Impact of prior antibiotic use on the efficacy of nivolumab for non-small cell lung cancer.

Gut microbiota serves an important role in shaping systemic immune responses. Antibiotics cause changes in the gut microbiota that may influence the efficacy of cancer immunotherapy. In the present study, a retrospective analysis of the data from 90 patients treated with nivolumab for non-small cell lung cancer (NSCLC) was conducted. A total of 13 patients were treated with antibiotics prior to nivolumab therapy. The median progression-free survival time in patients treated with antibiotics was 1.2 months [95% confidence interval (CI), 0.5-5.8], while the time for patients who were not treated with antibiotics was 4.4 months (95% CI, 2.5-7.4). The median overall survival time in patients treated with antibiotics was 8.8 months, while it was not reached in those not treated with antibiotics, respectively. The differences between the survival curves with regard to PFS and OS were statistically significant (P=0.04 and P=0.037, respectively). However, in multivariate analysis, no statistically significant association was indicated between survival and prior antibiotic use, although a certain trend concerning the negative influence of antibiotic use was conveyed.