Exenatide Added to Insulin Therapy: A Retrospective Review of Clinical Practice Over Two Years in an Academic Endocrinology Outpatient Setting

Division of Endocrinology and Metabolism, School of Medicine, Indiana University, Indianapolis, Indiana 46202, USA.
Clinical Therapeutics (Impact Factor: 2.73). 07/2009; 31(7):1511-23. DOI: 10.1016/j.clinthera.2009.07.021
Source: PubMed


Background: Exenatide is an antidiabctic agent currently indicated as adjunctive therapy with oral agents for the treatment of type 2 diabetes mellitus (T2DM). Limited published data exist on the off-label use of exenatide in conjunction with insulin in the treatment of T2DM.
The aim of this retrospective study was to examine the effects of exenatide on glycemic control, weight, and insulin dose in patients with T2DM treated with insulin.
Patients with T2DM receivirg insulin and adjuvant therapy with exenatide at an endocrinology clinic at a university hospital for up to 27 months were eligible for inclusion. Glycosylated hemoglobin (HbA(1c)), weight, insulin doses (total, prandial, and basal), concurrent oral antidiabetic medications, and adverse events were ascertained by retrospective review of medical records and were considered the clinical parameters of interest. The last observation in 4 specified time intervals (0-6, 6-12, 12-18, and 18-27 months) for each clinical parameter was used in the analysis.
Of the 3397 patients with a confirmed diagnosis of T2DM who were seen at the clinic during the study period, 268 patients met inclusion criteria and were enrolled in the study. Of the 268 patients enrolled, 38 discontinued therapy within the first 2 months, 30 were lost to follow-up, and 12 did not have evaluable data. These latter patients without sufficient data (n = 42) were not included in the primary analysis but were included in the adverse events analysis. Overall, data from 188 patients (mean [SD] age, 56 (9) years; 85 [45%] men; body mass index, 40.4 [8.4] kg/m(2); 160 [85%] white) were evaluated (mean duration of treatment, 350 [208] days) and included in all analyses. The mean baseline values for HbA(1c), weight, and total daily insulin dose before exenatide therapy were 8.05% (1.47%), 117.8 (24.7) kg, and 99.9 (90.0) U, respectively. For the 4 time intervals, the mean changes in HbA(1c) were: -0.66% (1.54%) at 0 to 6 months (P < 0.001); -0.55% (1.4%) at 6 to 12 months (P < 0.001); -0.54% (1.83%) at 12 to 18 months (P = 0.019); and -0.54% (1.37%) at 18 to 27 months (P = 0.020). Mean weight significantly declined with increasing treatment duration. Mean changes in weight were: -2.4 (5.1) kg at 0 to 6 months (P < 0.001); -4.3 (7.2) kg at 6 to 12 months (P < 0.001); -6.2 (9.7) kg at 12 to 18 months (P < 0.001); and -5.5 (10.8) kg at 18 to 27 months (P < 0.01). After 18 months, an increase in weight was observed; but the increase remained lower than baseline. The mean insulin total daily dose (TDD) was decreased in all patients at the 0- to 6-month (-18.0 [49.9] U; P < 0.001) and the 6- to 12-month (-14.8 [35.3] U; P < 0.001) intervals. Mean changes in insulin TDD during the 12- to 18-month and 18- to 27-month intervals were not statistically significant. The mean percent change from baseline in the basal insulin dose at 0 to 6 months, 6 to 12 months, 12 to 18 months, and 18 to 27 months was not statistically significant. For the 4 intervals, the mean percent change from baseline in the prandial insulin dose was -33.5% (56.2%) at 0 to 6 months (P < 0.001); -25.9% (59.7%) at 6 to 12 months (P = 0.002); -29.7% (74.8%) at 12 to 18 months (P = 0.02); and -55.7% (56.8%) at 18 to 27 months (P = 0.005). Of the 226 patients who were treated with exenatide + insulin for any length of time (including within the first 2 months), 59 (26.1%) discontinued exenatide because of adverse events. The adverse events were largely considered mild and included nausea (n = 51 [22.6% of patients]), vomiting (22 [9.7%]), hypoglycemia (9 [4.0%]), heartburn (2 [0.9%]), diarrhea (1 [0.4%]), constipation (1 [0.4%]), malaise (1 [0.4%]), and generalized edema (1 [0.4%]). Two serious adverse events occurred during the study period: acute renal failure not attributed to exenatide (1 [0.4%]); and pancreatitis (1 [0.4%]), both of which required hospitalization 1 month after the start of exenatide therapy. Conclusion: In this retrospective review of patients with T2DM treated in an outpatient setting, the addition of exenatide to insulin-based therapy was associated with reductions in mean HbA(1c), weight, and prandial insulin requirements for treatment periods of up to 27 months, and in total insulin requirements for treatment periods of up to 12 months.

