Stool transplants, which are already being studied as a treatment for colon infections and type 2 diabetes, may also help the body fight cancer, according to new research funded by the U.S. government. In a small clinical trial, some advanced cancer patients who received transplants began to respond to treatments that had not worked before, that stabilized or reduced their tumors.
The goal of a stool transplant is to use a donor’s stool to restore a person’s intestinal microbiome, the neighborhood of bacteria that live along our digestive tract. The intestinal microbiome helps the body regulate everything from metabolism to a properly functioning immune system, and an unbalanced microbiome is believed to cause or increase the risk of many health problems, such as diabetes, inflammatory bowel disease, and certain infections. . By seeding your digestive tract with donor stool bacteria, it seems possible to grow a healthier gut microbiome.
Currently, fecal microbiota transplantation (FMT) is only considered an effective treatment for recurrent gastrointestinal infections caused by Clostridioides difficult, which can be fatal. But there are ongoing tests that test its use for other conditions. This new study, led by researchers at the National Cancer Institute, considered FMT as a kind of reinforcement for another emerging treatment, cancer immunotherapy.
Immunotherapy uses drugs to amplify the immune system’s ability to find and kill cancer cells. These drugs include immune checkpoint inhibitors, which eliminate the natural limiter used by some cancers to prevent detection by T cells. Although immune checkpoint inhibitors have been shown to be promising in the treatment of Advanced forms of cancer, the tumors of some people continue to resist the suppression of the immune system even after treatment. Some researchers have theorized that restoring the intestinal microbiome of these patients will also make these tumors vulnerable to immunotherapy.
G / O Media may receive a commission
“Cancer therapies are often based on stimulating antitumor immune responses, increasing the chance that the gut microbiota may influence host responses to cancer therapy through the immune system,” he said. study author Giorgio Trinchieri, head of the Integrative Cancer Immunology Laboratory at the NCI Center for Cancer Research, told Gizmodo by email.
The study included 15 patients with advanced melanoma, the deadliest form of skin cancer, who had not previously responded to treatment with immune control point inhibitors. These patients received transplants from other patients with advanced melanoma who had responded to therapy (often patients receive them first). a dose of antibiotics to help clean your existing ones microbiome, but not in this study). The donor’s feces were examined for potentially dangerous germs, a precaution that has already become a standard. awake of various diseases and a death related to fecal transplants carrying drug-resistant bacteria in 2019.
Then, six of the 15 patients began responding to treatment. In one patient, their tumors have continued to shrink for more than two years and counting, while another four have had the cancer stabilized, with no signs of disease progression for at least more than a year. (The sixth patient appeared to respond fully to immunotherapy but died shortly after treatment for complications from unrelated surgery).
“In these patients, the tumor progressed rapidly and life expectancy was short,” Trinchieri noted. “Stable disease and tumor contraction would represent a significant improvement in patients’ survival and quality of life and can lead to long-term survival and, in some cases, cure them.”
Both the intestinal microbiome and the immune system of these patients also showed signs of having changed favorably after transplantation, allowing for a better response to therapy. And the transplants themselves were well tolerated, although immunotherapy probably caused minor side effects in some patients, including fatigue. He findings were published in the journal Science on Thursday.
According to Trinchieri, the study is one of the first to show that alteration of the intestinal microbiome can improve a person’s response to immunotherapy. And while this is just a proof-of-concept study, it also demonstrates the potential of targeting the microbiome in general to treat cancer.
Despite this potential, more work needs to be done with larger groups of patients before poop transplants become a standard of care for difficult cancer cases. Research by the team and others is beginning to identify the types of bacteria most likely to improve the immunotherapy response, as well as the patients most likely to benefit from a transplant. They also track patients who have responded to plot disease, while using their donated poop for other studies.
In the future, this transplant technique — which requires a colonoscopy — may not even be the preferred method of delivery. Instead, Trinchieri said, maybe we could just use a pill that contains bacteria. Fortunately, some studies are already exploring this method, in addition to using FMT for other types of cancer.