Does ivermectin treat cancer?

As of March 2026, there is no clinical evidence that ivermectin treats cancer in humans. Preclinical studies show impressive anticancer activity across multiple pathways (PAK1, Wnt/β-catenin, Akt/mTOR), and the first Phase I/II human trial (NCT05318469) is underway at Cedars-Sinai combining ivermectin with immunotherapy in triple-negative breast cancer. However, a key challenge is whether anticancer concentrations can be safely achieved in humans with oral dosing.

What is the ivermectin cancer mechanism?

Ivermectin affects multiple cancer pathways simultaneously: it inhibits PAK1 kinase (a master regulator of cancer cell proliferation), blocks Wnt/β-catenin signaling, suppresses Akt/mTOR pathway, induces immunogenic cell death (converting 'cold' tumors 'hot'), and triggers mitochondrial dysfunction. This multi-target approach is why it shows broad preclinical activity, but also why effective dosing is complex.

Is ivermectin safe for cancer patients?

Ivermectin is FDA-approved for parasitic infections at doses of 150-200 mcg/kg. At these standard doses, it has an excellent safety profile. However, the anticancer concentrations seen in preclinical studies (5-20 μM) may require doses significantly higher than the approved antiparasitic dose. The safety of high-dose ivermectin in cancer patients is being evaluated in the ongoing Cedars-Sinai trial (30-60mg daily dosing). Self-dosing at high levels without medical supervision is not recommended.

What cancers has ivermectin been studied for?

In preclinical (cell and animal) studies, ivermectin has shown activity against breast cancer (especially triple-negative), colorectal cancer, ovarian cancer, pancreatic cancer, lung cancer, glioblastoma, leukemia, and melanoma. The only active human clinical trial is in metastatic triple-negative breast cancer (NCT05318469), combining ivermectin with checkpoint immunotherapy.

Ivermectin for Cancer: Multi-Target Mechanism, Trial Data, and the Dose Problem

The Bottom Line

Ivermectin is an FDA-approved antiparasitic drug (Nobel Prize in Medicine, 2015) with one of the most impressive preclinical anticancer profiles of any repurposed compound. It hits multiple cancer pathways simultaneously: PAK1 kinase inhibition, Wnt/β-catenin suppression, Akt/mTOR blockade, immunogenic cell death induction, and mitochondrial dysfunction. Published data spans breast, colorectal, ovarian, pancreatic, lung, and brain cancers.

But here's the critical gap: as of March 2026, there are no completed human clinical trials of ivermectin for cancer. A September 2025 review in Annals of Oncology stated flatly: "there is no clinical evidence in humans supporting the role of this anti-parasitic drug in cancer." The first Phase I/II trial (NCT05318469) combining ivermectin with checkpoint immunotherapy in triple-negative breast cancer is underway at Cedars-Sinai, and early ASCO 2025 data was presented. Results are pending.

The central challenge is pharmacokinetic: the anticancer concentrations seen in cell studies (5-20 μM) may be difficult to achieve safely with oral dosing in humans. This is the dose problem that separates "works in a dish" from "works in a person."

What It Is

Ivermectin is an avermectin derivative discovered in 1975 and approved for human use in 1987. It earned Satoshi Omura and William Campbell the 2015 Nobel Prize in Physiology or Medicine for its role in treating river blindness and lymphatic filariasis. It is on the WHO's List of Essential Medicines and has been administered to hundreds of millions of people globally for parasitic infections.

The standard antiparasitic dose is 150-200 mcg/kg (roughly 12-18mg for an average adult), given as a single dose or short course. At this dose, it has an excellent safety profile established over decades.

How It Works Against Cancer (Multi-Target Mechanism)

What makes ivermectin unusual among repurposed drug candidates is the sheer number of cancer pathways it affects. This isn't a single-mechanism drug:

