(Story updated with FDA comment at 4:35 p.m. ET.)
Medical-device makers are slow to complete studies on the safety and effectiveness of medical devices such as pacemakers, heart valves and stents after the products enter the market, according to new research. Some are never completed at all.
Researchers reviewed post-market clinical studies for more than two dozen high-risk medical devices introduced in 2010 and 2011. The majority weren't finished. That included 33 marketplace studies that the Food and Drug Administration required when it approved the device.
The results, published Tuesday in JAMA, add to other studies that raise concerns about the quality of clinical research required by regulators for high-risk devices. The concerns come as Congress debates new legislation known as the 21st Century Cures Act, which has been criticized for relaxing safety standards for medical devices by allowing less rigorous evaluation before approval.
The bill, which includes $9.3 billion over five years for the National Institutes of Health and $550 million for the FDA, cleared the House in July. Device manufacturers have praised the legislation for its potential to make the path to market for new products faster and less expensive.
Of the 33 marketplace studies required by the FDA, researchers identified six that had been completed as of October last year. Out of another 171 studies launched by manufacturers after devices entered the market, 20 had yielded results.
“FDA often requires device manufacturers to conduct post-marketing safety studies on high-risk devices and can take action to ensure that manufacturers meet their commitments,” FDA spokeswoman Deborah Kotz said in a written statement. Some studies require more than the three to five years included in the JAMA analysis before they will be completed, she said.
The FDA uses additional sources to monitor safety, including adverse-event reporting and disease registries. The agency also publicly reports on mandated studies, she said.
The lack of results leaves doctors and patients with the safety information from studies done before the devices were approved. Those studies are often small and limited in duration and do not always employ randomized, controlled trials, said Dr. Joseph Ross of Yale University, one of the new study's four authors. The researchers also reviewed 30 studies that provided the primary evidence for approval, known as pivotal studies. The median number of patients in those studies was 241, and the median duration was three months.
"We found that pivotal studies generally enrolled fewer than 300 patients and were often designed without blinding, comparators or primary endpoint follow-up exceeding one year," the researchers wrote.
With such limited results, post-market research can provide valuable information, Ross said. Once devices are “out in the world, being used by thousands upon millions of people” more safety information can be collected to inform doctors' and patients' choices, he said.
Some studies will not be finished for another one to eight years for devices that entered the market in the last three to five years, Ross and his colleagues found.
Researchers identified 10 devices that were recalled, though just one device was ultimately pulled from the market. About three-quarters of the devices studied were implanted in patients. Nine were deemed “life-saving.”
Timely results are critically important because devices are often replaced with newer versions after five to seven years. “The newest, greatest stent or defibrillator or hip is replaced by the next one in the world of medical device technology,” and research becomes obsolete, Ross said.
Regulators also rely on post-market studies so they can bring promising devices to market quickly. But Ross said the results of his study suggest a lack of coordination in post-market oversight.
New rules in the 21st Century Cures Act would make regulators even more dependent on post-market research with less rigorous evaluation before approval, he said. “If we do more of this, I am worried that we're going to know even less.”
The legislation has been criticized for weakening regulatory oversight. “The device industry may stand to benefit from this legislation, but the health of the public does not,” two cardiologists wrote in the New York Times.
The doctors criticized the bill for its dependence on research conducted after devices enter the market. “Unfortunately, such studies are often delayed months to years after a device is approved. Many are never completed and even when they are, their findings are often not publicly available.”
The legislation would “truncate” device approval, which is risky when marketplace research is underdeveloped and yet critical to understanding device safety, said Dr. Aaron Kesselheim of Harvard University's School of Public Health, who studies drug and device development and approval.
Kesselheim and Dr. Jerry Avorn wrote in the New England Journal of Medicine that the Cures Act also would weaken oversight because manufacturers would be able to win FDA approval with results from case studies and registries rather than clinical trials.
“That's going to increase risk to patients.” Kesselheim said. “You'll increase the risk of unsafe or ineffective devices being widely used in patients.”