Sex-, Species-, and Tissue-Specific Metabolism of Empagliflozin in Male Mouse Kidney Forms an Unstable Hemiacetal Metabolite (M466/2) That Degrades to 4-Hydroxycrotonaldehyde, a Reactive and Cytotoxic Species

Cancer biology in diabetes update: Focusing on antidiabetic drugs

The association of type 2 diabetes with certain cancer risk has been of great interest for years. However, the effect of diabetic medications on cancer development is not fully understood. Prospective clinical trials have not elucidated the long-term influence of hypoglycemic drugs on cancer incidence and the safety for cancer-bearing patients with diabetes, whereas numerous preclinical studies have shown that antidiabetic drugs could have an impact on carcinogenesis processes beyond the glycemic control effect. Because there is no evidence of the safety profile of antidiabetic agents on cancer biology, careful consideration would be required when prescribing any medicines to patients with diabetes and existing tumor. In this review, we discuss the potential influence of each diabetes therapy in cancer 'initiation', 'promotion' and 'progression'.

Is there any robust evidence showing that SGLT2 inhibitor predisposes to cancer?

BACKGROUND

The exact pathophysiological mechanisms of SGLT-2 inhibitors in the development, progression or treatment of malignancies are not fully understood, but multiple hypotheses have been proposed. SGLT-2 inhibitors have potential anti-proliferative roles due to several underlying pathophysiological mechanisms, such as inhibition of ATP production, activation of AMPK signalling, induction of apoptosis and ferroptosis, inhibition of glutamate dehydrogenase activity and inhibition of DNA and RNA synthesis. However, heterogeneity among tumour cells and SGLT-2 inhibitor drugs limit the generalizability of pre-clinical studies.

METHODS

This is a narrative review discussing the potential anti-cancer effects of SGLT-2 inhibitors, an oral glucose-lowering medication used in patients with type II diabetes mellitus. This review discusses underlying mechanisms, pre-clinical and clinical trial data, epidemiological data and future perspectives on the use of SGLT-2 inhibitors in cancer treatment.

RESULTS

Type II diabetes is linked to various comorbidities and malignancies, but some glucose-slowering medications may have a preventive role in cancer. The use of SGLT-2 inhibitors was associated with bladder cancer based on mice studies. However, meta-analyses showed no significant increase in overall malignancy incidence of any specific type, except for empagliflozin and bladder cancer association. SGLT-2 inhibitors can potentially reduce the heart damage caused by doxorubicin and sunitinib, while enhancing the anti-cancer effects of doxorubicin. Combining SGLT-2 inhibitors with doxorubicin may allow higher doses of chemotherapy use. Multiple ongoing clinical trials are investigating the potential therapeutic potential of SGLT-2 inhibitors in various types of cancer.

CONCLUSION

More large-scale pre-clinical and clinical studies are needed to explore their potential preventive and therapeutic roles of SGLT-2 inhibitors in cancer treatment. In this narrative review, our aim is to explore the pre-clinical and clinical data regarding the potential anti-cancer effects of SGLT-2 inhibitors including the hypothetical pathophysiological mechanisms.

SGLT-2 Inhibitors in Cancer Treatment-Mechanisms of Action and Emerging New Perspectives

A new group of antidiabetic drugs, sodium-glucose cotransporter 2 inhibitors (SGLT-2 inhibitors), have recently been shown to have anticancer effects and their expression has been confirmed in many cancer cell lines. Given the metabolic reprogramming of these cells in a glucose-based model, the ability of SGLT-2 inhibitors to block the glucose uptake by cancer cells appears to be an attractive therapeutic approach. In addition to tumour cells, SGLT-2s are only found in the proximal tubules in the kidneys. Furthermore, as numerous clinical trials have shown, the use of SGLT-2 inhibitors is well-tolerated and safe in patients with diabetes and/or heart failure. In vitro cell culture studies and preclinical in vivo studies have confirmed that SGLT-2 inhibitors exhibit antiproliferative effects on certain types of cancer. However, the mechanisms of this action remain unclear. Even in those tumour cell types in which SGLT-2 is present, there is sometimes an SGLT-2-independent mechanism of anticancer action of this group of drugs. This article presents the current state of knowledge of the potential mechanisms of the anticancer action of SGLT-2 inhibitors and their possible future application in clinical oncology.

