Abstract 1168P
Background
Gut microbiota affects immune responses. Antibiotics (ATB) alter gut microbiota and recent data show that ATB influence immune checkpoint inhibitor (ICI) efficacy. In this study, we analysed ATB use in advanced non-small cell lung cancer (NSCLC) who received ICI +/- chemotheraphy (CT).
Methods
We examined patients with advanced NSCLC treated with ICI as monotherapy, dual therapy or combination with CT at Cerrahpasa Medical Faculty between 2014-2020. The primary objective of this study was to assess the impact of ATB use on overall survival (OS), progression free survival (PFS) and objective response rate (ORR) during ICI therapy. We categorized ATB usage as cumulative exposure (including concurrent use of more than 1 ATB or multiple courses of ATB usage), single course (who received a single course of 1 ATB) and no ATB usage. We also performed a subgroup analysis to show the impact of different time periods of ATB exposure on ICI efficacy.
Results
90 patients were included in our analysis. Median age 61; ECOG performance score of patients were 0-1. 80 of 90 received ICI as monotherapy, 1 patient received dual ICI and 9 of 90 received ICI combined with CT. 53 patients had ATB therapy during ICI treatment. 23 of them had single course of ATB and 30 of them had cumulative exposure of ATB. 30 patients had no ATB exposure. When we compared the effects of no ATB usage, single course usage and cumulative exposure on OS, PFS and ORR there was no statistical significance (p=0.116, p=0.881, p=0.586, respectively) There was also no association between ATB usage and smoking status (p=0.371) or metastatic sites (p=0.522). Exposure to ATB in the first 12 weeks was consistently worse than in those who received ATB after first 12 weeks; OS (5.5 vs 41.1 months, respectively, p=0.003), PFS (4.9 vs 25 months, respectively, p=0.001) and ORR (25.9% vs 74.1% respectively, p=0.002).
Conclusions
The exposure of single course or cumulative ATB did not influence ICI efficacy. The detrimental effect of ATB on ICI efficacy was significant when used in the first 12 weeks.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Has not received any funding
Disclosure
All authors have declared no conflicts of interest.