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

Bone Health in Patients With Type 2 Diabetes

The association between type 2 diabetes mellitus (T2DM) and skeletal fragility is complex, with effects on bone at the cellular, molecular, and biomechanical levels. As a result, people with T2DM, compared to those without, are at increased risk of fracture, despite often having preserved bone mineral density (BMD) on dual-energy x-ray absorptiometry (DXA). Maladaptive skeletal loading and changes in bone architecture (particularly cortical porosity and low cortical volumes, the hallmark of diabetic osteopathy) are not apparent on routine DXA. Alternative imaging modalities, including quantitative computed tomography and trabecular bone score, allow for noninvasive visualization of cortical and trabecular compartments and may be useful in identifying those at risk for fractures. Current fracture risk calculators underestimate fracture risk in T2DM, partly due to their reliance on BMD. As a result, individuals with T2DM, who are at high risk of fracture, may be overlooked for commencement of osteoporosis therapy. Rather, management of skeletal health in T2DM should include consideration of treatment initiation at lower BMD thresholds, the use of adjusted fracture risk calculators, and consideration of metabolic and nonskeletal risk factors. Antidiabetic medications have differing effects on the skeleton and treatment choice should consider the bone impacts in those at risk for fracture. T2DM poses a unique challenge when it comes to assessing bone health and fracture risk. This article discusses the clinical burden and presentation of skeletal disease in T2DM. Two clinical cases are presented to illustrate a clinical approach in assessing and managing fracture risk in these patients.

Assessment and treatment of osteoporosis and fractures in type 2 diabetes

There is substantial, and growing, evidence that type 2 diabetes (T2D) is associated with skeletal fragility, despite often preserved bone mineral density. As post-fracture outcomes, including mortality, are worse in people with T2D, bone management should be carefully considered in this highly vulnerable group. However, current fracture risk calculators inadequately predict fracture risk in T2D, and dedicated randomised controlled trials identifying optimal management in patients with T2D are lacking, raising questions about the ideal assessment and treatment of bone health in these people. We synthesise the current literature on evaluating bone measurements in T2D and summarise the evidence for safety and efficacy of both T2D and anti-osteoporosis medications in relation to bone health in these patients.

The Multiple Biological Functions of Dipeptidyl Peptidase-4 in Bone Metabolism

Dipeptidyl peptidase-4 (DPP4) is a ubiquitously occurring protease involved in various physiological and pathological processes ranging from glucose homeostasis, immunoregulation, inflammation to tumorigenesis. Recently, the benefits of DPP4 inhibitors as novel hypoglycemic agents on bone metabolism have attracted extensive attraction in many studies, indicating that DPP4 inhibitors may regulate bone homeostasis. The effects of DPP4 on bone metabolism are still unclear. This paper thoroughly reviews the potential mechanisms of DPP4 for interaction with adipokines, bone cells, bone immune cells, and cytokines in skeleton system. This literature review shows that the increased DPP4 activity may indirectly promote bone resorption and inhibit bone formation, increasing the risk of osteoporosis. Thus, bone metabolic balance can be improved by decreasing DPP4 activities. The substantial evidence collected and analyzed in this review supports this implication.

Angioedema associated with dipeptidyl peptidase-IV inhibitors

Background

Dipeptidyl peptidase-IV (DPP-IV) inhibitors, also known as gliptins, are a class of oral antidiabetic agents. Postmarketing reports have documented the occurrence of angioedema in patients treated with gliptins and it was found that these drugs increased the risk of angioedema in patients concurrently treated with angiotensin-converting enzyme inhibitors (ACEIs). The aim of this manuscript is to provide an overview of the risk of angioedema associated with gliptins.

Methods

The keywords used for the literature search in the PubMed database included “angioedema” and “dipeptidyl peptidase”, “gliptins”, or the name of each DPP-IV inhibitor. Articles in English published up to December 2020 were taken into consideration.

Results

The available data appear to rule out a higher risk of angioedema associated with gliptin monotherapy and have revealed an increased susceptibility in patients simultaneously treated with gliptins and ACEIs. However, one single multicenter phase IV trial and case reports, even if very limited in number, have shown that angioedema can also occur during treatment with DPP-IV inhibitors without the concomitant use of ACEIs. The involvement of other drugs and drug interactions has occasionally been suggested. In a few patients, deficiency of enzymes involved in bradykinin catabolism was detected and this finding can constitute a risk factor for angioedema exacerbated by treatment with DPP-IV inhibitors.

Conclusions

This risk of angioedema associated with the use of gliptins has mostly been related to the concurrent administration of ACEIs, and has been considered rare, but it might be underestimated and underreported. The role of additional risk factors or drug interactions deserves further investigations. Caution should be taken when considering the use of DPP-IV inhibitors in patients treated with ACEIs or presenting with other known risk factors for angioedema.

Update on: effects of anti-diabetic drugs on bone metabolism

INTRODUCTION

Preclinical, clinical, and population-based studies have provided evidence that anti-diabetic drugs affect bone metabolism and may affect the risk of fracture in diabetic patients.

AREAS COVERED

An overview of the skeletal effects of anti-diabetic drugs used in type 2 diabetes is provided. Searches on AdisInsight, PubMed, and Medline databases were conducted up to 1^st July 2020. The latest evidence from randomized clinical trials and population-based studies on the skeletal safety of the most recent drugs (DPP-4i, GLP-1RA, and SGLT-2i) is provided.

EXPERT OPINION

Diabetic patients present with a higher risk of fracture for a given bone mineral density suggesting a role of bone quality in the etiology of diabetic fracture. Bone quality is difficult to assess in human clinical practice and the use of preclinical models provides valuable information on diabetic bone alterations. As several links have been established between bone and energy homeostasis, it is interesting to study the safety of anti-diabetic drugs on the skeleton. So far, evidence for the newest molecules suggests a neutral fracture risk, but further studies, especially in different types of patient populations (patients at risk or with history of cardiovascular disease, renal impairment, neuropathy) are required to fully appreciate this matter.

