Experts Support FDA Panel's Backing of New Blood Thinner
THURSDAY, July 29 (HealthDay News) -- Following a federal health panel's endorsement of the new blood thinner Brilinta Wednesday, cardiologists say the drug could be a welcome addition to treatments for heart patients.
In a 7-to-1 vote, the U.S. Food and Drug Administration's Cardiovascular and Renal Drugs Advisory Committee recommended approval of the drug for heart patients undergoing angioplasty or stenting to open blocked arteries, and for those not requiring such interventions but being managed with drug therapy alone.
The panel's nod was partly based on the results of a clinical trial, called PLATO, that pitted ticagrelor (Brilinta) against the current standard anticoagulant, clopidogrel (Plavix).
In that trial, Brilinta was found to be more effective than Plavix, with similar risks, for patients with acute coronary syndrome. The syndrome covers a variety of symptoms, from chest pain to heart attack.
While the FDA does not have to abide by the committee's recommendations, it usually does. According to the Dow Jones news service, the agency is expected to make a final decision on the drug by Sept. 16.
"Brilinta is an oral, direct-acting and reversible inhibitor of receptors on platelets," blood cells that aid in clotting, explained Dr. Gregg C. Fonarow, director of the Ahmanson-UCLA Cardiomyopathy Center at the University of California, Los Angeles. Like Plavix, Brilinta works by keeping platelets from sticking together and forming potentially dangerous clots.
"It has a more rapid onset and more pronounced effect at inhibiting platelets than Plavix," Fonarow added.
Another expert said an advantage of Brilinta over Plavix is its ability to be metabolized by all patients.
"One problem with Plavix is some small percentage of the population are what's called slow metabolizers on a genetic basis," Robert J. Myerburg, a professor of medicine and physiology in the Cardiovascular Division at the University of Miami Miller School of Medicine. "Their gene makeup is such that they don't metabolize Plavix as the majority of the population [does]."
With Plavix, the drug has to be metabolized for it to be effective, he said. Since Brilinta does not appear to have this problem, it has another advantage over Plavix, Myerburg said. So it should be effective in all patients.
The international PLATO trial, funded by Brilinta's maker, AstraZeneca, showed that in patients with a heart attack, treatment with the drug reduced the rate of death, heart attack or stroke compared to treatment with Plavix. The benefit was seen without any increased risk in major bleeding, a prime worry with blood thinners, Fonarow said.
The trial results were not without controversy, however. That's because when investigators focused only on patients in PLATO who were from the United States, Brilinta actually performed worse compared to those who got Plavix -- contrary to results for patients treated elsewhere. According to Dow Jones, the FDA advisory panel wrestled with that discrepancy, suggesting that differences in levels of care, or the "generally higher" dose of aspirin that American patients received may have been to blame.
And Fonarow mentioned another potential drawback with Brilinta. "While this [drug] has a number of attractive features and results in improved outcomes compared to standard-dose clopidogrel, it does need to be taken twice daily," Fonarow noted. Both Plavix and another anticoagulant, Effiant, need to be taken only once a day, he said.
However, if Brilinta gains FDA approval, it is likely that all three of these antiplatelet medications will have an important role in the management of acute coronary syndrome patients, "with the choice among these agents depending on a number of patient, physician and system factors," he added.
Another expert, Dr. Jeffrey S. Borer, director of cardiovascular medicine at the State University of New York Downstate Medical Center, believes that "this new drug is better than the old drug [Plavix]."
Although Brilinta performed well in a supervised clinical trial, how it will perform when made available to thousands of patients remains unknown, Borer said. "If you put the drug out into general use, we don't really know for sure that the safety results will be exactly the same in general use as they were in a monitored trial," he said.
While the safety of Brilinta is the same as Plavix for major bleeding, there are some side effects associated with Brilinta that were not seen with Plavix, Borer said.
These include difficulty breathing and a heart rhythm problem called heart block. Both these conditions occurred in few patients and can be treated, the expert said.
"On balance, Brilinta is sufficiently safe for its intended use and has greater efficacy than the drug that is the standard for use," Borer said.
"Brilinta offers great promise without increase in important safety risks and that's why the drug is probably going to be a very useful addition to the armamentarium of doctors taking care of patients with acute coronary syndrome and related problems," he said.
In a statement, AstraZeneca's chief medical officer Dr. Howard Hutchinson, said the company is "pleased with the Advisory Committee's recommendation to support the approval of ticagrelor. We look forward to continued discussions with the FDA as it evaluates the panel's recommendation and completes its review of the new drug application."
For more information on blood thinners, visit the U.S. National Library of Medicine.