The design and rationale for the Acute Medically Ill Venous Thromboembolism Prevention with Extended Duration Betrixaban (APEX) study.

Randomized clinical trials have identified a population of acute medically ill patients who remain at risk for venous thromboembolism (VTE) beyond the standard duration of therapy and hospital discharge. The aim of the APEX study is to determine whether extended administration of oral betrixaban (35-42 days) is superior to a standard short course of prophylaxis with subcutaneous enoxaparin (10 ± 4 days followed by placebo) in patients with known risk factors for post-discharge VTE. Patients initially are randomized to receive either betrixaban or enoxaparin (and matching placebo) in a double dummy design. Following a standard duration period of enoxaparin treatment (with placebo tablets) or betrixaban (with placebo injections), patients receive only betrixaban (or alternative matching placebo). Patients are considered for enrollment if they are older than 40 years, have a specified medical illness, and restricted mobility. They must also meet the APEX criteria for increased VTE risk (aged ≥75 years, baseline D-Dimer ≥2× upper the limit of "normal", or 2 additional ancillary risk factors for VTE). The primary efficacy end point is the composite of asymptomatic proximal deep venous thrombosis, symptomatic deep venous thrombosis, non-fatal (pulmonary embolus) pulmonary embolism, or VTE-related death through day 35. The primary safety outcome is the occurrence of major bleeding. We hypothesize that extended duration betrixaban VTE prophylaxis will be safe and more effective than standard short duration enoxaparin in preventing VTE in acute medically ill patients with known risk factors for post hospital discharge VTE.

Edifoligide and long-term outcomes after coronary artery bypass grafting: PRoject of Ex-vivo Vein graft ENgineering via Transfection IV (PREVENT IV) 5-year results.

BACKGROUND: Edifoligide, an E2F transcription factor decoy, does not prevent vein graft failure or adverse clinical outcomes at 1 year in patients undergoing coronary artery bypass grafting (CABG). We compared the 5-year clinical outcomes of patients in PREVENT IV treated with edifoligide and placebo to identify predictors of long-term clinical outcomes. METHODS: A total of 3,014 patients undergoing CABG with at least 2 planned vein grafts were enrolled. Kaplan-Meier curves were generated to compare the long-term effects of edifoligide and placebo. A Cox proportional hazards model was constructed to identify factors associated with 5-year post-CABG outcomes. The main outcome measures were death, myocardial infarction (MI), repeat revascularization, and rehospitalization through 5 years. RESULTS: Five-year follow-up was complete in 2,865 patients (95.1%). At 5 years, patients randomized to edifoligide and placebo had similar rates of death (11.7% and 10.7%, respectively), MI (2.3% and 3.2%), revascularization (14.1% and 13.9%), and rehospitalization (61.6% and 62.5%). The composite outcome of death, MI, or revascularization occurred at similar frequency in patients assigned to edifoligide and placebo (26.3% and 25.5%, respectively; hazard ratio 1.03 [95% CI 0.89-1.18], P = .721). Factors associated with death, MI, or revascularization at 5 years included peripheral and/or cerebrovascular disease, time on cardiopulmonary bypass, lung disease, diabetes mellitus, and congestive heart failure. CONCLUSIONS: Up to a quarter of patients undergoing CABG will have a major cardiac event or repeat revascularization procedure within 5 years of surgery. Edifoligide does not affect outcomes after CABG; however, common identifiable baseline and procedural risk factors are associated with long-term outcomes after CABG.

Rationale and design of the Acute Study of Clinical Effectiveness of Nesiritide in Decompensated Heart Failure Trial (ASCEND-HF).