Dipeptidyl peptidase 4 inhibitors in the treatment of type 2 diabetes mellitus

Dipeptidyl peptidase 4 inhibitors (DPP4i) have been available for treating type 2 diabetes mellitus since 2006. Although they are a diverse group, DPP4i are all small, orally available molecules that interact with the catalytic site of DPP4 without disturbing any of its other known functions, including its effects on the immune system. DPP4i have no intrinsic glucose-lowering activity, so their efficacy as anti-diabetic agents is related directly to their ability to inhibit DPP4 activity and is mediated through the effects of the substrates they protect. Of these, the incretin hormone, glucagon-like peptide 1, is probably the most important. As the effects of glucagon-like peptide 1 are glucose-dependent, the risk of hypoglycaemia with DPP4i is low. Class effects, which are directly related to the mechanism of action, are common to all DPP4i; these include their overall good safety profile and tolerability, as well as their efficacy in improving glycaemic control, but also, potentially, a small increased risk of acute pancreatitis. Compound-specific effects are those related to their differing chemistries and/or pharmacokinetic profiles. These compound-specific effects could affect the way in which individual DPP4i are used therapeutically and potentially explain off-target adverse effects, such as hospitalization for heart failure, which is seen only with one DPP4i. Overall, DPP4i have a favourable therapeutic profile and are safe and effective in the majority of patients with type 2 diabetes mellitus.

Risk of cancer in patients treated with dipeptidyl peptidase-4 inhibitors: an extensive meta-analysis of randomized controlled trials

AIMS

Observational studies and meta-analyses of randomized trials on dipeptidyl peptidase-4 inhibitors (DPP4i) reported discordant results on the risk of malignancies with this class of drugs. Aim of the present meta-analysis is the assessment of the effect of DPP4i treatment on the incidence of different types of cancer, collecting all available evidence from randomized controlled trials.

METHODS

An extensive MEDLINE, EMBASE, and Cochrane database search for sitagliptin or vildagliptin or omarigliptin or saxagliptin or alogliptin or trelagliptin or anagliptin or linagliptin or gemigliptin or evogliptin or teneligliptin was performed up to September 30th, 2019. All trials performed on type 2 diabetes, with duration ≥ 24 weeks, and comparing of DPP4i with placebo or active drugs were collected. The study has been registered on PROSPERO (#153344). Mantel-Haenszel odds ratio (MH-OR) with 95% confidence interval (95% CI) was calculated for all outcomes.

RESULTS

A total of 157 eligible trials were identified. DPP-4i were not associated with an increased risk of overall cancer (MH-OR 0.93 [0.86, 1.00]; p = 0.07), with no significant differences across individual molecules of the class. When compared with placebo/none, a lower risk of cancer with DPP-4i was observed in placebo-controlled trials (MH-OR 0.90 [0.82, 0.99], p = 0.030), whereas no significant differences have been detected with any other comparators. DPP-4i was associated with a significant reduction in colorectal cancer (MH-OR 0.70 [0.53, 0.94], p = 0.020).

CONCLUSIONS

Available data do not support the hypothesis of an association of DPP4i treatment with malignancies, with a possible beneficial effect for colon-rectal cancer.

Risk of Fractures Associated with Dipeptidyl Peptidase-4 Inhibitor Treatment: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

INTRODUCTION

More and more studies suggest that type 2 diabetes mellitus (T2DM) can lead to an increased fracture risk. Some previous clinical studies and experimental data have shown that some antidiabetic drugs can increase or decrease the incidence of fractures.

METHODS

We searched Medline, Embase, Cochrane Library, and the ClinicalTrials.gov website ( https://www.clinicaltrials.gov ) for published or unpublished randomized controlled trials (RCTs) from inception through 2 December 2018 to compare the effects of dipeptidyl peptidase-4 (DDP-4) inhibitors with active control drugs or placebo in T2DM patients. All RCTs had a duration of at least 12 weeks, and the ultimate measure was whether a fracture occurs or not. We calculated odds ratios and their 95% confidence intervals by the fixed effect Mantel-Haenszel model. Publication bias was investigated firstly through visual observation of funnel plot asymmetry and then through Begg's test or Egger's test. The Cochrane bias risk tools were used to assess the quality of included studies.

RESULTS

Eighty-seven eligible RCTs were included in this study. Of 93,772 participants, 49,270 patients received therapy and 44,502 were control patients. Five kinds of DDP-4 inhibitors were included: sitagliptin, saxagliptin, alogliptin, linagliptin and vildagliptin. There were 676 fractures in the DDP-4 inhibitor treatment group and 646 in the control group. The median average glycosylated hemoglobin level was 8.2%. DDP-4 inhibitor treatment did not seem to influence the fracture risk, no matter whether compared with placebo or active comparators in T2DM patients (Mantel-Haenszel odds ratio (MH-OR) = 1.01, 95% CI 0.90-1.12, P = 0.92). After three subgroup analyses which were defined by drug type, control regimen and duration, the results were still stable.

CONCLUSION

This systematic review and meta-analysis shows that DDP-4 inhibitors do not affect the fracture risk when compared with antidiabetic drugs or placebo in T2DM patients.

Diabetes pharmacotherapy and effects on the musculoskeletal system

Persons with type 1 or type 2 diabetes have a significantly higher fracture risk than age-matched persons without diabetes, attributed to disease-specific deficits in the microarchitecture and material properties of bone tissue. Therefore, independent effects of diabetes drugs on skeletal integrity are vitally important. Studies of incretin-based therapies have shown divergent effects of different agents on fracture risk, including detrimental, beneficial, and neutral effects. The sulfonylurea class of drugs, owing to its hypoglycemic potential, is thought to amplify the risk of fall-related fractures, particularly in the elderly. Other agents such as the biguanides may, in fact, be osteo-anabolic. In contrast, despite similarly expected anabolic properties of insulin, data suggests that insulin pharmacotherapy itself, particularly in type 2 diabetes, may be a risk factor for fracture, negatively associated with determinants of bone quality and bone strength. Finally, sodium-dependent glucose co-transporter 2 inhibitors have been associated with an increased risk of atypical fractures in select populations, and possibly with an increase in lower extremity amputation with specific SGLT2I drugs. The role of skeletal muscle, as a potential mediator and determinant of bone quality, is also a relevant area of exploration. Currently, data regarding the impact of glucose lowering medications on diabetes-related muscle atrophy is more limited, although preclinical studies suggest that various hypoglycemic agents may have either aggravating (sulfonylureas, glinides) or repairing (thiazolidinediones, biguanides, incretins) effects on skeletal muscle atrophy, thereby influencing bone quality. Hence, the therapeutic efficacy of each hypoglycemic agent must also be evaluated in light of its impact, alone or in combination, on musculoskeletal health, when determining an individualized treatment approach. Moreover, the effect of newer medications (potentially seeking expanded clinical indication into the pediatric age range) on the growing skeleton is largely unknown. Herein, we review the available literature regarding effects of diabetes pharmacotherapy, by drug class and/or by clinical indication, on the musculoskeletal health of persons with diabetes.

