Efficacy of immunotherapy, gut microbiota and impact of antibiotic use: are there confounding factors?

Excerpt

The inter-relationship between host microbiota and immunotherapy by checkpoint inhibitors (CPI) is currently actively investigated at experimental, pre-clinical and clinical levels [1]. It has recently been shown that tumor expression of chemokines associated with T-cell infiltration can be stimulated by gut bacteria, and reduced by antibiotic treatment [2]. Antibiotics may impair gut microbiota and their use is logically suspected to have a deleterious impact on the clinical outcome of patients treated with immune checkpoint inhibitors [2]. There is by consequence a current view bridging antibiotic use, impaired gut microbiota and subsequently negative impact on immune checkpoint inhibitors efficacy which stimulates clinical investigations [3]. Specific clinical studies indicate a poor clinical benefit in patients undergoing immunotherapy with a history of previous antibiotic use [4]. …