Review Article
Cardiovascular benefits of the newer medications for treating type 2 diabetes mellitus Srikanth Yandrapalli, Wilbert S. Aronow Cardiology Division, Department of Medicine, Westchester Medical Center and New York Medical College, Valhalla, NY, USA Contributions: (I) Conception and design: All authors; (II) Administrative support: None; (III) Provision of study materials or patients: None; (IV) Collection and assembly of data: All authors; (V) Data analysis and interpretation: All authors; (VI) Manuscript writing: All authors; (VII) Final approval of manuscript: All authors. Correspondence to: Wilbert S. Aronow, MD, FACC, FAHA. Professor of Medicine, Cardiology Division, Westchester Medical Center and New York Medical College, Macy Pavilion, Room 141, Valhalla, NY 10595, USA. Email: [email protected].
Abstract: Diabetes mellitus is growing in pandemic proportions and is associated with significant morbidity, mortality, and health care expenditure. Type 2 diabetes mellitus (T2DM) is the most common, accounting for about 90–95% of diagnosed diabetes in United States adults. Individuals with T2DM have a 2- to 3-fold increased risk of cardiovascular (CV) events compared with their non-diabetic counterparts, and CV mortality is responsible for around 80% of the mortality in T2DM. Emerging evidence suggest that in T2DM patients, hyperglycemia plays a little role in the progression of CV disease, and metabolic risk factors like insulin resistance, hypertension, obesity, and dyslipidemia are the major culprits in the initiation and progression of CV disease. This calls for development of drugs which control hyperglycemia as well as the various metabolic risk factors in T2DM patients to improve CV outcomes. Recent clinical trials of glucagon-like peptide 1 receptor agonists (GLP-1 RAs) and sodium glucose cotransporter-2 (SGLT-2) inhibitors showed encouraging CV outcomes in T2DM patients, which are attributed to the diverse extrapancreatic effects of these medications. This review article will discuss the CV benefits of the newer incretin based therapies and SGLT-2 inhibitors as observed in their CV safety trials. As T2DM or insulin resistance syndrome, CV disease, and HF and frequently coexistent, it would be interesting to design studies evaluating the combinations of GLP-1 RAs, SGLT-2 inhibitors, and pioglitazone in T2DM patient at an elevated CV risk, and in non-diabetic patients with insulin resistance to study the possible CV protective role of these combinations. Keywords: Type 2 diabetes mellitus (T2DM); cardiovascular outcomes (CV outcomes); liraglutide; semaglutide; empagliflozin; pioglitazone Submitted Mar 10, 2017. Accepted for publication Jun 01, 2017. doi: 10.21037/jtd.2017.06.70 View this article at: http://dx.doi.org/10.21037/jtd.2017.06.70
Introduction Diabetes mellitus is growing in pandemic proportions and is associated with significant morbidity, mortality, and health care expenditures. It affects more than 29 million people in the United States (9.3% population), a trend if continues can result in every third adult having diabetes mellitus by 2050 (1). It affects around 415 million people worldwide, a number that is projected to increase to
© Journal of Thoracic Disease. All rights reserved.