BACKGROUND: Acute decompensated heart failure (ADHF) is a major public health burden with significant mortality and morbidity. Nesiritide is a recombinantly produced intravenous formulation of human B-type natriuretic peptide that promotes vasodilation and increases salt and water excretion, which results in reduced cardiac filling pressures. Prior studies have shown that dyspnea is improved in patients with ADHF 3 hours after nesiritide infusion with significant dose-related reductions in cardiac filling pressures and systemic vascular resistance without significant arrhythmias. However, the effect of nesiritide on dyspnea at 6 or 24 hours is unknown, and no clinical outcome trials have been done to provide a reliable estimate of the effect of nesiritide on morbidity and mortality. METHODS: The Acute Study of Clinical Effectiveness of Nesiritide in Decompensated Heart Failure trial (ASCEND-HF) is a phase III study evaluating the efficacy and safety of nesiritide in patients with ADHF. Patients hospitalized for hear failure will be randomly assigned to receive either intravenous nesiritide or matching placebo for 24 hours to 7 days. The 2 coprimary end points are (1) assessment of acute dyspnea at 6 or 24 hours and (2) death or rehospitalization for hear failure within 30 days. A total of 7,000 patients will be enrolled worldwide between 2007 and 2010. CONCLUSIONS: The data from the ASCEND-HF trial will establish whether nesiritide safely improves acute dyspnea as well as morbidity and mortality at 30 days.

Is glycoprotein IIb/IIIa antagonism as effective in women as in men following percutaneous coronary intervention?. Lessons from the ESPRIT study.

OBJECTIVE: The study was done to determine whether eptifibatide, a platelet glycoprotein (GP) IIb/IIIa antagonist, prevents ischemic complications following percutaneous coronary interventions (PCIs) in women as well as in men. BACKGROUND: Eptifibatide reduces ischemic complications after nonurgent coronary stent interventions. METHODS: We compared outcomes in women (n = 562) and men (n = 1,502) enrolled in the Enhanced Suppression of the Platelet GP IIb/IIIa Receptor with Integrilin Therapy (ESPRIT) trial of double-bolus eptifibatide during PCI. RESULTS: Women in the ESPRIT trial were older, and more frequently had hypertension, diabetes mellitus, or acute coronary syndromes, but were less likely to have prior PCI or coronary artery bypass graft surgery. The primary end point, a composite at 48 h of death, myocardial infarction (MI), urgent target vessel revascularization (TVR), and unplanned GP IIb/IIIa use, occurred in 10.5% of women and 7.9% of men (p = 0.082). The composite of death, MI, or TVR after one year occurred in 24.5% of women compared with 18% of men (p = 0.0008). At 48 h, eptifibatide reduced the composite of death, MI, and TVR from 14.5% to 6.0% in women versus 9.0% to 6.8% in men. At one year, these differences persisted: 28.9% versus 20.0% for women and 19.5% versus 16.6% for men. No statistical interaction existed between treatment and gender at either 48 h (p = 0.063) or one year (p = 0.2). Bleeding occurred more commonly in women (5.5% vs. 2.6%, p = 0.002), and was more common in eptifibatide-treated women. After adjustment for age, weight, and hypertension, no interaction between treatment and gender was present. CONCLUSION: Eptifibatide is effective to prevent ischemic complications of PCI in women and may eliminate gender-related differences in PCI outcomes.

The PRoject of Ex-vivo Vein graft ENgineering via Transfection IV (PREVENT IV) trial: study rationale, design, and baseline patient characteristics.

BACKGROUND: Coronary artery bypass graft (CABG) surgery with autologous vein graft (VG) conduit is one of the most frequently performed operations in the United States. Unfortunately, many VGs become occluded during long-term follow-up largely because of neointimal hyperplasia. A novel approach to preventing neointimal hyperplasia is with the double-stranded oligonucleotide edifoligide (Corgentech Inc, South San Francisco, Calif). Edifoligide inhibits E2F, a transcription factor that activates cell-cycle genes responsible for neointimal hyperplasia. METHODS: PREVENT IV is a phase-III, multicenter, randomized double-blind placebo-controlled trial of ex vivo treatment of autologous VGs with edifoligide in patients undergoing initial CABG surgery. The primary end point is VG failure, defined as death or > or =75% stenosis in a treated VG at 12- to 18-month angiographic follow-up. Secondary end points include major adverse cardiac events through at least 5 years and adverse events through 30 days. RESULTS: Enrollment of 3014 patients from 107 sites was completed on October 22, 2003. The baseline and procedural characteristics of the PREVENT IV population are generally well matched to a contemporary population of patients undergoing initial CABG from the Society of Thoracic Surgeons National Database. Angiographic follow-up is ongoing and scheduled to be completed in March 2005. CONCLUSIONS: The PREVENT IV data will establish whether VG pretreatment with an E2F transcription factor decoy, edifoligide, can improve graft patency and reduce the long-term morbidity and mortality of patients undergoing CABG surgery.

