The emerging role of immunotherapy in advanced urothelial cancers

Association of Tumor Mutational Burden and Microsatellite Instability With Response and Outcomes in Patients With Urothelial Carcinoma Treated With Immune Checkpoint Inhibitor

BACKGROUND

Microsatellite Instability (MSI) and Tumor Mutational Burden (TMB) are associated with immune checkpoint inhibitor (ICI) efficacy. We examined the association between TMB and MSI status with survival in patients with urothelial carcinoma (UC) treated with ICI.

METHODS

Patients from 15 institutions were treated with ICI monotherapy. Primary endpoint was overall survival and secondary endpoints included observed response rate (ORR), and progression-free (PFS) calculated from ICI initiation. TMB was analyzed as dichotomous (≥10 vs. <10 mut/Mb) and continuous variable.

RESULTS

We identified 411 patients: 203 were treated with ICI 1L/upfront; 104 with 2 + L. For the 1L/upfront: median [m] OS was numerically longer in patients with TMB ≥10 versus TMB <10: mOS 35 versus 26 months (HR = 0.6) and with MSI-H and MSI-S (mOS NR vs. 22 months), though neither association was statistically significant. A statistically significant association was found between TMB (continuous variable) and OS (HR = 0.96, P = .01). For 2 + L: mOS was numerically longer in patients with TMB ≥10 versus TMB <10: (20 vs. 12 months; HR = 0.9); mOS was 12 and 17 months for patients with MSI-H and MSI-S, respectively. Eighty-nine patients received maintenance avelumab (mAV): mOS was longer in patients with TMB ≥10 versus TMB <10: 61 versus 17 months; (HR = 0.2, P = .02) and with MSI-H and MSI-S (NR vs. 24 months).

CONCLUSIONS

Although not reaching statistical significance in several subsets, patients with high TMB and MSI-H had numerically longer OS with ICI, especially with mAV. Further validation is needed.

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.

Immunotherapeutic prospects and progress in bladder cancer

Bladder cancer is one of the most common malignant tumours of the urogenital system, with high morbidity and mortality. In most cases, surgery is considered the first choice of treatment, followed by adjuvant chemotherapy. However, the 5-year recurrence rate is still as high as 65% in patients with non-invasive or in situ tumours and up to 73% in patients with slightly more advanced disease at initial diagnosis. Various treatment methods for bladder cancer have been developed, and hundreds of new immunotherapies are being tested. To date, only a small percentage of people have had success with new treatments, though studies have suggested that the combination of immunotherapy with other therapies improves treatment efficiency and positive outcomes for individuals, with great hopes for the future. In this article, we summarize the origins, therapeutic mechanisms and current status of research on immunotherapeutic agents for bladder cancer.

Y chromosome loss in cancer drives growth by evasion of adaptive immunity

Loss of the Y chromosome (LOY) is observed in multiple cancer types, including 10-40% of bladder cancers1-6, but its clinical and biological significance is unknown. Here, using genomic and transcriptomic studies, we report that LOY correlates with poor prognoses in patients with bladder cancer. We performed in-depth studies of naturally occurring LOY mutant bladder cancer cells as well as those with targeted deletion of Y chromosome by CRISPR-Cas9. Y-positive (Y+) and Y-negative (Y-) tumours grew similarly in vitro, whereas Y- tumours were more aggressive than Y+ tumours in immune-competent hosts in a T cell-dependent manner. High-dimensional flow cytometric analyses demonstrated that Y- tumours promote striking dysfunction or exhaustion of CD8+ T cells in the tumour microenvironment. These findings were validated using single-nuclei RNA sequencing and spatial proteomic evaluation of human bladder cancers. Of note, compared with Y+ tumours, Y- tumours exhibited an increased response to anti-PD-1 immune checkpoint blockade therapy in both mice and patients with cancer. Together, these results demonstrate that cancer cells with LOY mutations alter T cell function, promoting T cell exhaustion and sensitizing them to PD-1-targeted immunotherapy. This work provides insights into the basic biology of LOY mutation and potential biomarkers for improving cancer immunotherapy.