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    • "The changes thereafter were not statistically significant. The mean prandial insulin dose also decreased from baseline, ranging from –29.7 to –55.7% over 27 months, but with no significant change in basal insulin dose [29]. A greater and significant reduction in total daily dose of 45 U/day (P < 0.001) was reported in the nationwide UK audit [28]. "
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    ABSTRACT: Type 2 diabetes mellitus (T2DM) is a well-recognized risk factor for the development of cardiovascular disease. With an increasing prevalence of obesity, this risk has increased further. Management of T2DM in obese patients is particularly challenging as treatment with the majority of glucose-lowering agents results in weight gain. Thus, the development of a therapeutic option which could improve glycemic control without weight gain or hypoglycemia, such as the glucagon-like peptide-1 (GLP-1) analog exenatide, is a welcome addition to the currently available therapies in the management of T2DM. With recognition and better understanding of the role of incretin hormones in T2DM, exenatide was developed and introduced into clinical practice in 2005. Both randomized controlled trials and retrospective observational studies have shown that treatment with exenatide not only improves glycemic control, with a low risk of hypoglycemia, but also results in concurrent weight loss and the additional benefit of improvement in cardiovascular risk factors. This article will provide an overview of both short- and long-acting exenatide in the management of T2DM and associated cardiovascular risk factors.
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    • "Incretin drugs, on the other hand, lower blood glucose through stimulation of beta-cell function and suppression of glucagon secretion and, in the case of GLP-1RAs, through slowing of gastric emptying. While there are pharmacological arguments for the adoption of incretin therapies earlier in the natural history of T2DM to take advantage of any remaining beta-cell function [19], glycaemic improvements have been shown in insulintreated patients with prolonged duration of diabetes who should have markedly reduced beta-cell function [20] [21] [22] [23]. The antihyperglycaemic effect therefore results from reductions in both postprandial glycaemia (PPG) and FPG—with the latter effect particularly evident with those agents that have a long duration of action. "
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    • "The combined use of glucagon-like peptide 1 (GLP-1) receptor agonists and insulin is of growing clinical interest (1–6), and the combined use of insulin glargine with exenatide is now approved in the U.S. In this recent study, exenatide twice daily added to optimized titration of glargine resulted in greater A1C improvements with weight loss and lesser increase in insulin dose than placebo plus optimized glargine (5). The current exploratory post hoc analysis assessed the relationship of baseline A1C, duration of diabetes, and BMI with glucose control, body weight changes, and insulin doses in that study. "
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    ABSTRACT: To determine variables associated with glycemic and body weight responses when adding exenatide to basal insulin-treated type 2 diabetes. Exploratory subgroup analyses based on baseline A1C, disease duration, and BMI of a 30-week study comparing exenatide twice daily to placebo, added to optimized insulin glargine (intent-to-treat analysis: 137 exenatide; 122 placebo). Exenatide participants had greater A1C reductions compared with optimized insulin glargine alone, irrespective of baseline A1C (P < 0.001). Exenatide participants with longer diabetes duration and those with lower BMI had greater A1C reductions (P < 0.01). Exenatide participants lost more weight, regardless of baseline A1C or BMI (P < 0.05). Exenatide participants with longer diabetes duration lost the most weight (P < 0.001). Exenatide added to optimized basal insulin was associated with improved glycemic control and weight loss, irrespective of baseline A1C, diabetes duration, and BMI. Changes were evident in modestly obese patients and in those with longer diabetes duration.
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