Imeglimin prevents human endothelial cell death by inhibiting mitochondrial permeability transition without inhibiting mitochondrial respiration

Rationale and Design of the Study to Investigate the Metabolic Action of Imeglimin on Patients with Type 2 Diabetes Mellitus (SISIMAI)

INTRODUCTION

Imeglimin is a first-in-class, novel, oral glucose-lowering agent for the treatment of type 2 diabetes mellitus. The efficacy and safety of imeglimin as an antidiabetic agent have been investigated in clinical trials. However, its metabolic effects in humans have not yet been fully elucidated.

METHODS

The Study to InveStIgate the Metabolic Action of Imeglimin on patients with type 2 diabetes mellitus (SISIMAI) is a single-arm intervention study. In this study, we have recruited 25 patients with type 2 diabetes to receive 2000 mg/day imeglimin for 20 weeks. We perform a 75-g oral glucose tolerance test (OGTT) with double-glucose tracers, a two-step hyperinsulinemic-euglycemic clamp with glucose tracer, ectopic fat measurement by proton magnetic resonance spectroscopy, visceral/subcutaneous fat area measurement by magnetic resonance imaging, muscle biopsy, and evaluation of fitness level by cycle ergometer before and after imeglimin administration.

PLANNED OUTCOMES

The primary outcome is the change in area under the curve of glucose levels during the OGTT after 20 weeks of imeglimin treatment. We also calculate the endogenous glucose production, rate of oral glucose appearance, and rate of glucose disappearance from the data during the 75-g OGTT and compare them between pre- and post-treatment. Additionally, we will compare other parameters, such as the changes in tissue-specific insulin sensitivity, ectopic fat accumulation, visceral/subcutaneous fat area accumulation, and fitness level between each point. This is the first study to investigate the organ-specific metabolic action of imeglimin in patients with type 2 diabetes mellitus using the 75-g OGTT with the double tracer method. The results of this study are expected to provide useful information for drug selection based on the pathophysiology of individual patients with type 2 diabetes mellitus.

TRIAL REGISTRATION

jRCTs031210600.

Modern Challenges in Type 2 Diabetes: Balancing New Medications with Multifactorial Care

Type 2 diabetes mellitus (T2DM) is a prevalent chronic metabolic disorder characterized by insulin resistance and progressive beta cell dysfunction, presenting substantial global health and economic challenges. This review explores recent advancements in diabetes management, emphasizing novel pharmacological therapies and their physiological mechanisms. We highlight the transformative impact of Sodium-Glucose Cotransporter 2 inhibitor (SGLT2i) and Glucagon-Like Peptide 1 Receptor Agonist (GLP-1RA), which target specific physiological pathways to enhance glucose regulation and metabolic health. A key focus of this review is tirzepatide, a dual agonist of the glucose-dependent insulinotropic polypeptide (GIP) and GLP-1 receptors. Tirzepatide illustrates how integrating innovative mechanisms with established physiological pathways can significantly improve glycemic control and support weight management. Additionally, we explore emerging treatments such as glimins and glucokinase activators (GKAs), which offer novel strategies for enhancing insulin secretion and reducing glucose production. We also address future perspectives in diabetes management, including the potential of retatrutide as a triple receptor agonist and evolving guidelines advocating for a comprehensive, multifactorial approach to care. This approach integrates pharmacological advancements with essential lifestyle modifications-such as dietary changes, physical activity, and smoking cessation-to optimize patient outcomes. By focusing on the physiological mechanisms of these new therapies, this review underscores their role in enhancing T2DM management and highlights the importance of personalized care plans to address the complexities of the disease. This holistic perspective aims to improve patient quality of life and long-term health outcomes.

Imeglimin modulates mitochondria biology and facilitates mitokine secretion in 3T3-L1 adipocytes

AIMS

Imeglimin, a novel antidiabetic drug, has recently been reported to affect pancreatic β-cells and hepatocytes. Adipose tissue plays a crucial role in systemic metabolism. However, its effect on adipocytes remains unexplored. Herein, we investigated the effects of imeglimin on adipocytes, particularly in the mitochondria.

MAIN METHODS

The 3T3-L1 adipocytes were treated with imeglimin. Mitochondrial respiratory complex I activity and NAD+, NADH, and AMP levels were measured. Protein expression levels were determined by western blotting, mitochondrial DNA and mRNA expression levels were determined using quantitative polymerase chain reaction, and secreted adipocytokine and mitokine levels were determined using adipokine array and enzyme-linked immunosorbent assay.

KEY FINDINGS

Imeglimin inhibited complex I activity, decreased the NAD+/NADH ratio, and increased AMP levels, which were associated with the enhanced phosphorylation of AMP-activated protein kinase. In addition, imeglimin increased the mitochondrial DNA content and levels of mitochondrial transcription factor A and peroxisome proliferator-activated receptor-γ coactivator 1-α mRNA, which were abolished by Ly294002, a phosphoinositide 3-kinase inhibitor. Furthermore, imeglimin facilitated the expression levels of markers of the mitochondrial unfolded protein response, and the gene expression and secretion of two mitokines, fibroblast growth factor 21 and growth differentiation factor 15. The production of both mitokines was transcriptionally regulated and abolished by phosphoinositide 3-kinase and Akt inhibitors.

SIGNIFICANCE

Imeglimin modulates mitochondrial biology in adipocytes and may exert a mitohormetic effect through mitokine secretion.

Novel Therapeutics for Type 2 Diabetes Mellitus-A Look at the Past Decade and a Glimpse into the Future

Cardiovascular disease (CVD) and kidney disease are the main causes of morbidity and mortality in type 2 diabetes mellitus (T2DM). Globally, the incidence of T2DM continues to rise. A substantial increase in the burden of CVD and renal disease, alongside the socioeconomic implications, would be anticipated. Adopting a purely glucose-centric approach focusing only on glycemic targets is no longer adequate to mitigate the cardiovascular risks in T2DM. In the past decade, significant advancement has been achieved in expanding the pharmaceutical options for T2DM, with novel agents such as the sodium-glucose cotransporter type 2 (SGLT2) inhibitors and glucagon-like peptide receptor agonists (GLP-1 RAs) demonstrating robust evidence in cardiorenal protection. Combinatorial approaches comprising multiple pharmacotherapies combined in a single agent are an emerging and promising way to not only enhance patient adherence and improve glycemic control but also to achieve the potential synergistic effects for greater cardiorenal protection. In this review, we provide an update on the novel antidiabetic agents in the past decade, with an appraisal of the mechanisms contributing to cardiorenal protection. Additionally, we offer a glimpse into the landscape of T2DM management in the near future by providing a comprehensive summary of upcoming agents in early-phase trials.

Exploring new mechanisms of Imeglimin in diabetes treatment: Amelioration of mitochondrial dysfunction

With the increasing prevalence of type 2 diabetes mellitus (T2DM), it has become critical to identify effective treatment strategies. In recent years, the novel oral hypoglycaemic drug Imeglimin has attracted much attention in the field of diabetes treatment. The mechanisms of its therapeutic action are complex and are not yet fully understood by current research. Current evidence suggests that pancreatic β-cells, liver, and skeletal muscle are the main organs in which Imeglimin lowers blood glucose levels and that it acts mainly by targeting mitochondrial function, thereby inhibiting hepatic gluconeogenesis, enhancing insulin sensitivity, promoting pancreatic β-cell function, and regulating energy metabolism. There is growing evidence that the drug also has a potentially volatile role in the treatment of diabetic complications, including metabolic cardiomyopathy, diabetic vasculopathy, and diabetic neuroinflammation. According to available clinical studies, its efficacy and safety profile are more evident than other hypoglycaemic agents, and it has synergistic effects when combined with other antidiabetic drugs, and also has potential in the treatment of T2DM-related complications. This review aims to shed light on the latest research progress in the treatment of T2DM with Imeglimin, thereby providing clinicians and researchers with the latest insights into Imeglimin as a viable option for the treatment of T2DM.

Imeglimin mitigates the accumulation of dysfunctional mitochondria to restore insulin secretion and suppress apoptosis of pancreatic β-cells from db/db mice

Mitochondrial dysfunction in pancreatic β-cells leads to impaired glucose-stimulated insulin secretion (GSIS) and type 2 diabetes (T2D), highlighting the importance of autophagic elimination of dysfunctional mitochondria (mitophagy) in mitochondrial quality control (mQC). Imeglimin, a new oral anti-diabetic drug that improves hyperglycemia and GSIS, may enhance mitochondrial activity. However, chronic imeglimin treatment's effects on mQC in diabetic β-cells are unknown. Here, we compared imeglimin, structurally similar anti-diabetic drug metformin, and insulin for their effects on clearance of dysfunctional mitochondria through mitophagy in pancreatic β-cells from diabetic model db/db mice and mitophagy reporter (CMMR) mice. Pancreatic islets from db/db mice showed aberrant accumulation of dysfunctional mitochondria and excessive production of reactive oxygen species (ROS) along with markedly elevated mitophagy, suggesting that the generation of dysfunctional mitochondria overwhelmed the mitophagic capacity in db/db β-cells. Treatment with imeglimin or insulin, but not metformin, reduced ROS production and the numbers of dysfunctional mitochondria, and normalized mitophagic activity in db/db β-cells. Concomitantly, imeglimin and insulin, but not metformin, restored the secreted insulin level and reduced β-cell apoptosis in db/db mice. In conclusion, imeglimin mitigated accumulation of dysfunctional mitochondria through mitophagy in diabetic mice, and may contribute to preserving β-cell function and effective glycemic control in T2D.

