Four year results: Abbott's MitraClip no better than surgery

Abbott Laboratories' MitraClip--Courtesy of Abbott Laboratories

After four years, patients with Abbott's ($ABT) MitraClip cardiac device required additional operations, and the benefits of the device were no better than those of traditional mitral valve surgery, a follow-up look at participants in the company's pivotal EVEREST II trial concludes.

The results could present a challenge to Abbott's approval prospects in the U.S., where Abbott is seeking the FDA's blessing to use MitraClip in patients for whom surgery is deemed too risky. Details of the four-year follow-up are published in the Journal of the American College of Cardiology.

As reports, lead study author Dr. Laura Mauri of Brigham and Women's Hospital in Boston was diplomatic, telling the publication that the trial "provides useful information about the long-term durability of the device," and that it showed MitraClip patients "have stable results" on par with surgery over at least the first three years after. MitraClip is designed to clip together parts of the mitral valve to help blood pump more efficiently, addressing a condition known as mitral regurgitation, which can lead to heart failure. It is delivered through the femoral vein in the leg, making it less invasive than straight surgery.

But the fact that the four-year data appears to favor regular mitral valve surgery could be ominous as Abbott awaits a decision from U.S. regulators. An FDA panel of experts voted that MitraClip's use for high-surgical-risk patents was beneficial, but they were mixed on its effectiveness compared to mitral valve surgery. FDA staff argued that in advance of the surgery it wasn't any safer than the surgical option and wanted to delay approval pending Abbott's collection of more trial data.

After four years, one out of every four patients treated with MitraClip needed additional surgery for mitral-valve problems, versus just 5.5% of patients who endured traditional mitral valve surgery. Also at four years: Patients with MitraClip experienced an effectiveness rate of just under 40%, versus 54% for patients who had surgery, a difference that was not statistically noteworthy, the article explains.

Abbott has argued that data from EVEREST II showed that MitraClip is safer than mitral valve surgery, reduces mortality rates and helped improve patients' quality of life. That has been truer after one year, at least in terms of safety, according to the story, but that advantage evens out later on.

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