Mebendazole Cancer Claims Outrun the Evidence, Experts Warn as Johns Hopkins Patent Fuels Viral Posts
核心洞察
Viral social media posts claim mebendazole is a hidden cancer (搜索) cure, citing a 2021 Johns Hopkins patent on a mebendazole polymorph.
The patent's first inventor says mebendazole's oncology efficacy has not been established through the much-needed larger clinical trials.
Researchers report high doses of the anti-parasitic drug are safe and well tolerated in cancer (搜索) patients, with a reasonable chance of being effective.
The anti-parasitic drug mebendazole has demonstrated preclinical efficacy in targeting multiple cancers, but social media posts describing it as a cancer (搜索) "cure" go beyond what the science supports, according to experts cited by AFP. Additional clinical trials in humans are necessary to establish when, at what dosage, and in which treatment combinations the drug could make an impact.
The claims spread through posts such as an August 29, 2026 Facebook message declaring: "MASSIVE BOMBSHELL: THE CANCER (搜索) INDUSTRY IS HIDING THE CURE! JOHNS HOPKINS HELD THE PATENT ALL ALONG!" The post included a screenshot of a US patent issued in 2021 to researchers at Johns Hopkins University (搜索) in Maryland, titled "Mebendazole polymorph for treatment and prevention of tumors." Similar posts questioning why the institution holds the patent, or alleging an effort to keep an affordable cancer treatment from patients, circulated widely across platforms. Canadian physician William Makis, whom AFP has repeatedly fact-checked for spreading medical misinformation, amplified the claims.
Mebendazole is an anti-parasitic medicine approved to treat worm infections and is available only by prescription in the United States and Canada. The drug is considered a strong candidate for repurposing in oncology as a possible anti-cancer (搜索) therapeutic.
Patent Holder Cautions Against Overreach
Gregory Riggins, a Johns Hopkins professor of neurosurgery and oncology listed as the first inventor on the patent, told AFP that "the efficacy of mebendazole in oncology has not been established through the much-needed larger clinical trials." In a September 4 email, he added: "It is possible it is not effective."
Riggins said his research has shown that high doses of mebendazole "are safe in cancer (搜索) patients, well-tolerated and have a reasonable chance of being effective." He cautioned, however, that the drug will not be for all patients or cancers. The latest evidence suggests it is "best used early in therapy prior to metastasis or as a prevention against tumor recurrence, or as a prevention in individuals who have inherited a high-risk cancer-causing gene mutation," he said.
What the Polymorph C Patent Covers
The patent referenced in the online posts is valid. It was awarded to Riggins and a team of Johns Hopkins researchers who invented mebendazole polymorph C, a specific molecular structure of the medicine. Johns Hopkins Technology Transfer advertised the invention, and Riggins said a company licensed it, though he lamented that the licensee has not yet taken it into clinical trials. The patent's existence, he emphasized, is not proof of a proven cancer (搜索) cure.
The change Riggins and his colleagues made to the crystal structure helped mebendazole become "more effective in brain cancer (搜索) models because it is absorbed better, reaches higher concentrations in the blood plasma and higher, more effective amounts in tumors, including brain cancers," he said.
Robin Feldman, an intellectual property expert who directs the Center for Innovation at UC Law, San Francisco (搜索), described the polymorph C invention as a "secondary patent." Feldman said that while any patent can delay or deter the availability of generic drugs, secondary patents also provide market incentives that can encourage companies to undertake the research and development necessary to move science forward. Adjustments to a drug's dosage or delivery system that demonstrate value "should be able to earn its reward in the market," she told AFP in a September 2 email.
Safety Risks of Unsupervised Use
Riggins cautioned that taking mebendazole is not without risks. "Among the dangers is a potentially dangerous drug interaction with a certain antibiotic and monthly blood tests are needed to monitor liver function and the possibility of anemia (搜索)," he said.
Keith Stewart, University Health Network's vice president for cancer (搜索) and director of Canada's Princess Margaret Cancer Centre, agreed. "Self-medicating with drugs that have not been proven effective for cancer may expose patients to unnecessary risks and could delay or interfere with evidence-based care," he warned in a September 9 email.
While cancer (搜索) patients are understandably interested in all possible treatment options, including research into mebendazole, Stewart told AFP: "There is currently no accepted evidence that it provides a significant benefit in treating human cancers."