In May 2026, I wrote my impressions of an unpublished study released by The Wellness Company (TWC). TWC sells supplements as well as various on-label and off-label prescription medications through their telehealth providers. The Chief Scientific Officer is Peter McCullough, MD, MPH. You may recall Dr. McCullough as a highly published cardiologist turned hydroxychloroquine evangelist, turned ivermectin evangelist, turned COVID contrarian.
The authors touted the study as supportive of the utility of ivermectin and mebendazole in the treatment of cancer. Ivermectin and mebendazole are anti-parasitic medications sold as a compounded combination by TWC. These drugs have demonstrated some anticancer activity in preclinical studies, but there are no good studies supporting their use for the treatment of cancer in humans.
The paper has 12 authors, all of whom are affiliated with and/or salaried by TWC. Conflicts of interest are appropriately disclosed in the paper.
The TWC study had fatal methodological weaknesses, rendering the data impotent to support assertions the authors (and others) were making on social media. There were also some problematic ethical issues regarding the oversight of the study and adequate protection of the study subjects. At the time, the study had not been published in a peer-reviewed journal, but was displayed prominently on the TWC website and circulated widely on social media.
Methodological Madness
Briefly, subjects in this study were Wellness Company telehealth patients. Patients reported a diagnosis of cancer, and were prescribed a combination of ivermectin and mebendazole by a Wellness Company telehealth provider. Patients were invited to fill out online surveys including demographic information and the type and status of their cancer, at baseline and again at 6 months. I pointed out multiple methodological weaknesses in the study rendering the results worthless in assessing the effects of these 2 repurposed drugs on cancer, including:
- Completely patient-reported data. Generally, clinical trials in cancer depend on structured, pre-specified, meticulously verified data. None of the investigators in this study examined the patients, ordered or reviewed scans or lab tests. It is not even noted that investigators independently reviewed medical records. All of the information about the type of cancer, prior treatment, ongoing treatments, health status, and status of cancer were provided by the patient. The article says these were “confirmed cancer diagnoses.” It is unclear what is meant by “confirmed” given these are exclusively patient-reported data.
- No control group. Patients in this study had over a dozen types of cancer. Most of the patients had received or were currently receiving conventional therapy such as surgery, chemotherapy, radiation therapy, etc. The majority of patients reported that their cancer was “not spreading” at baseline. To determine whether or not ivermectin and mebendazole had any influence on the cancer 6 months later, we would need to compare to a similar control group that was not receiving ivermectin and mebendazole.
- Dropouts. 38% of the baseline subjects did not fill out a survey at 6 months. We have no idea how many of these patients had worsening of their cancer, how many had intolerable side effects, and how many died. Attrition of over 1/3 of patients in 6 months is a serious limitation and an enormous red flag.
Based on these weaknesses, it is impossible to determine if ivermectin and mebendazole individually or collectively are helpful, harmful, or indifferent in treatment of cancer.
Ethical ambiguity
There are standards for the ethical conduct of research involving human subjects. The Declaration of Helsinki is a foundational document in enumerating these ethical principles. The Declaration was first adopted in 1964, but it is a living document, with the latest revision in 2024. Although the specific regulatory frameworks vary from country to country, they are largely harmonized under principles expressed in the Declaration of Helsinki.
The role of the Institutional Review Board
In the US, Institutional Review Boards (IRBs) are the bodies that assess and regulate human research on a study-by-study basis. IRBs operate under the “Common Rule” or 45 CFR 46. The Common Rule explicitly applies to research funded by the US government, but other factors can trigger the application of the Common Rule. Research done under the jurisdiction of the FDA is regulated under the Common Rule, as well as other regulatory standards. Private funders usually want to ensure that their grants are used to fund ethical research. Scientific journals usually have standards for the ethical conduct of research they publish, including IRB review.
Even research that involves only surveys or questionnaires may be under the jurisdiction of an IRB. For projects of this type, questions addressed by IRBs include:
- Was subject participation truly voluntary?
- Were subjects informed that the data they provide was going to be used for research?
- Were subjects informed of risks of participation, including loss of privacy?
- Was informed consent obtained and properly documented?
- Were subjects able to withdraw from the study, and were they informed of such?
- Was personal health information protected?
In the report posted on their website, TWC authors made the case that the nature of this study was not human research. TWC authors were explicit in characterizing their study as “quality improvement,” therefore not human research, and not subject to oversight by an IRB. Quality improvement is, indeed, a category of study that is usually (but not always) exempt from IRB review. For reasons I articulated in detail in my previous report, the assertion by TWC authors that their study was quality improvement was, in my opinion, specious and self-serving.