Empagliflozin induces apoptotic-signaling pathway in embryonic vasculature: In vivo and in silico approaches via chick’s yolk sac membrane model

The present investigation was conducted to evaluate the vascular-toxicity of empagliflozin (EMP) in embryonic vasculature. Firstly, the vascular-toxicity of the drug as well as its interaction with apoptotic regulator proteins was predicted via in silico approach. In the next step, the apoptotic-signaling pathway in embryonic vasculature was evaluated using a chick’s YSM model. In silico simulation confirmed vascular-toxicity of EMP. There was also an accurate affinity between EMP, Bax and Bcl-2 (−7.9 kcal/mol). Molecular dynamics assay revealed complex stability in the human body conditions. Furthermore, EMP is suggested to alter Bcl-2 more than BAX. Morphometric quantification of the vessels showed that the apoptotic activity of EMP in embryonic vasculature was related to a marked reduction in vessel area, vessel diameter and mean capillary area. Based on the qPCR and immunohistochemistry assays, enhanced expression level of BAX and reduced expression level of Bcl-2 confirmed apoptotic responses in the vessels of the YSM. We observed that induction of an apoptotic signal can cause the embryonic defect of the vascular system following EMP treatment. The acquired data also raised suspicions that alteration in apoptotic genes and proteins in the vasculature are two critical pathways in vascular-toxicity of EMP.

Biotransformation Novel Advances - 2021 year in review

Biotransformation field is constantly evolving with new molecular structures and discoveries of metabolic pathways that impact efficacy and safety. Recent review by Kramlinger et al (2022) nicely captures the future (and the past) of highly impactful science of biotransformation (see the first article). Based on the selected articles, this review was categorized into three sections: (1) new modalities biotransformation, (2) drug discovery biotransformation, and (3) drug development biotransformation (Table 1).

Mode of Action and Human Relevance Assessment of Male CD-1 Mouse Renal Adenocarcinoma Associated With Lifetime Exposure to Empagliflozin

Inhibition of sodium-glucose cotransporter-2 (SGLT2) has been shown to be a safe and efficacious approach to support managing Type 2 diabetes. In the 2-year carcinogenicity study with the SGLT2 inhibitor empagliflozin in CD-1 mice, an increased incidence of renal tubular adenomas and carcinomas was identified in the male high-dose group but was not observed in female mice. An integrated review of available nonclinical data was conducted to establish a mode-of-action hypothesis for male mouse-specific tumorigenesis. Five key events were identified through systematic analysis to form the proposed mode-of-action: (1) Background kidney pathology in CD-1 mice sensitizes the strain to (2) pharmacology-related diuretic effects associated with SGLT2 inhibition. (3) In male mice, metabolic demand increases with the formation of a sex- and species-specific empagliflozin metabolite. These features converge to (4) deplete oxidative stress handling reserve, driving (5) constitutive cellular proliferation in male CD-1 mice. The proposed mode of action requires all five key events for empagliflozin to present a carcinogenicity risk in the CD-1 mouse. Considering that empagliflozin is not genotoxic in the standard battery of genotoxicity tests, and not all five key events are present in the context of female mice, rats or humans, nor for other osmotic diuretics or other SGLT2 inhibitors, the observed male mouse renal tumors are not considered relevant to humans.

Links between Thyroid Disorders and Glucose Homeostasis

Thyroid disorders and diabetes mellitus often coexist and are closely related. Several studies have shown a higher prevalence of thyroid disorders in patients with diabetes mellitus and vice versa. Thyroid hormone affects glucose homeostasis by impacting pancreatic β-cell development and glucose metabolism through several organs such as the liver, gastrointestinal tract, pancreas, adipose tissue, skeletal muscles, and the central nervous system. The present review discusses the effect of thyroid hormone on glucose homeostasis. We also review the relationship between thyroid disease and diabetes mellitus: type 1, type 2, and gestational diabetes, as well as guidelines for screening thyroid function with each disorder. Finally, we provide an overview of the effects of antidiabetic drugs on thyroid hormone and thyroid disorders.

The association of sodium-glucose cotransporter 2 inhibitors with cancer: An overview of quantitative systematic reviews

AIMS

To summarize reported cancer events associated with SGLT-2 inhibitors used in patients with type 2 diabetes mellitus, as well as assess the quality of included reviews.

MATERIALS AND METHODS

In May 2019, we searched PubMed, Embase and the Cochrane Library for quantitative systematic reviews assessing the safety of SGLT-2 inhibitors. Data were abstracted using a standardized form, and methodological quality was assessed using the AMSTAR 2 tool. Main outcome measures included total cancer events and specific cancers such as breast cancer, bladder cancer, gastrointestinal cancer, prostate cancer, respiratory cancer, renal cancer and skin cancer. Pooled treatment effects from included reviews were summarized for SGLT-2 inhibitors as a class and for individual SGLT-2 inhibitors commonly used worldwide (canagliflozin, dapagliflozin and empagliflozin).

