Stanford Medicine researchers eliminated cancer in mice by injecting small doses of two separate agents into the animals’ tumors. The immune-stimulating agents removed all cancer — even metastases, or secondary growths away from the cancer’s main location. 

Robert K. and Helen K. Summy Medical School Professor Ronald Levy, who specializes in oncology, spearheaded the study as its senior author.

“In the mice, we saw amazing, bodywide effects, including the elimination of tumors all over the animal,” Levy said in an interview with Stanford News.

The researchers believe their method could reduce the cost of cancer therapy.

The scientists launched a clinical trial using the dual-agent method and are currently recruiting lymphoma patients to participate in their experimental work. One of the agents has been tested in various clinical trials; the other has already been approved for human use.

Levy’s team injected microgram amounts of the two agents — CpG oligonucleotide, an immunostimulant, and an antibody that binds to the tumor site on an OX40 receptor. The pair of agents enters the tumor site to reactivate immune-response cells, or T-cells, that target tumors.

Then, the first agent works with nearby immune cells to amplify the expression of OX40 on the surface of the T-cells, while the second stimulates the T-cells to fight against cancer cells. 

The researchers discovered that transplanting two lymphoma tumors into each mouse and then injecting the dual agents into just one tumor caused both tumors to regress.

Of the 90 mice studied, 87 were cured of cancer and, in the three mice whose cancer recurred, a second treatment led to the tumors’ regression.

The researchers have eliminated cancer in mice with breast, colon and melanoma tumors. The teams believe that their success bodes well for combating cancer in humans as well.

The human clinical trial launched in January will include around 15 patients with low-grade lymphoma.

If successful, Levy hopes that the approach will help doctors surgically remove cancer cells  by preventing the recurrence of unidentified metastases and the development of new tumors.

Contact Felicia Hou at fhou ‘at’ stanford.edu.