By David Hilzenrath, KFF Health News
This story also ran on The Washington Post.
When the FDA was deciding whether to approve the drug Tavneos several years ago to treat a set of rare autoimmune diseases, agency experts argued that would be a mistake, citing “limited safety data.” The FDA approved it anyway in 2021, with a proviso: the manufacturer had to conduct an additional years-long safety study once the drug was on the market.
Today, like many similar “postmarket” studies mandated by the FDA, that additional study is delayed. As of last fall, only 21 of the planned 300 patients had been enrolled, the FDA said. Meanwhile, the FDA has identified dozens of cases of liver damage “possibly” or “probably causally associated” with the drug — one of the risks the postmarket study was meant to evaluate.
A KFF Health News analysis of FDA data found hundreds of postmarket studies listed as delayed — in some cases by more than a decade, or where the manufacturer was still developing a plan for the study. As a result, patients, doctors and others can be left in the dark about the risks and benefits of drugs and devices already on the market.
Postmarket study requirements “have often proven toothless,” said cardiologist Sanket Dhruva, an associate professor of medicine at the University of California-San Francisco.
An FDA database downloaded by KFF Health News in August showed almost 600 postmarket studies running behind schedule, involving almost 350 products. More than 250 of those originally had final reports due before July 31, 2026.
Trump administration policy changes designed to speed drugs through FDA review could put more weight on postmarket studies, researchers say. In February, FDA leaders announced that “the default requirement” for approvals will be one clinical trial instead of two. Reducing pre-approval testing “will inevitably put a lot of pressure on the post-approval system,” said Aaron Kesselheim, a professor at Harvard Medical School.
A Department of Health and Human Services spokesperson said postmarket studies can experience delays for legitimate reasons, and that a delay “should not be treated as evidence that a product has an unresolved safety or effectiveness issue.”
Products with delayed studies include the CustomFlex Artificial Iris (zero patients enrolled in a pediatric study accepted in 2019), Paxlovid (a study on safety in pregnant women missed its 2024 completion target), the Scandinavian Total Ankle Replacement system (fewer than a third of planned patients enrolled, with dozens of “reoperations” or “removals” among them), and Oxaydo, an opioid painkiller whose maker received an FDA “failure to respond letter” in 2022 before the drug was discontinued.
“Medicare and Medicaid spent more than $18 billion from 2018 to 2021 for accelerated approval drugs with incomplete confirmatory trials past their original planned completion dates,” the HHS Office of Inspector General estimated in 2022.
Amgen, which makes Tavneos, is fighting an FDA effort to pull the drug from the market after the agency alleged a clinical trial’s results were “manipulated” by ChemoCentryx, the company Amgen acquired in 2022. Amgen has denied the results were manipulated. The European Union recently revoked its approval of Tavneos. Tavneos generated $459 million in global sales last year.
Read more from KFF Health News, an editorially independent program of KFF, the independent source for health policy research, polling and journalism.