Results of the Southwest Oncology Group phase II evaluation (study S0031) of ZD1839 for advanced transitional cell carcinoma of the urothelium

Discovering Therapeutic Protein Targets for Bladder Cancer Using Proteomic Data Analysis

BACKGROUND

Bladder cancer accounts for almost 54% of urinary system cancer and is the second most frequent cause of death in genitourinary malignancies after prostate cancer. About 70% of bladder tumors are non-muscle-invasive, and the rest are muscle-invasive. Recurrence of the tumor is the common feature of bladder cancer. Chemotherapy is a conventional treatment for MIBC, but it cannot improve the survival rate of these patients sufficiently. Therefore, researchers must develop new therapies. Antibody-based therapy is one of the most important strategies for the treatment of solid tumors. Selecting a suitable target is the most critical step for this strategy.

OBJECTIVE

The aim of this study is to detect therapeutic cell surface antigen targets in bladder cancer using data obtained by proteomic studies.

METHODS

Isobaric tag for relative and absolute quantitation (iTRAQ) analysis had identified 131 overexpressed proteins in baldder cancer tissue and reverse-phase proteomic array (RPPA) analysis had been done for 343 tumor tissues and 208 antibodies. All identified proteins from two studies (131+208 proteins) were collected and duplicates were removed (331 unique proteins). Gene ontology study was performed using gene ontology (GO) and protein analysis through evolutionary relationships (PANTHER) databases. The Human Protein Atlas database was used to search the protein class and subcellular location of membrane proteins obtained from the PANTHER analysis.

RESULTS

Membrane proteins that could be suitable therapeutic targets for bladder cancer were selected. These included: Epidermal growth factor receptor (EGFR), Her2, Kinase insert domain receptor (KDR), Heat shock protein 60 (HSP60), HSP90, Transferrin receptor (TFRC), Activin A Receptor Like Type 1 (ACVRL1), and cadherin 2 (CDH2). Monoclonal antibodies against these proteins or their inhibitors were used for the treatment of different cancers in preclinical and clinical trials.

CONCLUSION

These monoclonal antibodies and inhibitor molecules and also their combination can be used for the treatment of bladder cancer.

Developing Precision Medicine for Bladder Cancer

The hallmark of precision medicine involves tailoring the treatment to the patient and/or tumor-specific biomarkers. Candidate biomarkers in bladder cancer are abundant, but few have been validated in clinical practice. Significant obstacles to precision medicine in bladder cancer include the limited predictive value of candidate biomarkers, lack of standardization in biomarker assessment, heterogeneity in biomarker expression and function, and limited insight into the biologic factors that influence biomarker expression and predictive capacity. This review summarizes key biomarkers explored in bladder cancer and outlines innovative trial designs to approach these obstacles.

Novel Tyrosine Kinase Targets in Urothelial Carcinoma

Urothelial carcinoma represents one of the most prevalent types of cancer worldwide, and its incidence is expected to grow. Although the treatment of the advanced disease was based on chemotherapy for decades, the developments of different therapies, such as immune checkpoint inhibitors, antibody drug conjugates and tyrosine kinase inhibitors, are revolutionizing the therapeutic landscape of this tumor. This development coincides with the increasing knowledge of the pathogenesis and genetic alterations in urothelial carcinoma, from the non-muscle invasive setting to the metastatic one. The purpose of this article is to provide a comprehensive review of the different tyrosine kinase targets and their roles in the therapeutic scene of urothelial carcinoma.

The Clinical Kinase Index: A Method to Prioritize Understudied Kinases as Drug Targets for the Treatment of Cancer

The approval of the first kinase inhibitor, Gleevec, ushered in a paradigm shift for oncological treatment-the use of genomic data for targeted, efficacious therapies. Since then, over 48 additional small-molecule kinase inhibitors have been approved, solidifying the case for kinases as a highly druggable and attractive target class. Despite the role deregulated kinase activity plays in cancer, only 8% of the kinome has been effectively "drugged." Moreover, 24% of the 634 human kinases are understudied. We have developed a comprehensive scoring system that utilizes differential gene expression, pathological parameters, overall survival, and mutational hotspot analysis to rank and prioritize clinically relevant kinases across 17 solid tumor cancers from The Cancer Genome Atlas. We have developed the clinical kinase index (CKI) app (http://cki.ccs.miami.edu) to facilitate interactive analysis of all kinases in each cancer. Collectively, we report that understudied kinases have potential clinical value as biomarkers or drug targets that warrant further study.

