What were the typical oral and intravenous ivermectin dosing regimens used in oncology clinical trials?
Executive summary
Clinical oncology trials and reports show oral ivermectin regimens in cancer studies most commonly as intermittent, multi-day courses within 21‑day cycles — for example oral ivermectin on days 1–3, 8–10 and 15–17 of each 21‑day cycle combined with checkpoint inhibitors — while reported high‑dose or off‑label oral use in anecdotal or non‑trial contexts ranges up to about 1–2 mg/kg/day (not trial‑standardized) [1] [2]. Published reviews and preclinical summaries say most human antiparasitic dosing is 150–400 µg/kg, some oncology translational work references higher experimental exposures (up to reported investigational uses of ~1.6–2 mg/kg in non‑cancer settings) and animal anticancer studies use much larger mg/kg equivalents, creating a gap between lab efficacy and clinically tested doses [3] [1] [4].
1. Trial protocols: intermittent oral ivermectin paired with immunotherapy
Recent oncology trial abstracts and trial registries document oral ivermectin given in short repeated bursts inside 21‑day cycles when combined with IV immune checkpoint antibodies. An ASCO‑reported phase I/II TNBC study and trial summaries describe ivermectin administered orally on days 1–3, 8–10 and 15–17 of each 21‑day cycle alongside IV balstilimab (450 mg) or pembrolizumab (200 mg) on day 1, with treatment planned for many cycles until progression or toxicity [1] [5]. ClinicalTrials.gov listings and news coverage cite these same schedules for ongoing combination trials [6] [7].
2. Intravenous ivermectin: scarce or absent in oncology trial reporting
Available sources do not describe standardized intravenous ivermectin regimens used in contemporary oncology trials. Trial abstracts and clinical‑trial summaries focus on oral dosing combined with IV immunotherapy agents, not IV ivermectin formulations [1] [5]. Historical or non‑oncology reports note parenteral ivermectin has been administered in some settings (subcutaneous up to 1.6 mg/kg twice weekly in a spinal‑injury study), but oncology trial registries and ASCO abstracts do not present routine IV ivermectin schedules for cancer patients [3].
3. Dose ranges: trial doses vs. preclinical and anecdotal higher dosing
The oncology combination trial uses a defined intermittent oral schedule rather than weight‑based continuous high dosing [1]. By contrast, reviews and case‑report aggregations note that antiparasitic human dosing is typically 150–400 µg/kg, while some experimental or anecdotal cancer protocols reported in non‑peer venues list much higher oral regimens — for example 1–2 mg/kg/day in community protocols — and preclinical anticancer animal studies often use very high mg/kg exposures that do not translate directly to human doses [3] [2] [8]. This divergence explains clinician skepticism: effective anticancer concentrations in mice may require exposures that would be toxic in humans [9].
4. Safety, efficacy signals and expert skepticism
Early phase results presented at ASCO reported limited activity: among a small cohort in the phase I/II TNBC study, outcomes included one partial response, one stable disease and progression in most evaluable patients, leading experts to conclude no clear benefit observed to date [5] [7] [9]. Reviews emphasize the absence of large randomized trials proving anticancer benefit and warn about self‑medication risks driven by social media; oncologists stress that doses effective in preclinical models may be toxic in humans [10] [9].
5. Why dosing varies: scientific rationale and practical constraints
Investigators testing ivermectin in oncology start with intermittent oral schedules combined with IV immunotherapies to explore synergy and tolerability while remaining within known safe exposure limits for humans [1] [4]. Preclinical pharmacology and animal efficacy studies use higher exposures that suggest potential mechanisms, but those exposures create an evidence gap: lab activity does not establish safe, effective human dosing [3]. Community or integrative protocols that report 1–2 mg/kg/day reflect an attempt to reach purportedly active concentrations but are not trial‑validated and carry safety and ethical concerns [2].
6. Bottom line for clinicians and patients
If you are a clinician or patient seeking specifics: trialized oral ivermectin regimens in cancer trials are being tested as intermittent multi‑day courses within 21‑day cycles alongside IV checkpoint inhibitors (e.g., days 1–3, 8–10, 15–17), while standardized IV ivermectin cancer regimens are not reported in current oncology trial materials [1] [5]. The literature and expert commentary caution that clinical benefit has not been proven in large trials and that preclinical dose‑effect findings do not straightforwardly justify high‑dose off‑label use [10] [9] [3].
Limitations: reporting is dominated by early‑phase abstracts, reviews and non‑randomized reports; full trial protocols and final peer‑reviewed phase II/III results are not yet available in the supplied sources [5] [6].