Bacterium may Help Shrink Tumors that don't Respond to Chemotherapy, Radiation

Some types of cancer can be more difficult to treat than others.

Now, recent findings published in the journal Science Translational Medicine show that when tumors do not respond to radiation or chemotherapy treatments properly, a modified bacterium could lower the risk of the health issue.

The bacterium known as Clostridium novyi was found to successfully form an anti-tumor response when injected into rats, dogs and humans used in the study.

This bacterium is typically found in rich soil that naturally lives in oxygen-deprived settings. Researchers set out to see if it could help kill oxygen-starved cells found in tumors.

For their research, scientists modified the bacterium by removing the genes that are responsible for producing toxins, including those linked to tissue-damaging infections in both cattle and humans.

First, researchers tested the bacterium spores in rats that were given brain tumors called gliomas, tumors that are typically found in the brain or spine. Researchers found that the bacterium's injection was able to kill tumor cells without hurting the healthy ones. Rats that were treated with the injection lived an average of 33 days, while the others who did not receive the injection only lived about 18.

Researchers then used the bacterium in 16 dogs that were diagnosed with tumors that had naturally developed. They modified Clostridium novyi spores to directly inject into the tumors. Twenty-one days following injection, six of the dogs had exhibited an anti-tumor response. Study findings even showed that half were cured of their cancer. For those with lingering health complications, researchers found that the longest tumor shrunk by at least 30 percent. However, they noted that bacterial infection could be a side-effect of the bacterium's use. 

During the study, researchers also began a Phase 1 clinical trial in humans. They directly injected the Clostridium novyi spores into a metastatic tumor in a female patient's arm. The patient also had a soft tissue tumor in her abdomen. Researchers found that the bacterium helped to reduce tumor tissue in and around her bones.

Though the future for a new potential treatment involving the bacterium looks hopeful, researchers said they will need to conduct more research in order to determine if much of its response will fare the same in humans.