Relation of early saphenous vein graft failure to outcomes following coronary artery bypass surgery.

Up to 20% of saphenous vein grafts (SVGs) fail within 2 years of coronary artery bypass grafting (CABG). The long-term effects of early SVG failure on major clinical events remain undefined in contemporary patient populations. We sought to examine the relation between early SVG failure and long-term outcomes after CABG. Using the Duke Cardiovascular Databank, we examined baseline clinical and angiographic characteristics and clinical outcomes among patients who underwent catheterization 1 to 18 months after their first CABG from 1986 to 2004. Patients were classified on the basis of their worst SVG stenosis as having no (<25%), noncritical (25% to 74%), critical (75% to 99%), or occlusive (100%) SVG disease. Our primary outcome measure was the composite of death, myocardial infarction, or repeat revascularization after catheterization. Of 1,243 patients included in the analysis, 27.9% had no, 11.9% had noncritical, 20.8% had critical, and 39.3% had occlusive SVG disease. At 10 years, the corresponding adjusted composite event rates were 41.2%, 56.2%, 81.2%, and 67.1%, respectively (p <0.0001). Most events occurred immediately after catheterization in patients with critical and occlusive SVG disease and were primarily repeat revascularization. On multivariate analysis, critical, nonocclusive SVG disease was the strongest predictor of the composite outcome (hazard ratio 2.36, 95% confidence interval 2.00 to 2.79, p <0.0001). In conclusion, in contemporary clinical practice, early SVG failure is associated with worse long-term outcomes after CABG.

Design and rationale of the PREVENT III clinical trial: edifoligide for the prevention of infrainguinal vein graft failure.

Surgical bypass of peripheral arterial occlusive disease with autologous vein grafts provides an effective means of restoring blood flow to the lower extremity, and has been a standard therapy for patients with disabling claudication or critical limb ischemia (CLI). However, failure rates may run as high as 50% within 5 years. These graft failures occur as a result of neointimal hyperplasia, a ubiquitous biologic response of blood vessel walls to injury, which is characterized by the migration and proliferation of smooth muscle cells (SMC). The E2F family of transcription factors regulates the expression of genes controlling SMC proliferation. Edifoligide (E2F Decoy) is a novel therapy that inhibits E2F function, thus attenuating neointimal hyperplasia. Its use in conjunction with a patented drug delivery pressurization chamber is under investigation. Using this system, edifoligide is administered to vein grafts in a single, ex vivo treatment following vein harvest and before implantation, resulting in minimal systemic drug exposure and excellent patient compliance. This Phase 3, randomized, double-blind, multicenter clinical trial is designed to evaluate the safety and efficacy of edifoligide in a population of approximately 1400 patients with CLI undergoing infrainguinal bypass for peripheral arterial disease (PAD). The primary outcome measure will be the time to occurrence of non-technical graft failure resulting in either graft revision or major amputation at 12 months after enrollment. A governing Clinical Events Classification committee (CEC) will adjudicate each graft failure to determine its etiology. The PREVENT III trial is the largest multicenter trial ever performed in patients receiving autologous vein bypass grafts for CLI. This landmark study will determine if edifoligide is safe and effective at preventing vein graft failure in patients undergoing lower extremity bypass, but it also provides a unique opportunity to observe current treatment practices in vascular surgery.

Efficacy and safety of edifoligide, an E2F transcription factor decoy, for prevention of vein graft failure following coronary artery bypass graft surgery: PREVENT IV: a randomized controlled trial.