EGFR activity addiction facilitates anti-ERBB based combination treatment of squamous bladder cancer

Recent findings suggested a benefit of anti-EGFR therapy for basal-like muscle-invasive bladder cancer (MIBC). However, the impact on bladder cancer with substantial squamous differentiation (Sq-BLCA) and especially pure squamous cell carcinoma (SCC) remains unknown. Therefore, we comprehensively characterized pure and mixed Sq-BLCA (n = 125) on genetic and protein expression level, and performed functional pathway and drug-response analyses with cell line models and isolated primary SCC (p-SCC) cells of the human urinary bladder. We identified abundant EGFR expression in 95% of Sq-BLCA without evidence for activating EGFR mutations. Both SCaBER and p-SCC cells were sensitive to EGFR tyrosine kinase inhibitors (TKIs: erlotinib and gefitinib). Combined treatment with anti-EGFR TKIs and varying chemotherapeutics led to a concentration-dependent synergism in SCC cells according to the Chou-Talalay method. In addition, the siRNA knockdown of EGFR impaired SCaBER viability suggesting a putative "Achilles heel" of Sq-BLCA. The observed effects seem Sq-BLCA-specific since non-basal urothelial cancer cells were characterized by poor TKI sensitivity associated with a short-term feedback response potentially attenuating anti-tumor activity. Hence, our findings give further insights into a crucial, Sq-BLCA-specific role of the ERBB signaling pathway proposing improved effectiveness of anti-EGFR based regimens in combination with chemotherapeutics in squamous bladder cancers with wild-type EGFR-overexpression.

Evolution of Urothelial Bladder Cancer in the Context of Molecular Classifications

Bladder cancer is a heterogeneous disease that is not depicted by current classification systems. It was originally classified into non-muscle invasive and muscle invasive. However, clinically and genetically variable tumors are summarized within both classes. A definition of three groups may better account for the divergence in prognosis and probably also choice of treatment. The first group represents mostly non-invasive tumors that reoccur but do not progress. Contrarily, the second group represent non-muscle invasive tumors that likely progress to the third group, the muscle invasive tumors. High throughput tumor profiling improved our understanding of the biology of bladder cancer. It allows the identification of molecular subtypes, at least three for non-muscle invasive bladder cancer (Class I, Class II and Class III) and six for muscle-invasive bladder cancer (luminal papillary, luminal non-specified, luminal unstable, stroma-rich, basal/squamous and neuroendocrine-like) with distinct clinical and molecular phenotypes. Molecular subtypes can be potentially used to predict the response to treatment (e.g., neoadjuvant chemotherapy and immune checkpoint inhibitors). Moreover, they may allow to characterize the evolution of bladder cancer through different pathways. However, to move towards precision medicine, the understanding of the biological meaning of these molecular subtypes and differences in the composition of cell subpopulations will be mandatory.

Systemic treatment for advanced urothelial cancer: an update on recent clinical trials and current treatment options

After cisplatin-based chemotherapy became the standard treatment for metastatic urothelial cancer (mUC), very little progress has been made in the treatment landscape of this condition until recently. With increased knowledge about the molecular biology of mUC and advances in the field of cancer immunobiology, there has been an explosion in the number of clinical trials for mUC, and systemic treatment of mUC is rapidly changing. Despite the availability of several novel therapeutic agents, cisplatin-based cytotoxic chemotherapy remains the standard, first-line treatment option. Immune checkpoint inhibitors (ICIs), including programmed death-1 and programmed death ligand-1 inhibitors, are preferred second-line treatment options that are also used in first-line cisplatin-ineligible settings. For patients with actionable fibroblast growth factor receptor 2 (FGFR2) or FGFR3 genomic alterations, erdafitinib can be considered after platinum-based treatment. Enfortumab vedotin, a monoclonal antibody targeting nectin-4 conjugated to monomethyl auristatin E, has been approved for patients who do not respond to both cytotoxic chemotherapy and ICIs. In this review, we address the clinical trial data that have established the current standard treatments and ongoing clinical trials of various agents with different mechanisms as well as provide a brief overview of current practice guidelines and recommendations in patients with mUC.

Precision oncology in urothelial cancer

Genomics-driven, precision medicine has been adopted in virtually every tumour type and underlies the significant advances in cancer management to date. The paradigm shift from the indiscriminate use of chemotherapeutics, to strategies that harness our mechanistic knowledge of cancer biology has led to profound clinical benefit for patients, and will continue to mould present and future treatment approaches. In the realm of urothelial cancer, the present status of precision medicine includes a rich landscape that encompasses molecularly-matched therapy, predictive biomarkers that could help inform response to chemotherapy and immunotherapy, as well as novel strategies such as antibody drug conjugates that exploit the use of target proteins for enhanced tumour killing. Here, we present an overview on these clinically-impactful discoveries in urothelial cancer, discuss the limitations and challenges in the implementation of precision oncology, and offer our vision for its future.

