Role of Glycosuria in SGLT2 Inhibitor-Induced Cardiorenal Protection: A Mechanistic Analysis of the CREDENCE Trial

SGLT2 inhibitors have been shown to provide pronounced reductions in cardiorenal outcomes, including cardiovascular death, heart failure, and renal failure. The mechanisms underlying these benefits remain uncertain. We hypothesized that the effects could be attributed to the elevated glycosuria induced by these drugs. Urine concentrations of glucose, creatinine, and ketones were measured at baseline and after 1 year of treatment with either placebo or canagliflozin 100 mg/day, in approximately 2,600 individuals from the Canagliflozin and Renal Events in Diabetes with Established Nephropathy Clinical Evaluation (CREDENCE) trial (enrolling patients with type 2 diabetes, chronic kidney disease (CKD), and albuminuria). Associations between glycosuria and the primary composite end point from CREDENCE, and secondary outcomes were assessed using Cox proportional hazards models. Canagliflozin treatment increased fractional urinary glucose excretion (± SD) from 3 ± 9% at baseline to 30 ± 26% at year 1 (vs. 5 ± 19% with placebo; P < 0.001). Patients in the canagliflozin arm and in the top quartile of urine glucose to creatinine ratio at year 1 were significantly protected for the primary end point (hazard ratio [HR] 0.42; 95% CI 0.30-0.61); similar results were seen for cases of hospitalized heart failure (HR 0.45; 95% CI 0.27-0.73) and all-cause death (HR 0.56; 95% CI 0.39-0.80). These associations persisted when adjustments were made for multiple conventional risk factors. Among patients with type 2 diabetes and CKD treated with canagliflozin, individuals with the highest glycosuria levels had the strongest protection against multiple cardiorenal outcomes.

ARTICLE HIGHLIGHTS

A long-acting GDF15 analog causes robust, sustained weight loss and reduction of food intake in an obese nonhuman primate model

Growth Differentiation Factor-15 (GDF15) is a circulating polypeptide linked to cellular stress and metabolic adaptation. GDF15's half-life is ~3 h and activates the glial cell line-derived neurotrophic factor family receptor alpha-like (GFRAL) receptor expressed in the area postrema. To characterize sustained GFRAL agonism on food intake (FI) and body weight (BW), we tested a half-life extended analog of GDF15 (Compound H [CpdH]) suitable for reduced dosing frequency in obese cynomolgus monkeys. Animals were chronically treated once weekly (q.w.) with CpdH or long-acting GLP-1 analog dulaglutide. Mechanism-based longitudinal exposure-response modeling characterized effects of CpdH and dulaglutide on FI and BW. The novel model accounts for both acute, exposure-dependent effects reducing FI and compensatory changes in energy expenditure (EE) and FI occurring over time with weight loss. CpdH had linear, dose-proportional pharmacokinetics (terminal half-life ~8 days) and treatment caused exposure-dependent reductions in FI and BW. The 1.6 mg/kg CpdH reduced mean FI by 57.5% at 1 week and sustained FI reductions of 31.5% from weeks 9-12, resulting in peak reduction in BW of 16 ± 5%. Dulaglutide had more modest effects on FI and peak BW loss was 3.8 ± 4.0%. Longitudinal modeling of both the FI and BW profiles suggested reductions in BW observed with both CpdH and dulaglutide were fully explained by exposure-dependent reductions in FI without increase in EE. Upon verification of the pharmacokinetic/pharmacodynamic relationship established in monkeys and humans for dulaglutide, we predicted that CpdH could reach double digit BW loss in humans. In summary, a long-acting GDF15 analog led to sustained reductions in FI in overweight monkeys and holds potential for effective clinical obesity pharmacotherapy.

Validation of a diet-induced Macaca fascicularis model of non-alcoholic steatohepatitis with dietary and pioglitazone interventions

AIM

To develop an obese, insulin-resistant cynomolgus monkey model of non-alcoholic steatohepatitis (NASH) with fibrosis with a high fat/high cholesterol (HFHC) diet (with or without high fructose) and test its responsiveness to caloric restriction or pioglitazone.

METHODS

First, two groups of monkeys (n = 24/group) with histologically proven NASH and fibrosis were fed the HFHC diet for 17 weeks. The treatment group was subjected to a 40% caloric restriction (CR) and had their diet switched from the HFHC diet to a chow diet (DSCR). Paired liver biopsies were taken before and 17 weeks after DSCR. Subsets of monkeys (nine/group) had whole liver fat content assessed by MRI. Next, two groups of monkeys with histologically proven NASH and fibrosis were treated with vehicle (n = 9) or pioglitazone (n = 20) over 24 weeks.

RESULTS

The HFHC and DSCR groups lost 0.9% and 11.4% of body weight, respectively. After 17 weeks, non-alcoholic fatty liver disease activity score (NAS) improvement was observed in 66.7% of the DSCR group versus 12.5% of the HFHC group (P < .001). Hepatic fat was reduced to 5.2% in the DSCR group versus 23.0% in the HFHC group (P = .0001). After 24 weeks, NAS improvement was seen in 30% of the pioglitazone group versus 0% of the vehicle group (P = .08).

CONCLUSIONS

Both weight loss induced by DSCR and treatment with pioglitazone improve the histological features of NASH in a diet-induced cynomolgus monkey model. This model provides a translational preclinical model for testing novel NASH therapies.

Intrahepatic fat, irrespective of ethnicity, is associated with reduced endogenous insulin clearance and hepatic insulin resistance in obese youths: A cross-sectional and longitudinal study from the Yale Pediatric NAFLD cohort

AIM

To evaluate whether intrahepatic fat accumulation contributes to impaired insulin clearance and hepatic insulin resistance across different ethnic groups.

METHODS

The intrahepatic fat content (HFF%) was quantified by magnetic resonance imaging in a multi-ethnic cohort of 632 obese youths aged 7-18 years at baseline and after a 2-year follow-up. Insulin secretion rate (ISR), endogenous insulin clearance (EIC) and hepatic insulin resistance index (HIRI) were estimated by modelling glucose, insulin and C-peptide data during 3-hour, 9-point oral glucose tolerance tests.

RESULTS

African American youths exhibited the lowest HFF% and a prevalence of non-alcoholic fatty liver disease (NAFLD) less than half of that shown by Caucasians and Hispanics. Furthermore, African Americans had lower EIC and glucose-stimulated ISR, despite similar HIRI and plasma insulin levels, compared with Caucasians and Hispanics. EIC and HIRI were markedly reduced in individuals with NAFLD and declined across group-specific HFF% tertiles in all ethnic groups. Consistently, the HFF% correlated with EIC and HIRI, irrespective of the ethnic background, after adjustment for age, sex, ethnicity, adiposity, waist-hip ratio, pubertal status and plasma glucose levels. An increased HFF% at follow-up was associated with decreased EIC and increased HIRI across all groups.

CONCLUSIONS

Intrahepatic lipid accumulation is associated with reduced insulin clearance and hepatic insulin sensitivity in obese youths, irrespective of their ethnic background.

