Immune Checkpoint Blockade in Metastatic Urothelial Cancer

Integrating single-cell RNA-seq to identify fibroblast-based molecular subtypes for predicting prognosis and therapeutic response in bladder cancer

BACKGROUND

Bladder cancer (BLCA) is a highly aggressive and heterogeneous disease, posing challenges for diagnosis and treatment. Cancer immunotherapy has recently emerged as a promising option for patients with advanced and drug-resistant cancers. Fibroblasts, a significant component of the tumor microenvironment, play a crucial role in tumor progression, but their precise function in BLCA remains uncertain.

METHODS

Single-cell RNA sequencing (scRNA-seq) data for BLCA were obtained from the Gene Expression Omnibus database. The R package "Seurat" was used for processing scRNA-seq data, with uniform manifold approximation and projection (UMAP) for downscaling and cluster identification. The FindAllMarkers function identified marker genes for each cluster. Differentially expressed genes influencing overall survival (OS) of BLCA patients were identified using the limma package. Differences in clinicopathological characteristics, immune microenvironment, immune checkpoints, and chemotherapeutic drug sensitivity between high- and low-risk groups were investigated. RT-qPCR and immunohistochemistry validated the expression of prognostic genes.

RESULTS

Fibroblast marker genes identified three molecular subtypes in the testing set. A prognostic signature comprising ten genes stratified BLCA patients into high- and low-score groups. This signature was validated in one internal and two external validation sets. High-score patients exhibited increased immune cell infiltration, elevated chemokine expression, and enhanced immune checkpoint expression but had poorer OS and a reduced response to immunotherapy. Six sensitive anti-tumor drugs were identified for the high-score group. RT-qPCR and immunohistochemistry showed that CERCAM, TM4SF1, FN1, ANXA1, and LOX were highly expressed, while EMP1, HEYL, FBN1, and SLC2A3 were downregulated in BLCA.

CONCLUSION

A novel fibroblast marker gene-based signature was established, providing robust predictions of survival and immunotherapeutic response in BLCA patients.

The identification of a N6-methyladenosin-modifed immune pattern to predict immunotherapy response and survival in urothelial carcinoma

BACKGROUND

Dysregulation of the immune system and N6-methyladenosine (m6A) contribute to immune therapy resistance and cancer progression in urothelial carcinoma (UC). This study aims to identify immune-related molecules, that are m6A-modified, and that are associated with tumor progression, poor prognosis, and immunotherapy response.

METHODS

We identified prognostic immune genes (PIGs) using Cox analysis and random survival forest variable hunting algorithm (RSF-VH) on immune genes retrieved from the Immunology Database and Analysis Portal database (ImmPort). The RM2Target database and MeRIP-seq analysis, combined with a hypergeometric test, assessed m6A methylation in these PIGs. We analyzed the correlation between the immune pattern and prognosis, as well as their association with clinical factors in multiple datasets. Moreover, we explored the interplay between immune patterns, tumor immune cell infiltration, and m6A regulators.

RESULTS

28 PIGs were identified, of which the 10 most significant were termed methylated prognostic immune genes (MPIGs). These MPIGs were used to create an immune pattern score. Kaplan-Meier and Cox analyses indicated this pattern as an independent risk factor for UC. We observed significant associations between the immune pattern, tumor progression, and immune cell infiltration. Differential expression analysis showed correlations with m6A regulators expression. This immune pattern proved effective in predicting immunotherapy response in UC in real-world settings.

CONCLUSION

The study identified a m6A-modified immune pattern in UC, offering prognostic and therapeutic response predictions. This emphasizes that immune genes may influence tumor immune status and progression through m6A modifications.

A Phase II Study of Durvalumab for Bacillus Calmette-Guerin (BCG) Unresponsive Urothelial Carcinoma In Situ of the Bladder

PURPOSE

Immune checkpoint blockade holds promise for treating bacillus Calmette-Guerin (BCG)-unresponsive non-muscle-invasive bladder cancer (NMIBC). In this phase II study, we investigated the safety and efficacy of durvalumab, a human IgG1 monoclonal antibody, against BCG-unresponsive carcinoma in situ (CIS).

