Dec. 31 (UPI) -- Women with advanced breast cancer may have a new weapon in their fight against the disease -- a modified form of immunotherapy.
CAR-T immunotherapy, in which T cells from a patient's immune system are modified to target cancer cells, has been most effective in the treatment of B-cell leukemia or lymphoma, both of which are cell-based, rather than solid-tumor cancers like breast cancer.
Adding a molecule found in immune cells called cGAMP to standard CAR-T boosts its efficacy in breast cancer by encouraging the body's immune cells to attack solid tumors, according to the authors of a study published Thursday by the Journal of Experimental Medicine.
The success of this boosted CAR-T in mice used for the study may be a potential "game changer," researchers said.
"Our approach offers a new way to enhance the function of CAR-T cells in breast cancer that leads to tumor elimination in the majority of animals treated," study co-author Dr. Jonathan S. Serody told UPI.
"To our knowledge, this approach offers the first way to provide curative therapy to treat advanced breast cancer using CAR-T cells, [as] previous approaches have not successfully treated advanced breast cancer," said Serody, director of the immunotherapy program at the University of North Carolina's Lineberger Comprehensive Cancer Center.
In CAR-T therapy, cancer-fighting T cells are harvested from the blood of cancer patients and augmented with a chimeric antigen receptor, or CAR, which targets the proteins in cancer cells, breaking them down, according to the American Cancer Society.
The T cells are then returned to the patient, via infusion.
For CAR-T cell therapy to be effective, T cells infused back into patients have to be able to go to the site of a tumor, which doesn't happen in the case of solid tumors such as breast cancers.
For the study, using mice with breast cancer, mice injected with cGAMP-boosted CAR-T therapy produced more T cells that migrated to the tumor site, reducing tumor growth and improving survival, according to the researchers.
cGAMP is known to be a stimulator of genes that strengthen the human immune response to tumors, the researchers said.
They hope to study the approach in humans by 2022, starting with patients with head and neck cancers first. If it shows promise in these patients, they will try it in those with breast cancer, Serody said.
"There does appear to be a slight increase in toxicity from the CAR-T cells using this approach compared to previous approaches used to treat breast cancer [but] this toxicity is common for patients with leukemia or lymphoma and there are ... approaches to manage this side-effect," he said.