Researchers at Stanford University’s School of Medicine have made a breakthrough in a new cancer treatment experiment.
According to a study, injecting two immune-stimulating agents directly into tumors in mice can eliminate all traces of cancers in the animals, including cases of distant, untreated metastases.
Eighty-seven percent of 90 mice were cured of cancer with this approach. Cancer recurred in three of the mice, but the tumors regressed after a second treatment.
“When we use these two agents together, we see the elimination of tumors all over the body,” said Dr. Ronald Levy, professor of oncology. “This approach bypasses the need to identify tumor-specific immune targets and doesn’t require wholesale activation of the immune system or customization of a patient’s immune cells.”
The approach works for many different types of cancers, including those that arise spontaneously.
The local application of very small amounts of the agents could serve as a rapid and relatively inexpensive cancer therapy. It is unlikely to cause adverse side effects seen with bodywide immune stimulation.
One agent is currently already approved for use in humans; the other has been tested for human use in several unrelated clinical trials, the study said.
A clinical trial was launched in January to test the effect of the treatment in patients with lymphoma. The current clinical trial is expected to recruit about 15 patients with low-grade lymphoma.
HOW IT WORKS
Since the two agents are injected directly into the tumor, only T cells that infiltrated it are activated. The T cells are then “prescreened” by the body to recognize only cancer-specific proteins.
Some of these T cells then leave the original tumor to find and destroy other identical tumors throughout the body.
This approach worked in laboratory mice with transplanted mouse lymphoma tumors in two sites on their bodies. Injecting one tumor site caused the treatment of that tumor site and the other injected tumor.
Similar results were found in mice bearing breast, colon and melanoma tumors, the researchers found. Treating the first tumor often prevented the occurrence of future tumors and increased the animals’ life span, the study found.