Saxagliptin given in combination with metformin as initial therapy improves glycaemic control in patients with type 2 diabetes compared with either monotherapy: a randomized controlled trial

DPP-4 inhibitor therapy and bone fractures in people with Type 2 diabetes - A systematic review and meta-analysis

AIM

Fracture risk is higher in older adults with Type 2 diabetes mellitus (T2DM). Oral glucose-lowering medications have different effects on bone metabolism. The purpose of this study is to appraise the evidence from literature and determine the effect of dipeptidyl peptidase-4 (DPP-4) inhibitor on the risk of developing bone fractures.

METHODS

Using Boolean search terms, the search strategy combined synonyms of 'fracture' and 'DPP-4 inhibitor'. Comprehensive electronic databases which include EMBASE, MEDLINE, the EMA and the WHO ICTRP databases were searched for randomised controlled trial (RCT) studies which compared a DPP-4 inhibitor with an active comparator or placebo amongst patients with T2DM. Meta-analysis was performed to compare DPP-4 inhibitor with either an active comparator or a placebo. The outcome measure was the presence or absence of fracture.

RESULTS

The search yielded 5061 records relating to fractures and DPP-4 inhibitor, from which 51 eligible RCTs were selected for meta-analysis (N=36,402). Thirty-seven (37) studies compared DPP-4 inhibitor with placebo (n=23,974), while fourteen (14) studies (n=12,428) compared DPP-4 inhibitor with an active comparator. The mean age of patients was 57.5±5.4years, the average glycated haemoglobin (HbA1c) was 8.2%, while the average BMI was 30±2kg/m(2). Overall, there was no significant association of fracture events with the use of DPP-4 inhibitor when compared with placebo (OR; 0.82, 95% CI 0.57-1.16, P=0.9) or when DPP-4 inhibitor was compared against an active comparator (OR; 1.59, 95% CI 0.91-2.80, P=0.9).

CONCLUSION

This study offers a larger, up-to-date review of the subject. The meta-analysis showed that there was no significant association between DPP-4 inhibitor use and the incidence of fractures.

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.

Incretin-Based Therapy for Diabetes: What a Cardiologist Needs to Know

Incretin-based therapies are effective glucose-lowering drugs that have an increasing role in the treatment of type 2 diabetes because of their efficacy, safety, and ease of use. Both glucagon-like peptide-1 receptor agonists and dipeptidyl peptidase-4 inhibitors are commonly used for glycemic control as adjuncts to metformin, other oral antiglycemic agents, or insulin. Glucagon-like peptide-1 receptor agonists may have additional effects, such as weight loss, that may be advantageous in obese patients. There is a large body of evidence from randomized controlled clinical trials supporting the cardiovascular safety of dipeptidyl peptidase-4 inhibitors and some glucagon-like peptide-1 receptor agonists, at least in the short term. However, concerns have been raised, particularly regarding their safety in patients with heart failure. In this review, the authors provide a brief but practical evidence-based analysis of the use of incretin-based agents in patients with diabetes, their efficacy, and cardiovascular safety.

Initial Combination Therapy With Canagliflozin Plus Metformin Versus Each Component as Monotherapy for Drug-Naïve Type 2 Diabetes

OBJECTIVE

This study assessed the efficacy/safety of canagliflozin (CANA), a sodium-glucose cotransporter 2 (SGLT2) inhibitor, plus metformin extended-release (MET) initial therapy in drug-naïve type 2 diabetes.

RESEARCH DESIGN AND METHODS

This 26-week, double-blind, phase 3 study randomized 1,186 patients to CANA 100 mg (CANA100)/MET, CANA 300 mg (CANA300)/MET, CANA100, CANA300, or MET. Primary end point was change in HbA(1c) at week 26 for combinations versus monotherapies. Secondary end points included noninferiority in HbA(1c) lowering with CANA monotherapy versus MET; changes in fasting plasma glucose, body weight, and blood pressure; and proportion of patients achieving HbA(1c) <7.0% (<53 mmol/mol).

RESULTS

From mean baseline HbA(1c) of 8.8% (73 mmol/mol), CANA100/MET and CANA300/MET significantly lowered HbA(1c) versus MET (median dose, 2,000 mg/day) by -1.77%, -1.78%, and -1.30% (-19.3, -19.5, and -14.2 mmol/mol; differences of -0.46% and -0.48% [-5.0 and -5.2 mmol/mol]; P = 0.001) and versus CANA100 and CANA300 by -1.37% and -1.42% (-15.0 and -15.5 mmol/mol; differences of -0.40% and -0.36% [-4.4 and -3.9 mmol/mol]; P = 0.001). CANA100 and CANA300 monotherapy met noninferiority for HbA(1c) lowering and had significantly more weight loss versus MET (-2.8, -3.7, and -1.9 kg [-3.0%, -3.9%, and -2.1%]; P = 0.016 and P = 0.002). Greater attainment of HbA(1c) <7.0% (50%, 57%, and 43%) and significantly more weight loss (-3.2, -3.9, and -1.9 kg [-3.5%, -4.2%, and -2.1%]; P = 0.001) occurred with CANA100/MET and CANA300/MET versus MET. The incidence of adverse events (AEs) related to SGLT2 inhibition (genital mycotic infections, osmotic diuresis- and volume depletion-related AEs) was higher in the CANA arms (0.4-4.4%) versus MET (0-0.8%). AE-related discontinuation rates were 1.3-3.0% across groups. The incidence of hypoglycemia was 3.0-5.5% in the CANA arms and 4.6% with MET.

CONCLUSIONS

Initial therapy with CANA plus MET was more effective and generally well tolerated versus each monotherapy in drug-naïve type 2 diabetes. CANA monotherapy demonstrated noninferior HbA1c lowering versus MET.

A systematic review of the safety of incretin-based therapies in type 2 diabetes

INTRODUCTION

Large randomized clinical trials have demonstrated that incretin-based therapies provide effective glycemic control in type 2 diabetes. Long-term safety assessments are ongoing.

METHODS

This systematic review of incretin-based therapy safety is based on 112 randomized clinical trials of duration ≥26 weeks published between January 2000 and February 2015 in patients with type 2 diabetes.

RESULTS

As expected, hypoglycemia rates were lower with dipeptidyl peptidase-4 inhibitors (DPP-4is) and glucagon-like peptide-1 receptor agonists (GLP-1 RAs) versus other oral antidiabetic drugs and insulin. The most common adverse events were infection and infestation (DPP-4is) and gastrointestinal (GLP-1 RAs). Pancreatitis cases were rare across all studies and, in the SAVOR-TIMI and EXAMINE trials, pancreatitis rates were similar in DPP-4i- and placebo-treated patients. No thyroid tumors were reported, and increased risk of cardiovascular events was not associated with DPP-4is in SAVOR-TIMI and EXAMINE, albeit over a short follow-up period.

CONCLUSIONS

Overall, incretin-based therapies were well tolerated; however, their long-term safety profile should continue to be periodically assessed.

Dipeptidyl peptidase-4 inhibitors and risk of heart failure in type 2 diabetes: systematic review and meta-analysis of randomised and observational studies

OBJECTIVES

To examine the association between dipeptidyl peptidase-4 (DPP-4) inhibitors and the risk of heart failure or hospital admission for heart failure in patients with type 2 diabetes.

DESIGN

Systematic review and meta-analysis of randomised and observational studies.

DATA SOURCES

Medline, Embase, Cochrane Central Register of Controlled Trials, and ClinicalTrials.gov searched up to 25 June 2015, and communication with experts.

ELIGIBILITY CRITERIA

Randomised controlled trials, non-randomised controlled trials, cohort studies, and case-control studies that compared DPP-4 inhibitors against placebo, lifestyle modification, or active antidiabetic drugs in adults with type 2 diabetes, and explicitly reported the outcome of heart failure or hospital admission for heart failure.

DATA COLLECTION AND ANALYSIS

Teams of paired reviewers independently screened for eligible studies, assessed risk of bias, and extracted data using standardised, pilot tested forms. Data from trials and observational studies were pooled separately; quality of evidence was assessed by the GRADE approach.

