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What clinical trials have tested ivermectin as a cancer treatment in humans and what were their phases?
Executive Summary
The only clearly documented human clinical trial testing ivermectin specifically as a cancer therapy is a combined Phase I/II study (ClinicalTrials.gov identifier NCT05318469) that evaluates ivermectin in combination with the anti–PD‑1 antibody balstilimab in patients with metastatic triple‑negative breast cancer; this trial’s Phase I portion determines dosing and Phase II assesses efficacy (objective response, PFS, OS, clinical benefit) [1] [2]. Multiple reviews and preclinical papers describe promising anticancer mechanisms for ivermectin but note limited clinical evidence and no large-scale randomized trials confirming benefit in humans [3] [4] [5].
1. Why one human trial stands out and what it actually tests — the concrete evidence
Clinical-trial registries and oncology abstracts converge on a single, concrete human study that tests ivermectin in a cancer setting: a combined Phase I/II trial of ivermectin plus balstilimab for metastatic triple‑negative breast cancer. The trial’s Phase I portion is designed to determine a recommended Phase II dose and characterize safety; the Phase II expansion measures clinical endpoints such as objective response rate, progression‑free survival, overall survival, and clinical benefit rate, consistent with typical early‑phase oncology development [1] [2]. Trial registration and conference abstract listings are the sources reporting this design, and these documents frame ivermectin’s role as an adjunct immunotherapy sensitizer rather than a stand‑alone cytotoxic agent [1] [2]. Reports from 2024–2025 reiterate the trial’s existence and its focus on metastatic triple‑negative disease [1] [6] [7].
2. What reviewers and preclinical literature say — plausible biology but a big evidence gap
Multiple scientific reviews dating back to at least 2020 summarize preclinical evidence that ivermectin can inhibit cancer cell proliferation, reduce metastasis, reverse multidrug resistance, and modulate tumor‑relevant pathways, providing a biologic rationale for clinical testing [3] [5]. Those same reviews uniformly emphasize that clinical evidence in humans is sparse and that no large randomized controlled trials have established therapeutic benefit, framing current human work as exploratory and hypothesis‑generating rather than confirmatory [4] [3]. The literature therefore presents a classic translational arc—robust laboratory signals prompting early‑phase clinical evaluation, but insufficient clinical data to change practice [4] [5].
3. Where other sources diverge or fail to add trials — mixed signals and incomplete reporting
Some local or regional case reports and observational write‑ups mention ivermectin’s use or outcomes in cancer patients but do not document formal trial phases or controlled designs; these pieces do not identify additional registered Phase I, II, or III trials beyond NCT05318469 [8] [4]. Several syntheses note the absence of sizeable randomized trials and emphasize that human clinical evidence remains limited, underscoring a discrepancy between abundant preclinical interest and scarce clinical testing [4] [3]. The analyses show repeated statements that the only detailed human clinical study is the Phase I/II combination trial, with other reports either silent on human phases or focused on preclinical/observational experience [1] [8] [5].
4. How to interpret motivations and possible agendas in available sources
Sources include academic reviews, trial registries and advocacy summaries; reviewers caution clinicians to be circumspect because preclinical promise does not equate to clinical efficacy [4] [3]. Trial promoters and integrative‑care outlets emphasize exploratory potential and repurposing advantages (cost, safety profile in antiparasitic use), which can create optimism in public summaries; conversely, clinical reviewers and oncology abstracts stress the need for formal dose‑finding and efficacy endpoints before recommending use [6] [1] [2]. Recognize that advocacy pieces may accentuate positive implications of repurposing, while registries and oncology abstracts are focused on methodological rigor and endpoints [6] [2].
5. Bottom line for clinicians, patients and researchers — what the record shows and what’s next
The factual record extracted from recent analyses shows one registered Phase I/II human trial testing ivermectin in combination with an anti‑PD‑1 antibody for metastatic triple‑negative breast cancer; no Phase III or large randomized trials have been reported, and multiple reviews emphasize limited clinical evidence despite compelling preclinical data [1] [2] [4] [3]. For clinicians and patients this means ivermectin remains investigational in oncology and should be accessed only through formal trials; for researchers the clear gap is the need for rigorously controlled efficacy trials if early‑phase signals warrant further development [4] [1].