Super Aspirins for Heart Attack Patients Getting Mixed Reviews
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Robert M. Califf, MD, professor of medicine and director of the Duke Clinical Research Institute in Durham, N.C., says that these latest results were very much a replay of earlier clinical trials, which demonstrated again and again that oral super aspirin is no match for regular aspirin. Overall, patients taking sibrafiban at any dose were more likely to have an adverse event and were more likely to have a major bleeding event, he says.
The most damaging finding in the trials of oral super aspirin concerned mortality. In both trials, very few patients died, but in each study, more deaths occurred among patients treated with the super aspirin than with plain aspirin.
Moreover, Califf says that it is still unclear why the oral drugs cause this excess mortality. "Almost certainly it is not due to bleeding. Most of these deaths were sudden ... deaths," he says. Super aspirin theoretically works by thinning the blood -- making it less likely to clot. According to Califf, it's possible that the oral drugs may work opposite from the IV formulation -- making the person more likely to develop life-threatening clots in the heart or brain.
Eugene Braunwald, MD, professor of medicine at Harvard University School of Medicine, says that he, too, thinks this may be the problem. He tells WebMD that scientists might need to develop a newer super aspirin that won't promote blood clots.
Despite the recent spate of negative results from the oral super aspirin trials, scientists plan to continue human study of the agents. Currently, there are two trials underway. One study has enrolled 6,000 patients so far, says Califf, who adds that, in light of the negative findings from the recent oral super aspirin trials, the scientists will be closely monitoring those trials for adverse events and "will act immediately if it turns out that early results are not good."
Braunwald says that the current trials with the oral agents remind him of earlier disappointments in cardiology that only turned into success once further clinical trials took place. For example, the first trials of heart bypass surgery were negative, he says. Likewise, once cardiologists determined that controlling blood pressure "would be good," he says, "we had several disappointing trials of bad hypertension drugs. ... It took awhile for them to get it right."