PATIENTS AND METHODS

Patients with BCG-unresponsive CIS-containing NMIBC received durvalumab IV at 1,500 mg every 4 weeks for up to 12 months. The primary endpoint was complete response (CR) rate at month 6, defined by negative cystoscopy, urine cytology, and absence of high-grade recurrence on bladder mapping biopsy. The null hypothesis specified a CR rate of 18% and alternative hypothesis of 40%. According to the Simon two-stage design, if ≤3/13 patients achieved CR during stage 1, the trial is stopped due to futility.

RESULTS

Between March 8, 2017, and January 24, 2020, 17 patients were accrued whereas 4 withdrew from study treatment after bladder biopsy at month 3 was positive for CIS. Two of 17 (12%) achieved a CR at month 6, with duration of response of 10 and 18 months, respectively. A single grade 3 lipase elevation was attributed to durvalumab, and immune-related adverse events were observed in 7/17 (41%) patients. Only 1/17 patients had high programmed death-ligand 1 expression pretreatment. On RNA sequencing, complement activation genes were elevated posttreatment, along with enrichment of tumor-associated macrophage signature.

CONCLUSIONS

Durvalumab monotherapy conferred minimal efficacy in treating BCG-unresponsive CIS of the bladder, with 6-month CR of 12%. Complement activation is a potential mechanism behind treatment resistance.

IGFBP7 and the Tumor Immune Landscape: A Novel Target for Immunotherapy in Bladder Cancer

Insulin-like growth factor binding protein-7 (IGFBP7) was recently reported to be a ligand of CD93, a potential target to normalize vasculature and attenuate immunotherapy. However, its role in the tumor microenvironment (TME) and immunotherapy response of bladder cancer (BLCA) remains unclear. We comprehensively evaluated the correlation between IGFBP7 and multiple immunological characteristics of BLCA across The Cancer Genome Atlas (TCGA) and two external cohorts. Importantly, the response of IGFBP7-grouped BLCA patients to immunotherapy was predicted and validated by five real-word immunotherapy cohorts. Finally, we developed an IGFBP7-based immune risk model validated by five independent cohorts. IGFBP7 modulated the TME across pan-caners. In BLCA, high expression of IGFBP7 was correlated with more aggressive clinical features. IGFBP7 was positively associated with immunomodulators and promoted tumor-infiltrating lymphocyte trafficking into the tumor microenvironment. However, T cells recognition and tumor cell killing were lower in the high-IGFBP7 group. In addition, high expression of IGFBP7 displayed lower enrichment scores for most pro-immunotherapy pathways. Clinical data from IMvigor210 and GSE176307 indicated that IGFBP7 negatively correlated with the BLCA immunotherapy response. The same trend was also observed in a renal cell carcinoma (RCC) cohort and two melanoma cohorts. Notably, urothelial and luminal differentiation were less frequently observed in the high-IGFBP7 group, while neuroendocrine differentiation was more frequently observed. Mechanistically, high IGFBP7 was associated with an enriched hypoxia pathway and higher expression of key genes in ERBB therapy and antiangiogenic therapy. Furthermore, our IGFBP7-based immune risk model was able to predict the prognosis and response to immunotherapy with good accuracy (5-year AUC = 0.734). Overall, IGFBP7 plays a critical role in the immunoregulation and TME of BLCA and may serve as a novel potential target for combination treatment with immunotherapy for BLCA.

