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Program Editors Ralph Anthony DeFronzo, MD Professor of Medicine and Chief of the Diabetes Division University of Texas Health Science Center Audie L.

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Presentation on theme: "Program Editors Ralph Anthony DeFronzo, MD Professor of Medicine and Chief of the Diabetes Division University of Texas Health Science Center Audie L."— Presentation transcript:

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2 Program Editors Ralph Anthony DeFronzo, MD Professor of Medicine and Chief of the Diabetes Division University of Texas Health Science Center Audie L. Murphy Memorial Veterans Hospital San Antonio, Texas, USA Jaime A. Davidson, MD President, Worldwide Initiative for Diabetes Education Clinical Professor of Internal Medicine Division of Endocrinology University of Texas Southwestern Medical School Dallas, Texas, USA

3 Faculty Professor Rury Holman Professor of Diabetic Medicine Honorary Consultant Physician Diabetes Trials Unit University of Oxford Oxford, United Kingdom Professor Stefano Del Prato Professor of Endocrinology and Metabolism School of Medicine University of Pisa Pisa, Italy Professor Allan Vaag Chief Physician Steno Diabetes Center Gentofte, Denmark

4 SGLT2 Inhibition A Novel Treatment Strategy for Type 2 Diabetes

5 The Ominous Octet Islet  -cell Impaired Insulin Secretion NeurotransmitterDysfunction Decreased Glucose Uptake Islet  -cellIncreased Glucagon Secretion IncreasedLipolysis Increased Glucose Reabsorption IncreasedHGP Decreased Incretin Effect

6 Renal Glucose Reabsorption in Type 2 Diabetes Sodium-glucose cotransporter 2 (SGLT2) plays a role in renal glucose reabsorption in proximal tubule Renal glucose reabsorption is increased in type 2 diabetes Selective inhibition of SGLT2 increases urinary glucose excretion, reducing blood glucose Wright EM, et al. J Intern Med. 2007;261:32-43.

7 SGLT1 (180 L/day) (900 mg/L)=162 g/day 10% Glucose No Glucose S1 S3 Renal Handling of Glucose SGLT2 90%

8 GLUT2 AMG Uptake NGTT2DMNGTT2DM AMG=methyl-  -D-[U 14 C]-glucopyranoside; CPM=counts per minute. Rahmoune H, et al. Diabetes. 2005;54:3427-3434. SGLT2 NGTT2DM 0 2 6 8 0 500 1000 1500 2000 Normalized Glucose Transporter Levels CPM Increased Glucose Transporter Proteins and Activity in Type 2 Diabetes P<0.05 4

9 5 mmol/L Fasting Plasma Glucose Muscle  Normal Glucose Homeostasis Fat Liver Pancreas

10 Fasting Plasma Glucose Pathophysiology of Type 2 Diabetes 10 mmol/L Islet  -cell Impaired Insulin Secretion Insulin Resistance Increased HGP 5 mmol/L

11 Rationale for SGLT2 Inhibitors Inhibit glucose reabsorption in the renal proximal tubule Resultant glucosuria leads to a decline in plasma glucose and reversal of glucotoxicity This therapy is simple and nonspecific Even patients with refractory type 2 diabetes are likely to respond

12 Fasting Plasma Glucose Pathophysiology of Type 2 Diabetes 10 mmol/L Islet  -cell Impaired Insulin Secretion Insulin Resistance Increased HGP Glucosuria

13 Fasting Plasma Glucose Pathophysiology of Type 2 Diabetes 10 mmol/L Islet  -cell Impaired Insulin Secretion Insulin Resistance Increased HGP 5 mmol/L Glucosuria

14 SGLT1 (180 L/day) (900 mg/L)=162 g/day 10% Glucose No Glucose S1 S3 Renal Handling of Glucose SGLT2 90%

15 Sodium-Glucose Cotransporters SGLT1SGLT2SiteIntestine, kidneyKidney Sugar specificity Glucose or galactoseGlucose Glucose affinity High K m =0.4 mM Low K m =2 mM Glucose transport capacity LowHigh Role Dietary absorption of glucose and galactose Renal glucose reabsorption

16 Major transporter of glucose in the kidney Low affinity, high capacity for glucose Nearly exclusively expressed in the kidney Responsible for ~90% of renal glucose reabsorption in the proximal tubule Hediger MA, Rhoads DB. Physiol. Rev. 1994;74:993-1026. S1 Proximal Tubule Na + K+K+ ATPase Glucose GLUT2 Glucose SGLT2 BloodLumen Na + SGLT2 Mediates Glucose Reabsorption in the Kidney

17 Plasma Glucose Concentration (mmol/L) 155 Glucose Reabsorption and Excretion Splay Excretion Tm G 10 Actual Threshold Reabsorption Theoretical threshold Renal Glucose Handling

18 Rossetti L, et al. J Clin Invest. 1987;79:1510-1515. Effect of Phlorizin on Insulin Sensitivity in Diabetic Rats: Study Design Rat Group Pancreatectomy / Diabetic Status Phlorizin Meal Tolerance Test I (n=14) Sham Control –+ II (n=19) 90% Diabetes –+ III (n=10) 90% Diabetes ++ IV (n=4) 90% Diabetes + / – 10-12 days after discontinuation of phlorizin Phlorizin treatment period: 4-5 weeks Diet was same for all groups; body weight was similar across groups at end of study

