The Regulatory Perspective

Dorothy B. Abel discusses the FDA's considerations and its role regarding trial data.

By Dorothy B. Abel

Endovascular Today: Based on your experience at the FDA, how reliable is the US IDE data?

Dorothy B. Abel: I believe that the US data are collected under relatively perfect circumstances and that the data accurately reflect the performance of the device when used within the context of a clinical study. We require a clearly defined investigational plan, with specified enrollment criteria, adverse event definitions, follow-up requirements, and analysis plans. The data are monitored not only by the sponsor of the study, but also by the FDA. The data are reliable, but may not always represent real world use, as such strict criteria are generally not applied after the device is widely available.

Endovascular Today: What do you mean when you say this data has been collected under "perfect circumstances?"

Dorothy B. Abel: I am referring to the experience level of the physicians who participate in the studies, as well as the clearly defined study plan. Also, it is generally accepted that patients fare better when they are participating in a study. For one thing, they are followed more closely.

Endovascular Today: How closely can we compare the results of EVAR-2 with the US IDE data?

Dorothy B. Abel: The EVAR-2 study was a level one study, as it was randomized, with long-term freedom from mortality as the primary response variable. Our US IDEs are not randomized, are designed to evaluate multiple response variables, and have a 1-year primary endpoint. Most of the US studies are designed to enroll patients who are eligible for surgical repair, but even the high-risk patients who are in our studies do not seem to be as high risk as the EVAR-2 patients. I guess I would say that the data really are not easily compared.

Endovascular Today: What are your thoughts on randomized trials in the US for high-risk endovascular aneurysm repair patients?

Dorothy B. Abel: We would not require randomized studies for high-risk patients in order to obtain marketing clearance for a device. Randomization is not necessary to demonstrate that a device would be a reasonable treatment option for these patients. Such studies may be appropriate to answer other questions, such as cost effectiveness or the optimal treatment for a specific subgroup of patients, but this falls outside of the FDA purview.

Endovascular Today: Based on the data that were presented to the FDA and the additional data that you have seen, what is your opinion regarding the endovascular treatment of both high- and good-risk patients?

Dorothy B. Abel: I think that all our studies can show is that endovascular repair is a treatment option. The individual clinician needs to look at the individual patient and decide with them whether it is the best option for that patient. I think endovascular aneurysm repair should be an option for every patient.

Endovascular Today: The EVAR-2 investigators have suggested that the Lifeline Registry may not have included all of the patient data. What is your opinion on this possibility?

Dorothy B. Abel: That is simply not the case. Lifeline has all of the audited data from clinical studies. It is not a voluntary registry like Eurostar, where participants pick and choose the patients and the data to submit.

Endovascular Today: Are there further studies that you would like to see conducted regarding endovascular aneurysm repair?

Dorothy B. Abel: There will always be a need to get additional data. Perhaps we need more data regarding specific patient populations. The more studies we have, the more information the doctors have to optimize individual patient care.

Dorothy B. Abel is a Regulatory Review Scientist with the US FDA Center for Devices and Radiological Health in Rockville, Maryland.ÊMs. Abel may be reached at (301) 443-8262, ext. 165;


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Endovascular Today is a publication dedicated to bringing you comprehensive coverage of all the latest technology, techniques, and developments in the endovascular field. Our Editorial Advisory Board is composed of the top endovascular specialists, including interventional cardiologists, interventional radiologists, vascular surgeons, neurologists, and vascular medicine practitioners, and our publication is read by an audience of more than 22,000 members of the endovascular community.