Physiology and Pharmacology of DPP-4 in Glucose Homeostasis and the Treatment of Type 2 Diabetes

Dipeptidyl peptidase-4 (DPP-4), also known as the T-cell antigen CD26, is a multi-functional protein which, besides its catalytic activity, also functions as a binding protein and a ligand for a variety of extracellular molecules. It is an integral membrane protein expressed on cells throughout the body, but is also shed from the membrane and circulates as a soluble protein in the plasma. A large number of bioactive molecules can be cleaved by DPP-4 in vitro, but only a few of these have been demonstrated to be physiological substrates. One of these is the incretin hormone, glucagon-like peptide-1 (GLP-1), which plays an important role in the maintenance of normal glucose homeostasis, and DPP-4 has been shown to be the key enzyme regulating its biological activity. This pathway has been targeted pharmacologically through the development of DPP-4 inhibitors, and these are now a successful class of anti-hyperglycaemic agents used to treat type 2 diabetes (T2DM). DPP-4 may additionally influence metabolic control via its proteolytic effect on other regulatory peptides, but it has also been reported to affect insulin sensitivity, potentially mediated through its non-enzymatic interactions with other membrane proteins. Given that altered expression and activity of DPP-4 are associated with increasing body mass index and hyperglycaemia, DPP-4 has been proposed to play a role in linking obesity and the pathogenesis of T2DM by functioning as a local mediator of inflammation and insulin resistance in adipose and hepatic tissue. As well as these broader systemic effects, it has also been suggested that DPP-4 may be able to modulate β-cell function as part of a paracrine system involving GLP-1 produced locally within the pancreatic islets. However, while it is evident that DPP-4 has the potential to influence glycaemic control, its overall significance for the normal physiological regulation of glucose homeostasis in humans and its role in the pathogenesis of metabolic disease remain to be established.

Safety and tolerability of dapagliflozin, saxagliptin and metformin in combination: Post-hoc analysis of concomitant add-on versus sequential add-on to metformin and of triple versus dual therapy with metformin

The safety of triple oral therapy with dapagliflozin plus saxagliptin plus metformin versus dual therapy with dapagliflozin or saxagliptin plus metformin was compared in a post-hoc analysis of 3 randomized trials of sequential or concomitant add-on of dapagliflozin and saxagliptin to metformin. In the concomitant add-on trial, patients with type 2 diabetes on stable metformin received dapagliflozin 10 mg/d plus saxagliptin 5 mg/d. In sequential add-on trials, patients on metformin plus either saxagliptin 5 mg/d or dapagliflozin 10 mg/d received dapagliflozin 10 mg/d or saxagliptin 5 mg/d, respectively, as add-on therapy. After 24 weeks, incidences of adverse events and serious adverse events were similar between triple and dual therapy and between concomitant and sequential add-on regimens. Urinary tract infections were more common with sequential than with concomitant add-on therapy; genital infections were reported only with sequential add-on of dapagliflozin to saxagliptin plus metformin. Hypoglycaemia incidence was <2.0% across all analysis groups. In conclusion, the safety and tolerability of triple therapy with dapagliflozin, saxagliptin and metformin, as either concomitant or sequential add-on, were similar to dual therapy with either agent added to metformin.

Efficacy and safety of saxagliptin in patients with type 2 diabetes: A systematic review and meta-analysis

OBJECTIVE

To evaluate the comparative efficacy and safety of saxagliptin for type 2 diabetes (T2D).

METHODS

A systematic search of PubMed, Embase, the Cochrane Library, Web of Science, ClinicalTrials.gov and two Chinese databases for randomized controlled trials (RCTs) comparing saxagliptin with placebo or active comparators was performed up to July 2017. A complementary search was done to cover literature until March 2018. For continuous data, estimates were pooled using inverse variance methodology to calculate weighted mean differences (WMDs). Dichotomous data were presented as Mantel-Haenzel risk ratios (RRs).

RESULTS

Thirty-nine references of 30 RCTs involving 29,938 patients were analyzed. Compared with placebo, saxagliptin significantly reduced glycated hemoglobin (HbA1c, WMD -0.52%, 95% CI -0.60 to -0.44) and fasting plasma glucose (WMD -13.78 mg/dL, 95% CI -15.31 to -12.25), and increased the proportion of patients achieving HbA1c <7% (RR 1.64, 95% CI 1.53 to 1.75). When combined with submaximal-dose metformin, saxagliptin significantly increased the proportion of patients achieving HbA1c <7% compared with acarbose (RR 2.38, 95% CI 1.17 to 4.83) and uptitrated metformin (RR 1.30, 95% CI 1.04 to 1.63). Saxagliptin was similar to other DPP-4 inhibitors but inferior to liraglutide and dapagliflozin on glycemic control. Saxagliptin significantly decreased the incidences of overall adverse events compared with acarbose (RR 0.71, 95% CI 0.57 to 0.89) and liraglutide (RR 0.41, 95% CI 0.24 to 0.71) when added to metformin. Weight gain and hypoglycemia with saxagliptin was slightly but significantly higher than placebo and lower than sulfonylureas. Saxagliptin did not increase the risk of arthralgia, heart failure, pancreatitis and other adverse events.

CONCLUSIONS

Generally, saxagliptin has similar efficacy compared with most oral antidiabetic drugs and may be more effective than acarbose, while having a better safety profile than both acarbose and sulfonylureas.

The effects of dipeptidyl peptidase-4 inhibitors on bone fracture among patients with type 2 diabetes mellitus: A network meta-analysis of randomized controlled trials

Aim

The association between dipeptidyl peptidase-4 inhibitors (DPP-4is), a class of anti-diabetes, and bone fracture in patients with type 2 diabetes mellitus (T2DM) is unknown. This meta-analysis aimed to systematically evaluate the effects of DPP-4is on bone fracture in T2DM patients.