19 Fasting Glucose (mmol/L) Diabetes +/- Phlorizin Diabetes + Phlorizin Diabetes Control * Fed Glucose (mmol/L) Diabetes +/- Phlorizin Diabetes + Phlorizin Diabetes Control *P<0.05 vs control and phlorizin. † P<0.001 vs control and phlorizin. Rossetti L, et al. J Clin Invest. 1987;79:1510-1515. Effect of Phlorizin on Fed and Fasting Plasma Glucose in Diabetic Rats † † 0 5 10 15 20 0 2 4 6 8

20 Glucose Uptake (mg/kg ∙ min) *P<0.001 vs control and phlorizin. Rossetti L, et al. J Clin Invest. 1987;79:1510-1515. Insulin-Mediated Glucose Uptake in Diabetic Rats Following Phlorizin Treatment Diabetes +/- Phlorizin Diabetes + Phlorizin DiabetesControl 20 25 30 35 40 * *

21 Mechanism of Action of SGLT2 Inhibitors Inhibition of SGLT2Reversal of glucotoxicity Insulin sensitivity in muscle ↑ GLUT4 translocation ↑ Insulin signaling Other Insulin sensitivity in liver ↓ Glucose- 6-phosphatase Gluconeogenesis Decreased Cori cycle ↓ PEP carboxykinase  -Cell function

22 Effect of Phlorizin on  -Cell Function in Diabetic Rats: Study Design Rat Group Pancreactomy / Diabetic Status Phlorizin I Sham Control – II 90% Diabetes – III 90% Diabetes 0.4 g/kg/day Sprague-Dawley male rats weighing 80-100 g Phlorizin treatment period: 3 weeks Arginine clamp (2 mM); hyperglycemic clamp (≥5.5 mmol/L) Rossetti L, et al. J Clin Invest. 1987;80:1037-1044.

23 First Phase Second Phase Control Diabetes + Phlorizin Diabetes 6 0 4 * * 2 Plasma Insulin (ng/mL ∙ min / g Pancreas) Plasma Insulin Response to Glucose *P<0.001 vs control. Rossetti L, et al. J Clin Invest. 1987;80:1037-1044.

24 Starke A, et al. Proc Natl Acad Sci. 1985;82:1544-1546.  Glucagon (pg/mL) Glucose Infusion Rate (mg/kg min) Diabetic + Phlorizin Diabetic -400 -200 0 241612862 Plasma Glucagon Concentration in Diabetic Dogs Before and After Phlorizin

25 Familial Renal Glucosuria: A Genetic Model of SGLT2 Inhibition

26 Familial Renal Glucosuria Presentation Glucosuria: 1-170 g/dayGlucosuria: 1-170 g/day AsymptomaticAsymptomaticBlood Normal glucose concentration No hypoglycemia or hypovolemiaNo hypoglycemia or hypovolemia Kidney / bladder No tubular dysfunction Normal histology and function Complications No increased incidence of –Chronic kidney disease –Diabetes –Urinary tract infection Santer R, et al. J Am Soc Nephrol. 2003;14:2873-2882; Wright EM, et al. J Intern Med. 2007;261:32-43.

27 Familial Renal Glucosuria Santer R, et al. J Am Soc Nephrol. 2003;14:2873-2882. Plasma Glucose Concentration (mmol/L) 155 Glucose Reabsorption 10 Type A Type B Normal Theoretical Observe d

28 Analysis of SGLT2 Gene in Patients With Renal Glucosuria Santer R, et al. J Am Soc Nephrol. 2003;14:2873-2882. 23 families analyzed for mutations In 23 families, 21 different mutations were detected in SGLT2 Cause of glucosuria in other 2 families remains unknown

29 GLUT2 AMG Uptake NGTT2DMNGTT2DM Rahmoune H, et al. Diabetes. 2005;54:3427-3434. SGLT2 NGTT2DM 0 2 6 8 0 500 1000 1500 2000 Normalized Glucose Transporter Levels CPM Increased Glucose Transporter Proteins and Activity in Type 2 Diabetes P<0.05 4

30 An adaptive response to conserve glucose (ie, for energy needs) becomes maladaptive in diabetes Moreover, the ability of the diabetic kidney to conserve glucose may be augmented in absolute terms by an increase in the renal reabsorption of glucoseImplications

31 SGLT2 Inhibitors for the Treatment of Type 2 Diabetes

32 Effect of SGLT2 Inhibition on Renal Glucose Handling Plasma Glucose Concentration (mmol/L) 155 Glucose Reabsorption and Excretion Splay Excretion Tm G 10 Actual Threshold Reabsorption Theoretical threshold

