What clinical trials have tested ivermectin in combination with chemotherapy in cancer patients, and what were their outcomes?

1. Trials actually registered and described

The clearest, repeatedly cited clinical record is a phase I/II investigator-initiated study (ClinicalTrials.gov identifier NCT05318469) testing oral ivermectin together with the anti–PD-1 agent balstilimab — and in some descriptions pembrolizumab as an alternative — in patients with metastatic triple-negative breast cancer (mTNBC) ^{[1] [6]}. This trial has been reported in an ASCO abstract and on institutional/trial pages and is framed as a safety/tolerability and early-efficacy study rather than a randomized test against standard chemotherapy ^{[1] [6]}. Apart from this immunotherapy combination, reviewers and clinical overviews consistently report that human clinical trials of ivermectin in oncology are scarce and that no large-scale randomized controlled trials (RCTs) demonstrate benefit of ivermectin for cancer ^{[7] [3]}.

2. Published clinical outcomes: what exists (and what does not)

There are no peer‑reviewed, published Phase III or large Phase II trials showing that ivermectin plus chemotherapy improves survival or response in cancer patients in the sources provided; the active clinical work noted is early-phase and, as of these reports, without published definitive outcome data ^{[3] [7] [2]}. Reviews that aggregate clinical experience emphasize a paucity of human trial data and note that most evidence of benefit comes from laboratory and animal studies rather than controlled human trials ^{[4] [7]}. Some observational reports and reviews suggest ivermectin was generally tolerated in small, non‑oncology contexts or when used by cancer patients for parasitic indications, but these are not controlled efficacy data for anticancer combinations ^[8].

3. Why researchers pursued combinations with chemotherapy or immunotherapy

Mechanistic and preclinical literature shows ivermectin can induce apoptosis, autophagy, mitochondrial dysfunction, inhibit tumor stem cells and reverse multidrug resistance, and in cell and animal models has synergized with drugs such as docetaxel, gemcitabine and paclitaxel — providing the biological rationale to test combinations with cytotoxics or checkpoint inhibitors ^{[4] [5] [9]}. Several in vitro and animal studies report that ivermectin can resensitize drug‑resistant cancer cells and inhibit efflux pumps like P‑gp/ABCB1, which motivates translational trials despite uncertainty about achievable plasma concentrations in humans ^{[5] [4]}.

4. Safety signals, clinical caution and the gap from bench to bedside

Authors and oncology commentators repeatedly warn that preclinical potency does not equal clinical benefit and that the absence of large RCTs means efficacy in humans is unproven; moreover, clinicians report worrying cases where patients self‑medicated with ivermectin and experienced toxicity or delayed standard therapy, underscoring ethical and safety concerns ^{[3] [2]}. Past experience with P‑gp inhibitors in cancer shows that inhibiting drug efflux can increase chemotherapy toxicity systemically, a mechanistic caution highlighted in the literature and relevant to ivermectin combinations ^[5].

5. Bottom line for evidence on combinations with chemotherapy

No completed clinical trials in the reviewed sources demonstrate that ivermectin combined with conventional chemotherapy improves outcomes in cancer patients; the only clearly documented human trial activity involves ivermectin combined with immune checkpoint inhibitors in an early-phase mTNBC study (NCT05318469), and published clinical outcomes from that program are not reported in these sources ^{[1] [6] [2]}. The scientific case rests on promising preclinical synergy, but rigorous clinical validation—especially randomized trials assessing both efficacy and safety—has not yet occurred ^{[4] [7]}.