RESULTS

Eligible studies included 43 trials (n=68,775) and 12 observational studies (nine cohort studies, three nested case-control studies; n=1,777,358). Pooling of 38 trials reporting heart failure provided low quality evidence for a possible similar risk of heart failure between DPP-4 inhibitor use versus control (42/15,701 v 33/12,591; odds ratio 0.97 (95% confidence interval 0.61 to 1.56); risk difference 2 fewer (19 fewer to 28 more) events per 1000 patients with type 2 diabetes over five years). The observational studies provided effect estimates generally consistent with trial findings, but with very low quality evidence. Pooling of the five trials reporting admission for heart failure provided moderate quality evidence for an increased risk in patients treated with DPP-4 inhibitors versus control (622/18,554 v 552/18,474; 1.13 (1.00 to 1.26); 8 more (0 more to 16 more)). The pooling of adjusted estimates from observational studies similarly suggested (with very low quality evidence) a possible increased risk of admission for heart failure (adjusted odds ratio 1.41, 95% confidence interval 0.95 to 2.09) in patients treated with DPP-4 inhibitors (exclusively sitagliptin) versus no use.

CONCLUSIONS

The relative effect of DPP-4 inhibitors on the risk of heart failure in patients with type 2 diabetes is uncertain, given the relatively short follow-up and low quality of evidence. Both randomised controlled trials and observational studies, however, suggest that these drugs may increase the risk of hospital admission for heart failure in those patients with existing cardiovascular diseases or multiple risk factors for vascular diseases, compared with no use.

Dapagliflozin combination therapy in type 2 diabetes mellitus

Type 2 diabetes mellitus (T2DM) is a progressive disease, and most patients ultimately require two or more antidiabetes drugs in addition to lifestyle changes to achieve and maintain glycemic control. Current consensus statements and guidelines recommend metformin as first-line pharmacotherapy for the treatment of T2DM in most patients. When glycemic control cannot be maintained with metformin alone, the sequential, stepwise addition of other agents is recommended. Agents such as thiazolidinediones or sulfonylureas have typically been added to metformin therapy. Although effective in reducing glycated hemoglobin, these drugs are often associated with adverse effects, most notably weight gain, and in the case of sulfonylureas, hypoglycemia. Sodium-glucose cotransporter 2 inhibitors, such as dapagliflozin, are the newest class of antidiabetes drugs approved for the treatment of T2DM. Dapagliflozin effectively improves glycemic control by increasing the renal excretion of excess glucose. In clinical trials, dapagliflozin has been well tolerated and has additional benefits of weight loss, low risk of hypoglycemia and reduction in blood pressure. This review discusses the clinical evidence and rationale for the use of dapagliflozin as add-on therapy in T2DM. The results suggest that dapagliflozin add-on therapy is a promising new treatment option for a wide range of patients with T2DM. Results from an ongoing cardiovascular outcomes trial are needed to establish the long-term safety of dapagliflozin.

Utility of Saxagliptin in the Treatment of Type 2 Diabetes: Review of Efficacy and Safety

INTRODUCTION

Type 2 diabetes mellitus (T2DM) is a complex disease in which multiple organs and hormones contribute to the pathogenesis of disease. The intestinal hormone, glucagon-like peptide-1 (GLP-1), secreted in response to nutrient ingestion, increases insulin secretion from pancreatic β-cells and reduces glucagon secretion from pancreatic α-cells. GLP-1 is inactivated by the dipeptidyl peptidase-4 (DPP-4) enzyme. Saxagliptin is a DPP-4 inhibitor that prevents the degradation of endogenous GLP-1 and prolongs its actions on insulin and glucagon secretion. This article reviews the efficacy and safety of saxagliptin in patients with T2DM.

METHODS

A PubMed literature search was conducted to identify relevant, peer-reviewed saxagliptin clinical trial articles published between January 2008 and June 2015. Search terms included "saxagliptin" and "DPP-4 inhibitors".

RESULTS

In clinical trials, saxagliptin significantly improved glycemic control when used as monotherapy or as add-on therapy to other antidiabetes agents and was associated with a low risk of hypoglycemia. In a large cardiovascular (CV) outcomes trial (SAVOR) in patients with T2DM and with established CV disease or multiple CV risk factors, saxagliptin neither increased nor decreased CV risk compared with placebo as assessed by the composite end point of death from CV causes, nonfatal myocardial infarction, or nonfatal stroke. Unexpectedly, more patients in the saxagliptin (3.5%) than in the placebo group (2.8%) were hospitalized for heart failure.

CONCLUSION

Saxagliptin demonstrated statistically significant and clinically meaningful improvements in glycemic control and a low risk of hypoglycemia in patients with T2DM. However, this positive profile needs to be tempered by the observation of an increased risk of hospitalization for heart failure in the SAVOR trial. Results from ongoing CV outcome trials with other DPP-4 inhibitors may provide additional data on how best to manage patients with T2DM who are at risk for heart failure.

FUNDING

AstraZeneca LP.

Dipeptidyl Peptidase-4 Inhibitors in Diverse Patient Populations With Type 2 Diabetes

PURPOSE

The purpose of this review is to discuss the clinical evidence for dipeptidyl peptidase-4 (DPP-4) inhibitors and to better define their use in treating type 2 diabetes mellitus (T2DM), including in special populations, such as the elderly. DPP-4 inhibitors are incretin-based therapies that can be used as monotherapy or in combination with other antidiabetes medications to treat T2DM. As monotherapy, DPP-4 inhibitors have demonstrated a modest and comparable glycated hemoglobin-lowering effect. As initial dual therapy with other antidiabetes agents, DPP-4 inhibitors significantly improved glycated hemoglobin when compared with monotherapy arms. Similarly, in triple combinations, DPP-4 inhibitors consistently provided additive glycemic benefits. In patients who were continuing insulin, glycemic parameters were improved with the addition of a DPP-4 inhibitor, and they required less insulin uptitration. In clinical trials, the overall occurrence of adverse events was similar between DPP-4 inhibitor groups and controls, and a low occurrence of hypoglycemia was observed, except when used in combination with a sulfonylurea. A neutral effect on weight was maintained, even in combination with insulin. Similar to outcomes observed in younger patients, DPP-4 inhibitors significantly improved glycemic efficacy in older patients, without increasing the risk for hypoglycemia. Efficacy and safety in patients with renal insufficiency are also documented.

CONCLUSION

DPP-4 inhibitors are therapeutically beneficial for a diverse population of patients with T2DM, including elderly patients, based on demonstrated efficacy, tolerability, and a low risk for hypoglycemia.

Clinical use of dipeptidyl peptidase-4 and sodium-glucose cotransporter 2 inhibitors in combination therapy for type 2 diabetes mellitus

OBJECTIVE

To review the efficacy, safety, and tolerability of combination treatment regimens including a dipeptidyl peptidase-4 (DPP-4) inhibitor and/or sodium-glucose cotransporter 2 (SGLT2) inhibitor for type 2 diabetes mellitus (T2DM).

METHODS

Clinical trials of combination therapies including a DPP-4 and/or SGLT2 inhibitor were identified through a PubMed database search. To be included, studies had to have a primary end point of change from baseline to ≥24 weeks in glycated hemoglobin, include ≥1 other oral antidiabetic drug (OAD), and have randomized more than 200 patients. Results were limited to medications approved by the US Food and Drug Administration at the time of the search (March 2015).

RESULTS

A total of 1534 articles for the DPP-4 inhibitor class and 434 articles for the SGLT2 inhibitor class were retrieved from PubMed. Of these, 33 articles from the DPP-4 inhibitor class and 24 articles from the SGLT2 inhibitor class were included for review. In each study, the addition of a DPP-4 or SGLT2 inhibitor as a second or third agent resulted in improved glycemic control versus comparator arms. Reductions in weight or lack of weight gain were consistently observed, as were low rates of hypoglycemic events, particularly when the combination regimen also included metformin. Overall, the pattern of adverse events observed in combination treatment groups was consistent with the known effects of the individual agents.