Lower Insulin Clearance Parallels a Reduced Insulin Sensitivity in Obese Youths and Is Associated With a Decline in β-Cell Function Over Time

We examined the relationship between insulin clearance, insulin sensitivity, and β-cell function and the longitudinal effect of insulin clearance on β-cell function in lean and obese insulin-sensitive and insulin-resistant adolescents. A hyperinsulinemic-euglycemic and a hyperglycemic clamp were performed in 110 youths to quantify hepatic and peripheral clearance, insulin sensitivity, and β-cell function (disposition index, DI_h-clamp). Participants underwent an oral glucose tolerance test at baseline and after 2 years to assess glucose tolerance and oral β-cell function (oDI_cpep) and were sorted into four groups (lean and obese normal glucose tolerance, insulin sensitive, insulin resistant, and impaired glucose tolerance). Insulin sensitivity was defined based on the median of insulin stimulated glucose disposal (M) measured during the hyperinsulinemic-euglycemic clamp. Lean and obese insulin-sensitive participants did not differ with respect to hepatic and peripheral clearance or for insulin sensitivity. Insulin sensitivity was linearly correlated with whole-body insulin clearance. Hepatic insulin extraction at baseline acted as an independent determinant of β-cell function at follow-up. The decline in insulin sensitivity, even in the absence of an impairment of glucose tolerance, is associated with lowering of hepatic insulin clearance in obese youth, which in turn may contribute to the decline in β-cell function over time.

Effect of canagliflozin treatment on hepatic triglyceride content and glucose metabolism in patients with type 2 diabetes

AIM

To evaluate the impact of the sodium glucose co-transporter 2 inhibitor canagliflozin on intrahepatic triglyceride (IHTG) accumulation and its relationship to changes in body weight and glucose metabolism.

MATERIALS AND METHODS

In this double-blind, parallel-group, placebo-controlled, 24-week trial subjects with inadequately controlled type 2 diabetes mellitus (T2DM; HbA1c = 7.7% ± 0.7%) from two centres were randomly assigned (1:1) to canagliflozin 300 mg or placebo. We measured IHTG by proton-magnetic resonance spectroscopy (primary outcome), hepatic/muscle/adipose tissue insulin sensitivity during a 2-step euglycaemic insulin clamp, and beta-cell function during a mixed meal tolerance test. Analyses were per protocol.

RESULTS

Between 8 September 2014-13 June 2016, 56 patients were enrolled. Canagliflozin reduced HbA1c (placebo-subtracted change: -0.71% [-1.08; -0.33]) and body weight (-3.4% [-5.4; -1.4]; both P ≤ 0.001). A numerically larger absolute decrease in IHTG occurred with canagliflozin (-4.6% [-6.4; -2.7]) versus placebo (-2.4% [-4.2; -0.6]; P = 0.09). In patients with non-alcoholic fatty liver disease (n = 37), the decrease in IHTG was -6.9% (-9.5; -4.2) versus -3.8% (-6.3; -1.3; P = 0.05), and strongly correlated with the magnitude of weight loss (r = 0.69, P < 0.001). Body weight loss ≥5% with a ≥30% relative reduction in IHTG occurred more often with canagliflozin (38% vs. 7%, P = 0.009). Hepatic insulin sensitivity improved with canagliflozin (P < 0.01), but not muscle or adipose tissue insulin sensitivity. Beta-cell glucose sensitivity, insulin clearance, and disposition index improved more with canagliflozin (P < 0.05).

CONCLUSIONS

Canagliflozin improves hepatic insulin sensitivity and insulin secretion and clearance in patients with T2DM. IHTG decreases in proportion to the magnitude of body weight loss, which tended to be greater and occur more often with canagliflozin.

Quantitative path to deep phenotyping: Possible importance of reduced hepatic insulin degradation to type 2 diabetes mellitus pathogenesis

Diabetes is often thought of as one of two diseases: Type 1 diabetes (T1D), which is caused by immunological destruction of the beta-cells, and Type 2 diabetes (T2D), which is due to a combination of insulin resistance and relative failure of the beta-cells to compensate for the resistance. It is becoming clear, however, that even within these two definitions there may be considerable heterogeneity (1). There are several approaches to examine heterogeneity of T2D. Among these approaches are the use of biomarkers to categorize the disease, or the examination of variants in the genome. A third approach – the one we have been using in our laboratory – is to identify specific phenotypes which may contribute to failure to regulate the glucose level. We have identified a small group of such phenotypes which can be distinguished and measured using clinical protocols and/or mathematical modeling.

Pharmacokinetics and pharmacodynamics of canagliflozin in pediatric patients with type 2 diabetes

OBJECTIVE

Canagliflozin, a sodium glucose cotransporter 2 inhibitor approved for the treatment of adults with type 2 diabetes (T2D), increases urinary glucose excretion (UGE) and lowers plasma glucose (PG) levels by reducing the renal threshold for glucose (RT_G ). This study assessed the pharmacokinetics (PK) and pharmacodynamics (PD) of canagliflozin in pediatric T2D patients.

METHODS

Patients, aged 10 to 17 years with mean weight 107.2 kg and body mass index 38.2 kg/m² , underwent PK and PD assessments after receiving a single daily dose of canagliflozin 100 mg (n = 8) or 300 mg (n = 9) for 14 days. Data are presented as mean (SD).

RESULTS

There were dose-dependent increases in the PK of canagliflozin 100 and 300 mg, with maximum plasma concentrations and areas under plasma concentration curves that were similar to the corresponding values in adults. Mean 24-hour RT_G fell to 84.6 (13.8) mg/dL with canagliflozin 100 mg and to 69.1 (9.6) mg/dL with canagliflozin 300 mg; also consistent with reductions in RT_G in adults. Mean 24-hour UGE increased from 5.3 (10.5) g at baseline to 74.1 (37.4) g with canagliflozin 100 mg and from 0.1 (0.04) g to 68.6 (26.5) g with canagliflozin 300 mg. Both doses were well tolerated and the tablets had acceptable taste, smell, and swallowability.

CONCLUSIONS

In pediatric T2D patients, canagliflozin 100 and 300 mg had PK and PD characteristics similar to those in adults with T2D, which is likely due to the relative maturity and increased body weight of youth affected with this disorder.

Intra- and inter-subject variability for increases in serum ketone bodies in patients with type 2 diabetes treated with the sodium glucose co-transporter 2 inhibitor canagliflozin

Sodium glucose co-transporter 2 (SGLT2) inhibitors have been associated with increased serum ketone body levels in patients with type 2 diabetes mellitus (T2DM). In the present analysis we evaluated serum ketone body levels and variability in 1278 Japanese patients with T2DM treated with canagliflozin 100 or 200 mg. Similar mean increases in ketone body concentrations of ~2-fold were seen with both canagliflozin doses. The median (interquartile range) percent change from baseline was 62% (0;180) for acetoacetate and 78% (2;236) for β-hydroxybutyrate. Approximately two-thirds of the variability in each ketone measure was attributed to intra-subject variability. Intra-subject variability was higher for serum ketones than other metabolites. Patients in the lowest response tertile exhibited no increase in ketones. Those in the highest response tertile tended to be male and have higher fasting plasma glucose levels, lower insulin levels, and longer T2DM duration at baseline. Moreover, changes in serum ketones were not fully explained by changes in plasma fatty acids, suggesting downstream effects of SGLT2 inhibition on hepatic metabolism that favour ketogenesis. In summary, increases in serum ketone bodies with canagliflozin were greater and more variable than changes in other metabolic measures in Japanese patients with T2DM.

