I have been writing since 2015 about the importance of the gut microbiome, the bacteria in your intestines, as the response to current cancer immunotherapy drugs like Keytruda, Opdivo, and Yervoy.  This is also discussed in detail in my book. There have been continued advances since my book came out. One was the availability of a keystone bacteria in a supplement called Akkermansia. Before this, if you did not have this bacteria, a fecal transplant taking stool from one person to another might be the only answer to boost responses to immunotherapy. More recently, an FDA-approved fecal transplant called Rebyota has become available. It is approved for recurrent C Diff infection, so its use in cancer immunotherapy is off-label. This limits its availability as many doctors will not want to prescribe it, and insurance won’t cover it.

We have been using Rebyota in patients we identified with a poor microbiome or patients who previously failed immunotherapy. Rebyota was the key to turning many from immunotherapy failure to success. Indeed, this is a small amount of patients, and more studies are needed. However, for patients, this can be an option off-label and is worth the cost.

Reference: Helen Albert, 09 Ago 2023, Cancer: The Next Microbiome Frontier, https://www.insideprecisionmedicine.com/news-and-features/cancer-the-next-microbiome-frontier