Newer Blood Thinner Beats Plavix for Bypass Patients
TUESDAY, March 16 -- In a trial comparing two anti-clotting drugs, patients given Brilinta before cardiac bypass surgery were less likely to die than those given Plavix, researchers found.
Both drugs prevent platelets from clumping and forming clots, but Plavix, the more popular drug, has been linked to potentially dangerous side effects in cancer patients. In addition, some people don't metabolize it well, making it less effective.
"We did see about a 50 percent reduction in mortality in these patients [who took Brilinta], but without any increase in bleeding complications," Dr. Claes Held, an associate professor of cardiology at the Uppsala Clinical Research Center at Uppsala University in Sweden and the study's lead researcher, said during an afternoon press conference Tuesday.
"Ticagrelor (Brilinta) in this setting, with acute coronary syndrome patients with the potential need for bypass surgery, is more effective than clopidogrel (Plavix) in preventing cardiovascular and total mortality without increasing the risk of bleeding," he said.
A danger with any anti-platelet drug is the risk of uncontrolled bleeding, which is why these drugs are stopped before patients undergo surgery.
Held was scheduled to present the results Tuesday at the American College of Cardiology's annual meeting in Atlanta.
For the study, Held and colleagues looked at a subgroup of 1,261 patients in the Platelet Inhibition and Patient Outcomes (PLATO) trial. The researchers found that 10.5 percent of the patients given Brilinta plus aspirin before surgery had a heart attack, stroke or died from heart disease within a week after surgery. Among patients given Plavix plus aspirin, 12.6 percent had the same adverse outcomes.
Patients taking Brilinta had a total death rate of 4.6 percent, compared with 9.2 percent for patients taking Plavix. In addition, the cardiovascular death rates were 4 percent among patients taking Brilinta and 7.5 percent among those taking Plavix.
When Held's team looked at each group individually, they found no statistically significant difference for heart attack and stroke and no significant difference in major bleeding from the bypass operation itself.
The two drugs work in different ways.
Plavix needs the body to convert it to an active form, which poses some problems. Last week, the U.S. Food and Drug Administration required Bristol-Myers Squibb and Sanofi Aventis, the makers of Plavix, to add a "black box" warning to the drug's label, alerting doctors and patients that some patients cannot fully convert the drug, so it may be less effective for them.
Brilinta, which is in a different class of drugs, does not rely on metabolic conversion, so it acts faster and clears the body faster than Plavix. This enables quicker recovery of normal platelet function, the researchers say.
But Held can't explain the difference in the rate of death. "That's the billion dollar question," he said.
"Right now we don't understand the mechanism. We see the difference in mortality, but we cannot explain it in differences in bleeding so there has to be some other effect explaining the difference," Held said.
The PLATO study was funded by AstraZeneca, the maker of Brilinta.
Results of another study presented at the meeting Tuesday found that the drug Tekturna (aliskiren) given to patients after a heart attack did not improve heart function as researchers had hoped. In that trial -- called the Aliskiren Study in Post-MI Patients to Reduce Remodeling (ASPIRE) -- Tekturna, which blocks the hormone renin, was given to patients along with common blood pressure-lowering drugs. But the researchers found it provided no additional benefit in heart function and only served to raise potassium levels and cause low blood pressure.
"Morbidity and mortality remain high in patients following heart attack, with a substantial number of patients subsequently developing heart failure," Dr. Scott D. Solomon, director of noninvasive cardiology at the Brigham and Women's Hospital, Harvard Medical School in Boston and lead researcher, said in a statement.
"We hoped that this study would generate the information needed to plan a major morbidity and mortality trial. However, our results show that the addition of aliskiren to standard therapy in high-risk post-MI patients does not affect left ventricular size or function. These findings suggest the need for caution when treating post-heart attack patients," he added.
For more information on anti-platelet drugs, visit the American Heart Association.
Posted: March 2010