Thank you for the opportunity to speak today. I am Dr. Christina Silcox, I have a PhD in Medical Engineering and Medical Physics from MIT and Harvard Medical School, and I am a senior fellow at the National Center for Health Research. Our research center scrutinizes scientific and medical data and provides objective health information to patients, providers and policy makers. These are the perspectives I bring here today. We do not accept funding from pharmaceutical or device companies and so I have no conflicts of interest.
We support the FDA’s recommendation that More-than-Minimally Manipulated (MMM) Allograft Heart Valves be classified as Class 3 devices and therefore subject to the premarket approval process. All other types of heart valves under the oversight of the Center for Devices and Radiological Health at the FDA are classified as class 3. There is no reason that these heart valves should be an exception.
MMM allograft heart valves are indisputably used to support and sustain human life and are of substantial importance in preventing impairment of human health, which is the definition of a Class 3 device.
Only Class 3 devices are subject to pre-market manufacturing process review. Manufacturing processes are critical to the safety of this device. In addition, the effectiveness of MMM heart valves are also highly dependent on the manufacturing process, affecting the performance and longevity of the valve and the likelihood of immune rejection.
There is currently insufficient information to determine all the general and special controls that would be necessary to provide reasonable assurance of the safety and effectiveness of this device in order to classify the device as Class 2.
Certainly, clinical trials would be one type of control needed. Currently, most of the information about these devices consists of small studies (under 50 subjects per valve type), often funded by a single device company. None of the studies were randomized. Half did not include a control group.
Few studies looked at the immunologic responses of the MMM valves, and only two of those did a comparison of MMM valves vs standard allograft valves. Follow-up of all four immunological studies was 1 year or less – which is not enough to tell us how safe or effective these valves are.
Most studies of MMM heart valves have focused only on the resulting heart valve function. As a result, we have almost no information about other potential side effects.
Post-market study data from the single currently-approved MMM allograft heart valve is not currently available, and when completed it will focus on pulmonary valve replacement, which studies suggest is much less immunogenic than aortic valve replacement.
To summarize – heart valves are high risk devices and that’s why all other heart valves regulated by the Center for Devices are Class 3. Given these MMM allograft heart valves are relatively new, with limited information available about exactly how the processing changes the tissue, we do not know enough to control potential risks with special controls. For example, mechanical valves have been used in humans for over 50 years but are still Class 3 because a 510(k) with special controls is not sufficient to protect patients’ lives.
We recommend the Advisory Panel vote to classify these devices as Class 3, which will save lives by ensuring the safety and effectiveness of these devices be proven in well-designed clinical trials and pre-market inspections.