The treatment is a form of immunotherapy — using the body’s own defense system to fight off pathogens — and involves injecting a “vaccine” made of two types of immune-stimulating agents directly into tumors.
Researchers found that by using this method, tumors in mice were completely eliminated within 10 days. What’s more, the team discovered that within 20 days, even tumors that hadn’t been treated had vanished.
The treatment is novel in, among other things, its specificity. Individual types of cancer can be targeted, with the vaccine being adjusted accordingly. In the case of Stanford’s experiment with mice, for instance, the disease was lymphoma.
In the study, published in Science Translational Medicine, all but three of the 90 mice treated were cured of the cancer on the first try. In the few cases where that didn’t happen, tumors were eradicated after a second injection. The vaccine did not, however, affect other types of diseases in the animal’s body.
In addition to being a relatively inexpensive form of treatment, the team’s method is also far less invasive. Other types of immunotherapy require the activation of the body’s entire immune system, and some even require that cells be removed from the body and genetically engineered before they can fight off cancers.
“Our approach uses a one-time application of very small amounts of two agents to stimulate the immune cells only within the tumor itself,” Dr. Ronald Levy, professor of oncology and senior author of the study, told Stanford Medicine News Center. “In the mice, we saw amazing, body wide effects, including the elimination of tumors all over the animal.”
Of the two immune-stimulating agents that make up the vaccine, one is already approved for use in humans. The other has been tested in unrelated clinical trials. A trial has already been launched to test the effectiveness of the Stanford treatment on human patients with lymphoma.
If all goes well, Levy says, the new treatment could be a game-changer in how doctors approach the treatment of cancers:
“I don’t think there’s a limit to the type of tumor we could potentially treat, as long as it has been infiltrated by the immune system.”
Immunologist Keith Knutson of the Mayo Clinic in Jacksonville, Florida, who was not involved with the research, told Science Magazine that, at a minimum, the findings open up new doors.
“This is a very important study,” Knutson said. “It provides a good pretext for going into humans.”
Drew Pardoll, an immunologist at the Bloomberg-Kimmel Institute for Cancer Immunotherapy in Baltimore, Maryland, who was also not involved in the study, was especially struck by the fact that the vaccine targets tumors in the body that aren’t even directly treated.
“The data is very impressive, particularly for the uninjected tumors,” he told Science Magazine, adding that the Stanford researchers “deserve a lot of credit” for their work.