Ivermectin, Fenbendazole, Mebendazole, Niclosamide and Atovaquone for Cancer: Case Reports, Testimonials and Clinical Trials (2026)
Repurposed antiparasitic drugs in oncology
Search interest in ivermectin, fenbendazole, mebendazole, niclosamide and atovaquone for cancer has outpaced the clinical-trial record. This article compiles the two piles of information that usually get mixed together:
- Case reports and testimonials — published single-patient papers plus widely circulated self-reported stories
- Registered clinical trials — NCT numbers, phase, status and published results as of September 2026
None of these five medicines is approved by the FDA or EMA as a cancer treatment. That sentence is the most important line on this page.
Medical disclaimer. This is an evidence map for patients and clinicians, not a treatment protocol and not medical advice. Do not stop standard oncology care. High-dose veterinary products and unmonitored combinations have caused documented liver injury and, with ivermectin, life-threatening neurotoxicity. Discuss any off-label use with the oncologist who is reading your scans and labs.
On this page
1. How to read case reports vs clinical trials
| Source type | What it can show | What it cannot show |
|---|---|---|
| Social-media testimonial | Someone believes they improved | Causation, full concurrent treatment list, the patients who progressed |
| Peer-reviewed case report | A documented clinical course | That the same result will happen in the next 100 patients |
| Observational cohort / survey | Patterns people report | Independent radiology review; no control arm |
| Phase 0–I trial | Safety, dose, target engagement | Survival benefit |
| Phase II | A first efficacy signal | Practice-changing proof |
| Phase III | Whether the drug beats standard care | — |
Preclinical activity (cells and mice) exists for all five agents — microtubules, Wnt/β-catenin, STAT3, OXPHOS, mitochondrial uncoupling. Lab activity is not a human remission rate.
2. 2026 snapshot
| Drug | Human case-report density | Formal trial signal | Main safety issue in self-use |
|---|---|---|---|
| Ivermectin | High anecdotal; few peer-reviewed CRs | TNBC combo: 1 PR / 8 evaluable; one self-report cohort | High-dose neurotoxicity |
| Fenbendazole | Very high anecdotal | No human cancer RCT on ClinicalTrials.gov | Drug-induced liver injury |
| Mebendazole | Two classic published CRs | Glioma: feasible; GI Phase 2a negative; recurrent GBM missed OS target | Transaminitis at high mg/kg doses |
| Niclosamide | Almost none as monotherapy | Old oral form failed PK; reformulation + abiraterone: PSA responses | Poor absorption; GI toxicity |
| Atovaquone | Almost no “cure” stories | ATOM: hypoxia ↓ in NSCLC; ovarian and peds glioma trials open | Well tolerated at labeled dose |
3. Ivermectin
Published clinical material
- Infection-driven lymphoma (2026). Nongastric MALT lymphoma recurrence linked to duodenal Strongyloides achieved a complete PET response after oral ivermectin when systemic chemotherapy was deferred. That is treating a driver infection, not proof that ivermectin is a general anticancer drug.
- Parasite-indication safety review. Across 26 reports / 36 cancer patients given ivermectin for scabies, strongyloides or related infections, adverse events were mostly minor. That dataset does not measure tumor response.
- Hulscher et al., Anticancer Research 2026. Prospective telemedicine cohort: 197 patients prescribed compounded ivermectin 25 mg + mebendazole 250 mg; 122 completed 6-month surveys. Self-reported clinical benefit ratio 84.4%; 32.8% no evidence of disease, 15.6% regression, 36.1% stable, 15.6% progression. Concurrent chemotherapy 28%, radiation 21%, surgery 20%, supplements 49%. Outcomes are patient-reported, not centrally reviewed scans. The journal opened then later closed an ethics/IRB audit; treat the percentages as unverified.
- Harm case (2026). A 73-year-old woman with metastatic breast cancer self-administered high-dose ivermectin from online advice and developed altered mental status, seizures and respiratory failure requiring intubation. She recovered neurologically within 48 hours (Postgraduate Medicine).