Naturally-Occurring Invasive Urothelial Carcinoma in Dogs, a Unique Model to Drive Advances in Managing Muscle Invasive Bladder Cancer in Humans

There is a great need to improve the outlook for people facing urinary bladder cancer, especially for patients with invasive urothelial carcinoma (InvUC) which is lethal in 50% of cases. Improved outcomes for patients with InvUC could come from advances on several fronts including emerging immunotherapies, targeted therapies, and new drug combinations; selection of patients most likely to respond to a given treatment based on molecular subtypes, immune signatures, and other characteristics; and prevention, early detection, and early intervention. Progress on all of these fronts will require clinically relevant animal models for translational research. The animal model(s) should possess key features that drive success or failure of cancer drugs in humans including tumor heterogeneity, genetic-epigenetic crosstalk, immune cell responsiveness, invasive and metastatic behavior, and molecular subtypes (e.g., luminal, basal). Experimental animal models, while essential in bladder cancer research, do not possess these collective features to accurately predict outcomes in humans. These key features, however, are present in naturally-occurring InvUC in pet dogs. Canine InvUC closely mimics muscle-invasive bladder cancer in humans in cellular and molecular features, molecular subtypes, immune response patterns, biological behavior (sites and frequency of metastasis), and response to therapy. Thus, dogs can offer a highly relevant animal model to complement other models in research for new therapies for bladder cancer. Clinical treatment trials in pet dogs with InvUC are considered a win-win-win scenario; the individual dog benefits from effective treatment, the results are expected to help other dogs, and the findings are expected to translate to better treatment outcomes in humans. In addition, the high breed-associated risk for InvUC in dogs (e.g., 20-fold increased risk in Scottish Terriers) offers an unparalleled opportunity to test new strategies in primary prevention, early detection, and early intervention. This review will provide an overview of canine InvUC, summarize the similarities (and differences) between canine and human InvUC, and provide evidence for the expanding value of this canine model in bladder cancer research.

Management of metastatic bladder cancer

Important advances in the understanding of the biology and mechanisms of tumor progression of urothelial carcinoma (UC) have been achieved over the past decade. The treatment landscape for advanced-stage, unresectable or metastatic UC has shifted dramatically over a short period of time, with 6 new therapeutic agents available for clinical use. The use of traditional chemotherapy and new immune checkpoints inhibitors (ICIs) directed at programmed cell-death protein 1 (PD-1) or its ligand has led to unprecedented survival benefits in selected patients with metastatic UC. Data show that anti-PD-1 ICIs are not only improving long-term clinical benefit, but also quality of life for patients in the second-line setting. In the front-line setting, regulatory agencies have restricted the indications of atezolizumab and pembrolizumab (both ICIs) to patients with PD-L1positivity with advanced UC and who are platinum-ineligible. Very recently, erdafitinib, a pan-FGFR inhibitor, has been granted accelerated approval by FDA for platinum-pretreated advanced metastatic UC with susceptible FGFR3 or FGFR2 genetic alterations. Enfortumab vedotin, an antibody-drug conjugate, have been granted breakthrough designation by the FDA for the treatment of metastatic UC. Here we review the clinical trial data that have established standard-of-care treatment for advanced-stage UC. In addition, mechanisms of resistance and biomarkers of response to platinum-based chemotherapies and immunotherapies are also discussed, along with the clinical benefits and limitations of these therapies.

Targeted therapies in urothelial bladder cancer: a disappointing past preceding a bright future?

Bladder cancer (BC) is the most frequent cancer affecting the urinary tract. With the growing era of targeted therapies around the 2000s, many trials evaluated the efficacy of targeted therapy in advanced BC. However, no approval was given yet to any form of targeted therapy when it comes to BC. The aim of this paper was to report the most pivotal trials that evaluated different families of targeted therapy in the treatment of BC, according to their biomarkers (FGFR3, EGFR, HER2, VEGF and PI3K/AKT/mTOR). The ongoing trials testing targeted therapies in advanced BC were then summarized. Finally, the different immunotherapies approved for this disease and their potential combination with targeted therapy were addressed.

Contemporary best practice in the management of urothelial carcinomas of the renal pelvis and ureter

Upper tract urothelial carcinoma (UTUC) accounts for 5% of urothelial carcinomas (UCs), the estimated annual incidence being 1-2 cases per 100,000 inhabitants. Similarly to bladder UC, divergent differentiations and histologic variants confer an adverse risk factor in comparison with pure UTUC. Molecular and genomic characterization studies on UTUC have shown changes occurring at differing frequencies from bladder cancer, with unique molecular and clinical subtypes, potentially with different responses to treatment. Systemic chemotherapy is the standard approach for patients with inoperable locally advanced or metastatic UCs. Although initial response rates are high, the median survival with combination chemotherapy is about 15 months. In first-line chemotherapy several cisplatin-based regimens have been proposed. For patients with advanced UC who progress to first-line treatment, the only product licensed in Europe is vinflunine, a third-generation, semisynthetic, vinca alkaloid. Better response rates (15-60%), with higher toxicity rates and no overall survival (OS) benefit, are generally achieved in multidrug combinations, which often include taxanes and gemcitabine. The US FDA has recently approved five agents targeting the programmed death-1 and programmed death ligand-1 pathway as a second-line therapy in patients with locally advanced or metastatic UC with disease progression during or following platinum-containing chemotherapy. Potential therapeutic targets are present in 69% of tumours analyzed. Specific molecular alterations include those involved in the RTK/Ras/PI(3)K, cell-cycle regulation and chromatin-remodeling pathways, many of them have either targeted therapies approved or under investigation. Angiogenic agents, anti-epidermal growth factor receptor therapy, phosphoinositide 3-kinase (PI3K) and mammalian target of rapamycin (mTOR) pathway inhibitors and immunotherapeutic drugs are being successfully investigated.

