Real-world clinical outcomes of ivermectin and mebendazole in cancer patients: results from a prospective observational cohort (with 2026 expression of concern)
A telemedicine company's survey of patients it prescribed ivermectin and mebendazole reported that most felt better; the journal has attached an expression of concern while it checks whether the diagnoses, the regressions and the ethical approval can be verified.
Overview
The cohort comprised 197 patients with cancer prescribed compounded ivermectin 25 mg with mebendazole 250 mg off-label through a US telemedicine platform, of whom 122 completed a six-month digital survey; the authors report a self-assessed 'clinical benefit ratio' of 84.4 percent, with 48.4 percent reporting regression or no evidence of disease, 36.1 percent stable and 15.6 percent progression, side effects in 25.4 percent, and 27.9 percent also on chemotherapy (Hulscher cohort 2026). On 9 June 2026 the journal's editorial board issued an expression of concern citing serious concerns about the verifiability, statistical reliability and ethical oversight of the dataset, and opened an audit of the institutional review board documentation, the source records confirming the 197 baseline diagnoses and the medical documentation behind the reported regressions (Anticancer Research expression of concern 2026). The board also stated that it does not endorse or condone unvalidated off-label use of medications for unapproved oncological indications (Anticancer Research expression of concern 2026).
- 197 prescribed, 122 surveyed at six months; outcomes were self-reported by the patients, not measured by scans read for the study.
- Expression of concern, 9 June 2026: audit of ethical approval, baseline diagnoses and the documentation behind reported regressions.
This is the paper most often quoted online as proof. Patients reporting how they feel to the company that sold them the treatment, with 38 percent not answering, cannot show whether a cancer shrank, and the journal is now checking whether the underlying records exist.
- Self-reported outcomes through digital surveys; no independent imaging review; 38 percent lost to follow-up.
- Expression of concern issued 9 June 2026; a further update notice is indexed on Europe PMC (PMID 42703869, September 2026) whose content OnCo has not read.
- Many participants were also receiving chemotherapy, radiotherapy or surgery.
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