Jaret Malloy

Efficacy and safety of exenatide once weekly versus sitagliptin or pioglitazone as an adjunct to metformin for treatment of type 2 diabetes (DURATION-2): a randomised trial

BACKGROUND Most patients with type 2 diabetes begin pharmacotherapy with metformin, but eventually need additional treatment. We assessed the safety and efficacy of once weekly exenatide, a glucagon-like peptide 1 receptor agonist, versus maximum approved doses of the dipeptidyl peptidase-4 inhibitor, sitagliptin, or the thiazolidinedione, pioglitazone, in patients treated with metformin. METHODS In this 26-week randomised, double-blind, double-dummy, superiority trial, patients with type 2 diabetes who had been treated with metformin, and at baseline had mean glycosylated haemoglobin (HbA(1c)) of 8.5% (SD 1.1), fasting plasma glucose of 9.1 mmol/L (2.6), and weight of 88.0 kg (20.1), were enrolled and treated at 72 sites in the USA, India, and Mexico. Patients were randomly assigned to receive: 2 mg injected exenatide once weekly plus oral placebo once daily; 100 mg oral sitagliptin once daily plus injected placebo once weekly; or 45 mg oral pioglitazone once daily plus injected placebo once weekly. Primary endpoint was change in HbA(1c) between baseline and week 26. Analysis was by intention to treat, for all patients who received at least one dose of study drug. This trial is registered with ClinicalTrials.gov, number NCT00637273. FINDINGS 170 patients were assigned to receive once weekly exenatide, 172 to receive sitagliptin, and 172 to receive pioglitazone. 491 patients received at least one dose of study drug and were included in the intention-to-treat analysis (160 on exenatide, 166 on sitagliptin, and 165 on pioglitazone). Treatment with exenatide reduced HbA(1c) (least square mean -1.5%, 95% CI -1.7 to -1.4) significantly more than did sitagliptin (-0.9%, -1.1 to -0.7) or pioglitazone (-1.2%, -1.4 to -1.0). Treatment differences were -0.6% (95% CI -0.9 to -0.4, p<0.0001) for exenatide versus sitagliptin, and -0.3% (-0.6 to -0.1, p=0.0165) for exenatide versus pioglitazone. Weight loss with exenatide (-2.3 kg, 95% CI-2.9 to -1.7) was significantly greater than with sitagliptin (difference -1.5 kg, 95% CI -2.4 to -0.7, p=0.0002) or pioglitazone (difference -5.1 kg, -5.9 to -4.3, p<0.0001). No episodes of major hypoglycaemia occurred. The most frequent adverse events with exenatide and sitagliptin were nausea (n=38, 24%, and n=16, 10%, respectively) and diarrhoea (n=29, 18%, and n=16, 10%, respectively); upper-respiratory-tract infection (n=17, 10%) and peripheral oedema (n=13, 8%) were the most frequent events with pioglitazone. INTERPRETATION The goal of many clinicians who manage diabetes is to achieve optimum glucose control alongside weight loss and a minimum number of hypoglycaemic episodes. Addition of exenatide once weekly to metformin achieved this goal more often than did addition of maximum daily doses of either sitagliptin or pioglitazone. FUNDING Amylin Pharmaceuticals and Eli Lilly.

DURATION-5: exenatide once weekly resulted in greater improvements in glycemic control compared with exenatide twice daily in patients with type 2 diabetes.

CONTEXT We wanted to understand the effects of once-weekly vs. twice-daily glucagon-like peptide-1 receptor agonism for treatment of patients with type 2 diabetes. OBJECTIVE The objective of the study was to compare effects of exenatide once weekly (ExQW) and exenatide twice daily (ExBID) on glycemic control, body weight, and safety. DESIGN This was a 24-wk, randomized, open-label, comparator-controlled study. SETTING The study was conducted at 43 sites in the United States. PATIENTS The study population was 252 intent-to-treat patients with type 2 diabetes [baseline (mean ± SD): glycosylated hemoglobin (HbA1c) 8.4 ± 1.2%, fasting plasma glucose 171 ± 47 mg/dl, weight 96 ± 20 kg] that were drug naïve (19%) or previously treated with one (47%) or multiple (35%) oral antidiabetic medications. INTERVENTIONS Interventions included ExQW 2 mg for 24 wk or ExBID 5 μg for 4 wk followed by ExBID 10 μg for 20 wk. MAIN OUTCOME MEASURE The change in HbA1c from baseline to wk 24 was measured. RESULTS At 24 wk, ExQW produced significantly greater changes from baseline (least squares mean ± SE) vs. ExBID in HbA1c (-1.6 ± 0.1% vs. -0.9 ± 0.1%; P < 0.0001) and fasting plasma glucose (-35 ± 5 mg/dl vs. -12 ± 5 mg/dl; P = 0.0008). Similar reductions in mean body weight from baseline to wk 24 were observed in both groups (-2.3 ± 0.4 kg and -1.4 ± 0.4 kg). Both treatments were generally well tolerated. Transient and predominantly mild to moderate nausea, the most frequent adverse event, was less common with ExQW (14%) than with ExBID (35%). Injection-site reactions were infrequent, but more common with ExQW. No major hypoglycemia occurred. CONCLUSIONS Continuous glucagon-like peptide-1 receptor agonism with ExQW resulted in superior glycemic control, with less nausea, compared with ExBID in patients with type 2 diabetes. Both groups lost weight.