Testimonials in circulation (not independently verified)
Compilations on X, Substack and long-form protocol blogs (including Makis-style case lists and colorectal series that now claim 80+ stories) follow a pattern: ivermectin often 0.5–1.5 mg/kg/day, frequently stacked with fenbendazole and/or mebendazole, often still on chemotherapy. Repeated examples include:
- 42-year-old woman, Netherlands, stage 4 rectal adenocarcinoma — IVM 1 mg/kg + FBZ 1776 mg + MBZ 1000 mg + chemo; reported ~25% shrinkage of lung nodules and rectal primary at 6 months
- 77-year-old California woman, stage 4 appendiceal neuroendocrine — no conventional oncology; reported 85% volume shrinkage (5.6 cm to 3.0 cm) at 3 months
- 53-year-old Pennsylvania man, stage 4 pancreatic — IVM 1.5 mg/kg + FBZ 1500 mg + chemo; reported PET NED, resolved liver metastases, CA19-9 154 → 17 at 6 months
- Emily Ziegler, age 36, pancreatic ductal carcinoma — ivermectin during a period of stalled growth, then chemo/radiation and later NED (standard therapy is central to the timeline)
- 67-year-old Minnesota woman, EGFR+ stage 4 NSCLC — IVM + FBZ + chemo; family reported SUV drops and resolution of pleural effusion
- 71-year-old Kansas woman, axillary breast-cancer recurrence — long-term then high-dose IVM + MBZ + letrozole; oncologist reportedly said ~90% of disease gone
These stories are Level 5 evidence. Many omit full concurrent drug lists. Survivors post; non-responders usually do not.
Registered ivermectin cancer trials
| ID | Design | Status (Sep 2026) | Result so far |
|---|---|---|---|
| NCT05318469 | Phase I/II. Ivermectin 30–60 mg days 1–3, 8–10, 15–17 of a 21-day cycle + balstilimab or pembrolizumab in metastatic TNBC (City of Hope / Cedars-Sinai) | Ongoing | ASCO 2025: 8 evaluable — 1 PR, 1 SD, 6 PD. Median PFS 2.5 months. 4-month CBR 37.5%. Combo described as safe. |
| NCT07487805 (ICONIC) | Phase 2. Intermediate- vs high-dose IVM added to ongoing checkpoint inhibitors in solid tumors (University of Florida), n≈80 | Not yet recruiting (est. start Sep 2026) | No data |
| NCT04447235 | IVM + losartan in cancer patients with COVID-19 | Terminated | COVID study, not an anticancer endpoint |
Florida funding, not a published RCT. The Florida Cancer Innovation Fund (~USD 60–70 million per cycle) lists generic-drug repurposing, including ivermectin, as a priority. That is a grant program. It is not the same thing as a completed Phase III oncology paper.
4. Fenbendazole
Fenbendazole is a veterinary benzimidazole. There is no completed human cancer randomized trial on ClinicalTrials.gov. Human benzimidazole oncology work uses mebendazole instead.
The index story: Joe Tippens
In 2016–2017 an Oklahoma businessman with widely metastatic small-cell lung cancer started Panacur C about 222 mg/day plus vitamin E, curcumin and CBD — while enrolled in a pembrolizumab (Keytruda) trial at MD Anderson. Subsequent PET scans showed no evidence of disease. He has said he was the only complete responder among roughly 1,100 trial patients; that claim is not independently confirmed. Concurrent immunotherapy is the main scientific confounder. The story launched the “Tippens protocol” and a self-medication wave in South Korea.
Published human material
- 2025 Case Reports in Oncology series of three self-treated patients (stage IV breast, prostate, melanoma; 222–444 mg/day plus other therapies, not chemotherapy): two complete remissions, one near-CR. The paper was later retracted for an undisclosed conflict of interest. Do not cite it as standing literature.
- Reviews mention a 2022 hepatocellular-carcinoma complete-remission case (Kim et al.); secondary sources are thin.
What is well documented: liver injury
- 80-year-old Japanese woman with NSCLC on pembrolizumab who self-started fenbendazole: ALT 487 U/L; resolved after stopping fenbendazole
- 67-year-old woman taking fenbendazole granules for a year for a precancerous skin lesion: jaundice, bilirubin to 24 mg/dL, biopsy-confirmed severe hepatocellular DILI; recovered after stopping
- 47-year-old woman with metastatic colon cancer on dual checkpoint blockade: severe hepatocellular injury after a fenbendazole dose increase; RUCAM score 8 (probable fenbendazole). Immunotherapy safely restarted after the drug was stopped
- Additional cholestatic/hepatocellular cases in patients with HCC/cirrhosis and in patients on cemiplimab
NCBI LiverTox now lists several clinically apparent DILI cases tied to off-label anticancer self-use of fenbendazole.
