Abbott announced data from its EVEREST II (Endovascular valve edge-to-edge repair study) study showing that patients with significant mitral regurgitation treated with its investigational percutaneous catheter-based MitraClip system continue to demonstrate the clinical benefits of initial treatment shown at one year, out to two years, including improvements in heart function and reductions in symptoms.
EVEREST II is the first randomised clinical trial, in the United States and Canada, to compare a catheter-based mitral valve device to mitral valve surgery. Data from the study were published in The New England Journal of Medicine and presented in a late-breaking clinical trial session at the American College of Cardiology’s (ACC) 60th Annual Scientific Session and i2 Summit 2011 in New Orleans.
At two years after treatment, data from 279 patients from the EVERESTII 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=0.04) on an Intention-to-treat basis. These results compare with the one-year data, which demonstrated a clinical success rate of 55.2% for patients who received the MitraClip device, compared to a clinical success rate of 73.0% for surgery patients (p=0.0007). The clinical success rate is defined as freedom from death, from surgery for valve dysfunction, and from moderate to severe mitral regurgitation (3+ or 4+).
In The New England Journal of Medicine, the study authors state 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 New York Heart Association class and quality of life.”
“These results reinforce that the MitraClip device continues to be effective out to two years, confirming the durability of the clinical benefit and the safety profile of the therapy. Surgery also performed well in the trial,” said Ted Feldman, director, Cardiac Catheterization Laboratory, and The Mr and Mrs Charles R Walgreen Chair in Interventional Cardiology, NorthShore University HealthSystem, Evanston, Ill. “The MitraClip system offers an option that addresses the unmet need for a percutaneous approach to treating mitral regurgitation, which may be especially important for many patients who are considered high-risk surgical candidates.”
Feldman served as co-principal investigator of the EVEREST II trial, was the lead author of the New England Journal of Medicine publication, and presented the two-year EVEREST II data during the late-breaking clinical trial session at ACC.
“In the EVEREST II study, the MitraClip device demonstrated strong safety and meaningful clinical benefits,” said Donald Glower, professor of surgery, Cardiovascular and Thoracic Surgery Division, Duke University School of Medicine, Durham, USA, co-principal investigator of the EVEREST II trial and an author of the New England Journal of Medicine publication. “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 mitral regurgitation.”
Charles A Simonton, divisional vice president, Medical Affairs, and chief medical officer, Abbott Vascular, commented “Nearly 3,000 patients around the world have now been treated with the MitraClip device. We look forward to an FDA Advisory Panel to review the safety and effectiveness of the MitraClip device this year, hopefully bringing the technology a step closer to being available to US physicians and patients.”
Additional EVEREST II two years’ data
In addition to the clinical success rate at one and two years, data from the EVEREST II study showed the following on an intention-to-treat basis:
- At 30 days, the MitraClip system demonstrated superior safety compared to surgery, with 15.0% of MitraClip patients and 47.9% of surgery patients experiencing a major adverse event (MAE) (p<0.001) Major adverse events are defined as a composite of 12 pre-specified adverse events.
- At one and two years, both the MitraClip and surgery groups experienced a significant reduction (p<0.05) in the end systolic and diastolic volume of the left ventricule 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 one year continued to decrease between years one and two.
- Both the MitraClip device and surgery experienced a statistically significant reduction in New York Heart Association (NYHA) Functional Class symptoms at one year that was sustained through two years. NYHA Functional Class provides a scale that assists in the determination of functional ability in patients with heart disease.
- At two years, 78% of patients randomised to the MitraClip device were free from surgery.
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.