CONCLUSION

Combination treatment with a DPP-4 and/or SGLT2 inhibitor is an efficacious option for patients with T2DM starting pharmacological therapy, or for patients who have received treatment but require additional glycemic control. Study findings indicate that the underlying mechanisms of action of DPP-4 inhibitors and SGLT2 inhibitors complement a variety of OADs.

Efficacy of dipeptidyl-peptidase-4 inhibitors and impact on β-cell function in Asian and Caucasian type 2 diabetes mellitus patients: A meta-analysis

BACKGROUND

This work aimed to compare the efficacy of dipeptidyl peptidase-IV (DPP-4) inhibitors and their impact on β-cell function in Asian and Caucasian patients with type 2 diabetes mellitus.

METHODS

Databases were systematically searched and qualifying studies that compared DPP-4 inhibitors with other antidiabetic medications in type 2 diabetes were included.

RESULTS

A total of 68 studies were included in the meta-analysis. Comparison of DPP-4 inhibitors with placebo in Asian patients showed a decrease in glycosylated hemoglobin (HbA1c ) favoring DPP-4 inhibitors (weighted mean difference [WMD], -0.81%; 95% confidence interval [CI], -0.95% to -0.68%; P < 0.001). Comparison of HbA1c changes between Asian and Caucasian patients showed a significant between-group difference of -0.18% (95% CI, -0.32% to -0.04%; P = 0.011) when compared with placebo. In Asian patients, the homeostatic model assessment for β-cell function (HOMA-β) was increased with DPP-4 inhibitors compared with placebo (WMD, 7.90; 95% CI, 4.29 to 11.51; P < 0.001), although to a lesser extent in Caucasian patients. Comparisons between Asian and Caucasian patients showed a significant between-group difference of -4.97 (95% CI, -9.86 to -0.09; P = 0.046) compared with placebo. Body weight increase with DPP-4 inhibitors compared with placebo was comparable in Asian and Caucasian studies (WMD, 0.37 kg and 0.45 kg and 95% CI, 0.04-0.69 and 0.27-0.62, respectively).

CONCLUSIONS

The glucose-lowering efficacy of DPP-4 inhibitors was greater in Asian patients than in Caucasian patients, although the effect on β-cell function was inferior in Asian patients. The effect of DPP-4 inhibitors on insulin resistance and body weight in Asian patients was comparable with that observed in Caucasian patients.

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.

Implications of incretin-based therapies on cardiovascular disease

BACKGROUND

Incretin-based therapies offer another treatment option for patients with type 2 diabetes. Agents that provide glycaemic control in addition to attenuating cardiovascular disease (CVD) risk factors are important for diabetes management. This review will focus on the off-target effects of incretin-based therapies on CVD risk factors [body weight, blood pressure (BP), lipid profile and albuminuria], major adverse cardiovascular events (MACE), heart failure (HF) and beta-cell preservation.

METHODS

A literature search was conducted to identify English-language publications for incretin-based therapies evaluating the following off-target end-points: body weight, BP, lipid profile, albuminuria, MACE, HF and beta-cell function. Randomised controlled trials (RCTs) were prioritised as the primary source of information.

RESULTS

Overall, incretin-based therapies have shown beneficial effects on CVD risk factors, and glucagon-like peptide 1 (GLP-1) receptor agonists appear to have a more pronounced effect compared with dipeptidyl peptidase-4 inhibitors. RCTs are being conducted to determine if these positive effects on CVD risk factors translate to a reduction in MACE. To date, these studies have not shown an increase in MACE. A signal of increased hospitalisations for HF was observed with saxagliptin, warranting continued evaluation and vigilance in high-risk patients. In addition, incretin-based therapies have shown positive effects on measures of beta-cell function supporting their durability in the management of diabetes.

CONCLUSIONS

Incretin-based therapies are an important treatment option for patients with type 2 diabetes, offering beneficial effects on CVD risk factors without increasing MACE.

Determinants of saxagliptin use among patients with type 2 diabetes mellitus treated with oral anti-diabetic drugs

BACKGROUND

The patterns and determinants of saxagliptin use among patients with type 2 diabetes mellitus (T2DM) are unknown in real-world settings. We compared the characteristics of T2DM patients who were new initiators of saxagliptin to those who were new initiators of non-dipeptidyl peptidase-4 (DPP-4) inhibitor oral anti-diabetic drugs (OADs) and identified factors associated with saxagliptin use.

METHODS

We conducted a cross-sectional study within the Clinical Practice Research Datalink (CPRD), The Health Improvement Network (THIN), US Medicare, and the HealthCore Integrated Research Database (HIRD(SM)) across the first 36 months of saxagliptin availability (29 months for US Medicare). Patients were included if they were: 1) ≥18 years old, 2) newly prescribed saxagliptin or a non-DPP-4 inhibitor OAD, and 3) enrolled in their respective database for 180 days. For each saxagliptin initiator, we randomly selected up to ten non-DPP-4 inhibitor OAD initiators matched on age, sex, and geographic region. Conditional logistic regression was used to identify determinants of saxagliptin use.

RESULTS

We identified 64,079 saxagliptin initiators (CPRD: 1,962; THIN: 2,084; US Medicare: 51,976; HIRD(SM): 8,057) and 610,660 non-DPP-4 inhibitor OAD initiators (CPRD: 19,484; THIN: 19,936; US Medicare: 493,432; HIRD(SM): 77,808). Across all four data sources, prior OAD use, hypertension, and hyperlipidemia were associated with saxagliptin use. Saxagliptin initiation was also associated with hemoglobin A1c results >8% within the UK data sources, and a greater number of hemoglobin A1c measurements in the US data sources.

CONCLUSIONS

In these UK and US data sources, initiation of saxagliptin was associated with prior poor glycemic control, prior OAD use, and diagnoses of hypertension and hyperlipidemia.

TRIAL REGISTRATION

ClinicalTrials.gov identifiers NCT01086280 , NCT01086293 , NCT01086319 , NCT01086306 , and NCT01377935.

Dipeptidyl peptidase-4 inhibitors and cardiovascular outcomes: meta-analysis of randomized clinical trials with 55,141 participants

AIMS

The association between glucose lowering in diabetes mellitus and major cardiovascular (CV) outcomes is weak; indeed, some oral hypoglycemic agents are associated with increased CV events. Dipeptidyl peptidase-4 inhibitors (DPP-4 inhibitors) are a new class of oral hypoglycemic agent that may have beneficial CV effects. We undertook a systematic review and meta-analysis to appraise the CV safety and efficacy of DPP-4 inhibitors.

METHODS

Comprehensive search for prospective trials involving DPP-4 inhibitors. Trials included reported at least one of the outcomes examined, recruited minimum 100 patients and minimum follow-up 24 weeks. The risk ratio (RR) was calculated using the Mantel-Haenszel random-effects model for mortality and major cardiovascular (CV) outcomes.

RESULTS

Fifty trials enrolling 55,141 participants were included. Mean follow-up 45.3 weeks. DPP-4 inhibitors compared with all comparators (placebo and active) showed no difference in all-cause mortality (n = 50,982, RR = 1.01, 95% CI 0.91-1.13, P = 0.83), CV mortality (n = 48,151, RR = 0.97, 95% CI 0.85-1.11, P = 0.70), acute coronary syndrome (ACS) (n = 53,034 RR = 0.97, 95% CI 0.87-1.08, P = 0.59), or stroke (n = 42,737, RR = 0.98, 95% CI 0.81-1.18, P = 0.80), and a statistically significant increase in heart failure outcomes (n = 39,953, RR = 1.16, 95% CI 1.01-1.33, P = 0.04).

DISCUSSION

Treatment with DPP-4 inhibitors compared with placebo shows no increase in risk with regards to all-cause mortality, CV mortality, ACS, or stroke, but a statistically significant trend toward increased risk of HF outcomes.

