Transplanting microbes from feces shows promise of boosting melanoma therapy
CANCER DIGEST – July 9, 2023 – In a multi-center safety trial, researchers have shown that transplanting microbiota from healthy donors is safe and shows promise of improving response to immunotherapy in patients with advanced melanoma, a deadly form of skin cancer. The results were published July 6, 2023 in the journal Nature Medicine.
Immunotherapy stimulates the body’s immune system to attack cancer, and has been shown effective in people with a variety of cancers including melanoma, where it is effective in 40 to 50 percent of patients. Research in other diseases has shown that the human microbiome, the array of microbes in the body, plays a role in whether a person responds to immunotherapy.
“In this study, we aimed to improve melanoma patients’ response to immunotherapy by improving the health of their microbiome through fecal transplants,” Dr. John Lenehan, Medical Oncologist at London Health Sciences Centre’s (LHSC) said in a press release.
Fecal transplants involve collecting stool from healthy donors and extracting the donor’s microbiome and transplanting into the patient’s gut to improve the healthy bacteria. In this study the donor microbes are collected into a gel capsule and taken orally.
Previous studies have shown that many patients who did not respond to immunotherapy had an unhealthy microbiome. At the same time a growing body of research has suggested that improving the microbiome may provide improvement in response to immunotherapy.
In this phase I trial, 20 untreated patients with advanced melanoma from the London, Ontario, Health Sciences Center, the Lawson Health Research Institute, the Centre hospitalizer de l’Université de Montreal, and the Jewish General Hospital were given approximately 40 fecal transplant capsules one week before starting immunotherapy.
The trial showed the fecal transplants were safe and that 65 percent of patients who retained the donor microbiome had a clinical response to a combination immunotherapy treatment. Five patients experienced adverse events associated with the immunotherapy and discontinued the treatment. There were no serious adverse events related to the fecal microbiota transplants.
The goal of the study was to show fecal transplants are safe and did not look at effectiveness of the therapy.
The researchers have now started a large phase II trial that will study the effectiveness of combining microbial transplants and immunotherapy in the treatment of a variety of cancers, including kidney, pancreatic and lung cancer.