A dog dewormer for cancer has sparked hope and controversy after it was used to treat Joe Tippens’ malignant condition. He’s not the first person to rely on this “dog medicine” to fight their disease, but his story of survival has doctors scratching their heads and others raising their eyebrows.
The dog dewormer is called fenbendazole. It’s a broad-spectrum antiparasitic drug commonly prescribed to dogs to treat parasites and hookworms. It’s also used to treat certain gastrointestinal conditions in humans, including inflammatory bowel disease and stomach ulcers.
When a human takes this medication, the drug travels to the bloodstream where it destroys certain types of cancer cells. It works by disrupting the structure of the cellular microtubules that keep cancer cells from dividing or moving, causing them to die or disappear. It can also block the growth of new tumors by inhibiting the production of a protein that cancer cells use to multiply.
While fenbendazole’s safety for human use has been established, its effectiveness as an anticancer drug has not. But it has been shown to kill cancer cells in animal studies. Since the anecdotal stories of people using fenbendazole as part of their cancer treatment have gained popularity, research has been intensified to understand its potential role in fighting cancer.
A few years ago, Penn Vet researchers led by Dr. Yvonne J. Paterson tested a promising new immunotherapy in dogs with osteosarcoma, a bone cancer that can be difficult to treat with chemotherapy or surgery. They injected the dogs with genetically engineered bacteria that produce the HER2 cancer-causing protein and then taught the animals’ own immune systems to seek and destroy the HER2-positive cancer cells.
Unlike drugs approved for human use, those developed for veterinary purposes go through an additional round of testing before they can be sold to pet owners. This process is known as a phase III clinical trial. In a phase III trial, veterinarians administer the drug to a small number of healthy pets, as well as to patients with a particular health problem. This helps researchers identify any health issues that may be associated with the drug and how it should be administered.
The HER2 immunotherapy that Yvonne Paterson developed has now been used to treat more than 50 dogs with osteosarcoma. Some of these animals have survived for more than five years. Other dogs treated with the HER2 immunotherapy have even been cured of their cancer. These results suggest that the approach has the potential to be effective in other cancers, too. But it’s important to keep in mind that most cancer treatments — whether chemotherapy or radiation — aren’t guaranteed to work, and many come with serious side effects. Hopefully, further research will help develop more targeted approaches that offer better chances of success. For example, scientists are now targeting proteins or other substances that are unique to cancer cells and developing therapies that specifically target them without harming healthy cells. In the future, this type of personalized medicine may be more common than it is now. dog dewormer for cancer