Potent Sodium/Glucose Cotransporter SGLT1/2 Dual Inhibition Improves Glycemic Control Without Marked Gastrointestinal Adaptation or Colonic Microbiota Changes in Rodents

The sodium/glucose cotransporters (SGLT1 and SGLT2) transport glucose across the intestinal brush border and kidney tubule. Dual SGLT1/2 inhibition could reduce hyperglycemia more than SGLT2-selective inhibition in patients with type 2 diabetes. However, questions remain about altered gastrointestinal (GI) luminal glucose and tolerability, and this was evaluated in slc5a1^-/- mice or with a potent dual inhibitor (compound 8; SGLT1 K_i = 1.5 ± 0.5 nM 100-fold greater potency than phlorizin; SGLT2 K_i = 0.4 ± 0.2 nM). ¹³C₆-glucose uptake was quantified in slc5a1^-/- mice and in isolated rat jejunum. Urinary glucose excretion (UGE), blood glucose (Sprague-Dawley rats), glucagon-like peptide 1 (GLP-1), and hemoglobin A1c (HbA1c) levels (Zucker diabetic fatty rats) were measured. Intestinal adaptation and rRNA gene sequencing was analyzed in C57Bl/6 mice. The blood ¹³C₆-glucose area under the curve (AUC) was reduced in the absence of SGLT1 by 75% (245 ± 6 vs. 64 ± 6 mg/dl⋅h in wild-type vs. slc5a1^-/- mice) and compound 8 inhibited its transport up to 50% in isolated rat jejunum. Compound 8 reduced glucose excursion more than SGLT2-selective inhibition (e.g., AUC = 129 ± 3 vs. 249 ± 5 mg/dl⋅h for 1 mg/kg compound 8 vs. dapagliflozin) with similar UGE but a lower renal glucose excretion threshold. In Zucker diabetic fatty rats, compound 8 decreased HbA1c and increased total GLP-1 without changes in jejunum SGLT1 expression, mucosal weight, or villus length. Overall, compound 8 (1 mg/kg for 6 days) did not increase cecal glucose concentrations or bacterial diversity in C57BL/6 mice. In conclusion, potent dual SGLT1/2 inhibition lowers blood glucose by reducing intestinal glucose absorption and the renal glucose threshold but minimally impacts the intestinal mucosa or luminal microbiota in chow-fed rodents.

Dynamic population pharmacokinetic-pharmacodynamic modelling and simulation supports similar efficacy in glycosylated haemoglobin response with once or twice-daily dosing of canagliflozin

AIM

Canagliflozin is an SGLT2 inhibitor approved for the treatment of type-2 diabetes. A dynamic population pharmacokinetic-pharmacodynamic (PK/PD) model relating 24-h canagliflozin exposure profiles to effects on glycosylated haemoglobin was developed to compare the efficacy of once-daily and twice-daily dosing.

METHODS

Data from two clinical studies, one with once-daily, and the other with twice-daily dosing of canagliflozin as add-on to metformin were used (n = 1347). An established population PK model was used to predict full 24-h profiles from measured trough concentrations and/or baseline covariates. The dynamic PK/PD model incorporated an E_max relationship between 24-h canagliflozin exposure and HbA1c-lowering with baseline HbA1c affecting the efficacy.

RESULTS

Internal and external model validation demonstrated that the model adequately predicted HbA1c-lowering for canagliflozin once-daily and twice-daily dosing regimens. The differences in HbA1c reduction between the twice-daily and daily mean profiles were minimal (at most 0.023% for 100 mg total daily dose [TDD] and 0.011% for 300 mg TDD, up to week 26, increasing with time and decreasing with TDD) and not considered clinically meaningful.

CONCLUSIONS

Simulations using this model demonstrated the absence of clinically meaningful between-regimen differences in efficacy, supported the regulatory approval of a canagliflozin-metformin immediate release fixed-dose combination tablet and alleviated the need for an additional clinical study.

How Strongly Does Appetite Counter Weight Loss? Quantification of the Feedback Control of Human Energy Intake

OBJECTIVE

To quantify the feedback control of energy intake in response to long-term covert manipulation of energy balance in free-living humans.

METHODS

A validated mathematical method was used to calculate energy intake changes during a 52-week placebo-controlled trial in 153 patients treated with canagliflozin, a sodium glucose co-transporter inhibitor that increases urinary glucose excretion, thereby resulting in weight loss without patients being directly aware of the energy deficit. The relationship between the body weight time course and the calculated energy intake changes was analyzed using principles from engineering control theory.

RESULTS

It was discovered that weight loss leads to a proportional increase in appetite resulting in eating above baseline by ∼100 kcal/day per kilogram of lost weight-an amount more than threefold larger than the corresponding energy expenditure adaptations.

CONCLUSIONS

While energy expenditure adaptations have often been considered the main reason for slowing of weight loss and subsequent regain, feedback control of energy intake plays an even larger role and helps explain why long-term maintenance of a reduced body weight is so difficult.

Standardized Mixed-Meal Tolerance and Arginine Stimulation Tests Provide Reproducible and Complementary Measures of β-Cell Function: Results From the Foundation for the National Institutes of Health Biomarkers Consortium Investigative Series

OBJECTIVE

Standardized, reproducible, and feasible quantification of β-cell function (BCF) is necessary for the evaluation of interventions to improve insulin secretion and important for comparison across studies. We therefore characterized the responses to, and reproducibility of, standardized methods of in vivo BCF across different glucose tolerance states.

RESEARCH DESIGN AND METHODS

Participants classified as having normal glucose tolerance (NGT; n = 23), prediabetes (PDM; n = 17), and type 2 diabetes mellitus (T2DM; n = 22) underwent two standardized mixed-meal tolerance tests (MMTT) and two standardized arginine stimulation tests (AST) in a test-retest paradigm and one frequently sampled intravenous glucose tolerance test (FSIGT).

RESULTS

From the MMTT, insulin secretion in T2DM was >86% lower compared with NGT or PDM (P < 0.001). Insulin sensitivity (Si) decreased from NGT to PDM (∼50%) to T2DM (93% lower [P < 0.001]). In the AST, insulin secretory response to arginine at basal glucose and during hyperglycemia was lower in T2DM compared with NGT and PDM (>58%; all P < 0.001). FSIGT showed decreases in both insulin secretion and Si across populations (P < 0.001), although Si did not differ significantly between PDM and T2DM populations. Reproducibility was generally good for the MMTT, with intraclass correlation coefficients (ICCs) ranging from ∼0.3 to ∼0.8 depending on population and variable. Reproducibility for the AST was very good, with ICC values >0.8 across all variables and populations.

CONCLUSIONS

Standardized MMTT and AST provide reproducible and complementary measures of BCF with characteristics favorable for longitudinal interventional trials use.

Apparent subadditivity of the efficacy of initial combination treatments for type 2 diabetes is largely explained by the impact of baseline HbA1c on efficacy

AIM

To explain the subadditive efficacy typically observed with initial combination treatments for type 2 diabetes.

METHODS

Individual subject data from 1186 patients with type 2 diabetes [mean glycated haemoglobin (HbA1c) = 8.8%] treated with metformin, canagliflozin or canagliflozin + metformin were used. The baseline HbA1c versus ΔHbA1c relationships for monotherapy arms were determined using analysis of covariance and then used to predict efficacy in the combination arms by modelling how applying one treatment lowers the 'effective baseline HbA1c' for a second treatment. The model was further tested using data from several published combination studies.

RESULTS

The mean ΔHbA1c levels were -1.25, -1.33, -1.37, -1.77 and -1.81% with metformin, canagliflozin 100 mg, canagliflozin 300 mg, canagliflozin 100 mg/metformin and canagliflozin 300 mg/metformin, respectively. Using the monotherapy results, the predicted efficacy for the canagliflozin/metformin arms was within 10% of the observed values using the new model, whereas assuming simple additivity overpredicted efficacy in the combination arms by nearly 50%. For 10 other published initial combination studies, predictions from the new model [mean (standard error) predicted ΔHbA1c = 1.67% (0.14)] were much more consistent with observed values [ΔHbA1c = 1.72% (0.12)] than predictions based on assuming additivity [predicted ΔHbA1c = 2.19% (0.21)].

CONCLUSIONS

The less-than-additive efficacy commonly seen with initial combination treatments for type 2 diabetes can be largely explained by the impact of baseline HbA1c on the efficacy of individual treatments. Novel formulas have been developed for predicting the efficacy of combination treatments based on the efficacy of individual treatments and the baseline HbA1c of the target patients.

