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Clopidogrel Helps Patients With Established Heart Disease, Not "At-Risk" Individuals: Presented at ACC

By Ed Susman

ATLANTA, G.A. -- March 15, 2006 -- The platelet aggregation inhibitor clopidogrel (Plavix) failed to show superiority against aspirin alone in protecting people from developing coronary artery disease.

However, Deepak Bhatt, MD, associate director, Cardiovascular Coordinating Center, The Cleveland Clinic, Cleveland, Ohio, said that clopidogrel appeared to significantly help patients with symptoms avoid further complications of cardiovascular disease.

"These results are intriguing," said Dr. Bhatt, in presenting the results of the Clopidogrel for High Atherothrombotic Risk and Ischemic Stabilization, Management and Avoidance (CHARISMA) trial.

"They suggest that combination antiplatelet therapy might be useful in a large, new group of patients -- those with established cardiovascular disease," Dr. Bhatt said on March 12^th at the 55^th Annual Scientific Session of the American College of Cardiology (ACC). "However, the combination of aspirin and clopidogrel offers no benefit whatsoever in patients only having risk factor for developing vascular disease."

The CHARISMA team recruited 15,603 patients with either documented cardiovascular disease (previous heart attack, stroke, peripheral artery disease) or multiple risk factors for heart disease (diabetes, high blood pressure, high cholesterol).

After 28 months of follow-up, Dr. Bhatt analyzed the primary endpoint, which was a combination of adverse events - cardiovascular death, heat attack, or stroke. He found that the patients on dual aspirin-clopidogrel therapy had an event rate of 6.8% compared with 7.3% among those on aspirin. That relative risk reduction of 7.1% did not reach statistical significance (P =.22).

However, Dr. Bhatt noted that a secondary endpoint -- combination of the primary endpoint characteristics plus hospitalization for cardiovascular reasons -- was reduced by 7.7% in the combination group and that did reach statistical significance at the P =.04 level.

In looking at the 2 different groups of people in the trial -- those with symptoms and those who were asymptomatic but were at high risk -- it appeared that among those already suffering from cardiovascular disease there was a 12.5% relative risk reduction that did reach statistical significance at the P >.046 level. In that subgroup, 8.8% experienced 1 of the primary endpoints if they were on aspirin alone compared with 7.3% on aspirin plus clopidogrel.

On the other hand, if the dual platelet therapy was given just to patients with risk factors, there were actually excess events, Dr. Bhatt said. About 13.5% of people in this subgroup on aspirin-clopidogrel had events compared with 13.3% of patients on aspirin alone. That represents a relative risk reduction of -1.4%, meaning the treatment effect was in the wrong direction.

Steve Nissen, MD, director of cardiology, The Cleveland Clinic, who was not involved in the CHARISMA trial, commented that the main message of the study is that "clopidogrel is not for everyone."

Plavix is marketed by Sanofi-Aventis and Bristol-Myers Squibb.


[Presentation title: Clopidogrel for High Atherothrombotic Risk and Ischemic Stabilization, Management and Avoidance (CHARISMA). Late Breaker Presentation]

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