RESULTS

We screened 1248 unique citations, of which eight quantitative systematic reviews meta-analysed results from studies reporting the association between an SGLT-2 inhibitor and any cancer. Only one review was rated as high quality according to AMSTAR 2 assessment. In total, data from 170 cancer-related point estimates (PE) were reported. As a class, SGLT-2 inhibitors were not associated with an increased risk of any cancer event versus placebo and active comparators. Most point estimates (7/143) were nonsignificant for individual cancers except for two associations. Empagliflozin was associated with an increased risk of bladder cancer versus placebo and active comparators in two reviews, while canagliflozin appeared protective for gastrointestinal cancer versus placebo and active comparators in one review.

CONCLUSIONS

It appears that SGLT-2 inhibitors are not associated with an increased risk of total cancer or specific cancers in patients with type 2 diabetes. However, higher quality evidence is needed to derive confident conclusions.

Cancer Biology and Prevention in Diabetes

The available evidence suggests a complex relationship between diabetes and cancer. Epidemiological data suggest a positive correlation, however, in certain types of cancer, a more complex picture emerges, such as in some site-specific cancers being specific to type I diabetes but not to type II diabetes. Reports share common and differential mechanisms which affect the relationship between diabetes and cancer. We discuss the use of antidiabetic drugs in a wide range of cancer therapy and cancer therapeutics in the development of hyperglycemia, especially antineoplastic drugs which often induce hyperglycemia by targeting insulin/IGF-1 signaling. Similarly, dipeptidyl peptidase 4 (DPP-4), a well-known target in type II diabetes mellitus, has differential effects on cancer types. Past studies suggest a protective role of DPP-4 inhibitors, but recent studies show that DPP-4 inhibition induces cancer metastasis. Moreover, molecular pathological mechanisms of cancer in diabetes are currently largely unclear. The cancer-causing mechanisms in diabetes have been shown to be complex, including excessive ROS-formation, destruction of essential biomolecules, chronic inflammation, and impaired healing phenomena, collectively leading to carcinogenesis in diabetic conditions. Diabetes-associated epithelial-to-mesenchymal transition (EMT) and endothelial-to-mesenchymal transition (EndMT) contribute to cancer-associated fibroblast (CAF) formation in tumors, allowing the epithelium and endothelium to enable tumor cell extravasation. In this review, we discuss the risk of cancer associated with anti-diabetic therapies, including DPP-4 inhibitors and SGLT2 inhibitors, and the role of catechol-o-methyltransferase (COMT), AMPK, and cell-specific glucocorticoid receptors in cancer biology. We explore possible mechanistic links between diabetes and cancer biology and discuss new therapeutic approaches.

Dysplastic urothelial changes accompany empagliflozin administration in urinary bladder of experimental diabetes

Empagliflozin (EMPA) is a promising novel antidiabetic drug; however, doubts have been raised regarding its use and the increased risk of urinary bladder carcinoma. In this study, we evaluated urothelium expression of cytokeratins (CKs) and Ki-67 proliferative activity in the urinary bladder of diabetic (DM + EMPA) and non-diabetic rats after EMPA administration. By routine histology, dysplastic changes were detected in the urothelium of diabetic as well as non-diabetic animals after EMPA administration. Moreover, the expression of CK-7 and CK-8 was significantly decreased (P < .05) while that of CK-20 as well as Ki-67 was significantly increased (P < .05) in EMPA per se and DM + EMPA urothelium groups compared to that of control and diabetics. The dysplastic changes together with the increased proliferative activity in urothelium after EMPA administration provide a cellular evidence that supports the former clinical concerns.

Microphysiological systems for ADME-related applications: current status and recommendations for system development and characterization

Over the last decade, progress has been made on the development of microphysiological systems (MPS) for absorption, distribution, metabolism, and excretion (ADME) applications. Central to this progress has been proof of concept data generated by academic and industrial institutions followed by broader characterization studies, which provide evidence for scalability and applicability to drug discovery and development. In this review, we describe some of the advances made for specific tissue MPS and outline the desired functionality for such systems, which are likely to make them applicable for practical use in the pharmaceutical industry. Single organ MPS platforms will be valuable for modelling tissue-specific functions. However, dynamic organ crosstalk, especially in the context of disease or toxicity, can only be obtained with the use of inter-linked MPS models which will enable scientists to address questions at the intersection of pharmacokinetics (PK) and efficacy, or PK and toxicity. In the future, successful application of MPS platforms that closely mimic human physiology may ultimately reduce the need for animal models to predict ADME outcomes and decrease the overall risk and cost associated with drug development.

