Association Between Antibiotic Therapy and Treatment Effectiveness in Patients With Renal Cell Carcinoma Receiving Immune Checkpoint Inhibitors or Tyrosine Kinase Inhibitors.

PURPOSE: It has been theorized that antibiotic therapy (ABT) affects response to immune checkpoint inhibition (ICI) by inducing dysbiosis of the gut microbiome (GM). To investigate the association between ABT and real-world overall survival (rwOS)/progression-free survival (rwPFS) in patients with metastatic renal cell carcinoma (mRCC) receiving ICI versus tyrosine kinase inhibitors (TKIs). METHODS: none). Three-month landmark Kaplan-Meier estimation and log-rank tests were used to compare rwOS/rwPFS among ABT groups. Multivariable Cox proportional hazards models with time-varying coefficients investigated the association between rwPFS, rwOS, ABT, and treatment modality. CONCLUSION: In our observational study, we identified a potential unique and complex association between ABT and rwOS/rwPFS in patients with mRCC receiving ICI. We found a negative correlation between ABT use after treatment initiation or via the oral route on oncologic outcomes in ICI patients. Moreover, there appears to be an ICI-specific negative association of ABT on rwPFS beyond 1 year. Our findings are associative, but they emphasize the importance of antibiotic stewardship in this space.