EphrinB2 Inhibition and Pembrolizumab in Metastatic Urothelial Carcinoma

Advances in diagnosis and treatment of bladder cancer

Bladder cancer remains a leading cause of cancer death worldwide and is associated with substantial impacts on patient quality of life, morbidity, mortality, and cost to the healthcare system. Gross hematuria frequently precedes the diagnosis of bladder cancer. Non-muscle-invasive bladder cancer (NMIBC) is managed initially with transurethral resection of a bladder tumor (TURBT), followed by a risk stratified approach to adjuvant intravesical therapy (IVe), and is associated with an overall survival of 90%. However, cure rates remain lower for muscle invasive bladder cancer (MIBC) owing to a variety of factors. NMIBC and MIBC groupings are heterogeneous and have unique pathological and molecular characteristics. Indeed, The Cancer Genome Atlas project identified genetic drivers and luminal and basal molecular subtypes of MIBC with distinct treatment responses. For NMIBC, IVe immunotherapy (primarily BCG) is the gold standard treatment for high grade and high risk NMIBC to reduce or prevent both recurrence and progression after initial TURBT; novel trials incorporate immune checkpoint inhibitors. IVe gene therapy and combination IVe chemotherapy have recently been completed, with promising results. For localized MIBC, essential goals are improving care and reducing morbidity following cystectomy or bladder preserving strategies. In metastatic disease, advances in understanding of the genomic landscape and tumor microenvironment have led to the implementation of immune checkpoint inhibitors, targeted treatments, and antibody-drug conjugates. Defining better selection criteria to identify the patients most likely to benefit from a specific treatment is an urgent need.

Eph receptors and ephrins in cancer progression

Evidence implicating Eph receptor tyrosine kinases and their ephrin ligands (that together make up the 'Eph system') in cancer development and progression has been accumulating since the discovery of the first Eph receptor approximately 35 years ago. Advances in the past decade and a half have considerably increased the understanding of Eph receptor-ephrin signalling mechanisms in cancer and have uncovered intriguing new roles in cancer progression and drug resistance. This Review focuses mainly on these more recent developments. I provide an update on the different mechanisms of Eph receptor-ephrin-mediated cell-cell communication and cell autonomous signalling, as well as on the interplay of the Eph system with other signalling systems. I further discuss recent advances in elucidating how the Eph system controls tumour expansion, invasiveness and metastasis, supports cancer stem cells, and drives therapy resistance. In addition to functioning within cancer cells, the Eph system also mediates the reciprocal communication between cancer cells and cells of the tumour microenvironment. The involvement of the Eph system in tumour angiogenesis is well established, but recent findings also demonstrate roles in immune cells, cancer-associated fibroblasts and the extracellular matrix. Lastly, I discuss strategies under evaluation for therapeutic targeting of Eph receptors-ephrins in cancer and conclude with an outlook on promising future research directions.

Progress in systemic therapy for advanced-stage urothelial carcinoma

Despite recent advances, advanced-stage urothelial carcinoma (aUC) remains incurable, with 5-year survival rates of approximately 10%. Platinum-based chemotherapy has a major role as first-line therapy for most patients with aUC. The approval of the anti-PD-L1 antibody avelumab as maintenance therapy for patients without initial disease progression on platinum-based chemotherapy is an important development that has improved the survival outcomes of patients with this disease. Otherwise, the use of first-line immune-checkpoint inhibitors (ICIs) targeting PD-1 or PD-L1 has been restricted to patients who are ineligible for platinum-containing chemotherapy regimens. Other important developments include the FDA-accelerated approval of first-line enfortumab vedotin plus pembrolizumab for patients ineligible to receive cisplatin and the availability of FGFR inhibitors, enfortumab vedotin and sacituzumab govitecan for subsequent lines of therapy. Several research questions remain unaddressed including the lack of adequate biomarkers, how to assign priority to the different treatment options for individual patients and which agents can be effective as monotherapies. The future is promising with the emergence of modalities such as antibody-drug conjugate-like drugs, next-generation ICIs, bispecific antibodies and cellular therapies. In this Review, we summarize the evolution of systemic therapy for patients with aUC and provide insights into the unmet needs.