Methods

We searched the Cochrane Library, Embase, Medline and ClinicalTrials.gov from inception through April 28th, 2016 to identify randomized controlled trials (RCTs) that compared DPP-4is with placebo or other anti-diabetes in T2DM patients. RCTs lasting more than 12 weeks and having data on bone fracture were included. We conducted random-effects meta-analysis to estimate odds ratios (ORs) and their 95% confidence intervals (CIs), and network meta-analysis (NMA) to supplement direct comparisons. Predictive interval plot and node-splitting method were used to evaluate the heterogeneity and inconsistency for NMA, while the funnel plot was applied to explore publication bias. Besides, study quality was assessed according to Cochrane risk of bias tool.

Results

We identified 75 RCTs with a total of 70,207 patients and 11 treatments: interventions included 5 DPP-4is (alogliptin, linagliptin, saxagliptin, sitagliptin, vildagliptin), while controls included placebo and 5 other anti-diabetes (sulfonylureas, glucagon-like peptide-1 receptor agonists, metformin, thiazolidinediones, sodium-glucose co-transporter 2 inhibitors). In the NMA, the risk of fracture for alogliptin tended to decrease when versus placebo (OR, 0.51; 95% CI, 0.29 to 0.88). Besides, aloglitpin had a lower risk compared with linagliptin (OR, 0.45; 95% CI, 0.20 to 0.99) and saxagliption (OR, 0.46; 95%CI, 0.25 to 0.84); the risk was higher with saxagliptin when versus sitagliptin (OR, 1.90; 95% CI, 1.04 to 3.47) and sulfonylureas (OR, 1.98; 95% CI, 1.06 to 3.71). In the direct pairwise meta-analysis, alogliptin was associated with a non-significant tendency to reduction of bone fracture compared with placebo (OR, 0.54; 95% CI, 0.29 to 1.01). Ranking probability analysis indicated alogliptin decreased the risk of bone fracture most with a probability of 76.3%.

Conclusion

Alogliptin may be associated with a lower risk of bone fracture compared with placebo, linagliptin, or saxagliptin, while other anti-diabetes did not seem to have an association with the risk of bone fracture.

Renal outcomes with dipeptidyl peptidase-4 inhibitors

Dipeptidyl peptidase-4 inhibitors (DPP-4is) are increasingly being used in the management of type 2 diabetes (T2D). The present review summarizes the current knowledge of the effects of DPP-4is on renal outcomes by analyzing the experimental preclinical data, the effects of DPP-4is on urinary albumin-creatinine ratios (UACRs) and estimated glomerular filtration rates (eGFRs) from observational studies and clinical trials, and renal events (including kidney failure requiring renal replacement therapy) in recent large prospective cardiovascular outcome trials. Renal protection has been demonstrated in various animal models that have implicated different underlying mechanisms independent of glucose control, whereas prevention of new onset microalbuminuria and/or progression of albuminuria has been reported in some clinical studies, but with no significant effects on eGFR in most of them. The long-term clinical effects of DPP-4is on renal outcomes and the development of end-stage renal disease remain largely unknown and, thus, demand further investigations in prospective trials and long-term observational studies. In conclusion, despite promising results in animal models, data on surrogate biological markers of renal function and clinical renal outcomes remain rather scanty in patients with T2D, and mostly demonstrate the safety rather than true efficacy of DPP-4is.

Type 2 Diabetes and Osteoporosis: A Guide to Optimal Management

CONTEXT

Both type 2 diabetes (T2D) and osteoporosis are affected by aging and quite often coexist. Furthermore, the fracture risk in patients with T2D is increased. The aim of this article is to review updated information on osteoporosis and fracture risk in patients with T2D, to discuss the effects of diabetes treatment on bone metabolism, as well as the effect of antiosteoporotic medications on the incidence and control of T2D, and to provide a personalized guide to the optimal management.

EVIDENCE ACQUISITION

A systematic literature search for human studies was conducted in three electronic databases (PubMed, Cochrane, and EMBASE) until March 2017. Regarding recommendations, we adopted the grading system introduced by the American College of Physicians.

EVIDENCE SYNTHESIS

The results are presented in systematic tables. Healthy diet and physical exercise are very important for the prevention and treatment of both entities. Metformin, sulfonylureas, dipeptidyl peptidase-4 inhibitors, and glucagon-like peptide-1 receptor agonists should be preferred for the treatment of T2D in these patients, whereas strict targets should be avoided for the fear of hypoglycemia, falls, and fractures. Insulin should be used with caution and with careful measures to avoid hypoglycemia. Thiazolidinediones and canagliflozin should be avoided, whereas other sodium-dependent glucose transporter 2 inhibitors are less well-validated options. Insulin therapy is the preferred method for achieving glycemic control in hospitalized patients with T2D and fractures. The treatment and monitoring of osteoporosis should be continued without important amendments because of the presence of T2D.

CONCLUSIONS

Patients with coexisting T2D and osteoporosis should be managed in an optimal way according to scientific evidence.

Nonclinical and clinical pharmacology evidence for cardiovascular safety of saxagliptin

BACKGROUND

In the Saxagliptin Assessment of Vascular Outcomes Recorded in Patients with Diabetes Mellitus (SAVOR) trial in patients with type 2 diabetes mellitus (T2D) at high risk of cardiovascular (CV) disease, saxagliptin did not increase the risk for major CV adverse events. However, there was an unexpected imbalance in events of hospitalization for heart failure (hHF), one of six components of the secondary CV composite endpoint, with a greater number of events observed with saxagliptin. Here, we examined findings from nonclinical safety and clinical pharmacology studies of saxagliptin with the aim of identifying any potential signals of myocardial injury.

METHODS

In vitro and in vivo (rat, dog, monkey) safety pharmacology and toxicology studies evaluating the potential effects of saxagliptin and its major active metabolite, 5-hydroxy saxagliptin, on the CV system are reviewed. In addition, results from saxagliptin clinical studies are discussed: one randomized, 2-period, double-blind, placebo-controlled single-ascending-dose study (up to 100 mg); one randomized, double-blind, placebo-controlled, sequential, multiple-ascending-high-dose study (up to 400 mg/day for 14 days); and one randomized, double-blind, 4-period, 4-treatment, cross-over thorough QTc study (up to 40 mg/day for 4 days) in healthy volunteers; as well as one randomized, placebo-controlled, sequential multiple-ascending-dose study in patients with T2D (up to 50 mg/day for 14 days).