CONCLUSION

These findings suggest no cardiovascular harm (or benefit) with DPP-4 inhibitors; further large-scale CV outcome studies will resolve the issue of excess HF risk.

Cardiometabolic Effects of a New Class of Antidiabetic Agents

PURPOSE

Within the past decade, many new classes of drugs have received approval from the US Food and Drug Administration for treatment of type 2 diabetes mellitus, including glucagon-like peptide-1agonists, dipeptidyl peptidase-4 inhibitors, and the sodium-glucose cotransporter-2 inhibitors. Many trials have been performed, and several more are currently ongoing to evaluate these drugs. This review addresses the broad therapeutic and pleiotropic effects of these drugs. The review also discusses the role of these drugs in the treatment paradigm for type 2 diabetes and identifies patients who would be suitable candidates for treatment with these drugs.

METHODS

In this comprehensive evidence-based review, the following databases were searched from 1990 to the present: PubMed/MEDLINE, Scopus, CINAHL, ClinicalTrials.gov, the World Health Organization International Clinical Trials Registry Portal, and the American Diabetes Association and European Association for the Study of Diabetes abstract databases. Randomized clinical trials (RCTs) were only included for the main therapeutic and cardiovascular (CV) effects of these drug classes. For pleiotropic effects, RCTs were included unless no RCTs exist, in which case other studies as specified in the detailed Methods section were included.

FINDINGS

All 3 drug classes are effective in lowering hemoglobin A1c between 0.4% and 1.4%, depending on the drug class and population selected. These drug classes have beneficial effects on CV risk factors, such as weight, lipids, and blood pressure, in addition to lowering blood glucose levels. The CV tolerability of some drugs has been evaluated and found to be neutral; however, most trials are currently ongoing to assess CV tolerability. There are no concrete guidelines to determine where these drugs fit in the diabetes management paradigm, and there are ongoing trials to determine the best combination drug with metformin.

IMPLICATIONS

These 3 drug classes will potentially increase the armamentarium against hyperglycemia. However, the specific combinations with other antidiabetic drugs and populations that will best benefit from these drugs are still being tested. Future research is also being conducted on the use of glucagon-like peptide-1 receptor agonists and sodium-glucose cotransporter-2 inhibitors in patients with type 1 diabetes.

Efficacy and safety of linagliptin co-administered with low-dose metformin once daily versus high-dose metformin twice daily in treatment-naïve patients with type 2 diabetes: a double-blind randomized trial

Introduction

The aim of this study was to investigate the efficacy and safety of linagliptin + low-dose (LD) metformin once daily versus high-dose (HD) metformin twice daily in treatment-naïve patients with type 2 diabetes.

Methods

Patients (n = 689) were randomized (1:1) to double-blind treatment with linagliptin 5 mg + LD metformin (1000 mg) or HD metformin (2000 mg) for 14 weeks. Metformin was initiated at 500 mg/day and up-titrated within 2 weeks; the dose then remained unchanged. The primary endpoint was change in glycated hemoglobin (HbA1c) from baseline to Week 14 in patients who tolerated a daily metformin dose of ≥1000 mg after 2 weeks.

Results

At Week 14, HbA1c changed from a mean baseline of 8.0% (64 mmol/mol) by −0.99% (−11 mmol/mol) for linagliptin + LD metformin, and −0.98% (−11 mmol/mol) for HD metformin [treatment difference −0.01% (95% confidence interval −0.13, 0.12) (0 mmol/mol), P = 0.8924]. The proportion of patients who achieved HbA1c <7.0% (53 mmol/mol) without occurrence of moderate or severe gastrointestinal (GI) events (including abdominal pain, nausea, vomiting, diarrhea, and decreased appetite) was the same in both groups (51.3% for both). Although the occurrence of moderate or severe GI events was similar, the linagliptin + LD metformin group had fewer mild GI events (18.5% versus 24.3%). The incidence of hypoglycemia was low in both groups.

Conclusion

Linagliptin + LD metformin combination showed similar efficacy and safety to HD metformin. This combination may be an alternative treatment option in patients who may have difficulty tolerating metformin doses >1000 mg/day.

Funding

Boehringer Ingelheim.

Electronic supplementary material

The online version of this article (doi:10.1007/s12325-015-0195-3) contains supplementary material, which is available to authorized users.

Dual add-on therapy in type 2 diabetes poorly controlled with metformin monotherapy: a randomized double-blind trial of saxagliptin plus dapagliflozin addition versus single addition of saxagliptin or dapagliflozin to metformin

OBJECTIVE

This study compared the efficacy and safety of dual add-on of saxagliptin plus dapagliflozin versus saxagliptin and dapagliflozin added on alone in patients with type 2 diabetes poorly controlled with metformin.

RESEARCH DESIGN AND METHODS

This was a double-blind trial in adults with HbA1c ≥8.0% and ≤12.0% (64-108 mmol/mol), randomized to saxagliptin (SAXA) (5 mg/day) plus dapagliflozin (DAPA) (10 mg/day; n = 179), or SAXA (5 mg/day) and placebo (n = 176), or DAPA (10 mg/day) and placebo (n = 179) on background metformin extended release (MET) ≥1,500 mg/day. Primary objective compared changes from baseline in HbA1c with SAXA+DAPA+MET versus SAXA+MET and DAPA+MET.

RESULTS

Patients had a mean baseline HbA1c of 8.9% (74 mmol/mol), diabetes duration of 7.6 years, and a BMI of 32 kg/m(2). At week 24, the adjusted mean change from the baseline HbA1c was -1.5% (-16.1 mmol/mol) with SAXA+DAPA+MET versus -0.9% (-9.6 mmol/mol) with SAXA+MET (difference -0.59% [-6.4 mmol/mol], P < 0.0001) and -1.2% (-13.1 mmol/mol) with DAPA+MET (difference -0.27% [3.0 mmol/mol], P < 0.02). The proportion of patients achieving HbA1c <7% (53 mmol/mol) was 41% with SAXA+DAPA+MET versus 18% with SAXA+MET and 22% with DAPA+MET. Urinary and genital infections occurred in ≤1% of patients receiving SAXA+DAPA+MET. Hypoglycemia was infrequent, with no episodes of major hypoglycemia.

CONCLUSIONS

In this first report of adding a well-tolerated combination of saxagliptin plus dapagliflozin to background metformin therapy in patients poorly controlled with metformin, greater improvements in glycemic control were obtained with triple therapy by the dual addition of saxagliptin and dapagliflozin than dual therapy with the addition of saxagliptin or dapagliflozin alone.

Initial combination of linagliptin and metformin compared with linagliptin monotherapy in patients with newly diagnosed type 2 diabetes and marked hyperglycaemia: a randomized, double-blind, active-controlled, parallel group, multinational clinical trial

AIMS

To evaluate glucose-lowering treatment strategies with linagliptin and metformin in people with newly diagnosed type 2 diabetes and marked hyperglycaemia, a prevalent population for which few dedicated studies of oral antidiabetes drugs have been conducted.

METHODS

A total of 316 patients, with type 2 diabetes diagnosed for ≤12 months and with glycated haemoglobin (HbA1c) concentration in the range 8.5-12.0%, were randomized 1:1 to double-blind, free-combination treatment with linagliptin 5 mg once daily and metformin twice daily (uptitrated to 2000 mg/day maximum) or to linagliptin monotherapy. The primary endpoint was change in HbA1c concentration from baseline at week 24 (per-protocol completers' cohort: n = 245).