642 million worldwide (12% population) by 2040, affecting one in every 10 adults (2). In the Unites States diabetes mellitus is the seventh leading cause of death, a number that is underreported (1). Per the International Diabetes Federation, 1 person dies from diabetes mellitus every 6 seconds around the world (2). The total cost of diabetes mellitus is estimated to be more than $245 billion in the United States and around $673 billion worldwide (1,2). Type 2 diabetes mellitus (T2DM) is the most common,
jtd.amegroups.com
J Thorac Dis 2017;9(7):2124-2134
Journal of Thoracic Disease, Vol 9, No 7 July 2017
accounting for about 90–95% of diagnosed diabetes in United States adults (1). Individuals with T2DM have a 2- to 3-fold increased risk of cardiovascular (CV) events compared with their non-diabetic counterparts, and CV mortality is responsible for around 80% of the mortality in T2DM (3,4). A metaanalysis showed that the relative risk (RR) for coronary heart disease or stroke has been estimated at 1.18% for every 1% increase in glycated hemoglobin (HbA1C) (5). Available evidence suggests that hyperglycemia is a weak risk factor for CV events, and tight glycemic control had very little effect on reducing macrovascular events and CVrelated death (6,7). Intensive glycemic control increased mortality without reducing CV events (8). In addition to hyperglycemia, individuals with T2DM can have other features of insulin resistance-metabolic syndrome like hypertension, lipid abnormalities, and obesity which are all associated with increased CV disease and stroke risk even in the absence of T2DM (9,10). Thus, the management of T2DM patients should include control of CV risk factors in addition to hyperglycemia to improve both macrovascular and microvascular complications and resulting morbidity and mortality. With the increasing prevalence of T2DM and metabolic syndrome, and associated significant CV disease and mortality, there is a need for novel diabetic medications which have a role in improving metabolic risk factors in addition to hyperglycemia. Metformin and pioglitazone has been shown to have a CV protective benefit via their effect on improving lipid profile, weight, and blood pressure (BP), and insulin sensitivity (11,12). Metformin decreases gluconeogenesis in liver, increases insulin sensitivity, and improves the efficacy of endogenous insulin (11). A meta-analysis suggesting that rosiglitazone was associated with significantly increased risk of myocardial infarction (MI) and CV-related death led to an intense debate about the CV safety of the antidiabetic drugs (13). This led to regulatory agencies requiring CV safety trials as part of the approval process for newer antidiabetic drugs (14,15). This review article will discuss the CV benefits of the newer incretin based therapies and sodium glucose cotransporter-2 (SGLT-2) inhibitors as observed in their CV safety trials. Incretin based therapies Incretins are insulinotropic intestinal hormones secreted into the blood by the enteroendocrine cells in response in oral glucose intake (16). These hormones then stimulate
© Journal of Thoracic Disease. All rights reserved.
2125
the secretion of insulin from the pancreatic ß-cells, a phenomenon called the incretin effect (16). Two incretins, glucose-dependent insulinotropic peptide and glucagon-like peptide 1 (GLP-1) were characterized and studied in human beings. Both the incretin hormones are rapidly degraded by dipeptidyl peptidase-4 (DPP-4) in the circulation (16). The insulinotropic effect of glucose-dependent insulinotropic peptide is deficient in patients with T2DM thereby limiting it from being a therapeutic target (16). The incretin effect of GLP-1 is better preserved in T2DM patients, thus making it a potential therapeutic target in this population (16). GLP-1 also inhibits gastric emptying, decreases appetite, inhibits glucagon secretion from pancreatic α-cells via a paracrine effect medicated by somatostatin release, and slows the rate of endogenous glucose production, all of which improve glycemic control in T2DM (16). Two approaches were devised to augment the beneficial role on incretins in T2DM. One approach is the use of exogenous GLP-1 agonists resistant to degradation by DPP-4. The other approach is the use of DPP-4 inhibitors to enhance the half-life and effects of endogenous GLP-1. GLP-1 receptor agonists (RAs) Currently available RAs include albiglutide once weekly, dulaglutide once weekly, exenatide twice daily, extended release exenatide once weekly, liraglutide once daily, and lixisenatide once daily. A comprehensive review of all head-to-head data indicates that liraglutide followed by exenatide appear to offer the best HbA1C (approximately 1–2%) and weight reduction (17). Retrospective analyses of data suggested a possible reduced likelihood of having a CV event over a 1- to 4-year period among patients who were treated with exenatide twice daily compared with other glucose-lowering agents (18). In 2 recent large randomized controlled trials, the GLP-1 RAs liraglutide and semaglutide showed remarkable CV benefit compared to placebo when added to patients with T2DM and high CV risk (19,20). The perceived CV benefit of GLP-1 RAs can be attributed to the extra-pancreatic pleotropic effects of GLP-1 on the CV system, and the favorable impact of GLP-1 RAs on important non-glycemic CV risk factors like BP, weight, and lipid profile. GLP-1 receptors are present on rodent and human cardiac myocytes, endothelial cells, and vascular smooth muscle cells (16). Numerous in vitro studies have demonstrated the protective effects of liraglutide and exenatide on endothelial cells independent of GLP-
jtd.amegroups.com
J Thorac Dis 2017;9(7):2124-2134
2126
Yandrapalli and Aronow. CV drugs for T2DM No established CVD
T2DM patients
Established CVD
In addition to first line diabetic therapies and lifestyle/risk factor modification
> Standard oral diabetic therapy (metformin/pioglitazone); > Aggressive risk factor modification with BP control, lipid control (statin), lifestyle interventions. > Randomized trials to evaluate benefit of GLP-1 agonists and SGLT-2 inhibitors in this group.