Sodium-glucose co-transporter-2 (SGLT-2) inhibitors and cancer: A meta-analysis of randomized controlled trials

AIM

The aim of this meta-analysis of randomized trials was to assess the effects of SGLT-2i on the overall incidence of malignancies and on different types of cancer, summerizing the results of trials with a duration of at least 1 year. This was done in light of the effect of SGLT-2 inhibitors (SGLT-2is) that has been highlighted by some studies, showing an increased incidence of bladder cancer, particularly with use of empagliflozin.

MATERIALS AND METHODS

A Medline and Embase search for "Canaglifozin", "Dapaglifozin", "Empaglifozin", "Ertuglifozin", "Ipraglifozin", Tofoglifozin" or "Luseoglifozin" was performed, identifying randomized trials with a duration of more than 52 weeks up to 1 December 2018 that compared SGLT-2is with placebo or active comparators. The outcomes considered were all types of cancer and several site-specific cancers (ie, breast, pulmonary, gastrointestinal, hepatic, pancreatic, skin, prostate and bladder). Mantel-Haenszel odds ratios with 95% Confidence Intervals (MH-OR, 95% CI) were calculated for all outcomes.

RESULTS

A total of 27 trials fulfilled the inclusion criteria. Retrieved trials had enrolled 27 744 and 20 441 patients in SGLT-2 inhibitor and comparator groups, respectively. No difference was observed in the incidence of all malignancies between patients allocated to SGLT-2i and comparators (MH-OR 0.98[0.77-1.24]). The incidence of bladder cancer, and of any other type of cancer, was not significantly increased by treatment with any SGLT-2i.

CONCLUSIONS

Available data from randomized trials do not suggest a detrimental effect of SGLT-2is on the incidence of malignancies in general, or in bladder cancer in particular.

Ex vivo kidney slice preparations as a model system to study signaling cascades in kidney epithelial cells

Several model systems have been used to study signaling cascades in kidney epithelial cells, including kidney histology after systemic treatments, ex vivo isolated tubule perfusion, epithelial cell lines in culture, kidney micropuncture, and ex vivo kidney slices. We and others have found the ex vivo kidney slice method useful to study the signaling cascades involved in the regulation of kidney transport proteins. In this chapter we describe our adaptations to this classic method for the study of the regulation of kinases and endocytosis in rodent kidney epithelial cells. Briefly, slices are obtained by sectioning of freshly harvested rat or mouse kidneys using a Stadie-Riggs tissue slicer. Alternatively, a vibratome can be used to obtain slices at a more consistent and finer thickness. The harvested kidney and kidney slices are kept viable in either cell culture media or in buffers that mimic physiological conditions equilibrated with 5% CO₂ at body temperature (37°C). These buffers keep the slices viable during hours for incubations in the presence/absence of different pharmacological agents. After the incubation period the slices can be used for biochemistry experiments by preparing tissue lysates or for histological evaluation after fixation. Moreover, the fixed slices can be used to evaluate changes in subcellular trafficking of epithelial proteins or endosomes via immunolabeling followed by confocal microscopy. The resulting micrographs can then be used for systematic quantification of protein- or compartment-specific changes in subcellular localization under each condition.

Drug safety Africa: An overview of safety pharmacology & toxicology in South Africa

This meeting report is based on presentations given at the first Drug Safety Africa Meeting in Potchefstroom, South Africa from November 20-22, 2018 at the North-West University campus. There were 134 attendees (including 26 speakers and 34 students) from the pharmaceutical industry, academia, regulatory agencies as well as 6 exhibitors. These meeting proceedings are designed to inform the content that was presented in terms of Safety Pharmacology (SP) and Toxicology methods and models that are used by the pharmaceutical industry to characterize the safety profile of novel small chemical or biological molecules. The first part of this report includes an overview of the core battery studies defined by cardiovascular, central nervous system (CNS) and respiratory studies. Approaches to evaluating drug effects on the renal and gastrointestinal systems and murine phenotyping were also discussed. Subsequently, toxicological approaches were presented including standard strategies and options for early identification and characterization of risks associated with a novel therapeutic, the types of toxicology studies conducted and relevance to risk assessment supporting first-in-human (FIH) clinical trials and target organ toxicity. Biopharmaceutical development and principles of immunotoxicology were discussed as well as emerging technologies. An additional poster session was held that included 18 posters on advanced studies and topics by South African researchers, postgraduate students and postdoctoral fellows.