Evolution of randomized controlled trials and surrogacy of progression-free survival in advanced/metastatic urothelial cancer

BACKGROUND

Clinical trials in advanced/metastatic urothelial cancer have been difficult to perform. We review the current characteristics of randomized controlled trials (RCTs) and evaluate whether PFS could be a potential surrogate endpoint for overall survival (OS) in advanced/metastatic urothelial cancer.

METHODS

We identified trials by a systematic review of Medline, Embase, and the Cochrane Central Register of Controlled Trials from inception to April 2017. We included RCTs of patients with locally advanced/metastatic urothelial cancer that involved systemic therapy as an intervention, and those with reported hazards ratios (HRs) and corresponding 95% confidence intervals (CIs) for both OS and PFS, or provided Kaplan-Meier curves from which HRs and 95% CI could be calculated. The correlation coefficient between log of HRs for OS and PFS was calculated using linear regression weighted by sample size.

RESULTS

Forty eight trials that enrolled 7019 patients were included in the review and 24 RCTs were included in the surrogacy analysis. 27(56.3%) of identified 48 RCTs were phase II trials, and the median sample size was 107(range, 30-626) for all RCTs. The correlation coefficient between log HR for PFS and log HR for OS was 0.79 (95% CI, 0.58-0.91). The correlation coefficient increased to 0.87 (95% CI, 0.72-0.94) after excluding the only trial with immune checkpoint inhibitor. Multiple sensitivity analyses did not change the results..aph."/> CONCLUSIONS: PFS is strongly correlated with OS in trials of advanced/metastatic urothelial cancer assessing the treatment benefit of new drugs And PFS warrants further exploration as a surrogate endpoint in clinical trial datasets.

A Gene Expression Signature Predicts Bladder Cancer Cell Line Sensitivity to EGFR Inhibition

Background:

Bladder cancer remains a cancer type in need of novel and alternative therapies. While multiple inhibitors of EGFR have been evaluated for efficacy in bladder cancer, the results have largely been disappointing with few patients responding to these therapies. Yet, there is a subset of patients that positively responds to EGFR inhibition with tumor shrinkage, indicating it is an effective treatment for a targeted set of bladder tumors.

Objective:

To derive a gene expression signature capable of predicting the response to EGFR inhibition in bladder cancer cell lines.

Methods:

he response to cetuximab for 68 colorectal cancer patients was used as training data to generate a gene expression signature. We applied this signature to bladder cancer cell lines and predictions were compared to the responses to seven EGFR inhibitors.

Results:

A novel 67-gene signature derived from colorectal cancer was able to significantly identify bladder cancer cell lines by their response to several EGFR inhibitors.

Conclusions:

The 67-gene signature can determine bladder cancer cell line sensitivity to EGFR inhibition. This work demonstrates a preclinical strategy to identify bladder cancer cell lines for EGFR-targeted therapy.

Cyclooxygenase inhibitors potentiate receptor tyrosine kinase therapies in bladder cancer cells in vitro

Purpose

Receptor tyrosine kinase inhibitors (RTKIs) are used as targeted therapies for patients diagnosed with cancer with highly expressed receptor tyrosine kinases (RTKs), including the platelet-derived growth factor receptor (PDGFR) and c-Kit receptor. Resistance to targeted therapies is partially due to the activation of alternative pro-survival signaling pathways, including cyclooxygenase (COX)-2. In this study, we validated the effects of two RTKIs, axitinib and AB1010, in combination with COX inhibitors on the V-akt murine thymoma oncogene homolog 1 (Akt) and COX-2 signaling pathways in bladder cancer cells.

Methods

The expression of several RTKs and their downstream signaling targets was analyzed by Western blot (WB) analysis in human and canine bladder transitional cell carcinoma (TCC) cell lines. The effects of RTKIs and COX inhibitors in bladder TCC cells were assessed by MTS for cell viability, by Caspase-3/7 and Annexin V assay for apoptosis, by WB analysis for detection of COX-2 and Akt signaling pathways, and by enzyme-linked immunosorbent assay for detection of prostaglandin E2 (PGE₂) levels.

Results

All tested TCC cells expressed the c-Kit and PDGFRα receptors, except human 5637 cells that had low RTKs expression. In addition, all tested cells expressed COX-1, COX-2, Akt, extracellular signal regulated kinases 1/2, and nuclear factor kappa-light-chain-enhance of activated B cells proteins, except human UM-UC-3 cells, where no COX-2 expression was detected by WB analysis. Both RTKIs inhibited cell viability and increased apoptosis in a dose-dependent manner in tested bladder TCC cells, which positively correlated with their expression levels of the PDGFRα and c-Kit receptors. RTKIs increased the expression of COX-2 in h-5637 and K9TCC#1Lillie cells. Co-treatment of indomethacin inhibited AB1010-induced COX-2 expression leading to an additive effect in inhibition of cell viability and PGE₂ production in tested TCC cells.

