High fibre diet important for best results with immunotherapy

Consuming a high fibre diet and increasing levels of a family of bacteria called Ruminococcaceae, stabilises the cancer, improves survival and significantly increases the effectiveness of immunotherapy drugs.

The main purpose of this research study (1) was to look at the best way of handling immunotherapy drugs, often called immune checkpoint blockade or ICB, now widely used in treating many cancers. 

Attacking T-cells are sometimes blocked by proteins, as is the surface of cancer cells. As a result, there are less attackers and a poorer visibility of the cancer cell. Immunotherapy drugs such as PD-1 (Nivolumab and Pembrolizumab) block these blocking proteins or checkpoints, on the T-cells; PD-L1 drugs, such as ipilimumab, block the checkpoint blockers on the cancer cells.

In a major Worldwide study on Melanoma led by the University of Texas and involving Oregon State University College of Pharmacy, researchers have shown that positive changes to the gut microbiome were linked to stabilisation in melanoma growth, improvements in survival, and a significantly improved performance with immunotherapy. 

In previous studies covered by CANCERactive from Georgia Medical School, the simultaneous use of antibiotics was shown to inhibit the performance of immunotherapy drugs.

The research was in two parts: an observational study involving people being treated for melanoma with a large percentage on immunotherapy; and a mouse model where the mice had been given melanoma.

Professor Andrey Morgun of Oregon State, an expert in microbial communities pointed to the clear finding in both parts of the research that results were significantly better where higher fibre intake was increased; it was linked to significantly lower disease progression. In the mice, a Transkingdom Network Analysis showed that the high fibre diet caused large increases in a particular family of bacteria - Ruminococcaceae - and this was also observed in previous studies with humans and this current research. This family is never included in mass market probiotics. Not surprisingly, the addition of a probiotic had no effect on improved drug performance and increased survival in either study. 

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Reference

1.  Dietary fiber and probiotics influence the gut microbiome and melanoma immunotherapy response. Science, 2021; 374 (6575): 1632; Christine N. Spencer, Jennifer L. McQuade, Vancheswaran Gopalakrishnan, John A. McCulloch, Marie Vetizou, Alexandria P. Cogdill, Md A. Wadud Khan, Xiaotao Zhang, Michael G. White, Christine B. Peterson, Matthew C. Wong, Golnaz Morad, Theresa Rodgers, Jonathan H. Badger, Beth A. Helmink, Miles C. Andrews, Richard R. Rodrigues, Andrey Morgun, Young S. Kim, Jason Roszik, Kristi L. Hoffman, Jiali Zheng, Yifan Zhou, Yusra B. Medik, Laura M. Kahn, Sarah Johnson, Courtney W. Hudgens, Khalida Wani, Pierre-Olivier Gaudreau, Angela L. Harris, Mohamed A. Jamal, Erez N. Baruch, Eva Perez-Guijarro, Chi-Ping Day, Glenn Merlino, Barbara Pazdrak, Brooke S. Lochmann, Robert A. Szczepaniak-Sloane, Reetakshi Arora, Jaime Anderson, Chrystia M. Zobniw, Eliza Posada, Elizabeth Sirmans, Julie Simon, Lauren E. Haydu, Elizabeth M. Burton, Linghua Wang, Minghao Dang, Karen Clise-Dwyer, Sarah Schneider, Thomas Chapman, Nana-Ama A. S. Anang, Sheila Duncan, Joseph Toker, Jared C. Malke, Isabella C. Glitza, Rodabe N. Amaria, Hussein A. Tawbi, Adi Diab, Michael K. Wong, Sapna P. Patel, Scott E. Woodman, Michael A. Davies, Merrick I. Ross, Jeffrey E. Gershenwald, Jeffrey E. Lee, Patrick Hwu, Vanessa Jensen, Yardena Samuels, Ravid Straussman, Nadim J. Ajami, Kelly C. Nelson, Luigi Nezi, Joseph F. Petrosino, P. Andrew Futreal, Alexander J. Lazar, Jianhua Hu, Robert R. Jenq, Michael T. Tetzlaff, Yan Yan, Wendy S. Garrett, Curtis Huttenhower, Padmanee Sharma, Stephanie S. Watowich, James P. Allison, Lorenzo Cohen, Giorgio Trinchieri, Carrie R. Daniel, Jennifer A. Wargo.