Using oncolytic viruses to ignite the tumour immune microenvironment in bladder cancer

The advent of immune checkpoint inhibition (ICI) has transformed the treatment paradigm for bladder cancer. However, despite the success of ICI in other tumour types, the majority of ICI-treated patients with bladder cancer failed to respond. The lack of efficacy in some patients could be attributed to a paucity of pre-existing immune reactive cells within the tumour immune microenvironment, which limits the beneficial effects of ICI. In this setting, strategies to attract lymphocytes before implementation of ICI could be helpful. Oncolytic virotherapy is thought to induce the release of damage-associated molecular patterns, eliciting a pro-inflammatory cytokine cascade and stimulating the activation of the innate immune system. Concurrently, oncolytic virotherapy-induced oncolysis leads to further release of neoantigens and subsequent epitope spreading, culminating in a robust, tumour-specific adaptive immune response. Combination therapy using oncolytic virotherapy with ICI has proven successful in a number of preclinical studies and is beginning to enter clinical trials for the treatment of both non-muscle-invasive and muscle-invasive bladder cancer. In this context, understanding of the mechanisms underpinning oncolytic virotherapy and its potential synergism with ICI will enable clinicians to effectively deploy oncolytic virotherapy, either as monotherapy or as combination therapy in the different clinical stages of bladder cancer.

Tumor Microenvironment Analysis Identified Subtypes Associated With the Prognosis and the Tumor Response to Immunotherapy in Bladder Cancer

Background: The efficiency of immune checkpoint inhibitors (ICIs) in bladder cancer (BLCA) treatment has been widely validated; however, the tumor response to ICIs was generally low. It is critical and urgent to find biomarkers that can predict tumor response to ICIs. The tumor microenvironment (TME), which may play important roles to either dampen or enhance immune responses, has been widely concerned. Methods: The cancer genome atlas BLCA (TCGA-BLCA) cohort (n = 400) was used in this study. Based on the proportions of 22 types of immune cells calculated by CIBERSORT, TME was classified by K-means Clustering and differentially expressed genes (DEGs) were determined. Based on DEGs, patients were classified into three groups, and cluster signature genes were identified after reducing redundant genes. Then TMEscore was calculated based on cluster signature genes, and the samples were classified to two subtypes. We performed somatic mutation and copy number variation analysis to identify the genetic characteristics of the two subtypes. Correlation analysis was performed to explore the correlation between TMEscore and the tumor response to ICIs as well as the prognosis of BLCA. Results: According to the proportions of immune cells, two TME clusters were determined, and 1,144 DEGs and 138 cluster signature genes were identified. Based on cluster signature genes, samples were classified into TMEscore-high (n = 199) and TMEscore-low (n = 201) subtypes. Survival analysis showed patients with TMEscore-high phenotype had better prognosis. Among the 45 differentially expressed micro-RNAs (miRNAs) and 1,033 differentially expressed messenger RNAs (mRNAs) between the two subtypes, 16 miRNAs and 287 mRNAs had statistically significant impact on the prognosis of BLCA. Furthermore, there were 94 genes with significant differences between the two subtypes, and they were enriched in RTK-RAS, NOTCH, WNT, Hippo, and PI3K pathways. The Tumor Immune Dysfunction and Exclusion (TIDE) score of TMEscore-high BLCA was statistically lower than that of TMEscore-low BLCA. Receiver operating characteristic (ROC) curve analysis showed that the area under the curve (AUC) of TMEscore and tumor mutation burden (TMB) is 0.6918 and 0.5374, respectively. Conclusion: We developed a method to classify BLCA patients to two TME subtypes, TMEscore-high and TMEscore-low, and we found TMEscore-high subtype of BLCA had a good prognosis and a good response to ICIs.

Immunotherapy in Bacillus Calmette-Guerin (BCG) unresponsive nonmuscle invasive bladder cancer

PURPOSE OF REVIEW

A number of promising therapies for Bacillus Calmette-Guerin (BCG) unresponsive nonmuscle invasive bladder cancer (NMIBC) are in the pipeline. In this review, we discuss the history of immunotherapy for the treatment of NMIBC and future developments, focusing on novel intravesical treatments.

RECENT FINDINGS

The term BCG unresponsive NMIBC encompasses patients with both BCG refractory and BCG relapsing disease. This definition was adopted to standardize inclusion criteria for patients enrolling in clinical trials in this setting. A host of intravesical immuno-oncologic therapies that include gene therapies, oncolytic viruses, cell surface molecule delivered immunotoxins, and cytokine driven agonism of cellular immunity, are in various phases of the drug development pipeline. In addition, pembrolizumab, an immune-checkpoint inhibitor, has recently been approved as a treatment option for BCG unresponsive NMIBC.

