anaerobic bacteria injections can reduce tumors in rats, dogs and humans -
At the bottom of most tumors are areas that remain untouched by chemotherapy and radiotherapy. Those annoying spots lack of blood and oxygen needed for traditional therapies work, but provide the perfect target for a new cancer treatment using bacteria that thrive in low oxygen conditions. Now, researchers have shown that injection of a weakened version of one of these anaerobic bacteria - the microbe Clostridium novyi -. Can reduce tumors in rats, pet dogs, and a human
The results of BioMed Valley Discoveries and a national team of collaborators show that C. novyi -NT a Version without the ability to do certain toxins can act as a new type of "biosurgery" eat away tumors in hard to reach places. Tumor tissue excise bacteria in an accurate localized that spares surrounding normal tissue. The study - which represents a new take on an approach first tried it a century ago - indicates that further testing of this agent in selected patients is warranted
"We are encouraging signs that this bacteria could be used to. treat some inoperable tumors, and that could give hope to some patients who do not have other options, "said Saurabh Saha, MD, Ph.D, researcher longtime cancer to BioMed Valley Discoveries and lead author of the study. "But we are still in the early stages, and need to assess the safety and efficacy of treatment, as well as exploring how it works in combination with other treatments against cancer."
The study was published Aug. 13, 2014, in Science Translational Medicine .
The idea of using bacteria to fight back against cancer dates to the 180s, when the cancer researcher William Coley noticed that some patients who developed postoperative infections went into remission or have even been cured of their disease. Despite the initial promise of the approach, progress was slow for the next century.
More than a decade ago Bert Vogelstein, MD, a cancer researcher at Johns Hopkins Medical School and one of the co-authors study tested a number of microbes before determine a particularly promising called Clostridium novyi . Because C. novyi is extremely sensitive to oxygen, it would push inside the core poor in oxygen tumors, but stop once it has reached healthy tissue. In previous studies, Vogelstein and colleagues tame bacteria further by removing its ability to toxins and then injected intravenously to experimental animals. Although bacterial treatment had dramatic effects in a third of mice and rabbits, no complete responses were seen in dogs with naturally occurring cancers.
Dr. Saha and colleagues BioMed Valley Discoveries wondered whether this failure was due more to the route of administration of the therapy itself. A problem with the intravenous administration is the low proportion of spores that are actually tumors. The researchers hypothesized that the injection of spores directly into tumors not only overcome this problem, but may also trigger localized inflammatory and immune responses against tumor cells.
The researchers tested C. novyi -NT injection directly bacteria in tumors in pet dogs with naturally occurring cancers and whose owners volunteer for trial . Each dog received one to four cycles of the new treatment, consisting of a single injection of 100 million spores directly in the target tumor. Sixteen dogs evaluated after treatment, three had significant shrinkage of their tumors and three had tumors that were completely destroyed.
The next step was to try the treatment in humans. The first patient to enroll in the Phase I Investigational study was a 53 year old woman with retroperitoneal leiomyosarcoma whose disease despite eight cycles of chemotherapy and radiation, had spread to her liver, lungs, abdomen, arm and the shoulder. The researchers injected 10,000 spores in metastatic tumor of the right shoulder of the patient. Within days, analysis and CT biopsies showed that the bacteria had infiltrated the tumor and began to destroy the tumor cells. Weeks later, a follow-up MRI revealed a significant amount of the tumor has been destroyed. As a result of the treatment, the pain to the patient's shoulder subsided and she was able to move his arm again.
Studies in other patients are currently ongoing at multiple sites to test the safety and effectiveness of this new approach. Although these results are preliminary, the researchers believe that C. novyi -NT could be part of a new arsenal of immunotherapies that the first immune system of a patient in the fight against cancer.
"Previous preclinical studies have shown that in the process of destruction of the cancer tissue C. novyi -NT generates a powerful innate immune response, which also contributes to the destruction localized tumor, "said Dr. Saha. "The hope is that C. Novyi -NT will be a useful adjuvant for new immune checkpoint inhibitors that can block the ability of tumors to evade a host immune response mediated. It will be interesting to see if a combination of both approaches could destroy the tumors not only at the injection site, but also to all other sites where the cancer may have spread through the body. "
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