) techniques to examine the impact of "breakfast" on hepatic glucose metabolism later in the same day. From 0-240 min, 2 groups of conscious dogs (n = 9 dogs/group) received a duodenal infusion of glucose (GLC) or saline (SAL), then were fasted from 240-360 min. Three dogs from each group were euthanized and tissue collected at 360 min. From 360-600 min, the remaining dogs underwent a hyperinsulinemic (4× basal) hyperglycemic clamp (arterial blood glucose 146 ± 2 mg/dL) with portal GLC infusion. The total GLC infusion rate was 14% greater in dogs infused with GLC than in those receiving SAL (AUC360-600min 2,979 ± 296 vs. 2,597 ± 277 mg/kg, respectively). The rates of hepatic glucose uptake (5.8 ± 0.8 vs. 3.2 ± 0.3 mg ⋅ kg-1 ⋅ min-1) and glycogen storage (4.7 ± 0.6 vs. 2.9 ± 0.3 mg ⋅ kg-1 ⋅ min-1) during the clamp were markedly greater in dogs receiving GLC compared with those receiving SAL. Hepatic glycogen content was ∼50% greater, glycogen synthase activity was ∼50% greater, glycogen phosphorylase activity was ∼50% lower, and the amount of phosphorylated glycogen synthase was 34% lower, indicating activation of the enzyme, in dogs receiving GLC compared with those receiving SAL. Thus, morning GLC primed the liver to extract and store more glucose in the presence of hyperinsulinemic hyperglycemia later in the same day, indicating that breakfast enhances the liver's role in glucose disposal in subsequent same-day meals.

Translational Modeling and Simulation in Supporting Early-Phase Clinical Development of New Drug: A Learn-Research-Confirm Process.

BACKGROUND AND OBJECTIVE: Pharmacokinetic/pharmacodynamic modeling and simulation can aid clinical drug development by dynamically integrating key system- and drug-specific information into predictive profiles. In this study, we propose a methodology to predict pharmacokinetic/pharmacodynamic profiles of sinogliatin (HMS-5552, RO-5305552), a novel glucokinase activator to treat diabetes mellitus, for first-in-patient (FIP) studies. METHODS AND RESULTS: Initially, pharmacokinetic/pharmacodynamic profiles of sinogliatin and another glucokinase activator (US2) previously acquired from healthy subjects were fitted using Model A incorporating an indirect response mechanism. The pharmacokinetic/pharmacodynamic profiles of US2 in patients with type 2 diabetes mellitus (T2DM) were then fitted using Model B incorporating circadian rhythm and food effects after thoughtful research on the difference between healthy subjects and T2DM patients. The differences in results between the two US2 modeling populations were used to scale the values of the pharmacodynamic parameters and refine the pharmacodynamic model of sinogliatin, which was then utilized to project pharmacokinetic/pharmacodynamic profiles of sinogliatin in T2DM patients after an 8-day simulated treatment. Results showed that the projected pharmacokinetic/pharmacodynamic values of five parameters were within 70-130% of values fitted from observed clinical data while the other two remaining projected parameters were within a twofold error. Population pharmacokinetic/pharmacodynamic analysis conducted for sinogliatin also suggested that age and sex were significantly correlated to pharmacokinetic/pharmacodynamic characteristics. Additionally, Model B was combined with a glycosylated hemoglobin (HbA1c) compartment to form Model C, which was then used to project serum HbA1c levels in patients after a 1-month simulated treatment of sinogliatin. The predicted HbA1c changes were nearly identical to observed clinical values (0.82 vs. 0.78%). CONCLUSIONS: Model-based drug development methods utilizing a learn-research-confirm cycle may accurately project pharmacokinetic/pharmacodynamic profiles of new drugs in FIP studies.

Glycemic Effect and Safety of a Systemic, Partial Glucokinase Activator, PF-04937319, in Patients With Type 2 Diabetes Mellitus Inadequately Controlled on Metformin-A Randomized, Crossover, Active-Controlled Study.