A complete review of empagliflozin: Most specific and potent SGLT2 inhibitor used for the treatment of type 2 diabetes mellitus

Sodium-glucose co-transporter 2 (SGLT2) inhibitors are the latest class of drugs to be introduced for the treatment of type 2 diabetes mellitus (T2DM). They reduce hyperglycemia by increasing urinary glucose excretion and exert favorable effects beyond glucose control with consistent body weight, blood pressure, and serum uric acid reductions. Empagliflozin is a potent SGLT2 inhibitor used to improve glycemic control in adults with T2DM. It has the highest SGLT2 specificity among all the clinically used or currently tested SGLT2 inhibitors. Low risk of hypoglycemia, absence of weight gain and demonstrated cardiovascular risk reduction support its consideration as a first line medication in addition to metformin for patients with T2DM and cardiovascular disease. Mostly reported adverse events are genital mycotic infections, while urinary tract infections and events linked to volume depletion are rather rare. This review covers the complete information on empagliflozin including the history of its development, synthesis, pharmacology and different methods which have been reported for its analysis.

Mechanisms of Rodent Renal Carcinogenesis Revisited

The important renal tumors that can be induced by exposure of rats to chemical carcinogens are renal tubule tumors (RTTs) derived from tubule epithelium; renal pelvic carcinoma derived from the urothelial lining of the pelvis; renal mesenchymal tumors (RMTs) derived from the interstitial connective tissue; and nephroblastoma derived from the metanephric primordia. However, almost all of our knowledge concerning mechanisms of renal carcinogenesis in the rodent pertains to the adenomas and carcinomas originating from renal tubule epithelium. Currently, nine mechanistic pathways can be identified in either the rat or mouse following chemical exposure. These include direct DNA reactivity, indirect DNA reactivity through free radical formation, multiphase bioactivation involving glutathione conjugation, mitotic disruption, sustained cell proliferation from direct cytotoxicity, sustained cell proliferation by disruption of a physiologic process (alpha 2u-globulin nephropathy), exaggerated pharmacologic response, species-dominant metabolic pathway, and chemical exacerbation of chronic progressive nephropathy. Spontaneous occurrence of RTTs in the rat will be included since one example is a confounder for interpreting kidney tumor results in chemical carcinogenicity studies in rats.

Pathogenesis of Renal Injury and Gene Expression Changes in the Male CD-1 Mouse Associated with Exposure to Empagliflozin

An increased incidence of renal tubular adenomas and carcinomas was identified in the 2-year CD-1 mouse carcinogenicity study with empagliflozin (sodium-glucose transporter 2 inhibitor) in high dose (1,000 mg/kg/day) male mice. A 13-week mouse renal investigative pathogenesis study was conducted with empagliflozin to evaluate dose dependency and temporal onset of nonneoplastic degenerative/regenerative renal tubular and molecular (genes, pathways) changes which precede neoplasia. Male and female CD-1 mice were given daily oral doses of 0, 100, 300, or 1,000 mg/kg/day (corresponding carcinogenicity study dose levels) for 1, 2, 4, 8, or 13 weeks. The maximum expected pharmacology with secondary osmotic diuresis was observed by week 1 at ≥100 mg/kg/day in both genders. Histopathologic kidney changes were first detected after 4 weeks of dosing in the male 1,000 mg/kg/day dose group, with progressive increases in the incidence and/or number of findings in this dose group so that they were more readily detected during weeks 8 and 13. Changes detected starting on week 4 consisted of minimal single-cell necrosis and minimal increases in mitotic figures. These changes persisted at an increased incidence at weeks 8 and 13 and were accompanied by minimal to mild tubular epithelial karyomegaly, minimal proximal convoluted tubular epithelial cell hyperplasia, and a corresponding increase in Ki-67-positive nuclei in epithelial cells of the proximal convoluted tubules. There were no corresponding changes in serum chemistry or urinalysis parameters indicative of any physiologically meaningful effect on renal function and thus these findings were not considered to be adverse. Similar changes were not identified in lower-dose groups in males nor were they present in females of any dose group. RNA-sequencing analysis revealed male mouse-specific changes in kidney over 13 weeks of dosing at 1,000 mg/kg/day. Treatment-related changes included genes and pathways related to p53-regulated cell cycle and proliferation, transforming growth factor β, oxidative stress, and renal injury and the number of genes with significant expression change dramatically increased at week 13. These treatment-related changes in genes and pathways were predominant in high-dose males and complemented the observed temporal renal tubular changes. Overall, these mouse investigative study results support the role of early empagliflozin-related degenerative/regenerative changes only observed in high-dose male CD-1 mice as a key contributing feature to a nongenotoxic mode of renal tumor pathogenesis.

