CLINICAL STUDIES

The clinical evidence for the efficacy of PLAVIX is derived from four double-blind trials involving 81,090 patients: the CAPRIE study (Clopidogrel vs. Aspirin in Patients at Risk of Ischemic Events), a comparison of PLAVIX to aspirin, and the CURE (Clopidogrel in Unstable Angina to Prevent Recurrent Ischemic Events), the COMMIT/CCS-2 (Clopidogrel and Metoprolol in Myocardial Infarction Trial / Second Chinese Cardiac Study) studies comparing PLAVIX to placebo, both given in combination with aspirin and other standard therapy and CLARITY-TIMI 28 (Clopidogrel as Adjunctive Reperfusion Therapy – Thrombolysis in Myocardial Infarction). Recent Myocardial Infarction (MI), Recent Stroke or Established Peripheral Arterial Disease The CAPRIE trial was a 19,185-patient, 304-center, international, randomized, double-blind, parallel-group study comparing PLAVIX (75 mg daily) to aspirin (325 mg daily). The patients randomized had: 1) recent histories of myocardial infarction (within 35 days); 2) recent histories of ischemic stroke (within 6 months) with at least a week of residual neurological signs; or 3) objectively established peripheral arterial disease. Patients received randomized treatment for an average of 1.6 years (maximum of 3 years). The trial’s primary outcome was the time to first occurrence of new ischemic stroke (fatal or not), new myocardial infarction (fatal or not), or other vascular death. Deaths not easily attributable to nonvascular causes were all classified as vascular. Table 2: Outcome Events in the CAPRIE Primary Analysis Patients PLAVIX 9599 aspirin 9586 IS (fatal or not) 438 (4.6%) 461 (4.8%) MI (fatal or not) 275 (2.9%) 333 (3.5%) Other vascular death 226 (2.4%) 226 (2.4%) Total 939 (9.8%) 1020 (10.6%) As shown in the table, PLAVIX (clopidogrel bisulfate) was associated with a lower incidence of outcome events of every kind. The overall risk reduction (9.8% vs. 10.6%) was 8.7%, P=0.045. Similar results were obtained when all-cause mortality and all-cause strokes were counted instead of vascular mortality and ischemic strokes (risk reduction 6.9%). In patients who survived an on-study stroke or myocardial infarction, the incidence of subsequent events was again lower in the PLAVIX group. The curves showing the overall event rate are shown in Figure 1. The event curves separated early and continued to diverge over the 3-year follow-up period. Figure 1: Fatal or Non-Fatal Vascular Events in the CAPRIE Study Although the statistical significance favoring PLAVIX over aspirin was marginal (P=0.045), and represents the result of a single trial that has not been replicated, the comparator drug, aspirin, is itself effective (vs. placebo) in reducing cardiovascular events in patients with recent myocardial infarction or stroke. Thus, the difference between PLAVIX and placebo, although not measured directly, is substantial. The CAPRIE trial included a population that was randomized on the basis of 3 entry criteria. The efficacy of PLAVIX relative to aspirin was heterogeneous across these randomized subgroups (P=0.043). It is not clear whether this difference is real or a chance occurrence. Although the CAPRIE trial was not designed to evaluate the relative benefit of PLAVIX over aspirin in the individual patient subgroups, the benefit appeared to be strongest in patients who were enrolled because of peripheral vascular disease (especially those who also had a history of myocardial infarction) and weaker in stroke patients. In patients who were enrolled in the trial on the sole basis of a recent myocardial infarction, PLAVIX was not numerically superior to aspirin. In the meta-analyses of studies of aspirin vs. placebo in patients similar to those in CAPRIE, aspirin was associated with a reduced incidence of thrombotic events. There was a suggestion of heterogeneity in these studies too, with the effect strongest in patients with a history of myocardial infarction, weaker in patients with a history of stroke, and not discernible in patients with a history of peripheral vascular disease. With respect to the inferred comparison of PLAVIX to placebo, there is no indication of heterogeneity. Figure Acute Coronary Syndrome The CURE study included 12,562 patients with acute coronary