RESULTS

Neither saxagliptin nor 5-hydroxy saxagliptin affected ligand binding to receptors and ion channels (e.g. potassium channels) or action potential duration in in vitro studies. In animal toxicology studies, no changes in the cardiac conduction system, blood pressure, heart rate, contractility, heart weight, or heart histopathology were observed. In healthy participants and patients with T2D, there were no findings suggestive of myocyte injury or fluid overload. Serum chemistry abnormalities indicative of cardiac injury, nonspecific muscle damage, or fluid homeostasis changes were infrequent and balanced across treatment groups. There were no QTc changes associated with saxagliptin. No treatment-emergent adverse events suggestive of heart failure or myocardial damage were reported.

CONCLUSIONS

The saxagliptin nonclinical and clinical pharmacology programs did not identify evidence of myocardial injury and/or CV harm that may have predicted or may explain the unexpected imbalance in the rate of hHF observed in SAVOR.

Assessment of Saxagliptin Efficacy: Meta-Analysis of 14 Phase 2 and 3 Clinical Trials

INTRODUCTION

This meta-analysis of data from 14 phase 2 and 3, double-blind, randomized, controlled 12- and 24-week studies (N = 4632) summarizes saxagliptin efficacy in patients with type 2 diabetes (T2D) across treatment regimens.

METHODS

Patients received saxagliptin 5 mg/d or control as either monotherapy (n = 1196 vs placebo), add-on therapy (n = 2139 vs placebo and n = 514 vs uptitrated sulfonylurea), or initial combination therapy (n = 619 vs control monotherapy). Patients with renal impairment received saxagliptin 2.5 mg/d or placebo (n = 164).

RESULTS

Mean baseline glycated hemoglobin (A1C) ranged from 8.07% to 9.43% for the saxagliptin and control groups across treatment regimens. A1C reduction from baseline was greater with saxagliptin versus control for all studies combined (mean treatment difference [95% CI]: -0.55% [-0.63%, -0.47%]) and when used as monotherapy (-0.52% [-0.63, -0.40%]), add-on (-0.55% [-0.69%, -0.40%] vs placebo; -0.72% [-0.88%, -0.56%] vs uptitrated sulfonylurea), initial combination therapy (-0.54% [-0.73%, -0.35%] vs control monotherapy), and in patients with renal impairment (-0.42% [-0.75%, -0.09%]). Similar reductions in A1C versus control were noted for patients <65 years (-0.55% [-0.67%, -0.43%]) and ≥65 years (-0.54% [-0.69%, -0.38%]) and for men (-0.54% [-0.69%, -0.40%]) and women (-0.55% [-0.64%, -0.47%]) across treatment regimens. More patients achieved A1C <7% (39% vs 23%) and A1C ≤6.5% (24% vs 14%) with saxagliptin than with placebo or active-control treatment. Saxagliptin versus control was associated with a reduction in glucagon area under the curve (AUC) from baseline and increases in insulin AUC, C-peptide AUC, and the homeostasis model assessment of β-cell function.

CONCLUSION

Results of this meta-analysis demonstrate the consistency of saxagliptin efficacy in different subgroups of patients with T2D across treatment regimens.

FUNDING

AstraZeneca.

Diabetes Drug Effects on the Skeleton

Diabetes be it type 1 or type 2 is associated with an increased risk of fragility fractures. The mechanisms underlying this increased risk are just being elucidated. Anti-diabetes medications are crucial for maintaining glucose control and for preventing micro- and macrovascular complications in diabetes. However, they may modulate fracture risk in diabetes in different ways. Thiazolidinediones have demonstrated an unfavorable effect on the skeleton, while metformin and sulfonylureas may have a neutral if not beneficial effect on bone. The use of insulin has been associated with an increased risk of fragility fractures though it is not clear whether it is due to direct influence of insulin or whether it is mediated through hypoglycemia and increased falls risk. The overall effect of incretin mimetics appears to be beneficial; however, this has to be elucidated further. The bone effects of pramlintide, a synthetic analog of amylin, have not been explored fully. Finally, issues regarding bone safety of SGLT2 (sodium-dependent glucose transporter 2) inhibitors, the newest anti-diabetic medications on the market are of concern. The purpose of this review is to provide a comprehensive overview of the effect of these medications on bone metabolism and the studies exploring the risk or lack thereof of these medications on bone loss and fragility fractures.

Postauthorization safety study of the DPP-4 inhibitor saxagliptin: a large-scale multinational family of cohort studies of five outcomes

OBJECTIVE

To evaluate the risk of serious adverse events among patients with type 2 diabetes mellitus initiating saxagliptin compared with oral antidiabetic drugs (OADs) in classes other than dipeptidyl peptidase-4 (DPP-4) inhibitors.

RESEARCH DESIGN AND METHODS

Cohort studies using 2009-2014 data from two UK medical record data sources (Clinical Practice Research Datalink, The Health Improvement Network) and two USA claims-based data sources (HealthCore Integrated Research Database, Medicare). All eligible adult patients newly prescribed saxagliptin (n=110 740) and random samples of up to 10 matched initiators of non-DPP-4 inhibitor OADs within each data source were selected (n=913 384). Outcomes were hospitalized major adverse cardiovascular events (MACE), acute kidney injury (AKI), acute liver failure (ALF), infections, and severe hypersensitivity events, evaluated using diagnostic coding algorithms and medical records. Cox regression was used to determine HRs with 95% CIs for each outcome. Meta-analyses across data sources were performed for each outcome as feasible.

RESULTS

There were no increased incidence rates or risk of MACE, AKI, ALF, infection, or severe hypersensitivity reactions among saxagliptin initiators compared with other OAD initiators within any data source. Meta-analyses demonstrated a reduced risk of hospitalization/death from MACE (HR 0.91, 95% CI 0.85 to 0.97) and no increased risk of hospitalization for infection (HR 0.97, 95% CI 0.93 to 1.02) or AKI (HR 0.99, 95% CI 0.88 to 1.11) associated with saxagliptin initiation. ALF and hypersensitivity events were too rare to permit meta-analysis.

CONCLUSIONS

Saxagliptin initiation was not associated with increased risk of MACE, infection, AKI, ALF, or severe hypersensitivity reactions in clinical practice settings.

TRIAL REGISTRATION NUMBER

NCT01086280, NCT01086293, NCT01086319, NCT01086306, and NCT01377935; Results.

Emerging use of combination therapies for the management of type 2 diabetes - focus on saxagliptin and dapagliflozin

AIMS

The aim of this article is to review the safety and efficacy data of dapagliflozin, saxagliptin, and their combination in the management of patients with type 2 diabetes. Evidence for the use of the single-tablet combination formulation is also presented.

