Saxagliptin and metformin XR combination therapy provides glycemic control over 24 hours in patients with T2DM inadequately controlled with metformin

Benefits and risks of drug combination therapy for diabetes mellitus and its complications: a comprehensive review

Diabetes is a chronic metabolic disease, and its therapeutic goals focus on the effective management of blood glucose and various complications. Drug combination therapy has emerged as a comprehensive treatment approach for diabetes. An increasing number of studies have shown that, compared with monotherapy, combination therapy can bring significant clinical benefits while controlling blood glucose, weight, and blood pressure, as well as mitigating damage from certain complications and delaying their progression in diabetes, including both type 1 diabetes (T1D), type 2 diabetes (T2D) and related complications. This evidence provides strong support for the recommendation of combination therapy for diabetes and highlights the importance of combined treatment. In this review, we first provided a brief overview of the phenotype and pathogenesis of diabetes and discussed several conventional anti-diabetic medications currently used for the treatment of diabetes. We then reviewed several clinical trials and pre-clinical animal experiments on T1D, T2D, and their common complications to evaluate the efficacy and safety of different classes of drug combinations. In general, combination therapy plays a pivotal role in the management of diabetes. Integrating the effectiveness of multiple drugs enables more comprehensive and effective control of blood glucose without increasing the risk of hypoglycemia or other serious adverse events. However, specific treatment regimens should be tailored to individual patients and implemented under the guidance of healthcare professionals.

Intensifying Treatment Beyond Monotherapy in Type 2 Diabetes Mellitus: Where Do Newer Therapies Fit?

PURPOSE OF REVIEW

Guidelines for a standard second diabetes medication for the treatment of type 2 diabetes (T2DM) have yet to be established. The rapid increase in the number of newer therapies available makes the choice more difficult. Thus, we reviewed clinical trial evidence evaluating newer therapies available for treatment intensification beyond monotherapy.

RECENT FINDINGS

Head-to-head studies comparing newer therapies versus traditional (i.e., sulfonylurea) approaches consistently find lower incidence of hypoglycemia and weight gain with newer therapies. Glucagon-like peptide-1 (GLP-1) receptor agonists and sodium-glucose co-transporter 2 (SGLT2) inhibitors demonstrate high glycemic efficacy, while merits of dipeptidyl peptidase-4 (DPP-4) inhibitors include their tolerability. Secondary effects (weight loss, cardiovascular outcomes, renal function) are of growing interest with newer therapies. Choices for treatment intensification in T2DM diabetes are numerous. Understanding the comparative evidence of newer treatment choices, as provided in this review, may help guide clinical decision making.

Cardiovascular Safety of Dipeptidyl-Peptidase IV Inhibitors: A Meta-Analysis of Placebo-Controlled Randomized Trials

BACKGROUND

Large randomized trials have shown conflicting evidence regarding the cardiovascular safety of dipeptidyl-peptidase 4 (DPP-4) inhibitors. Systematic reviews have been limited by incomplete data and inclusion of observational studies. This study aimed to systematically evaluate the cardiovascular safety of DPP-4 inhibitors in patients with type 2 diabetes.

METHODS

Electronic databases were searched for randomized trials that compared DPP-4 inhibitors versus placebo and reported cardiovascular outcomes. The main outcome assessed in this analysis was heart failure. Other outcomes included all-cause mortality, cardiovascular mortality, myocardial infarction, and ischemic stroke. Summary odds ratios (ORs) were primarily constructed using Peto's model.

RESULTS

A total of 90 trials with 66,730 patients were included. Compared with placebo, DPP-4 inhibitors were associated with a non-significant increased risk of heart failure [OR 1.11, 95% confidence interval (CI) 0.99-1.25, P = 0.07] at a mean of 108 weeks. The risk of all-cause mortality (OR 1.03, 95% CI 0.94-1.12, P = 0.53), cardiovascular mortality (OR 1.02, 95% CI 0.92-1.14, P = 0.72), myocardial infarction (OR 0.98, 95% CI 0.88-1.09, P = 0.69), and ischemic stroke (OR 0.99, 95% CI 0.85-1.15, P = 0.92) was similar between both groups.

CONCLUSION

In patients with type 2 diabetes, the safety profile of DPP-4 inhibitors is similar to placebo. As a class, there is only weak evidence for an increased risk of heart failure.

