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DePuy, Federal Food Drug and Cosmetic Act, Food & Drug Administration, Hip Replacement, Institute of Medicine, Medical device, New England Journal of Medicine, UNited States
Medical Devices — Balancing Regulation and Innovation
Gregory D. Curfman, M.D., and Rita F. Redberg, M.D.
Many Americans benefit from the implantation of medical devices, such as artificial joints and lifesaving defibrillators. Tragically, many also suffer or even die from complications related to medical devices that were never studied in clinical trials before being implanted in patients. As devices have evolved and become more complex, our device-approval system has become incapable of assuring safety and effectiveness. The system we use today was created 35 years ago in an era of much simpler and fewer devices, and it is now outdated.
A recent, but not rare, example provides a cautionary tale about the challenges of ensuring that complex medical devices are both effective and safe. Osteoarthritis of the hip joint is a common and debilitating disorder. Each year, nearly a quarter of a million patients with advanced painful arthritis receive a total hip replacement in the hope that it will restore mobility and improve their quality of life.1 Conventional artificial hip implants consist of a metal ball inserted into a plastic cup. In 2005, a new metal-on-metal design was introduced in which both components were made from a metal alloy. The design was touted as a major innovation that would improve durability and reduce the risk of hip dislocation — advantages that were especially appealing to younger patients but were never tested.
One metal-on-metal design is the DePuy (Johnson & Johnson) ASR XL Acetabular System, which was introduced into the U.S. market in 2005. The ASR was cleared by a Food and Drug Administration (FDA) process known as 510(k), which refers to the section of the 1976 Medical Device Amendments to the Federal Food, Drug, and Cosmetic Act that created it. Under that section, the criterion for clearance of a new medical device is that it be “substantially equivalent” to an already-marketed device (a “predicate”); clinical data are not required.
The ASR was constructed by borrowing a metal alloy cup from a different hip device known as the ASR Hip Resurfacing System and retrofitting it onto a standard hip implant. The manufacturer successfully made the case that the re-engineered implant was “substantially equivalent” to a predicate device. Its marketing clearance was therefore based not on clinical trials or other clinical data but on bench testing in a laboratory, which was inadequate to simulate the stresses that would be placed on it in patients’ bodies.
It soon became clear that the device failed at the astonishing rate of at least one in eight. According to a recent report presented at the British Hip Society Annual Conference, 21% of these hips have had to be replaced (revised) by 4 years after implantation, and the revision rate rises to 49% at 6 years, as compared with 12 to 15% at 5 years for other devices.2 Failure appears to be due to erosion of the metal in the articular surfaces and migration of metallic particles into the surrounding tissues and the bloodstream. Thus, the innovation led to tragedy for many patients.3 Before it was recalled in 2010, the ASR had been implanted in nearly 100,000 patients, and the result was a public health nightmare.
The ASR is a class III device — the FDA’s highest risk classification. Clearance through the 510(k) process is especially inappropriate for such risky devices. Congress envisioned that class III devices would be approved through the more stringent premarket approval (PMA) process, which does require clinical testing, and the Safe Medical Devices Act of 1990 requires that the FDA either use the PMA process for class III devices or reclassify them in a lower-risk category. Despite the clear intent of Congress, high-risk devices continue to slip by this requirement.
On July 20, 2011, the U.S. House Energy and Commerce Subcommittee on Oversight and Investigations held a hearing entitled “Medical Device Regulation: Impact on American Patients, Innovation, and Jobs.” The subcommittee’s chairman, Congressman Cliff Stearns (R-FL), argued that FDA regulation of medical devices is too burdensome, stifles innovation, and drives device manufacturers overseas. But the disastrous outcomes of the use of DePuy ASRs show that rushing untested and potentially dangerous medical devices into the marketplace carries serious risks; our regulators should not be in the business of creating jobs in the manufacture of dangerous devices.
On July 29, 2011, the Institute of Medicine (IOM) released an FDA-commissioned report on the 510(k) clearance process.4,5 The report concluded that it was impossible for 510(k) clearance to assure safety and effectiveness, because it assesses neither, instead establishing only “substantial equivalence” to an existing device. The report therefore recommended that 510(k) clearance be eliminated. In addition, it recommended monitoring medical devices throughout their life cycle, especially during the postmarketing period. Despite its reasonable (and relatively modest) recommendations, the report has been aggressively attacked by the device industry and by politicians from states where device companies are located. In fact, the attacks began even before the report was released, which is highly unusual for an IOM report.
We believe that the IOM report is insightful, judicious, sensible, and long overdue. The 510(k) clearance process was established 35 years ago, and although it may have been a reasonable approach then, it surely is not today. We support the IOM committee’s recommendation that the 510(k) process be replaced with an evaluation of safety and effectiveness. It is important to maintain and encourage innovation in medical devices. But true innovation requires that safety and effectiveness be proven by scientific study in clinical trials.
Unfortunately, the FDA leadership has already suggested that it does not intend to implement this key recommendation of the report, although it may be open to other changes. As the best long-term improvements are contemplated, there are important steps that the agency can take now.
First, the use of 510(k) clearance for class III devices should stop, as Congress made clear 20 years ago. A substantial equivalence standard for clearance of such complex devices is untenable.
Second, the use of multiple predicates in 510(k) clearance should be eliminated. Now a device may be cleared if it is found to be substantially equivalent to an existing device that was cleared, in turn, by being found substantially equivalent to another device, and so on. This tenuous process should be discontinued.
Third, as was recommended by the IOM committee, a formal system of postmarketing surveillance for medical devices should be put in place. Strong, mandatory, and transparent postmarketing data, in registries, allow rapid identification of serious problems that may emerge after approval. Careful tracking of every patient with a high-risk device is a crucial step for ensuring patient safety and avoiding nightmare scenarios.
We strongly believe that, in the interest of advancing human health, patients must have easy access to innovative medical devices and that the approval process needs to be sensible and efficient. But no one’s interest is served by putting defective medical devices onto the market where they cause harm to patients, waste health care dollars, and may kill jobs when they are withdrawn. It is essential that the FDA be adequately funded to carry out its mission to ensure the safety and effectiveness of medical devices. The IOM report charts a path that is right for the future, and despite well-financed outside pressures, we urge the FDA to initiate an action plan with congressional support to adopt these important recommendations.
Disclosure forms provided by the authors are available with the full text of this article at NEJM.org.
This article (10.1056/NEJMp1109094) was published on August 10, 2011, at NEJM.org.
Source Information
Dr. Curfman is the Executive Editor of the Journal, and Dr. Redberg is the Editor of the Archives of Internal Medicine, San Francisco.
References
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