Sitagliptin and other ‘gliptins’ - why prescribe them?

Introduction In 2008, the Federal Drug Administration (FDA) required all new glucose-lowering therapies to show cardiovascular safety, and this applies to the dipeptidyl peptidase (DPP)-4 inhibitors (‘gliptins’). At present, there is contradictory evidence on whether the gliptins increase hospitalizations for heart failure. Areas covered This is an evaluation of the Trial Evaluating Cardiovascular Outcomes with Sitagliptin (TECOS) in high risk cardiovascular subjects with type 2 diabetes [1]. TECOS demonstrated non-inferiority for sitagliptin over placebo for the primary outcome, which was cardiovascular death, nonfatal myocardial infarction, nonfatal stroke, or hospitalization for unstable angina. There was no difference in the rate of hospitalization for heart failure between sitagliptin and placebo. Expert Opinion Despite the results of TECOS, debate over the effects of sitagliptin on the rates of hospitalizations for heart failure continues with some recent studies suggesting increased rates. Recently, empagliflozin (an inhibitor of sodium-glucose cotransporter 2) has been shown to reduce cardiovascular outcomes in subjects with type 2 diabetes, including the rates of hospitalization for heart failure. In our opinion, these positive findings with empagliflozin suggest that it should be prescribed in preference to the gliptins, including sitagliptin, unless any positive cardiovascular outcomes are reported for the gliptins.

Fixed-dose combination therapy for type 2 diabetes: sitagliptin plus pioglitazone

Importance of the field: Type 2 diabetes is typically associated with insulin resistance and dysfunction of insulin-secreting pancreatic beta-cells. Addressing these defects often requires therapy with a combination of differently acting antidiabetic agents. A potential novel combination in development brings together the dipeptidyl peptidase-4 (DPP-4) inhibitor sitagliptin with the thiazolidinedione pioglitazone into a fixed-dose single-tablet combination. The former component acts mainly to increase prandial insulin secretion; the latter improves insulin sensitivity.

One year of sitagliptin treatment protects against islet amyloid-associated β-cell loss and does not induce pancreatitis or pancreatic neoplasia in mice

The dipeptidyl peptidase-4 (DPP-4) inhibitor sitagliptin is an attractive therapy for diabetes, as it increases insulin release and may preserve β-cell mass. However, sitagliptin also increases β-cell release of human islet amyloid polypeptide (hIAPP), the peptide component of islet amyloid, which is cosecreted with insulin. Thus, sitagliptin treatment may promote islet amyloid formation and its associated β-cell toxicity. Conversely, metformin treatment decreases islet amyloid formation by decreasing β-cell secretory demand and could therefore offset sitagliptin's potential proamyloidogenic effects. Sitagliptin treatment has also been reported to be detrimental to the exocrine pancreas. We investigated whether long-term sitagliptin treatment, alone or with metformin, increased islet amyloid deposition and β-cell toxicity and induced pancreatic ductal proliferation, pancreatitis, and/or pancreatic metaplasia/neoplasia. hIAPP transgenic and nontransgenic littermates were followed for 1 yr on no treatment, sitagliptin, metformin, or the combination. Islet amyloid deposition, β-cell mass, insulin release, and measures of exocrine pancreas pathology were determined. Relative to untreated mice, sitagliptin treatment did not increase amyloid deposition, despite increasing hIAPP release, and prevented amyloid-induced β-cell loss. Metformin treatment alone or with sitagliptin decreased islet amyloid deposition to a similar extent vs untreated mice. Ductal proliferation was not altered among treatment groups, and no evidence of pancreatitis, ductal metaplasia, or neoplasia were observed. Therefore, long-term sitagliptin treatment stimulates β-cell secretion without increasing amyloid formation and protects against amyloid-induced β-cell loss. This suggests a novel effect of sitagliptin to protect the β-cell in type 2 diabetes that appears to occur without adverse effects on the exocrine pancreas.

Exenatide and sitagliptin decrease interleukin 1β, matrix metalloproteinase 9, and nitric oxide synthase 2 gene expression but does not reduce alveolar bone loss in rats with periodontitis

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Fixed-dose combination therapy for type 2 diabetes:sitagliptin plus pioglitazone

Type 2 diabetes is typically associated with insulin resistance and dysfunction of insulin-secreting pancreatic beta-cells. Addressing these defects often requires therapy with a combination of differently acting antidiabetic agents. A potential novel combination in development brings together the dipeptidyl peptidase-4 (DPP-4) inhibitor sitagliptin with the thiazolidinedione pioglitazone into a fixed-dose single-tablet combination. The former component acts mainly to increase prandial insulin secretion; the latter improves insulin sensitivity.

The efficacy and safety of imeglimin as add-on therapy in patients with type 2 diabetes inadequately controlled with sitagliptin monotherapy

