Closer To Understanding Potential For Reducing AntiCoags With Completed Enrollment In On-X® Heart Valve Study

On X pure pyrolytic carbon valveIn short

The design of the On-X valve from On-X® Life Technologies, Inc. means theoretical reduction in blood damage, which is associated with clot production. A sizeable study, tagged PROACT, is underway, one patient cohort of which hopes to establish whether Low-Risk Aortic Valve and Mitral Valve Patient Groups receiving an On-X valve can be safely maintained with aspirin and clopidogrel (Plavix®). This low-risk cohort has now completed enrollment.


By utilising On-X’s proprietary pure pyrolytic carbon in the manufacture of its valves, the company claims its devices feature a more thromboresistant surface. Additionally the comparatively high strength of the material facilitates design features resulting in the prosthesis acting more like a natural valve in its treatment of blood. By reducing turbulence and blood damage the valve reportedly significantly reduces the potential for life-threatening blood clots. This could mean a reduction in the use of anticoagulant drugs, a hypothesis this study arm will test.

The Prospective Randomized On-X Valve Anticoagulation Trial (PROACT) was initiated with US FDA approval in 2006 and is being conducted at 36 centers throughout the United States and Canada.

The Low-Risk Patient Group of the PROACT trial is comprised of patients requiring aortic valve replacement who meet the low-risk criteria established by the study’s protocol, which was reviewed and approved by the FDA under Investigational Device Exemption (IDE) rules. This is the only FDA-approved study using aspirin and clopidogrel as the anticoagulant for aortic valve patients receiving a mechanical valve. The Mitral Valve Patient Group follows patients taking reduced warfarin. The unique and innovative design and material features of the On-X valve, combined with the previously established clinical data for the valve, made conduction of the trial possible.

Importantly, 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.

Physician comments

“I believe the completion of enrollment for the low risk ASA/clopidogrel group points to a day when we surgeons will be authorized to offer this option more widely,” said Allen Henry Graeve, M.D., Site Investigator at Tacoma General Hospital in Tacoma, Washington. “I have two patients now on ASA/Plavix for six years and another two on it for five years. All are complication free and very happy to take two pills a day, not have their blood checked, and be blessed with a permanent valve solution. One is very young and works abroad – he’s so grateful to be free of complications and Coumadin®.”

Company comments

“The completion of enrollment for the low-risk aspirin and clopidogrel patient group is a very positive sign,” said John Ely, Executive Vice President of Regulatory Affairs and Quality Assurance for On-X Life Technologies, Inc. and the primary coordinator of the PROACT trial. “It will allow us to more accurately project event rates and follow-up needs as we progress toward the study’s completion. When the longer-term follow-up data are collected, analyzed and reviewed, we will be able to determine whether selected recipients of the On-X valve in the aortic position can be safely managed without warfarin anticoagulation. If that is the case, it will be an important breakthrough for prosthetic valve recipients.”

“On-X LTI previously announced it submitted to the FDA a request to change the Instructions for Use for the On-X valve to include the opportunity to permit reduction in patient anticoagulation for all aortic patients,” said Ely. “Similarly, our intent is to do this for the Low-Risk Patient Group once the data has sufficient statistical significance, which will come with time. The completion of enrollment for this most important aspirin and Plavix group is a major milestone needed to achieve that objective.”

Source: On-X Life Technologies, Inc., Business Wire

Note:  Plavix is a registered trademark of Sanofi-Aventis. Coumadin is a registered trademark of Bristol-Myers Squibb.