Conclusion

Co-treatment of RTKIs with indomethacin inhibited cell viability and AB1010-induced COX-2 expression resulting in decreased PGE₂ production in tested TCC cells. Thus, COX inhibition may further potentiate RTKIs therapies in bladder cancer.

Naturally-Occurring Canine Invasive Urothelial Carcinoma: A Model for Emerging Therapies

The development of targeted therapies and the resurgence of immunotherapy offer enormous potential to dramatically improve the outlook for patients with invasive urothelial carcinoma (InvUC). Optimization of these therapies, however, is crucial as only a minority of patients achieve dramatic remission, and toxicities are common. With the complexities of the therapies, and the growing list of possible drug combinations to test, highly relevant animal models are needed to assess and select the most promising approaches to carry forward into human trials. The animal model(s) should possess key features that dictate success or failure of cancer drugs in humans including tumor heterogeneity, genetic-epigenetic crosstalk, immune cell responsiveness, invasive and metastatic behavior, and molecular subtypes (e.g., luminal, basal). While it may not be possible to create these collective features in experimental models, these features are present in naturally-occurring InvUC in pet dogs. Naturally occurring canine InvUC closely mimics muscle-invasive bladder cancer in humans in regards to cellular and molecular features, molecular subtypes, biological behavior (sites and frequency of metastasis), and response to therapy. Clinical treatment trials in pet dogs with InvUC are considered a win-win scenario; the individual dog benefits from effective treatment, the results are expected to help other dogs, and the findings are expected to translate to better treatment outcomes in humans. This review will provide an overview of canine InvUC, the similarities to the human condition, and the potential for dogs with InvUC to serve as a model to predict the outcomes of targeted therapy and immunotherapy in humans.

Genitourinary tumours in the targeted therapies era: new advances in clinical practice and future perspectives

Genitourinary cancers represent a heterogeneous group of malignancies arising from genitourinary tract, and are responsible for almost 359 000 newly diagnosed cases and 58 420 related deaths in USA. Continuous advances in cancer genetics and genomics have contributed towards changing the management paradigms of these neoplasms. Neoangiogenesis, through the activation of the tyrosine-kinase receptors signalling pathways, represents the key mediator event in promoting tumour proliferation, differentiation, invasiveness and motility. In the last decade, several treatments have been developed with the specific aim of targeting different cell pathways that have been recognized to drive tumour progression. The following review attempts to provide a comprehensive overview of the literature, focusing on new advances in targeted therapies for genitourinary tumours. Furthermore, the promising results of the latest clinical trials and future perspectives will be discussed.

Emerging drugs for urothelial (bladder) cancer

INTRODUCTION

Metastatic urothelial carcinoma has been associated with poor prognosis and a median survival of approximately 12-14 months with standard therapy. Treatment options for decades have been limited to platinum based chemotherapy as first line with few therapeutic options available to the majority who will ultimately progress beyond platinum. Areas covered: This review focuses on the various targeted, antiangiogenic, chemotherapeutic and immunotherapeutic agents currently being developed for the treatment of urothelial carcinoma. Expert opinion: Incorporation of systemic immunotherapy into the treatment of urothelial carcinoma has already fundamentally changed the treatment of this disease. The landscape is rapidly changing and it is likely that immunotherapy will be incorporated into therapy in earlier disease states and in novel combinations. Outcomes in urothelial carcinoma have improved and likely to improve further with ongoing and future clinical research that is discussed in this review.

Systemic therapy in bladder cancer

Systemic chemotherapy is essential for the management of muscle-invasive bladder cancer (MIBC) and metastatic bladder cancer (BCa). Neoadjuvant chemotherapy is key to the management of MIBC with many cisplatin-based regimens. Adjuvant chemotherapy may be considered for selected patients who did not receive neoadjuvant therapy. Systemic chemotherapy with radiotherapy is a critical component of a trimodal bladder-preserving approach and is superior to radiotherapy alone. Cisplatin-based chemotherapy has been the mainstay for metastatic BCa. Immunotherapy in the form of checkpoint inhibitors is a promising new drug for the treatment of BCa. Molecular characterization of each individual BCa is likely to lead to a target-directed therapeutic revolution.

Urinary Bladder Cancer: Biomarkers and Target Therapy, New Era for More Attention

Currently, bladder cancer (BCa) evaluation depends mainly on traditional clinicopathological parameters encompassing tumor stage and grade, which will not reflect the behavior of the disease. Diverse molecular alterations are responsible for the heterogeneous course. The differences in molecular pathogenesis between non-invasive BCa and invasive BCa have been recognized. Molecular biomarkers are promising to predict progression and survival. The management of advanced BCa remains somewhat primitive in comparison with other more common malignancies. This topic will discuss the molecular pathways, biomarkers and potential targets that may improve the outcome in BCa.

