Two-Year EVEREST II Data Show Durable Clinical Benefits of Abbott's MitraClip System

April 4, 2011—Abbott Vascular (Santa Clara, CA) announced data from its EVEREST II (Endovascular Valve Edge-to-Edge Repair Study) study showing that patients with significant mitral regurgitation (MR) treated with the company's investigational percutaneous catheter–based MitraClip system continue to demonstrate the clinical benefits of initial treatment shown at 1 year out to 2 years, including improvements in heart function and reductions in symptoms.

Coprincipal investigator Ted Feldman, MD, presented the data at the American College of Cardiology's 60th annual scientific session in New Orleans. The EVEREST II investigators simultaneously published the data online ahead of print in The New England Journal of Medicine (2011;364:1395–1406). The EVEREST II investigators represent a variety of specialties including cardiac surgery and interventional cardiology, the company noted.

According to Abbott Vascular, the 2-year data from 279 patients from the EVEREST II trial demonstrated a clinical success rate of 51.7% for patients treated with the MitraClip device compared to a clinical success rate of 66.3% for surgery patients (P = .04) on an intention-to-treat basis. These results compare with the 1-year data, which demonstrated a clinical success rate of 55.2% for patients who received the MitraClip device and 73% for surgery patients (P = .0007). The clinical success rate is defined as freedom from death, surgery for valve dysfunction, and moderate to severe MR (3+ or 4+).

Data from the EVEREST II study showed other positive benefits on an intention-to-treat basis.

At 30 days, the MitraClip system demonstrated superior safety compared to surgery, with 15% of MitraClip patients and 47.9% of surgery patients experiencing a major adverse event, defined as a composite of 12 pre-specified adverse events (P < .001).

At 1 and 2 years, both the MitraClip and surgery groups experienced a significant reduction (P < .05) in the end systolic and end diastolic volume of the left ventricle heart chamber compared to baseline, indicating an improvement in heart function. In both groups, the decrease in end diastolic volume that was observed between baseline and 1 year continued to decrease between years 1 and 2.

Both the MitraClip device and surgery experienced a statistically significant reduction in New York Heart Association (NYHA) Functional Class symptoms at 1 year that was sustained through 2 years.

At 2 years, 78% of patients randomized to the MitraClip device were free from surgery.

Abbott Vascular stated that longer-term follow-up of patients in EVEREST II is planned and will provide additional data to better understand the benefits of the MitraClip device. The company also noted that 2-year results from patients with functional MR and patients considered at high risk for mitral valve surgery were also featured in presentations at ACC. Results from both presentations demonstrated that positive 1-year clinical outcomes were sustained out to 2 years.

In The New England Journal of Medicine, the EVEREST II investigators stated that “although percutaneous repair was less effective at reducing mitral regurgitation than surgery before hospital discharge, at 12 and 24 months the rates of reduction in mitral regurgitation were similar, and percutaneous treatment was associated with increased safety, improved left ventricular dimensions, and clinical improvements in NYHA class and quality of life."

Dr. Feldman commented, "These results reinforce that the MitraClip device continues to be effective out to 2 years, confirming the durability of the clinical benefit and the safety profile of the therapy. Surgery also performed well in the trial. The MitraClip system offers an option that addresses the unmet need for a percutaneous approach to treating MR, which may be especially important for many patients who are considered high-risk surgical candidates."

"In the EVEREST II study, the MitraClip device demonstrated strong safety and meaningful clinical benefits," observed coprincipal investigator Donald Glower, MD. "The MitraClip system's positive risk-benefit profile supports its use as a treatment choice for patients who are not good candidates for surgery and have few other options, including elderly or frail patients, those who are at high risk for surgery, and certain patients with functional MR."

The MitraClip system received CE Mark in March 2008 and is commercially available in Europe, Turkey, Israel, and Australia. The first-in-man clinical trial of the MitraClip system was conducted in the United States, where it is an investigational device currently under review for approval by the US Food and Drug Administration, advised Abbott Vascular.