PD-L1 as a biomarker of response to immune-checkpoint inhibitors

Immune-checkpoint inhibitors targeting PD-1 or PD-L1 have already substantially improved the outcomes of patients with many types of cancer, although only 20-40% of patients derive benefit from these new therapies. PD-L1, quantified using immunohistochemistry assays, is currently the most widely validated, used and accepted biomarker to guide the selection of patients to receive anti-PD-1 or anti-PD-L1 antibodies. However, many challenges remain in the clinical use of these assays, including the necessity of using different companion diagnostic assays for specific agents, high levels of inter-assay variability in terms of both performance and cut-off points, and a lack of prospective comparisons of how PD-L1⁺ disease diagnosed using each assay relates to clinical outcomes. In this Review, we describe the current role of PD-L1 immunohistochemistry assays used to inform the selection of patients to receive anti-PD-1 or anti-PD-L1 antibodies, we discuss the various technical and clinical challenges associated with these assays, including regulatory issues, and we provide some perspective on how to optimize PD-L1 as a selection biomarker for the future treatment of patients with solid tumours.

Predicting immune checkpoint inhibitor response in urothelial carcinoma: another step in personalised medicine?

Prediction of treatment response is a crucial issue in individualised treatment for cancer patients. In this context, Nassar and colleagues in the accompanying study published in the British Journal of Cancer analysed retrospectively a cohort of 62 metastatic urothelial cancer patients treated with immune checkpoint inhibitors and of whom not only clinical but also genomic characteristics were available. Combining molecular and clinical factors in a multivariable analysis they identified lack of visceral metastases, neutrophil-to-lymphocyte ratio (NLR) <5, and high single nucleotide variant (SNV) count (≥10) as independent predictors of treatment response.

Comparative Safety of PD-1/PD-L1 Inhibitors for Cancer Patients: Systematic Review and Network Meta-Analysis

Background: Comprehensive evidence comparing treatment-related adverse events (trAEs) among PD-1/PD-L1 inhibitors is unavailable.

Methods: A systematic review and network meta-analysis (NMA) was conducted. Randomized controlled trials in cancer patients treated with PD1/PD-L1 inhibitors or their combinations with chemotherapy/placebo and compared with PD1/PD-L1 inhibitors/chemotherapy/placebo were identified through comprehensive searches of multiple databases. Bayesian NMA was performed using random-effects model. Relative ranking of treatments was assessed with surface under the cumulative ranking (SUCRA) probabilities. Incidences and odds ratios of trAEs and immune-related adverse events (irAEs) of all-grade (Grade 1–5) and high-grade (Grade 3–5) were estimated.

Results: Twenty-three RCTs (14,204 patients) comparing six different strategies were included. The incidence of trAEs was lowest for PD-L1 inhibitors (all-grade: pooled incidence = 60.4%, SUCRA = 77.2%; high-grade: 6.4, 73.8%). PD-L1 inhibitors plus chemotherapy had the highest incidence of all-grade trAEs (88.6, 10.1%), while PD-1 inhibitors plus chemotherapy had the highest incidence of high-grade trAEs (8.2, 9.3%). The use of PD-1/PD-L1 inhibitors alone was associated with significant reductions on high-grade trAEs, compared with PD-1/PD-L1 inhibitors plus chemotherapy. PD-1 inhibitors had the highest incidence of irAEs (all-grade: 15.1, 9.5%; high-grade: 3.5, 16.8%). Compared with PD-L1 inhibitors, PD-1 inhibitors neither increased trAEs nor irAEs significantly. Results from sensitivity analyses were consistent.

Conclusions: Current data showed that PD-L1 inhibitors had the best safety on both trAEs and irAEs. Awareness of the comparative safety could promote further appropriate utilization of PD-1/PD-L1 inhibitors in clinical practice.