Targeting fibroblast growth factor receptors and immune checkpoint inhibitors for the treatment of advanced bladder cancer: New direction and New Hope

Bladder cancer is one of the leading causes of death in Europe and the United States. About 25% of patients with bladder cancer have advanced disease (muscle-invasive or metastatic disease) at presentation and are candidates for systemic chemotherapy. In the setting of metastatic disease, use of cisplatin-based regimens improves survival. However, despite initial high response rates, the responses are typically not durable leading to recurrence and death in the vast majority of these patients with median overall survival of 15months and a 5-year survival rate of ⩽10%. Furthermore, unfit patients for cisplatin have no standard of care for first line therapy in advance disease Most second-line chemotherapeutic agents tested have been disappointing. Newer targeted drugs and immunotherapies are being studied in the metastatic setting, their usefulness in the neoadjuvant and adjuvant settings is also an intriguing area of ongoing research. Thus, new treatment strategies are clearly needed. The comprehensive evaluation of multiple molecular pathways characterized by The Cancer Genome Atlas project has shed light on potential therapeutic targets for bladder urothelial carcinomas. We have focused especially on emerging therapies in locally advanced and metastatic urothelial carcinoma with an emphasis on immune checkpoints inhibitors and FGFR targeted therapies, which have shown great promise in early clinical studies.

Metformin and gefitinib cooperate to inhibit bladder cancer growth via both AMPK and EGFR pathways joining at Akt and Erk

EGFR is a potential therapeutic target for treating bladder cancer, but has not been approved for clinical use yet. Metformin is a widely used antidiabetic drug and has demonstrated interesting anticancer effects on various cancer models, alone or in combination with chemotherapeutic drugs. The efficacy of gefitinib, a well-known EGFR tyrosine kinase inhibitor, combined with metformin was assessed on bladder cancer and underlying mechanisms were explored. This drug combination induced a strong anti-proliferative and anti-colony forming effect and apoptosis in bladder cancer cell lines. Gefitinib suppressed EGFR signaling and inhibited phosphorylation of ERK and Akt. Metformin amplified this inhibitory effect and enhanced gefitinib-induced activation of AMPK signaling pathway. In vivo intravesical treatment of metformin and gefitinib on syngeneic orthotopic mice confirmed the significant inhibitory effect on bladder tumor growth. These two drugs may be an excellent combination for the treatment of bladder cancer through intravesical instillation.

Targeted Therapy for Metastatic Urothelial Cancer: A Work in Progress

The Oncology Grand Rounds series is designed to place original reports published in the Journal into clinical context. A case presentation is followed by a description of diagnostic and management challenges, a review of the relevant literature, and a summary of the authors' suggested management approaches. The goal of this series is to help readers better understand how to apply the results of key studies, including those published in Journal of Clinical Oncology, to patients seen in their own clinical practice.A 64-year-old man presented to the clinic to discuss treatment options for progressive metastatic urothelial carcinoma (UC). At age 57 years, he underwent cystoprostatectomy for bacillus Calmette-Guérin-refractory, high-grade noninvasive UC. He was well until age 61 years, when he developed a left upper-tract UC. He underwent left nephroureterectomy, revealing locally advanced high-grade UC invading the renal parenchyma (pT3). Postoperatively, his renal function precluded adjuvant cisplatin-based chemotherapy. He enrolled onto a clinical trial of autologous cellular immunotherapy targeting human epidermal growth factor receptor 2, for which he was eligible on the basis of human epidermal growth factor receptor 2 positivity (≥ 1+ by immunohistochemistry) in his nephrectomy tumor specimen. He was randomly assigned to observation. Two years later, he developed a left pelvic mass. Biopsy confirmed metastatic high-grade UC. He was briefly treated with gemcitabine and carboplatin, but this was discontinued as a result of rapid symptomatic and radiographic progression at 8 weeks. He underwent palliative radiation to the left pelvic mass to relieve symptoms of pain and leg edema and subsequently elected to enroll onto a clinical trial of a programmed death 1 inhibitor. Concurrently, his previously obtained pelvic mass biopsy sample was sent for panel-based genomic profiling. He now returns for his first restaging evaluation. Imaging shows marked progression on study with new metastases to the liver as well as progressive edema and pain in the left leg, limiting ambulation. Review of his now-available genomic testing results reveals alterations in HRAS (G12D) and ATR (S296, Q257). He elected to enroll onto a single-arm, open-label trial of a farnesyl transferase inhibitor for patients with HRAS mutations.

Targeting molecular aberrations in urothelial carcinoma: are we almost there?

Advances in tumor biology and cancer genetics have led to the development of effective targeted therapies in oncology over the past decade. However, targeted drug development for urothelial carcinoma has been slower than for some other malignancies. The path forward in drug development is through a better understanding of the aberrant pathways driving urothelial tumor development. Steady progress has been made in the characterization of genomic alterations in urothelial carcinoma. The Cancer Genome Atlas (TCGA) project is well underway in the analysis of a large set of urothelial cancer specimens using multiple approaches and technologies. In addition, there are already many well-established mutations and genetic alterations in urothelial carcinoma that likely contribute in an important way to tumor development. In addition, urothelial cancer genome-wide association studies have identified common variants associated with urothelial cancer risk and protein expression that can potentially be therapeutically targeted. Furthermore, the MET pathway has emerged as an exciting target in multiple tumors, including urothelial carcinoma. Our knowledge of how to clinically target many emerging molecular aberrations in urothelial cancer is still in the early stages of development. However, there is much promise in the ongoing research being conducted in urothelial cancer molecular pathogenesis.

