What cancer types were targeted in clinical trials using ivermectin and what were the dosing regimens?
Executive summary
Clinical testing of ivermectin in human cancer patients is very limited and primarily focuses on combinations with immune checkpoint inhibitors in metastatic triple‑negative breast cancer (mTNBC); one registered Phase I/II trial (NCT05318469) tests oral ivermectin given intermittently with balstilimab/pembrolizumab in mTNBC (trial record and meeting abstract) [1] [2]. Most other evidence for anticancer activity remains preclinical—cell lines and animal models across many tumor types—and reviews note a scarcity of human trials [3] [4] [5].
1. What trials exist: a narrow clinical footprint, mostly one registered study
Only a small number of clinical entries and meeting abstracts report ivermectin in oncology; the clearest human trial is a Phase I/II study of ivermectin combined with the anti‑PD‑1 agent balstilimab (with pembrolizumab referenced) for metastatic triple‑negative breast cancer, registered as NCT05318469 and summarized in an ASCO abstract and ClinicalTrials.gov record [2] [1] [6]. Public summaries and charity trial pages list that trial as the primary human test of ivermectin in cancer to date [7].
2. Which cancer types were targeted: primarily triple‑negative breast cancer
The registered and reported human study targets metastatic triple‑negative breast cancer (mTNBC) with an expansion cohort for PD‑L1–negative disease (NCT05318469) [7] [2]. Other sources and reviews catalogue preclinical activity across many cancers—breast, pancreatic, colorectal, glioblastoma and more—but these are laboratory or animal studies rather than clinical trials [3] [8] [9] [5].
3. Dosing regimens reported in human trials: intermittent oral ivermectin during 21‑day cycles
Public trial descriptions and secondary reporting state the investigational regimen uses oral ivermectin given on Days 1–3, 8–10 and 15–17 of each 21‑day cycle, combined with an immune checkpoint inhibitor (balstilimab 450 mg IV or pembrolizumab 200 mg IV on Day 1) for up to roughly two years (up to 35 cycles) [10] [11]. ClinicalTrials.gov entries and the ASCO abstract (NCT05318469) are the primary records for this protocol [1] [2].
4. How solid is the human evidence: still exploratory and small
Reviews and recent literature emphasize that clinical evidence is scarce; most positive signals derive from cell lines and animal models and small early‑phase efforts rather than randomized trials. A 2025 review warns there are no large RCTs confirming benefit and stresses ethical concerns if patients forgo proven therapies based on limited data [4] [3] [5]. One 2025 article summarizes ongoing U.S. trials but reiterates the need for rigorous phase‑3 testing if early results appear promising [11].
5. Mechanistic and preclinical context: why investigators took ivermectin into trials
Laboratory studies show ivermectin can inhibit proliferation, induce apoptosis and modulate pathways such as Wnt/β‑catenin and others; it also appears to enhance tumor immune infiltration in preclinical breast‑cancer models, which motivated tests with checkpoint inhibitors [9] [3] [7]. Synergy with other agents (for example, recombinant methioninase in pancreatic cell lines) has been reported in vitro, but such combinations remain at the preclinical stage [8] [12].
6. Conflicting views, safety and practical concerns
Sources note divergent perspectives: proponents point to multi‑targeted anticancer effects in preclinical work and the drug’s known safety at antiparasitic doses, while cautious clinicians and reviews highlight the lack of clinical proof, potential for toxicity when used off‑label, and ethical risks of patients abandoning standard cancer care [4] [11] [5]. Reports of clinician frustration and anecdotal toxicity cases underline real‑world concerns pending trial results [11].
7. Limits of current reporting and what’s not found
Available sources document the mTNBC trial and preclinical breadth but do not provide complete published phase‑trial results, long‑term safety outcomes in cancer patients, or large randomized data proving efficacy; detailed pharmacokinetics at the oncologic doses used and outcomes from NCT05318469 beyond abstracts are not found in the provided reporting [2] [1] [4]. Broader claims that ivermectin is an effective cancer treatment are not supported by the cited clinical evidence [3] [5].
Conclusion: Human testing of ivermectin in cancer is currently limited to early‑phase, investigator‑led efforts—most notably a Phase I/II combination trial in metastatic triple‑negative breast cancer using intermittent oral ivermectin during 21‑day cycles with a PD‑1 inhibitor—while the bulk of supportive data remains preclinical and requires rigorous clinical validation [2] [10] [4].