Breaking Barriers: Modulation of Tumor Microenvironment to Enhance Bacillus Calmette-Guérin Immunotherapy of Bladder Cancer

The clinical management of bladder cancer continues to present significant challenges. Bacillus Calmette-Guérin (BCG) immunotherapy remains the gold standard of treatment for non-muscle invasive bladder cancer (NMIBC), but many patients develop recurrence and progression to muscle-invasive disease (MIBC), which is resistant to BCG. This review focuses on the immune mechanisms mobilized by BCG in bladder cancer tumor microenvironments (TME), mechanisms of BCG resistance, the dual role of the BCG-triggered NFkB/TNFα/PGE2 axis in the regulation of anti-tumor and tumor-promoting aspects of inflammation, and emerging strategies to modulate their balance. A better understanding of BCG resistance will help develop new treatments and predictive biomarkers, paving the way for improved clinical outcomes in bladder cancer patients.

Optimizing outcomes for high-risk, non-muscle-invasive bladder cancer: The evolving role of PD-(L)1 inhibition

Transurethral resection of bladder tumor followed by intravesical Bacillus Calmette-Guérin (BCG) is the standard of care in high-risk, non-muscle-invasive bladder cancer (NMIBC). Although many patients respond, recurrence and progression are common. In addition, patients may be unable to receive induction + maintenance due to intolerance or supply issues. Therefore, alternative treatment options are urgently required. Programmed cell death (ligand) 1 (PD-[L]1) inhibitors show clinical benefit in phase 1/2 trials in BCG-unresponsive NMIBC patients. This review presents the status of PD-(L)1 inhibition in high-risk NMIBC and discusses future directions. PubMed and Google scholar were searched for articles relating to NMIBC immunotherapy and ClinicalTrials.gov for planned and ongoing clinical trials. Preclinical and early clinical studies show that BCG upregulates PD-L1 expression in bladder cancer cells and, when combined with a PD-(L)1 inhibitor, a potent antitumor response is activated. Based on this mechanism, several PD-(L)1 inhibitors are in phase 3 trials in BCG-naïve, high-risk NMIBC in combination with BCG. Whereas PD-(L)1 inhibitors are well characterized in patients with advanced malignancies, the impact of immune-related adverse events (irAE) on the benefit/risk ratio in NMIBC should be determined. Alternative routes to intravenous administration, like subcutaneous and intravesical administration, may facilitate adherence and access. The outcomes of combination of PD-(L)1 inhibitors and BCG in NMIBC are highly anticipated. There will be a need to address treatment resources, optimal management of irAEs and education and training related to use of this therapy in clinical practice.

Precursors of urinary bladder cancer: molecular alterations and biomarkers

Clinical surveillance and follow-up of patients diagnosed with or at risk for urinary bladder cancers represent long-term, invasive, and costly processes for which supplemental biomarker information could help provide objective, personalized risk assessment. In particular, there are several precursors and possible precursors to urinary bladder cancer for which clinical behavior is heterogenous and interobserver variability in histopathologic diagnosis make it difficult to standardize management. This review seeks to highlight these precursor lesions from a diagnostic perspective (including flat urothelial lesions, papillary urothelial lesions, squamous lesions, and glandular lesions) and qualify known multiomic biomarkers that may help explain their behavior, predict patient risk, and acknowledge the nuance inherent to the question of whether these lesions are "benign" or "preneoplastic."

Actionable genomic landscapes from a real-world cohort of urothelial carcinoma patients

BACKGROUND

Recent targeted therapies for advanced and metastatic urothelial cancer have generated enthusiasm, but the actionable genomic landscape of early-stage disease remains largely unknown. Here, we utilized a large, real-world cohort to comprehensively investigate the incidence of genetic alterations with potential therapeutic implications at all stages of bladder cancer.

MATERIALS AND METHODS

We retrospectively analyzed next-generation sequencing (NGS) data from 1,562 bladder cancer patients (stages I-IV) with formalin-fixed, paraffin-embedded tumor biopsies sequenced using the Tempus xT solid tumor assay. Incidence of genetic alterations, tumor mutational burden (TMB), microsatellite instability (MSI), and PD-L1 status were assessed and stratified by bladder cancer stage. For patients with tumor-normal match sequencing (n=966), incidental germline alterations in 50 genes were assessed.

RESULTS

The cohort was composed of 165 stage I-II, 211 stage III, and 1,186 stage IV tumors. TMB-high, PD-L1 positive, and MSI-high status were noted in 14%, 33%, and 0.7% of tumors, respectively, and were similar across stages. Alterations in fibroblast growth factor receptor (FGFR)2/3, homologous recombination repair genes, additional DNA repair gene mutations (ERCC2, RB1, FANCC), and NTRK fusions were detected at similar frequencies across disease stages. We identified a low rate of incidental germline mutations in all tumors (5.2%) and in specific genes: MUTYH (1.9%), BRCA2 (0.5%), and ATM (0.8%).

CONCLUSIONS

Important subsets of patients demonstrate genetic alterations in potentially actionable molecular pathways at all stages. This analysis found minimal variability in these alterations across stages, providing rationale for early identification of genetic alterations and personalization of therapies at all stages for patients with bladder cancer.