Imeglimin Exhibits Novel Anti-Inflammatory Effects on High-Glucose-Stimulated Mouse Microglia through ULK1-Mediated Suppression of the TXNIP-NLRP3 Axis

Type 2 diabetes mellitus (T2DM) is an epidemiological risk factor for dementia and has been implicated in multifactorial pathologies, including neuroinflammation. In the present study, we aimed to elucidate the potential anti-inflammatory effects of imeglimin, a novel antidiabetic agent, on high-glucose (HG)-stimulated microglia. Mouse microglial BV2 cells were stimulated with HG in the presence or absence of imeglimin. We examined the effects of imeglimin on the levels of proinflammatory cytokines, intracellular reactive oxygen species (ROS), mitochondrial integrity, and components related to the inflammasome or autophagy pathways in these cells. Our results showed that imeglimin suppressed the HG-induced production of interleukin-1beta (IL-1β) by reducing the intracellular ROS levels, ameliorating mitochondrial dysfunction, and inhibiting the activation of the thioredoxin-interacting protein (TXNIP)-NOD-like receptor family pyrin domain containing 3 (NLRP3) axis. Moreover, the inhibitory effects of imeglimin on the TXNIP-NLRP3 axis depended on the imeglimin-induced activation of ULK1, which also exhibited novel anti-inflammatory effects without autophagy induction. These findings suggest that imeglimin exerted novel suppressive effects on HG-stimulated microglia through the ULK1-TXNIP-NLRP3 axis, and may, thereby, contribute to the development of innovative strategies to prevent T2DM-associated cognitive impairment.

Mitochondrial Dysfunction and Imeglimin: A New Ray of Hope for the Treatment of Type-2 Diabetes Mellitus

Diabetes is a rapidly growing health challenge and epidemic in many developing countries, including India. India, being the diabetes capital of the world, has the dubious dual distinction of being the leading nations for both undernutrition and overnutrition. Diabetes prevalence has increased in both rural and urban areas, affected the younger population and increased the risk of complications and economic burden. These alarming statistics ring an alarm bell to achieve glycemic targets in the affected population in order to decrease diabetes-related morbidity and mortality. In the recent years, diabetes pathophysiology has been extended from an ominous triad through octet and dirty dozen etc. There is a new scope to target multiple pathways at the molecular level to achieve a better glycemic target and further prevent micro- and macrovascular complications. Mitochondrial dysfunction has a pivotal role in both β-cell failure and insulin resistance. Hence, targeting this molecular pathway may help with both insulin secretion and peripheral tissue sensitization to insulin. Imeglimin is the latest addition to our anti-diabetic armamentarium. As imeglimin targets, this root cause of defective energy metabolism and insulin resistance makes it a new add-on therapy in different diabetic regimes to achieve the proper glycemic targets. Its good tolerability and efficacy profiles in recent studies shows a new ray of hope in the journey to curtail diabetes-related morbidity.

Efficacy, safety and tolerability of imeglimin in patients with type 2 diabetes mellitus: A meta-analysis of randomized controlled trials

AIMS/INTRODUCTION

This meta-analysis aimed to evaluate the efficacy and safety/tolerability of imeglimin, a novel oral antihyperglycemic agent, administered as monotherapy and adjunctive therapy in patients with type 2 diabetes mellitus.

MATERIALS AND METHODS

Parallel-group randomized controlled trials comparing imeglimin with placebo in adults with type 2 diabetes mellitus were included. Risk ratios or weighted mean differences (WMD) and 95% confidence intervals (CIs) were calculated using random effects models. The primary outcome for efficacy was the change in glycated hemoglobin (HbA1c). Secondary outcomes included other efficacy-related outcomes, specific adverse events, and changes in body weight and lipid parameters.

RESULTS

Nine randomized controlled trials (n = 1,655) were included. When analyzed by dose, there was a significant difference in glycated hemoglobin (%) between imeglimin monotherapy and placebo at doses >1,000 mg twice daily (1,000 mg: studies N = 3, patients n = 517, WMD = -0.714, P < 0.001; 1,500 mg: N = 5, n = 448, WMD = -0.531, P = 0.020; 2,000 mg: N = 1, n = 149, WMD = -0.450, P = 0.005). Imeglimin adjunctive therapy significantly improved glycated hemoglobin over placebo at doses of 1,000 mg (N = 1, n = 214, WMD = -0.600, P < 0.001) and 1,500 mg (N = 2, n = 324, WMD = -0.576, P < 0.001). Subgroup analysis of the primary outcome showed that imeglimin was effective regardless of chronic kidney disease category, with studies carried out in Japan and in patients with lower body mass index showing a trend toward improved imeglimin efficacy. There were no significant differences between imeglimin and placebo in the risk of all-cause discontinuation and the proportion of patients who presented with at least one adverse event.

CONCLUSIONS

Imeglimin is efficacious, safe, and well tolerated as monotherapy and adjunctive therapy.

The potential mechanism of gut microbiota-microbial metabolites-mitochondrial axis in progression of diabetic kidney disease

Diabetic kidney disease (DKD), has become the main cause of end-stage renal disease (ESRD) worldwide. Lately, it has been shown that the onset and advancement of DKD are linked to imbalances of gut microbiota and the abnormal generation of microbial metabolites. Similarly, a body of recent evidence revealed that biological alterations of mitochondria ranging from mitochondrial dysfunction and morphology can also exert significant effects on the occurrence of DKD. Based on the prevailing theory of endosymbiosis, it is believed that human mitochondria originated from microorganisms and share comparable biological characteristics with the microbiota found in the gut. Recent research has shown a strong correlation between the gut microbiome and mitochondrial function in the occurrence and development of metabolic disorders. The gut microbiome's metabolites may play a vital role in this communication. However, the relationship between the gut microbiome and mitochondrial function in the development of DKD is not yet fully understood, and the role of microbial metabolites is still unclear. Recent studies are highlighted in this review to examine the possible mechanism of the gut microbiota-microbial metabolites-mitochondrial axis in the progression of DKD and the new therapeutic approaches for preventing or reducing DKD based on this biological axis in the future.

Imeglimin: A Clinical Pharmacology Review

Imeglimin (PXL008, EMD-387008, Twymeeg®) is a first-in-class novel oral hypoglycemic agent, launched in Japan, for the treatment of type 2 diabetes mellitus. Its mechanism of action targets mitochondrial bioenergetics to ameliorate insulin resistance and to enhance β-cell function. This review summarizes the properties underlying the pharmacokinetic profile of imeglimin, a small cationic drug belonging to the tetrahydrotriazine chemical class, with a complex mechanism of absorption involving an active transport through organic cation transporters (OCTs). Imeglimin absorption decreases when dose increases due to the saturation of the active uptake transport. Post absorption, imeglimin is rapidly and primarily distributed to organs and tissues, and has a half-life ranging from 9.03 to 20.2 h. Plasma protein binding of imeglimin is low, which explains the rapid distribution to the organs observed in all species. Imeglimin is excreted unchanged in urine, indicating a low extent of metabolism. Imeglimin is a substrate of multidrug and toxic compound extrusion (MATE) 2-K and a substrate and inhibitor of OCT1, OCT2, and MATE1. Clinical drug-drug interaction studies confirmed the absence of relevant clinical interaction with substrates or inhibitors of these transporters. Overall, the drug-drug interaction potential of imeglimin is low. Its pharmacokinetics profile has also been characterized in special populations, showing no influence of mild and moderate hepatic impairment but an impact of renal function on imeglimin renal clearance. Dosage adjustment is thus required in moderately and severely renally impaired patients. Imeglimin pharmacokinetics was shown to be insensitive to ethnicity and food intake and to have no effect on QTcF interval.

Glucose-Lowering Effects of Imeglimin and Its Possible Beneficial Effects on Diabetic Complications

Mitochondrial dysfunction is a prominent pathological feature of type 2 diabetes, which contributes to β-cell mass reduction and insulin resistance. Imeglimin is a novel oral hypoglycemic agent with a unique mechanism of action targeting mitochondrial bioenergetics. Imeglimin reduces reactive oxygen species production, improves mitochondrial function and integrity, and also improves the structure and function of endoplasmic reticulum (ER), changes which enhance glucose-stimulated insulin secretion and inhibit the apoptosis of β-cells, leading to β-cell mass preservation. Further, imeglimin inhibits hepatic glucose production and ameliorates insulin sensitivity. Clinical trials into the effects of imeglimin monotherapy and combination therapy exhibited an excellent hypoglycemic efficacy and safety profile in type 2 diabetic patients. Mitochondrial impairment is closely associated with endothelial dysfunction, which is a very early event in atherosclerosis. Imeglimin improved endothelial dysfunction in patients with type 2 diabetes via both glycemic control-dependent and -independent mechanisms. In experimental animals, imeglimin improved cardiac and kidney function via an improvement in mitochondrial and ER function or/and an improvement in endothelial function. Furthermore, imeglimin reduced ischemia-induced brain damage. In addition to glucose-lowering effects, imeglimin can be a useful therapeutic option for diabetic complications in type 2 diabetic patients.