Glucokinase enhances glucose conversion to glucose-6-phosphate, causing glucose-stimulated insulin secretion from pancreatic ß cells and increased hepatic glucose uptake. PF-04937319 is a partial glucokinase activator designed to maintain efficacy with reduced hypoglycemia risk. In this randomized, double-blind, double-dummy, 3-period crossover phase 1b study, patients aged 18-70 years with type 2 diabetes mellitus and on metformin received once-daily PF-04937319 (300 mg), split-dose PF-04937319 (150+100 mg; breakfast+lunch), or sitagliptin (100 mg once daily). The primary end point was day 14 weighted mean daily glucose (WMDG) change from period-specific baseline. Secondary end points included change from baseline in fasting plasma glucose, premeal C-peptide and insulin, and safety, including hypoglycemia frequency. Mean decrease from baseline in observed WMDG (mg/dL) was greater for PF-04937319 (split-dose, -31.24; once daily, -31.33) versus sitagliptin (-19.24). Using the integrated glucose red-cell HbA1c model, the observed WMDG effect with both PF-04937319 dosing regimens was projected to yield a clinically superior effect on mean glycated hemoglobin (HbA1c ; split-dose, -0.88%; once daily, -0.94%) compared with sitagliptin (-0.63%). There was no difference in premeal C-peptide or insulin levels, and although the effect on WMDG with both PF-04937319 regimens was similar, the split-dose regimen appeared to offer some advantage in safety and tolerability.

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.

Control of liver glucokinase activity: A potential new target for incretin hormones?

We tested the exendin-4 and des-fluoro-sitagliptin effects on fructose-induced increase in liver glucokinase activity in rats with impaired glucose tolerance and the exendin-4 effect on glucokinase activity in HepG2 cells incubated with fructose in the presence/absence of exendin-9-39. After 3 weeks of in vivo fructose administration we measured: (1) serum glucose, insulin and triglyceride levels; (2) liver and HepG2 cells glucokinase activity and (3) liver glucokinase and 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase mRNA and protein levels. Fructose fed rats had: hypertriglyceridemia, hyperinsulinemia and high liver glucokinase activity (mainly located in the cytosolic fraction) together with higher glucokinase and 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase mRNA and protein concentrations compared to control rats. Co-administration of either exendin-4 or des-fluoro-sitagliptin prevented serum and liver changes except glucokinase protein expression. Exendin-4 also prevented fructose-induced increase in glucokinase activity in cultured HepG2 cells, effect blunted by co-incubation with exendin-9-36. In conclusion exendin-4/des-fluro-sitagliptin prevented fructose-induced effect on glucokinase activity, mainly affecting enzyme activity modulators. Exendin 9-39 blunted in vitro protective exendin-4 effect on glucokinase activity, thus suggesting a direct effect of the later on hepatocytes through GLP-1 receptor. Alterations of glucokinase activity modulators could play a role in the pathogenesis of liver dysfunction, becoming a potential new treatment target for GLP-1 receptor agonists.

[New therapies for type 2 diabetes mellitus]. / Nuevos agentes terapéuticos para la diabetes tipo 2.

The increasing prevalence of obesity and type 2 diabetes mellitus (T2DM) has led to a growing interest in the investigation of new therapies. Treatment of T2DM has focused on the insulinopenia and insulin resistance. However, in the last 10 years, new lines of research have emerged for the treatment of T2DM and preclinical studies appear promising. The possibility of using these drugs in combination with other currently available drugs will enhance the antidiabetic effect and promote weight loss with fewer side effects. The data provided by post-marketing monitoring will help us to better understand their safety profile and potential long-term effects on target organs, especially the cardiovascular risk.

Molecular mechanisms of anti-hyperglycemic effects of Costus speciosus extract in streptozotocin-induced diabetic rats.

OBJECTIVES: To investigate the mechanisms of the anti-hyperglycemic effect of Costus speciosus (C. speciosus) root ethanolic extracts (CSREt) by assessing its action on insulin synthesis and glucose catabolic enzyme gene expression and activities in streptozotocin (STZ) diabetic rats. METHODS: This study was carried out at the Biochemical Laboratory, Faculty of Veterinary Medicine, Zagazig University, Zagazig, Egypt between July and August 2013. Sixty male albino rats (120 +/- 20 g weight, and 6 months old) were used and divided into 6 groups (n=10). Two groups served as diabetic and nondiabetic controls. Four groups of STZ diabetic animals were given oral C. speciosus (CSREt) in doses of 200, 400, and 600 mg/kg body weight, and 600 µg/kg body weight of the standard drug glibenclamide for 4 weeks. RESULTS: The CSREt 400 and 600 mg/kg body weight induced a decrease in blood glucose and an increase in serum insulin level, glucokinase (GK), aldolase, pyruvate kinase (PK), succinate dehydrogenase (SDH), and glycogen synthase activities  in addition to a higher expression level of insulin, insulin receptor A (IRA), GK, PK, SDH, and glucose transporting protein. CONCLUSION: The C. speciosus has anti-hyperglycemic activity. It induces insulin secretion and release from cells, as well as stimulates the tissue's insulin sensitivity leading to an increase of the tissues' glucose uptake, storage, and oxidation.

