In 2024, the US Food and Drug Administration (FDA) approved 69.4% of new drugs based on evidence from a single study
In 2024, the US Food and Drug Administration (FDA) approved 69.4% of new drugs based on evidence from a single study
In an article published on August 26, the authors examined every new FDA approval from 2016–2024 and the 6 763 studies associated with them. Over this period, the mean number of studies supporting each FDA approval fell from 3.41 to 1.39.
The authors extracted studies that the agency explicitly relied on from FDA review packages, along with studies cited in the rationale for each decision. In February, FDA leadership proposed treating one decisive study as the standard basis for approval. In the data collected by the authors, a single study had already become the most common basis for approval by 2017. In 2024, three or more studies supported 5.6% of approved drugs.
The authors explain that the historical rationale for requiring two studies was reproducibility:
“Requiring at least two studies for approval reflects a fundamental scientific principle: reproducibility.”
The strength of the evidence also depends on trial design, including the treatment comparator, the method used to assign participants to groups, and the outcome that was measured. In an independent analysis of 49 new drugs approved by the FDA in 2020, 28 drugs (57.1%) were approved on the basis of one pivotal trial, defined as a trial on which the FDA relied in making its decision. Among the 75 pivotal trials, 76% randomly assigned participants to groups, while 45.3% used a surrogate as the primary endpoint, meaning a measure used in place of an outcome that matters directly to patients.
Among studies with results published in the public ClinicalTrials.gov registry, the mean interval between collection of primary endpoint data and publication of the results exceeded one year in every year examined. The statement “the FDA approved the drug” therefore raises specific factual questions: how many pivotal trials supported the decision, what the treatment was compared with, which outcomes were measured, and when the results became publicly available.