Consider GLP-1 agonist or SGLT-2 inhibitor as add on therapy in patients with CVD. Role of combination therapy based on risk factors/CVD is to be evaluated.
↑ eNOS, ↓ TNF alpha, ↓ PAI-1 etc
GLP-1 agonists Better improvements in vascular risk factors/outcomes and atherosclerosis.
↓ arterial stiffness.
HEART and VASCULATURE
improved endothelial dysfunction and ↓ atherosclerosis and intimal hyperplasia.
↓ BP, ↓weight, ↓urinary albumin secretion.
SGLT-2 inhibitors
Improve BP, lipid profile.
nephroprotective
Better improvements in HF outcomes.
↓ gastric emptying, appetite, glucagon secretion, glucose production.
KIDNEYS
↓ glucose reabsorption in the renal proximal tubule.
Figure 1 Approach to patients with type 2 diabetes mellitus (T2DM). Role of glucagon like peptide-1 (GLP-1) agonists and sodium glucose contransporter-2 (SGLT-2) inhibitors. CVD, cardiovascular disease; eNOS, endothelial nitric oxide synthase; TNF, tumor necrosis factor; PAI-1, plasminogen activator inhibitor 1; BP, blood pressure; ↓, decrease; ↑, increase.
1 RA glycemic and weight reduction effects (21,22). The favorable effects on endothelial cells is mediated via activation of endothelial nitric oxide synthase, and inhibition of tumor necrosis factor alpha, plasminogen activator inhibitor-1, various growth factors, and adhesion molecules. Through these GLP-1 receptor-dependent mechanisms, GLP-1 RAs improve endothelial dysfunction and attenuate atherosclerosis and intimal hyperplasia. Exenatide and liraglutide lowered BP, reduced myocardial infarct size, and improved systolic and diastolic cardiac function in various animal models of ischemia-reperfusion injury and congestive heart failure (HF) (16,21,22). Infusion of exenatide during two consecutive days in men with T2DM and HF led to significantly increased cardiac index and decreased pulmonary capillary wedge pressure compared to placebo (23) (Figure 1). The CV benefit of GLP-1 RAs in terms of risk factor improvement compared with placebo and most standard anti-diabetic agents was observed in human clinical studies. Treatment with liraglutide or exenatide was associated
© Journal of Thoracic Disease. All rights reserved.
with modest systolic BP reductions (21). In a meta-analysis of 33 trials (12,469 patients) in which 41% patients were treated with liraglutide and the rest with exenatide, GLP1 RA treatment achieved a greater systolic BP reduction than comparator therapy [weighted mean difference of 2.22 mmHg, 95% confidence interval (CI): −2.97 to −1.47] independent of baseline BP, weight loss, or improvement in HbA1C (24). Improvements in lipid profile by reducing triglycerides, apolipoproteins B-48, free fatty acids, lowdensity lipoprotein cholesterol (LDL-C), and total cholesterol was observed with GLP-1 RA treatment (21). In a meta-analysis of 35 trials, GLP-1 RAs were associated with modest reductions in LDL-C, total cholesterol, and triglycerides but no significant improvement in high density lipoprotein cholesterol (HDL-C) (25). Clinical studies of liraglutide and exenatide also demonstrated significant weight loss, and improvements in CV risk biomarkers like plasminogen activator inhibitor-1 and high-sensitivity C-reactive protein (16,21). The Evaluation of Lixisenatide in Acute Coronary
jtd.amegroups.com
J Thorac Dis 2017;9(7):2124-2134
Journal of Thoracic Disease, Vol 9, No 7 July 2017
Syndrome (ELIXA) trial randomized 606 T2DM patients who had a MI or who had been hospitalized for unstable angina within the previous 180 days to receive lixisenatide or placebo in addition to locally determined standards of care (26). Primary end-point was a composite of CV death, MI, stroke, or hospitalization for unstable angina. At 25-month follow up, the primary end-point event occurred in 13.4% patients in the lixisenatide group and in 13.2% in the placebo group [hazard ratio (HR) 1.02; 95% CI: 0.89 to 1.17], which showed the noninferiority of lixisenatide to placebo (P
Cardiovascular benefits of the newer medications for treating type 2 diabetes mellitus Srikanth Yandrapalli, Wilbert S. Aronow Cardiology Division, Department of Medicine, Westchester Medical Center and New York Medical College, Valhalla, NY, USA Contributions: (I) Conception and design: All authors; (II) Administrative support: None; (III) Provision of study materials or patients: None; (IV) Collection and assembly of data: All authors; (V) Data analysis and interpretation: All authors; (VI) Manuscript writing: All authors; (VII) Final approval of manuscript: All authors. Correspondence to: Wilbert S. Aronow, MD, FACC, FAHA. Professor of Medicine, Cardiology Division, Westchester Medical Center and New York Medical College, Macy Pavilion, Room 141, Valhalla, NY 10595, USA. Email: [email protected].
