EXSCEL
PubMed • Full text • PDF • ClinicalTrials.gov
Clinical Question
In patients with type 2 diabetes with or without previous CVD, does weekly extended-release (ER) exenatide reduce the occurrence of death from cardiovascular causes when compared to placebo?
Bottom Line
Among adults with type 2 diabetes with or without prior CVD, use of exenatide ER (a GLP-1 agonist) was not associated with a reduction in CVD events when compared with placebo. There were numerically fewer composite CVD events in the exenatide group, however, and the non-significant trend towards benefit is consistent with findings of CVD event reduction seen in other GLP-1 agonist trials (e.g., liraglutide in LEADER, semaglutide in SUSTAIN-6).
Major Points
Diabetes is a risk factor for CVD.[1] Liraglutide is a GLP-1 agonist that lowers blood sugar, BP, and promotes weight loss. Other GLP-1 agonists were found to lower CVD event rates, such as liraglutide in 2016's LEADER trial and semaglutide in 2016's SUSTAIN-6 trial. Whether exenatide, a different GLP-1 agonist, also lowered CVD events in type 2 diabetes was unknown.
Published in EXenatide Study of Cardiovascular Event Lowering (EXSCEL) trial randomized 14,752 patients with diabetes (~73% with prior CVD events) to exenatide or placebo. At a median of 3.2 years, there was no significance difference between the two arms, though there were numerically fewer composite CVD events in the exenatide arm (11.4% vs 12.2%; HR 0.91; 95% CI 0.83-1.00; P=0.06). The effect size is in the same direction as was seen in LEADER and SUSTAIN-6.
Guidelines
As of October 2017, no guidelines have been published that reflect the results of this trial. Current AACE guidelines recommend GLP-1R agonists as first line, non-insulin therapy for intensifying prandial control for Type 2 Diabetes patients.
Design
- Randomized, double blind, placebo-controlled, multicenter event-driven trial
- N=14,752
- Exenatide ER (n=7,356)
- Placebo (n=7,396)
- Setting: 687 sites in 35 countries
- Enrollment: 2010-2015
- Median follow-up: 5 months
- Analysis: Intention-to-treat
- Primary outcome: Death from cardiovascular causes: Non-fatal myocardial infarction, or non-fatal stroke.
Population
Inclusion Criteria
- T2DM and Hgb A1c 6.5-10.0%
- Age ≥18 years, with or without previous cardiovascular events
- Eligible previous cardiovascular events:
- History of major clinical manifestation of coronary artery disease
- Ischemic cerebrovascular disease
- Atherosclerotic peripheral arterial disease
Exclusion Criteria
- History of two or more episodes of severe hypoglycemia
- Defined as: Hypoglycemia which the patient required 3rd party assistance in the preceding 12 months
- History of major clinical manifestation of coronary artery disease
- End-stage kidney disease
- Estimated glomerular filtration rate (eGFR) at entry of less than 30 mL/min/1.73m2
- A personal or family history of:
- Medullary thyroid carcinoma
- Multiple endocrine neoplasia
- Baseline calcitonin level of greater than 40 ng/L
- Previous treatment with a GLP-1 receptor agonist
Baseline Characteristics
Presented in the order of treatment vs placebo
- Age
- < 65: 60% vs 60%
- ≥ 65: 40% vs 40%
- Sex
- Male: 62% vs 62%
- Female: 38% vs 38%
- Race or Ethnic Group
- White: 75.5% vs 76%
- Black: 6% vs 5.9%%
- Asian: 9.9% vs 9.8%
- Native American/Alaskan Native: 0.05% vs 0.05%
- Pacific Islander: 0.02% vs 0.02%
- Hispanic: 7.8% vs 7.5%
- Region
- Europe: 46% vs 46%
- North America: 25% vs 25.3%
- Latin America: 18.5% vs 18.4%
- Asia-Pacific: 10.5% vs 10.3%
Interventions
- Open label glucose-lowering agents use, excluding GLP-1R agonists, were encouraged in each group in order to help patients achieve goal glycated hemoglobin targets. Patients were randomly assigned into a 1:1 ratio into the following groups:
- Subcutaneous injections of extended-release exenatide at a dose of 2 mg, once weekly.
- Placebo
Outcomes
Comparisons are once weekly exenatide ER injections vs. Placebo.
Primary Outcome
- Death from cardiovascular causes, nonfatal myocardial infarction, or nonfatal stroke
- 11.4% vs 12.2% (HR 0.91; 95% CI 0.83-1.00; P=0.06)
Secondary Outcomes
- Death from any cause
- 6.9% vs 7.9% (HR 0.86; 95% CI 0.77-0.97)
- Not considered statistically significant on the basis of hierarchical testing
- Death from cardiovascular causes, including unknown causes
- 4.6% vs 5.2% (HR 0.88; 95% CI 0.76-1.02)
- Fatal or nonfatal myocardial infarction
- 6.6% vs 6.7% (HR 0.97; 95% CI 0.85-1.10)
- Fatal or nonfatal stroke
- 2.5% vs 2.9% (HR 0.85; 95% CI 0.70-1.03)
- Hospitalization for heart failure
- 3.0% vs 3.1% (HR 0.94; 95% CI 0.78-1.13)
- Hospitalization for acute coronary syndrome
- 8.2% vs 7.7% (HR 1.05; 95% CI 0.94-1.18)
Subgroup Analysis
A subgroup analysis was performed on the duration in which individuals had diabetes, use of anti-hyperglycemic oral agents, insulin therapy, DPP-4 inhibitors, history of congestive heart failure, glycated hemoglobin levels below and above/equal to 8%, estimated GFR, body-mass index, and previous cardiovascular events at randomization. Each group was shown to be non-significant in nature.
Adverse Events
Authors did not provide statistical analysis on the adverse events, but note the treatment group was equivalent to placebo with respect to safety.
Criticisms
- Follow up time was limited to a median of 5 months.
- The LEADER trial, with significant cardioprotective findings, had a median follow up of 3.8 years. In relation, this 5 month follow up is unlikely to provide sufficient time to evaluate the benefits of exenatide ER on cardiovascular events.
- Liraglutide is more homologous to human GLP-1, than exenatide as it is obtained from a reptile.
- There has not been a comparison to determine whether or not the homology of the medication affects the therapeutic profile of the medications.
- Although other diabetes medications were shown, the use of other cardioprotective medication was not disclosed.
Funding
Funded by Amylin Pharmaceuticals.