If I had a car but wanted to drive it without a license and without regard for the rules of the road, I could simply declare my vehicle a go-kart. Go-karts are vehicles that actually exist, but they are not subject to the same laws as cars. Calling my car a go-kart does not make it so. Despite my go-kart assertion, the sheriff will still require me to have a license to drive my automobile.
If I were truly uncertain whether my vehicle was a car or a go-kart, I could consult with the DMV and get a definitive answer. In ambiguous cases, study investigators can consult with an IRB to determine whether or not their study is classified as human research. TWC authors have provided no evidence that they sought an opinion from an IRB about the nature of their study.
Study gets published!
The TWC ivermectin/mebendazole “study” — Real-world Clinical Outcomes of Ivermectin and Mebendazole in Cancer Patients: Results from a Prospective Observational Cohort — was published in the journal Anticancer Research on May 27, 2026. Anticancer Research is not a top-tier journal, but it is an indexed, peer-reviewed journal.
According to metrics provided by the journal, the article was received April 8; revision received April 20; and received final acceptance April 24, 2026. This is remarkably fast in the publication business. The time from submission to review, to first decision, to revision, to re-review, and to acceptance was a mere 16 days.
The published version of the paper differs little from the version available for download on TWC’s website, with a notable exception. The TWC version contains this disclaimer [emphasis mine]:
Institutional Review Board (IRB) Statement: This project was conducted as a retrospective analysis of a prospective clinical program evaluation. Consistent with established frameworks for quality improvement and internal assessment of clinical services, the project utilized voluntary, patient-reported data. As such, it did not meet the definition of human subjects research and did not require Institutional Review Board (IRB) review.
This is the “I have a go-kart” declaration, in which the authors opine that this study did not require IRB approval.
No such declaration appears in the Anticancer Research version. In fact, no statement about IRB approval or informed consent or ethical conduct of the study is mentioned in the published study at all.
In Anticancer Research’s Editorial Policies are the following statements [emphasis mine]:
Ethical Policies and Standards
Authors must adhere to ethical principles in the conduct of their research, including obtaining informed consent from human subjects, minimizing harm to subjects, and protecting their privacy and confidentiality. Research involving human subjects must be approved by an institutional review board or ethics committee and must comply with international ethical guidelines, such as the Declaration of Helsinki, and Title 45, U.S. Code of Federal Regulations, Part 46, Protection of Human Subjects, effective December 13, 2001……. Before starting the study, all used protocols must have an ethical approval from the local Institutional Review Board (IRB) or any other appropriate ethics board to ensure that the study meets national and international guidelines for human experimentation. A written statement that acknowledges this, including the name of the Institutional Review Board and the reference/approval number (if any), must be included in the submitted manuscript. If a non-interventional study does not require ethical approval, or if a study is exempt from an ethics committee, then this should be fully detailed in the submitted manuscript. For an approved study, the name of the Institutional Review Board that approved it must also be given. Ethics approval is required for all studies before the research is conducted. Authors should be prepared to provide additional information to the journal editors upon request.
Notably, the journal requires compliance with externally established ethical principles and standards such as the Declaration of Helsinki and the Common Rule (45 CFR 46). These standards specifically require IRB pre-approval or a detailed accounting of how a study is deemed exempt from such oversight.
An expeditious “Expression of Concern”
At the top of the TWC article on the Anticancer Research website is a box with the statement: “This article has a correction. Please see:” with a link to “Expression of Concern – June 01, 2026.”
What is an “Expression of Concern?
An Expression of Concern is an alert to notify the public that an investigation for an article is underway.
The Committee on Publication Ethics (COPE) is an organization committed to promoting integrity in research publication. The Anticancer Research editorial policy states that they adhere to COPE’s Principles of Transparency and Best Practices in Scholarly Publishing. According to COPE’s guidelines regarding expressions of concern:
Expressions of concern should be issued if an editor of a journal determines that concerns raised about an article are substantial and credible enough to warrant alerting readers, but insufficient information is available to decide whether a correction or retraction is required.
Editors should consider issuing an expression of concern if:
- significant and credible concerns have been raised but the evidence is unclear as to whether the work, or parts of the work, are potentially unreliable. The unreliability may be due to error, incorrect analysis, or concerns about research integrity and publication ethics that affect the main findings.
- an institutional, funding, or other formal oversight investigation is ongoing that may result in corrections to the literature based on the reliability of the work.
- the authors have been asked to provide additional information to address the concerns that have been raised, and this information is not immediately available.
- there is a breach in the journal or publisher policy that cannot be resolved (eg, article data were available when the article was published but were later withheld by the authors).
