March 20 A clinical trial evaluating St. Jude Medical Inc's implantable device used to prevent stroke in patients who have a common congenital heart defect failed to achieve its main goal.
St. Jude, which paid for the 980-patient study, said it used the trial data to file for U.S. regulatory approval and submitted an application to the U.S. Food and Drug Administration in the fourth quarter of 2012.
The device, a permanent implant, is used on people who have a hole in the wall that separates the left and right upper chambers, of the heart. Everyone has a hole present at birth, but it never closes in about one-quarter of the population, according to the National Institutes of Health.
The hole - called a patent foramen ovale, or PFO as it is more commonly known - raises the risk of stroke. It usually is not treated unless a blood clot causes a stroke, or if there are other heart problems. When relatively young people have a stroke without an identifiable cause, a PFO is often suspected.
Dr. Jeffrey Saver, director of the UCLA Stroke Center and one of the lead investigators of the study, dubbed RESPECT, said the trial demonstrated that implanting the device in the heart is likely a better strategy for reducing stroke than just using anti-clotting medication, such as aspirin or Warfarin.
"It's not formally a positive trial; it missed the primary endpoint," Saver said in a telephone interview.
Results of the trial were published in the New England Journal of Medicine.
The study showed a 51 percent reduction in stroke in the group of patients who got the device versus those who were treated with drugs.
The goal of the study had been to detect a 75 percent reduction in stroke, he said.
"That was an over optimistic goal to reach for," he added.
There is still evidence of superiority, and so some doctors might use the PFO closure device because it allows patients to rely less on anti-clotting drugs, which carry a risk of bleeding.
Saver said doctors estimate that medication alone cuts the risk of stroke by 20 percent to 60 percent in patients who have PFO. The risk is only an estimate because it never has been studied for ethical reasons.
In a prepared statement, St. Jude said the Respect study provides "compelling evidence" that its device, called AMPLATZER PFO Occluder, is superior to drugs.
"The totality of evidence from this study, including the strong performance and safety profile of the device, demonstrates the compelling clinical benefits of closure versus medical management in reducing the likelihood of recurrent stroke in this patient population," Frank Callaghan, president of the St. Jude Medical Cardiovascular and Ablation Technologies Division, said in an emailed statement.
The device won European regulatory approval in 1998. It is available in more than 60 countries outside the United States, including Canada, Latin America, Europe, Australia, Asia and the Middle East.