Evaluation of Bone Mineral Density and Bone Biomarkers in Patients With Type 2 Diabetes Treated With Canagliflozin

CONTEXT

Canagliflozin is a sodium glucose cotransporter 2 inhibitor developed to treat type 2 diabetes mellitus (T2DM).

OBJECTIVE

Our objective is to describe the effects of canagliflozin on bone mineral density (BMD) and bone biomarkers in patients with T2DM.

DESIGN

This was a randomized study, consisting of a 26-week, double-blind, placebo-controlled period and a 78-week, double-blind, placebo-controlled extension.

SETTING

This study was undertaken in 90 centers in 17 countries.

PATIENTS

Patients were aged 55-80 years (N = 716) and whose T2DM was inadequately controlled on a stable antihyperglycemic regimen.

INTERVENTIONS

Canagliflozin 100 or 300 mg or placebo were administered once daily.

OUTCOME AND MEASURES

BMD was assessed using dual-energy x-ray absorptiometry at weeks 26, 52, and 104. Bone strength was assessed using quantitative computed tomography and finite element analysis at week 52. Serum collagen type 1 β-carboxy-telopeptide, osteocalcin, and estradiol were assessed at weeks 26 and 52.

RESULTS

Canagliflozin doses of 100 and 300 mg were associated with a decrease in total hip BMD over 104 weeks, (placebo-subtracted changes: -0.9% and -1.2%, respectively), but not at other sites measured (femoral neck, lumbar spine, or distal forearm). No meaningful changes in bone strength were observed. At week 52, canagliflozin was associated with an increase in collagen type 1 β-carboxy-telopeptide that was significantly correlated with a reduction in body weight, an increase in osteocalcin, and, in women, a decrease in estradiol.

CONCLUSIONS

In older patients with T2DM, canagliflozin showed small but significant reductions in total hip BMD and increases in bone formation and resorption biomarkers, due at least in part to weight loss.

Sodium-Glucose Cotransporter Inhibitors: Effects on Renal and Intestinal Glucose Transport: From Bench to Bedside

Type 2 diabetes is a chronic disease with disabling micro- and macrovascular complications that lead to excessive morbidity and premature mortality. It affects hundreds of millions of people and imposes an undue economic burden on populations across the world. Although insulin resistance and insulin secretory defects play a major role in the pathogenesis of hyperglycemia, several other metabolic defects contribute to the initiation/worsening of the diabetic state. Prominent among these is increased renal glucose reabsorption, which is maladaptive in patients with diabetes. Instead of an increase in renal glucose excretion, which could ameliorate hyperglycemia, there is an increase in renal glucose reabsorption, which helps sustain hyperglycemia in patients with diabetes. The sodium-glucose cotransporter (SGLT) 2 inhibitors are novel antidiabetes agents that inhibit renal glucose reabsorption and promote glucosuria, thereby leading to reductions in plasma glucose concentrations. In this article, we review the long journey from the discovery of the glucosuric agent phlorizin in the bark of the apple tree through the animal and human studies that led to the development of the current generation of SGLT2 inhibitors.

Efficacy and Safety of Canagliflozin, a Sodium-Glucose Cotransporter 2 Inhibitor, as Add-on to Insulin in Patients With Type 1 Diabetes

OBJECTIVE

This study assessed the efficacy and safety of canagliflozin, a sodium-glucose cotransporter 2 inhibitor, as add-on to insulin in adults with type 1 diabetes.

RESEARCH DESIGN AND METHODS

This 18-week, double-blind, phase 2 study randomized 351 patients (HbA1c 7.0-9.0% [53-75 mmol/mol]) on multiple daily insulin injections or continuous subcutaneous insulin infusion to canagliflozin 100 or 300 mg or placebo. The primary end point was the proportion of patients achieving at week 18 both HbA1c reduction from baseline of ≥0.4% (≥4.4 mmol/mol) and no increase in body weight. Other end points included changes in HbA1c, body weight, and insulin dose, as well as hypoglycemia incidence. Safety was assessed by adverse event (AE) reports.

RESULTS

More patients had both HbA1c reduction ≥0.4% and no increase in body weight with canagliflozin 100 and 300 mg versus placebo at week 18 (36.9%, 41.4%, 14.5%, respectively; P < 0.001). Both canagliflozin doses provided reductions in HbA1c, body weight, and insulin dose versus placebo over 18 weeks. The incidence of hypoglycemia was similar across groups; severe hypoglycemia rates were low (1.7-6.8%). Overall incidence of AEs was 55.6%, 67.5%, and 54.7% with canagliflozin 100 and 300 mg and placebo; discontinuation rates were low (0.9-1.3%). Increased incidence of ketone-related AEs (5.1%, 9.4%, 0%), including the specific AE of diabetic ketoacidosis (DKA) (4.3%, 6.0%, 0%), was seen with canagliflozin 100 and 300 mg versus placebo.

CONCLUSIONS

Canagliflozin provided reductions in HbA1c, body weight, and insulin dose with no increase in hypoglycemia, but increased rates of ketone-related AEs, including DKA, in adults with type 1 diabetes inadequately controlled with insulin.

Effects of meal size on the release of GLP-1 and PYY after Roux-en-Y gastric bypass surgery in obese subjects with or without type 2 diabetes

Changes in gastrointestinal peptide release may play an important role in improving glucose control and reducing body weight following Roux-en-Y gastric bypass (RYGB), but the impact of low caloric intake on gut peptide release post-surgery has not been well characterized. The purpose of this study was to assess the relationships between low caloric intake and gut peptide release and how they were altered by RYGB. Obese females including ten normoglycemic (ON) and ten with type 2 diabetes mellitus (T2DM) (OD) were studied before, 1 week, and 3 months after RYGB. Nine lean, normoglycemic women were studied for comparison. Subjects were given three separate mixed meal challenges (MMCs; 75, 150, and 300 kcal). Plasma glucagon-like peptide 1 (GLP-1) and peptide YY (PYY) were analyzed. Prior to surgery, only minimal increases in GLP-1 and PYY were observed in response to the MMCs. After surgery, the peak GLP-1 concentration was progressively elevated in response to increasing meal sizes. The meal sizes had a statistically significant impact on elevation of GLP-1 incremental areas under the curve (ΔAUC) in both ON and OD at 1 week and 3 months post-surgery visits (p < 0.05 for all comparisons). The PYY ∆AUC was also significantly increased in a meal size-dependent manner in both ON and OD at both post-surgery visits (p < 0.05 for all comparisons). Meal sizes as small as 75-300 kcal, which cause minimal stimulation in GLP-1 or PYY release in the subjects before RYGB, are sufficient to provide statistically significant, meal size-dependent increases in the peptides post-RYGB both acutely and after meaningful weight loss occurred.

Canagliflozin: a sodium glucose co-transporter 2 inhibitor for the treatment of type 2 diabetes mellitus

The sodium glucose co-transporter 2 (SGLT2) inhibitor canagliflozin is a novel treatment option for adults with type 2 diabetes mellitus (T2DM). In patients with hyperglycemia, SGLT2 inhibition lowers plasma glucose levels by reducing the renal threshold for glucose (RTG ) and increasing urinary glucose excretion (UGE). Increased UGE is also associated with a mild osmotic diuresis and net caloric loss, which can lead to reductions in body weight and blood pressure (BP). After promising results from preclinical and phase I/II studies, the efficacy and safety of canagliflozin was evaluated in a comprehensive phase III development program in over 10,000 patients with T2DM on various background therapies. Canagliflozin improved glycemic control and provided reductions in body weight and BP versus placebo and active comparators in studies of up to 2 years' duration. Canagliflozin was generally well tolerated, with higher incidences of adverse events (AEs) related to the mechanism of action, including genital mycotic infections and AEs related to osmotic diuresis. Results from the preclinical and clinical studies led canagliflozin to be the first-in-class SGLT2 inhibitor approved in the United States, and support canagliflozin as a safe and effective therapeutic option across a broad range of patients with T2DM.