Rationale for treatment options for mealtime glucose control in patients with type 2 diabetes

While glycemic control is routinely assessed using HbA1c and fasting glucose measures, postprandial glucose (PPG) is also an important contributor of overall glycemia. Furthermore, PPG excursions have been linked to complications of diabetes. This review examines the effects of glucose-lowering therapies (including treatments administered at mealtime) on postprandial hyperglycemia in patients with type 2 diabetes. A PubMed search was conducted to identify clinical studies of treatments for mealtime glucose control in type 2 diabetes. Different treatments may have comparable effects on HbA1c but varying effects on PPG control and glucose fluctuations. Older classes of oral glucose-lowering treatments administered at mealtime to lower PPG include meglitinides and α-glucosidase inhibitors. Injectable therapies, including prandial insulin analogs, glucagon-like peptide-1 receptor agonists (GLP-1RAs), and the amylin analog pramlintide, all effectively target postprandial hyperglycemia. Compared with longer-acting GLP-1RAs, short-acting GLP-1RAs, such as exenatide twice daily and lixisenatide once daily, have a greater effect on PPG control, which is primarily mediated by a more pronounced effect on delayed gastric emptying. Dipeptidyl peptidase-4 inhibitors and sodium-glucose cotransporter 2 inhibitors also reduce postprandial hyperglycemia. To achieve more physiologically normal glycemic control, choice of therapy should ideally aim to address daily glucose fluctuations, including hyperglycemic peaks and hypoglycemic troughs, and long-term glycemic control.

Racial/ethnic disparities in prevalence and care of patients with type 2 diabetes mellitus

BACKGROUND

As of 2012, nearly 10% of Americans had diabetes mellitus. People with diabetes are at approximately double the risk of premature death compared with those in the same age groups without the condition. While the prevalence of diabetes has risen across all racial/ethnic groups over the past 30 years, rates are higher in minority populations. The objective of this review article is to evaluate the prevalence of diabetes and disease-related comorbidities as well as the primary endpoints of clinical studies assessing glucose-lowering treatments in African Americans, Hispanics, and Asians.

METHODS

As part of our examination of this topic, we reviewed epidemiologic and outcome publications. Additionally, we performed a comprehensive literature search of clinical trials that evaluated glucose-lowering drugs in racial minority populations. For race/ethnicity, we used the terms African American, African, Hispanic, and Asian. We searched PubMed for clinical trial results from 1996 to 2015 using these terms by drug class and specific drug. Search results were filtered qualitatively.

RESULTS

Overall, the majority of publications that fit our search criteria pertained to native Asian patient populations (i.e., Asian patients in Asian countries). Sulfonylureas; the α-glucosidase inhibitor, miglitol; the biguanide, metformin; and the thiazolidinedione, rosiglitazone have been evaluated in African American and Hispanic populations, as well as in Asians. The literature on other glucose-lowering drugs in non-white races/ethnicities is more limited.

CONCLUSIONS

Clinical data are needed for guiding diabetes treatment among racial minority populations. A multi-faceted approach, including vigilant screening in at-risk populations, aggressive treatment, and culturally sensitive patient education, could help reduce the burden of diabetes on minority populations. To ensure optimal outcomes, educational programs that integrate culturally relevant approaches should highlight the importance of risk-factor control in minority patients.

Overview of saxagliptin efficacy and safety in patients with type 2 diabetes and cardiovascular disease or risk factors for cardiovascular disease

Most individuals with type 2 diabetes mellitus have or will develop multiple independent risk factors for cardiovascular disease, particularly coronary artery disease (CAD). CAD is the leading cause of morbidity and mortality among individuals with type 2 diabetes mellitus, and treating these patients is challenging. The risk of hypoglycemia, weight gain, or fluid retention with some diabetes medications should be considered when developing a treatment plan for individuals with a history of CAD or at risk for CAD. Dipeptidyl peptidase-4 inhibitors are oral antihyperglycemic agents that inhibit the breakdown of the incretin hormones glucagon-like peptide-1 and glucose-dependent insulinotropic polypeptide, resulting in increased glucose-dependent insulin secretion and suppression of glucagon secretion. Saxagliptin is a potent and selective dipeptidyl peptidase-4 inhibitor that improves glycemic control and is generally well tolerated when used as monotherapy and as add-on therapy to other antihyperglycemic medications. This review summarizes findings from recently published post hoc analyses of saxagliptin clinical trials that have been conducted in patients with and without a history of cardiovascular disease and in patients with and without various risk factors for cardiovascular disease. The results show that saxagliptin was generally well tolerated and consistently improved glycemic control, as assessed by reductions from baseline in glycated hemoglobin, fasting plasma glucose concentration, and postprandial glucose concentration, regardless of the presence or absence of baseline cardiovascular disease, hypertension, statin use, number of cardiovascular risk factors, or high Framingham 10-year cardiovascular risk score.