Afatinib Activity in Platinum-Refractory Metastatic Urothelial Carcinoma in Patients With ERBB Alterations

PURPOSE

Somatic mutations and copy number variation in the ERBB family are frequent in urothelial carcinoma (UC) and may represent viable therapeutic targets. We studied whether afatinib (an oral, irreversible inhibitor of the ErbB family) has activity in UC and if specific ERBB molecular alterations are associated with clinical response.

PATIENTS AND METHODS

In this phase II trial, patients with metastatic platinum-refractory UC received afatinib 40 mg/day continuously until progression or intolerance. The primary end point was 3-month progression-free survival (PFS3). Prespecified tumor analysis for alterations in EGFR, HER2, ERBB3, and ERBB4 was conducted.

RESULTS

The first-stage enrollment goal of 23 patients was met. Patient demographic data included: 78% male, median age 67 years (range, 36 to 82 years), hemoglobin < 10 g/dL in 17%, liver metastases in 30%, median time from prior chemotherapy of 3.6 months, and Eastern Cooperative Oncology Group performance status ≤ 1 in 100%. No unexpected toxicities were observed; two patients required dose reduction for grade 3 fatigue and rash. Overall, five of 23 patients (21.7%) met PFS3 (two partial response, three stable disease). Notably, among the 21 tumors analyzed, five of six patients (83.3%) with HER2 and/or ERBB3 alterations achieved PFS3 (PFS = 10.3, 7.0, 6.9, 6.3, and 5.0 months, respectively) versus none of 15 patients without alterations (P < .001). Three of four patients with HER2 amplification and three of three patients with ERBB3 somatic mutations (G284R, V104M, and R103G) met PFS3. One patient with both HER2 amplification and ERBB3 mutation never progressed on therapy, but treatment was discontinued after 10.3 months as a result of depressed ejection fraction. The median time to progression/discontinuation was 6.6 months in patients with HER2/ERBB3 alterations versus 1.4 months in patients without alterations (P < .001).

CONCLUSION

Afatinib demonstrated significant activity in patients with platinum-refractory UC with HER2 or ERBB3 alterations. The potential contribution of ERBB3 to afatinib sensitivity is novel. Afatinib deserves further investigation in molecularly selected UC.

Phase II Study of Pazopanib and Paclitaxel in Patients With Refractory Urothelial Cancer

INTRODUCTION

Currently, no standard treatments are available for relapsed or refractory urothelial carcinoma (UC). Paclitaxel has demonstrated efficacy in the treatment of UC when used alone or combined with other cytotoxic therapies. We designed a phase II trial combining paclitaxel with pazopanib, a commonly used antiangiogenic agent with significant antitumor activity in various solid tumors.

PATIENTS AND METHODS

We enrolled 32 patients with refractory UC who had demonstrated disease progression after 2 previous chemotherapeutic regimens. The patients received paclitaxel 80 mg/m² on days 1, 8, and 15 of a 28-day cycle and oral pazopanib 800 mg daily. The primary endpoint was the overall response rate (ORR). The secondary endpoints included progression-free survival, overall survival, and a safety assessment of the combination.

RESULTS

Of the 28 evaluable patients, a complete response was observed in 3 patients and a partial response in 12, with an ORR of 54% (95% confidence interval, 33.9-72.5). The median progression-free and overall survival was 6.2 and 10 months, respectively. The most frequent side effects noted (all grades) were fatigue (63%), diarrhea (44%), and nausea and vomiting (41%). Hematologic toxicities were common and included (all grades) anemia (69%), neutropenia (38%), and thrombocytopenia (47%). Growth factor support was required for 44% of the patients.

CONCLUSION

The combination of paclitaxel and pazopanib resulted in a promising ORR of 54% in patients with advanced pretreated UC. This represents a greater response rate and median survival than found with other existing second-line regimens for UC and is worthy of further study.

Systemic therapy for metastatic bladder cancer in 2016 and beyond

Metastatic urothelial cancer is generally associated with poor outcomes. In the first-line setting, platinum-based chemotherapy is the standard of care but resistance rapidly develops and the vast majority of patients ultimately experience disease progression. Despite several decades of clinical drug development focused on the treatment of platinum-resistant metastatic urothelial cancer, as of late 2015 there are no standard therapies approved by the US FDA in this setting. However, preliminary results from a series of recent trials exploring innovative approaches forecast a 'sea change' in the management of this difficult to treat malignancy. Herein, we review new approaches for the management of patients with metastatic urothelial cancer focused on three key therapeutic target areas: recurrent somatic alterations, the tumor neovasculature and tumor-associated immune escape.