SUMMARY

Patients with BCG unresponsive disease face many difficulties. Although radical cystectomy is the most effective treatment option for these patients, it is associated with significant morbidity, difficult recovery challenges, and refusal by many patients. Cancer immunotherapies may provide bladder sparing options for some patients who develop BCG unresponsive disease.

Cabozantinib in Combination with Immunotherapy for Advanced Renal Cell Carcinoma and Urothelial Carcinoma: Rationale and Clinical Evidence

The treatment landscape for metastatic renal cell carcinoma (mRCC) and urothelial carcinoma (mUC) has evolved rapidly in recent years with the approval of several checkpoint inhibitors. Despite these advances, survival rates for metastatic disease remain poor, and additional strategies will be needed to improve the efficacy of checkpoint inhibitors. Combining anti-VEGF/VEGFR agents with checkpoint inhibitors has emerged as a potential strategy to advance the immunotherapy paradigm, because VEGF inhibitors have immunomodulatory potential. Cabozantinib is a tyrosine kinase inhibitor (TKI) whose targets include MET, AXL, and VEGFR2. Cabozantinib has a unique immunomodulatory profile and has demonstrated clinical efficacy as a monotherapy in mRCC and mUC, making it a potentially suitable partner for checkpoint inhibitor therapy. In this review, we summarize the current status of immunotherapy for mRCC and mUC and discuss the development of immunotherapy-TKI combinations, with a focus on cabozantinib. We discuss the rationale for such combinations based on our growing understanding of the tumor microenvironment, and we review in detail the preclinical and clinical studies supporting their use.

Evaluation of Survival Outcomes With Trimodal Therapy as Primary Therapy for Non-organ-confined Bladder Cancer

Background: Currently, the diagnosis of non-organ-confined bladder cancer (NOCBCa) has a very poor prognosis. For patients with NOCBCa, treatments such as radical cystectomy (RC) and systemic chemotherapy have shown survival benefits. However, the relative survival benefits of trimodal therapy (TMT) are unclear.

Methods: Patients diagnosed with NOCBCa (cT4bN0M0, cTxN1-3M0, or TxNxM1) were identified in the Surveillance, Epidemiology, and End Results (SEER) database (2004–2015). Patients were grouped based on their definitive treatment for bladder cancer (RC or TMT with maximal transurethral resection, chemotherapy, or radiotherapy). All-cause mortality (ACM) and bladder cancer-specific mortality (BCSM) were assessed by Cox proportional hazard regression and competitive risk models.

Results: A total of 2,988 patients met the inclusion criteria and were treated with RC (83.5%) or TMT (16.5%). Patients who underwent TMT had higher 5-year ACM (91.3%) and BCSM (88.8%) results compared to patients who underwent RC (82.6 and 75.0%, respectively) (P < 0.001). Adjusted hazard rate (AHR) analysis showed that TMT was associated with higher ACM (AHR: 1.33, 95% CI: 1.15–1.54, P < 0.001) and higher BCSM (AHR: 1.32, 95% CI: 1.13–1.54, P = 0.001). Subgroup analysis revealed not statistically significant between RC and TMT among patients aged ≥80 years (P > 0.05).

Conclusions: Compared with TMT, RC is associated with a significant reduction in ACM and BCSM. However, the risks and survival benefits of RC should be weighed, especially in older patients, and our results further suggest that there may be no difference in the prognosis of RC and TMT in patients ≥80 years of age. These results are preliminary and emphasize the need for randomized controlled trials to compare TMT and RC.

Update on the Treatment of Metastatic Urothelial Carcinoma

Platinum-based combination chemotherapy has been the standard of care in the first-line treatment of metastatic urothelial carcinoma (mUC). Treatment of metastatic disease following progression on platinum-based regimens has evolved significantly in the last few years. Clinical trials are currently ongoing to determine how best to use and sequence these treatments. In this minireview, we will review current first-line treatment options in both cisplatin fit and cisplatin unfit patients and advances in first- and second-line treatments including chemotherapy and immunotherapy. This review reports key findings from the clinical trials especially highlighting the importance of PD-1 and PD-L1 inhibitors in the treatment of bladder/urothelial carcinomas.