Expression of bladder cancer-associated glycans in murine tumor cell lines

The characterization of murine cell lines is of great importance in order to identify preclinical models that could resemble human diseases. Aberrant glycosylation includes the loss, excessive or novel expression of glycans and the appearance of truncated structures. MB49 and MB49-I are currently the only two murine cell lines available for the development of preclinical bladder cancer models. The glycans Lewis X (LeX), Sialyl lewis X (SLeX) and Sialyl Tn (STn) have previously been associated with aggressiveness, dissemination and poor prognosis in human bladder cancer, additionally N-glycolyl GM3 (NGcGM3) is a neo-antigen expressed in many types of tumors; however, to the best of our knowledge, its expression has not previously been assessed in this type of cancer. Taking into account the relevance of glycans in tumor biology and considering that they can act as targets of therapies and biomarkers, the present study evaluated the expression of LeX, SLeX, STn and NGcGM3 in MB49 and MB49-I cells, in different growth conditions such as monolayer cultures, three-dimensional multicellular spheroids and mouse heterotopic and orthotopic tumors. The expression of LeX was not detected in either cell line, whereas SLeX was expressed in monolayers, spheroids and orthotopic tumors of both cell lines. STn was only identified in MB49 monolayers and spheroids. There are no reports concerning the expression of NGcGM3 in human or murine bladder cancer. In our hands, MB49 and MB49-I expressed this ganglioside in all the growth conditions evaluated. The assessment of its expression in cancer cell lines and patient tumors is of great importance, considering the relevance of this ganglioside in tumor biology. The data obtained by the present study demonstrates that glycan expression may be substantially altered depending on the growth conditions, highlighting the importance of the characterization of murine cancer models. To the best of our knowledge, the present study is the first to examine the expression of cancer-associated glycans, in the two murine cell lines available for the development of preclinical studies in bladder cancer.

Prognostic significance of serum γ-glutamyltransferase in patients with advanced urothelial carcinoma

OBJECTIVES

Serum γ-glutamyltransferase (GGT) is reportedly associated with prognosis in patients with various malignancies. However, the prognostic role of GGT is unknown among patients with advanced urothelial carcinoma (aUC). This study was designed to examine the prognostic role of serum GGT in patients with aUC.

MATERIALS AND METHODS

Charts of 125 consecutive aUC patients (inoperable cT4 and/or metastasis to lymph nodes/distant organs) managed at a single cancer center between 2004 and 2016 were retrospectively reviewed. Variables collected included age, sex, body mass index, Karnofsky performance status, primary site, clinical tumor stage, lymph node/visceral metastasis, hepatic comorbidities, the presence of curative treatment before the diagnosis of aUC, white blood cell count, neutrophil-to-lymphocyte ratio, hemoglobin, albumin, lactate dehydrogenase, alkaline phosphatase, GGT, C-reactive protein, and treatments given after the diagnosis of aUC. Associations of variables with overall survival (OS) were analyzed using the Cox proportional hazard model.

RESULTS

Serum GGT was elevated (≥60 U/l) at the diagnosis of aUC in 16 patients (13%). During follow-up period (median 12.1 months), 101 patients died (2-year OS rate, 32%). Patients with elevated GGT at the diagnosis of aUC had a significantly poorer prognosis than those with normal GGT with respective 2-year OS rates of 0% and 37% (P < 0.001). On multivariate analysis, elevated GGT was a significant and independent risk factor for shorter OS (hazard ratio, HR = 2.97; P < 0.001) as were poorer Karnofsky performance status (HR = 3.47; P < 0.001), elevated lactate dehydrogenase (HR = 1.86; P = 0.033), advanced age (HR = 1.82; P = 0.013), elevated neutrophil-to-lymphocyte ratio (HR = 1.80; P = 0.015), elevated C-reactive protein (HR = 1.73; P = 0.018), the absence of systemic chemotherapy (HR = 1.71; P = 0.035), and primary site of upper urinary tract (HR = 1.71; P = 0.014) in descending order by HR. The prognostic significance of elevated GGT was also observed in a subset of 101 patients who had been diagnosed with aUC at their first presentation.

CONCLUSION

The present study for the first time demonstrated that elevated serum GGT was an independent adverse prognostic factor in aUC patients.

Immunology, Immunotherapy, and Translating Basic Science into the Clinic for Bladder Cancer

The Fourth Annual Albert Institute Bladder Cancer Care and Research Symposium was held from September 14th–16th in Houston, Texas. The symposium covered a range of topics relevant to bladder cancer, including basic science aspects of immunology and immunotherapy that inform clinical management; intravesical therapy for non-muscle invasive disease; understanding the nuances of carcinoma in situ; and optimizing patient care and outcomes following therapy. The moving landscape of bladder cancer from an industry perspective was also discussed.

In the following sections we discuss intrinsic and extrinsic factors, including the immune microenvironment and sex bias, in the context of bladder cancer; how these influence tumor development, progression, and treatment strategies; and how the interpretation of immune features in relation to molecular subtypes informs both treatment decisions and response. We conclude with a summary of key points that will need to be addressed to ensure best use of new knowledge in this area for improved clinical management of patients with bladder cancer.