An experimental, minimally invasive technique to repair the most common type of heart valve problem proved to be far safer and nearly as effective as open heart surgery, meeting the primary goals of a pivotal study, researchers said on Sunday.
Abbott Laboratories is hoping to use the data to win U.S. approval for the mitral valve repair device. Its MitraClip has been available in Europe for about 18 months.
In the first large trial of its kind, researchers compared the Abbott device — delivered to the heart via a catheter through a blood vessel in the leg — against open heart surgery to treat mitral regurgitation, or MR.
The primary safety goal of the study compared the number of major adverse events — a composite of 12, including major stroke, re-operation of mitral valve, urgent cardiovascular surgery, heart attack, kidney failure, major bleeding, and death — at 30 days.
Among patients who received the MitraClip, 9.6 percent suffered major adverse events compared with 57 percent in the surgery group, a difference considered to be highly statistically significant. In the surgery group, 42 of the 55 adverse events were major bleeding, researchers said.
Dr. Ted Feldman, director of the cardiac catheterization laboratory at NorthShore University HealthSystem in suburban Chicago and one of the studies lead investigators, called it one of the best safety results he had ever seen in a heart procedure.
There were no deaths, heart attacks, or major strokes among the clip patients in the study.
MR, which affects more than 8 million people in the United States and Europe, is marked by a faulty mitral valve that does not close tightly enough, allowing blood to flow backward in the heart.
It is a debilitating condition in which the heart's ability to function deteriorates over time, and can lead to serious heart problems and/or death.
Analysts believe the device could win U.S. approval next year and become a $1 billion a year product for Abbott.
Effectiveness was measured by the lack of need for surgery for valve dysfunction at one year. Moderate to severe MR in patients with initial successful treatment and death were also measures of efficacy at one year.
The device proved effective in 72.4 percent of patients compared with 87.8 percent in the surgery group, falling within pre-specified parameters of non-inferiority, researchers said.
"This is a stunning difference in safety for an acceptable trade-off in efficacy for many patients," said Feldman, who presented the data at the American College of Cardiology scientific meeting in Atlanta.
Under the trial's design, the MitraClip was meant to show superiority to surgery on safety but only non-inferiority on effectiveness.
"If a patient does not have success with the (device), he can still have surgery. The real take-home message from this is that this procedure gives patients another option," Feldman said, adding that the clip procedure could especially benefit elderly patients unable or unwilling to endure surgery.
At one year, patients with significant MR who received the MitraClip, demonstrated improvements in heart function, quality of life, and normal physical activity.
The repair device, which Abbott added to its portfolio with its acquisition of Evalve Inc. last year, works by clipping together the leaflets of the mitral valve, one of four valves in the heart.
The Abbott-sponsored trial, dubbed EVEREST II, randomized 279 patients with moderate-to-severe or severe MR into two groups with 184 receiving the MitraClip and 95 undergoing surgery, the current standard of care.
Patients who received the device also demonstrated a reduction in severity of MR, an improvement in heart function and symptoms, as well as an improvement in physical and mental quality of life.
The average hospital stay for a surgery patient is about three times that for the device procedure and recovery times are much shorter, Feldman said.
John Capek, executive vice president of medical devices for Abbott, said he believed these results would accelerate adoption of the technology in Europe, where the company plans to add marketing resources.
If approved in the United States, Abbott would have exclusivity in the market for a couple of years at least, he told Reuters in a telephone interview.
Revenue contribution from MitraClip, he said, would be "several hundred million" dollars over the next three to five years, a forecast he characterized as "conservative."
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