Impact of antibiotic treatment on efficacy of anti-PD-(L)1 monotherapy for lung cancer or melanoma

Antibiotic treatment may reduce the efficacy of cancer immunotherapy by disrupting the gut microbiome. A retrospective study at five centers in Finland evaluated the impact of antibiotic therapy within three months before the start of anti-PD-(L)1 monotherapy among patients with lung cancer or melanoma. In survival analyses, antibiotic treatment was associated with worse overall survival in NSCLC patients and melanoma patients, and with worse progression-free survival in NSCLC patients but not melanoma patients. In multivariable analyses, antibiotic treatment was not an independent risk factor for inferior OS and PFS in melanoma, but was associated with inferior OS (HR 2.12; 95% CI 1.37-3.28) and inferior PFS (1.65; 1.10-2.47) in NSCLC after adjustment for other factors.