Lessons from glucokinase activators: the problem of declining efficacy.

The concept of activation of glucokinase (encoded by the Gck gene) as a potential therapy for type 2 diabetes has been explored by several pharmaceutical companies. Small-molecule Gck activators (GKAs) were found to be effective at increasing glucose disposal by hepatocytes and lowering blood glucose in animal models of diabetes during acute or chronic exposure and in human type 2 diabetes during short-term exposure. However, several clinical trials of GKAs were discontinued because of declining efficacy during chronic exposure or other issues. In some cases, declining efficacy was associated with an increase in plasma triglycerides. Accordingly, increased hepatic triglyceride production or steatosis was inferred as the likely cause for declining efficacy. However, other mechanisms of tachyphylaxis need to be considered. For example, elevated glucose concentration causes induction of glucose 6-phosphatase (G6pc) and repression of Gck in hepatocytes. This is best explained as an adaptative mechanism to maintain intracellular phosphometabolite homeostasis. Enhancement of G6pc induction and Gck repression by GKAs because of perturbed phosphometabolite homeostasis could explain the decline in GKA efficacy during chronic exposure. Progress in understanding the mechanisms of intracellular phosphometabolite homeostasis is crucial for development of better drug therapies and appropriate dietary intervention for type 2 diabetes.

Effect of exogenously administered glucagon versus spontaneous endogenous counter-regulation on glycaemic recovery from insulin-induced hypoglycaemia in patients with type 2 diabetes treated with a novel glucokinase activator, AZD1656, and metformin.

AIMS: To study the effect of exogenous i.m. glucagon on recovery from controlled insulin-induced hypoglycaemia in patients with type 2 diabetes treated with the novel glucokinase activator AZD1656, in combination with metformin. METHODS: This was a single-centre randomized, open, two-way crossover phase I, automated glucose clamp (Biostator(®); Life Science Instruments, Elkhart, MD, USA) study (NCT00817271) in eight patients (seven men and one woman, mean age 58.6 years, body mass index 28.1 kg/m(2)). All patients received a stable dose of metformin twice daily, ranging from 1000 to 2250 mg. A 2-day titration phase commenced with 40 mg AZD1656 twice daily, escalating to 80 mg twice daily if tolerated. This was followed by a single dose of 80 or 160 mg AZD1656, administered on days 5 and 8 when metabolic studies were performed. After an overnight fast on days 5 and 8, controlled hypoglycaemia was induced using an exogenous i.v. infusion of insulin. Plasma glucose was lowered in a stepwise fashion over 3 h to attain a target nadir of 2.7 mmol/l. This was sustained for 30 min, at the end of which the hypoglycaemic clamp was released. In random sequence, patients either received an i.m. injection of 1 mg glucagon or were allowed to recover from hypoglycaemia by endogenous counter-regulation. To avoid prolonged hypoglycaemia, a reverse glucose clamp was applied from 4 to 6 h post-dose. RESULTS: Three patients received 40 mg AZD1656 twice daily and five patients 80 mg twice daily. Mean plasma glucose at 20 min after release of the hypoglycaemic clamp was significantly lower (3.1 ± 0.3 mmol/l) for AZD1656 alone than for AZD1656 + glucagon (4.9 ± 0.8 mmol/l; p < 0.001 between the groups). Catecholamine and cortisol responses were similar on the AZD1656 + glucagon and AZD alone study days. Growth hormone response was 18% lower for AZD1656 alone (p = 0.01), consistent with the effect of a pharmacological dose of glucagon on growth hormone secretion. No safety or tolerability concerns were observed during treatment with AZ1656. CONCLUSIONS: Exogenous glucagon was effective as a rescue treatment for hypoglycaemia induced during treatment with AZD1656, given in combination with metformin in patients with type 2 diabetes.