Saxagliptin efficacy and safety in patients with type 2 diabetes receiving concomitant statin therapy

AIMS

To examine whether concomitant statin therapy affects glycemic control with saxagliptin 2.5 and 5mg/d in patients with type 2 diabetes mellitus (T2DM).

METHODS

Efficacy and safety were analyzed post hoc for pooled data from 9 saxagliptin randomized, placebo-controlled trials with a primary 24-week treatment period (4 monotherapy, 2 add-on to metformin, 1 each add-on to a sulfonylurea, thiazolidinedione, or insulin±metformin). Safety was also assessed in an 11-study, 24-week pool and an extended 20-study pool, which included 9 additional 4- to 52-week randomized studies. Comparisons were performed for patient groups defined by baseline statin use.

RESULTS

Saxagliptin produced greater mean reductions in glycated hemoglobin than placebo, with no interaction between treatment and baseline statin use (P=0.47). In patients receiving saxagliptin 2.5 and 5mg and placebo, the proportion of patients with ≥1 adverse event (AE) was 78.1%, 64.0%, and 63.2%, respectively, in patients with any statin use and 70.6%, 57.9%, and 55.0% in patients with no statin use. Serious AEs, deaths, and symptomatic confirmed hypoglycemia (fingerstick glucose ≤50mg/dL) were few and similar, irrespective of baseline statin use.

CONCLUSIONS

Saxagliptin improves glycemic control and is generally well tolerated in patients with T2DM, irrespective of concomitant statin therapy.

Safety of saxagliptin: events of special interest in 9156 patients with type 2 diabetes mellitus

BACKGROUND

A post hoc pooled analysis was undertaken to evaluate the safety of saxagliptin in patients with type 2 diabetes mellitus, with attention to events of special interest for dipeptidyl peptidase-4 inhibitors.

METHODS

Pooled analyses were performed for 20 randomized controlled studies (N = 9156) of saxagliptin as monotherapy or add-on therapy, and a subset of 11 saxagliptin + metformin studies. Adverse events and events of special interest (gastrointestinal adverse events, infections, hypersensitivity, pancreatitis, skin lesions, lymphopenia, thrombocytopenia, hypoglycaemia, bone fracture, severe cutaneous adverse reactions, opportunistic infection, angioedema, malignancy, worsening renal function, and specific laboratory events) were assessed; incidence rates (events/100 person-years) and incidence rates ratios (saxagliptin/control) were calculated (Mantel-Haenszel method).

RESULTS

In both pooled datasets, the incidence rates for deaths, serious adverse events, discontinuations due to adverse events, pancreatitis, malignancy, and most other events of special interest, excepting bone fractures and hypersensitivity, were similar between treatments, with 95% confidence intervals (CIs) for incidence rates ratios including 1. In the 20-study pool, the incidence rates per 100 person-years was higher with saxagliptin versus control for bone fractures [1.1 vs 0.6; incidence rates ratio (95% CI), 1.81 (1.04-3.28)] and hypersensitivity adverse events [1.3 vs 0.8; 1.67 (1.01-2.87)].

CONCLUSIONS

Pooled data from 20 studies confirm that saxagliptin has a favourable safety and benefit-risk profile.

A randomized controlled trial of the efficacy and safety of twice-daily saxagliptin plus metformin combination therapy in patients with type 2 diabetes and inadequate glycemic control on metformin monotherapy

BACKGROUND

To compare the safety and efficacy of saxagliptin 2.5 mg twice daily (BID) versus placebo add-on therapy to metformin immediate release (IR) in patients with type 2 diabetes and inadequate glycemic control with metformin alone.

