Immunotherapy treatments have revolutionized the treatment of cancer.  Immunotherapy encompasses a class of drugs called PD-1 and PD-L1 inhibitors and are marketed under the names Keytruda, Opdivo, Tecentriq, Durvalumab, Libtayo, among others. These drugs bind to receptors on T lymphocytes and cancer cells and block the ability of cancer cells to elude the immune system. Responses can be dramatic and last for years. Unfortunately, immunotherapy treatments only work 30 to 40% of the time.

Often cancer patients only have one chance for immunotherapy to work. What can be done to boost response rates?

Consider the following observations

1. Preliminary studies show the effectiveness of immunotherapy is enhanced by higher levels of short-chain fatty acids in the GI tract (1,2,3,4)

2. Short-chain fatty acids levels in the GI tract can be increased with the consumption of high-fiber fruits and vegetables (5)

3. Probiotics can increase levels of short-chain fatty acids in the GI tract. (6,7,8,9)

Should all patients taking immunotherapy be encouraged to change their diet to incorporate more plant-based foods like fruits and vegetables? Should they all start taking probiotics? If this becomes the standard of care, remember you read about it here first!

References

1. Zhang, et al. Pectin supplement significantly enhanced the anti-PD-1 efficacy in tumor-bearing mice humanized with gut microbiota from patients with colorectal cancer. Theranostics. 2021;11:4155–4170. 

2. Jing N., et al. Ultrafine Jujube Powder Enhances the Infiltration of Immune Cells during Anti-PD-L1 Treatment against Murine Colon Adenocarcinoma. Cancers. 2021;13:3987. 

3. Spencer, et al. Dietary fiber and probiotics influence the gut microbiome and melanoma immunotherapy response. Science. 2021;374:1632–1640.

4. Tomita, et al. Association of Probiotic Clostridium butyricum Therapy with Survival and Response to Immune Checkpoint Blockade in Patients with Lung Cancer. Cancer Immunol. Res. 2020;8:1236–1242. 

5. Markowiak-Kopeć, et al. P. The Effect of Probiotics on the Production of Short-Chain Fatty Acids by Human Intestinal Microbiome. Nutrients 2020, 12, 1107. 

6. Rungsri, P., et al. Effect of fermented milk containing Lactobacillus rhamnosus SD11 on oral microbiota of healthy volunteers: A randomized clinical trial. J. Dairy Sci. 2017, 100, 7780–7787. 

7. Moens F. et al, A four-strain probiotic exerts positive immunomodulatory effects by enhancing colonic butyrate production in vitro. Int. J. Pharm. 2019;555:1–10. 

8. Wang L., Effect of oral consumption of probiotic Lactobacillus planatarum P-8 on fecal microbiota, SIgA, SCFAs, and TBAs of adults of different ages. Nutrition. 2014;30:776–783. 

9. Ho S.-T., et al. Improving effect of a probiotic mixture on memory and learning abilities in d-galactose–treated aging mice. J. Dairy Sci. 2019;102:1901–1909.