Anti-Diabetic Therapy and Heart Failure: Recent Advances in Clinical Evidence and Molecular Mechanism

Diabetic patients have a two- to four-fold increase in the risk of heart failure (HF), and the co-existence of diabetes and HF is associated with poor prognosis. In randomized clinical trials (RCTs), compelling evidence has demonstrated the beneficial effects of sodium-glucose co-transporter-2 inhibitors on HF. The mechanism includes increased glucosuria, restored tubular glomerular feedback with attenuated renin-angiotensin II-aldosterone activation, improved energy utilization, decreased sympathetic tone, improved mitochondria calcium homeostasis, enhanced autophagy, and reduced cardiac inflammation, oxidative stress, and fibrosis. The RCTs demonstrated a neutral effect of the glucagon-like peptide receptor agonist on HF despite its weight-reducing effect, probably due to it possibly increasing the heart rate via increasing cyclic adenosine monophosphate (cAMP). Observational studies supported the markedly beneficial effects of bariatric and metabolic surgery on HF despite no current supporting evidence from RCTs. Bromocriptine can be used to treat peripartum cardiomyopathy by reducing the harmful cleaved prolactin fragments during late pregnancy. Preclinical studies suggest the possible beneficial effect of imeglimin on HF through improving mitochondrial function, but further clinical evidence is needed. Although abundant preclinical and observational studies support the beneficial effects of metformin on HF, there is limited evidence from RCTs. Thiazolidinediones increase the risk of hospitalized HF through increasing renal tubular sodium reabsorption mediated via both the genomic and non-genomic action of PPARγ. RCTs suggest that dipeptidyl peptidase-4 inhibitors, including saxagliptin and possibly alogliptin, may increase the risk of hospitalized HF, probably owing to increased circulating vasoactive peptides, which impair endothelial function, activate sympathetic tones, and cause cardiac remodeling. Observational studies and RCTs have demonstrated the neutral effects of insulin, sulfonylureas, an alpha-glucosidase inhibitor, and lifestyle interventions on HF in diabetic patients.

Development of Imeglimin Electrospun Nanofibers as a Potential Buccal Antidiabetic Therapeutic Approach

The prevalence of type 2 diabetes (T2D) has been growing worldwide; hence, safe and effective antidiabetics are critically warranted. Recently, imeglimin, a novel tetrahydrotriazene compound, has been approved for use in T2D patients in Japan. It has shown promising glucose-lowering properties by improving pancreatic beta-cell function and peripheral insulin sensitivity. Nevertheless, it has several drawbacks, including suboptimal oral absorption and gastrointestinal (GI) discomfort. Therefore, this study aimed to fabricate a novel formulation of imeglimin loaded into electrospun nanofibers to be delivered through the buccal cavity to overcome the current GI-related adverse events and to provide a convenient route of administration. The fabricated nanofibers were characterized for diameter, drug-loading (DL), disintegration, and drug release profiles. The data demonstrated that the imeglimin nanofibers had a diameter of 361 ± 54 nm and DL of 23.5 ± 0.2 μg/mg of fibers. The X-ray diffraction (XRD) data confirmed the solid dispersion of imeglimin, favoring drug solubility, and release with improved bioavailability. The rate of drug-loaded nanofibers disintegration was recorded at 2 ± 1 s, indicating the rapid disintegration ability of this dosage form and its suitability for buccal delivery, with a complete drug release after 30 min. The findings of this study suggest that the developed imeglimin nanofibers have the potential to be given via the buccal route, thereby achieving optimal therapeutic outcomes and improving patient compliance.

Mitochondrion: A bridge linking aging and degenerative diseases

Aging is a natural process, characterized by progressive loss of physiological integrity, impaired function, and increased vulnerability to death. For centuries, people have been trying hard to understand the process of aging and find effective ways to delay it. However, limited breakthroughs have been made in anti-aging area. Since the hallmarks of aging were summarized in 2013, increasing studies focus on the role of mitochondrial dysfunction in aging and aging-related degenerative diseases, such as neurodegenerative diseases, osteoarthritis, metabolic diseases, and cardiovascular diseases. Accumulating evidence indicates that restoring mitochondrial function and biogenesis exerts beneficial effects in extending lifespan and promoting healthy aging. In this paper, we provide an overview of mitochondrial changes during aging and summarize the advanced studies in mitochondrial therapies for the treatment of degenerative diseases. Current challenges and future perspectives are proposed to provide novel and promising directions for future research.

Improving the Effects of Imeglimin on Endothelial Function: A Prospective, Single-Center, Observational Study

INTRODUCTION

Endothelial dysfunction is a risk factor for cardiovascular disease in patients with diabetes. We hypothesized that imeglimin, a novel oral hypoglycemic agent, would improve endothelial function.

METHODS

In this study, imeglimin was administered to patients with type 2 diabetes and HbA1c ≥ 6.5% who were not receiving insulin therapy. A meal tolerance test (592 kcal, glucose 75.0 g, fat 28.5 g) was performed before and 3 months after administration, and endothelial function, blood glucose, insulin, glucagon, and triglycerides were evaluated. Endothelial function was assessed by flow-mediated dilation (FMD).

RESULTS

Twelve patients (50% male) with a median age of 55.5 years old (interquartile range [IQR] 51.3-66.0) were enrolled. Fasting FMD did not differ before or 3 months after imeglimin administration (from 6.1 [3.9-8.5] to 6.6 [3.9-9.0], p = 0.092), but 2 h postprandial FMD was significantly improved 3 months after imeglimin administration (from 2.3 [1.9-3.4] to 2.9 [2.4-4.7], p = 0.013). In terms of the glucose profile, imeglimin administration significantly improved HbA1c (from 7.2 ± 0.6% to 6.9 ± 0.6%, p = 0.007), fasting glucose (from 138 ± 19 mg/dL to 128 ± 20 mg/dL, p = 0.020), and 2 h postprandial glucose (from 251 ± 47 mg/dL to 215 ± 68 mg/dL, p = 0.035). The change in 2 h postprandial FMD between before and 3 months after imeglimin administration (Δ2 h postprandial FMD) was negatively correlated with Δ2 h postprandial glucose (r = - 0.653, p = 0.021) in a univariate correlation coefficient analysis. Both patients with and without decreased postprandial glucose 3 months after imeglimin administration had improved postprandial FMD.

CONCLUSION

In this small study, imeglimin administration improved 2 h postprandial FMD. Both glycemic control-dependent and -independent mechanisms might contribute to improved endothelial function.

TRIAL REGISTRATION

This research was registered in the University Hospital Medical Information Network (UMIN, UMIN000046311).

Add-on imeglimin versus metformin dose escalation regarding glycemic control in patients with type 2 diabetes treated with a dipeptidyl peptidase-4 inhibitor plus low-dose metformin: study protocol for a multicenter, prospective, randomized, open-label, parallel-group comparison study (MEGMI study)

INTRODUCTION

Imeglimin is a novel anti-hyperglycemic drug that improves both insulin resistance and insulin secretion. The effects of imeglimin on glycemic control were confirmed in phase III clinical trials, but little is known about its effectiveness in daily clinical practice settings, especially compared with metformin. Therefore, we aim to clarify the efficacy of imeglimin in patients with type 2 diabetes (T2D) being treated with a dipeptidyl peptidase-4 (DPP-4) inhibitor plus low-dose metformin.

RESEARCH DESIGN AND METHODS

This is a multicenter, randomized, prospective, open-label, parallel-group trial. Seventy participants with T2D treated with a DPP-4 inhibitor plus metformin (500-1000 mg/day) for more than 12 weeks and a glycated hemoglobin (HbA1c) level of 52-85 mmol/mol (7.0%-9.9%) will be randomized to receive add-on imeglimin 1000 mg two times per day or metformin dose escalation for 24 weeks. Biochemical analyses and physical assessments will be performed at baseline and at the end of the study, and adverse events will be recorded. The primary endpoint is the change in HbA1c after 24 weeks. The secondary endpoints comprise the changes in blood pressure, pulse rate, body weight, abdominal circumference, and other laboratory parameters; the relationship between improvements of biological parameters including glycemic control and patient background characteristics; and side effects.

RESULTS

This study will reveal new insights into the incorporation of imeglimin into the diabetes treatment strategy.

CONCLUSIONS

This will be the first randomized controlled trial to compare the efficacy of adding imeglimin versus metformin dose escalation on glycemic control in patients with T2D.

TRIAL REGISTRATION NUMBER

jRCT1011220005.

Efficacy and safety of imeglimin add-on to insulin monotherapy in Japanese patients with type 2 diabetes (TIMES 3): A randomized, double-blind, placebo-controlled phase 3 trial with a 36-week open-label extension period

AIMS

To evaluate the efficacy and safety of imeglimin for up to 52 weeks as combination therapy with insulin in Japanese patients with type 2 diabetes.

MATERIALS AND METHODS

This double-blind, randomized, parallel-group phase 3 trial was performed at 35 sites in Japan. Eligible patients were individuals aged ≥20 years with type 2 diabetes and inadequate glycaemic control with insulin. Patients were randomly assigned (1:1) to either imeglimin (1000 mg twice daily) or matched placebo, in combination with insulin, for 16 weeks. In a subsequent 36-week, open-label extension period, all patients received imeglimin 1000 mg twice daily. The primary endpoint was change in mean glycated haemoglobin (HbA1c) from baseline to week 16.

RESULTS

In all, 108 and 107 patients were randomly assigned to treatment with imeglimin 1000 mg twice daily or placebo, respectively. Compared with placebo, the adjusted mean difference in change from baseline HbA1c at Week 16 was -0.60% (95% confidence interval [CI] -0.80 to -0.40; P < 0.0001). This decrease was sustained up to 52 weeks with a mean decrease of -0.64% (95% CI -0.82 to -0.46) versus baseline. The incidence of patients experiencing adverse events and serious adverse events was similar in the two treatment groups. The number of patients experiencing hypoglycaemia was similar in the two treatment groups. In patients receiving imeglimin, all hypoglycaemic events were mild in severity; no episodes required assistance.