Testimonials
Hundreds circulate in Facebook groups and protocol blogs. Common recipe: 222–444 mg (sometimes 1–1.7 g) three to seven days per week, plus curcumin/CBD/vitamin E, often plus ivermectin. Tumor types span prostate, lung, colon, breast, pancreas and melanoma. Almost none include public source-document packages (full scan series, pathology, complete concurrent medication list).
5. Mebendazole
Mebendazole is the best-documented of the five in actual oncology journals. The signal is mixed: two striking older case reports, tolerable high-dose brain-tumor combinations, and a gastrointestinal monotherapy trial that failed.
Classic published case reports
- Dobrosotskaya et al., 2011 — metastatic adrenocortical carcinoma progressing after mitotane, chemotherapy and radiation. Mebendazole 100 mg twice daily as monotherapy: metastases initially regressed, then stable for 19 months; progressed at 24 months. Quality of life improved; toxicity was minimal.
- Nygren & Larsson, 2013/2014 — refractory metastatic colon cancer. Mebendazole 100 mg twice daily: at six weeks, near-complete remission of lung and nodal metastases and a good partial response in the liver. AST/ALT later rose 5–7× ULN; the dose was reduced. This remains the flagship drug-repositioning case.
Formal trials
| ID / study | Population | Result |
|---|---|---|
| NCT01729260 Johns Hopkins Phase 1 | Newly diagnosed high-grade glioma + adjuvant temozolomide, n=24, up to 200 mg/kg/day | Completed. Reversible grade 3 transaminitis at the top dose. Median OS 21 months (no control arm). |
| NCT02644291 pediatric recurrent brain tumors | Phase 1, up to 2500 mg/m²/day | Tolerable; limited single-agent activity (mean PFS about 7.6 weeks in the published pediatric series). |
| NCT01837862 + bev/irinotecan in pediatric/young-adult HGG | Phase 1 | MTD 200 mg/kg/day. ORR 33% (2 PR, 1 CR lasting 10 months). Mean PFS 4.7 months, OS 11.4 months from start of study drug. |
| NCT03628079 RepoMeb Repos Pharma | TDM-guided high-dose MBZ in refractory GI cancer / CUP, n=11 | Terminated for lack of effect. All who stayed on drug progressed by ~8 weeks; 4 met proposed hyperprogression criteria. Only 5/10 hit the 300 ng/mL serum target despite doses up to 4 g/day. |
| CTRI/2018/01/011542 India Phase 2 | Recurrent GBM: TMZ+MBZ vs CCNU+MBZ, n=88 | Missed the pre-set 9-month OS benchmark of 55% (36.6% and 45%). ECOG 0–1 subset on CCNU+MBZ: 57.9% — hypothesis-generating only. |
| NCT03925662 Tanta University | Labeled Phase 3 adjuvant MBZ + FOLFOX/bevacizumab in CRC, n≈40 | Listed recruiting since 2019; primary completion pushed to 2028. No public results. Treat as unverified until published. |
6. Niclosamide
Niclosamide hits Wnt, STAT3, Notch, mTOR and AR-V7 in models. In people the bottleneck is oral bioavailability.
- NCT02532114 (University of Washington): niclosamide three times daily + enzalutamide after abiraterone in mCRPC. Closed for futility. Could not escalate past 500 mg TID. Plasma 36–182 ng/mL, below the preclinical target. No PSA declines. GI dose-limiting toxicities (colitis, vomiting) at 1000 mg TID. Authors concluded standard oral niclosamide is not viable for CRPC.
- Phase Ib reformulation (PDMX1001) + abiraterone/prednisone (Parikh et al., Scientific Reports 2021), n=9: 5 of 8 evaluable patients had a ≥50% PSA drop; two reached undetectable PSA with radiographic improvement and remained on therapy more than three years at publication. One non-PSA-responder had a biopsied metastasis that was entirely necrotic. This is the strongest formal human signal — and it required a reformulation plus active hormone therapy.
- NCT02519582 NIKOLO (Charité): 2 g/day oral niclosamide in progressive metastatic CRC. Public status has been incomplete; no practice-changing publication.