Abstract: Diabetes mellitus is growing in pandemic proportions and is associated with significant morbidity, mortality, and health care expenditure. Type 2 diabetes mellitus (T2DM) is the most common, accounting for about 90–95% of diagnosed diabetes in United States adults. Individuals with T2DM have a 2- to 3-fold increased risk of cardiovascular (CV) events compared with their non-diabetic counterparts, and CV mortality is responsible for around 80% of the mortality in T2DM. Emerging evidence suggest that in T2DM patients, hyperglycemia plays a little role in the progression of CV disease, and metabolic risk factors like insulin resistance, hypertension, obesity, and dyslipidemia are the major culprits in the initiation and progression of CV disease. This calls for development of drugs which control hyperglycemia as well as the various metabolic risk factors in T2DM patients to improve CV outcomes. Recent clinical trials of glucagon-like peptide 1 receptor agonists (GLP-1 RAs) and sodium glucose cotransporter-2 (SGLT-2) inhibitors showed encouraging CV outcomes in T2DM patients, which are attributed to the diverse extrapancreatic effects of these medications. This review article will discuss the CV benefits of the newer incretin based therapies and SGLT-2 inhibitors as observed in their CV safety trials. As T2DM or insulin resistance syndrome, CV disease, and HF and frequently coexistent, it would be interesting to design studies evaluating the combinations of GLP-1 RAs, SGLT-2 inhibitors, and pioglitazone in T2DM patient at an elevated CV risk, and in non-diabetic patients with insulin resistance to study the possible CV protective role of these combinations. Keywords: Type 2 diabetes mellitus (T2DM); cardiovascular outcomes (CV outcomes); liraglutide; semaglutide; empagliflozin; pioglitazone Submitted Mar 10, 2017. Accepted for publication Jun 01, 2017. doi: 10.21037/jtd.2017.06.70 View this article at: http://dx.doi.org/10.21037/jtd.2017.06.70
Introduction Diabetes mellitus is growing in pandemic proportions and is associated with significant morbidity, mortality, and health care expenditures. It affects more than 29 million people in the United States (9.3% population), a trend if continues can result in every third adult having diabetes mellitus by 2050 (1). It affects around 415 million people worldwide, a number that is projected to increase to
© Journal of Thoracic Disease. All rights reserved.