RESULTS

The mean (standard deviation) age and HbA1c at baseline were 48.8 (11.0) years and 9.8 (1.1)%, respectively. At week 24, the mean ± standard error (s.e.) HbA1c decreased from baseline by -2.8 ± 0.1% with linagliptin/metformin and -2.0 ± 0.1% with linagliptin; a treatment difference of -0.8% (95% confidence interval -1.1 to -0.5; p <0.0001). Similar results were observed in a sensitivity analysis based on intent-to-treat principles: adjusted mean ± s.e. changes in HbA1c of -2.7 ± 0.1% and -1.8 ± 0.1%, respectively; treatment difference of -0.9% (95% CI -1.3 to -0.6; p <0.0001). A treatment response of HbA1c <7.0% was achieved by 61 and 40% of patients in the linagliptin/metformin and linagliptin groups, respectively. Few patients experienced drug-related adverse events (8.8 and 5.7% of patients in the linagliptin/metformin and linagliptin groups, respectively). Hypoglycaemia occurred in 1.9 and 3.2% of patients in the linagliptin/metformin and linagliptin groups, respectively (no severe episodes). Body weight decreased significantly with the combination therapy (-1.3 kg between-group difference; p =0.0033).

CONCLUSIONS

Linagliptin in initial combination with metformin in patients with newly diagnosed type 2 diabetes and marked hyperglycaemia, an understudied group, elicited significant improvements in glycaemic control with a low incidence of hypoglycaemia, weight gain or other adverse effects. These results support early combination treatment strategies and suggest that newly diagnosed patients with marked hyperglycaemia may be effectively managed with oral, non-insulin therapy.

Saxagliptin efficacy and safety in patients with type 2 diabetes mellitus stratified by cardiovascular disease history and cardiovascular risk factors: analysis of 3 clinical trials

OBJECTIVE

To test the effectiveness and safety of saxagliptin 5 mg/d in patients with type 2 diabetes mellitus (T2DM) with and without history of cardiovascular disease (CVD) or cardiovascular (CV) risk factors.

METHODS

The authors conducted a post hoc analysis of data from 3 randomized studies that compared saxagliptin versus placebo as initial combination therapy with metformin for 24 weeks (N = 648) and versus placebo as an add-on to insulin with and without metformin for 24 weeks (N = 455), and assessed noninferiority to glipizide as an add-on to metformin for 52 weeks (N = 858). Efficacy outcomes were the adjusted mean change from baseline in glycated hemoglobin (HbA1c) level, fasting plasma glucose concentration, and body weight and the proportion of patients achieving an HbA1c level < 7%. Pairwise comparisons were performed in subgroups with 1) history/no history of CVD, 2) ≥ 2 versus 0 to 1 CV risk factors, 3) hypertension/no hypertension, and 4) statin use/no statin use. Adverse events (AE) and hypoglycemia were monitored.

RESULTS

In the initial combination therapy study, reductions in HbA1c level from baseline were greater with saxagliptin versus placebo in all subgroups (difference [saxagliptin - placebo], -0.38% to -0.67%). In the add-on to insulin ± metformin study, differences in adjusted mean change in HbA1c level versus placebo ranged from -0.23% to -0.58% across subgroups. In the noninferiority to glipizide study, adjusted mean changes in HbA1c level were comparable between saxagliptin and glipizide, across subgroups (difference, 0.08%-0.21%). No evidence suggested clinically relevant treatment-by-subgroup interactions in pairwise comparison. Incidences of ≥ 1 AE were comparable across subgroups. Incidences of confirmed hypoglycemia with saxagliptin were 0 in both metformin add-on studies and 1.2% to 7.8% with saxagliptin + insulin ± metformin.

CONCLUSION

In patients with T2DM, saxagliptin 5 mg/d was similarly effective in improving glycemic control, with an AE profile similar to that of placebo, irrespective of CVD history, number of CV risk factors, hypertension, or statin use.

TRIAL REGISTRATION

www.ClinicalTrials.gov identifiers: NCT00327015, NCT00575588, NCT00757588.

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.

Increased plasma DPP4 activity predicts new-onset hypertension in Chinese over a 4-year period: possible associations with inflammation and oxidative stress

To investigate whether increased dipeptidyl peptidase 4 (DPP4) activity predicts new-onset hypertension in Chinese patients. A prospective study was conducted for 1884 adults (804 men/1080 women) aged 18-70 years without hypertension. Participants were examined in 2007 (baseline) and 2011 (follow-up) and circulating DPP4 activity, mannose 6-phosphate receptor (M6P-R) concentration, inflammatory markers and oxidative stress parameters were measured. After a 4-year follow-up, 296 individuals developed hypertension with an incidence of 39 per 1000 patient years. In multiple linear regression analyses, baseline DPP4 activity was an independent predictor of an increase in M6P-R, inflammatory markers and oxidative stress parameters over a 4-year period (all P < 0.01). Cox proportional hazards models revealed that DPP4 activity independently predicted the risk of developing hypertension (relative risk 2.68 (95% confidence interval 1.71-4.21) P < 0.01). Our results indicate that DPP4 activity is an important predictor of hypertension onset in apparently healthy Chinese individuals. This finding may have important implications for understanding the effects of DPP4 in promoting inflammation and oxidative stress in the pathogenesis of hypertension.

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.

Efficacy and safety of saxagliptin as add-on therapy in type 2 diabetes

Combination therapy for type 2 diabetes using agents with complementary mechanisms of action may improve glycemic control to a greater extent than monotherapy and allow the use of lower doses of antihyperglycemic medications. Dipeptidyl peptidase-4 inhibitors, including saxagliptin, are recommended as add-on therapy to metformin and as part of two- or three-drug combinations in patients not meeting individualized glycemic goals with metformin alone or as part of a dual-therapy regimen. This article reviews the efficacy and safety of saxagliptin as an add-on therapy to metformin, glyburide, a thiazolidinedione, or insulin (with or without metformin) and as a component of triple therapy with metformin and a sulfonylurea.

Evidence-based practice use of incretin-based therapy in the natural history of diabetes

The incretin class of anti-hyperglycemic agents, including glucagon-like peptide-1 receptor agonists and dipeptidyl peptidase-inhibitors, is an important addition to the therapeutic armamentarium for the management of appropriate patients with type 2 diabetes mellitus as an adjunct to diet and exercise and/or with the agents metformin, sulfonylureas, thiazolidinediones, or any combination thereof. More recently, US Food and Drug Administration (FDA)-approved indications for incretins were expanded to include use with basal insulin. This review article takes an evidence-based practice approach in discussing the importance of aggressive treatment for diabetes, the principles of incretin physiology and pathophysiology, use of glucagon-like peptide-1 receptor agonists and dipeptidyl peptidase-4 inhibitors, and patient types and contexts where incretin therapy has been found beneficial, from metabolic syndrome to overt diabetes.

Efficacy and safety of dulaglutide monotherapy versus metformin in type 2 diabetes in a randomized controlled trial (AWARD-3)

OBJECTIVE

Compare the efficacy and safety of monotherapy with dulaglutide, a once-weekly GLP-1 receptor agonist, to metformin-treated patients with type 2 diabetes. The primary objective compared dulaglutide 1.5 mg and metformin on change from baseline glycosylated hemoglobin A1c (HbA1c) at 26 weeks.

RESEARCH DESIGN AND METHODS

This 52-week double-blind study randomized patients to subcutaneous dulaglutide 1.5 mg, dulaglutide 0.75 mg, or metformin. Patients (N = 807) had HbA1c ≥6.5% (≥48 mmol/mol) and ≤9.5% (≤80 mmol/mol) with diet and exercise alone or low-dose oral antihyperglycemic medication (OAM) monotherapy; OAMs were discontinued at beginning of lead-in period.

RESULTS

At 26 weeks, changes from baseline HbA1c (least squares [LS] mean ± SE) were: dulaglutide 1.5 mg, -0.78 ± 0.06% (-8.5 ± 0.70 mmol/mol); dulaglutide 0.75 mg, -0.71 ± 0.06% (-7.8 ± 0.70 mmol/mol); and metformin, -0.56 ± 0.06% (-6.1 ± 0.70 mmol/mol). Dulaglutide 1.5 and 0.75 mg were superior to metformin (LS mean difference): -0.22% (-2.4 mmol/mol) and -0.15% (-1.6 mmol/mol) (one-sided P < 0.025, both comparisons), respectively. Greater percentages reached HbA1c targets <7.0% (<53 mmol/mol) and ≤6.5% (≤48 mmol/mol) with dulaglutide 1.5 and 0.75 mg compared with metformin (P < 0.05, all comparisons). No severe hypoglycemia was reported. Compared with metformin, decrease in weight was similar with dulaglutide 1.5 mg and smaller with dulaglutide 0.75 mg. Over 52 weeks, nausea, diarrhea, and vomiting were the most common adverse events; incidences were similar between dulaglutide and metformin.