CONTEXT: Coronary artery bypass graft (CABG) surgery with autologous vein grafting is commonly performed. Progressive neointimal hyperplasia, however, contributes to considerable vein graft failure. Edifoligide is an oligonucleotide decoy that binds to and inhibits E2F transcription factors and thus may prevent neointimal hyperplasia and vein graft failure. OBJECTIVE: To assess the efficacy and safety of pretreating vein grafts with edifoligide for patients undergoing CABG surgery. DESIGN, SETTING, AND PARTICIPANTS: A phase 3 randomized, double-blind, placebo-controlled trial of 3014 patients undergoing primary CABG surgery with at least 2 planned saphenous vein grafts and without concomitant valve surgery, who were enrolled between August 2002 and October 2003 at 107 US sites. INTERVENTION: Vein grafts were treated ex vivo with either edifoligide or placebo in a pressure-mediated delivery system. The first 2400 patients enrolled were scheduled for 12- to 18-month follow-up angiography. MAIN OUTCOME MEASURES: The primary efficacy end point was angiographic vein graft failure (> or =75% vein graft stenosis) occurring 12 to 18 months after CABG surgery. Other end points included other angiographic variables, adverse events through 30 days, and major adverse cardiac events. RESULTS: A total of 1920 patients (80%) either died (n = 91) or underwent follow-up angiography (n = 1829). Edifoligide had no effect on the primary end point of per patient vein graft failure (436 [45.2%] of 965 patients in the edifoligide group vs 442 [46.3%] of 955 patients in the placebo group; odds ratio, 0.96 [95% confidence interval {CI}, 0.80-1.14]; P = .66), on any secondary angiographic end point, or on the incidence of major adverse cardiac events at 1 year (101 [6.7%] of 1508 patients in the edifoligide group vs 121 [8.1%] of 1506 patients in the placebo group; hazard ratio, 0.83 [95% CI, 0.64-1.08]; P = .16). CONCLUSIONS: Failure of at least 1 vein graft is quite common within 12 to 18 months after CABG surgery. Edifoligide is no more effective than placebo in preventing these events. Longer-term follow-up and additional research are needed to determine whether edifoligide has delayed beneficial effects, to understand the mechanisms and clinical consequences of vein graft failure, and to improve the durability of CABG surgery. Clinical Trial Registration ClinicalTrials.gov Identifier: NCT00042081.

Relationship of creatine kinase-myocardial band release to Thrombolysis in Myocardial Infarction perfusion grade after intracoronary stent placement: an ESPRIT substudy.

BACKGROUND: The etiology of creatine kinase-myocardial band (CK-MB) release after percutaneous coronary intervention (PCI) remains unclear. The goal of this study was to evaluate the relationship of both epicardial and tissue level perfusion at the completion of stent placement to CK-MB release after the procedure. Given the high rates of Thrombolysis in Myocardial Infarction (TIMI) grade 3 flow after PCI, we hypothesized that abnormalities in tissue level perfusion would instead explain CK-MB release. METHODS: Data were drawn from the angiographic substudy of the Enhanced Suppression of the Platelet IIb/IIIa Receptor With Integrilin Therapy (ESPRIT) trial of eptifibatide versus placebo in patients undergoing planned coronary stent implantation. In the substudy, cinefilms of 65 patients were analyzed by an angiographic core laboratory blinded to enzymatic and clinical outcomes. RESULTS: The release of CK-MB was not associated with TIMI grade 3 flow or the corrected TIMI frame count; 100% of patients had TIMI grade 3 flow at the completion of PCI. In contrast, tissue level perfusion using the TIMI myocardial perfusion grade (TMPG) was related to postintervention CK-MB release: patients with a closed myocardium (TMPG 0/1) or delayed myocardial perfusion (TMPG 2) had an average CK-MB release 2.2 +/- 2.7 times the upper limit of normal (n = 34), whereas those patients with normal myocardial perfusion (TMPG 3, n = 24) had CK-MB 0.8 +/- 0.6 times the upper limit of normal (P =.01). Although no patients with TMPG 3 sustained death/myocardial infarction/urgent target vessel revascularization or thrombotic bailout, 17.7% of patients with TMPG 0/1/2 did by 48 hours (P =.037). CONCLUSIONS: Impaired tissue level perfusion as assessed by the TMPG and not epicardial coronary blood flow is associated with CK-MB elevation after PCI. These data provide a pathophysiologic link between impaired tissue level perfusion, post-PCI infarction, and adverse clinical outcomes.