Organic anion transporter OAT3 enhances the glucosuric effect of the SGLT2 inhibitor empagliflozin

The sodium-glucose cotransporter SGLT2 inhibitor empagliflozin (plasma protein binding ~88%) may reach its target in the brush border of the early proximal tubule by glomerular filtration and tubular secretion. Here we determined whether empagliflozin is secreted by renal tubules in mice and whether genetic knockout of the basolateral organic anion transporter 3 ( Oat3-/-) affects its tubular secretion or glucosuric effect. Renal clearance studies in wild-type (WT) mice showed that tubular secretion accounted for 50-70% of empagliflozin urinary excretion. Immunostaining indicated that SGLT2 and OAT3 localization partially overlapped in proximal tubule S1 and S2 segments. Glucosuria in metabolic cage studies was reduced in Oat3-/- vs. WT mice for acute empagliflozin doses of 1, 3, and 10 mg/kg, whereas 30 mg/kg induced similar maximal glucosuria in both genotypes. Chronic application of empagliflozin (~25 mg·kg^-1 ·day^-1) in Oat3-/- mice was associated with lower urinary glucose-to-creatinine ratios despite maintaining slightly higher blood glucose levels than WT. On a whole kidney level, renal secretion of empagliflozin was largely unchanged in Oat3-/- mice. However, the absence of OAT3 attenuated the influence of empagliflozin on fractional glucose excretion; higher levels of plasma or filtered empagliflozin were needed to induce similar increases in fractional renal glucose excretion. We conclude that empagliflozin is excreted into the urine to similar extent by glomerular filtration and tubular secretion. The latter can occur largely independent of OAT3. However, OAT3 increases the glucosuric effect of empagliflozin, which may relate to the partial overlap of its localization with SGLT2 and thus OAT3-mediated tubular secretion of empagliflozin in the early proximal tubule.

A Predominant Oxidative Renal Metabolite of Empagliflozin in Male Mice Is Cytotoxic in Mouse Renal Tubular Cells but not Genotoxic

In a previously reported CD-1 mouse 2-year carcinogenicity study with the sodium glucose cotransporter-2 inhibitor empagliflozin, an increased incidence of renal tubular adenomas and carcinomas was identified only in the male high-dose group. Follow-up investigative studies have shown that the renal tumors in male high-dose mice were preceded by a number of renal degenerative/regenerative findings. Prior cross-species in vitro metabolism studies using microsomes identified an oxidative metabolite (M466/2) predominantly formed in the male mouse kidney and which spontaneously degrades to a metabolite (M380/1) and reactive 4-OH crotonaldehyde (CTA). In order to further evaluate potential modes of action for empagliflozin-associated male mouse renal tumors, we report here a series of in vitro investigative toxicology studies conducted to evaluate the cytotoxic and genotoxic potential of empagliflozin and M466/2. To assess the cytotoxic potential of empagliflozin and M466/2, a primary mouse renal tubular epithelial (mRTE) cell model was used. In mRTE cells, M466/2-derived in vitro 4-OH CTA exposure was cytotoxic, while empagliflozin was not cytotoxic or mitogenic. Empagliflozin and M466/2 were not genotoxic, supporting an indirect mode of action for empagliflozin-associated male mouse renal tumorigenesis. In conclusion, these in vitro data show that M466/2-derived 4-OH CTA exposure is associated with cytotoxicity in renal tubule cells and may be involved in promoting compound-related in vivo renal metabolic stress and chronic low-level renal injury, in turn supporting a nongenotoxic mode of tumor pathogenesis specific to the male mouse.

SGLT2 inhibitors and risk of cancer in type 2 diabetes: a systematic review and meta-analysis of randomised controlled trials

AIMS/HYPOTHESIS

The association between sodium-glucose cotransporter 2 (SGLT2) inhibitors and the risk of cancer in individuals with type 2 diabetes remains uncertain. This study aimed to evaluate the risk of cancer associated with SGLT2 inhibitor treatment of type 2 diabetes.

METHODS

We systematically searched PubMed, EMBASE, Cochrane Central Register of Controlled Trials and ClinicalTrials.gov from inception to 15 February 2017 to identify eligible randomised controlled trials (RCTs) that report cancer events in individuals with type 2 diabetes treated with SGLT2 inhibitors for at least 24 weeks. We performed pairwise and network meta-analyses as well as a cumulative meta-analysis to calculate ORs and 95% CIs.

