Is There a Detrimental Effect of Antibiotic Therapy in Patients with Muscle-invasive Bladder Cancer Treated with Neoadjuvant Pembrolizumab?

Abstract In locally advanced and metastatic malignancies, antibiotic (ATB) therapy has a negative effect on immunotherapy efficacy. Therefore, we aimed to evaluate whether ATB therapy and use of specific ATB classes with concomitant neoadjuvant pembrolizumab affected pathologic complete response (ypT0N0) and relapse-free survival (RFS) for patients with clinical T2–4N0M0 bladder cancer enrolled in the PURE-01 study. Of the 149 patients evaluated, 48 (32%) received any concomitant ATB therapy. The ATB class most commonly administered was fluoroquinolones (16 patients; 33%). In the ATB cohort, seven patients (15%) achieved ypT0N0 status, compared to 50 (50%; p  Patient summary The efficacy of immunotherapy for cancer is influenced by several patient and tumor factors, including the use of antibiotics. We found that antibiotics taken at the same time as immunotherapy drugs were associated with lower rates of complete response and of recurrence-free survival among patients with muscle-invasive bladder cancer. These findings need to be confirmed in future studies.