A patent review of glucokinase activators and disruptors of the glucokinase--glucokinase regulatory protein interaction: 2011-2014.

INTRODUCTION: Glucokinase (GK) is a key regulator of glucose homeostasis, and development of small molecule activators of this enzyme represents a promising new approach for the treatment of type 2 diabetes mellitus. AREAS COVERED: This manuscript reviews small molecule patent disclosures between late 2011 and February 2014 for both GK activators (GKAs) and GK-glucokinase regulatory protein (GK-GKRP) disruptors. The review is organized by company and structural class. EXPERT OPINION: The field of GKA research continues to progress, driven by research across many organizations. To date, > 20 candidates have entered clinical development with the most advanced in Phase II trials. Despite promising efficacy, a significant number of early candidates have been discontinued for various reasons including increased risk of hypoglycemia and lack of durability. Recent work in the field has focused on liver-selective activators, which have shown lower hypoglycemia risk, including the development of novel GK-GKRP disruptors that act to indirectly increase hepatic GK activity.

CREPE: mathematical model for crosstalking of endothelial cells and hepatocyte metabolism.

The liver shows a close coexistence between endothelial cells and hepatocytes (HepG2). Endothelial cells' main purpose is to protect (HepG2) from blood vessel shear stress, acting as a barrier, but experimental evidence suggests that they could also play a role in regulating (HepG2) glucose metabolism. A well-known singular effect in hepatocyte-endothelial co-cultures is the reduction of glucose consumption respect to (HepG2) in single culture. (HepG2) were shown to reduce their glucose consumption supporting energy needs of endothelial cells. Monti have studied the effects of endothelin-1 (Et-1) on Glucokinase activity in adult rat (HepG2). They observed a reduction in hepatocytes Glucokinase catalytic rate, which is dependent on Et-1 concentration. We developed crosstalking of endothelial cells and hepatocyte metabolism (CREPE) that is a mathematical model of the endothelin-1 mediated crosstalk between HepG2 and endothelial cells (human umbilical vein endothelial cells) in a traditional static co-culture system. CREPE was validated against experimental data, showing good agreement with them. CREPE can be a starting point to develop predictive tools on complex and highly interconnected environments.

A report of 2 new cases of MODY2 and review of the literature: implications in the search for type 2 diabetes drugs.

Glucokinase (GCK) acts as a glucose sensor and stimulates the release of insulin from pancreatic ß-cells and any GCK gene mutations can lead to different forms of diabetes, such as GCK-monogenic diabetes of the young type 2 (MODY2), permanent neonatal diabetes and congenital hyperinsulinism. Many MODY2 causing mutations display a variation in the degree of severity, ranging from mild dietary-restricted forms to more detrimental presentation requiring insulin replacement. The present study reviews known and two novel GCK mutations in terms of molecular perturbation of the GCK atomic structure but also emphasizes the inactivating and activating properties of the GCK as treatment for T2DM. In silico analysis demonstrated that the newly discovered mutation p.Arg447Pro causes structural conformational changes that lead to the destabilization of the functional properties of the protein resulting in the reduction of glucose and MgATP2- affinity. The novel p.Glu440Stop nonsense mutation on the other hand inactivates the cytoplasmic enzymatic activity of the protein as it is responsible for the loss of the C-terminal end of the polypeptide that includes vital glucose-releasing residues. Based on the in silico models of existing structural data we identified several classes of GCK mutations and discuss their relation to disease outcome. GCK has a central role in controlling body glucose homeostasis and therefore is considered an outstanding drug target for developing new antidiabetic therapies using small molecular activators (GKAs). This study emphasizes the importance in understanding how inactivating and activating GCK mutations affect the mechanistic properties of this glucose sensor. Such information can become the basis for drug discovery of therapeutic compounds and the treatment of T2DM by targeting the GCK allosteric activator site.

A model-based approach to predict longitudinal HbA1c, using early phase glucose data from type 2 diabetes mellitus patients after anti-diabetic treatment.