METHODS

This multicenter, 12-week, double-blind, parallel-group trial enrolled adult outpatients with type 2 diabetes (glycated hemoglobin [HbA1c] 7.0%-10.0%) on stable metformin IR monotherapy (≥1500 mg, BID for ≥8 weeks). Patients were randomized to double-blind saxagliptin 2.5 mg BID or placebo added on to metformin IR following a 2-week, single-blind, placebo add-on therapy lead-in period. The primary end point was the change from baseline to week 12 in HbA1c. Key secondary end points included change from baseline to week 12 in fasting plasma glucose (FPG) and the proportion of patients achieving HbA1c <7.0% or HbA1c ≤ 6.5% at week 12. Efficacy was analyzed in all patients who received randomized study drug with ≥1 postbaseline assessment. Safety was assessed in all treated patients.

RESULTS

In total, 74 patients were randomized to double-blind saxagliptin add-on therapy and 86 to placebo add-on therapy. At week 12, least-squares mean changes (95% CI) from baseline HbA1c (adjusted for baseline HbA1c) were significantly greater (P = 0.006) in the saxagliptin + metformin group -0.56% (-0.74% to -0.38%) versus the placebo + metformin group -0.22% (-0.39% to -0.06%). Adjusted mean changes from baseline in FPG were numerically greater with saxagliptin versus placebo; the difference (95% CI) -9.5 mg/dL (-21.7 to 2.7) was not statistically significant (P = 0.12). A numerically greater proportion of patients in the saxagliptin group than the placebo group achieved HbA1c < 7.0% (37.5% vs 24.2%) or HbA1c ≤6.5% (24.6% vs 10.7%). There were no unexpected safety findings. Hypoglycemia occurred in 4 patients (5.4%) in the saxagliptin group and 1 patient (1.2%) in the placebo group; confirmed hypoglycemia (symptoms plus fingerstick glucose ≤50 mg/dL) occurred in 1 patient in the placebo group.

CONCLUSIONS

Addition of saxagliptin 2.5 mg BID to metformin therapy in patients with type 2 diabetes and inadequate glycemic control on metformin monotherapy reduced HbA1c compared with placebo added to metformin, with an adverse events profile similar to placebo and no unexpected safety findings.

TRIAL REGISTRATION

ClinicalTrials.gov NCT00885378.

Assessment of the cardiovascular safety of saxagliptin in patients with type 2 diabetes mellitus: pooled analysis of 20 clinical trials

BACKGROUND

It is important to establish the cardiovascular (CV) safety profile of novel antidiabetic drugs.

METHODS

Pooled analyses were performed of 20 randomized controlled studies (N = 9156) of saxagliptin as monotherapy or add-on therapy in patients with type 2 diabetes mellitus (T2DM) as well as a subset of 11 saxagliptin + metformin studies. Adjudicated major adverse CV events (MACE; CV death, myocardial infarction [MI], and stroke) and investigator-reported heart failure were assessed, and incidence rates (IRs; events/100 patient-years) and IR ratios (IRRs; saxagliptin/control) were calculated (Mantel-Haenszel method).

RESULTS

In pooled datasets, the IR point estimates for MACE and individual components of CV death, MI, and stroke favored saxagliptin, but the 95% CI included 1. IRR (95% CI) for MACE in the 20-study pool was 0.74 (0.45, 1.25). The Cox proportional hazard ratio (95% CI) was 0.75 (0.46, 1.21), suggesting no increased risk of MACE in the 20-study pool. In the 11-study saxagliptin + metformin pool, the IRR for MACE was 0.93 (0.44, 1.99). In the 20-study pool, the IRR for heart failure was 0.55 (0.27, 1.12).

CONCLUSIONS

Analysis of pooled data from 20 clinical trials in patients with T2DM suggests that saxagliptin is not associated with an increased CV risk.

Pathogenesis and management of postprandial hyperglycemia: role of incretin-based therapies

Postprandial plasma glucose concentrations are an important contributor to glycemic control. There is evidence suggesting that postprandial hyperglycemia may be an independent risk factor for cardiovascular disease. Glucagon-like peptide-1 (GLP-1) receptor agonists and dipeptidyl peptidase-4 (DPP-4) inhibitors are antidiabetic agents that predominantly reduce postprandial plasma glucose levels. DPP-4 inhibitors are associated with fewer gastrointestinal side effects than GLP-1 receptor agonists and are administered orally, unlike GLP-1 analogs, which are administered as subcutaneous injections. GLP-1 receptor agonists are somewhat more effective than DPP-4 inhibitors in reducing postprandial plasma glucose and are usually associated with significant weight loss. For these reasons, GLP-1 receptor agonists are generally preferred over DPP-4 inhibitors as part of combination treatment regimens in patients with glycated hemoglobin levels above 8.0%. This article reviews the pathogenesis of postprandial hyperglycemia, the mechanisms by which GLP-1 receptor agonists and DPP-4 inhibitors reduce postprandial plasma glucose concentrations, and the results of recent clinical trials (ie, published 2008 to October 2012) that evaluated the effects of these agents on postprandial plasma glucose levels when evaluated as monotherapy compared with placebo or as add-on therapy to metformin, a sulfonylurea, or insulin. Findings from recent clinical studies suggest that both GLP-1 receptor agonists and DPP-4 inhibitors could become valuable treatment options for optimizing glycemic control in patients unable to achieve glycated hemoglobin goals on basal insulin, with the added benefits of weight loss and a low risk of hypoglycemia.

