Fecal microbiota transplant capsules may ease cancer treatment side effects, study finds

Two Canadian trials reported that fecal microbiota transplant (FMT) capsules were associated with fewer immunotherapy-related digestive side effects in a 20-patient kidney cancer group and higher response rates in some lung cancer (80% vs 39–45%) and melanoma (75% vs 50–58%) patients.

Two Canadian clinical trials published in Nature Medicine tested fecal microbiota transplant (FMT) capsules given alongside cancer immunotherapy. One trial looked at safety and side effects in a 20-patient group with advanced kidney cancer. Separate trials evaluated whether FMT could improve responses to immunotherapy in patients with lung cancer and melanoma. The studies used freeze-dried donor stool processed into oral capsules produced by Lawson in London, Ontario. Key findings: - A phase testing FMT with immunotherapy in 20 kidney cancer patients reported fewer severe immune-related digestive side effects compared with what is typically seen. - In the lung cancer trial, 80% of patients who received FMT responded to immunotherapy versus 39–45% among patients treated with immunotherapy alone. - In the melanoma trial, 75% of patients who received FMT responded, compared with 50–58% for immunotherapy alone. - The capsules were made from healthy donor stool by Lawson; FMT has previously been used in medicine and received regulatory attention for treating C. difficile infections (FDA noted approval for that use in 2022). Summary: The trials reported that FMT capsules were associated with reduced digestive toxicity in a small kidney cancer safety group and with higher response rates in some lung cancer and melanoma patients. Further research is underway, including studies testing FMT in pancreatic and triple-negative breast cancer.