METHODS

A nonsystematic literature review was performed using the Ovid, PubMed, and Google Scholar databases.

RESULTS

The addition of dapagliflozin/saxagliptin to metformin can lower mean hemoglobin A1c by as much as 1.47% and lead to weight loss of 0.5-2.0 kg. The risk of genital infections with combination therapy is lower than observed with dapagliflozin alone, suggestive of a protective effect. Adverse event risk at 52-week follow-up was not increased beyond that seen with either monotherapy.

CONCLUSION

Dapagliflozin/saxagliptin combination is generally well tolerated and is an effective tool in helping patients with diabetes improve glycemic control.

Boning up on DPP4, DPP4 substrates, and DPP4-adipokine interactions: Logical reasoning and known facts about bone related effects of DPP4 inhibitors

Dipeptidyl peptidase 4 (DPP4) is a conserved exopeptidase with an important function in protein regulation. The activity of DPP4, an enzyme which can either be anchored to the plasma membrane or circulate free in the extracellular compartment, affects the glucose metabolism, cellular signaling, migration and differentiation, oxidative stress and the immune system. DPP4 is also expressed on the surface of osteoblasts, osteoclasts and osteocytes, and was found to play a role in collagen metabolism. Many substrates of DPP4 have an established role in bone metabolism, among which are incretins, gastrointestinal peptides and neuropeptides. In general, their effects favor bone formation, but some effects are complex and have not been completely elucidated. DPP4 and some of its substrates are known to interact with adipokines, playing an essential role in the energy metabolism. The prolongation of the half-life of incretins through DPP4 inhibition led to the development of these inhibitors to improve glucose tolerance in diabetes. Current literature indicates that the inhibition of DPP4 activity might also result in a beneficial effect on the bone metabolism, but the long-term effect of DPP4 inhibition on fracture outcome has not been entirely established. Diabetic as well as postmenopausal osteoporosis is associated with an increased activity of DPP4, as well as a shift in the expression levels of DPP4 substrates, their receptors, and adipokines. The interactions between these factors and their relationship in bone metabolism are therefore an interesting field of study.

Dipeptidyl peptidase-4 inhibitors and bone metabolism: is vitamin D the link?

AIMS

Dipeptidyl peptidase-4 inhibitors (DPP4-Is) represent a promising class of agents for type 2 diabetes treatment. Experimental models and clinical studies have reported positive effects of DPP4-Is on bone; however, how DPP4-Is positively impact bone homeostasis in humans remains an unanswered question. Aim of this study investigated the relationship between treatment with DPP4-Is and vitamin D balance in patients with type 2 diabetes.

METHODS

This is a cross-sectional study. A total of 295 consecutive individuals with type 2 diabetes referring to our diabetes outpatient clinics were enrolled; among them, 53 % were in treatment with DPP4-Is. Metabolic profile and routine biochemistry were assessed by standard methods; serum 25(OH) vitamin D levels [25(OH)D] were measured by colorimetric method (LAISON, DiaSorin).

RESULTS

DPP4-Is-treated participants had significantly higher serum 25(OH)D levels then those undertaking other antidiabetic therapies (18.4 ± 10.7 vs. 14.9 ± 8.6 ng/ml, p = 0.004); this association persisted after adjusting for all major confounders. Increased 25(OH)D concentrations also correlated with the duration of DPP4-Is treatment and with a stronger DPP4 inhibitory activity.

CONCLUSIONS

DPP4-Is treatment is associated with improved vitamin D balance in people with type 2 diabetes; our findings suggest that vitamin D may underlie the link between DPP4-Is and bone metabolism.

Clinical pharmacology of dipeptidyl peptidase 4 inhibitors indicated for the treatment of type 2 diabetes mellitus

Dipeptidyl peptidase-4 (DPP-4) inhibitors are a class of oral antidiabetic drugs that improve glycaemic control without causing weight gain or increasing hypoglycaemic risk in patients with type 2 diabetes mellitus (T2DM). The eight available DPP-4 inhibitors, including alogliptin, anagliptin, gemigliptin, linagliptin, saxagliptin, sitagliptin, teneligliptin, and vildagliptin, are small molecules used orally with identical mechanism of action and similar safety profiles in patients with T2DM. DPP-4 inhibitors may be used as monotherapy or in double or triple combination with other oral glucose-lowering agents such as metformin, thiazolidinediones, or sulfonylureas. Although DPP-4 inhibitors have the same mode of action, they differ by some important pharmacokinetic and pharmacodynamic properties that may be clinically relevant in some patients. The main differences between the eight gliptins include: potency, target selectivity, oral bioavailability, elimination half-life, binding to plasma proteins, metabolic pathways, formation of active metabolite(s), main excretion routes, dosage adjustment for renal and liver insufficiency, and potential drug-drug interactions. The off-target inhibition of selective DPP-4 inhibitors is responsible for multiorgan toxicities such as immune dysfunction, impaired healing, and skin reactions. As a drug class, the DPP-4 inhibitors have become accepted in clinical practice due to their excellent tolerability profile, with a low risk of hypoglycaemia, a neutral effect on body weight, and once-daily dosing. It is unknown if DPP-4 inhibitors can prevent disease progression. More clinical studies are needed to validate the optimal regimens of DPP-4 inhibitors for the management of T2DM when their potential toxicities are closely monitored.

Dipeptidyl peptidase-4 inhibition in chronic kidney disease and potential for protection against diabetes-related renal injury

AIMS

Type 2 diabetes mellitus (T2DM) is associated with a high risk of chronic kidney disease (CKD). About 20% of patients with T2DM have CKD of stage ≥ 3; up to 40% have some degree of CKD. Beyond targeting all renal risk factors together, renin-angiotensin-aldosterone system blockers are to date the only effective mainstay for the treatment of diabetic kidney disease (DKD). Indeed, several potentially nephroprotective agents have been in use, which have been unsuccessful. Some glucose-lowering agents, including dipeptidyl peptidase-4 inhibitors (DPP-4i), have shown promising results. Here, we discuss the evidence that glucose lowering with DPP-4i may be an option for protecting against diabetes-related renal injury.