642 million worldwide (12% population) by 2040, affecting one in every 10 adults (2). In the Unites States diabetes mellitus is the seventh leading cause of death, a number that is underreported (1). Per the International Diabetes Federation, 1 person dies from diabetes mellitus every 6 seconds around the world (2). The total cost of diabetes mellitus is estimated to be more than $245 billion in the United States and around $673 billion worldwide (1,2). Type 2 diabetes mellitus (T2DM) is the most common,
jtd.amegroups.com
J Thorac Dis 2017;9(7):2124-2134
Journal of Thoracic Disease, Vol 9, No 7 July 2017
accounting for about 90–95% of diagnosed diabetes in United States adults (1). Individuals with T2DM have a 2- to 3-fold increased risk of cardiovascular (CV) events compared with their non-diabetic counterparts, and CV mortality is responsible for around 80% of the mortality in T2DM (3,4). A metaanalysis showed that the relative risk (RR) for coronary heart disease or stroke has been estimated at 1.18% for every 1% increase in glycated hemoglobin (HbA1C) (5). Available evidence suggests that hyperglycemia is a weak risk factor for CV events, and tight glycemic control had very little effect on reducing macrovascular events and CVrelated death (6,7). Intensive glycemic control increased mortality without reducing CV events (8). In addition to hyperglycemia, individuals with T2DM can have other features of insulin resistance-metabolic syndrome like hypertension, lipid abnormalities, and obesity which are all associated with increased CV disease and stroke risk even in the absence of T2DM (9,10). Thus, the management of T2DM patients should include control of CV risk factors in addition to hyperglycemia to improve both macrovascular and microvascular complications and resulting morbidity and mortality. With the increasing prevalence of T2DM and metabolic syndrome, and associated significant CV disease and mortality, there is a need for novel diabetic medications which have a role in improving metabolic risk factors in addition to hyperglycemia. Metformin and pioglitazone has been shown to have a CV protective benefit via their effect on improving lipid profile, weight, and blood pressure (BP), and insulin sensitivity (11,12). Metformin decreases gluconeogenesis in liver, increases insulin sensitivity, and improves the efficacy of endogenous insulin (11). A meta-analysis suggesting that rosiglitazone was associated with significantly increased risk of myocardial infarction (MI) and CV-related death led to an intense debate about the CV safety of the antidiabetic drugs (13). This led to regulatory agencies requiring CV safety trials as part of the approval process for newer antidiabetic drugs (14,15). This review article will discuss the CV benefits of the newer incretin based therapies and sodium glucose cotransporter-2 (SGLT-2) inhibitors as observed in their CV safety trials. Incretin based therapies Incretins are insulinotropic intestinal hormones secreted into the blood by the enteroendocrine cells in response in oral glucose intake (16). These hormones then stimulate
© Journal of Thoracic Disease. All rights reserved.
2125
the secretion of insulin from the pancreatic ß-cells, a phenomenon called the incretin effect (16). Two incretins, glucose-dependent insulinotropic peptide and glucagon-like peptide 1 (GLP-1) were characterized and studied in human beings. Both the incretin hormones are rapidly degraded by dipeptidyl peptidase-4 (DPP-4) in the circulation (16). The insulinotropic effect of glucose-dependent insulinotropic peptide is deficient in patients with T2DM thereby limiting it from being a therapeutic target (16). The incretin effect of GLP-1 is better preserved in T2DM patients, thus making it a potential therapeutic target in this population (16). GLP-1 also inhibits gastric emptying, decreases appetite, inhibits glucagon secretion from pancreatic α-cells via a paracrine effect medicated by somatostatin release, and slows the rate of endogenous glucose production, all of which improve glycemic control in T2DM (16). Two approaches were devised to augment the beneficial role on incretins in T2DM. One approach is the use of exogenous GLP-1 agonists resistant to degradation by DPP-4. The other approach is the use of DPP-4 inhibitors to enhance the half-life and effects of endogenous GLP-1. GLP-1 receptor agonists (RAs) Currently available RAs include albiglutide once weekly, dulaglutide once weekly, exenatide twice daily, extended release exenatide once weekly, liraglutide once daily, and lixisenatide once daily. A comprehensive review of all head-to-head data indicates that liraglutide followed by exenatide appear to offer the best HbA1C (approximately 1–2%) and weight reduction (17). Retrospective analyses of data suggested a possible reduced likelihood of having a CV event over a 1- to 4-year period among patients who were treated with exenatide twice daily compared with other glucose-lowering agents (18). In 2 recent large randomized controlled trials, the GLP-1 RAs liraglutide and semaglutide showed remarkable CV benefit compared to placebo when added to patients with T2DM and high CV risk (19,20). The perceived CV benefit of GLP-1 RAs can be attributed to the extra-pancreatic pleotropic effects of GLP-1 on the CV system, and the favorable impact of GLP-1 RAs on important non-glycemic CV risk factors like BP, weight, and lipid profile. GLP-1 receptors are present on rodent and human cardiac myocytes, endothelial cells, and vascular smooth muscle cells (16). Numerous in vitro studies have demonstrated the protective effects of liraglutide and exenatide on endothelial cells independent of GLP-
jtd.amegroups.com
J Thorac Dis 2017;9(7):2124-2134
2126
Yandrapalli and Aronow. CV drugs for T2DM No established CVD
T2DM patients
Established CVD
In addition to first line diabetic therapies and lifestyle/risk factor modification
> Standard oral diabetic therapy (metformin/pioglitazone); > Aggressive risk factor modification with BP control, lipid control (statin), lifestyle interventions. > Randomized trials to evaluate benefit of GLP-1 agonists and SGLT-2 inhibitors in this group.
