Poop Transplant May Help Cancer Patients Unresponsive to Immunotherapy
Fecal microbiota transplant (FMT) is the process of transferring fecal bacteria from a healthy individual into another individual mainly for the treatment of Clostridioides difficile infection among various other diseases. Now, new research from UPMC Hillman Cancer Center and the National Cancer Institute (NCI) is revealing that it may also facilitate cancer treatment.
The new study saw the stool transplant conducted on patients with advanced melanoma who never responded to immunotherapy and found that FMT seemed to boost their response to anti-PD-1 immunotherapy.
"FMT is just a means to an end," said in a statement study co-lead author Diwakar Davar, M.D., an oncologist and a member of the Cancer Immunology and Immunotherapy Program (CIIP) at UPMC Hillman and assistant professor of medicine at the University of Pittsburgh.
"We know the composition of the intestinal microbiome — gut bacteria — can change the likelihood of responding to immunotherapy. But what are 'good' bacteria? There are about 100 trillion gut bacteria, and 200 times more bacterial genes in an individual's microbiome than in all of their cells put together."
The combination of FMT and anti-PD-1 treatment was given to 15 advanced melanoma patients. Out of these 15, six exhibited either tumor reduction or disease stabilization lasting more than a year, a 40 percent success rate.
"The likelihood that the patients treated in this trial would spontaneously respond to a second administration of anti-PD-1 immunotherapy is very low," said study co-senior author Hassane Zarour, M.D., a cancer immunologist and co-leader of the CIIP at UPMC Hillman as well as a professor of medicine at Pitt.
"So, any positive response should be attributable to the administration of fecal transplant."
Now, the researchers aim to run a larger trial and to evaluate whether FMT may be equally effective in treating other cancers. The results of this phase II clinical trial were published in the journal Science.