DATA SYNTHESIS

A comprehensive search was performed of the literature using the terms "alogliptin," "linagliptin," "saxagliptin," "sitagliptin," and "vildagliptin" for original articles and reviews addressing this topic. DPP-4i are an effective, well-tolerated treatment option for T2DM with any degree of renal impairment. Preclinical observations and clinical studies suggest that DPP-4i might also be a promising strategy for the treatment of DKD. The available data are in favor of saxagliptin and linagliptin, but the consistency of results points to the possible nephroprotective effect of DPP-4i. This property appears to be independent of glucose lowering and can potentially complement other therapies that preserve renal function. Larger prospective clinical trials are ongoing, which might strengthen these hypothesis-generating findings.

CONCLUSIONS

The improvement in albuminuria associated with DPP-4i suggests that these agents may provide renal benefits beyond their glucose-lowering effects, thus offering direct protection from DKD. These promising results must be interpreted with caution and need to be confirmed in forthcoming studies.

Comparative review of dipeptidyl peptidase-4 inhibitors and sulphonylureas

Type 2 diabetes (T2DM) is a progressive disease, and pharmacotherapy with a single agent does not generally provide durable glycaemic control over the long term. Sulphonylurea (SU) drugs have a history stretching back over 60 years, and have traditionally been the mainstay choice as second-line agents to be added to metformin once glycaemic control with metformin monotherapy deteriorates; however, they are associated with undesirable side effects, including increased hypoglycaemia risk and weight gain. Dipeptidyl peptidase (DPP)-4 inhibitors are, by comparison, more recent, with the first compound being launched in 2006, but the class now globally encompasses at least 11 different compounds. DPP-4 inhibitors improve glycaemic control with similar efficacy to SUs, but do not usually provoke hypoglycaemia or weight gain, are relatively free from adverse side effects, and have recently been shown not to increase cardiovascular risk in large prospective safety trials. Because of these factors, DPP-4 inhibitors have become an established therapy for T2DM and are increasingly being positioned earlier in treatment algorithms. The present article reviews these two classes of oral antidiabetic drugs (DPP-4 inhibitors and SUs), highlighting differences and similarities between members of the same class, as well as discussing the potential advantages and disadvantages of the two drug classes. While both classes have their merits, the choice of which to use depends on the characteristics of each individual patient; however, for the majority of patients, DPP-4 inhibitors are now the preferred choice.

Saxagliptin for the treatment of diabetes - a focus on safety

INTRODUCTION

The safety of agents used to treat type 2 diabetes (T2D), a chronic disease requiring life-long intervention, is of particular interest. Saxagliptin is a potent and selective DPP-4 inhibitor that has emerged as a therapeutic option for T2D.

AREAS COVERED

Its safety was assessed in a development program of 20 phase 2/3 randomized clinical trials and in SAVOR-TIMI 53 trial that evaluated the cardiovascular outcomes. In order to capture any further safety signals, mainly in the long-term, a post-marketing safety surveillance is ongoing. This paper discusses the tolerability and safety profile of the agent, including cardiovascular, renal, pancreatic, hepatic and bone adverse events.

EXPERT OPINION

Saxagliptin is a safe therapeutic option for patients with T2D, with low risk of hypoglycemia and good tolerability. It demonstrated cardiovascular safety (including in patients with pre-existing cardiovascular disease and/or HF) and safety with respect to all-cause mortality and adverse events of special interest. In SAVOR-TIMI53, saxagliptin was associated with an unexpected increased risk of HF hospitalization, mainly in the first 12 months; a mechanistic explanation for this has not been found. Further research needs to elucidate the effect of antidiabetic drugs on the heart, by including biomarkers and echocardiographic sub-studies within large outcome trials.

Incidence of Fractures in Patients With Type 2 Diabetes in the SAVOR-TIMI 53 Trial

OBJECTIVE

Patients with type 2 diabetes have an increased risk of bone fractures, the predisposing factors for which are unknown. Treatment with thiazolidinediones (TZDs) further increases the incidence of osteoporotic fractures. In the Saxagliptin Assessment of Vascular Outcomes Recorded in Patients with Diabetes Mellitus-Thrombolysis in Myocardial Infarction 53 (SAVOR-TIMI 53) trial, fractures were considered an adverse event of special interest, and information regarding fractures was collected.

RESEARCH DESIGN AND METHODS

We compared the incidence of fractures among the 8,280 patients who were assigned to treatment with saxagliptin with that in the 8,212 patients who were assigned to placebo. We further analyzed the participants' baseline characteristics and fracture risk.

RESULTS

During a median follow-up of 2.1 years, 241 patients (2.9%) in the saxagliptin group and 240 (2.9%) in the placebo group experienced a fracture (hazard ratio [HR] 1.00 [95% CI 0.83-1.19]). Event rates for fractures were the same in both treatment arms: 14.7 per 1,000 patient-years in the entire population and 14.0 in the on-treatment population (first event only). Fracture risk was similar in patients treated with saxagliptin or placebo across different subgroups defined by race, cardiovascular risk, and renal function. A multivariable Cox regression analysis showed that risk of fracture was associated with female sex (P < 0.0001), longer diabetes duration (P < 0.0001), older age (P = 0.002), major hypoglycemic events (P = 0.01), noncompliance with study drug (P = 0.01), and treatment with TZDs (P = 0.03).

CONCLUSIONS

In a large population of older patients with type 2 diabetes, treatment with saxagliptin was not associated with an increased risk of fractures. The association between longer diabetes duration and increased risk of bone fracture is an intriguing finding.

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.

Efficacy and safety of saxagliptin in older participants in the SAVOR-TIMI 53 trial

OBJECTIVE

To examine the safety and cardiovascular (CV) effects of saxagliptin in the predefined elderly (≥65 years) and very elderly (≥75 years) subpopulations of the Saxagliptin Assessment of Vascular Outcomes Recorded in Patients with Diabetes Mellitus-Thrombolysis in Myocardial Infarction 53 (SAVOR-TIMI 53) trial.

RESEARCH DESIGN AND METHODS

Individuals ≥40 years (n = 16,492; elderly, n = 8,561; very elderly, n = 2,330) with HbA1c ≥6.5% (47.5 mmol/mol) and ≤12.0% (107.7 mmol/mol) were randomized (1:1) to saxagliptin (5 or 2.5 mg daily) or placebo in a double-blind trial for a median follow-up of 2.1 years.

