Elevated T-cell exhaustion and urinary tumor DNA levels are associated with BCG failure in patients with non-muscle invasive bladder cancer

Abstract

AbstractBackgroundThe functional status of immune cells within the tumor microenvironment and tumor characteristics may explain Bacillus Calmette-Guérin (BCG)-failure in high-risk non-muscle invasive bladder cancer (NMIBC).ObjectiveTo characterize molecular correlates of BCG-failure using a multiomics approach.Design, Setting, and ParticipantsBCG-treated NMIBC patients (n=156) were included. Metachronous tumors were analyzed using RNA-sequencing (n=170) and whole exome sequencing (n=198). Urine samples were analyzed for immune-oncology related proteins (n=190), and tumor-derived DNA (tdDNA; n=192).Outcome Measurement and Statistical AnalysisPrimary endpoint was BCG-failure. Cox regression, Wilcoxon Rank Sum test, t-test or Fisher’s exact test were used.Results and LimitationsBCG caused activation of the immune system regardless of clinical response; however, immune-inhibitory proteins were observed in the urine of BCG-unresponsive patients post-treatment (CD70, PD1, CD5). BCG-failure was associated with post-BCG T-cell exhaustion (p=0.0021). Pre-BCG tumors from patients with post-BCG T-cell exhaustion were characterized by high expression of cell division and immune-related genes. A high post-BCG exhaustion prediction score in pre-BCG tumors was associated with worse post-BCG high-grade recurrence free survival (HGRFS), reflecting BCG-failure (p=0.0084). Pre-BCG tumors of class 2a and 2b were likewise associated with worse post-BCG HGRFS(p=0.0023). Post-BCG exhaustion was observed in patients with high pre-BCG neoantigen load (p=0.023) and mutations in MUC4 (p=0.0007). Finally, absence of post-BCG tdDNA clearance identified patients at high risk of recurrence (p=0.028). The retrospective design, lack of maintenance BCG, and partial overlap in analyses are limitations to the study.ConclusionsBCG failure may be caused by T-cell exhaustion. Tumor subtype and Pre-BCG tumor characteristics may identify patients at high risk of BCG-failure prior to treatment. Urinary measurements have the potential to be used as a real-time assessment of treatment response.Patient SummaryA dysfunctional immune response to BCG therapy may explain lack of response to the treatment.