CONCLUSIONS

Imeglimin significantly improved HbA1c in Japanese patients with insufficiently controlled type 2 diabetes by insulin and had a similar safety profile to placebo. The efficacy of imeglimin on top of insulin was sustained for 52 weeks. Imeglimin represents a potential new treatment option for this population as add-on to insulin therapy.

Mitochondrial and metabolic dysfunction in ageing and age-related diseases

Organismal ageing is accompanied by progressive loss of cellular function and systemic deterioration of multiple tissues, leading to impaired function and increased vulnerability to death. Mitochondria have become recognized not merely as being energy suppliers but also as having an essential role in the development of diseases associated with ageing, such as neurodegenerative and cardiovascular diseases. A growing body of evidence suggests that ageing and age-related diseases are tightly related to an energy supply and demand imbalance, which might be alleviated by a variety of interventions, including physical activity and calorie restriction, as well as naturally occurring molecules targeting conserved longevity pathways. Here, we review key historical advances and progress from the past few years in our understanding of the role of mitochondria in ageing and age-related metabolic diseases. We also highlight emerging scientific innovations using mitochondria-targeted therapeutic approaches.

Long-term safety and efficacy of imeglimin as monotherapy or in combination with existing antidiabetic agents in Japanese patients with type 2 diabetes (TIMES 2): A 52-week, open-label, multicentre phase 3 trial

AIM

To evaluate the safety and efficacy of imeglimin for 52 weeks as monotherapy or combination therapy with existing antidiabetic agents in Japanese patients with type 2 diabetes.

MATERIALS AND METHODS

TIMES 2 was a phase 3, pivotal, open-label trial including patients with type 2 diabetes inadequately controlled despite diet/exercise or despite treatment with a single agent from one of several available classes of antidiabetic drugs along with diet/exercise. All patients received imeglimin 1000 mg twice-daily orally for 52 weeks as monotherapy or combination therapy. The primary endpoint was safety (adverse events, laboratory results, ECG). The secondary endpoints were changes from baseline in HbA1c and fasting plasma glucose at week 52.

RESULTS

A total of 714 patients received the following treatments: imeglimin monotherapy (n = 134), combination with an α-glucosidase inhibitor (n = 64), biguanide (n = 64), dipeptidyl peptidase-4 inhibitor (DPP4-I; n = 63), glinide (n = 64), glucagon-like peptide-1 receptor agonist (GLP1-RA; n = 70), sodium-glucose co-transporter-2 inhibitor (n = 63), sulphonylurea (n = 127), or thiazolidinedione (n = 65). The percentage of patients experiencing at least one treatment emergent adverse event (TEAE) was 75.5%. Most of these events were mild or moderate in intensity. Serious TEAEs, none of them related to the study drug, occurred in 5.6% of all patients. No clinically significant changes in ECG, vital signs, physical examination, or laboratory tests were noted in any groups. At week 52, HbA1c decreased by 0.46% with imeglimin monotherapy, by 0.56%-0.92% with imeglimin as oral combination therapy, and by 0.12% with injectable GLP1-RA combination therapy. The greatest net HbA1c reduction (0.92%) occurred in patients receiving a DPP4-I in combination with imeglimin.

CONCLUSIONS

Imeglimin provides well-tolerated, long-term safety and efficacy in both monotherapy and oral combination therapy in Japanese patients with type 2 diabetes.

Reduced lactic acidosis risk with Imeglimin: Comparison with Metformin

The global prevalence of type 2 diabetes (T2D) is expected to exceed 642 million people by 2040. Metformin is a widely used biguanide T2D therapy, associated with rare but serious events of lactic acidosis, in particular with predisposing conditions (e.g., renal failure or major surgery). Imeglimin, a recently approved drug, is the first in a new class (novel mode of action) of T2D medicines. Although not a biguanide, Imeglimin shares a chemical moiety with Metformin and also modulates mitochondrial complex I activity, a potential mechanism for Metformin‐mediated lactate accumulation. We interrogated the potential for Imeglimin to induce lacticacidosis in relevant animal models and further assessed differences in key mechanisms known for Metformin's effects. In a dog model of major surgery, Metformin or Imeglimin (30–1000 mg/kg) was acutely administered, only Metformin‐induced lactate accumulation and pH decrease leading to lactic acidosis with fatality at the highest dose. Rats with gentamycin‐induced renal insufficiency received Metformin or Imeglimin (50–100 mg/kg/h), only Metformin increased lactatemia and H⁺ concentrations with mortality at higher doses. Plasma levels of Metformin and Imeglimin were similar in both models. Mice were chronically treated with Metformin or Imeglimin 200 mg/kg bid. Only Metformin produced hyperlactatemia after acute intraperitoneal glucose loading. Ex vivo measurements revealed higher mitochondrial complex I inhibition with Metformin versus slight effects with Imeglimin. Another mechanism implicated in Metformin's effects on lactate production was assessed: in isolated rat, liver mitochondria exposed to Imeglimin or Metformin, only Metformin (50–250 µM) inhibited the mitochondrial glycerol‐3‐phosphate dehydrogenase (mGPDH). In liver samples from chronically treated mice, measured mGPDH activity was lower with Metformin versus Imeglimin. These data indicate that the risk of lactic acidosis with Imeglimin treatment may be lower than with Metformin and confirm that the underlying mechanisms of action are distinct, supporting its potential utility for patients with predisposing conditions.

[Imeglimin: features of the mechanism of action and potential benefits]

Imeglimin is the first drug in a new class of tetrahydrotriazine-containing oral hypoglycemic agents called «glimines». Its mechanism of action is aimed at achieving a double effect, firstly, to improve the function of beta cells of the pancreas, and secondly, to enhance the action of insulin in key tissues, including the liver and skeletal muscles. At the cellular level, imeglimin modulates mitochondrial function, which leads to an improvement in cellular energy metabolism, as well as to the protection of cells from death in conditions of excessive accumulation of reactive oxygen species. It is important to note that the mechanism of action of imeglimin differs from existing drugs used for the treatment of type 2 diabetes mellitus. Like glucagon-like peptide-1 receptor agonists, imeglimin enhances insulin secretion in an exclusively glucose-dependent manner, but their mechanism of action at the cellular level diverges. Sulfonylureas and glinides function by closing ATP-sensitive potassium channels to release insulin, which is also different from imeglimin. Compared with metformin, the effect of imeglimine is also significantly different. Other major classes of oral antihypertensive agents, such as sodium-glucose transporter-2 inhibitors, thiazolidinediones and α glucosidase inhibitors mediate their action through mechanisms that do not overlap with imeglimine. Given such differences in the mechanisms of action, imeglimin can be used as part of combination therapy, for example with sitagliptin and metformin. The imeglimine molecule is well absorbed (Tmax-4), and the half-life is 5-6 hours, is largely excreted through the kidneys, and also has no clinically significant interactions with either metformin or sitagliptin.

Imeglimin Ameliorates β-Cell Apoptosis by Modulating the Endoplasmic Reticulum Homeostasis Pathway

The effects of imeglimin, a novel antidiabetes agent, on β-cell function remain unclear. Here, we unveiled the impact of imeglimin on β-cell survival. Treatment with imeglimin augmented mitochondrial function, enhanced insulin secretion, promoted β-cell proliferation, and improved β-cell survival in mouse islets. Imeglimin upregulated the expression of endoplasmic reticulum (ER)-related molecules, including Chop (Ddit3), Gadd34 (Ppp1r15a), Atf3, and Sdf2l1, and decreased eIF2α phosphorylation after treatment with thapsigargin and restored global protein synthesis in β-cells under ER stress. Imeglimin failed to protect against ER stress-induced β-cell apoptosis in CHOP-deficient islets or in the presence of GADD34 inhibitor. Treatment with imeglimin showed a significant decrease in the number of apoptotic β-cells and increased β-cell mass in Akita mice. Imeglimin also protected against β-cell apoptosis in both human islets and human pluripotent stem cell-derived β-like cells. Taken together, imeglimin modulates the ER homeostasis pathway, which results in the prevention of β-cell apoptosis both in vitro and in vivo.

Skeletal muscle as a treatment target for older adults with diabetes mellitus: The importance of a multimodal intervention based on functional category

Although the lifespan of people with diabetes has increased in many countries, the age-related increase in comorbidities (sarcopenia, frailty and disabilities) and diabetic complications has become a major issue. Diabetes accelerates the aging of skeletal muscles and blood vessels through mechanisms, such as increased oxidative stress, chronic inflammation, insulin resistance, mitochondrial dysfunction, genetic polymorphism (fat mass and obesity-associated genes) and accumulation of advanced glycation end-products. Diabetes is associated with early onset, and progression of muscle weakness and sarcopenia, thus resulting in diminished daily life function. The type and duration of diabetes, insulin section/resistance, hyperglycemia, diabetic neuropathy, malnutrition and low physical activity might affect muscular loss and weakness. To prevent the decline in daily activities in older adults with diabetes, resistance training or multicomponent exercise should be recommended. To maintain muscle function, optimal energy and sufficient protein intake are necessary. Although no specific drug enhances muscle mass and function, antidiabetic drugs that increase insulin sensitivity or secretion could be candidates for improvement of sarcopenia. The goals of glycemic control for older patients are determined based on three functional categories through an assessment of cognitive function and activities of daily living, and the presence or absence of medications that pose a hypoglycemic risk. As these functional categories are associated with muscle weakness, frailty and mortality risk, providing multimodal interventions (exercise, nutrition, social network or support and optimal medical treatment) is important, starting at the category II stage for maintenance or improvement in daily life functions. Geriatr Gerontol Int 2022; ••: ••-••.

