Since the passage of the 21 st Century Cures Act in 2016, Food and Drug Administration (FDA) approvals for new medical products have relied on fewer studies, according to a study published August 26, 2026 in the open access journal PLOS One by researchers from the Stanford University School of Medicine Clinical Excellence Research Center, Oregon State University, and UCLA, US.
The 21 st Century Cures Act was a legislative effort to speed up development and review of new medical products such as pharmaceuticals. Although the FDA had been allowed to approve new medications on the basis of a single trial when those trials are considered of high enough quality, the Act enhanced the FDA’s ability to accept single trials when approving new products.
To better understand how this policy might have affected subsequent drug approvals, the authors of this study reviewed 6,763 studies linked to Novel Drug Approval by the FDA between January 1, 2016 and December 21, 2024, documented on clinicaltrials.gov , to capture the number of studies relied on both before and after the Act’s passage. They examined how many clinical trials each approval relied upon, the sources of trial funding, and when the final trial results were reported.
According to lead author Aditya Narayan, the mean number of studies per approval fell from 3.41 in 2016 to 1.5 by 2022, with 59.1 percent of drugs in 2016 approved with three or more trials compared to only 11.8 percent of drugs in 2021. By 2024, 69.4 percent of products were approved based on only a single trial. Senior author Robert Kaplan explained “Replication is a cornerstone of the scientific method. The growing practice of approving medications on the basis of a single trial is concerning, as it allows products to reach the market without independent confirmation of the findings.” The percentage of industry-funded studies also increased, with 44.6 percent of trials industry funded in 2016, compared to 80.4 percent by 2024. The average time it took to publish clinical trial results was well over a year.
While the review establishes an association between the Cures Act passage and the decrease in studies, it cannot assure the relation is causal. The study did not address whether the changes increase risks to patients, and the authors did not have access to information about drugs that were not approved by the FDA in the same time period for comparison. Based on these results, the authors suggest that the Cures Act might help speed up time to new drug approvals, though the reliance on single studies also raises concerns about the safety and effectiveness of the new therapeutics.
In your coverage, please use this URL to provide access to the freely available article in PLOS One : https://plos.io/45XtJAW
Citation: Narayan A, Irvin VL, Koong AJ, Song S, Kaplan RM (2026) Changes in evidence used for FDA Novel Drug Approvals: 2016-2024. PLoS One 21(8): e0342878. https://doi.org/10.1371/journal.pone.0342878
Author countries: US
Funding: The author(s) received no specific funding for this work.
PLOS One
Observational study
People
Changes in evidence used for FDA Novel Drug Approvals: 2016-2024
26-Aug-2026
The authors have declared that no competing interests exist.