Injected modified bacteria have proven to effectively shrink tumors in humans.
A modified version of the bacteria Clostridium novyi (C. noyvi-NT) was found to produce an anti-tumor responses that could be used as a potential cancer treatment, Johns Hopkins Medicine reported.
C. novyi is found in the soil and can cause tissue damage in certain cases. It thrives in oxygen-poor environments, meaning it can target oxygen-starved cells in tumors that are difficult to treat through other methods. The treatment was also tested in dogs, and proved to produce an anti-tumor response in six of the 16 subjects.
A human patient with an advanced soft tissue tumor in the abdomen received the spore injection directly into the metastatic tumor in her arm; the treatment significantly shrunk the tumor around the bone.
"She had a very vigorous inflammatory response and abscess formation," Nicholas Roberts, Vet.M.B., Ph.D. said. "But at the moment, we haven't treated enough people to be sure if the spectrum of responses that we see in dogs will truly recapitulate what we see in people."
The injections were first administered to rats with implanted brain tumors called gliomas. Microscopic evaluation of these tumors killed tumor cells but did not affect healthy cells nearby; the treatment also prolonged the rats' survival by about 15 days.
Researchers will continue to test the C. noyvi-NT spore injection in humans, but the results of the treatment are not yet available.
"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 patients can tolerate this kind of therapy," Shibin Zhou, M.D., Ph.D said.
In the future the injections could be paired with treatments such as chemotherapy, and this combination has already been studied in mice.
"Some of these traditional therapies are able to increase the hypoxic region in a tumor and would make the bacterial infection more potent and increase its anti-tumor efficiency," said Verena Staedtke, M.D., Ph.D., a Johns Hopkins neuro-oncology fellow. "C. noyvi-NT is an agent that could be combined with a multitude of chemotherapy agents or radiation."
The findings were published Aug. 13 in Science Translational Medicine.
