Medtronic has reported that its CoreValve System met the primary endpoint in a US pivotal trial in patients who were considered too ill or frail to undergo aortic valves replacement through traditional open-heart surgery.
According to the company, death or major stroke rate at one year was 25.5%, which was 40.7% lower than the standard therapy goal of 43%.
While the rate of strokes in the study involving 471 patients treated with the CoreValve System was 2.4% at one month and 4.1% at one year.
In addition, in more than 800 extreme risk patients enrolled in the CoreValve Continued Access Study, CoreValve patients experienced an even lower rate of major strokes (1.8% at one month).
The study results of the novel self-expanding device were presented at a late-breaking clinical trial session of the Transcatheter Cardiovascular Therapeutics (TCT) 2013 Conference.
Beth Israel Deaconess Medical Center, Boston director of interventional cardiology Dr Jeffrey J Popma, who was co-principal investigator of the trial presented the results at TCT, said the fact that nearly three-quarters of patients were alive and free of strokes at one year is remarkable, given the complex medical conditions and extreme frailty of the population.
"Not only do the results meet the CoreValve study's safety and efficacy endpoints for patients at extreme risk for surgery, but the positive clinical outcomes and low complication rates set a high standard for what transcatheter valves can achieve," Dr Popma said.
The study also found significant and sustained functional and quality-of-life improvements, with the heart failure symptoms of most patients (90.0%) improving at least one class at one year (as measured by NYHA Class), and quality-of-life scores improving 27.4 points at one year (as measured by the KCCQ 100-point scale, in which a 20-point change is considered highly significant).
Similar to gold standard surgical valves, the overall haemodynamic (blood flow) performance was strong with mean gradients (resistance) of 8.5mmHg at one month and 8.8mmHg at one year.
The trial results reported that only 11.5% of patients had more than mild paravalvular leak (PVL) at one month, which later improved to only 4.1% at one year.
Furthermore, CoreValve patients with moderate PVL had no greater mortality risk than patients with less PVL.
The trial also recorded low major vascular complication rates both at one month and one year.
Consistent with previous studies on self-expanding technology, the permanent pacemaker rate was 22.2% at one month and, importantly, pacemaker implants were not associated with mortality for these patients.
Medtronic senior vice-president Dr John Liddicoat said in the recent past, these patients had no good treatment option and a 50% chance of death at one year.
"Along with the clinical community, we are very encouraged by the results in this rigorously conducted trial and look forward to continuing our effort to bring this transformational therapy to patients with life-threatening aortic valve disease in the United States," Dr Liddicoat said.
"In particular, we wish to commend the 40 enrolling sites and their heart teams for their exceptional commitment to patients and for the meticulous conduct of this trial."
According to the company, all the patients were monitored by independent core labs and evaluated against a performance goal developed in partnership with the US Food and Drug Administration (FDA).
In the CoreValve Continued Access Study, 830 extreme risk patients have been treated with CoreValve System.
Following the review of the CoreValve trial results for extreme risk patients, the FDA determined that it has sufficient data to assess the safety and efficacy of the Medtronic CoreValve System for this patient group without the need for an external expert panel.
Medtronic anticipates obtaining the FDA approval by the end of its fiscal year 2014.
The CoreValve System, which received the CE mark approval in 2007 has been implanted in over 45,000 patients worldwide, excluding the US, where it is currently not approved for commercial use.
According to GlobalData estimates, the transcatheter heart valves market in the US was valued at $280m in 2012 and is expected to grow at a CAGR of 25.3% to reach $1.36bn by 2019.
Image: Medtronic world headquarters, Minneapolis, US. Photo: courtesy Medtronic, Inc.