TRC150094, a Novel Mitochondrial Modulator, Reduces Cardio-Metabolic Risk as an Add-On Treatment: a Phase-2, 24-Week, Multi-Center, Randomized, Double-Blind, Clinical Trial

BACKGROUND

TRC150094, a novel mitochondrial modulator, reduces insulin resistance and is expected to improve the trinity of dysglycemia, dyslipidemia, and hypertension. In this multi-dose phase-2 study, we evaluated the safety and efficacy of TRC150094 in diabetic subjects with dyslipidemia receiving standard of care.

METHODS

A randomized, multicenter, double-blind, placebo-controlled, parallel-group, Phase 2 study was conducted in 225 subjects from July 2013 to August 2015. The key inclusion criteria were body mass index of 23-35 kg/m², age between 30 and 65 years, fasting glucose of ≥126 or glycated hemoglobin (HbA1c) of ≥6.4% stabilized on treatment with ≤2 oral hypoglycemic agents, apolipoprotein-B (apo-B) ≥100 mg/dL, serum triglyceride (TG) ≥150 mg/dL, systolic blood pressure (SBP) ≥130 mmHg, and diastolic blood pressure (DBP) ≥85 mmHg with/without antihypertensive treatment. The subjects were randomly assigned to one of three TRC150094 doses (25, 50, or 75 mg) or placebo for 24 weeks. The outcomes assessed included fasting plasma glucose (FPG), insulin, mean arterial blood pressure (MAP), and apoB. In addition, safety and tolerability were assessed.

RESULTS

A reduction for dose up to 50 mg was noted for FPG in the range of 13.9 to 21.7 mg/dL (p < 0.05 for TRC150094 25 and 50 mg), fasting insulin reduction in the range 2.7 to 6.0 mU/L (all doses, p > 0.05), and improved HOMA-IR (-2.0 to -2.5) (all doses, p > 0.05) compared to placebo after 24 weeks of treatment. Furthermore, a significant reduction in MAP in the range 3.1 to 4.2 mmHg (p < 0.05 for TRC150094 25 and 75 mg) was noted. In addition, TRC150094 treatment was weight neutral, had a favorable effect on lowering atherogenic lipid fractions, including non-HDL cholesterol (-6.8 mg/dL at 50 mg dose). Adverse events were mild to moderate in nature and not dose-related. One adverse event not related to treatment led to the discontinuation of the study. Overall, TRC150094 was safe and well tolerated for up to 24 weeks.

CONCLUSION

In this study, TRC150094 treatment in the dose range of 25 to 50 mg showed improvement in various components of CMBCD, ie, dysglycemia, dyslipidemia, and hypertension.

TRIAL REGISTRATION

This study was registered in the Clinical Trial Registry of India. Trial registration number: CTRI/2013/03/003444. Date of registration: 4th March 2013.

Pharmacokinetics of Imeglimin in Caucasian and Japanese Healthy Subjects

BACKGROUND

Imeglimin is a first-in-class novel oral antidiabetic marketed in Japan as TWYMEEG^® to treat type 2 diabetes mellitus. Its mode of action is distinct from all other anti-hyperglycemic classes.

OBJECTIVE

To assess the pharmacokinetic and safety profile of imeglimin in Caucasian and Japanese healthy individuals.

METHODS

Two randomized placebo-controlled phase 1 clinical studies were conducted in Caucasian subjects after single (250-8000 mg) and multiple (250-2000 mg twice daily) ascending doses and in Japanese subjects after single (500-6000 mg) and multiple (500-2000 mg twice daily) ascending doses. Imeglimin plasma and urine concentrations were measured.

RESULTS

All imeglimin doses achieved maximal concentration between 1 and 3.5 h in Caucasians, and 1.5 and 3 h in Japanese subjects. The elimination half-lives (t_1/2) were dose-independent and means ranged between 9.03 and 20.2 h for Caucasians, and 4.45 and 12 h for Japanese subjects. Dose-normalized area under the plasma concentration-time curve decreased with dose in the 250-8000 mg and in the 500-6000 mg dose range in Caucasians and Japanese, respectively, suggesting a dose-dependent but less than dose-proportional effect in imeglimin exposure. Plasma accumulation was minimal following repeated dosing, and food did not affect the pharmacokinetics in either population. Exposures were generally similar between Caucasian and Japanese subjects with less than 20% difference, although there was a tendency for exposures in Japanese to be slightly higher. Imeglimin had an acceptable safety and tolerability profile, with dose-dependent mild gastrointestinal adverse events.

CONCLUSION

Imeglimin was safe and well tolerated in these two phases 1 studies, with pharmacokinetics comparable between the two populations.

CLINICAL TRIAL REGISTRATIONS

EudraCT 2005-001946-18 and 2014-004679-21.

Preservation effect of imeglimin on pancreatic β-cell mass: Noninvasive evaluation using 111In-exendin-4 SPECT/CT imaging and the perspective of mitochondrial involvements

Progressive loss of β-cell mass (BCM) has a pernicious influence on type 2 diabetes mellitus (T2DM); evaluation of BCM has conventionally required an invasive method that provides only cross-sectional data. However, a noninvasive approach to longitudinal assessment of BCM in living subjects using an indium 111-labeled exendin-4 derivative ([Lys12(¹¹¹In-BnDTPA-Ahx)]exendin-4) (¹¹¹In-exendin-4) has been developed recently. Imeglimin is a novel antidiabetic agent that is reported to improve glycemic control and glucose-stimulated insulin secretion (GSIS) via augmentation of mitochondrial function. However, the influence of imeglimin on BCM is not fully understood. We have investigated the effects of imeglimin on BCM in vivo in prediabetic db/db mice using a noninvasive ¹¹¹In-exendin-4 single-photon emission computed tomography/computed tomography (SPECT/CT) technique. During the 5-week study period, imeglimin treatment attenuated the progression of glucose intolerance, and imeglimin-treated mice retained greater BCM than control, which was consistent with the results of ¹¹¹In-exendin-4 SPECT/CT scans. Furthermore, immunohistochemical analysis revealed reduced β-cell apoptosis in the imeglimin-treated db/db mice, and also lowered release of cytosolic cytochrome c protein in the β cells. Furthermore, electron microscopy observation and membrane potential measurement revealed improved structural integrity and membrane potential of the mitochondria of imeglimin-treated islets, respectively. These results demonstrate attenuation of progression of BCM loss in prediabetic db/db mice partly via inhibition of mitochondria-mediated apoptosis.

Efficacy and safety of imeglimin in patients with type 2 diabetes mellitus: A systematic review and meta-analysis of randomized clinical trials

BACKGROUND AND AIM

Imeglimin is a novel tetrahydrotriazine-containing drug suggested as a safe drug for glycemic management in patients with type 2 diabetes mellitus (T2DM). We aimed to 1) evaluate the efficacy of imeglimin on glycemic control and insulin resistance improvement measured by homeostatic model assessment of insulin resistance (HOMA-IR). 2) assess whether the novel drug improves lipid parameters in diabetic patients. 3) compare between different doses regarding safety.

METHODS

We searched PubMed, Cochrane Library, Scopus, Web of Science, Google Scholar, and Wiley through April 25, 2021, for relevant randomized controlled trials comparing different doses of imeglimin supplied as a monotherapy or as add-on therapy versus placebo for adult patients with type 2 diabetes mellitus. Data on glycemic and lipid parameters and adverse events were extracted and pooled in random-effect models using Review Manager version 5.3.

RESULTS

Eight studies comprising 1555 patients with T2DM were included in this study. The overall effect estimate of the meta-analysis showed that the imeglimin group was superior to the control group concerning glycated hemoglobin and fasting plasma glucose (P < 0.00001). However, it did not affect HOMA-IR or lipid parameters, including triglyceride, LDL-C, and HDL-C (all p > 0.05). Regarding safety profile, imeglimin was safe and tolerable with no treatment-emergent or serious adverse events.

CONCLUSIONS

Imeglimin safely improved glycemic control by reducing HbA1c and FPG. However, no beneficial effects regarding insulin resistance measured by HOMA-IR or lipid parameters were observed. Further high-quality RCTs with high dose imeglimin are encouraged to ensure HOMA-IR and lipid parameters results.

Treatment of type 2 diabetes: challenges, hopes, and anticipated successes

Despite the successful development of new therapies for the treatment of type 2 diabetes, such as glucagon-like peptide-1 (GLP-1) receptor agonists and sodium-glucose cotransporter-2 inhibitors, the search for novel treatment options that can provide better glycaemic control and at reduce complications is a continuous effort. The present Review aims to present an overview of novel targets and mechanisms and focuses on glucose-lowering effects guiding this search and developments. We discuss not only novel developments of insulin therapy (eg, so-called smart insulin preparation with a glucose-dependent mode of action), but also a group of drug classes for which extensive research efforts have not been rewarded with obvious clinical impact. We discuss the potential clinical use of the salutary adipokine adiponectin and the hepatokine fibroblast growth factor (FGF) 21, among others. A GLP-1 peptide receptor agonist (semaglutide) is now available for oral absorption, and small molecules activating GLP-1 receptors appear on the horizon. Bariatric surgery and its accompanying changes in the gut hormonal milieu offer a background for unimolecular peptides interacting with two or more receptors (for GLP-1, glucose-dependent insulinotropic polypeptide, glucagon, and peptide YY) and provide more substantial glycaemic control and bodyweight reduction compared with selective GLP-1 receptor agonists. These and additional approaches will help expand the toolbox of effective medications needed for optimising the treatment of well delineated subgroups of type 2 diabetes or help develop personalised approaches for glucose-lowering drugs based on individual characteristics of our patients.