Adding Saxagliptin to Metformin Extended Release (XR) or Uptitration of Metformin XR: Efficacy on Daily Glucose Measures

INTRODUCTION

Saxagliptin added to metformin extended release (XR) and uptitrated metformin XR were evaluated for their impact on daily glucose measurements and their tolerability in patients with type 2 diabetes mellitus (T2DM) inadequately controlled with metformin monotherapy.

METHODS

Patients aged 18-78 years on metformin 850-1,500 mg with glycated hemoglobin (HbA1c) 7.5-11.5% at screening were eligible for this double-blind, active-controlled study. Patients were stabilized on metformin XR 1,500 mg before randomization. Patients with HbA1c 7-11% and fasting plasma glucose (FPG) ≥126 mg/dL after a 4- 8-week lead-in period were randomly assigned to saxagliptin 5 mg + metformin XR 1,500 mg or metformin XR 500 mg + metformin XR 1,500 mg (uptitrated metformin XR). The primary end point was change from baseline to week 4 in 24-h mean weighted glucose (MWG). Secondary end points were changes from baseline to week 4 in 2-h postprandial glucose (PPG) and FPG.

RESULTS

At week 4, the adjusted mean ± SE change from baseline in 24-h MWG was -19.0 ± 5.7 mg/dL (95% CI -30.3 to -7.6) for saxagliptin + metformin XR and -8.2 ± 6.0 mg/dL (95% CI -20.0 to 3.7) for uptitrated metformin XR. Mean changes from baseline in 2-h PPG and FPG were numerically greater with saxagliptin + metformin XR versus uptitrated metformin XR. The incidence of adverse events was lower with saxagliptin + metformin XR (17.4%) versus uptitrated metformin XR (31.9%) mainly due to differences in gastrointestinal adverse event incidence (2.2% vs 10.6%, respectively). There were no reports of confirmed hypoglycemia in either group.

CONCLUSION

In this 4-week study in patients with T2DM inadequately controlled with metformin monotherapy, saxagliptin added to metformin XR demonstrated a trend for improvement in measures of daily glycemic control, with fewer gastrointestinal adverse events, compared with uptitrated metformin.

Effects of saxagliptin added to sub-maximal doses of metformin compared with uptitration of metformin in type 2 diabetes: the PROMPT study

OBJECTIVE

The PROMPT study compared efficacy and tolerability of two treatment intensification strategies: adding saxagliptin or uptitrating metformin monotherapy, in patients with type 2 diabetes (T2D) and inadequate glycaemic control on a sub-maximal metformin dose.

RESEARCH DESIGN AND METHODS

In this double-blind, 24-week study, metformin-tolerant patients with T2D on metformin monotherapy were randomised to receive fixed-dose metformin 1500 mg/day, plus either add-on saxagliptin 5 mg/day (SAXA-MET) or a two-step metformin uptitration (MET-UP) to a maximum dose (2500 mg/day).

CLINICAL TRIAL REGISTRATION

NCT01006590.

MAIN OUTCOME MEASURES

Primary: absolute change from baseline in glycated haemoglobin A(1c) (HbA(1c)) (Week 24). Secondary: proportion of patients achieving a therapeutic glycaemic response (Week 24); change from baseline in fasting plasma glucose (Week 24); safety and tolerability. Exploratory analyses comprised three patient-related questionnaires, including the validated 5-dimension Digestive Health Status Index (DHSI).