syndrome without ST segment elevation (unstable angina or non-Q-wave myocardial infarction) and presenting within 24 hours of onset of the most recent episode of chest pain or symptoms consistent with ischemia. Patients were required to have either ECG changes compatible with new ischemia (without ST segment elevation) or elevated cardiac enzymes or troponin I or T to at least twice the upper limit of normal. The patient population was largely Caucasian (82%) and included 38% women, and 52% patients ≥65 years of age. Patients were randomized to receive PLAVIX (300 mg loading dose followed by 75 mg/day) or placebo, and were treated for up to one year. Patients also received aspirin (75–325 mg once daily) and other standard therapies such as heparin. The use of GPIIb/IIIa inhibitors was not permitted for three days prior to randomization. The number of patients experiencing the primary outcome (CV death, MI, or stroke) was 582 (9.30%) in the PLAVIX-treated group and 719 (11.41%) in the placebo-treated group, a 20% relative risk reduction (95% CI of 10%–28%; p=0.00009) for the PLAVIX-treated group (see Table 3). At the end of 12 months, the number of patients experiencing the co-primary outcome (CV death, MI, stroke or refractory ischemia) was 1035 (16.54%) in the PLAVIX-treated group and 1187 (18.83%) in the placebo-treated group, a 14% relative risk reduction (95% CI of 6%–21%, p=0.0005) for the PLAVIX-treated group (see Table 3). In the PLAVIX-treated group, each component of the two primary endpoints (CV death, MI, stroke, refractory ischemia) occurred less frequently than in the placebo-treated group. Table 3: Outcome Events in the CURE Primary Analysis Outcome PLAVIX (+ aspirin)Other standard therapies were used as appropriate. Placebo (+ aspirin) Relative Risk Reduction (%) (95% CI) (n=6259) (n=6303) Primary outcome 582 (9.3%) 719 (11.4%) 20% (Cardiovascular death, MI, Stroke) (10.3, 27.9) P=0.00009 Co-primary outcome 1035 (16.5%) 1187 (18.8%) 14% (Cardiovascular death, MI, Stroke, Refractory Ischemia) (6.2, 20.6) P=0.00052 All Individual Outcome Events: CV death 318 (5.1%) 345 (5.5%) 7% (-7.7, 20.6) MI 324 (5.2%) 419 (6.6%) 23% (11.0, 33.4) Stroke 75 (1.2%) 87 (1.4%) 14% (-17.7, 36.6) Refractory ischemia 544 (8.7%) 587 (9.3%) 7% (-4.0, 18.0) The benefits of PLAVIX (clopidogrel bisulfate) were maintained throughout the course of the trial (up to 12 months). Figure 2: Cardiovascular Death, Myocardial Infarction, and Stroke in the CURE Study In CURE, the use of PLAVIX was associated with a lower incidence of CV death, MI or stroke in patient populations with different characteristics, as shown in Figure 3. The benefits associated with PLAVIX were independent of the use of other acute and long-term cardiovascular therapies, including heparin/LMWH (low molecular weight heparin), IV glycoprotein IIb/IIIa (GPIIb/IIIa) inhibitors, lipid-lowering drugs, beta-blockers, and ACE-inhibitors. The efficacy of PLAVIX was observed independently of the dose of aspirin (75–325 mg once daily). The use of oral anticoagulants, non-study anti-platelet drugs and chronic NSAIDs was not allowed in CURE. Figure 3: Hazard Ratio for Patient Baseline Characteristics and On-Study Concomitant Medications/Interventions for the CURE Study The use of PLAVIX in CURE was associated with a decrease in the use of thrombolytic therapy (71 patients [1.1%] in the PLAVIX group, 126 patients [2.0%] in the placebo group; relative risk reduction of 43%, P=0.0001), and GPIIb/IIIa inhibitors (369 patients [5.9%] in the PLAVIX group, 454 patients [7.2%] in the placebo group, relative risk reduction of 18%, P=0.003). The use of PLAVIX in CURE did not impact the number of patients treated with CABG or PCI (with or without stenting), (2253 patients [36.0%] in the PLAVIX group, 2324 patients [36.9%] in the placebo group; relative risk reduction of 4.0%, P=0.1658). In patients with ST-segment elevation acute myocardial infarction, safety and efficacy of clopidogrel have been evaluated in two randomized, placebo-controlled, double-blind studies, COMMIT- a large outcome study conducted in China – and CLARITY- a supportive study of a surrogate endpoint conducted internationally. The randomized, double-blind, placebo-controlled, 2×2 factorial design