PAK1 kinase inhibition: This may be the central mechanism. P21-activated kinase 1 (PAK1) is a master regulator of cancer cell proliferation, survival, and metastasis. Ivermectin degrades PAK1 via the ubiquitination pathway. A 2020 review in Pharmacological Research concluded that "IVM inhibits tumor cell development in a PAK1-dependent manner in most cancers." PAK1 is overexpressed in breast, colorectal, lung, pancreatic, and ovarian cancers.
Wnt/β-catenin pathway suppression: Ivermectin blocks WNT-TCF signaling, a pathway that drives cancer stem cell self-renewal and resistance to therapy. A 2025 PLOS One study showed ivermectin inhibits epithelial-to-mesenchymal transition (EMT) via Wnt signaling in endocrine-resistant breast cancer cells.
Akt/mTOR pathway blockade: Suppresses the PI3K/Akt/mTOR signaling cascade that cancer cells use to grow and resist apoptosis. Demonstrated in ovarian cancer and hepatocellular carcinoma models.
Immunogenic cell death (ICD): This is the most exciting recent finding. Ivermectin induces a form of cancer cell death that alerts the immune system, effectively converting "cold" tumors (invisible to immune cells) into "hot" tumors (infiltrated by T-cells). A 2021 PMC study showed "bona fide synergistic activity" when combined with checkpoint immunotherapy in breast cancer mouse models (p < 0.001). This is the rationale behind the Cedars-Sinai trial.
Mitochondrial dysfunction: Disrupts cancer cell energy metabolism through mitochondrial membrane depolarization.
Nuclear transport inhibition: Blocks importin α/β-mediated nuclear transport, preventing cancer cells from shuttling survival signals to the nucleus.
Anti-angiogenic: Inhibits new blood vessel formation at pharmacological concentrations.

Preclinical Data by Cancer Type

Triple-negative breast cancer (TNBC): The strongest preclinical case. Ivermectin induces ICD, blocks PAK1/Akt, and synergizes with checkpoint inhibitors. The Cedars-Sinai trial specifically targets TNBC because of this data.
Colorectal cancer: WNT/β-catenin pathway is frequently mutated in CRC. Ivermectin's WNT suppression makes it mechanistically relevant.
Ovarian cancer: Akt/mTOR inhibition demonstrated in ovarian cancer cell lines.
Pancreatic cancer: Synergistic activity with recombinant methioninase (rMETase) in MiaPaCa-2 cells (Anticancer Research, Jan 2025).
Lung cancer: PAK1-dependent growth inhibition demonstrated in lung adenocarcinoma.
Glioblastoma: In vitro activity, but blood-brain barrier penetration at therapeutic levels is uncertain.
Leukemia/lymphoma: Activity against AML cells through mitochondrial mechanisms.

The Dose Problem (Why Lab Results May Not Translate)

This is the elephant in the room that most ivermectin-cancer advocates don't address honestly.

In cell studies, anticancer effects are typically seen at ivermectin concentrations of 5-20 μM. At the standard antiparasitic dose (150-200 mcg/kg), peak plasma concentration in humans is approximately 0.05-0.1 μM. That's roughly 50-400x lower than the concentrations that kill cancer cells in a dish.

This doesn't mean ivermectin can't work in humans. Several factors may partially close this gap:

Tissue accumulation: Ivermectin is highly lipophilic and accumulates in fatty tissues at concentrations higher than plasma levels
Sustained exposure: Daily dosing (as in the Cedars-Sinai trial: 30-60mg daily) may achieve higher steady-state levels than single-dose antiparasitic use
Immune mechanism: The ICD/immunotherapy synergy may work at lower concentrations than direct cytotoxicity requires
Combination effects: Synergy with other drugs may reduce the effective concentration needed

The Cedars-Sinai trial (NCT05318469) is specifically designed to answer this question. It's testing escalating doses of 30mg, 45mg, and 60mg daily (roughly 2-4x the standard antiparasitic dose) in combination with immunotherapy. Until this trial reports, the dose question remains genuinely unresolved.

Human Clinical Evidence

The Cedars-Sinai Trial (NCT05318469)

This is the first rigorous human clinical trial of ivermectin for cancer:

Design: Phase I/II, dose-escalation + expansion cohort
Population: Metastatic triple-negative breast cancer, progressed on 1-2 prior therapies including immunotherapy
Treatment: Ivermectin (30/45/60mg daily, days 1-3, 8-10, 15-17 of 21-day cycles) + balstilimab (anti-PD-1 checkpoint inhibitor)
PI: Yuan Yuan, MD, PhD (Cedars-Sinai Medical Center)
Rationale: Ivermectin's ICD mechanism converts cold tumors hot, potentially re-sensitizing immunotherapy-resistant cancers
Status: Active. ASCO 2025 abstract (e13146) presented preliminary data. Full results pending.

Separately, there's a parallel trial arm using pembrolizumab (Keytruda) instead of balstilimab.

The Annals of Oncology review (Sept 2025) confirmed this is the only active clinical trial evaluating ivermectin in cancer as of that date.

Case Reports and Anecdotal Evidence

Dr. William Makis (McGill Medicine) has reported treating thousands of cancer patients with high-dose ivermectin protocols and claims remarkable results. However, these are uncontrolled case series without peer-reviewed publication in major journals. While his clinical experience is noted by the repurposed drug community, anecdotal data cannot establish efficacy or rule out confounders. Clinical trials exist specifically because individual cases, even many of them, cannot prove causation.