RESULTS

A total of 286 patients were randomised: (SAXA-MET: 147; MET-UP: 139). Baseline mean (SD) HbA(1c): 7.71 (0.85; SAXA-MET); 7.80 (0.82; MET-UP). Adjusted mean reductions from baseline in HbA(1c) (Week 24): -0.47% (SAXA-MET); -0.38% (MET-UP); mean (95% CI) difference in treatment effect, -0.10% (-0.26, 0.07); p = 0.260. The proportion of patients (95% CI) achieving a therapeutic glycaemic response (HbA(1c) < 7%): 43.8% (34.8, 49.6) (SAXA-MET) vs. 35.0% (29.0, 43.8) (MET-UP). Of the five DHSI domains, mean (95% CI) differences were observed for diarrhoea-predominant score (+0.8 [-2.5, 4.0] vs. +7.9 [4.6, 11.2]) and dysmotility score (-0.5 [-2.0, 1.0] vs. +1.9 [0.3, 3.4]), (SAXA-MET and MET-UP, respectively). The most common adverse event was diarrhoea: 6.1% (SAXA-MET) vs. 12.2% (MET-UP).

CONCLUSIONS

In metformin-tolerant patients with T2D (inadequately controlled on sub-maximal metformin monotherapy), saxagliptin was well tolerated. Although HbA(1c) reduction was not significantly different between treatment groups, the lower occurrence of gastrointestinal symptoms in the SAXA-MET group suggests that saxagliptin add-on treatment may be a suitable alternative treatment strategy to metformin uptitration.

Adding saxagliptin to extended-release metformin vs. uptitrating metformin dosage

AIM

To investigate whether patients taking metformin for type 2 diabetes mellitus (T2DM) have improved glycaemic control without compromising tolerability by adding an agent with a complementary mechanism of action vs. uptitrating metformin.

METHODS

Adults with T2DM and glycated haemoglobin (HbA1c) between 7.0 and 10.5% receiving metformin extended release (XR) 1500 mg/day for ≥8 weeks were randomized to receive saxagliptin 5 mg added to metformin XR 1500 mg (n = 138) or metformin XR uptitrated to 2000 mg/day (n = 144). Endpoints were change from baseline to week 18 in HbA1c (primary), 120-min postprandial glucose (PPG), fasting plasma glucose (FPG) and the proportion of patients achieving HbA1c <7%.

RESULTS

At week 18, the adjusted mean reduction from baseline HbA1c was -0.88% for saxagliptin + metformin XR and -0.35% for uptitrated metformin XR (difference, -0.52%; p < 0.0001). For 120-min PPG and FPG, differences in adjusted mean change from baseline between saxagliptin + metformin XR and uptitrated metformin XR were -1.3 mmol/l (-23.32 mg/dl) (p = 0.0013) and -0.73 mmol/l (-13.18 mg/dl) (p = 0.0030), respectively. More patients achieved HbA1c <7.0% with saxagliptin + metformin XR than with uptitrated metformin XR (37.2 vs. 26.1%; p = 0.0459). The proportions of patients experiencing any adverse events (AEs) were generally similar between groups; neither group showed any notable difference in hypoglycaemia or gastrointestinal AEs.

CONCLUSION

Adding saxagliptin to metformin XR provided superior glycaemic control compared with uptitrating metformin XR without the emergence of additional safety concerns.

Saxagliptin for the treatment of type 2 diabetes mellitus: focus on recent studies

Dipeptidyl peptidase-4 (DPP-4) inhibitors are a class of oral antidiabetic drugs that improve glycemic control without causing weight gain or increasing hypoglycemic risk in patients with type 2 diabetes (T2DM). The efficacy and tolerability of saxagliptin, a once-daily DPP-4 inhibitor, administered as monotherapy, as add-on therapy to metformin, a sulfonylurea, or a thiazolidinedione, and as initial combination therapy with metformin, was demonstrated in pivotal 24-week clinical trials. Additional information about the clinical profile of saxagliptin was recently obtained from extension studies, head-to-head clinical trials, and post-hoc analyses. In extension studies, the efficacy and tolerability of add-on saxagliptin and initial saxagliptin-plus-metformin therapy were maintained for up to 102 weeks. Saxagliptin plus metformin was shown to be non-inferior to glipizide plus metformin in lowering glycated hemoglobin from base-line, with reduced body-weight and lower hypoglycemic risk. Post-hoc analyses indicate that the clinical benefits of saxagliptin extend across demographic subgroups and special populations. A meta-analysis found no evidence for increased cardiovascular risk in T2DM patients exposed to saxagliptin for > 1 year. On the basis of this clinical profile, saxagliptin is an attractive option for initial and add-on therapy for T2DM patients with inadequate glycemic control.