DURATION-2: efficacy and safety of switching from maximum daily sitagliptin or pioglitazone to once-weekly exenatide

Diabet. Med. 28, 705–714 (2011)

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.

Efficacy, Safety, and Tolerability of Exenatide Once Weekly in Patients With Type 2 Diabetes Mellitus: An Integrated Analysis of the DURATION Trials

Abstract Background and Aim: Exenatide is a glucagon-like peptide-1 receptor agonist demonstrated to improve glycemic control with low hypoglycemia risk in patients with type 2 diabetes mellitus. The Diabetes Therapy Utilization: Researching Changes in A1C, Weight, and Other Factors Through Intervention With Exenatide Once Weekly (DURATION) program comprised 6 randomized, comparator-controlled, 24- to 30-week trials of exenatide once weekly (EQW), an extended-release formulation. This post hoc analysis pooled data from patients taking EQW across 6 trials to assess efficacy and safety in a large, varied patient population. Materials and Methods: The intent-to-treat (ITT) population contained 1379 patients (baseline mean ± standard deviation glycated hemoglobin [HbA1c] levels of 8.4% ± 1.1%) who were treated with EQW over the course of 24 to 30 weeks. Changes from baseline in efficacy parameters for the ITT population and a completer population (1195 patients with ≥ 22 weeks of exposure) were evaluated. Results: The ITT population experienced significant reductions from baseline (least-squares mean [95% CI]) in HbA1c levels (−1.4% [−1.5% to −1.4%]), fasting blood glucose levels (−36 mg/dL [−38.4 mg/dL to −33.8 mg/dL]), and body weight (−2.5 kg [−2.8 kg to −2.3 kg]) after 24 to 30 weeks of EQW treatment. Reductions in HbA1c and fasting blood glucose levels were observed across baseline HbA1c, level strata; patients with higher baseline HbA1c levels experienced greater reductions. Treatment with EQW was associated with modest, significant reductions in blood pressure (systolic blood pressure, −2.8 mm Hg [−3.5 mm Hg to −2.1 mm Hg]; diastolic blood pressure, −0.8 mm Hg [−1.2 mm Hg to −0.4 mm Hg]), and fasting lipid levels (total cholesterol, −6.5 mg/dL [−8.2 mg/dL to −4.7 mg/dL]; low-density lipoprotein cholesterol, −3.9 mg/dL [5.3 mg/dL to −2.5 mg/dL]; and triglyceride [geometric least-squares mean percent change (95% CI)], −6% [−8% to −4%] levels). Similar reductions were observed in the completer population. Exenatide once weekly was generally well tolerated. Transient, mild-to-moderate gastrointestinal treatment-emergent adverse events and injection-site treatment-emergent adverse events were reported most frequently, but were seldom treatment limiting. No major hypoglycemic events were observed; minor hypoglycemic events occurred infrequently in patients not using a sulfonylurea. Conclusion: This post hoc analysis of > 1300 patients demonstrated that EQW was associated with significant reductions in HbA1c levels, body weight, blood pressure, and fasting lipid levels, with minimal hypoglycemia risk. Consistent with established safety profiles, EQW therapy was generally well tolerated., Trial registration: www.ClinicalTrials.gov identifiers: NCT00308139, NCT00637273, NCT00641056, NCT00676338, NCT00877890, NCT01029886

Exenatide at therapeutic and supratherapeutic concentrations does not prolong the QTc interval in healthy subjects