Effects of canagliflozin on body weight and relationship to HbA1c and blood pressure changes in patients with type 2 diabetes

AIMS/HYPOTHESIS

Canagliflozin, a sodium glucose co-transporter 2 inhibitor, reduces HbA1c, body weight and systolic BP (SBP) in patients with type 2 diabetes. As weight loss is known to reduce both HbA1c and SBP, these analyses were performed to evaluate the contribution of weight loss resulting from treatment with canagliflozin to HbA1c and SBP reductions in patients with type 2 diabetes.

METHODS

Pooled data from four placebo-controlled Phase 3 studies (N = 2,250) in patients with type 2 diabetes were used in the analyses. In each study, patients were treated with placebo, canagliflozin 100 mg or canagliflozin 300 mg, once daily for 26 weeks. Changes from baseline in body weight, HbA1c and SBP were measured at week 26, and the contribution of weight loss to the lowering of HbA1c and SBP was obtained using ANCOVA.

RESULTS

Canagliflozin 100 and 300 mg reduced mean body weight, HbA1c and SBP compared with placebo (p < 0.001 for each), and more patients had body-weight reductions >0%, ≥5% and ≥10% with canagliflozin treatment than with placebo. Weight-loss-independent and weight-loss-associated mechanisms contributed to HbA1c and SBP lowering with canagliflozin: ~85% of HbA1c lowering and ~60% of SBP lowering was independent of weight loss.

CONCLUSIONS/INTERPRETATION

In patients with type 2 diabetes, canagliflozin provided clinically meaningful body-weight reductions, and the weight loss contributed to reductions in HbA1c and SBP.

Determination of the renal threshold for glucose excretion in Familial Renal Glucosuria

BACKGROUND/AIMS

Familial Renal Glucosuria (FRG) is characterized by the presence of persistent isolated glucosuria in the absence of hyperglycemia. Mutations in SLC5A2, the gene coding for the sodium-glucose co-transporter 2 (SGLT2), are responsible for FRG. Phenotype/genotype correlations in FRG have mostly relied on the quantification of Urinary Glucose Excretion (UGE), which is dependent on both the filtered glucose load and the renal glucose reabsorptive capacity. In the current work, the renal threshold for glucose excretion (RTG) was determined in an FRG cohort, with the purpose of characterizing the impact of SGLT2 mutations on renal glucose transport.

METHODS

From January to December of 2013, eight FRG individuals with identified SLC5A2 mutations were enrolled. Patients were given a Mixed-Meal Tolerance Test during which blood glucose and UGE were measured over a 4 h period and the data was used to calculate RTG, according to a recently validated protocol.

RESULTS

In patients with homozygous mutations, RTG values were very low, with a mean (SD) of 0.95 (1.17) mmol/l, compared to commonly reported values of approximately 10-11.1 mmol/l in healthy subjects. In subjects with heterozygous mutations, mean (SD) RTG values were 4.91 (1.23) mmol/l, which are approximately one-half of the values in subjects without mutations.

CONCLUSIONS

In FRG, mutations in SLC5A2 lead to reductions in RTG and increases in UGE. Because determination of RTG is not influenced by the filtered glucose load, the calculated RTG values provide a more refined measure of the impact of mutations on renal glucose transport than can be obtained from UGE alone.

Pharmacodynamic differences between canagliflozin and dapagliflozin: results of a randomized, double-blind, crossover study

AIMS

To compare the pharmacodynamic effects of the highest approved doses of the sodium glucose co-transporter 2 (SGLT2) inhibitors canagliflozin and dapagliflozin on urinary glucose excretion (UGE), renal threshold for glucose excretion (RTG ) and postprandial plasma glucose (PPG) excursion in healthy participants in a randomized, double-blind, two-period crossover study.

METHODS

In each treatment period, participants (n = 54) received canagliflozin 300 mg or dapagliflozin 10 mg for 4 days (20 min before breakfast). A mixed-meal tolerance test (600 kcal; 75 g glucose) was performed at baseline and on day 4 of each treatment period to assess changes in incremental PPG (PPGΔAUC0-2 h ). We measured 24-h UGE and plasma glucose on day 4 to determine 24-h mean RTG .

RESULTS

Canagliflozin 300 mg and dapagliflozin 10 mg had similar effects on UGE and RTG for 4 h after dosing, but canagliflozin was associated with higher UGE and greater RTG reductions for the remainder of the day. Mean 24-h UGE was ∼25% higher with canagliflozin than with dapagliflozin (51.4 vs. 40.8 g), and 24-h mean RTG was ∼0.4 mmol/l (7 mg/dl) lower with canagliflozin than with dapagliflozin (3.79 vs. 4.17 mmol/l; p < 0.0001). Dapagliflozin had no effect on PPG excursion; canagliflozin delayed and reduced PPG excursion (between-treatment difference in PPGΔAUC0-2 h from baseline expressed as a percentage of baseline mean, -10.2%; p = 0.0122). Canagliflozin and dapagliflozin were generally well tolerated.

CONCLUSIONS

In healthy participants, canagliflozin 300 mg provided greater 24-h UGE, a lower RTG and smaller PPG excursions than dapagliflozin 10 mg.

Effect of the sodium glucose co-transporter 2 inhibitor canagliflozin on plasma volume in patients with type 2 diabetes mellitus

AIM

To evaluate the effects of canagliflozin on plasma volume, urinary glucose excretion (UGE), fasting plasma glucose (FPG), glycated haemoglobin (HbA1c) and additional measures of fluid/electrolyte balance in patients with type 2 diabetes on background therapy with metformin and angiotensin-converting enzyme inhibitors or angiotensin receptor blockers.

METHODS

Patients (N = 36) were randomized (1:1) to receive canagliflozin 300 mg or placebo for 12 weeks. Pharmacodynamic parameters were assessed at baseline and at weeks 1 and 12.

RESULTS

Increased 24-h UGE was seen in the canagliflozin group compared with a reduction in the placebo group at both week 1 (91.8 vs. -2.4 g) and week 12 (82.6 vs. -0.4 g). Canagliflozin also reduced both FPG and HbA1c. Reductions in body weight and blood pressure were observed at weeks 1 and 12. Canagliflozin decreased plasma volume compared with an increase with placebo at week 1 (-5.4 vs. 4.3%; p = 0.02), but this was largely attenuated at week 12 (4.6 vs. 5.8%; p = 0.76). A modest numerical increase in urine volume was observed with canagliflozin at week 1 that was attenuated at week 12; other measures of volume status (i.e. blood urea nitrogen, serum creatinine and haematocrit) remained modestly increased with canagliflozin at week 12.

CONCLUSION

Canagliflozin provided sustained effects on UGE and FPG over 12 weeks and a transient reduction in plasma volume that was largely attenuated by week 12.

Canagliflozin, a sodium glucose co-transporter 2 inhibitor, reduces post-meal glucose excursion in patients with type 2 diabetes by a non-renal mechanism: results of a randomized trial

OBJECTIVE

Canagliflozin is a sodium glucose co-transporter 2 inhibitor approved for treating patients with type 2 diabetes. This study evaluated renal and non-renal effects of canagliflozin on postprandial plasma glucose (PG) excursion in patients with type 2 diabetes inadequately controlled with metformin.