OBJECTIVE: This 12-week study assessed the efficacy and tolerability of imeglimin as add-on therapy to the dipeptidyl peptidase-4 inhibitor sitagliptin in patients with type 2 diabetes inadequately controlled with sitagliptin monotherapy. RESEARCH DESIGN AND METHODS: In a multicenter, randomized, double-blind, placebo-controlled, parallel-group study, imeglimin (1,500 mg b.i.d.) or placebo was added to sitagliptin (100 mg q.d.) over 12weeks in 170 patientswith type 2 diabetes (mean age 56.8 years; BMI 32.2 kg/m2) that was inadequately controlled with sitagliptin alone (A1C ≥7.5%) during a 12-week run-in period. The primary ef ficacy end point was the change in A1C from baseline versus placebo; secondary end points included corresponding changes in fasting plasma glucose (FPG) levels, strati fication by baseline A1C, and percentage of A1C responders. RESULTS: Imeglimin reduced A1C levels (least-squares mean difference) from baseline (8.5%) by 0.60% compared with an increase of 0.12% with placebo (between-group difference 0.72%, P < 0.001). The corresponding changes in FPG were -0.93 mmol/L with imeglimin vs. -0.11 mmol/L with placebo (P = 0.014). With imeglimin, the A1C level decreased by ≥0.5% in 54.3% of subjects vs. 21.6% with placebo (P < 0.001), and 19.8%of subjects receiving imeglimin achieved a decrease in A1C level of ≤7% compared with subjects receiving placebo (1.1%) (P = 0.004). Imeglimin was generally well tolerated, with a safety pro file comparable to placebo and no related treatment-emergent adverse events. CONCLUSIONS: Imeglimin demonstrated incremental efficacy benefits as add-on therapy to sitagliptin, with comparable tolerability to placebo, highlighting the potential for imeglimin to complement other oral antihyperglycemic therapies. © 2014 by the American Diabetes Association.

Drugs for diabetes and obesity

14.1 Drugs for diabetes 14.1.1 Diabetes mellitus 14.1.2 Physiology of the pancreas 14.1.3 Insulin replacement therapy 14.1.4 Metformin 14.1.5 Acarbose 14.1.6 Sulfonylureas 14.1.7 Glitazones 14.1.8 Glucagon-like peptide-1, exenatide and sitagliptin 14.2 Drugs for obesity 14.2.1 Introduction 14.2.2 Amphetamine 14.2.3 Phentermine 14.2.5 Orlistat

Exenatide extended-release; clinical trials, patient preference, and economic considerations

Type 2 diabetes remains an escalating world-wide problem, despite a range of treatments. The revelation that insulin secretion is under the control of a gut hormone, glucagon-like peptide 1 (GLP-1) led to a new paradigm in the management of type 2 diabetes, medicines that directly stimulate, or that prolong the actions of the endogenous GLP-1, at its receptors. Exenatide is an agonist at the GLP-1 receptors, and was initially developed as a subcutaneous twice daily medication, ExBID. The clinical trials with ExBID established a role for exenatide in the treatment of type 2 diabetes. Subsequently, once weekly exenatide (ExQW) was shown to have advantages over ExBID, and there is now more emphasis on the development of ExQW. ExQW alone reduces glycosylated haemoglobin (HbA1c) and body weight, and is well tolerated. ExQW has been compared to sitagliptin, pioglitazone and metformin, and shown to have a greater ability to reduce HbA1c than these other medicines. The only preparation of insulin, which ExQW has been compared to, is insulin glargine, and the ExQW has some favourable properties in this comparison, notably causing weight loss, compared to the gain with insulin glargine. ExQW has been compared to another GLP-1 receptor agonist, liraglutide, and ExQW is non-inferior to liraglutide in reducing HbA1c. The small amount of evidence available, shows that subjects with type 2 diabetes, prefer ExQW to ExBID, and that adherence was high to these in the clinical trial setting. Healthcare and economic modelling suggests that ExQW will reduce diabetic complications and be cost-effective, compared to other medications, with long term use. Little is known about whether subjects with type 2 diabetes prefer ExQW to other medicines, and whether adherence is good to ExQW in practice, and these important topics require further study.

Dapagliflozin – do we need it registered for type 2 diabetes?

INTRODUCTION: Inhibitors of the sodium-glucose co-transporter 2 (SGLT2) promote the excretion of glucose to reduce glycated hemoglobin (HbA1c) levels. Canagliflozin was the first SGLT2 inhibitor to be approved by the US FDA for use in the treatment of type 2 diabetes, and recently dapagliflozin has also been approved. AREAS COVERED: We evaluated a recent Phase III clinical trial with dapagliflozin. EXPERT OPINION: Dapagliflozin was studied as add-on therapy to sitagliptin with or without metformin, and was shown to lower HbA1c levels and body weight. The incidence of hypoglycaemia was low with dapagliflozin, but it did increase the incidence of urogenital infections. As no clear benefits have been identified for dapagliflozin over canagliflozin, which was the first gliflozin registered by the FDA, we do not fully understand why it was necessary to register dapagliflozin. Given that there are no completed cardiovascular/clinical outcome studies with dapagliflozin, and therefore no evidence of beneficial effect, it also seems premature to be using it extensively or considering it as an alternative to the clinically proven metformin.

Comparator clinical trials of surrogate endpoints with albiglutide are in HARMONY

Introduction: Agonists of glucagon-like peptide-1 (GLP-1) receptors are used in the treatment of type 2 diabetes. Albiglutide is a new long acting GLP-1 receptor agonist being developed for once-weekly use. Areas covered: This evaluation is of 2 clinical trials in the HARMONY clinical trials series. HARMONY 3 compares albiglutide to sitagliptin and glimepiride in subjects with type 2 diabetes poorly controlled with metformin, and HARMONY 6 compares albiglutide to insulin lispro in subjects poorly controlled with slow/medium release preparations of insulin. Expert opinion: Both studies showed that albiglutide lowered HbA1c, and had advantages over its comparator drugs. However, questions remain about the safety of albiglutide. Albiglutide is not being used in subjects with a history of thyroid cancer, as it is not known whether this is a rare adverse effect with albiglutide. Also, the safety of albiglutide in subjects with type 2 diabetes and high cardiovascular risk is unknown.