Complete Response To Tislelizumab In A Muscle-Invasive Urothelial Carcinoma After Surgery Associated With Tumor Mutational Burden High: A Case Report
Abstract Muscle-invasive urothelial carcinoma (MIUC) is a highly aggressive urothelial carcinoma. Radical cystectomy (RC) is standard of treatment, but still more than 50% patients with cancer invading the muscularis propria or involving the regional lymph nodes will have metastatic recurrence. In CheckMate274 study, programmed cell death-1 (PD-1) inhibitor nivolumab as adjuvant treatment has shown effective for patients with MIUC. Tislelizumab is an anti-human PD-1 monoclonal IgG4 antibody which was specifically engineered to minimize FcɣR macrophage binding to abrogate antibody-dependent phagocytosis. But there is no report of tislelizumab as adjuvant treatment in MIUC currently. Here, we report a case of MIUC in a patient with PD-L1-negative, microsatellite stable (MSS), high tumor mutational burden (TMB-H) obtained complete response (CR) receiving tislelizumab therapy after surgery. Progression-free survival (PFS) exceeded 6 months since tislelizumab treatment. To our knowledge, this is the first reported case of MIUC patient with PD-L1-negative, MSS and TMB-H who responded well to tislelizumab as adjuvant treatment. However, we still need more studies to assess the efficacy of tislelizumab as adjuvant treatment in MIUC and to confirm that TMB is a predicted biomarker of tislelizumab for efficacy.