MATERIALS/METHODS

Patients (N=37) were randomized to a four-period crossover study with 3-day inpatient stays in each period and 2-week wash-outs between periods. Patients received Treatments (A) placebo/placebo, (B) canagliflozin 300 mg/placebo, (C) canagliflozin 300 mg/canagliflozin 300 mg, or (D) canagliflozin 300 mg/canagliflozin 150 mg on Day 2/Day 3 in one of four treatment sequences (similar urinary glucose excretion [UGE] expected for Treatments B-D). A mixed-meal tolerance test (MMTT) was given 20 minutes post-dose on Day 3 of each period.

RESULTS

A single dose of canagliflozin 300 mg reduced both fasting and postprandial PG compared with placebo, with generally similar effects on fasting PG and UGE observed for Treatments B-D. An additional dose of canagliflozin 300 mg (Treatment C), but not 150 mg (Treatment D), prior to the MMTT on Day 3 provided greater postprandial PG reduction versus placebo (difference in incremental glucose AUC0-2h, -7.5% for B vs A; -18.5% for C vs A; -12.0% [P = 0.012] for C vs B), leading to modestly greater reductions in total glucose AUC0-2h with Treatment C versus Treatment B or D. Canagliflozin was generally well tolerated.

CONCLUSIONS

These findings suggest that a non-renal mechanism (ie, beyond UGE) contributes to glucose lowering for canagliflozin 300 mg, but not 150 mg.

Pharmacodynamic effects of canagliflozin, a sodium glucose co-transporter 2 inhibitor, from a randomized study in patients with type 2 diabetes

Introduction

This randomized, double-blind, placebo-controlled, single and multiple ascending-dose study evaluated the pharmacodynamic effects and safety/tolerability of canagliflozin, a sodium glucose co-transporter 2 inhibitor, in patients with type 2 diabetes.

Methods

Patients (N = 116) discontinued their antihyperglycemic medications 2 weeks before randomization. Patients received canagliflozin 30, 100, 200, or 400 mg once daily or 300 mg twice daily, or placebo at 2 study centers in the United States and Germany, or canagliflozin 30 mg once daily or placebo at 1 study center in Korea, while maintaining an isocaloric diet for 2 weeks. On Days –1, 1, and 16, urinary glucose excretion (UGE), plasma glucose (PG), fasting PG (FPG), and insulin were measured. The renal threshold for glucose (RT_G) was calculated from UGE, PG, and estimated glomerular filtration rate. Safety was evaluated based on adverse event (AE) reports, vital signs, electrocardiograms, clinical laboratory tests, and physical examinations.

Results

Canagliflozin increased UGE dose-dependently (∼80–120 g/day with canagliflozin ≥100 mg), with increases maintained over the 14-day dosing period with each dose. Canagliflozin dose-dependently decreased RT_G, with maximal reductions to ∼4–5 mM (72–90 mg/dL). Canagliflozin also reduced FPG and 24-hour mean PG; glucose reductions were seen on Day 1 and maintained over 2 weeks. Plasma insulin reductions with canagliflozin were consistent with observed PG reductions. Canagliflozin also reduced body weight. AEs were transient, mild to moderate in intensity, and balanced across groups; 1 canagliflozin-treated female reported an episode of vaginal candidiasis. Canagliflozin did not cause hypoglycemia, consistent with the RT_G values remaining above the hypoglycemia threshold. At Day 16, there were no clinically meaningful changes in urine volume, urine electrolyte excretion, renal function, or routine laboratory test values.

Conclusions

Canagliflozin increased UGE and decreased RT_G, leading to reductions in PG, insulin, and body weight, and was generally well tolerated in patients with type 2 diabetes.

Trial Registration

ClinicalTrials.gov NCT00963768

Optimal back-extrapolation method for estimating plasma volume in humans using the indocyanine green dilution method

BACKGROUND

The indocyanine green dilution method is one of the methods available to estimate plasma volume, although some researchers have questioned the accuracy of this method.

METHODS

We developed a new, physiologically based mathematical model of indocyanine green kinetics that more accurately represents indocyanine green kinetics during the first few minutes postinjection than what is assumed when using the traditional mono-exponential back-extrapolation method. The mathematical model is used to develop an optimal back-extrapolation method for estimating plasma volume based on simulated indocyanine green kinetics obtained from the physiological model.

RESULTS

Results from a clinical study using the indocyanine green dilution method in 36 subjects with type 2 diabetes indicate that the estimated plasma volumes are considerably lower when using the traditional back-extrapolation method than when using the proposed back-extrapolation method (mean (standard deviation) plasma volume = 26.8 (5.4) mL/kg for the traditional method vs 35.1 (7.0) mL/kg for the proposed method). The results obtained using the proposed method are more consistent with previously reported plasma volume values.

CONCLUSIONS

Based on the more physiological representation of indocyanine green kinetics and greater consistency with previously reported plasma volume values, the new back-extrapolation method is proposed for use when estimating plasma volume using the indocyanine green dilution method.

Canagliflozin, a sodium glucose co-transporter 2 inhibitor, improves model-based indices of beta cell function in patients with type 2 diabetes

AIMS/HYPOTHESIS

In rodent models of diabetes, treatment with sodium glucose co-transporter 2 (SGLT2) inhibitors improves beta cell function. This analysis assessed the effects of the SGLT2 inhibitor, canagliflozin, on model-based measures of beta cell function in patients with type 2 diabetes.

METHODS

Data from three Phase 3 studies were analysed, in which: (Study 1) canagliflozin 100 and 300 mg were compared with placebo as monotherapy for 26 weeks; (Study 2) canagliflozin 100 and 300 mg were compared with placebo as add-on to metformin + sulfonylurea for 26 weeks; or (Study 3) canagliflozin 300 mg was compared with sitagliptin 100 mg as add-on to metformin + sulfonylurea for 52 weeks. In each study, a subset of patients was given mixed-meal tolerance tests at baseline and study endpoint, and model-based beta cell function parameters were calculated from plasma glucose and C-peptide.

RESULTS

In Studies 1 and 2, both canagliflozin doses increased beta cell glucose sensitivity compared with placebo. Placebo-subtracted least squares mean (LSM) (SEM) changes were 23 (9) and 18 (9) pmol min(-1) m(-2) (mmol/l)(-1) with canagliflozin 100 and 300 mg, respectively (p < 0.002, Study 1), and 16 (8) and 10 (9) pmol min(-1) m(-2) (mmol/l)(-1) (p < 0.02, Study 2). In Study 3, beta cell glucose sensitivity was minimally affected, but the insulin secretion rate at 9 mmol/l glucose increased to similar degrees from baseline with canagliflozin and sitagliptin [LSM (SEM) changes 38 (8) and 28 (9) pmol min(-1) m(-2), respectively; p < 0.05 for both].

CONCLUSIONS/INTERPRETATION

Treatment with canagliflozin for 6 to 12 months improved model-based measures of beta cell function in three separate Phase 3 studies.

TRIAL REGISTRATION

Clinicaltrials.gov NCT01081834 (Study 1); NCT01106625 (Study 2); NCT01137812 (Study 3).