Safety Profile

At standard antiparasitic doses (150-200 mcg/kg), ivermectin has an excellent safety profile established over billions of doses worldwide. Common side effects are mild: dizziness, nausea, diarrhea, and itching (often from parasite die-off, not the drug itself).

At the higher doses being tested for cancer (30-60mg daily):

Safety data is being generated by the Cedars-Sinai trial
Neurotoxicity is a theoretical concern at very high doses (ivermectin is a GABA agonist)
P-glycoprotein (P-gp) deficiency increases ivermectin brain penetration and toxicity risk (this is why certain dog breeds are sensitive to ivermectin)
Drug interactions: caution with CYP3A4 inhibitors (ketoconazole, itraconazole, clarithromycin) which increase ivermectin levels
Unlike fenbendazole, ivermectin has extensive human pharmacokinetic data at standard doses

The COVID Controversy and Cancer Research

Ivermectin became deeply politicized during COVID-19, and this has both helped and hurt the cancer research community. The heightened awareness brought attention to ivermectin's anticancer properties, but the polarization made serious researchers reluctant to study it and made it harder to get unbiased media coverage of legitimate cancer research.

The cancer mechanism of ivermectin is completely unrelated to any antiviral mechanism. The PAK1 inhibition, ICD induction, and Wnt pathway effects are well-characterized and published in mainstream oncology journals. The cancer research predates the COVID debate by years.

Ivermectin vs. Other Repurposed Drugs

Drug	Human Trials	Key Advantage	Our Grade
High-Dose IV Vitamin C	Phase II RCT (pancreatic)	Doubled survival in one of the deadliest cancers	Grade A
Mebendazole	Phase I GBM, Phase 2a GI, RCT CRC	FDA-approved for humans, BBB penetration	Grade B
Ivermectin	Phase I/II underway (TNBC)	Multi-target, ICD induction, immunotherapy synergy	Grade C
Fenbendazole	Zero	Glycolysis inhibition (preclinical only)	Grade C

Our Assessment

Ivermectin has one of the most compelling preclinical anticancer profiles of any repurposed drug. The multi-pathway mechanism, the immunogenic cell death data, and the synergy with checkpoint immunotherapy are genuinely exciting. The fact that a serious Phase I/II trial is underway at a top institution (Cedars-Sinai) validates the scientific rationale.

But preclinical excitement doesn't equal clinical proof. The dose problem is real and unresolved. The Annals of Oncology 2025 review is correct that there is currently no clinical evidence supporting ivermectin for cancer in humans. The Cedars-Sinai trial may change this, or it may not. That's what trials are for.

Where ivermectin stands out: The ICD mechanism is unique among repurposed drugs. If ivermectin can reliably convert cold tumors hot and re-sensitize patients to immunotherapy, that would be transformative for cancers that currently resist checkpoint inhibitors. This is a mechanism that warrants rigorous investigation.

Our recommendation: Watch the Cedars-Sinai trial results closely. Do not self-dose high-dose ivermectin for cancer without medical supervision. If you're interested in repurposed drugs with existing human evidence, high-dose IV vitamin C (Grade A) and mebendazole (Grade B) have stronger clinical data today.

Sources

PMC7505114 (2020): "Ivermectin, a potential anticancer drug derived from an antiparasitic drug" (comprehensive mechanism review) pmc.ncbi.nlm.nih.gov
PMC7925581 (2021): "Ivermectin converts cold tumors hot and synergizes with immune checkpoint blockade" (breast cancer ICD study) pmc.ncbi.nlm.nih.gov
Pharmaceuticals 2025;18(10):1459: "Ivermectin as an Alternative Anticancer Agent" (multi-pathway review) mdpi.com
PubMed 40715995 (2025): "Ivermectin in Cancer Treatment: Should Healthcare Providers Caution or Explore?" pubmed.ncbi.nlm.nih.gov
PLOS One 2025: Ivermectin inhibits EMT via Wnt signaling in endocrine-resistant breast cancer journals.plos.org
Annals of Oncology 2025;36(suppl):2833P: "Ivermectin in cancer, 2025" annalsofoncology.org
JCO 2025;43(16_suppl):e13146: Cedars-Sinai Phase I/II ivermectin + balstilimab ASCO abstract ascopubs.org
ClinicalTrials.gov NCT05318469: Ivermectin + checkpoint inhibitor in metastatic TNBC clinicaltrials.gov
Anticancer Research 2025;45(1):97-103: Ivermectin + rMETase synergy in pancreatic cancer ar.iiarjournals.org
Cancer Research 2024;84(9_Suppl):PO1-19-07: AACR Phase I study abstract aacrjournals.org

Ivermectin for Cancer: Multi-Target Mechanism, the First Human Trial, and the Dose Problem