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Gregory J. Riely, MD, PhD
Gregory J. Riely, MD, PhD
Posted: Tuesday, August 20, 2024
When the bacterium Escherichia is present within advanced non–small lung cancer (NSCLC) tumors, a more immunostimulatory tumor microenvironment within the lungs may be present, and that may enhance patient survival. These preliminary results, based on a study of the intratumoral microbiomes of 958 patients treated with immune checkpoint inhibitor therapy, build on similar preclinical evidence, said Arielle Elkrief, MD, of Memorial Sloan Kettering Cancer Center, New York, and colleagues in the Journal of Clinical Oncology.
Ultimately, manipulating the tumor microbiome to enhance immune cell infiltration could be a novel strategy to induce or add to antitumor immunity. The association between intratumoral bacteria and the response to immune checkpoint inhibitor therapy deserves further study, they declared.
Based on these investigational findings, intratumoral Escherichia was associated with significantly longer overall survival in patients with NSCLC who were treated with single-agent immunotherapy. Patients with intratumoral Escherichia had significantly longer overall survival than those without (16 vs 11 months; P = .0065). However, no significant differences in overall survival were noted among patients with or without intratumoral Escherichia who had been treated with combination chemoimmunotherapy.
“The association with overall survival in the single-agent immune checkpoint inhibitor cohort remained statistically significant in multivariable analysis adjusting for prognostic features including PD-L1 expression (P = .023),” wrote the team. “The findings were further validated in an external independent cohort of 772 patients.”
Intratumoral Escherichia was known preclinically to be associated with a proinflammatory tumor microenvironment and decreased metastases, noted Dr. Elkrief and co-investigators. In past work, Escherichia coli that expressed the bacterial cytolytic pore-forming toxin ClyA was seen to suppress metastatic tumor growth and prolong survival in mice. Most recently, they noted, E coli–specific CXCL13-producing follicular helper CD41 T cells in the tumor microenvironment of bladder cancer were shown to be associated with the clinical efficacy of neoadjuvant PD-1 blockade.
Disclosure: For full disclosures of the study authors, visit ascopubs.org.
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