Alteration of the glucagon axis in GPR120 (FFAR4) knockout mice: a role for GPR120 in glucagon secretion

GPR40 (FFAR1) and GPR120 (FFAR4) are G-protein-coupled receptors (GPCRs) that are activated by long chain fatty acids (LCFAs). GPR40 is expressed at high levels in islets and mediates the ability of LCFAs to potentiate glucose-stimulated insulin secretion (GSIS). GPR120 is expressed at high levels in colon, adipose, and pituitary, and at more modest levels in pancreatic islets. The role of GPR120 in islets has not been explored extensively. Here, we confirm that saturated (e.g. palmitic acid) and unsaturated (e.g. docosahexaenoic acid (DHA)) LCFAs engage GPR120 and demonstrate that palmitate- and DHA-potentiated glucagon secretion are greatly reduced in isolated GPR120 KO islets. Remarkably, LCFA potentiated glucagon secretion is similarly reduced in GPR40 KO islets. Compensatory changes in mRNA expression of GPR120 in GPR40 KO islets, and vice versa, do not explain that LCFA potentiated glucagon secretion seemingly involves both receptors. LCFA-potentiated GSIS remains intact in GPR120 KO islets. Consistent with previous reports, GPR120 KO mice are hyperglycemic and glucose intolerant; however, our KO mice display evidence of a hyperactive counter-regulatory response rather than insulin resistance during insulin tolerance tests. An arginine stimulation test and a glucagon challenge confirmed both increases in glucagon secretion and liver glucagon sensitivity in GPR120 KO mice relative to WT mice. Our findings demonstrate that GPR120 is a nutrient sensor that is activated endogenously by both saturated and unsaturated long chain fatty acids and that an altered glucagon axis likely contributes to the impaired glucose homeostasis observed in GPR120 KO mice.

Impaired decline in renal threshold for glucose during pregnancy - a possible novel mechanism for gestational diabetes mellitus

BACKGROUND

The renal threshold for glucose (RT(G)) is determined by the nephron's reabsorptive capacity. Glucose is reabsorbed through sodium-coupled glucose cotransporters in the proximal tubules. During pregnancy, renal glucose reabsorptive capacity decreases, possibly, due to reduced glucose transporter expression. Our hypothesis is that inadequate decrease in RT(G) during pregnancy will make women more prone to develop gestational diabetes mellitus (GDM).

METHODS

Pregnant women (n = 40) who were referred to our center for oral glucose tolerance test (OGTT) were included in the analysis. Plasma glucose levels and urinary glucose excretion were measured for 4 h after 100 g oral glucose load. These data were used to calculate RT(G) . The subjects were divided into two cohorts, GDM and non-GDM, according to the OGTT results. Mean RT(G) was compared between the two groups.

RESULTS

Fifteen (37.5%) of the women were diagnosed with GDM. Seventeen participants had only trace amounts of urinary glucose excretion, and no value of RT(G) could be determined; RT(G) was determined in the other 23 subjects. Among these 23 women, 13 were diagnosed as GDM, and 10 had normal OGTT. RT(G) was lower in the non-GDM women (146 ± 14 mg/dL) than in the GDM women (182 ± 18 mg/dL), p < 0.001.

CONCLUSIONS

Gestational diabetes mellitus is associated with higher RT(G) during pregnancy compared with non-GDM. These results support our hypothesis that inadequate decrease of the RT(G) may have a pathophysiological role in the development of GDM.

Canagliflozin lowers postprandial glucose and insulin by delaying intestinal glucose absorption in addition to increasing urinary glucose excretion: results of a randomized, placebo-controlled study

OBJECTIVE

Canagliflozin, a sodium glucose cotransporter (SGLT) 2 inhibitor, is also a low-potency SGLT1 inhibitor. This study tested the hypothesis that intestinal canagliflozin levels postdose are sufficiently high to transiently inhibit intestinal SGLT1, thereby delaying intestinal glucose absorption.

RESEARCH DESIGN AND METHODS

This two-period, crossover study evaluated effects of canagliflozin on intestinal glucose absorption in 20 healthy subjects using a dual-tracer method. Placebo or canagliflozin 300 mg was given 20 min before a 600-kcal mixed-meal tolerance test. Plasma glucose, (3)H-glucose, (14)C-glucose, and insulin were measured frequently for 6 h to calculate rates of appearance of oral glucose (RaO) in plasma, endogenous glucose production, and glucose disposal.

RESULTS

Compared with placebo, canagliflozin treatment reduced postprandial plasma glucose and insulin excursions (incremental 0- to 2-h area under the curve [AUC0-2h] reductions of 35% and 43%, respectively; P < 0.001 for both), increased 0- to 6-h urinary glucose excretion (UGE0-6h, 18.2 ± 5.6 vs. <0.2 g; P < 0.001), and delayed RaO. Canagliflozin reduced AUC RaO by 31% over 0 to 1 h (geometric means, 264 vs. 381 mg/kg; P < 0.001) and by 20% over 0 to 2 h (576 vs. 723 mg/kg; P = 0.002). Over 2 to 6 h, canagliflozin increased RaO such that total AUC RaO over 0 to 6 h was <6% lower versus placebo (960 vs. 1,018 mg/kg; P = 0.003). A modest (∼10%) reduction in acetaminophen absorption was observed over the first 2 h, but this difference was not sufficient to explain the reduction in RaO. Total glucose disposal over 0 to 6 h was similar across groups.

CONCLUSIONS

Canagliflozin reduces postprandial plasma glucose and insulin by increasing UGE (via renal SGLT2 inhibition) and delaying RaO, likely due to intestinal SGLT1 inhibition.

Pharmacokinetics and pharmacodynamics of canagliflozin, a sodium glucose co-transporter 2 inhibitor, in subjects with type 2 diabetes mellitus

This study characterized single- and multiple-dose pharmacokinetics of canagliflozin and its O-glucuronide metabolites (M5 and M7) and pharmacodynamics (renal threshold for glucose [RTG ], urinary glucose excretion [UGE0-24h ], and 24-hour mean plasma glucose [MPG0-24h ]) of canagliflozin in subjects with type 2 diabetes. Thirty-six randomized subjects received canagliflozin 50, 100, or 300 mg/day or placebo for 7 days. On Days 1 and 7, area under the plasma concentration-time curve and maximum observed plasma concentration (Cmax ) for canagliflozin and its metabolites increased dose-dependently. Half-life and time at which Cmax was observed were dose-independent. Systemic molar M5 exposure was half that of canagliflozin; M7 exposure was similar to canagliflozin. Steady-state plasma canagliflozin concentrations were reached by Day 4 in all active treatment groups. Pharmacodynamic effects were dose- and exposure-dependent. All canagliflozin doses decreased RTG , increased UGE0-24h , and reduced MPG0-24h versus placebo on Days 1 and 7. On Day 7, placebo-subtracted least-squares mean decreases in MPG0-24h ranged from 42-57 mg/dL with canagliflozin treatment. Adverse events (AEs) were balanced between treatments; no treatment-related serious AEs, AE-related discontinuations, or clinically meaningful adverse changes in routine safety evaluations occurred. The observed pharmacokinetic/pharmacodynamic profile of canagliflozin in subjects with type 2 diabetes supports a once-daily dosing regimen.

Validation of a novel method for determining the renal threshold for glucose excretion in untreated and canagliflozin-treated subjects with type 2 diabetes mellitus

CONTEXT

The stepwise hyperglycemic clamp procedure (SHCP) is the gold standard for measuring the renal threshold for glucose excretion (RT(G)), but its use is limited to small studies in specialized laboratories.

OBJECTIVE

The objective of the study was to validate a new method for determining RT(G) using data obtained during a mixed-meal tolerance test (MMTT) in untreated and canagliflozin-treated subjects with type 2 diabetes mellitus (T2DM).

DESIGN

This was an open-label study with 2 sequential parts.

SETTING

The study was performed at a single center in Germany.

PATIENTS

Twenty-eight subjects with T2DM were studied.

INTERVENTIONS

No treatment intervention was given in part 1. In part 2, subjects were treated with canagliflozin 100 mg/d for 8 days. In each part, subjects underwent an MMTT and a 5-step SHCP on consecutive days.

