A team of researchers in the United States has successfully shrunk cancerous tumors in animal subjects using a modified bacterial injection of Clostridium novyi. Now, their studies show that they have successfully done the same with one human subject. Their data shows that the bacterial injection was able to induce a strong and accurate anti-cancer response within the tumors that caused the destruction. Details about this research are in the Science Translational Medicine journal.
The role of the clostridium bacteria in cancer therapy has been understudies for years. This specific bacterium is able to survive in environments with low oxygen levels, allowing it to survive at the center of a solid cancer tumor. It is because of this "exquisitely specific" feature of Clostridium that is able to destroy tumor cells while leaving healthy tissue unharmed.
Associate professor of oncology at the Johns Hopkins Kimmel Cancer Center, Prof. Shibin Zhou, is the lead author of this new study, but he has been studying the anti-cancer properties of the Clostridium bacteria for 10 years now. His team became interested in the bacteria's relationship to cancer after observing how some cancer patients contracted serious bacterial infections and then appeared to go into remission. They did initial studies on soft tissue tumors that are local your dads and have metastasized onto normal tissues. They were intrigued by the fact that the bacteria only attacked the oxygen-starved tumor cells and that they did not germinate in the surrounding healthy, normal tissues.
For this particular study, Prof. Zhou and his colleagues modified the C. novyi bacterium by removing it's toxin-producing genes, and called it C. novyi-NT. They administered this modified bacteria injection directly into 16 naturally occurring tumors and dogs. Six of the subjects showed anticancer response within the first 21 days of the first injection, where three showed completely eradicated tumors while the other three shrank by at least 30%. The researchers have also begun testing the drug in a human subject with an abdominal soft tissue tumor, as well as one on her arm. Following the injection, there was a significant reduction in the size of the tumor.
According to Prof. Zhou, "We expect that some patients will have a stronger response than others, but that's true of other therapies as well. Now, we want to know how well the patient can tolerate this kind of therapy."