Predicting late phase outcomes from early-phase findings can help inform decisions in drug development. If the measurements in early-phase differ from those in late phase, forecasting is more challenging. In this paper, we present a model-based approach for predicting glycosylated hemoglobin (HbA1c) in late phase using glucose and insulin concentrations from an early-phase study, investigating an anti-diabetic treatment. Two previously published models were used; an integrated glucose and insulin (IGI) model for meal tolerance tests and an integrated glucose-red blood cell-HbA1c (IGRH) model predicting the formation of HbA1c from the average glucose concentration (Cg,av ). Output from the IGI model was used as input to the IGRH model. Parameters of the IGI model and drug effects were estimated using data from a phase1 study in 59 diabetic patients receiving various doses of a glucokinase activator. Cg,av values were simulated according to a Phase 2 study design and used in the IGRH model for predictions of HbA1c. The performance of the model-based approach was assessed by comparing the predicted to the actual outcome of the Phase 2 study. We have shown that this approach well predicts the longitudinal HbA1c response in a 12-week study using only information from a 1-week study where glucose and insulin concentrations were measured.

Dose-ranging study with the glucokinase activator AZD1656 as monotherapy in Japanese patients with type 2 diabetes mellitus.

AIM: To assess the glucose-lowering effects of monotherapy with the glucokinase activator AZD1656 in Japanese patients with type 2 diabetes mellitus. METHODS: This was a randomized, double-blind, placebo-controlled study performed in Japan (NCT01152385). Patients (n = 224) were randomized to AZD1656 (40-200, 20-140 or 10-80 mg titrated doses) or placebo. The primary variable was the placebo-corrected change from baseline to 4 months in glycated haemoglobin (HbA1c). Effects on fasting plasma glucose (FPG) and safety were also assessed. RESULTS: HbA1c was reduced numerically from baseline by 0.3-0.8% with AZD1656 and by 0.1% with placebo over the first 2 months of treatment, after which effects of AZD1656 started to decline. The changes from baseline to 4 months in HbA1c were not significant for the AZD1656 40-200 mg group versus placebo [mean (95% CI) placebo-corrected change: -0.22 (-0.65, 0.20)%; p = 0.30]. Formal significance testing was not carried out for the other two AZD1656 dose groups. A higher percentage of patients on AZD1656 achieved HbA1c ≤ 7% after 4 months versus placebo, but responder rates were low. Results for FPG reflected those for HbA1c. Cases of hypoglycaemia were rare with AZD1656 (one patient) and no safety concerns were raised. CONCLUSIONS: Although initially favourable plasma glucose reductions were observed, there was a loss of effect over time with sustained AZD1656 treatment. The study design did not allow an evaluation of the reasons for this lack of long-term efficacy.

Dose-ranging study with the glucokinase activator AZD1656 in patients with type 2 diabetes mellitus on metformin.

AIM: To investigate the effect of glucokinase activator AZD1656 on glycated haemoglobin (HbA1c) as an add-on to metformin in patients with type 2 diabetes. METHODS: This randomized, double-blind, placebo-controlled study (NCT01020123) was conducted over 4 months with an optional 2-month extension. Patients (n = 458) with HbA1c 7.5-10% were randomized to AZD1656 20 mg (n = 40) or 40 mg (n = 52) fixed doses or 10-140 mg (n = 91) or 20-200 mg (n = 93) titrated doses, placebo (n = 88) or glipizide 5-20 mg titrated (n = 94). Patients (n = 72) with HbA1c >10 and ≤12% received open-label AZD1656 (20-200 mg titrated). Primary outcome was placebo-corrected change in HbA1c from baseline to 4 months of treatment. RESULTS: Significant reductions in HbA1c from baseline to 4 months were observed with blinded AZD1656 10-140 and 20-200 mg versus placebo [mean (95% CI) changes: -0.80 (-1.14; -0.46) and -0.81 (-1.14; -0.47) %, respectively), with similar reductions observed with glipizide. A higher percentage of patients on AZD1656 than on placebo achieved HbA1c ≤7.0 or ≤6.5 % after 4 months. Mean (s.d.) change in HbA1c for open-label AZD1656 (20-200 mg) was -2.8 (1.19) % after 4 months. AZD1656 was well tolerated, with less hypoglycaemia than glipizide. In the extension population, HbA1c was still reduced with AZD1656 versus placebo after 6 months, but the effect of AZD1656 on glucose control was not sustained over time. CONCLUSION: Addition of AZD1656 (individually titrated) to metformin gave significant improvements in glycaemic control up to 4 months, although efficacy diminished over time.