MAIN OUTCOME MEASURES

For both methods, RT(G) was estimated using measured blood glucose (BG) and urinary glucose excretion (UGE); estimated glomerular filtration rates were also used to determine RT(G) during the MMTT. The methods were compared using the concordance correlation coefficient and geometric mean ratios.

RESULTS

In untreated and canagliflozin-treated subjects, the relationship between UGE rate and BG was well described by a threshold relationship. Good agreement was obtained between the MMTT-based and SHCP-derived RT(G) values. The concordance correlation coefficient (for all subjects) was 0.94; geometric mean ratios (90% confidence intervals) for RT(G) values (MMTT/SHCP) were 0.93 (0.89-0.96) in untreated subjects and 1.03 (0.78-1.37) in canagliflozin-treated subjects. Study procedures and treatments were generally well tolerated in untreated and canagliflozin-treated subjects.

CONCLUSIONS

In both untreated and canagliflozin-treated subjects with T2DM, RT(G) can be accurately estimated from measured BG, UGE, and estimated glomerular filtration rates using an MMTT-based method.

Dose-ranging effects of canagliflozin, a sodium-glucose cotransporter 2 inhibitor, as add-on to metformin in subjects with type 2 diabetes

OBJECTIVE

To evaluate the effects of canagliflozin, a sodium-glucose cotransporter 2 inhibitor, in type 2 diabetes mellitus inadequately controlled with metformin monotherapy.

RESEARCH DESIGN AND METHODS

This was a double-blind, placebo-controlled, parallel-group, multicenter, dose-ranging study in 451 subjects randomized to canagliflozin 50, 100, 200, or 300 mg once daily (QD) or 300 mg twice daily (BID), sitagliptin 100 mg QD, or placebo. Primary end point was change in A1C from baseline through week 12. Secondary end points included change in fasting plasma glucose (FPG), body weight, and overnight urinary glucose-to-creatinine ratio. Safety and tolerability were also assessed.

RESULTS

Canagliflozin was associated with significant reductions in A1C from baseline (7.6-8.0%) to week 12: -0.79, -0.76, -0.70, -0.92, and -0.95% for canagliflozin 50, 100, 200, 300 mg QD and 300 mg BID, respectively, versus -0.22% for placebo (all P < 0.001) and -0.74% for sitagliptin. FPG was reduced by -16 to -27 mg/dL, and body weight was reduced by -2.3 to -3.4%, with significant increases in urinary glucose-to-creatinine ratio. Adverse events were transient, mild to moderate, and balanced across arms except for a non-dose-dependent increase in symptomatic genital infections with canagliflozin (3-8%) versus placebo and sitagliptin (2%). Urinary tract infections were reported without dose dependency in 3-9% of canagliflozin, 6% of placebo, and 2% of sitagliptin arms. Overall incidence of hypoglycemia was low.

CONCLUSIONS

Canagliflozin added onto metformin significantly improved glycemic control in type 2 diabetes and was associated with low incidence of hypoglycemia and significant weight loss. The safety/tolerability profile of canagliflozin was favorable except for increased frequency of genital infections in females.

Effect of canagliflozin on renal threshold for glucose, glycemia, and body weight in normal and diabetic animal models

BACKGROUND

Canagliflozin is a sodium glucose co-transporter (SGLT) 2 inhibitor in clinical development for the treatment of type 2 diabetes mellitus (T2DM).

METHODS

(14)C-alpha-methylglucoside uptake in Chinese hamster ovary-K cells expressing human, rat, or mouse SGLT2 or SGLT1; (3)H-2-deoxy-d-glucose uptake in L6 myoblasts; and 2-electrode voltage clamp recording of oocytes expressing human SGLT3 were analyzed. Graded glucose infusions were performed to determine rate of urinary glucose excretion (UGE) at different blood glucose (BG) concentrations and the renal threshold for glucose excretion (RT(G)) in vehicle or canagliflozin-treated Zucker diabetic fatty (ZDF) rats. This study aimed to characterize the pharmacodynamic effects of canagliflozin in vitro and in preclinical models of T2DM and obesity.

RESULTS

Treatment with canagliflozin 1 mg/kg lowered RT(G) from 415±12 mg/dl to 94±10 mg/dl in ZDF rats while maintaining a threshold relationship between BG and UGE with virtually no UGE observed when BG was below RT(G). Canagliflozin dose-dependently decreased BG concentrations in db/db mice treated acutely. In ZDF rats treated for 4 weeks, canagliflozin decreased glycated hemoglobin (HbA1c) and improved measures of insulin secretion. In obese animal models, canagliflozin increased UGE and decreased BG, body weight gain, epididymal fat, liver weight, and the respiratory exchange ratio.

CONCLUSIONS

Canagliflozin lowered RT(G) and increased UGE, improved glycemic control and beta-cell function in rodent models of T2DM, and reduced body weight gain in rodent models of obesity.

Roux-en-Y gastric bypass corrects hyperinsulinemia implications for the remission of type 2 diabetes

CONTEXT

Roux-en-Y gastric bypass (RYGB) has been shown to induce rapid and durable reversal of type 2 diabetes.

OBJECTIVE

The aim of the study was to investigate a possible mechanism for the remission of type 2 diabetes after RYGB.

DESIGN

A cross-sectional, nonrandomized, controlled study was conducted. Surgery patients were studied before RYGB and 1 wk and 3 months after surgery.

SETTING

This study was conducted at East Carolina University.

SUBJECTS

Subjects were recruited into three groups: 1) lean controls with no surgery [body mass index (BMI) < 25 kg/m²; n = 9], 2) severely obese type 2 diabetic patients (BMI > 35 kg/m²; n = 9), and 3) severely obese nondiabetic patients (BMI > 35 kg/m²; n = 9).

INTERVENTION

Intervention was RYGB.

RESULTS

One week after RYGB, diabetes was resolved despite continued insulin resistance (insulin sensitivity index was approximately 50% of lean controls) and reduced insulin secretion during an iv glucose tolerance test (acute insulin response to glucose was approximately 50% of lean controls). Fasting insulin decreased and was no different from lean control despite continued elevated glucose in the type 2 diabetic patients compared with lean.

CONCLUSIONS

After RYGB, fasting insulin decreases to levels like those of lean control subjects and diabetes is reversed (fasting blood glucose < 125 mg/dl). This leads us to propose that 1) exclusion of food from the foregut corrects hyperinsulinemia and 2) fasting insulin is dissociated from the influence of fasting glucose, insulin resistance, and BMI. The mechanisms for reversal of diabetes in the face of reduced insulin remain a paradox.

Canagliflozin, a novel inhibitor of sodium glucose co-transporter 2, dose dependently reduces calculated renal threshold for glucose excretion and increases urinary glucose excretion in healthy subjects

Canagliflozin, a potent, selective sodium glucose co-transporter 2 inhibitor in development for treatment of type 2 diabetes, lowers plasma glucose (PG) by lowering the renal threshold for glucose (RT(G) ) and increasing urinary glucose excretion (UGE). An ascending single oral-dose phase 1 study investigated safety, tolerability and pharmacodynamics of canagliflozin in healthy men (N = 63) randomized to receive canagliflozin (n = 48) or placebo (n = 15). Canagliflozin (10, 30, 100, 200, 400, 600 or 800 mg q.d. or 400 mg b.i.d.) was administered to eight cohorts (six subjects/cohort: canagliflozin; two subjects/cohort: placebo). Dose dependently, canagliflozin decreased calculated 24-h mean RT(G) with maximal reduction to approximately 60 mg/dl, and increased mean 24-h UGE. At doses >200 mg administered before breakfast, canagliflozin reduced postprandial PG and serum insulin excursions at that meal. Canagliflozin was generally well tolerated; most adverse events were mild and no hypoglycaemia was reported. These results support further study of canagliflozin.