33 FPG (mg/dL) BaselineDay 8Day 15 Vehicle (n=6) 0.01 mg/kg (n=6) 0.1 mg/kg (n=6) 1 mg/kg (n=6) 10 mg/kg (n=6) 0 100 200 300 400 *P<0.05; † P<0.0001 vs vehicle. ZDF=Zucker diabetic fatty. Han S, et al. Diabetes. 2008;57:1723-1729; Whaley J, et al. Diabetes. 2007;56(suppl 2). Abstract 0559-P. Effects of SGLT2 on Fasting Plasma Glucose in ZDF Rats * * * † † * †

34 Hepatic Glucose Production (mg/kg min) Glucose Infusion Rate (mg/kg min) 0 1.0 2.0 3.0 4.0 0 2.0 4.0 6.0 8.0 CONDAPACONDAPA P<0.01 CON=controls; DAPA=dapagliflozin. Han S, et al. Diabetes. 2008;57:1723-1729. Effect SGLT2-I on Insulin-Stimulated Glucose Disposal and Hepatic Glucose Production in ZDF Rats

35 SGLT-2 Inhibitor Glucosuria Reduces HbA 1c : A Dose-Ranging Trial Study design 12 week, double-blind, placebo-controlled12 week, double-blind, placebo-controlled –Dapagliflozin: 2.5, 5, 10, 50 mg/day –Metformin XR: 1500 mg/day –Placebo Patients 389 drug-naive T2DM patients HbA 1c >7.0% MeasurementsFPG, PPG, HbA 1c List JF, et al. Diabetes Care. 2009;32:650-657.

36 Baseline HbA 1c (%)7.78.08.07.87.97.7 All comparisons vs placebo; no statistical comparisons with metformin were made. List JF, et al. Diabetes Care. 2008;2009;32:650-657. P<0.01 Effect of Dapagliflozin on HbA 1c Δ HbA 1c (%) P<0.01 -0.8 -0.6 -0.4 -0.2 0 DAPA 2.5 DAPA 5 DAPA 10 DAPA 50 PBO MET XR 1500

37 SGLT2-I: Glucosuric and Metabolic Effects Glucosuria 52-85 g/day ↑ 52-85 g/dayFPG ↓ 16-30 mg/dL PPG ↓ 23-29 mg/dL Body weight ↓ 2.2-3.2 kg (↓ 2.5%-3.4%) Urine volume ↑ 107-470 mL/day List JF, et al. Diabetes Care. 2009;32:650-657.

38 Adverse Events With Dapagliflozin PBO (n=54) Met 1500 mg QD (n=56) Dapa 2.5 mg QD (n=59) Dapa 5 mg QD (n=58) Dapa 10 mg QD (n=47) Dapa 20 mg QD (n=59) Dapa 50 mg QD (n=56) Hypoglycemia, n (%) 2 (4)5 (9)4 (7)6 (10)3 (6)4 (7) UTIs, n (%)3 (6)5 (9)3 (5)5 (9)5 (11)7 (12)5 (9) Genital infection, n (%) 0 (0)1 (2)2 (3)1 (2) 4 (7) Hypotensive event, n (%) 1 (2)2 (4)0 (0) 1 (2) UTI=urinary tract infection. List JF, et al. Diabetes Care. 2009;32:650-657.

39 Highly specific for the kidney and SGLT2 transporter ~80% reduction in SGLT2 mRNA/protein in Sprague- Dawley rats, ZDF rats, and dogs without any effect on SGLT1 Marked reduction in FPG, PPG, and HbA 1c in all three species No changes in plasma or urine electrolytes Wancewicz EV, et al. Diabetes. 2008;57(suppl 2). Abstract 334-OR. ISIS 388626 – A Specific SGLT2 Antisense Oligonucleotide

40 Unanswered Questions About SGLT2 Inhibition Durability The efficacy of SGLT2 inhibition may wane once blood glucose falls into the normal range Safety and tolerability The long-term safety of this class remains to be proven Risk of nocturia and genitourinary infections may limit use in some patients Renal impairment SGLT2 inhibition may not be effective in patients with renal impairment

41 SGLT2 Inhibition: Meeting Unmet Needs in Diabetes Care Weight Management Type 2 Diabetes Multiple Defects in Type 2 Diabetes Adverse Effects of Therapy Hyperglycemia CVD Risk (Lipid and Hypertension Control) Improvements in Glucose and Weight Support Other CVD Interventions Complements Action of Other Antidiabetic Agents Promotes Weight Loss Corrects a Novel Pathophysiologic Defect No Hypoglycemia Improves Glycemic Control

42 Conclusions SGLT2 inhibition represents a novel approach to the treatment of type 2 diabetes Studies in experimental models of diabetes have demonstrated that induction of glucosuria reverses glucotoxicity –Restores normoglycemia –Improves  -cell function and insulin sensitivity

43 Conclusions Genetic mutations leading to renal glucosuria support the long-term safety of SGLT2 inhibition in humans Early results with dapagliflozin provide proof of concept of the efficacy of SGLT2 inhibition in reducing both fasting and postprandial plasma glucose concentrations in type 2 diabetes

44 Overall Conclusions Understanding of the pathophysiology of type 2 diabetes is an evolving process As new concepts emerge, there is potential for new treatment modalities Optimal management of type 2 diabetes requires a multifaceted approach that targets multiple defects in glucose homeostasis


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