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# Study Finds Drug Approvals Increasingly Rely on Fewer Trials
- URL: https://www.fdaweb.com/study-finds-drug-approvals-increasingly-rely-on-fewer-trials/
- Published: 2026-08-28T12:00:00.000Z
- Updated: 2026-09-14T12:05:34.000Z
- Author: David McFarland
- Tags: Drugs, #legacy-id-D5161701

FDA’s approval of new drugs is increasingly being supported by fewer clinical studies, while industry-sponsored research represents a much larger share of the evidence behind those approvals, according to a [new analysis](https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0342878&ref=fdaweb.com) published in PLOS One.

Researchers from Stanford University, Oregon State University, UCLA and other institutions looked at approvals following the passage of the 21st Century Cures Act in 2016, which was intended to speed up development and review of new medical products. While FDA had previously been permitted to approve new drugs based on a single trial, the Act enhanced this ability to accept single trials when approving new products. 

To better understand how this policy might have affected subsequent drug approvals, the study authors reviewed 6,763 studies linked to novel drug approval between 2016 and 2024 to document 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% of drugs in 2016 approved with three or more trials compared to only 12% in 2021\. By 2024, 69% 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 45% being industry-funded in 2016, compared to 80% by 2024\. And the average time it took to publish clinical trial results was well over a year. 

The study authors note that while their examination establishes an association between the Cures Act passage and the decrease in studies, they 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 FDA in the same time period for comparison.