Fecal Transplant Improves Immunotherapy Response

June 21st, 2021

Immunotherapy drugs that work with the body’s immune system to target and attack cancer cells are commonly used to treat certain types of cancers. One specific type of immunotherapy, called anti-PD-1 treatment, has been shown to provide substantial long-term benefits to patients with advanced melanoma. However, only about 40% of melanoma patients respond effectively to anti-PD-1 immunotherapy.

Responsiveness to anti-PD-1 has been associated with composition of the gut microbiome—the community of bacteria and other microorganisms that live within the human digestive system. In promising news, researchers at the University of Pittsburgh, Hillman Cancer Institute, and the National Cancer Institute discovered that changing the gut microbiome can improve responsiveness to immunotherapy in melanoma patients with anti-PD-1 resistance.    

In the study, 15 melanoma patients with a history of resistance to anti-PD-1 immunotherapy drugs were subject to fecal microbiota transplant (FMT) – the transfer of stool from a donor into the colon of the recipient in order to establish a healthier microbiome. As a result of FMT, six of the 15 patients demonstrated newfound responsiveness to anti-PD-1 therapy. Among the responders, the researchers found that microbiome composition shifted significantly toward bacterial species that are associated with responsiveness to anti-PD-1.

Based off of these promising results, co-authors Diwakar Davar, MD, and Hassane Zarour, MD, hope to extend their work to larger clinical trials. The team suggests that future work in the field may involve further characterization of the bacteria and immune system markers that correspond to successful FMT and anti-PD-1 treatment. With this information, healthcare systems may be able to better identify melanoma patients most likely to benefit from microbiome-based therapies in the future.   

Interested in learning about other cancer research studies? Visit Pitt+Me.