RESULTS

In total, 580 incidences of cancer among 34,569 individuals were identified from 46 independent RCTs with a mean trial duration of 61 weeks. When compared with comparators (placebo or other active glucose-lowering treatments), SGLT2 inhibitors were not significantly associated with an increased risk of overall cancer (OR 1.14 [95% CI 0.96, 1.36]). For pre-specified cancer types, the risk of bladder cancer might be increased with SGLT2 inhibitors (OR 3.87 [95% CI 1.48, 10.08]), especially empagliflozin (OR 4.49 [95% CI 1.21, 16.73]). Interestingly, canagliflozin might be protective against gastrointestinal cancers (OR 0.15 [95% CI 0.04, 0.60]).

CONCLUSIONS/INTERPRETATION

Current evidence from short-term RCTs did not indicate a significantly increased risk of overall cancer among individuals with type 2 diabetes using SGLT2 inhibitors. Given the short-term trial durations and uncertainty of evidence, future long-term prospective studies and post-marketing surveillance studies are warranted.

Diabetes drugs and the incidence of solid cancers: a survey of the current evidence

INTRODUCTION

The evaluation of the relationship between the use of antidiabetic drug and the occurrence of cancer is extremely challenging, both from the clinical and pharmacoepidemiological standpoint. This narrative review described the current evidence supporting a relationship between the use of antidiabetic drugs and the incidence of solid cancers. Areas covered: Data from pharmacoepidemiological studies on cancer incidence were presented for the main antidiabetic drugs and drug classes, including human insulin and insulin analogues, metformin, sulfonylureas, glinides, alpha-glucosidase inhibitors, thiazolidinediones, incretin mimetics, and sodium glucose co-transporter 2 inhibitors. The relationship between the use of antidiabetics and the incidence of solid cancer was described in strata by any cancer and by organ-specific cancer and by drug and by drug classes. Information supporting biological evidence and putative mechanisms were also provided. Expert opinion: The history of exploration of the relationship between antidiabetic drugs and the risk of solid cancers has showed several issues. Unrecognized biases and misinterpretations of study results have had important consequences that delayed the identification of actual risk and benefits of the use of antidiabetic drugs associated with cancer occurrence or progression. The lesson learned from the past should address the future research in this area, since in the majority of cases findings are controversial and confirmatory studies are warranted.

Empagliflozin: a new strategy for nephroprotection in diabetes

Empagliflozin, an inhibitor of sodiumglucose symporter type 2 (SGLT2), is a new class of antidiabetic agents with numerous pleiotropic effects. The review summarises data on the influence of empagliflozin on the structural and functional changes in the kidneys of the models of diabetes mellitus (DM) and of patients with DM. A literature search was conducted using the databases of Medline/PubMed, Scopus, Web of Science, ClinicalTrials.gov and eLibrary. The experimental results showed a decrease in the blood glucose level, blood pressure, glomerular hyperfiltration and overexpression of proinflammatory and fibrogenic factors in the kidneys under the influence of empagliflozin. Most clinical studies have demonstrated the albuminuria-lowering effect of empagliflozin in patients with type 2 DM. The EMPA-REG OUTCOME study has demonstrated slowing of the chronic kidney disease progression, decrease in the incidence of end-stage renal failure and death from renal causes in patients with type 2 DM undergoing the empagliflozin treatment compared with those receiving placebo. The mechanisms of the nephroprotective effect of empagliflozin included systemic and renal effects. The decrease in hyperglycaemia, blood pressure and body weight; reduction in glomerular hyperfiltration; enhancement of sodium excretion and suppression of inflammatory and fibrogenic signalling pathways in the kidneys may help slow the development of diabetic kidney damage under the influence of empagliflozin. The possibility of extrapolating the confirmed properties of empagliflozin to other SGLT2 inhibitors needs further investigation.

Does Gender Influence the Cardiovascular Benefits Observed with Sodium Glucose Co-Transporter-2 (SGLT-2) Inhibitors? A Meta-Regression Analysis

Introduction

Although a large recent trial had shown improved cardiovascular outcomes of diabetic patients on sodium glucose co-transporter-2 (SGLT-2) inhibitors, the influence of gender differences on such outcomes is not known. Thus, we aimed to assess the impact of gender on such outcomes in the patients with type 2 diabetes mellitus receiving SGLT-2 inhibitors.