Consider GLP-1 agonist or SGLT-2 inhibitor as add on therapy in patients with CVD. Role of combination therapy based on risk factors/CVD is to be evaluated.
↑ eNOS, ↓ TNF alpha, ↓ PAI-1 etc
GLP-1 agonists Better improvements in vascular risk factors/outcomes and atherosclerosis.
↓ arterial stiffness.
HEART and VASCULATURE
improved endothelial dysfunction and ↓ atherosclerosis and intimal hyperplasia.
↓ BP, ↓weight, ↓urinary albumin secretion.
SGLT-2 inhibitors
Improve BP, lipid profile.
nephroprotective
Better improvements in HF outcomes.
↓ gastric emptying, appetite, glucagon secretion, glucose production.
KIDNEYS
↓ glucose reabsorption in the renal proximal tubule.
Figure 1 Approach to patients with type 2 diabetes mellitus (T2DM). Role of glucagon like peptide-1 (GLP-1) agonists and sodium glucose contransporter-2 (SGLT-2) inhibitors. CVD, cardiovascular disease; eNOS, endothelial nitric oxide synthase; TNF, tumor necrosis factor; PAI-1, plasminogen activator inhibitor 1; BP, blood pressure; ↓, decrease; ↑, increase.
1 RA glycemic and weight reduction effects (21,22). The favorable effects on endothelial cells is mediated via activation of endothelial nitric oxide synthase, and inhibition of tumor necrosis factor alpha, plasminogen activator inhibitor-1, various growth factors, and adhesion molecules. Through these GLP-1 receptor-dependent mechanisms, GLP-1 RAs improve endothelial dysfunction and attenuate atherosclerosis and intimal hyperplasia. Exenatide and liraglutide lowered BP, reduced myocardial infarct size, and improved systolic and diastolic cardiac function in various animal models of ischemia-reperfusion injury and congestive heart failure (HF) (16,21,22). Infusion of exenatide during two consecutive days in men with T2DM and HF led to significantly increased cardiac index and decreased pulmonary capillary wedge pressure compared to placebo (23) (Figure 1). The CV benefit of GLP-1 RAs in terms of risk factor improvement compared with placebo and most standard anti-diabetic agents was observed in human clinical studies. Treatment with liraglutide or exenatide was associated
© Journal of Thoracic Disease. All rights reserved.
with modest systolic BP reductions (21). In a meta-analysis of 33 trials (12,469 patients) in which 41% patients were treated with liraglutide and the rest with exenatide, GLP1 RA treatment achieved a greater systolic BP reduction than comparator therapy [weighted mean difference of 2.22 mmHg, 95% confidence interval (CI): −2.97 to −1.47] independent of baseline BP, weight loss, or improvement in HbA1C (24). Improvements in lipid profile by reducing triglycerides, apolipoproteins B-48, free fatty acids, lowdensity lipoprotein cholesterol (LDL-C), and total cholesterol was observed with GLP-1 RA treatment (21). In a meta-analysis of 35 trials, GLP-1 RAs were associated with modest reductions in LDL-C, total cholesterol, and triglycerides but no significant improvement in high density lipoprotein cholesterol (HDL-C) (25). Clinical studies of liraglutide and exenatide also demonstrated significant weight loss, and improvements in CV risk biomarkers like plasminogen activator inhibitor-1 and high-sensitivity C-reactive protein (16,21). The Evaluation of Lixisenatide in Acute Coronary
jtd.amegroups.com
J Thorac Dis 2017;9(7):2124-2134
Journal of Thoracic Disease, Vol 9, No 7 July 2017
Syndrome (ELIXA) trial randomized 606 T2DM patients who had a MI or who had been hospitalized for unstable angina within the previous 180 days to receive lixisenatide or placebo in addition to locally determined standards of care (26). Primary end-point was a composite of CV death, MI, stroke, or hospitalization for unstable angina. At 25-month follow up, the primary end-point event occurred in 13.4% patients in the lixisenatide group and in 13.2% in the placebo group [hazard ratio (HR) 1.02; 95% CI: 0.89 to 1.17], which showed the noninferiority of lixisenatide to placebo (P
