Decades-Old Worm Treatment Emerges as Potential Cancer Therapy
In a surprising twist for oncology, a treatment hailed as a potential 'cancer breakthrough' originates not from a novel pharmaceutical discovery, but from a 40-year-old medicine commonly used to treat parasitic worm infections. Researchers from Johns Hopkins University have secured a patent for a new crystal form of mebendazole, named polymorph C, which demonstrates significantly improved efficacy against cancer compared to existing versions of the drug.
How the New Formulation Targets Hard-to-Treat Cancers
The newly patented substance, mebendazole polymorph C, appears to penetrate tumours far more effectively, including those in the brain. This is a critical advancement because most chemotherapy drugs cannot cross the protective blood-brain barrier, making brain tumours notoriously difficult to treat. According to the patent, an oral formulation containing at least 90 percent polymorph C can achieve higher concentrations inside cancer cells than standard mebendazole, potentially making it a more powerful weapon against the disease.
The inventors, Gregory Riggins, Renyuan Bai, Verena Staedtke, Avadhut Joshi, and Tara Williamson, explained that mebendazole exists in three slightly different structures, or polymorphs. Their research focused on polymorph C, which behaves uniquely in the body, travelling to the brain efficiently and reaching tumours at concentrations capable of killing cancer cells.
The patent, officially awarded on September 7, 2021, outlines its potential use against a wide spectrum of cancers. These include aggressive brain tumours like gliomas and medulloblastomas, as well as breast, colon, lung, pancreatic, and thyroid cancers. It also suggests the drug could potentially serve as a chemopreventative agent for individuals at high risk.
Enhanced Efficacy and Overcoming Drug Resistance
In preclinical studies with mice, oral doses of polymorph C achieved levels in both the blood and tumours high enough to produce anti-cancer effects. The researchers reported 'increased tumour suppression' with 'acceptable toxicity', indicating the drug killed cancer cells without causing severe harm to the animals.
A significant focus of the research was overcoming a common problem in oncology: drug resistance. Some cancer cells possess molecular pumps that expel drugs before they can take effect. The Johns Hopkins team proposed combining mebendazole C with a P-glycoprotein inhibitor, such as the drug elacridar, which blocks these pumps. In tests on mice with aggressive brain tumours, this combination extended survival more than polymorph C alone.
The patent also details another approach: pairing the drug with anti-inflammatory medications like celecoxib or sulindac. Since chronic inflammation is linked to cancer development, this combination could help reduce tumour formation in vulnerable populations.
However, the research noted a caveat. While the combination with elacridar was highly effective, prolonged treatment caused significant side effects, including weight loss and even death in some mice, highlighting that careful dosing will be essential in future human trials.
The Road Ahead: From Laboratory to Clinic
One of the most promising aspects of this discovery is the drug's established safety profile. Mebendazole was approved in the early 1970s and is well-understood by doctors, even available over-the-counter in some countries. This long history of safe use means this new formulation could potentially move into clinical trials faster than a completely new chemical entity, accelerating its journey to patients.
The researchers caution that success in mice does not guarantee success in humans. Determining the correct human dosage, understanding how the body processes it, and ensuring it interacts safely with other medications are crucial next steps. The patent describes specific formulations—such as granulated, coated, or micronized versions—designed to improve absorption, all of which require further development.
If clinical trials confirm the promise shown in the lab, mebendazole could become a rare example of a cancer therapy that is not only effective and affordable but also based on a medication doctors already know and trust. For patients facing some of the deadliest forms of cancer, this old medicine may indeed offer a surprising and hopeful new path forward.
