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Promise and Progress - Cancer-Fighting Bacteria

Promise & Progress - A Spectrum of Achievements

Cancer-Fighting Bacteria

Date: January 15, 2015

A modified version of the bacterium Clostridium novyi (C. novyi-NT) produced a strong and precisely targeted antitumor response in studies of animals and humans.

The bacteria thrive in oxygen-poor environments, making it ideal for treatment of oxygen-depleted areas of tumors where radiation therapy and chemotherapy do not work well. To make it safe for therapy, the Kimmel Cancer Center scientists engineered the bacteria to remove its toxin-producing genes. 

Researchers tested the bacteria-based treatment in 16 pet dogs being treated by veterinarians for naturally occurring tumors. Six of the dogs had some response, including three that had complete eradication of their tumors. 

An MD Anderson Cancer Center patient with an advanced soft tissue tumor in her abdomen received a direct injection of the bacteria spores in a tumor that had spread to her shoulder and experienced a significant reduction of the tumor in and around the bone.  Doctors are encouraged by the patient’s response but say they have not treated enough people to be sure if the same spectrum of responses observed in dogs will translate to humans.  However, they say dogs provide a good glimpse into what may happen in humans because they develop tumors spontaneously and are treated with many of the same cancer drugs.

Researchers also tested the bacteria injection in rats with implanted human glioma brain cancer cells.  The treatment killed tumor cells and spared surrounding normal cells while also extending survival.

The study of the bacteria treatment in humans is ongoing. “One advantage of using bacteria to treat cancer is you can modify these bacteria relatively easy to equip them with other therapeutic agents, or to make them less toxic, as we have done here,” says Shibin Zhou, M.D., Ph.D., director of experimental therapeutics at the Kimmel Cancer Center’s Ludwig Center for Cancer Genetics and Therapeutics.  He and his colleagues began exploring C. novyi-NT’s cancer fighting potential a decade ago after reading 100-year-old accounts of patients who experienced cancer remissions subsequent to serious bacterial infections.  Zhou says an added advantage to the bacteria therapy is that infected tumors should also generate a strong immune response against cancer cells.

The research was funded by BioMed Valley Discoveries Inc., the Virginia and D.K. Ludwig Fund for Cancer Research, the Maryland Cigarette Restitution Fund, the Commonwealth Foundation, Swim Across America, the Burroughs Wellcome Career Award for Medical Scientists, Voices Against Brain Cancer, the Sol Goldman Pancreatic Cancer Research Center, the Johns Hopkins Clinician Scientist Award, the National Institutes of Health’s National Cancer Institute (CA129825 and CA062924) and the National Institute of Neurological Diseases and Stroke (R25 NS065729).  For licensing disclosures go to

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