- a resolution is not expected to be reached at all or for some time (eg, several months).
The Expression could be removed if the issue is resolved and the article exonerated. It could be removed after a correction. If the concerns are confirmed, the article could be retracted. If the issue cannot be resolved one way or another, the Expression of Concern may be permanently affixed to the article.
What was the expression of concern for TWC’s article?
It is worth quoting the Expression of Concern in full [emphasis mine];
Regarding: Hulscher et al., “Real-world Clinical Outcomes of Ivermectin and Mebendazole in Cancer Patients: Results from a Prospective Observational Cohort,” Anticancer Research Vol. 46, No. 6, pp. 3243-3255, 2026.
The Editorial Board of Anticancer Research is issuing an official Expression of Concern regarding the article cited above. The study was published purely as “hypothesis-generating”, opening the discussion for repurposing of these substances, establishing the ground for future approved, randomized clinical trials. Following publication, serious scientific concerns were raised by the international medical community regarding the verifiability and statistical reliability, and ethical oversight of the underlying dataset.
In formal correspondence to the journal dated June 4, 2026, the authors clarified that the study cohort was not drawn from an unverified consumer survey, but instead comprised “provider-screened cancer patients enrolled in a structured prospective cohort” managed via an internal clinical workflow and licensed provider consultations.
While the Editorial Board acknowledges the authors’ transparency regarding the text-level limitations of self-reported data, a study published in a peer-reviewed oncology journal that reports a “Clinical Benefit Ratio of 84.4%” and specific percentages of “tumor regression” must rest on a verifiably real clinical foundation and adhere to established ethical frameworks for human subject research to maintain its validity in the permanent scholarly record. Anticancer Research does not endorse or condone the unvalidated off-label use of medications for unapproved oncological indications. Disclosing limitations does not exempt a clinical dataset from the foundational scientific requirements of empirical verifiability and independent ethical oversight.
Accordingly, based on the authors’ confirmation of an established clinical provider-patient workflow, the journal is initiating a formal Post-Publication Data Integrity and Ethical Oversight Audit. This investigation will evaluate the mandatory Institutional Review Board (IRB) approval or exemption documentation, the de-identified, source-verified clinical records confirming the baseline cancer diagnoses of the 197 initial participants and the objective medical documentation supporting the reported anatomical regressions.
This Expression of Concern will remain prominently appended to the publication record online and in all indexing databases while this formal data and ethical verification audit is underway.
Considering that the article was published on May 27, and the Expression of Concern is dated only 4 days later, the influx of scientific concerns from the international medical community was swift and persuasive.
What does this mean?
The editors have attached the Expression of Concern to notify readers that there have been concerns raised regarding the ethical oversight of the study and the integrity of the data used in the study. They are also informing readers of actions being taken to resolve these questions. The editors have initiated a “Data Integrity and Ethics Oversight Audit.”
Data Integrity Audit
The editors will be auditing: “…de-identified, source-verified clinical records confirming the baseline cancer diagnoses of the 197 initial participants and the objective medical documentation supporting the reported anatomical regressions.” In other words, the editors are requesting source documents to validate the data used in the analyses. “De-identified” likely means that they will be requesting that the authors redact certain identifying information to protect the identities of the study subjects.
The authors explicitly explain that their analyses were based on patient-reported data from voluntary surveys. The authors did not claim independent review of any clinical records to verify diagnoses or tumor responses. It is unclear how the TWC authors will be able to provide the requested information to the editors.
Ethical Oversight Audit
Here, the editors intend to review the documents necessary to ensure the article adheres to their own Ethical Policies and Standards. They are requesting “mandatory” IRB approval or exemption documents. The ability to produce these documents would have required the authors to have submitted their study protocol to an IRB before starting the project.
If submitted to an IRB, there would be two possible outcomes. The IRB could have determined the project was exempt from IRB oversight. This would have freed them from any ambiguity about the nature and regulation of this project. Alternatively (and more likely) the IRB would have determined that this study is human research, obligating the authors to proceed under the jurisdiction of an IRB. In either instance, these IRB determinations would be in writing, and auditable.
Nothing I have seen in the statements of the authors suggests that they navigated these details. To the contrary, they have argued that these steps were unnecessary.
The fact that such methodological and ethical concerns escaped the editors and peer reviewers does not speak highly of their standards and/or process. Peer review is an imperfect process, and sometimes things slip through the cracks. Kudos to the editors for responding quickly to the outcry from the international medical community.
We will patiently wait to see how this Expression of Concern is resolved.
Stay tuned for further updates.