- NCT02687009 (Duke): window-of-opportunity niclosamide before colon resection. Safety and Wnt pharmacodynamics.
- NCT05188170 (Stanford): niclosamide (ANA001) + cytarabine in pediatric relapsed/refractory AML. Recruiting; estimated primary completion September 2026.
- 2023 cocktail case: 41-year-old woman with platinum-resistant clear-cell ovarian cancer on metformin, simvastatin, niclosamide 2 g/day, mebendazole, itraconazole, loratadine and chloroquine. CA-125 304 → 54 and CA19-9 1210 → 386 over four months. Imaging mixed. Niclosamide cannot be isolated.
Standalone “I took niclosamide and the cancer vanished” threads are scarce compared with the ivermectin/fenbendazole archive.
7. Atovaquone
Atovaquone looks different from the dewormer-protocol internet. Almost no NED testimonials. The human data are mechanistic: OXPHOS inhibition, tumor hypoxia, STAT3.
- ATOM (NCT02628080), Oxford. Window-of-opportunity in resectable NSCLC. Fifteen patients received atovaquone 750 mg twice daily for about 12 days versus 15 untreated. Hypoxia PET: treated cohort median hypoxic volume −28% versus +15.5% untreated; adjusted hypoxic volume about 55% lower (p=0.004). Hypoxia and STAT3 gene signatures fell in resected tumors. No atovaquone-related adverse events. This shows hypoxia modification, not radiographic cure.
- Oxford follow-on: 750 mg twice daily was tolerable with radical chemoradiation in locally advanced NSCLC.
- NCT03568994 ATACC AML (Baylor): atovaquone at PJP-prophylaxis dosing plus standard induction in de novo pediatric/AYA AML, n=26. Completed; not yet a landmark efficacy paper.
- NCT05998135 (Emory/Winship): Phase 2 monotherapy in platinum-resistant ovarian cancer, n=28. Recruiting. Primary endpoint PFS; paired biopsies for STAT3 and immune infiltrate.
- NCT06624371 AflacBT2303 (Emory): Phase 1 atovaquone ± radiation in pediatric high-grade glioma, DMG/DIPG and medulloblastoma, n≈18. Recruiting (opened 2025). Rationale: radiosensitize hypoxic glioma.
- Retrospective AML / post-transplant series: longer atovaquone use for Pneumocystis prophylaxis associated with better relapse-free survival versus other prophylaxis. Confounded (who stays on atovaquone is not random).
8. Master list of registered oncology trials
| Drug | NCT / ID | Phase | Question | Status |
|---|---|---|---|---|
| Ivermectin | NCT05318469 | I/II | IVM + PD-1 in mTNBC | Ongoing; modest early signal |
| Ivermectin | NCT07487805 ICONIC | II | IVM + existing ICI, solid tumors | Not yet recruiting |
| Fenbendazole | — | — | Human cancer IND | None |
| Mebendazole | NCT01729260 | I | MBZ + TMZ, new HGG | Completed |
| Mebendazole | NCT02644291 | I | Pediatric recurrent brain tumors | Completed |
| Mebendazole | NCT01837862 | I/II | Pediatric glioma combinations | Results partly published |
| Mebendazole | NCT03628079 | 2a | High-dose MBZ, refractory GI | Terminated, no effect |
| Mebendazole | NCT03925662 | Listed III | Adjuvant CRC + FOLFOX/bev | Listed recruiting; no results |
| Mebendazole | CTRI/2018/01/011542 | II | Recurrent GBM | Missed OS benchmark |
| Niclosamide | NCT02532114 | I | + enzalutamide, mCRPC | Futility (PK) |
| Niclosamide | NCT03123978 | I | Reformulation + enzalutamide | Complete |
| Niclosamide | NCT02519582 NIKOLO | II | Metastatic CRC monotherapy | Incomplete public record |
| Niclosamide | NCT02687009 | I | Window before colon surgery | Complete / suspended listings |
| Niclosamide | NCT05188170 | I | + cytarabine, pediatric AML | Recruiting |
| Atovaquone | NCT02628080 ATOM | 0 | NSCLC hypoxia | Completed, positive on hypoxia |
| Atovaquone | NCT03568994 | Early I | + induction AML | Completed |
| Atovaquone | NCT05998135 | II | Platinum-resistant ovarian | Recruiting |
| Atovaquone | NCT06624371 | I | ± RT, pediatric glioma | Recruiting |
Verify live status on ClinicalTrials.gov before contacting a site. Enrollment runs through listed hospitals, not compounding telemedicine shops.
