Evidence Explorer / MS-N109
UNSUPPORTED CURE CLAIMS & INVESTIGATIONAL DRUG REPURPOSING
Ivermectin as a cancer treatment: what human evidence shows
Evidence label: Preclinical rationale; inadequate human efficacy evidence; meaningful toxicity risk · Clinical goal: assess claims that ivermectin controls cancer
Evidence at a glance
- Laboratory and animal experiments report anticancer mechanisms in several models, but those findings cannot establish a safe or effective cancer treatment in people.
- The only prospectively reported cancer experience located was a small phase I/II combination study in metastatic triple-negative breast cancer: nine people enrolled, eight were evaluable, and the meeting abstract reported one partial response, one stable disease and six progressions. Ivermectin’s contribution cannot be separated from checkpoint immunotherapy.
- The official NCI record for NCT05318469 now says withdrawn. No actively recruiting anticancer ivermectin trial was verified in this search. A circulated “ICONIC” identifier, NCT07487805, could not be confirmed in ClinicalTrials.gov and is not treated as a real trial here.
- A 197-person retrospective ivermectin-plus-mebendazole report has been retracted. High-dose self-administration has also caused life-threatening neurotoxicity and has been implicated in severe liver injury.
What human evidence exists?
A 2025 ASCO meeting abstract described ivermectin given on days 1–3, 8–10 and 15–17 of a 21-day cycle with the PD-1 antibody balstilimab in metastatic triple-negative breast cancer. Doses escalated from 30 to 60 mg daily. Of eight evaluable participants, one had a partial response and one had stable disease; the median progression-free survival reported in the abstract was 2.5 months. With no ivermectin-only arm, an extremely small sample and abstract-only reporting, this cannot show whether ivermectin added benefit.
A retrospective series claiming outcomes for 197 patients treated with ivermectin plus mebendazole was published in 2025 and subsequently retracted. Its efficacy claims should not be used. Retraction is a material reversal, not merely a limitation.
NCT02366884 studied a multiagent “repositioned drugs” regimen in glioblastoma. Its registry status and multi-drug design do not provide evidence that ivermectin itself controls cancer. Registration is not proof of benefit.
What preclinical work suggests—and cannot establish
Cell and animal studies have reported effects on WNT/β-catenin signaling, PAK1, mitochondrial function, autophagy and drug sensitivity in models including leukemia, ovarian, breast, gastrointestinal and pancreatic cancers. Concentrations, exposures and model conditions vary, and laboratory activity does not tell us that a tolerable human dose reaches tumors or improves survival.
Preclinical plausibility is a reason to design careful trials. It is not a reason to replace surgery, radiation, endocrine therapy, immunotherapy or systemic anticancer treatment.
Safety and practical context
Ivermectin is an approved antiparasitic drug for specific human infections, not an approved cancer treatment. Veterinary products can have different concentrations and excipients. A 2026 case report described altered mental status, seizures, respiratory failure and intubation after high-dose self-administration by a person with metastatic breast cancer. Severe drug-induced liver injury has also been reported after combined veterinary anthelmintic use.
Potential concerns include neurologic toxicity, liver injury, dosing errors and interactions through drug transporters or metabolism. Illness, low body weight, hepatic impairment and concurrent cancer therapy can change risk. Do not use internet dosing schedules or veterinary formulations.
Bottom line
There is no reliable human evidence that ivermectin alone shrinks tumors, delays recurrence or improves survival. The preliminary combination abstract is hypothesis-generating only, and the relevant registered study is withdrawn. ASCO has cautioned against ivermectin or fenbendazole as cancer treatments outside clinical trials.
Questions for the care team
- What established treatments would be delayed, reduced or complicated by trying this drug?
- Has the exact product and dose been reviewed by oncology and pharmacy for interactions and liver or neurologic risk?
- If a trial is being proposed, is it listed in an authoritative registry with a real site contact and clear oversight?
Sources
- Narrative review of ivermectin in oncology (PMID 40715995)
- 2025 ASCO meeting abstract: ivermectin plus balstilimab
- NCI trial record NCT05318469 — withdrawn
- Life-threatening ivermectin neurotoxicity case (PMID 42170801)
- Severe liver injury after veterinary anthelmintic co-use (PMID 42299164)
- Retracted ivermectin–mebendazole cohort (PMID 42203321)
- Retraction notice (PMID 42823188)
- ASCO clinical notice on ivermectin and fenbendazole (May 2026)
Literature searched: October 23, 2026 · Record appraised: October 23, 2026
Educational evidence summary, not personal medical advice. Research regimens describe what was studied; they are not personal prescribing instructions and should not replace cancer treatment or individualized supportive care.