Targeting Mitochondria in Diabetes

Type 2 diabetes (T2D), one of the most prevalent noncommunicable diseases, is often preceded by insulin resistance (IR), which underlies the inability of tissues to respond to insulin and leads to disturbed metabolic homeostasis. Mitochondria, as a central player in the cellular energy metabolism, are involved in the mechanisms of IR and T2D. Mitochondrial function is affected by insulin resistance in different tissues, among which skeletal muscle and liver have the highest impact on whole-body glucose homeostasis. This review focuses on human studies that assess mitochondrial function in liver, muscle and blood cells in the context of T2D. Furthermore, different interventions targeting mitochondria in IR and T2D are listed, with a selection of studies using respirometry as a measure of mitochondrial function, for better data comparison. Altogether, mitochondrial respiratory capacity appears to be a metabolic indicator since it decreases as the disease progresses but increases after lifestyle (exercise) and pharmacological interventions, together with the improvement in metabolic health. Finally, novel therapeutics developed to target mitochondria have potential for a more integrative therapeutic approach, treating both causative and secondary defects of diabetes.

Imeglimin preserves islet β-cell mass in Type 2 diabetic ZDF rats

Objectives

Type 2 diabetes (T2D) is driven by progressive dysfunction and loss of pancreatic β-cell mass. Imeglimin is a first-in-class novel drug candidate that improves glycaemia and glucose-stimulated insulin secretion in preclinical models and patients. Given evidence that imeglimin can attenuate β-cell dysfunction and protect β cells in vitro, we postulated that imeglimin could also exert longer term effects to prevent pancreatic β-cell death and preserve functional β-cell mass in vivo.

Methods

Zucker diabetic fatty (ZDF) male rats were treated by oral gavage with imeglimin at a standard dose of 150 mg/kg or vehicle, twice daily for five weeks. At treatment completion, oral glucose tolerance tests were performed in fasted animals before a thorough histomorphometry and immunohistochemical analysis was conducted on pancreas tissue slices to assess cellular composition and disease status.

Results

Imeglimin treatment significantly improved glucose-stimulated insulin secretion (augmentation of the insulinogenic index) and improved glycaemia. Both basal insulinaemia and pancreatic insulin content were also increased by imeglimin. In ZDF control rats, islet structure was disordered with few β-cells; after imeglimin treatment, islets appeared healthier with more normal morphology in association with a significant increase in insulin-positive β-cells. The increase in β-cell mass was associated with a greater degree of β-cell proliferation in the presence of reduced apoptosis. Unexpectedly, a decrease in as a α-cell mass was also documented due to an apparent antiproliferative effect of imeglimin on this cell type.

Conclusion

In male ZDF rats, chronic imeglimin treatment corrects a paramount component of type 2 diabetes progression: progressive loss of functional β-cell mass. In addition, imeglimin may also moderate a-cell turnover to further ameliorate hyperglycaemia. Cumulatively, these cellular effects suggest that imeglimin may provide for disease modifying effects to preserve functional β-cell mass.

Efficacy and Safety of Imeglimin Monotherapy Versus Placebo in Japanese Patients With Type 2 Diabetes (TIMES 1): A Double-Blind, Randomized, Placebo-Controlled, Parallel-Group, Multicenter Phase 3 Trial

OBJECTIVE

The aim of this study was to investigate the efficacy and safety of imeglimin, the first in a new class of oral antidiabetic agent, in Japanese patients with type 2 diabetes.

RESEARCH DESIGN AND METHODS

This was a double-blind, randomized, parallel-group, placebo-controlled phase 3 trial in 30 sites in Japan. Eligible participants were individuals aged ≥20 years with type 2 diabetes treated with diet and exercise, stable for ≥12 weeks prior to screening, and whose HbA_1c was 7.0-10.0% (53-86 mmol/mol). Patients were randomly assigned (1:1) to either oral imeglimin (1,000 mg twice daily) or matched placebo for 24 weeks. Investigators, participants, and the sponsor of the study remained blinded throughout the trial. The primary end point was the change in mean HbA_1c from baseline to week 24, and the key secondary end point was the percentage of responders (according to two definitions) at week 24.

RESULTS

Between 26 December 2017 and 1 February 2019, 106 and 107 patients were randomly assigned to treatment with imeglimin and placebo, respectively. Compared with placebo, the adjusted mean difference in change from baseline HbA_1c at week 24 was -0.87% (95% CI -1.04 to -0.69 [-9.5 mmol/mol; 95% CI -11.4 to -7.5]; P < 0.0001). Forty-seven (44.3%) patients reported ≥1 adverse event in the imeglimin group versus 48 adverse events (44.9%) in the placebo group.

CONCLUSIONS

Imeglimin significantly improved HbA_1c in Japanese patients with type 2 diabetes compared with placebo and had a similar safety profile to placebo. Imeglimin represents a potential new treatment option for this population.

The mechanism by which imeglimin inhibits gluconeogenesis in rat liver cells

Aims

To understand the mechanism by which imeglimin (a new oral hypoglycemic agent whose phase 3 development program in Japan has now been completed) decreases hepatic glucose production.

Materials and methods

We compared the effect of imeglimin and metformin on glucose production, ATP/ADP ratio, oxygen consumption rate, mitochondrial redox potential and membrane potential in primary rat hepatocytes.

Results

We found that both imeglimin and metformin dose-dependently decreased glucose production and the ATP/ADP ratio. Moreover, they both increased mitochondrial redox potential (assessed by mitochondrial NAD(P)H fluorescence) and decreased membrane potential (assessed by TMRM fluorescence). However, contrary to metformin, which inhibits mitochondrial Complex I, imeglimin did not decrease the oxygen consumption rate in intact cells. By measuring the oxygen consumption of in situ respiratory chain as a function of the concentration of NADH, we observed that imeglimin decreased the affinity of NADH for the respiratory chain but did not affect its Vmax (ie competitive inhibition) whereas metformin decreased both the Vmax and the affinity (ie uncompetitive inhibition).

Conclusions

We conclude that imeglimin induces a kinetic constraint on the respiratory chain that does not affect its maximal activity. This kinetic constraint is offset by a decrease in the mitochondrial membrane potential, which induces a thermodynamic constraint on the ATPase responsible for a decrease in the ATP/ADP ratio.

Mechanism of action of Imeglimin: A novel therapeutic agent for type 2 diabetes

Imeglimin is an investigational first-in-class novel oral agent for the treatment of type 2 diabetes (T2D). Several pivotal phase III trials have been completed with evidence of statistically significant glucose lowering and a generally favourable safety and tolerability profile, including the lack of severe hypoglycaemia. Imeglimin's mechanism of action involves dual effects: (a) amplification of glucose-stimulated insulin secretion (GSIS) and preservation of β-cell mass; and (b) enhanced insulin action, including the potential for inhibition of hepatic glucose output and improvement in insulin signalling in both liver and skeletal muscle. At a cellular and molecular level, Imeglimin's underlying mechanism may involve correction of mitochondrial dysfunction, a common underlying element of T2D pathogenesis. It has been observed to rebalance respiratory chain activity (partial inhibition of Complex I and correction of deficient Complex III activity), resulting in reduced reactive oxygen species formation (decreasing oxidative stress) and prevention of mitochondrial permeability transition pore opening (implicated in preventing cell death). In islets derived from diseased rodents with T2D, Imeglimin also enhances glucose-stimulated ATP generation and induces the synthesis of nicotinamide adenine dinucleotide (NAD+ ) via the 'salvage pathway'. In addition to playing a key role as a mitochondrial co-factor, NAD+ metabolites may contribute to the increase in GSIS (via enhanced Ca++ mobilization). Imeglimin has also been shown to preserve β-cell mass in rodents with T2D. Overall, Imeglimin appears to target a key root cause of T2D: defective cellular energy metabolism. This potential mode of action is unique and has been shown to differ from that of other major therapeutic classes, including biguanides, sulphonylureas and glucagon-like peptide-1 receptor agonists.

Efficacy and safety of imeglimin in Japanese patients with type 2 diabetes: A 24-week, randomized, double-blind, placebo-controlled, dose-ranging phase 2b trial

AIM

To assess the efficacy and safety of imeglimin monotherapy compared with placebo for 24 weeks in Japanese patients with type 2 diabetes (T2D).

MATERIALS AND METHODS

In this 24-week, randomized, double-blind, placebo-controlled, parallel-group, dose-ranging, phase 2b clinical trial, Japanese adults (age ≥ 20 years) with T2D either treatment-naïve or previously treated with one oral antidiabetes agent were eligible for participation. Patients were randomly assigned (1:1:1:1) to receive orally imeglimin 500, 1000 or 1500 mg, or placebo twice-daily over a 24-week period. The primary endpoint was the placebo-adjusted change at week 24 in HbA1c. Safety outcomes were assessed in all patients who received at least one dose of study drug.