Aims Exenatide has been demonstrated to improve glycaemic control in patients with type 2 diabetes, with no effect on heart rate corrected QT (QTc) at therapeutic concentrations. This randomized, placebo- and positive-controlled, crossover, thorough QT study evaluated the effects of therapeutic and supratherapeutic exenatide concentrations on QTc. Methods Intravenous infusion was employed to achieve steady-state supratherapeutic concentrations in healthy subjects within a reasonable duration (i.e. days). Subjects received exenatide, placebo and moxifloxacin, with ECGs recorded pre-therapy and during treatment. Intravenous exenatide was expected to increase heart rate to a greater extent than subcutaneous twice daily or once weekly formulations. To assure proper heart rate correction, a wide range of baseline heart rates was assessed and prospectively defined methodology was applied to determine the optimal QT correction. Results Targeted steady-state plasma exenatide concentrations were exceeded (geometric mean ± SEM 253 ± 8.5 pg ml−1, 399 ± 11.9 pg ml−1 and 627 ± 21.2 pg ml−1). QTcP, a population-based method, was identified as the most appropriate heart rate correction and was prespecified for primary analysis. The upper bound of the two-sided 90% confidence interval for placebo-corrected, baseline-adjusted QTcP (ΔΔQTcP) was <10 ms at all time points and exenatide concentrations. The mean of three measures assessed at the highest steady-state plasma exenatide concentration of ∼500 pg ml−1 (ΔΔQTcPavg) was −1.13 [−2.11, −0.15). No correlation was observed between ΔΔQTcP and exenatide concentration. Assay sensitivity was confirmed with moxifloxacin. Conclusions These results demonstrated that exenatide, at supratherapeutic concentrations, does not prolong QTc and provide an example of methodology for QT assessment of drugs with an inherent heart rate effect.

Pharmacology and Tolerability of a Single Dose of Exenatide in Adolescent Patients With Type 2 Diabetes Mellitus Being Treated With Metformin: A Randomized, Placebo-Controlled, Single-Blind, Dose-Escalation, Crossover Study

OBJECTIVE This study assessed the pharmacokinetics, pharmacodynamics, and tolerability of single doses of exenatide in adolescent patients with type 2 diabetes mellitus (T2DM). METHODS This was a randomized, single-blind, dose-escalation, crossover study in adolescent (age 10-16 years) patients with T2DM who were being treated with diet and exercise or a stable dose of metformin, a sulfonylurea, or a combination of metformin and a sulfonylurea for at least 3 months before screening. Eligible patients were allocated to receive single subcutaneous doses of exenatide 2.5 microg, exenatide 5 microg, and placebo, each followed by a standardized meal, on 3 separate days (maximum interval between first and third doses, 5 weeks). Exenatide 2.5 microg always preceded exenatide 5 microg in each treatment sequence. The primary end points were the pharmacokinetics and safety profile of exenatide; secondary end points included postprandial plasma glucose, serum insulin, and plasma glucagon concentrations. RESULTS The study enrolled 13 adolescent patients with T2DM (7 females, 6 males; mean [SD] age, 15 [1] years; body mass index, 32.5 [5.0] kg/m(2); glycosylated hemoglobin, 8.2% [1.5%]). After administration of exenatide 5 microg, the geometric mean (SE) exenatide AUC(0-infinity) and C(max) were 339.5 (39.6) pg * h/mL and 85.1 (11.5) pg/mL, respectively (n = 12). The exenatide AUC appeared to be dose dependent, although exenatide was not quantifiable in all patients at the 2.5-microg dose; after administration of exenatide 2.5-microg, the geometric mean AUC(0-infinity)) was 159.2 (23.1) pg * h/mL (n = 6) and the geometric mean C(max) was 56.3 (10.1) pg/mL (n = 9). Both exenatide doses were associated with significant reductions in postprandial plasma glucose excursions compared with placebo (P < 0.01); the incremental mean (SE) AUC(15-360min) was -3465.6 (1587.3) mg * min/dL for exenatide 2.5 pg, -4422.2 (2434.4) mg * min/dL for exenatide 5 microg, and 3457.4 (1615.5) mg * min/dL for placebo. The 2 exenatide doses were also associated with significant reductions in postprandial plasma glucagon concentrations compared with placebo (P < 0.01); the respective incremental mean values for AUC(15-180min) were 125.5 (658.4), -1403.8 (632.1), and 1843.1 (540.6) pg * min/mL. There were no significant differences in serum insulin concentrations between exenatide and placebo. Exenatide was generally well tolerated, with no hypoglycemic events recorded during the study. CONCLUSIONS In these adolescent patients with T2DM, administration of single 2.5- and 5-microg doses of exenatide were associated with dose-dependent increases in plasma exenatide concentrations and improved postprandial glucose concentrations compared with placebo. Both doses appeared to be well tolerated. ClinicalTrials.gov Identifier: NCT00254254.