CONCLUSIONS

Dulaglutide improves glycemic control and is well tolerated as monotherapy in patients with early stage type 2 diabetes.

Efficacy and safety of initial combination therapy with alogliptin plus metformin versus either as monotherapy in drug-naïve patients with type 2 diabetes: a randomized, double-blind, 6-month study

AIM

To evaluate the efficacy and safety of the dipeptidyl peptidase-4 inhibitor alogliptin plus metformin (A + M) initial combination therapy versus either as monotherapy in drug-naïve T2DM patients.

METHODS

This international, randomized, double-blind, placebo-controlled, 26-week study involved T2DM patients with hyperglycaemia (HbA1c 7.5-10.0%) following diet/exercise therapy. Patients (N = 784) received placebo, alogliptin (A, 12.5 mg BID or 25 mg QD), metformin (M, 500 or 1000 mg BID) or A + M (12.5/500 or 12.5/1000 mg BID); placebo, A25 for secondary analyses only.

ENDPOINTS

week 26 changes from baseline in HbA1c (primary), fasting plasma glucose (FPG) and 2-h postprandial glucose (PPG); incidences of clinical response and hyperglycaemic rescue.

RESULTS

Week 26 mean HbA1c reductions from baseline (8.45%) were -1.22 and -1.55% with A + M 12.5/500 and 12.5/1000 versus -0.56, -0.65, and -1.11% with A12.5, M500 and M1000 (p<0.001, A + M vs. component monotherapies). FPG reductions were -1.76 and -2.55 mmol/L with 12.5/500 and 12.5/1000 versus -0.54, -0.64 and -1.78 mmol/L with A12.5, M500 and M1000 (p < 0.05, A + M vs. component monotherapies). Significantly more A + M-treated patients achieved HbA1c < 7% (47.1-59.5% vs. 20.2-34.3% with monotherapy), significantly fewer required hyperglycaemic rescue (2.6-12.3% vs. 10.8-22.9% with monotherapy). A + M caused only mild/moderate hypoglycaemia (1.9-5.3%) and weight loss (0.6-1.2 kg).

CONCLUSIONS

Alogliptin plus metformin initial combination therapy was well tolerated yet more efficacious in controlling glycaemia in drug-naïve T2DM patients than either as monotherapy.

Comparative effectiveness of dipeptidylpeptidase-4 inhibitors in type 2 diabetes: a systematic review and mixed treatment comparison

OBJECTIVE

To compare the safety and efficacy of the dipeptidylpeptidase-4 (DPP-4) inhibitors in patients with type 2 diabetes and inadequate glycemic control.

DESIGN

Systematic review of randomized controlled trials (RCTs), health economic evaluation studies, systematic reviews, and meta-analyses, followed by primary Bayesian mixed treatment comparison meta-analyses (MTCs), and secondary frequentist direct-comparison meta-analyses using a random-effects model. Outcomes were reported as weighted mean change from baseline, or odds ratio (OR) with 95% credible interval.

DATA SOURCES

MEDLINE, MEDLINE In-Process, EMBASE, and BIOSIS via Dialog ProQuest; Cochrane Central Register of Controlled Trials and Cochrane Database of Systematic Reviews via EBSCO; four diabetes and two technical congress abstracts; and health technology assessment organization websites.

ELIGIBILITY CRITERIA

Patients with type 2 diabetes and inadequate glycemic control receiving any pharmacological anti-diabetic treatment.

DATA EXTRACTION AND ANALYSIS

Title/abstracts were reviewed for eligibility, followed by full-text review of publications remaining after first pass. A three-person team filtered articles and an independent reviewer checked a random selection (10%) of filtered articles. Data extraction and quality assessment of studies were also independently reviewed. Five DPP-4 inhibitors (alogliptin, linagliptin, saxagliptin, sitagliptin, and vildagliptin) were compared via meta-analysis (where data were available) as monotherapy, dual therapy (plus metformin, sulfonylurea, pioglitazone, or insulin), and triple therapy (plus metformin/sulfonylurea).

RESULTS

The review identified 6,601 articles; 163 met inclusion criteria and 85 publications from 83 RCTs contained sufficient or appropriate data for analysis. MTCs demonstrated no differences between DPP-4 inhibitors in mean change from baseline in glycosylated hemoglobin (HbA1c) or body weight, or the proportions of patients achieving HbA1c <7% or experiencing a hypoglycemic event, apart from in patients on alogliptin plus metformin, who achieved HbA1c <7% more frequently than those treated with saxagliptin plus metformin [OR 6.41 (95% CI 3.15-11.98) versus 2.17 (95% CI 1.56-2.95)].

CONCLUSIONS

This systematic review and MTC showed similar efficacy and safety for DPP-4 inhibitors as treatment for type 2 diabetes, either as monotherapy or combination therapy.

Saxagliptin versus glipizide as add-on therapy to metformin: assessment of hypoglycemia

OBJECTIVE

To compare characteristics of hypoglycemic episodes in patients with type 2 diabetes receiving saxagliptin or glipizide add-on therapy to metformin.

PATIENTS AND METHODS

This was a post hoc analysis of an international, randomized, parallel-group, double-blind, active-controlled, phase 3 trial. The 52-week trial and 52-week extension were conducted from December 2007 to August 2010. Patients aged ≥18 years with glycated hemoglobin (HbA1c) >6.5% to 10.0% receiving stable metformin doses (≥1500 mg/d) were randomized 1:1 to add-on therapy with saxagliptin 5 mg/d or glipizide 5 to 20 mg/d (titrated to optimal effect or highest tolerable dose during the initial 18 weeks). Hypoglycemic episodes were recorded in patient diaries. Confirmed hypoglycemic events were defined as fingerstick glucose ≤50 mg/dL (≤2.8 mmol/L) with associated symptoms.

RESULTS

Of 858 patients randomized, 428 received saxagliptin + metformin, and 430 received glipizide + metformin. Saxagliptin was noninferior to glipizide in lowering HbA1c. Hypoglycemia with saxagliptin + metformin and glipizide + metformin was reported by 15 (24 events) and 165 (896 events) patients, respectively, through week 104. The mean (SD) number of hypoglycemic events per patient reporting hypoglycemia was lower with saxagliptin + metformin versus glipizide + metformin through weeks 52 (1.5 [SD 0.88] vs 4.8 [SD 4.9], respectively) and 104 (1.6 [SD 0.99] vs 5.4 [SD 5.8]). Most patients receiving glipizide + metformin with hypoglycemia had multiple events (124/165 patients [75%]). Confirmed hypoglycemia, major events, and severe events occurred only with glipizide + metformin. Time to first hypoglycemic event was shorter with glipizide versus saxagliptin. Limitations of this analysis include its post hoc nature, a high rate of study discontinuation, and exclusion of patients with serious comorbidities and complications.

CONCLUSION

Saxagliptin + metformin was associated with fewer patients reporting hypoglycemia and fewer and less severe hypoglycemic events in those experiencing hypoglycemia compared with glipizide + metformin. ClinicalTrials.gov registration number: NCT00575588.

A randomized controlled trial of the efficacy and safety of saxagliptin as add-on therapy in patients with type 2 diabetes and inadequate glycaemic control on metformin plus a sulphonylurea

AIMS

To evaluate the efficacy and safety of saxagliptin as add-on therapy in adults with type 2 diabetes with inadequate glycaemic control on metformin plus a sulphonylurea.