COMMIT trial included 45,852 patients presenting within 24 hours of the onset of the symptoms of suspected myocardial infarction with supporting ECG abnormalities (i.e., ST elevation, ST depression or left bundle-branch block). Patients were randomized to receive PLAVIX (75 mg/day) or placebo, in combination with aspirin (162 mg/day), for 28 days or until hospital discharge whichever came first. The co-primary endpoints were death from any cause and the first occurrence of re-infarction, stroke or death. The patient population included 28% women, 58% patients ≥60 years (26% patients ≥70 years) and 55% patients who received thrombolytics, 68% received ace-inhibitors, and only 3% had percutaneous coronary intervention (PCI). As shown in Table 4 and Figures 4 and 5 below, PLAVIX significantly reduced the relative risk of death from any cause by 7% (p = 0.029), and the relative risk of the combination of re-infarction, stroke or death by 9% (p = 0.002). Table 4: Outcome Events in the COMMIT Analysis Event PLAVIX (+ aspirin) (N=22961) Placebo (+ aspirin) (N=22891) Odds ratio (95% CI) p-value Composite endpoint: Death, MI, or Stroke 2121 (9.2%) 2310 (10.1%) 0.91 (0.86, 0.97) 0.002 Death 1726 (7.5%) 1845 (8.1%) 0.93 (0.87, 0.99) 0.029 Non-fatal MINon-fatal MI and non-fatal stroke exclude patients who died (of any cause). 270 (1.2%) 330 (1.4%) 0.81 (0.69, 0.95) 0.011 Non-fatal Stroke 127 (0.6%) 142 (0.6%) 0.89 (0.70, 1.13) 0.33 Figure 4: Cumulative Event Rates for Death in the COMMIT Study Figure 5: Cumulative Event Rates for the Combined Endpoint Re-Infarction, Stroke or Death in the COMMIT Study The effect of PLAVIX did not differ significantly in various pre-specified subgroups as shown in Figure 6. Additionally, the effect was similar in non-prespecified subgroups including those based on infarct location, Killip class or prior MI history (see Figure 7). Such subgroup analyses should be interpreted very cautiously. Figure 6: Effects of Adding PLAVIX to Aspirin on the Combined Primary Endpoint across Baseline and Concomitant Medication Subgroups for the COMMIT Study Figure 7: Effects of Adding PLAVIX to Aspirin in the Non-Prespecified Subgroups in the COMMIT Study The randomized, double-blind, placebo-controlled CLARITY trial included 3,491 patients, 5% U.S., presenting within 12 hours of the onset of a ST elevation myocardial infarction and planned for thrombolytic therapy. Patients were randomized to receive PLAVIX (300-mg loading dose, followed by 75 mg/day) or placebo until angiography, discharge, or Day 8. Patients also received aspirin (150 to 325 mg as a loading dose, followed by 75 to 162 mg/day), a fibrinolytic agent and, when appropriate, heparin for 48 hours. The patients were followed for 30 days. The primary endpoint was the occurrence of the composite of an occluded infarct-related artery (defined as TIMI Flow Grade 0 or 1) on the predischarge angiogram, or death or recurrent myocardial infarction by the time of the start of coronary angiography. The patient population was mostly Caucasian (89.5%) and included 19.7% women and 29.2% patients ≥65 years. A total of 99.7% of patients received fibrinolytics (fibrin specific: 68.7%, non-fibrin specific: 31.1%), 89.5% heparin, 78.7% beta-blockers, 54.7% ACE inhibitors and 63% statins. The number of patients who reached the primary endpoint was 262 (15.0%) in the PLAVIX-treated group and 377 (21.7%) in the placebo group, but most of the events related to the surrogate endpoint of vessel patency. Table 5: Event Rates for the Primary Composite Endpoint in the CLARITY Study Clopidogrel 1752 Placebo 1739 OR 95% CI *The total number of patients with a component event (occluded IRA, death, or recurrent MI) is greater than the number of patients with a composite event because some patients had more than a single type of component event. Number (%) of patients reporting the composite endpoint 262 (15.0%) 377 (21.7%) 0.64 0.53, 0.76 Occluded IRA N (subjects undergoing angiography) 1640 1634 n (%) patients reporting endpoint 192 (11.7%) 301 (18.4%) 0.59 0.48, 0.72 Death n (%) patients reporting endpoint 45 (2.6%) 38 (2.2%) 1.18 0.76, 1.83 Recurrent MI n (%) patients reporting endpoint 44 (2.5%) 62 (3.6%) 0.69 0.47, 1.02 Figure Figure Figure Figure Figure Figure