Jenny Han

OBJECTIVE: This study evaluates the ability of the incretin mimetic exenatide (exendin-4) to improve glycemic control in patients with type 2 diabetes failing to achieve glycemic control with maximally effective metformin doses. RESEARCH DESIGN AND METHODS: A triple-blind, placebo-controlled, 30-week study at 82 U.S. sites was performed with 336 randomized patients. In all, 272 patients completed the study. The intent-to-treat population baseline was 53 +/- 10 years with BMI of 34.2 +/- 5.9 kg/m(2) and HbA(1c) of 8.2 +/- 1.1%. After 4 weeks of placebo, subjects self-administered 5 microg exenatide or placebo subcutaneously twice daily for 4 weeks followed by 5 or 10 microg exenatide, or placebo subcutaneously twice daily for 26 weeks. All subjects continued metformin therapy. RESULTS: At week 30, HbA(1c) changes from baseline +/- SE for each group were -0.78 +/- 0.10% (10 microg), -0.40 +/- 0.11% (5 microg), and +0.08 +/- 0.10% (placebo; intent to treat; adjusted P < 0.002). Of evaluable subjects, 46% (10 microg), 32% (5 microg), and 13% (placebo) achieved HbA(1c) < or =7% (P < 0.01 vs. placebo). Exenatide-treated subjects displayed progressive dose-dependent weight loss (-2.8 +/- 0.5 kg [10 microg], -1.6 +/- 0.4 kg [5 microg]; P < 0.001 vs. placebo). The most frequent adverse events were gastrointestinal in nature and generally mild to moderate. Incidence of mild to moderate hypoglycemia was low and similar across treatment arms, with no severe hypoglycemia. CONCLUSIONS: Exenatide was generally well tolerated and reduced HbA(1c) with no weight gain and no increased incidence of hypoglycemia in patients with type 2 diabetes failing to achieve glycemic control with metformin.

OBJECTIVE: This study evaluated the ability of the incretin mimetic exenatide (exendin-4) to improve glycemic control in patients with type 2 diabetes failing maximally effective doses of a sulfonylurea as monotherapy. RESEARCH DESIGN AND METHODS: This was a triple-blind, placebo-controlled, 30-week study conducted at 101 sites in the U.S. After a 4-week, single-blind, placebo lead-in period, 377 subjects were randomized (60% men, age 55 +/- 11 years, BMI 33 +/- 6 kg/m(2), HbA(1c) 8.6 +/- 1.2% [+/-SD]) and began 4 weeks at 5 microg subcutaneous exenatide twice daily (before breakfast and dinner; arms A and B) or placebo. Subsequently, subjects in arm B were escalated to 10 microg b.i.d. exenatide. All subjects continued sulfonylurea therapy. RESULTS: At week 30, HbA(1c) changes from baseline were -0.86 +/- 0.11, -0.46 +/- 0.12, and 0.12 +/- 0.09% (+/-SE) in the 10-microg, 5-microg, and placebo arms, respectively (adjusted P < 0.001). Of evaluable subjects with baseline HbA(1c) > 7% (n = 237), 41% (10 microg), 33% (5 microg), and 9% (placebo) achieved HbA(1c) <or= 7% (P < 0.001). Fasting plasma glucose concentrations decreased in the 10-microg arm compared with placebo (P < 0.05). Subjects in the exenatide arms had dose-dependent progressive weight loss, with an end-of-study loss in the 10-microg exenatide arm of -1.6 +/- 0.3 kg from baseline (P < 0.05 vs. placebo). The most frequent adverse events were generally mild or moderate and gastrointestinal in nature. No severe hypoglycemia was observed. CONCLUSIONS: Exenatide significantly reduced HbA(1c) in patients with type 2 diabetes failing maximally effective doses of a sulfonylurea. Exenatide was generally well tolerated and was associated with weight loss.

This study assessed whether glucose-dependent insulin secretion and overall counterregulatory response are preserved during hypoglycemia in the presence of exenatide. Twelve healthy fasted volunteers were randomized in a triple-blind crossover study to receive either intravenous exenatide (0.066 pmol. kg(-1). min(-1)) or placebo during a 270-min stepwise hyperinsulinemic-hypoglycemic clamp (insulin infusion 0.8 mU. kg(-1). min(-1)). Plasma glucose was clamped sequentially at 5.0 (0-120 min), 4.0 (120-180 min), 3.2 (180-240 min), and 2.7 mmol/l (240-270 min). At 270 min, insulin infusion was terminated and plasma glucose increased to approximately 3.2 mmol/l. The time to achieve plasma glucose >/=4 mmol/l thereafter was recorded. Insulin secretory rates (ISRs) and counterregulatory hormones were measured throughout. Glucose profiles were superimposable between the exenatide and placebo arms. In the presence of euglycemic hyperinsulinemia, ISRs in the exenatide arm were approximately 3.5-fold higher than in the placebo arm (353 +/- 29 vs. 100 +/- 29 pmol/min [least-square means +/- SE]). However, ISRs declined similarly and rapidly at all hypoglycemic steps (</=4 mmol/l) in both groups. Glucagon was suppressed in the exenatide arm during euglycemia and higher than placebo during hypoglycemia. Plasma glucose recovery time was equivalent for both treatments. The areas under the concentration-time curve from 270 to 360 min for cortisol, epinephrine, norepinephrine, and growth hormone were similar between treatment arms. There were no differences in adverse events. In the presence of exenatide, there was a preserved, glucose-dependent insulin secretory response and counterregulatory response during hypoglycemia.

UNLABELLED: It is important for patients that treatments for diabetes not increase cardiovascular (CV) risk. The objective of this analysis was to examine retrospectively the CV safety of exenatide BID, a GLP-1 receptor agonist approved for treating hyperglycemia in patients with type 2 diabetes not adequately controlled with diet and exercise. Individual participant data was pooled to assess the relative risk (RR) of CV events with exenatide BID versus a pooled comparator (PC) group treated with either placebo or insulin from 12 controlled, randomized, clinical trials ranging from 12-52 weeks. Mean baseline values for HbA1c (8.33-8.38%), BMI (31.3-31.5 kg/m2), and duration of diabetes (8 y) were similar between groups. Trials included patients with histories of microvascular and/or macrovascular disease. Customized primary major adverse CV events (MACE) included stroke, myocardial infarction, cardiac mortality, acute coronary syndrome, and revascularization procedures. The Primary MACE RR (0.7; 95% CI 0.38, 1.31), calculated by the Mantel-Haenszel method (stratified by study), suggested that exenatide use (vs. PC) did not increase CV risk; this result was consistent across multiple analytic methods. Because the trials were not designed to assess CV outcomes, events were identified retrospectively from a list of preferred terms by physicians blinded to treatment. Other limitations included the low number of CV events, the short duration of trials (≤1 y), and a single active comparator (insulin). The results of these analyses are consistent with those of a recent retrospective analysis of a large insurance database that found that patients treated with exenatide twice daily were less likely to have a CV event than were patients treated with other glucose-lowering therapies. KEYWORDS: GLP-1 receptor agonist, diabetes, cardiovascular safety.