AUSTIN, Texas -- On-X® Life Technologies, Inc. (On-X LTI) announced today that preliminary results from a Food and Drug Administration (FDA) Investigational Device Exemption (IDE) study of the On-X® Prosthetic Heart Valve continue to show promise for patients who want relief from taking life-long anticoagulants while minimizing the risk of bleeding. Preliminary results of the PROACT study show that the On-X® valve continues to demonstrate tolerance of low International Normalized Ratios (INR) in high-risk aortic patients as seen previously in worldwide studies. The Lead Investigator of the PROACT study, John D. Puskas, M.D., Emory University, Atlanta, presented the findings at the American College of Cardiology on April 5, 2011.
The preliminary report of PROACT trial data for the high-risk aortic patient test and control groups shows that, as hypothesized, patients in the test group with INRs between 1.5 and 2.0 are currently equal in composite thromboembolism and hemorrhage rates compared to the control group of patients. High-risk aortic patients are those who have a higher potential for thrombotic or bleeding events. All patients received an On-X valve as a replacement for their aortic valve. These were randomized into Test and Control groups for the trial. Both patient groups were maintained with standard anticoagulation therapy for the first three months after surgery and then randomized into the Test and Control groups. The Test group was maintained with a daily dose of either 81 or 325 milligrams of baby aspirin plus warfarin to achieve an INR target of 1.5 to 2.0. The Control group continued with standard anticoagulation therapy throughout the trial.
Other study limbs include:
- a lower-risk aortic valve patient group that is maintained with aspirin and clopidogrel (brand name PLAVIX®)—without warfarin; and
- a mitral valve group that is maintained at an INR level of 2.0 to 2.5 INR with warfarin.
“Our goal is to maintain patients with this type of mechanical valve (On-X) on a safer and more convenient regimen that’s closer to the benefits of biological valves,” said Puskas. “The data so far are encouraging and the other study limbs are likely to show similar findings. If final data confirm these early results, the FDA may grant a label for lower doses of anticoagulation drugs. One day, we may be able to offer a durable mechanical heart valve with no blood thinner to selected patients.”
The Prospective Randomized On-X Valve Anticoagulation Trial (PROACT) was initiated in 2006 and is currently ongoing in 40 centers throughout the United States and Canada because of the exceptional clinical outcomes seen in clinical trials since the On-X valve was introduced in 1996. The purpose of the PROACT trial is to determine if patients implanted with the On-X valve can be safely maintained with reduced levels of warfarin (brand name Coumadin®) anticoagulation or eliminated use of warfarin altogether.
“The preliminary results of the PROACT trial in higher-risk aortic valve patients suggest that the On-X valve may require lesser levels of anticoagulation, which would lower the risk of hemorrhage without increasing the risk of thromboemboli or thrombosis,” said Allen Henry Graeve, M.D., Medical Director, Cardiothoracic Surgery, Tacoma General Hospital, Tacoma, Washington. “If the preliminary results are confirmed, younger patients would be better served choosing the On-X valve over a tissue valve, for its performance, longevity and overall safety. Older patients, even age 70 or above with a 12-15 year life expectancy, would be similarly well served.”
The On-X valve is the result of a breakthrough in medical grade carbon technology—On-X® pure pyrolytic carbon. In addition to providing a more thromboresistant surface, the comparatively high strength of pure On-X Carbon® enabled On-X LTI to make significant valve design changes that resulted in a prosthesis that acts more like a natural valve in its treatment of blood. It is well documented that the On-X valve does not produce the turbulence and blood damage commonly produced by other mechanical heart valve prostheses and, therefore, significantly reduces the potential for life-threatening blood clots.
“We are very pleased with how the preliminary report is demonstrating the benefit of the On-X valve’s unique design with high-risk aortic patients,” said Clyde Baker, On-X LTI’s president. “The results emphasize the ability of the On-X valve to tolerate an inconsistent INR level, without a significant increase in thromboembolic events that are exhibited by other currently available mechanical valves.”
Until the completion and analysis of study data, On-X Life Technologies, Inc., continues to recommend standard anticoagulation therapy as presently prescribed by various professional societies for the On-X valve.
About On-X LTI
On-X® Life Technologies (On-X LTI) develops heart valve replacements that significantly improve the quality of life of patients. Jack Bokros, Ph.D., and his associates founded On-X LTI in 1994 to further advance prosthetic heart valve technology by capitalizing on their new form of pyrolytic carbon. The company has FDA, CE and Japanese approval for sale of the On-X® valve. On-X LTI also provides contract-manufacturing services utilizing its patented pyrolytic carbon to manufacturers of other medical products, including orthopedic joint and spine prostheses. Headquartered in Austin, Texas, On-X LTI is a privately held company. More information is located at www.onxlti.com.
On-X is a registered trademark of On-X Life Technologies, Inc. All other trademarks mentioned herein belong to their respective companies.
On-X Life Technologies, Inc.
Clyde Baker, 512-339-8000 ext. 269