RESULTS

A total of 299 patients were randomized to receive double-blind treatment with orally twice-daily placebo (n = 75), imeglimin 500 mg (n = 75), 1000 mg (n = 74) or 1500 mg (n = 75). At week 24, imeglimin significantly decreased HbA1c (difference vs. placebo: imeglimin 500 mg -0.52% [95% CI: -0.77%, -0.27%], imeglimin 1000 mg -0.94% [95% CI: -1.19%, -0.68%], imeglimin 1500 mg -1.00% [95% CI: -1.26%, -0.75%]; P < .0001 for all). Treatment-emergent adverse events were reported for 68.0%, 62.2%, 73.3% and 68.0% of patients receiving imeglimin 500, 1000 or 1500 mg and placebo, respectively. A small increase in gastrointestinal adverse effects (e.g. diarrhoea) occurred with the 1500 mg dose level. Hypoglycaemia was balanced among groups.

CONCLUSIONS

Imeglimin as monotherapy in Japanese patients with T2D was well tolerated and significantly improved glycaemic control with no significant increase in hypoglycaemic events versus placebo. Given the marginal increase in efficacy with the 1500 versus 1000 mg dose (along with the potential for gastrointestinal tolerability issues), a dose of 1000 mg twice-daily was selected for subsequent phase 3 studies.

Pharmacological advances in mitochondrial therapy

Mitochondria play a vital role in cellular metabolism and are central mediator of intracellular signalling, cell differentiation, morphogenesis and demise. An increasingly higher number of pathologies is linked with mitochondrial dysfunction, which can arise from either genetic defects affecting core mitochondrial components or malfunctioning pathways impairing mitochondrial homeostasis. As such, mitochondria are considered an important target in several pathologies spanning from neoplastic to neurodegenerative diseases as well as metabolic syndromes. In this review we provide an overview of the state-of-the-art in mitochondrial pharmacology, focusing on the novel compounds that have been generated in the bid to correct mitochondrial aberrations. Our work aims to serve the scientific community working on translational medical science by highlighting the most promising pharmacological approaches to target mitochondrial dysfunction in disease.

Imeglimin: Current Development and Future Potential in Type 2 Diabetes

Imeglimin is the first of the "glimins," a new class of drugs developed for the treatment of type 2 diabetes mellitus (T2DM). This review highlights its mechanism of action and its context in the field of T2DM treatment. Preclinical data in multiple rodent models have detailed significant effects on mitochondria, particularly improved mitochondrial bioenergetics. This includes changes favoring complex II and complex III metabolism, a mechanism potentially promoting increased fatty acid oxidation, leading to the decrease in hepatic lipid accumulation observed in these mice. Imeglimin was also shown to increase muscle glucose uptake and decrease hepatic glucose production, both in vitro and in vivo. Though studies have also shown imeglimin to significantly improve insulin secretion and decrease β-cell death, whether its physiologic effects are purely insulin dependent remains unclear. Early preclinical studies have shown evidence for improvements in cardiac and renal function in rats with metabolic syndrome, effects not conferred by most currently available T2DM drugs. Clinical studies of imeglimin in humans have shown increased insulin secretion, along with decreased fasting plasma glucose and glycated hemoglobin. Its observed efficacy was comparable to that of currently available agents metformin and sitagliptin and was increased when given in combination with either agent. When considered alongside its benign safety profile reported in patients with chronic kidney disease, imeglimin shows true promise to provide a novel mechanism for T2DM treatment, with potential application in a larger, more comprehensive patient population.

Riding the tiger - physiological and pathological effects of superoxide and hydrogen peroxide generated in the mitochondrial matrix

Elevated mitochondrial matrix superoxide and/or hydrogen peroxide concentrations drive a wide range of physiological responses and pathologies. Concentrations of superoxide and hydrogen peroxide in the mitochondrial matrix are set mainly by rates of production, the activities of superoxide dismutase-2 (SOD2) and peroxiredoxin-3 (PRDX3), and by diffusion of hydrogen peroxide to the cytosol. These considerations can be used to generate criteria for assessing whether changes in matrix superoxide or hydrogen peroxide are both necessary and sufficient to drive redox signaling and pathology: is a phenotype affected by suppressing superoxide and hydrogen peroxide production; by manipulating the levels of SOD2, PRDX3 or mitochondria-targeted catalase; and by adding mitochondria-targeted SOD/catalase mimetics or mitochondria-targeted antioxidants? Is the pathology associated with variants in SOD2 and PRDX3 genes? Filtering the large literature on mitochondrial redox signaling using these criteria highlights considerable evidence that mitochondrial superoxide and hydrogen peroxide drive physiological responses involved in cellular stress management, including apoptosis, autophagy, propagation of endoplasmic reticulum stress, cellular senescence, HIF1α signaling, and immune responses. They also affect cell proliferation, migration, differentiation, and the cell cycle. Filtering the huge literature on pathologies highlights strong experimental evidence that 30-40 pathologies may be driven by mitochondrial matrix superoxide or hydrogen peroxide. These can be grouped into overlapping and interacting categories: metabolic, cardiovascular, inflammatory, and neurological diseases; cancer; ischemia/reperfusion injury; aging and its diseases; external insults, and genetic diseases. Understanding the involvement of mitochondrial matrix superoxide and hydrogen peroxide concentrations in these diseases can facilitate the rational development of appropriate therapies.

Lack of Drug-Drug Interaction Between Cimetidine, a Renal Transporter Inhibitor, and Imeglimin, a Novel Oral Antidiabetic Drug, in Healthy Volunteers

BACKGROUND AND OBJECTIVE: Imeglimin is a novel oral antidiabetic drug to treat type 2 diabetes, targeting the mitochondrial bioenergetics. In vitro, imeglimin was shown to be a substrate of human multidrug and toxic extrusion transporters MATE1 and MATE2-K and organic cation transporters OCT1 and OCT2. The objective of the study was to assess the potential drug-drug interaction between imeglimin and cimetidine, a reference inhibitor of these transporters.

METHODS

A phase 1 study was carried out in 16 subjects who received a single dose of 1500 mg imeglimin alone on day 1 followed by a 6-day treatment (day 5 to day 10) with cimetidine 400 mg twice daily. On day 8, a single dose of imeglimin was co-administered with cimetidine. Blood and urine samples were collected up to 72 h after each imeglimin administration. Pharmacokinetic parameters were determined using non-compartmental methods.

RESULTS

Imeglimin maximum plasma concentration (C_max) and area under the plasma concentration-time curve (AUC) were 1.3-fold [90% CI (1.12-1.62) and (1.10-1.46) for C_max and AUC_0-last, respectively] higher when imeglimin was co-administered with cimetidine but this increase was not considered clinically relevant. This increase could be mainly explained by a reduction in renal elimination, mediated through the cimetidine inhibition of renal MATE1 transporter. Imeglimin taken alone or with cimetidine was safe and well tolerated in all subjects.

CONCLUSIONS

No clinically significant drug-drug interaction exists between imeglimin and cimetidine, a reference inhibitor of MATE1, MATE2-K, OCT1 and OCT2 transporters.

CLINICAL TRIAL REGISTRATION

EudraCT 2018-001103-36.

Potential Impact of the Multi-Target Drug Approach in the Treatment of Some Complex Diseases

It is essential to acknowledge the efforts made thus far to manage or eliminate various disease burden faced by humankind. However, the rising global trends of the so-called incurable diseases continue to put pressure on Pharma industries and other drug discovery platforms. In the past, drugs with more than one target were deemed as undesirable options with interest being on the one-drug-single target. Despite the successes of the single-target drugs, it is currently beyond doubt that these drugs have limited efficacy against complex diseases in which the pathogenesis is dependent on a set of biochemical events and several bioreceptors operating concomitantly. Different approaches have thus been proposed to come up with effective drugs to combat even the complex diseases. In the past, the focus was on producing drugs from screening plant compounds; today, we talk about combination therapy and multi-targeting drugs. The multi-target drugs have recently attracted much attention as promising tools to fight against most challenging diseases, and thus a new research focus area. This review will discuss the potential impact of multi-target drug approach on various complex diseases with focus on malaria, tuberculosis (TB), diabetes and neurodegenerative diseases as the main representatives of multifactorial diseases. We will also discuss alternative ideas to solve the current problems bearing in mind the fourth industrial revolution on drug discovery.

Microcirculation vs. Mitochondria-What to Target?

Circulatory shock is associated with marked disturbances of the macro- and microcirculation and flow heterogeneities. Furthermore, a lack of tissue adenosine trisphosphate (ATP) and mitochondrial dysfunction are directly associated with organ failure and poor patient outcome. While it remains unclear if microcirculation-targeted resuscitation strategies can even abolish shock-induced flow heterogeneity, mitochondrial dysfunction and subsequently diminished ATP production could still lead to organ dysfunction and failure even if microcirculatory function is restored or maintained. Preserved mitochondrial function is clearly associated with better patient outcome. This review elucidates the role of the microcirculation and mitochondria during circulatory shock and patient management and will give a viewpoint on the advantages and disadvantages of tailoring resuscitation to microvascular or mitochondrial targets.

Short-and long-term administration of imeglimin counters cardiorenal dysfunction in a rat model of metabolic syndrome

INTRODUCTION

Imeglimin, a glucose-lowering agent targeting mitochondrial bioenergetics, decreases reactive oxygen species (ROS) overproduction and improves glucose homeostasis. We investigated whether this is associated with protective effects on metabolic syndrome-related left ventricular (LV) and vascular dysfunctions.

