Nearly 400 clinical trials testing treatments for cancer, heart disease, infectious diseases, and other conditions have been disrupted by grant terminations at the National Institutes of Health, affecting more than 74,000 research participants, according to a new study published today in JAMA Internal Medicine.
The research reveals that between February 28 and August 15, 2025, approximately one in 30 NIH-funded clinical trials—383 out of 11,008 total studies—lost federal funding following widespread cuts under the Trump administration.
Taxpayer money had already been spent on canceled grants before their termination. These studies are now unlikely to yield publishable results, given the incomplete nature of data collection.
The funding cuts did not affect all areas of research equally. Trials studying infectious diseases were hit hardest, with 14.4% losing funding—the highest rate among all disease categories examined. Prevention-focused trials also suffered disproportionately, with 8.4% terminated compared to just 2% of basic science trials.
Behavioral intervention studies faced a 5% termination rate, while cancer research, despite having the largest number of affected trials overall at 118, saw a comparatively lower 2.7% termination rate. Reproductive health and neurological disorder trials experienced the lowest disruption rates at 2.2%.
Trials conducted outside the United States were nearly twice as likely to lose funding compared to U.S.-based studies—5.8% versus 3.4%. Among domestic trials, those in the Northeast faced the highest termination rate at 6.3%, while multiregional trials saw no funding cuts.
Of the 383 affected trials, 134 were actively recruiting participants when funding was terminated, while 43 were in the active phase with patients already receiving interventions. An additional 53 trials had not yet begun recruiting, potentially delaying or permanently halting new research.
For the 43 trials classified as “active, not recruiting” at the time of termination, where 74,311 individuals had already been enrolled. Some patients could have lost access to medication or been left with unmonitored medical device implants, while others participated in studies whose results may never be published.
The scope of the 2025 terminations is unprecedented. Earlier analyses found that 694 NIH grants were terminated between February 28 and April 8, totaling $1.81 billion in value, with 30% of that funding not yet expended. By September, a separate study identified 760 terminated grants, including more than $1.3 billion in Massachusetts alone.
The National Institute of Mental Health and the National Institute on Minority Health and Health Disparities experienced the largest numbers of terminated grants, with 128 and 77, respectively. The National Institute of Allergy and Infectious Diseases and the minority health institute accounted for the most terminated funding at $506 million and $224 million.