METHODS

In this 24-week, multicentre, randomized, parallel-group, double-blind study, outpatients aged ≥18 years with type 2 diabetes, body mass index ≤40 kg/m(2) and inadequate glycaemic control, received saxagliptin 5 mg or placebo once-daily added to background medication consisting of a stable maximum tolerated dose of metformin plus a sulphonylurea. The primary end point was change in glycated haemoglobin (HbA1c) from baseline to week 24. Safety and tolerability assessments included adverse events (AEs), hypoglycaemia and body weight.

RESULTS

A total of 257 patients were randomized, treated and included in the safety analysis (saxagliptin, n = 129; placebo, n = 128); 255 were included in the efficacy analysis (saxagliptin, n = 127; placebo, n = 128). HbA1c reduction was greater with saxagliptin versus placebo [between-group difference in adjusted mean change from baseline, -0.66%; 95% confidence interval (CI), -0.86 to -0.47 (7 mmol/mol, -9.4 to -5.1); p < 0.0001]. The proportion of patients with ≥1 AE was 62.8% with saxagliptin and 71.7% with placebo. In the saxagliptin and placebo groups, rates of reported hypoglycaemia were 10.1 and 6.3%, respectively, and rates of confirmed hypoglycaemia (symptoms + glucose < 2.8 mmol/l) were 1.6 and 0%. Mean change in body weight was 0.2 kg for saxagliptin and -0.6 kg for placebo (p = 0.0272).

CONCLUSION

Addition of saxagliptin 5 mg/day in patients inadequately controlled on metformin and sulphonylurea effectively improved glycaemic control and was well tolerated.

Incorporating incretin-based therapies into clinical practice for patients with type 2 diabetes

Background

Effective, evidence-based management of type 2 diabetes (T2D) requires the integration of the best available evidence with clinical experience and patient preferences.

Methods

Studies published from 2000 to 2012 evaluating glucagon-like peptide-1 receptor agonists (GLP-1RAs) or dipeptidyl peptidase-4 inhibitors (DPP-4 inhibitors) were identified using PubMed. The author contextualized the study findings with his clinical experience.

Results

Incretin-based therapy targets multiple dysfunctional organs in T2D. Injectable GLP-1RAs provide substantial glycemic control and weight reduction; while oral DPP-4 inhibitors provide moderate glycemic control and weight neutrality. Both classes are effective, well tolerated, and associated with a low incidence of hypoglycemia when used alone or in combination with other antidiabetes agents. GLP-1RAs are associated with transient nausea and, like DPP-4 inhibitors, rare pancreatitis.

Conclusion

Data indicate and clinical experience confirms that incretins are well tolerated in appropriate patients and provide sustained glycemic control and weight loss or weight neutrality throughout T2D progression.

Electronic supplementary material

The online version of this article (doi:10.1007/s12325-014-0100-5) contains supplementary material, which is available to authorized users.

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.

Combination therapy of dipeptidyl peptidase-4 inhibitors and metformin in type 2 diabetes: rationale and evidence

The main pathogenesis of type 2 diabetes mellitus (T2DM) includes insulin resistance and pancreatic islet dysfunction. Metformin, which attenuates insulin resistance, has been recommended as the first-line antidiabetic medication. Dipeptidyl peptidase-4 (DPP-4) inhibitors are novel oral hypoglycaemic agents that protect glucagon-like peptide-1 (GLP-1) from degradation, maintain the bioactivity of endogenous GLP-1, and thus improve islet dysfunction. Results from clinical trials have shown that the combination therapy of DPP-4 inhibitors and metformin [as an add-on, an initial combination or a fixed-dose combination (FDC)] provides excellent efficacy and safety in patients with T2DM. Moreover, recent studies have suggested that metformin enhances the biological effect of GLP-1 by increasing GLP-1 secretion, suppressing activity of DPP-4 and upregulating the expression of GLP-1 receptor in pancreatic β-cells. Conversely, DPP-4 inhibitors have a favourable effect on insulin sensitivity in patients with T2DM. Therefore, the combination of DPP-4 inhibitors and metformin provides an additive or even synergistic effect on metabolic control in patients with T2DM. This article provides an overview of clinical evidence and discusses the rationale for the combination therapy of DPP-4 inhibitors and metformin.

Systematic review and meta-analysis of efficacy and safety of combinational therapy with metformin and dipeptidyl peptidase-4 inhibitors

Combinational therapies are often required in the management of type 2 diabetes mellitus (T2DM). Among the important candidates, dipeptidyl peptidase-4 inhibitors (DPPIs) and metformin combination (DPPI-MET) have shown promising endeavors. In order to examine the efficacy and safety of such a combination therapy in T2DM patients finding inadequate control with metformin, this systematic review and meta-analysis has been conducted. Literature search was made in multiple electronic databases. Inclusion criteria included; RCTs examining the efficacy and safety of DPPI-MET against placebo-MET or MET-only groups of T2DM patients by observing changes in disease endpoints including HbA1c and FPG, and the length of trial be at least 12 weeks. Mean differences based meta-analyses were performed and heterogeneity assessment was carried out. Nineteen studies were selected and included in the meta-analyses. DPPI-MET significantly improved all disease endpoints and the difference could be noticed up to 2 years in the majority of outcome measures. In comparison with PBO-MET, the DPPI-MET combinational therapy resulted in the percent HbA1c changes from baseline with a mean difference [95% CI] of −0.77 [−0.86, −0.69] in 3-month (P < 0.00001), −0.67 [−0.76, −0.59] in 6-month (P < 0.00001), −0.67 [−0.88, −0.47] in 1-year (P < 0.00001) and −0.36 [−0.53, −0.20] in 2-year trials (P < 0.0003). Reduction in body weight and safety profile in the treated and control groups were not different. A combinational therapy with DPPI and metformin significantly improves diabetes clinical indicators and this effect has been observed for up to 2 years herein. Safety and tolerability of DPPI-MET combination have been found well-manageable with a very similar adverse event profile in both treated and control groups.

Efficacy and safety of dipeptidyl peptidase-4 inhibitors and metformin as initial combination therapy and as monotherapy in patients with type 2 diabetes mellitus: a meta-analysis

AIMS

This meta-analysis was performed to provide an update on the efficacy and safety of dipeptidyl peptidase-4 (DPP-4) inhibitors and metformin as initial combination therapy and as monotherapy in patients with type 2 diabetes mellitus (T2DM).

METHODS

We conducted a search on MEDLINE, Embase and Cochrane Collaborative database for randomized controlled trials (RCTs) of DPP-4 inhibitors and metformin as initial combination therapy or as monotherapy in patients with T2DM by the end of December 2012, using the key words 'alogliptin', 'dutogliptin', 'linagliptin', 'saxagliptin', 'sitagliptin', 'vildagliptin' and 'metformin'. RCTs were selected for meta-analysis if (1) they were RCTs comparing DPP-4 inhibitors plus metformin as initial combination therapy or DPP-4 inhibitor monotherapy to metformin monotherapy, (2) duration of treatment was ≥12 weeks and (3) reported data on haemoglobin A1c (HbA1c) change, fasting plasma glucose (FPG) change, weight change, adverse cardiovascular (CV) events, hypoglycaemia or gastrointestinal adverse events (AEs).

RESULTS

A total of eight RCTs were included. Compared with metformin monotherapy, DPP-4 inhibitors monotherapy was associated with lower reduction in HbA1c level [weighted mean differences (MD) = 0.28, 95% confidence intervals (CIs) (0.17, 0.40), p < 0.00001], lower reduction in FPG level [MD = 0.81, 95% CI(0.60, 1.02), p <0.00001], lower weight loss [MD = 1.51, 95% CI (0.89, 2.13), p < 0.00001], but lower risk of adverse CV events [risk ratio (RR) = 0.36, 95% CI (0.15, 0.85), p = 0.02], lower risk of hypoglycaemia [RR = 0.44, 95% CI (0.27, 0.72), p = 0.001] and lower risk of gastrointestinal AEs [RR = 0.63, 95% CI(0.55, 0.70), p <0.00001]. Compared with metformin monotherapy, DPP-4 inhibitors plus metformin as initial combination therapy was associated with higher reduction in HbA1c level [MD = -0.49, 95% CI (-0.57, -0.40), p < 0.00001], higher reduction in FPG level [MD = -0.80, 95% CI (-0.87, -0.74), p < 0.00001], lower weight loss [MD = 0.44, 95% CI (0.22, 0.67), p = 0.0001]; but was not associated with a further reduction in adverse CV events [RR=0.54, 95% CI (0.25, 1.19), p = 0.13], nor the higher risk of hypoglycaemia [RR = 1.04, 95% CI (0.72, 1.50), p = 0.82], nor the prolonged risk of gastrointestinal AEs [RR = 0.98, 95% CI (0.88, 1.10), p = 0.77].