METHODS

We used Zucker fa/fa rats to assess the effects on LV function, LV tissue perfusion, LV oxidative stress and vascular function induced by imeglimin administered orally for 9 or 90 days at a dose of 150 mg/kg twice daily.

RESULTS

Compared to untreated animals, 9- and 90-day imeglimin treatment decreased LV end-diastolic pressure and LV end-diastolic pressure-volume relation, increased LV tissue perfusion and decreased LV ROS production. Simultaneously, imeglimin restored acetylcholine-mediated coronary relaxation and mesenteric flow-mediated dilation. One hour after imeglimin administration, when glucose plasma levels were not yet modified, imeglimin reduced LV mitochondrial ROS production and improved LV function. Ninety-day imeglimin treatment reduced related LV and kidney fibrosis and improved kidney function.

CONCLUSION

In a rat model, mimicking Human metabolic syndrome, imeglimin immediately countered metabolic syndrome-related cardiac diastolic and vascular dysfunction by reducing oxidative stress/increased NO bioavailability and improving myocardial perfusion and after 90-day treatment myocardial and kidney structure, effects that are, at least in part, independent from glucose control.

Absence of QTc prolongation in a thorough QT study with imeglimin, a first in class oral agent for type 2 diabetes mellitus

PURPOSE

Imeglimin is the first in a new class of oral antidiabetic agents, the glimins, currently in development to improve glycemic control in patients with type 2 diabetes mellitus. A thorough QT study was conducted to establish electrophysiological effects of therapeutic and supratherapeutic doses of imeglimin on cardiac repolarization.

METHODS

In this randomized, double-blind, four-period, placebo and active controlled crossover study, healthy subjects were administered a single dose of imeglimin 2250 mg, imeglimin 6000 mg, moxifloxacin 400 mg, and placebo. 12-Lead Holter ECGs were recorded from 1 h before dosing until at least 24 h after each dose. This study was performed at a single-center inpatient clinical pharmacology unit.

RESULTS

The upper bound of the two-sided 90% confidence interval for time-matched, placebo-subtracted, baseline-adjusted QTc intervals (ΔΔQTcF) did not exceed the regulatory threshold of 10 ms in any of the imeglimin dose groups. There were no QTcF values above 500 ms nor changes from pre-dose in QTcF above 60 ms in the imeglimin groups. Imeglimin did not exert a relevant effect on heart rate and PR or QRS intervals. Assay sensitivity was demonstrated by the effect of moxifloxacin 400 mg, with a lower bound two-sided 90% confidence interval for ΔΔQTcF of 10.6 ms.

CONCLUSION

This thorough QT study demonstrated that therapeutic and supratherapeutic exposures of imeglimin did not induce a QT/QTc prolongation with a strong confidence as evidenced by the assay sensitivity.

TRIAL REGISTRATION NUMBER/DATE

NCT02924337/ October 5, 2016.

Clinical pharmacology of imeglimin for the treatment of type 2 diabetes

INTRODUCTION

With the rising prevalence of type 2 diabetes (T2D), there is a substantial interest in novel, glucose-lowering drugs that may complement existing treatment options. Imeglimin is an oral antidiabetic agent currently in clinical development.

AREAS COVERED

This review is based on a literature search using PubMed and Embase including all published manuscripts and presentations concerning imeglimin. Supplementary information was retrieved from the manufacturer's official webpage. Preclinical and clinical data are summarized with a focus on mechanisms of action as well as clinical efficacy and safety in T2D.

EXPERT OPINION

Imeglimin's mode of action seems to be improved mitochondrial function in pancreatic beta cells leading to improved insulin secretion and lowering of plasma glucose levels. In clinical trials of up to 24 weeks, imeglimin in doses of 1,000-1,500 mg twice daily conferred modest reductions in glycates hemoglobin A1c of 6-11 mmol/mol (0.5-1.0%) (placebo-adjusted) as a monotherapy and 7 mmol/mol (0.6%) as an add-on therapy to metformin or sitagliptin in patients with T2D. Reported adverse effects were mainly gastrointestinal discomfort. The position of imeglimin among other pharmacotherapies in the treatment of T2D will be determined based on future studies more clearly outlining the safety and long-term cardiovascular effects.

ABBREVIATIONS

AUC: area under the curve; BID: twice daily; DPP-4: dipeptidyl peptidase 4; GLP-1R: glucagon-like peptide-1 receptor; HbA1c: glycated hemoglobin A1c; HFHSD: high-fat high-sucrose diet; OAD: oral antidiabetic; OD: once daily; OGTT: oral glucose tolerance test; PPAR-γ: peroxisome proliferator-activated receptor gamma; PTP: permeability transition pore; SGLT-2: sodium-glucose transport protein 2; STZ: streptozotocin; T2D: type 2 diabetes.

Imeglimin Does Not Induce Clinically Relevant Pharmacokinetic Interactions When Combined with Either Metformin or Sitagliptin in Healthy Subjects

BACKGROUND AND OBJECTIVES

Imeglimin (IMEG) is the first in a novel class of oral glucose-lowering agents with a unique mechanism of action targeting mitochondrial bioenergetics. We assessed whether repeated co-administration of IMEG and either metformin (MET) or sitagliptin (SITA) would influence the pharmacokinetics of either MET or SITA in healthy Caucasian men.

METHODS

Healthy Caucasian men received either MET 850 mg twice daily with placebo (n = 16) or SITA 100 mg once daily with placebo (n = 16) on days 1-6, followed by MET 850 mg twice daily with IMEG 1500 mg twice daily or SITA 100 mg once daily with IMEG 1500 mg twice daily on days 7-12. Pharmacokinetic parameters were determined from blood and urine; levels of all compounds were evaluated using liquid chromatography with tandem mass spectrometry.

RESULTS

Systemic exposure (AUC_0-τ area under the plasma concentration-time curve over a dosing interval and maximum concentration) to MET was 14% and 10% lower, respectively, when administered with IMEG. Approximately 40% of MET was excreted unchanged in urine, decreasing to 34% when given with IMEG. The 90% confidence intervals for AUC_0-τ and maximum concentration indicated no effect of co-administration on systemic exposure to MET. Mean AUC_0-τ and maximum concentration of SITA were similar with or without IMEG. Median times to maximum concentration were 0.7 and 1.0 h and mean elimination half-lives were 8.2 and 8.7 h with and without IMEG, respectively. Systemic exposure to IMEG was similar to previous phase I studies.

CONCLUSIONS

Co-administration of IMEG with MET or SITA did not result in clinically relevant changes in systemic exposure to MET or SITA, although minor reductions in exposure (AUC_0-τ and maximum concentration) and renal elimination were noted when MET was given with IMEG vs placebo.

CLINICAL TRIAL REGISTRATION

EudraCT2009-014520-40 (MET-IMEG DDI) and EudraCT2010-022926-34 (SITA-IMEG DDI).

Molecular Mechanisms by Which Imeglimin Improves Glucose Homeostasis

Despite different classes of antidiabetic medications available for the management of patients with diabetes, efforts are underway to identify novel and safer antihyperglycemic agents with higher potency and increased tolerability. Imeglimin is a promising antidiabetic agent that has shown to have significant antihyperglycemic effects in studies, although it has not been approved yet. There is growing evidence that imeglimin improves glucose homeostasis in the diabetic milieu; however, the precise molecular mechanisms are still not elucidated. In this review, we discuss various molecular pathways by which imeglimin exerts its antihyperglycemic effects and improves glucose homeostasis in the diabetic milieu.

Single-Cell RNA Sequencing Reveals Renal Endothelium Heterogeneity and Metabolic Adaptation to Water Deprivation

BACKGROUND

Renal endothelial cells from glomerular, cortical, and medullary kidney compartments are exposed to different microenvironmental conditions and support specific kidney processes. However, the heterogeneous phenotypes of these cells remain incompletely inventoried. Osmotic homeostasis is vitally important for regulating cell volume and function, and in mammals, osmotic equilibrium is regulated through the countercurrent system in the renal medulla, where water exchange through endothelium occurs against an osmotic pressure gradient. Dehydration exposes medullary renal endothelial cells to extreme hyperosmolarity, and how these cells adapt to and survive in this hypertonic milieu is unknown.

METHODS

We inventoried renal endothelial cell heterogeneity by single-cell RNA sequencing >40,000 mouse renal endothelial cells, and studied transcriptome changes during osmotic adaptation upon water deprivation. We validated our findings by immunostaining and functionally by targeting oxidative phosphorylation in a hyperosmolarity model in vitro and in dehydrated mice in vivo.

RESULTS

We identified 24 renal endothelial cell phenotypes (of which eight were novel), highlighting extensive heterogeneity of these cells between and within the cortex, glomeruli, and medulla. In response to dehydration and hypertonicity, medullary renal endothelial cells upregulated the expression of genes involved in the hypoxia response, glycolysis, and-surprisingly-oxidative phosphorylation. Endothelial cells increased oxygen consumption when exposed to hyperosmolarity, whereas blocking oxidative phosphorylation compromised endothelial cell viability during hyperosmotic stress and impaired urine concentration during dehydration.

CONCLUSIONS

This study provides a high-resolution atlas of the renal endothelium and highlights extensive renal endothelial cell phenotypic heterogeneity, as well as a previously unrecognized role of oxidative phosphorylation in the metabolic adaptation of medullary renal endothelial cells to water deprivation.