The National Cancer Institute has quietly moved a familiar and polarizing drug into its preclinical pipeline: ivermectin, long known as a popular dewormer for horses and a standard antiparasitic in humans. The decision to test its ability to kill cancer cells has unsettled many career scientists who see echoes of the COVID era’s most contentious drug debates. At stake is not only whether this decades‑old medicine has any real future in oncology, but also how federal research priorities respond to political pressure and public mythmaking.
The early lab data are intriguing enough to justify curiosity, yet far too thin to support the sweeping claims already circulating online. I see the ivermectin project as a stress test of the cancer research system itself: can it explore a controversial idea without feeding misinformation, and can it shut the door quickly if the science does not hold up?
Inside NCI’s ivermectin experiment
The National Cancer Institute, the largest of the NIH’s 27 branches, has launched a preclinical study that exposes cancer cells to ivermectin and measures whether the drug can slow their growth or trigger cell death. Researchers are working in vitro, not in patients, which means the experiments are closer to a chemistry screen than a treatment trial. The work builds on a recent laboratory project funded by NCI that found antitumor effects in certain cell lines, suggesting that the drug might interfere with pathways cancer cells rely on to survive, but without any proof that those effects can be reproduced safely in humans at realistic doses, as described in a detailed report on antitumor effects.
Officials have framed the effort as part of a broader push to evaluate inexpensive, off‑patent compounds that might be repurposed for oncology. In that sense, ivermectin is one tile in a much larger mosaic of exploratory screens, not a flagship program. Yet the drug’s notoriety during the pandemic, when it was promoted far beyond the evidence for COVID, means this particular tile glows brighter than the rest. Even a routine cell‑culture assay can look like an endorsement once it is filtered through social media feeds and advocacy networks that have already cast ivermectin as a miracle cure in waiting.
Why many scientists are alarmed
For veteran cancer researchers, the concern is less about running a single lab experiment and more about what it signals about judgment. In internal discussions described by one account, some career staff questioned why NCI would prioritize a molecule that has become a cultural lightning rod when other repurposed drugs with stronger mechanistic data are still waiting in line. One prominent oncologist, Anthony Letai, has been quoted reacting to the ivermectin project with a blunt assessment, captured in a STAT Plus excerpt, calling the idea “absurd” and warning that it risks undermining confidence in NCI’s scientific rigor.
There is also a practical fear that even a modestly positive lab signal will be misread as a green light for off‑label prescribing. During the COVID pandemic, ivermectin’s popularity surged far beyond its approved uses, driven by unsupported claims that it could prevent or treat infection. That history is fresh in the minds of public health officials who now see the same drug being tested against cancer cells inside The National Cancer Institute, a move documented in a Washington policy piece on NCI’s role. To them, the risk is not just wasted lab time, but a new wave of patients abandoning proven therapies in favor of a lab‑bench curiosity.
What the preclinical evidence actually shows
Supporters of the study point to earlier laboratory work suggesting that ivermectin can push cancer cells toward programmed death and disrupt signaling pathways that tumors use to grow. Previous laboratory research has shown that the drug can promote apoptosis in certain malignancies, a finding summarized in a review of preclinical research. Following a similar drug development approach, preclinical studies published in 2020 explored whether ivermectin could be combined with standard chemotherapy or targeted agents, with some cell lines showing increased sensitivity when the drug was added to the mix.
Yet those same reports emphasize the yawning gap between killing cells in a dish and helping patients in a clinic. The concentrations needed to see robust antitumor effects in vitro often exceed what can be achieved safely in human blood, and the drug’s behavior in complex tissues is far harder to predict than in a controlled culture flask. One oncology commentary, framed as a cautionary note from a practicing specialist, stressed that these early signals do not establish that ivermectin is a viable cancer treatment and urged colleagues to resist pressure from patients who arrive with internet printouts, a stance detailed in an analysis of preclinical enthusiasm.
Oncologists, patients, and the trust gap
Clinicians are already feeling the downstream effects of ivermectin’s reputation. In a survey highlighted by one cancer news outlet, 22 respondents expressed that they do not recommend ivermectin use for cancer treatment, while eight said they were unsure or did not have enough information to advise either way, according to a report on oncologist views. That pattern suggests a profession that is both skeptical and wary, trying to balance open‑mindedness about repurposed drugs with a duty to protect patients from unproven regimens.
Patients, meanwhile, are navigating a fragmented information landscape where ivermectin is often presented as a suppressed cure rather than an unproven hypothesis. Persistent unsupported claims about ivermectin’s effectiveness in treating a range of diseases, including cancer and COVID‑19, have been documented by health misinformation trackers who note that such narratives are now embedded in online communities and local political debates, as detailed in a review of persistent myths. When NCI steps into this environment, even a cautious preclinical study can be weaponized as “proof” that the establishment knew all along.
Politics, RFK Jr., and taxpayer scrutiny
The ivermectin project is unfolding in a charged political context where federal health agencies are under intense scrutiny from both skeptics and advocates of aggressive alternative therapies. One detailed account of the study’s origins notes that it is funded through NIH mechanisms at a time when Dewormer ivermectin has become a symbol of resistance to mainstream COVID guidance, and it highlights how RFK Jr. and his allies have championed the drug in broader debates about medical freedom and vaccine safety, as described in an investigation into NIH funding. That political backdrop makes it harder to separate scientific curiosity from ideological signaling, even if the bench scientists themselves are focused only on data.
Critics argue that taxpayer money should not be spent chasing what they see as a politically charged long shot when more promising cancer targets remain underfunded. Supporters counter that the sums involved in a small preclinical screen are modest compared with the overall NCI budget and that ruling out ivermectin with solid data could actually defuse misinformation. I think both sides underestimate how much the optics matter: in an era when trust in institutions is fragile, the mere fact that The National Cancer Institute is studying ivermectin’s ability to kill cancer cells, a development summarized in a Washington briefing on cancer research, will be read as validation by audiences primed to see conspiracies.
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*This article was researched with the help of AI, with human editors creating the final content.