RESULTS

The hazard ratio (HR) for the comparison of saxagliptin versus placebo for the primary end point (composite of CV mortality, myocardial infarction, or ischemic stroke) was 0.92 for elderly patients vs. 1.15 for patients <65 years (P = 0.06) and 0.95 for very elderly patients. The HRs for the secondary composite end points in the entire cohort, elderly cohort, and very elderly cohort were similar. Although saxagliptin increased the risk of hospitalization for heart failure in the overall saxagliptin population, there was no age-based treatment interaction (P = 0.76 for elderly patients vs. those <65 years; P = 0.34 for very elderly patients vs. those <75 years). Among saxagliptin-treated individuals with baseline HbA1c ≥7.6% (59.6 mmol/mol), the mean change from baseline HbA1c at 2 years was -0.69%, -0.64%, -0.66%, and -0.66% for those ≥65, <65, ≥75, and <75 years old, respectively. The incidence of overall adverse events (AEs) and serious AEs was similar between saxagliptin and placebo in all cohorts; however, hypoglycemic events were higher for saxagliptin versus placebo regardless of age.

CONCLUSIONS

The SAVOR-TIMI 53 trial supports the overall CV safety of saxagliptin in a robust number of elderly and very elderly participants, although the risk of heart failure hospitalization was increased irrespective of age category. AEs and serious AEs as well as glycemic efficacy of saxagliptin in elderly patients are similar to those found in younger patients.

Dipeptidyl peptidase-4 inhibitors and the risk of community-acquired pneumonia in patients with type 2 diabetes

AIMS

To determine whether the use of dipeptidyl peptidase-4 (DPP-4) inhibitors is associated with an increased risk of community-acquired pneumonia.

METHODS

The UK Clinical Practice Research Datalink and the Hospital Episodes Statistics database were used to conduct a nested case-control analysis within a cohort of new users of antidiabetic drugs between 2007 and 2012. Incident cases of hospitalization for community-acquired pneumonia were matched with up to 20 controls on age, duration of treated diabetes, calendar year and duration of follow-up. Conditional logistic regression models were used to estimate the odds ratios (ORs) and 95% confidence intervals (CIs) for hospitalization for community-acquired pneumonia associated with current use of DPP-4 inhibitors compared with current use of two or more oral antidiabetic drugs.

RESULTS

The cohort included 49,653 patients, of whom 562 were hospitalized for community-acquired pneumonia during follow-up (incidence rate 5.2/1000 person-years). Compared with current use of two or more oral antidiabetic drugs, current use of DPP-4 inhibitors was not associated with an increased risk of hospitalized community-acquired pneumonia overall (adjusted OR 0.80, 95% CI 0.50-1.29) or according to duration of use (p for trend = 0.57).

CONCLUSIONS

The use of DPP-4 inhibitors was not associated with an increased risk of hospitalization for community-acquired pneumonia. Additional research is needed to assess the association between these drugs and other serious infections.

Safety of dipeptidyl peptidase-4 inhibitors for treating type 2 diabetes

INTRODUCTION

Dipeptidyl peptidase-4 (DPP-4) inhibitors (gliptins) occupy a growing place in the armamentarium of drugs used for the management of hyperglycemia in type 2 diabetes, although some safety concerns have been raised in recent years.

AREAS COVERED

An updated review providing an analysis of available safety data (meta-analyses, randomized controlled trials, observational cohort and case-control studies and pharmacovigilance reports) with five commercialized DPP-4 inhibitors (sitagliptin, vildagliptin, saxagliptin, alogliptin, linagliptin). A special focus is given to overall safety profile; pancreatic adverse events (AEs) (acute pancreatitis, pancreatic cancer); overall cardiovascular safety (myocardial infarction and stroke); congestive heart failure concern and finally, safety in special populations (elderly, renal impairment).

EXPERT OPINION

The good tolerance/safety profile of DPP-4 inhibitors has been largely confirmed, including in more fragile populations (elderly, renal impairment) with almost no increased risk of infection or gastrointestinal AEs, no weight gain and a minimal risk of hypoglycemia. Although an increased risk of acute pancreatitis and pancreatic cancer was suspected, the complete set of available data appears reassuring so far. Cardiovascular safety of DPP-4 inhibitors has been proven but an unexpected increased risk of heart failure has been reported which should be confirmed in ongoing trials and better understood. Further postmarketing surveillance is recommended.

Insights into bone fragility in diabetes: the crucial role of bone quality on skeletal strength

Meta-analyses have revealed that the relative risk of hip fractures in patients with type 1 and type 2 diabetes mellitus is higher than that in non-diabetic subjects. The risk of fracture in patients with diabetes mellitus increases along with a decrease in bone mineral density (BMD) similarly to those in non-diabetic patients. However, the observed risk of fracture is higher than expected one by BMD in both type 1 and type 2 diabetic patients, indicating that precise estimation of bone fragility by BMD values in patients with diabetes is difficult. Bone strength consists of BMD and bone quality, for this reason, poor bone quality is a most suitable and explicable cause for elevated fracture risk in this population. This bone fragility observed in patients with diabetes mellitus is caused by unique pathogenesis in diabetes, suggesting that osteoporosis in diabetic patients may be one of the diabetic complications and that specific diagnostic criteria for this osteoporosis is required. Bone quality indicators closely related to bone fragility are required to be identified to establish a diagnostic method for osteoporosis in patients with diabetes mellitus.

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.

Antihyperglycaemic therapies and cancer risk

AIMS

This review is aimed at highlighting the potential mitogenic/tumour growth-promoting or antimitogenic/tumour growth-inhibiting effects of the main antihyperglycaemic drug classes.

METHODS

We review and discuss the most current studies evaluating the association between antidiabetic medications used in clinical practice and malignancies as described so far.

RESULTS

Metformin seems to be the only antidiabetic drug to exert protective effects both on monotherapy and also when combined with other oral antidiabetic drugs or insulins in several site-specific cancers. In contrast, several other drug classes may increase cancer risk. Some reason for concern remains regarding sulphonylureas and also the incretin-based therapies regarding pancreas and thyroid cancers and the sodium glucose cotransporter-2 inhibitors as well as pioglitazone regarding bladder cancer. The majority of meta-analyses suggest that there is no evidence for a causal relationship between insulin glargine and elevated cancer risk, although the studies have been controversially discussed. For α-glucosidase inhibitors and glinides, neutral or only few data upon cancer risk exist.

CONCLUSION

Although the molecular mechanisms are not fully understood, a potential risk of mitogenicity and tumour growth promotion cannot be excluded in case of several antidiabetic drug classes. However, more large-scale, randomized, well-designed clinical studies with especially long follow-up time periods are needed to get reliable answers to these safety issues.