Saxagliptin plus metformin combination therapy

Metformin is considered to be the first-line drug therapy for the management of Type 2 diabetes. Incretin-based therapies, and especially dipeptidyl peptidase-4 inhibitors, offer new opportunities after failure of metformin. An extensive literature search was performed to analyze all clinical trials combining saxagliptin with metformin. Saxagliptin and metformin may be administered together, either separately or in fixed-dose combination, as saxagliptin added to metformin or as an initial combination. Saxagliptin and metformin are not prone to pharmacokinetic drug-drug interactions and fixed-dose combination allows dosing of one single pill (Kombiglyze^® XR) or two pills (Komboglyze^®) per day. Both compounds exert pharmacodynamic complementary actions. Their coadministration improves blood glucose control (fasting plasma glucose, postprandial glucose and glycated hemoglobin) more potently than either compound separately. Tolerance is good without hypoglycemia, weight gain and further increase in metformin-related gastrointestinal adverse events. The combination saxagliptin plus metformin may be used as first-line or second-line therapy in the management of Type 2 diabetes.

Saxagliptin: A dipeptidyl peptidase-4 inhibitor in the treatment of type 2 diabetes mellitus

Type 2 diabetes mellitus (T2DM) is a metabolic disorder characterized by insulin deficiency or resistance. Management starts with single oral antidiabetic drug (OAD) but eventually switch over to combination therapy because of progressive β-cell dysfunction. Hypoglycemia, weight gain, and adverse cardiovascular events are major limitations of the available OADs (Sulfonylureas [SUs], thiazolidinediones [TZDs]). Saxagliptin, a reversible, competitive dipeptidyl peptidase-4 inhibitor, is recently approved agent in the treatment of T2DM. It acts by preventing the degradation of glucagon-like peptide – 1 and hence increases secretion of insulin and decreases secretion of glucagon. It is a well-tolerated agent with commonly reported adverse events which include upper respiratory tract infection, urinary tract infection, and headache. Hypoglycemia, weight gain, and adverse cardiovascular events are negligible as compared with other OADs. In clinical studies, saxagliptin was found to be effective and well tolerated when used as a monotherapy as well as in combination with metformin, SUs and TZDs. It is administered in the dose range of 2.5 to 5 mg once a day regardless of meal. Dosage reduction is required in patients having moderate to severe renal impairment as well as with concurrent administration of strong CYP3A4/5 inhibitors. To conclude, saxagliptin because of its novel mechanism of action (preserving beta cell function) and better tolerability profile seems to be a promising agent in the treatment of T2DM, especially in the early stage of the disease, but long-term clinical studies are required to prove its status in the management of T2DM.

The design and rationale of the saxagliptin assessment of vascular outcomes recorded in patients with diabetes mellitus-thrombolysis in myocardial infarction (SAVOR-TIMI) 53 study

OBJECTIVES

Saxagliptin, a dipeptidyl peptidase 4 inhibitor, improves glycemic control in patients with type 2 diabetes mellitus (T2DM) by increasing endogenous active, intact glucagon-like peptide 1 and glucose-dependent insulinotropic polypeptide in response to food, which augments insulin secretion and decreases glucagon release.

RESEARCH DESIGN AND METHODS

SAVOR-TIMI 53 is a phase 4, randomized, double-blind, placebo-controlled trial conducted in 25 countries that is designed to evaluate the safety and efficacy of saxagliptin during long-term treatment of approximately 16,500 patients with T2DM. Eligible patients who are either treatment naive or on any background antidiabetic treatment (except incretin therapy) with history of established cardiovascular (CV) disease or multiple risk factors are randomized 1:1 to saxagliptin 5 mg QD (2.5 mg in subjects with moderate/severe renal impairment) or matching placebo, stratified by qualifying disease state. The primary end point is the composite of CV death, nonfatal myocardial infarction, or nonfatal ischemic stroke. The trial will continue until approximately 1,040 primary end points accrue, providing 85% power to identify a 17% relative reduction of the primary end point with saxagliptin versus placebo and 98% power to test for noninferiority of saxagliptin versus placebo (reject the upper limit of 95% CI for a hazard ratio <1.3 at a 1-sided α of .025).

CONCLUSION

SAVOR-TIMI 53 is testing the hypothesis that treatment with saxagliptin is safe and reduces CV events in high-risk patients with T2DM.