Precision Medicine in Urothelial Carcinoma: Current Markers to Guide Treatment and Promising Future Directions

OPINION STATEMENT

The treatment landscape for urothelial cancer has changed dramatically in the last 10 years, with the approval of several new treatments. At the same time, profiling of individual tumors has become more commonplace with widespread availability of molecular testing and immunohistochemistry. For urothelial cancer, this has led to current guidelines recommending that molecular testing be obtained in the metastatic setting, and that it be considered in the setting of locally advanced disease. Between molecular testing and immunohistochemistry testing of tumors, the only current guideline-directed application of these tests is in the identification of FGFR3 or FGFR2 alterations for use of FGFR inhibitors. While additional recurrent molecular alterations linked to the pathogenesis of urothelial cancer have been identified, the ability to successfully "drug" the pathways association with such alterations remains limited. There has been extensive research into whether expression of particular proteins might inform specific treatment approaches such as the use of PD-L1 testing to guide immune checkpoint blockade. With the integration of antibody-drug conjugates into the treatment armamentarium for urothelial cancer, ongoing research is seeking to determine whether expression of the targets of these therapies, such as Nectin 4, Trop-2, or HER2, could help to guide treatment.

Eph receptor B6 shapes a cold immune microenvironment, inhibiting anti-cancer immunity and immunotherapy response in bladder cancer

Background

The role of Eph receptors and related ephrin (EFN) ligands (as the largest family of transmembrane-bound RTKs) in immunomodulation in many types of cancer, especially bladder cancer (BLCA), is scarcely known.

Methods

A pan-cancer dataset was retrieved from The Cancer Genome Atlas (TCGA) to explore the relation between Eph receptor/EFN ligand family genes and immunomodulators and tumor-infiltrated immune cells (TIICs). Local BLCA, GSE32894, and GSE31684 cohorts were applied to validate. The IMvigor210 cohort was employed to explore the relationship between EPHB6 and immunotherapy response. Moreover, association between EPHB6 and molecular subtype was investigated to explore potential therapeutic strategies. Immunohistochemical staining of CD8 and CD68 was performed to validate the correlation between EPHB6 and TIICs.

Results

The pan-cancer analysis revealed variations in the immunological effects of Eph receptor/EFN ligand family genes across different types of cancer. EPHB6 expression negatively correlated with the expression of the majority of immunomodulators (including HLA and immune checkpoints), and CD8 T cells and macrophages in both the TCGA-BLCA and validation BLCA cohorts, shaping a cold immune microenvironment with inhibited immunity. In the IMvigor210 cohort, patients with high-EPHB6 highly correlated with a non-inflamed, low PD-L1 expression immune phenotype, and correspondingly, with less responders to immunotherapy. The high-EPHB6 group, enriched with the basal subtype, presented significantly fewer TP53 and more FGFR3 genomic alterations. Finally, a novel EPHB6-related Genes signature, with reliable and robust ability in prognosis prediction, was constructed.

Conclusions

This study comprehensively investigated the immunological effects of Eph receptor/EFN ligand family genes pan-cancer, and specially identified the immunosuppressive role of EPHB6 in BLCA. Furthermore, EPHB6 may predict the molecular subtype and prognosis of BLCA, and serve as a novel therapeutic target to improve the sensitivity of immunotherapy.

Precision Medicine to Treat Urothelial Carcinoma-The Way Forward

The treatment of urothelial carcinoma (UC) is challenging given its molecular heterogeneity and variable response to current therapies. To address this, many tools, including tumor biomarker assessment and liquid biopsies, have been developed to predict prognosis and treatment response. Approved therapeutic modalities for UC currently include chemotherapy, immune checkpoint inhibitors, receptor tyrosine kinase inhibitors, and antibody drug conjugates. Ongoing investigations to improve the treatment of UC include the search for actionable alterations and the testing of novel therapies. An important objective in recent studies has been to increase efficacy while decreasing toxicity by taking into account unique patient and tumor-related factors-an endeavor called precision medicine. The aim of this review is to highlight advancements in the treatment of UC, describe ongoing clinical trials, and identify areas for future study in the context of precision medicine.