When the Trump administration brutally cut federal funding for biomedical research earlier this year, at least 383 clinical trials that were already in progress were abruptly cancelled, cutting off over 74,000 trial participants from their experimental treatments, monitoring, or follow-ups, according to a study published today in JAMA Internal Medicine.
The study, led by researchers at Harvard, fills a knowledge gap of how the Trump administration's research funding cuts affected clinical trials specifically. It makes clear not just the wastefulness and inefficiency of the cuts but also the deep ethical violations, JAMA Internal Medicine editors wrote in an accompanying editor's note.
In March, the National Institutes of Health, under the control of the Trump administration, announced that it would cancel $1.8 billion in grant funding that wasn't aligned with the administration's priorities. The Harvard researchers, led by health care policy expert Anupam Jena, used an NIH database and a federal accountability tracking tool to find grants supporting clinical trials that were active as of February 28 but had been terminated by August 15.
During that time, there were 11,008 trials funded and in various stages. Of those, 383 were terminated. Some cancelled trials were still in early phases before recruiting participants (14 percent), some were in the process of recruiting participants and hadn't yet fully begun (34.5 percent), a sliver were enrolling participants by invitation (3.4 percent), and some were completed (36 percent). Then there were the trials that were in progress -- active, no longer recruiting -- about 11 percent, 43 trials. In this stage, participants were in the process of receiving interventions. In the 43 trials, there were 74,311 trial participants collectively.
Of the 383 cancelled trials, 118 (31 percent) were for cancers, 97 (25 percent) were for infectious diseases, 48 (12.5 percent) were for reproductive health, and 47 (12 percent) were for mental health.
"A betrayal"
Jena and colleagues examined the greater context, comparing the number of cancelled trials in each treatment category to the total number of all funded trials in those categories. For instance, while cancer trials made up 30 percent of the 383 cancelled trials, the 118 cancelled cancer trials accounted for only 2.7 percent of the total 4,424 cancer trials funded in the study period. The cancelled infectious disease trials, on the other hand, accounted for over 14 percent of all infectious disease trials funded (675). The categories most disproportionately affected were infectious diseases, respiratory diseases, and cardiovascular diseases.
The researchers also looked at the purpose of the cancelled trials -- for instance, for treatment of a disease, prevention, supportive care, or diagnostics. Of the 383, 140 were for treatments and 123 were for prevention.
The authors note that they weren't able to determine the stated reasons for the cancellations (if any) or compare this year's trial cancellations to trends from previous years, which could offer more context to the cuts. There simply isn't the same comprehensive data on clinical trial cancellations for past years, the authors said, noting "termination of federal grant funding was rare prior to 2025."
In the accompanying editor's note, Teva Brender and Cary Gross blasted the revealed cancellations. To cancel trials already underway is to "squander participants' and investigators' valuable time, effort, and resources," they write, since there have already been "substantive sunk costs." It also "stifles scientific discovery and innovation."
But "there is a more direct and sobering impact of premature and scientifically unjustifiable trial terminations: the violation of foundational ethical principles of human participant research," they write. "First and foremost, it is betrayal of the fundamental principles of informed consent for research." And "participants who have been exposed to an intervention in the context of a trial may be harmed by its premature withdrawal or inadequate follow-up and monitoring for adverse effects."
Over 74,000 trial participants entrusted researchers with "their health and hope," but even if the trial funding is restored -- as it may be for some -- it would "at best mitigate the harms."