9. Safety signals that belong next to every testimonial
- Fenbendazole: hepatocellular and mixed DILI, including bilirubin 24 mg/dL and centrilobular necrosis on biopsy. Risk is higher with underlying liver disease and with checkpoint inhibitors (easy to mislabel as immune hepatitis).
- Ivermectin: CNS toxicity at very high doses — seizures, respiratory failure — especially if the blood–brain barrier is altered.
- Mebendazole: generally tolerated; high mg/kg doses cause reversible transaminitis. The GI monotherapy trial showed universal progression and possible hyperprogression in 4 of 10.
- Niclosamide: standard tablets often never reach target plasma levels; pushing the dose produces diarrhea, nausea and colitis.
- Atovaquone: best tolerated of the group at labeled doses. The live research question is radiosensitization and STAT3, not “replace chemo.”
ASCO’s May 2026 clinical notice cautioned against using ivermectin or fenbendazole to treat cancer outside a monitored clinical trial.
10. Why the Facebook archive and the NCT archive disagree
- The product is not the same. Trials use human-grade, PK-guided doses. Online protocols use veterinary granules, 1 mg/kg/day ivermectin and multi-gram fenbendazole — combinations that have never been the experimental arm of an RCT.
- Combinations hide the variable. Almost every circulating success story includes chemotherapy, immunotherapy, radiation, surgery or hormone therapy. Trials that isolated the antiparasitic (RepoMeb, UW niclosamide) were negative.
- Absorption. Mebendazole and niclosamide often never reach the concentrations that kill cells in a dish. That is why two formal studies died on pharmacokinetics, not on a conspiracy.
- Endpoints. ATOM succeeded on hypoxia PET. That is real and useful for radiation research. It is not the same as “cancer-free on a phone video.”
- Sponsorship. Off-patent drugs have weak commercial incentive. Florida’s innovation fund is one of the few public attempts to pay for that gap; it has not yet produced a published randomized oncology result for ivermectin.
- Selection bias. People who progress or die post less. People who improve on Keytruda plus fenbendazole credit the dewormer.
11. FAQ
Is there a Phase III trial proving any of these five drugs cure cancer?
No. As of September 2026 there is no completed Phase III of ivermectin, fenbendazole, mebendazole, niclosamide or atovaquone as cancer monotherapy that changed a label.
Which drug has the strongest human trial signal?
Depends on the question. Atovaquone has the cleanest mechanistic human result (NSCLC hypoxia). Reformulated niclosamide plus abiraterone has the clearest PSA/radiographic signal in a tiny CRPC cohort. Mebendazole has the most completed oncology protocols and they do not add up to a survival win. Ivermectin’s only registered efficacy peek is 1 partial response in 8 evaluable metastatic TNBC patients on a PD-1 antibody.
Which drug has the strongest testimonial archive?
Fenbendazole (Tippens protocol) and ivermectin-plus-benzimidazole stacks. Volume is not the same as verification.
Can I enroll in a fenbendazole cancer trial?
There isn’t one. The ethical, registered substitute is a mebendazole study — and several of those have already reported.
What should a patient who still wants to explore this actually do?
- Search the NCT numbers above and call the listed site
- Do not replace guideline therapy with veterinary paste
- If an oncologist agrees to supervise off-label human-grade mebendazole, ivermectin or atovaquone, insist on a baseline and follow-up liver panel, medication-interaction check and scheduled imaging — not only a Facebook before/after photo
Bottom line. Case reports and testimonials for these five antiparasitics are abundant and emotionally powerful. The registered trial record is small, early-phase and mixed: two older mebendazole remissions, one ivermectin-plus-PD-1 partial response, a niclosamide reformulation PSA signal, a clear atovaquone hypoxia effect, several negative or futile studies, and documented liver and neurologic harm from unsupervised self-dosing. That is the state of the evidence in September 2026 — not a hidden cure, and not “nothing to see.”
Related reading on this site: fenbendazole protocol overview, colorectal case compilations, and trial-watch updates. Always re-check ClinicalTrials.gov before citing a status.
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