Methods

A search of electronic databases was conducted for all randomized trials comparing SGLT-2 inhibitors with placebo in patients with diabetes mellitus. Primary outcomes were all-cause mortality and cardiovascular mortality. Random effects meta-regression was conducted using the percentage of women included in the SGLT-2 inhibitor arm of each trial with a P value of <0.1 for statistical significance.

Results

A total of 22,256 patients from 26 trials were included. The overall odds ratio (OR) of all-cause mortality [OR = 0.72, 95% confidence interval (CI) 0.60–0.86, P < 0.001, I² = 0%], and cardiovascular mortality (OR = 0.67, 95% CI 0.53–0.84, P = 0.001, I² = 23%) were lower with SGLT-2 inhibitors. Meta-regression suggested a possible incremental increase in the OR for all-cause mortality and cardiovascular mortality as the percentage of women in the SGLT-2 inhibitor arm increased (P = 0.07 and 0.08, respectively).

Conclusion

Gender might influence the cardiovascular benefits observed with SGLT-2 inhibitors in patients with type 2 diabetes mellitus.

Electronic supplementary material

The online version of this article (doi:10.1007/s40119-016-0075-1) contains supplementary material, which is available to authorized users.

Evaluation of the pharmacokinetics, pharmacodynamics and clinical efficacy of empagliflozin for the treatment of type 2 diabetes

INTRODUCTION

Sodium-glucose co-transporter 2 (SGLT2) inhibitors are the latest class of drugs to be introduced for the treatment of type 2 diabetes mellitus. These drugs improve glycemic control by increasing urinary glucose excretion and exert additional benefits of weight loss and blood pressure reductions. Areas covered: This review outlines the background to SGLT2 inhibitors and provides details on the pharmacokinetics, pharmacodynamics and clinical efficacy of empagliflozin and discusses the cardiovascular outcome trial. Expert opinion: Empagliflozin was the first from a new group of antidiabetic drugs to show benefits in a cardiovascular outcome trial. There were significant reductions in cardiovascular and all-cause mortality and empagliflozin treatment reduced hospitalizations for heart failure and reduced the progression of diabetic nephropathy. These benefits, which occurred at a very early stage during the study, may be related to a reduction in circulating volume or changes in metabolic fuel utilization in the heart and kidneys. Whether these effects are shared by other SGLT2 inhibitors is not yet known, but there may be differences between drugs related to selectivity for inhibition of SGLT2 compared to SGLT1 or other pharmacological effects. Currently the outcome evidence is only available to support the use of empagliflozin in this drug class.

Assessing Bladder Cancer Risk in Type 2 Diabetes Clinical Trials: the Dapagliflozin Drug Development Program as a 'Case Study'

INTRODUCTION

Dapagliflozin, a sodium-glucose co-transporter 2 inhibitor, decreases plasma glucose levels by suppressing renal glucose reabsorption and increasing urinary glucose excretion. Previously published pre-clinical data suggest that dapagliflozin lacks carcinogenic potential. This article reviews data on bladder cancer with dapagliflozin to illustrate the challenges in assessing bladder cancer in drug development programs in patients with type 2 diabetes mellitus (T2DM).

METHODS

Clinical cases of bladder cancer were analyzed in a pooled population of >9000 patients in 21 phase 2b/3 dapagliflozin clinical trials of up to 208 weeks' duration.

RESULTS

In the 21-study pool, demographic and baseline characteristics were generally consistent between dapagliflozin and comparator groups. The overall incidence of malignancies was also balanced between the treatment groups, with an incidence rate ratio (IRR) of 1.035 [95% confidence interval (CI): 0.724, 1.481]. Nine of 5936 dapagliflozin-treated patients and 1 of 3403 comparator-treated patients reported bladder cancer, with an IRR of 5.168 (95% CI: 0.677, 233.55). All of these patients had clinical attributes typical of bladder cancer in the general population (≥60-year-old males; 8 of the 10 patients were current/former smokers). All cases of bladder cancer were reported within 2 years of starting study treatment. There was an absence of detailed workup of hematuria prior to randomization, and no hematuria workup data were collected proactively in the dapagliflozin trials, which is typical of clinical practice. Failure to exclude bladder cancer prior to randomization increases the chance of recruiting patients with pre-existing bladder cancer in clinical trials and may delay the final diagnosis. Of the nine dapagliflozin-treated patients with bladder cancer, eight had microscopic hematuria prior to start of treatment or within 6 months of initiating study treatment.

CONCLUSION

The assessment of bladder cancer data illustrates the challenges of characterizing cancer risk in T2DM drug development programs. The totality of evidence to date does not suggest a causal relationship between dapagliflozin and bladder cancer.

FUNDING

AstraZeneca.