The recommended treatment for patients with high-risk non–muscle-invasive bladder cancer (HR-NMIBC) is tumor resection followed by adjuvant Bacillus Calmette-Guérin (BCG) bladder instillations. However, only 50% of patients benefit from this therapy. If progression to advanced disease occurs, then patients must undergo a radical cystectomy with risks of substantial morbidity and poor clinical outcome. Identifying tumors unlikely to respond to BCG can translate into alternative treatments, such as early radical cystectomy, targeted therapies, or immunotherapies. Here, we conducted molecular profiling of 132 patients with BCG-naive HR-NMIBC and 44 patients with recurrences after BCG (34 matched), which uncovered three distinct BCG response subtypes (BRS1, 2 and BRS3). Patients with BRS3 tumors had a reduced recurrence-free and progression-free survival compared with BRS1/2. BRS3 tumors expressed high epithelial-to-mesenchymal transition and basal markers and had an immunosuppressive profile, which was confirmed with spatial proteomics. Tumors that recurred after BCG were enriched for BRS3. BRS stratification was validated in a second cohort of 151 BCG-naive patients with HR-NMIBC, and the molecular subtypes outperformed guideline-recommended risk stratification based on clinicopathological variables. For clinical application, we confirmed that a commercially approved assay was able to predict BRS3 tumors with an area under the curve of 0.87. These BCG response subtypes will allow for improved identification of patients with HR-NMIBC at the highest risk of progression and have the potential to be used to select more appropriate treatments for patients unlikely to respond to BCG.

In high-risk non-muscle invasive bladder cancer (HR-NMIBC), patient outcome is negatively affected by lack of response to Bacillus-Calmette Guérin (BCG) treatment. Lack of response to cisplatin-based neoadjuvant chemotherapy and cisplatin ineligibility reduces successful treatment outcomes in muscle-invasive bladder cancer (MIBC) patients. The effectiveness of PD-1/PD-L1 immune checkpoint inhibitors (ICI) in metastatic disease has stimulated its evaluation as a treatment option in HR-NMIBC and MIBC patients. However, the observed responses, immune-related adverse events and high costs associated with ICI have provided impetus for the development of methods to improve patient stratification, enhance anti-tumorigenic effects and reduce toxicity. Here, we review the challenges and opportunities offered by PD-1/PD-L1 inhibition in HR-NMIBC and MIBC. We highlight the gaps in the field that need to be addressed to improve patient outcome including biomarkers for response stratification and potentially synergistic combination therapy regimens with PD-1/PD-L1 blockade.

Metabolic reprogramming (MR) is an upregulation of biosynthetic and bioenergetic pathways to satisfy increased energy and metabolic building block demands of tumors. This includes glycolytic activity, which deprives the tumor microenvironment (TME) of nutrients while increasing extracellular lactic acid. This inhibits cytotoxic immune activity either via direct metabolic competition between cancer cells and cytotoxic host cells or by the production of immune-suppressive metabolites such as lactate or kynurenine. Since immunotherapy is a major treatment option in patients with metastatic urothelial carcinoma (UC), MR may have profound implications for the success of such therapy. Here, we review how MR impacts host immune response to UC and the impact on immunotherapy response (including checkpoint inhibitors, adaptive T cell therapy, T cell activation, antigen presentation, and changes in the tumor microenvironment). Articles were identified by literature searches on the keywords or references to “UC” and “MR”. We found several promising therapeutic approaches emerging from preclinical models that can circumvent suppressive MR effects on the immune system. A select summary of active clinical trials is provided with examples of possible options to enhance the effectiveness of immunotherapy. In conclusion, the literature suggests manipulating the MR is feasible and may improve immunotherapy effectiveness in UC.

Purpose: Up to 50% of high-risk non-muscle invasive bladder cancer (HR-NMIBC) patients fail Bacillus Calmette-Guérin (BCG) treatment, resulting in a high risk of progression and poor clinical outcomes. Biomarkers that predict outcomes after BCG are lacking. The antitumor effects of BCG are driven by a cytotoxic T cell response, which may be controlled by immune checkpoint proteins like Programmed Death Ligand 1 (PD-L1). Here, we hypothesized that PD-L1 protein expression could serve as a biomarker for BCG-failure. Methods: HR-NMIBC patients who received ≥ 5 BCG instillations were included. Tissue microarrays were constructed from BCG-naïve tumors and recurrences and stained with the PD-L1 (SP142) antibody. PD-L1 status was defined as ≥ 5% tumor-infiltrating immune cells with membrane staining in the tumor area. Clinicopathological associations with PD-L1 positive tumors were investigated, and time-to-event analyses were performed comparing PD-L1 positive vs. negative tumors. Results: 432 BCG-naïve tumors and 160 recurrences were included, and 91% of patients received adequate BCG. In BCG-naïve tumors, PD-L1 was expressed in 7% of patients and PD-L1 expression was associated with stage T1 versus Ta disease ( p = 0.015). PD-L1 expression was not associated with treatment failure after adequate BCG ( p = 0.782) nor with progression-free survival ( p = 0.732). Testing cut-offs of ≥ 1% and ≥ 10% PD-L1 positivity did not alter results. High PD-L1 expression was more frequent in tumor recurrences (14%) as compared to BCG-naïve tumors ( p = 0.012). Conclusion: PD-L1 expression in HR-NMIBC is not a biomarker of response to BCG. However, PD-L1 is higher in a subset of tumors that failed BCG treatment. More research is needed to determine the role of PD-L1 in tumors where BCG treatment failed.

Purpose: The Genomic Analysis of High-Risk Non–Muscle-Invasive Bladder Cancer (GARNER) study investigated FGFR alteration (ALT) frequency and the clinical outcome relationship with Bacillus Calmette–Guérin (BCG) treatment in high-risk non–muscle-invasive bladder cancer (HR-NMIBC). An FGFR predictive response signature (FGFR-PRS) was discovered that identifies patients with an activated FGFR pathway who could potentially benefit from FGFR-targeted therapy beyond those who are FGFR ALT (+). Experimental Design: Pretreatment tumor samples and clinical data were analyzed from 582 BCG-treated patients with HR-NMIBC. FGFR-PRS was discovered using a separate bladder cancer dataset and applied to the GARNER and other bladder cancer cohorts. FGFR-PRS was also applied to in vitro data from urothelial cancer cell lines treated with FGFR-active agents. Results: A total of 31% of pretreatment GARNER HR-NMIBC tumors were FGFR ALT (+), but this was not significantly associated with BCG response. For the subset of patients with paired pre- and post-BCG treatment samples, nearly one-third of pretreatment ALT (+) patients were ALT (−) posttreatment. FGFR-PRS identified patients with an activated FGFR pathway and identified approximately twofold additional patients compared with ALT status alone, and this increase was similar across tumor stage. A positive relationship between tumor growth inhibition and FGFR-PRS score was shown in bladder cancer in vitro models treated with FGFR-active agents. Conclusions: These data provide support for FGFR-targeted therapy use in FGFR ALT (+) HR-NMIBC and describe tumors with shared FGFR pathway–activated biology that is FGFR ALT (−) but FGFR-PRS (+). The latter suggests a broader potential patient population for FGFR-targeted therapy, which will require subsequent validation in patients treated with FGFR-targeted therapy.