Results of PREVENT III: a multicenter, randomized trial of edifoligide for the prevention of vein graft failure in lower extremity bypass surgery.

OBJECTIVE: The PREVENT III study was a prospective, randomized, double-blinded, multicenter phase III trial of a novel molecular therapy (edifoligide; E2F decoy) for the prevention of vein graft failure in patients undergoing infrainguinal revascularization for critical limb ischemia (CLI). METHODS: From November 2001 through October 2003, 1404 patients with CLI were randomized to a single intraoperative ex vivo vein graft treatment with edifoligide or placebo. After surgery, patients underwent graft surveillance by duplex ultrasonography and were followed up for index graft and limb end points to 1 year. A blinded Clinical Events Classification committee reviewed all index graft end points. The primary study end point was the time to nontechnical index graft reintervention or major amputation due to index graft failure. Secondary end points included all-cause graft failure, clinically significant graft stenosis (>70% by angiography or severe stenosis by ultrasonography), amputation/reintervention-free survival, and nontechnical primary graft patency. Event rates were based on Kaplan-Meier estimates. Time-to-event end points were compared by using the log-rank test. RESULTS: Demographics, comorbidities, and procedural details reflected a population with CLI and diffuse atherosclerosis. Tissue loss was the presenting symptom in 75% of patients. High-risk conduits were used in 24% of cases, including an alternative vein in 20% (15% spliced vein and 5% non-great saphenous vein) and 6% less than 3 mm in diameter; 14% of the cases were reoperative bypass grafts. Most (65%) grafts were placed to infrapopliteal targets. Perioperative (30-day) mortality occurred in 2.7% of patients. Major morbidity included myocardial infarction in 4.7% and early graft occlusion in 5.2% of patients. Ex vivo treatment with edifoligide was well tolerated. There was no significant difference between the treatment groups in the primary or secondary trial end points, primary graft patency, or limb salvage. A statistically significant improvement was observed in secondary graft patency (estimated Kaplan-Meier rates were 83% edifoligide and 78% placebo; P = .016) within 1 year. The reduction in secondary patency events was manifest within 30 days of surgery (the relative risk for a 30-day event for edifoligide was 0.45; 95% confidence interval, 0.27-0.76; P = .005). For the overall cohort at 1 year, the estimated Kaplan-Meier rate for survival was 84%, that for primary patency was 61%, that for primary assisted patency was 77%, that for secondary patency was 80%, and that for limb salvage was 88%. CONCLUSIONS: In this prospective, randomized, placebo-controlled clinical trial, ex vivo treatment of lower extremity vein grafts with edifoligide did not confer protection from reintervention for graft failure.

Ethics and equipoise: rationale for a placebo-controlled study design of platelet glycoprotein IIb/IIIa inhibition in coronary intervention.

Rarely is it straightforward to specify the design and parameters of a clinical trial investigating an alternative therapy where effective therapies already exist. If existing therapeutic interventions are highly efficacious, safe, inexpensive, and firmly entrenched, an active-control design becomes the logical first choice. Short of this absolute condition, however, the merits and realities of the scientific, clinical, corporate, and regulatory environments need to be weighed before determining the appropriate approach. A state of clinical equipoise with regard to the use of glycoprotein (GP) IIb/IIIa therapy in percutaneous coronary intervention (PCI) provided the unique opportunity to address the complexities in selecting a placebo-controlled design for the Enhanced Suppression of the Platelet IIb/IIIa Receptor with Integrilin Trial (ESPRIT). ESPRIT investigators assessed whether a high dose of eptifibatide would improve the outcomes of patients undergoing coronary stenting. By using the example of the ESPRIT trial, we examine factors warranting the need for this trial and evaluate the process whereby the United States Food and Drug Administration (FDA) gave approval for a placebo-controlled design. Although the focus of this trial is GP IIb/IIIa inhibition therapy, the issues pertaining to the trial and how they were resolved are general enough to be applied to the design and conduct of clinical trials across a broad spectrum of illnesses and therapeutic modalities.