Multidisciplinary Management of Muscle-Invasive Bladder Cancer: Current Challenges and Future Directions

The treatment of muscle-invasive bladder cancer (MIBC) is complex and requires a multidisciplinary collaboration among surgery, radiation, and medical oncology. Although neoadjuvant chemotherapy (NAC) followed by radical cystectomy (RC) and lymph node dissection has been considered the standard treatment for MIBC, many patients are unfit for surgery or cisplatin-ineligible, and considerations for bladder-preservation strategies not only are increasingly recognized as optimal treatment alternatives, but also should feature in the range of management options presented to patients at the time of diagnosis. Apart from chemotherapy, immunotherapy has also been used with success in locally advanced and metastatic bladder cancer and is moving into the MIBC space. Prospective studies addressing trends in management that span systemic, surgical, and radiation options for patients are discussed in this article.

Role of Radical Cystectomy in Non-Organ Confined Bladder Cancer: A Systematic Review

Background:

Currently, a diagnosis of non-organ confined bladder cancer (NOCBCa) confers a grave prognosis. The mainstay of treatment consists of systemic chemotherapy. However, it must be recognized that NOCBCa is a heterogeneous disease state with important clinical distinctions. While surgical extirpation has traditionally been regarded as overly aggressive for all NOCBCa patients, its utility as part of a multimodal treatment strategy in various clinical scenarios has not been thoroughly investigated.

Objective:

To perform a review of the literature regarding the role of radical cystectomy and pelvic lymph node dissection (RC-LND) in the setting of NOCBCa.

Methods:

Medline, and Pubmed electronic database were queried for English language articles from January 1990 to Nov 2016 on RC-LND for cT4, lymph node positive, and metastatic urothelial cancer. NOCBCa was separated into four distinct clinical scenarios: 1. Locally advanced/unresectable disease (cT4bN0M0); 2. Occult pelvic nodal disease (pN+) (cTxN0M0 and pTxN1-3Mx); 3. Clinical node positive disease (cN+) (cTxN1-3M0); and 4. Distant metastatic disease (TxNxM1). Evidence for the role of RC-LND in each of these clinical scenarios was summarized.

Results:

cT4b may be more effectively treated by presurgical chemotherapy (PSC) than other forms of NOCBCa. Although clinical response predicted improved survival, surgical factors, such as surgical margin status may also play a role in determining outcomes. In well selected patients, 5-year CSS may reach 60% after consolidative RC-LND. Survival in patients found to have pathologic nodal metastases without PSC was dictated not only by the histologically verified metastatic nodal disease burden, but also by the meticulousness of the lymph node dissection. In these patients, adjuvant chemotherapy may improve survival. On the other hand, in patients undergoing RC-LND after PSC, pathologic complete response (pCR) was the strongest predictor of improved CSS. The results of population based studies have suggested a therapeutic role by consolidative RC-LND in both patients with cN+ and metastatic BCa (mBCa). For the cN+ population, 5-year OS was 31% in patients undergoing RC-LND after PSC vs. 14% in those receiving chemotherapy alone. Similarly, consolidative intensive local therapy improved OS by approximately 5 months in patients with mBCa. Metastasectomy has also been shown to be effective in small retrospective series and may especially be useful in patients with solitary pulmonary lesions.

Conclusions:

Extirpative treatment of the primary tumor may be an important step in the management of de novo NOCBCa. The current retrospective and population based studies have demonstrated improved survival outcomes in patients with NOCBCa following RC-LND, especially in those with favorable response to PSC. With the advent of minimally invasive surgery and the enhanced post-surgical recovery protocols, RC-LND has not only been demonstrated to be feasible, but also tolerable in the setting of advanced BCa. Well designed, prospective trials are needed to definitively assess the value of surgical extirpation for NOCBCa patients.