CONCLUSIONS

DPP-4 inhibitors, which are safe and effective in controlling the blood glucose, may possibly decrease the risk of CV events in patients with T2DM. It could be a credible alternative for T2DM patients who, for some reason, cannot use metformin, or are in high risk of CV exposure. High-quality, large sample and long-term follow-up clinical trails are needed to confirm the long-term conclusions.

Assessment of pancreatic β-cell function: review of methods and clinical applications

Type 2 diabetes mellitus (T2DM) is characterized by a progressive failure of pancreatic β-cell function (BCF) with insulin resistance. Once insulin over-secretion can no longer compensate for the degree of insulin resistance, hyperglycemia becomes clinically significant and deterioration of residual β-cell reserve accelerates. This pathophysiology has important therapeutic implications. Ideally, therapy should address the underlying pathology and should be started early along the spectrum of decreasing glucose tolerance in order to prevent or slow β-cell failure and reverse insulin resistance. The development of an optimal treatment strategy for each patient requires accurate diagnostic tools for evaluating the underlying state of glucose tolerance. This review focuses on the most widely used methods for measuring BCF within the context of insulin resistance and includes examples of their use in prediabetes and T2DM, with an emphasis on the most recent therapeutic options (dipeptidyl peptidase-4 inhibitors and glucagon-like peptide-1 receptor agonists). Methods of BCF measurement include the homeostasis model assessment (HOMA); oral glucose tolerance tests, intravenous glucose tolerance tests (IVGTT), and meal tolerance tests; and the hyperglycemic clamp procedure. To provide a meaningful evaluation of BCF, it is necessary to interpret all observations within the context of insulin resistance. Therefore, this review also discusses methods utilized to quantitate insulin-dependent glucose metabolism, such as the IVGTT and the euglycemic-hyperinsulinemic clamp procedures. In addition, an example is presented of a mathematical modeling approach that can use data from BCF measurements to develop a better understanding of BCF behavior and the overall status of glucose tolerance.

Incretin-based therapies: focus on effects beyond glycemic control alone

Type 2 diabetes is associated with a high prevalence of comorbidities resulting from hypertension, dyslipidemia, and hyperglycemia. Inadequate management of these risk factors will eventually result in detrimental health consequences. Thus, the effect of a drug on factors such as weight, cardiovascular (CV) risk factors, and adherence is important to consider. A review was undertaken of the recent medical literature describing the extraglycemic characteristics of the two classes of incretin-based therapies-glucagon-like peptide-1 receptor agonists (GLP-1RA) and dipeptidyl peptidase-4 (DPP-4) inhibitors. PubMed searches were performed to identify published data on incretin therapies that describe their effects on CV risk factors, CV events, and factors related to medication adherence. The maintenance or loss of weight associated with the use of GLP-1RAs and DPP-4 inhibitors is well described in the medical literature. These agents also appear to be associated with a modest decrease in blood pressure and a reduced risk of CV events. In addition, several characteristics of incretin therapies may improve rates of medication adherence, such as generally favorable tolerability profiles (particularly with DPP-4 inhibitors), the availability of formulations that simplify treatment regimens, and a low risk for hypoglycemia. The literature on incretin therapies describes a number of clinical characteristics that are relevant to the management of extraglycemic risk factors. As part of a holistic treatment strategy, these properties constitute important considerations for tailoring therapy to individual patients with type 2 diabetes.

Long-term 4-year safety of saxagliptin in drug-naive and metformin-treated patients with Type 2 diabetes

AIMS

To evaluate the safety of saxagliptin ± metformin over 4 years in patients with Type 2 diabetes mellitus.

METHODS

Drug-naive (n = 401; study 11) or metformin-treated (n = 743; study 14) adults with HbA(1c) of 53-86 mmol/mol (7.0-10%) were enrolled in two randomized, placebo-controlled, double-blind trials of saxagliptin 2.5, 5 or 10 mg/day. Patients rescued during or completing 24 weeks of treatment could continue in a 42-month long-term blinded phase, for which the primary goal was assessment of safety and tolerability. Between-group efficacy was not evaluated in the long-term phase of study 11. Time to rescue or discontinuation because of inadequate glycaemic control, change from baseline in HbA(1c) and percentages of patients achieving HbA(1c) < 53 mmol/mol (< 7.0%) were assessed in study 14.

RESULTS

No new safety findings were noted during the long-term phase. Most adverse events were mild or moderate, with slightly greater frequency of upper respiratory infections with saxagliptin. Hypoglycaemic event rates were similar with saxagliptin and placebo. In study 14, time to rescue or discontinuation because of inadequate glycaemic control was longer with saxagliptin plus metformin than for placebo plus metformin. From baseline to week 154, HbA(1c) decreased with saxagliptin but increased with placebo.

CONCLUSION

Saxagliptin monotherapy or add-on to metformin is generally safe and well tolerated, with no increased risk of hypoglycaemia, for up to 4 years.

Bioequivalence of saxagliptin/metformin immediate release (IR) fixed-dose combination tablets and single-component saxagliptin and metformin IR tablets in healthy adult subjects

BACKGROUND

As compared with individual tablets, saxagliptin/metformin immediate release (IR) fixed-dose combination (FDC) tablets offer the potential for increased convenience, compliance, and adherence for patients requiring combination therapy.

OBJECTIVES

Two bioequivalence studies assessed the fed-state and the fasted-state bioequivalence of saxagliptin/metformin IR 2.5 mg/500 mg FDC (study 1) and saxagliptin/metformin IR 2.5 mg/1,000 mg FDC (study 2) relative to the same dosage strengths of the individual component tablets [saxagliptin (Onglyza™) and metformin IR (Glucophage(®))] administered concurrently.

STUDY DESIGNS

These were randomized, open-label, single-dose, four-period, four-treatment, crossover studies in healthy subjects (n = 24 in each study). The treatments in study 1 were a saxagliptin/metformin IR 2.5 mg/500 mg FDC tablet in the fed and fasted states on separate occasions, and saxagliptin 2.5 mg and metformin IR 500 mg tablets co-administered in the fed state and fasted states on separate occasions. The treatments in study 2 were a saxagliptin/metformin IR 2.5 mg/1,000 mg FDC tablet in the fed and fasted states on separate occasions, and saxagliptin 2.5 mg and metformin IR 1,000 mg co-administered in the fed state and fasted states on separate occasions. The pharmacokinetics, safety, and tolerability of each treatment were evaluated.

RESULTS

For both studies, saxagliptin and metformin in the FDCs were bioequivalent to the individual components in both the fed and the fasted states as the limits of the 90 % confidence interval of the ratio of adjusted geometric means for all key pharmacokinetic parameters were contained within the predefined 0.800 to 1.250 bioequivalence criteria. Co-administration of saxagliptin and metformin IR was generally safe and well tolerated as the FDCs or as individual tablets.

CONCLUSIONS

Saxagliptin/metformin IR 2.5 mg/500 mg and saxagliptin/metformin IR 2.5 mg/1,000 mg FDCs were bioequivalent to individual tablets of saxagliptin and metformin of the same strengths in both the fed and the fasted states. No unexpected safety findings were observed with saxagliptin/metformin IR administration. The tolerability of the FDC of saxagliptin/metformin IR was comparable to that of the co-administered individual components. These results indicate that the safety and efficacy profile of co-administration of saxagliptin and metformin can be extended to the saxagliptin/metformin IR FDC tablets.