The injection of minute amount of two immune-stimulating agents directly into solid tumors in mice can result in eliminating cancer traces in the animals, including untreated and distant metastases, as per a study conducted at Stanford University School of Medicine.
This approach can be a working method for various kinds of cancer.
The best of this application is that it is relatively inexpensive cancer therapy. Moreover, the adverse side effects can be avoided that is common with body-wide immune stimulation.
“When we use these two agents together, we see the elimination of tumors all over the body,” said Ronald Levy, MD, 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.”
There is one agent that already got approval to be used in humans. The others are undergoing tests for human use in a number of unrelated clinical trials. There was launching of the clinical trials in January for testing the treatment effect in patients with lymphoma.
The approach of some immunotherapy has the reliance to stimulate the immune system throughout the body. Others have the targeting of the naturally occurring checkpoints that would be limiting the immune cells’ anti-cancer activity. Although, these approaches have high success rate, they also represents some downsides – the effects of difficult-to-handle, lengthy preparation and high costs or treatment times.
“All of these immunotherapy advances are changing medical practice,” Levy said. “Our approach uses a one-time application of very small amounts of two agents to stimulate the immune cells only within the tumor itself. In the mice, we saw amazing, body-wide effects, including the elimination of tumors all over the animal.”
The methods adapted by Levy in reactivating the cancer specific T cells with the injection of microgram amounts of two agents into the site of the tumor directly. One, a short stretch of DNA called a CpG oligonucleotide, works with other nearby immune cells to amplify the expression of an activating receptor called OX40 on the surface of the T cells. The other, an antibody that binds to OX40, activates the T cells to lead the charge against the cancer cells. Because the two agents are injected directly into the tumor, only T cells that have infiltrated it are activated. In effect, these T cells are “prescreened” by the body to recognize only cancer-specific proteins.