Increased variability and abnormalities in pancreatic enzyme concentrations in otherwise asymptomatic subjects with type 2 diabetes

Background Recent studies have demonstrated an increased incidence of pancreatitis in patients with type 2 diabetes compared with obese nondiabetic individuals. Serum lipase and pancreatic amylase concentrations are used in conjunction with clinical findings to diagnose pancreatitis. Methods In two large clinical trials of overweight/obese nondiabetic and type 2 diabetic subjects, lipase and pancreatic amylase were measured at screening and 2–5 weeks later at baseline (prior to treatment with study medication). Results Lipase and pancreatic amylase concentrations were above the upper limit of normal (ULN) in 13% and 6% of type 2 diabetic subjects, respectively, and were approximately three-fold (3 ×) higher than the proportion of nondiabetic subjects with levels above ULN. Elevations exceeding ULN were seen in many subjects asymptomatic for pancreatitis; however, elevations >2 × ULN and >3 × ULN were uncommon, and elevations >3 × ULN were often associated with a history of dyslipidemia, hyperlipidemia, and gastrointestinal disorders. Additionally, enzyme concentrations varied within this 2–5-week screening period, including shifts between elevated and normal levels. Conclusion Results from this post hoc analysis suggest that, although pancreatic enzymes can be a useful marker for pancreatitis within the proper clinical context, diagnosis of pancreatitis may be confounded in populations known to have asymptomatic elevations associated with disease, such as type 2 diabetes. Further effort is needed to clarify the etiology and epidemiology of pancreatic enzyme elevations in type 2 diabetes.

Safety and tolerability of exenatide once weekly in patients with type 2 diabetes: an integrated analysis of 4,328 patients

Background Exenatide once weekly (QW) is a glucagon-like peptide-1 receptor agonist (GLP-1RA) for the treatment of type 2 diabetes. Safety and tolerability are key considerations in treatment selection. This analysis examines the safety and tolerability profile of exenatide QW, other approved GLP-1RAs (exenatide twice daily and liraglutide once daily), and a pooled population of commonly used non-GLP-1RA treatments. Methods Intent-to-treat populations from eight randomized Phase III trials with 24-week and 30-week comparator-controlled periods were analyzed. Data were pooled for exenatide QW, exenatide twice daily, and non-GLP-1RA comparator groups; comparisons between exenatide QW and liraglutide were analyzed separately to better match study groups. The incidence of treatment-emergent adverse events with 95% confidence intervals and exposure-adjusted incidence were calculated. Duration and recurrence were analyzed for gastrointestinal adverse events and adverse events of special interest. Results Incidences of serious adverse events did not differ between treatments. Discontinuations due to adverse events occurred numerically less frequently with exenatide QW than with other GLP-1RAs but numerically more frequently than with non-GLP-1RA comparators. The most frequent adverse events in the GLP-1RA groups were gastrointestinal and generally mild, with decreasing incidence over time. Gastrointestinal adverse event incidences appeared lower with exenatide QW versus other GLP-1RAs and greater than with non-GLP-1RA comparators. Injection site-related adverse events seemed highest with exenatide QW, but generally did not lead to withdrawal and abated over time. Hypoglycemia was infrequent overall, but occurred numerically more frequently in the non-GLP-1RA comparator group and increased with concomitant sulfonylurea use. Pancreatitis, thyroid cancer, renal failure, and gallbladder disease were rarely reported. Conclusion The overall safety and tolerability profile of exenatide QW was similar to that of other GLP-1RAs, with improved gastrointestinal tolerability. The safety and tolerability profile of exenatide QW compared with non-GLP-1RA comparators was similar overall, with the exception of a lower incidence of hypoglycemia and anticipated differences in gastrointestinal and injection site-related adverse events.

Effects of MetAP2 inhibition on hyperphagia and body weight in Prader-Willi syndrome: A randomized, double-blind, placebo-controlled trial

There are no treatments for the extreme hyperphagia and obesity in Prader–Willi syndrome (PWS). The bestPWS clinical trial assessed the efficacy, safety and tolerability of the methionine aminopeptidase 2 (MetAP2) inhibitor, beloranib.