Concomitant antibiotics (ATBs) use and survival outcomes in patients (pts) with muscle-invasive bladder cancer (MIBC) treated with neoadjuvant pembrolizumab (PURE-01 study).

449 Background: Administration of single-agent neoadjuvant immunotherapy (IO) proved to be effective and safe in the treatment of MIBC, and the identification of reliable predictors of treatment-failure would allow a more precise implementation in clinical practice. In advanced/metastatic urothelial carcinoma, ATB therapy has a negative impact on IO efficacy by modulating the intestinal microbiota towards a detrimental state of dysbiosis,...