Ten Years of Complete Remission of Pulmonary Metastasis after Post-Cystectomy Palliative Cisplatin-Gemcitabine Chemotherapy with Gefitinib for Muscle Invasive Bladder Cancer: A Case Report

Muscle-invasive bladder cancer (MIBC) is considered one of the most lethal malignancies with high metastatic potential. Usually, metastatic bladder cancer carries worse prognosis with a median survival rate of approximately 6 months, which can be prolonged for up to 14 months with palliative systemic chemotherapy. We present the case of a 61-year-old male patient diagnosed with localized MIBC 10 years ago. He underwent nerve-sparing radical cystectomy with ileal neobladder, but developed pulmonary metastatic disease 7 months postoperatively. Six cycles of gemcitabine/cisplatin combination chemotherapy with an addition of gefitinib as daily oral medication were administered within a randomized phase II clinical trial; this resulted in complete remission of the pulmonary metastases. Until now, the patient is still on gefitinib daily without any side effects. Although, the addition of gefitinib to standard systemic chemotherapy has not been shown to improve the survival in metastatic urothelial cancer, this case represents a very pleasant albeit uncommon long-term outcome.

Steroid Hormone Receptor Signals as Prognosticators for Urothelial Tumor

There is a substantial amount of preclinical or clinical evidence suggesting that steroid hormone receptor-mediated signals play a critical role in urothelial tumorigenesis and tumor progression. These receptors include androgen receptor, estrogen receptors, glucocorticoid receptor, progesterone receptor, vitamin D receptor, retinoid receptors, peroxisome proliferator-activated receptors, and others including orphan receptors. In particular, studies using urothelial cancer tissue specimens have demonstrated that elevated or reduced expression of these receptors as well as alterations of their upstream or downstream pathways correlates with patient outcomes. This review summarizes and discusses available data suggesting that steroid hormone receptors and related signals serve as biomarkers for urothelial carcinoma and are able to predict tumor recurrence or progression.

Muscle-invasive urothelial bladder cancer: an update on systemic therapy

Urothelial carcinoma is a common malignancy that carries a poor prognosis when the disease includes muscle invasion. Metastatic urothelial carcinoma is almost uniformly fatal. The evidence behind treatment options in the neoadjuvant, adjuvant and metastatic settings are discussed in this manuscript, with a focused review of standard and investigational cytotoxic, targeted, and immunotherapy approaches. We have focused especially on neoadjuvant cisplatin-based therapy (supported by level one evidence) and on novel immunotherapy agents such as checkpoint inhibitors, which have shown great promise in early clinical studies.

Elevating the Horizon: Emerging Molecular and Genomic Targets in the Treatment of Advanced Urothelial Carcinoma

Despite recent advances in the identification of genomic alterations that lead to urothelial oncogenesis in vitro, patients with advanced urothelial carcinomas continue to have poor clinical outcomes. In the present review, we focus on targeted therapies that have yielded the most promising results alone or combined with traditional chemotherapy, including the antiangiogenesis agent bevacizumab, the human epidermal growth factor receptor 2 antibody trastuzumab, and the tyrosine kinase inhibitor cabozantinib. We also describe ongoing and developing clinical trials that use innovative approaches, including dose-dense scheduling of singular chemotherapy combinations, prospective screening of tumor tissues for mutational targets and biomarkers to predict chemosensitivity before the determination of the therapeutic regimen, and novel agents that target proteins in the immune checkpoint regulation pathway (programmed cell death protein 1 [PD-1] and anti-PD-ligand 1) that have shown significant potential in preclinical models and early clinical trials. New agents and targeted therapies, alone or combined with traditional chemotherapy, will only be validated through accrual to developing clinical trials that aim to translate these therapies into individualized treatments and improved survival rates in urothelial carcinoma.

A Phase II Study of the Central European Society of Anticancer-Drug Research (CESAR) Group: Results of an Open-Label Study of Gemcitabine plus Cisplatin with or without Concomitant or Sequential Gefitinib in Patients with Advanced or Metastatic Transitional Cell Carcinoma of the Urothelium

INTRODUCTION

This phase II trial evaluated the efficacy and safety of the epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor, gefitinib, in combination with first-line chemotherapy in advanced urothelial cancer.

METHODS

Chemotherapy-naïve patients with advanced or metastatic urothelial carcinoma were randomized 1:1:1 to receive six cycles of chemotherapy (gemcitabine 1,250 mg/m2 on days 1 and 8, and cisplatin 70 mg/m2 on day 1 of every cycle) concomitantly with gefitinib 250 mg/day (arm A); or with sequential gefitinib (arm B); or alone (arm C). The primary endpoint was the time to progression (TTP).

RESULTS

A total of 105 patients received study treatment. Median TTP for arms A, B, and C were 6.1, 6.3, and 7.8 months, respectively. There were no significant differences between treatment arms for any outcomes measured. The most common adverse events were nausea and vomiting.

CONCLUSION

Gefitinib in combination with chemotherapy did not improve efficacy in advanced urothelial cancer.

Targeting Hsp90 in urothelial carcinoma

Urothelial carcinoma, or transitional cell carcinoma, is the most common urologic malignancy that carries significant morbidity, mortality, recurrence risk and associated health care costs. Despite use of current chemotherapies and immunotherapies, long-term remission in patients with muscle-invasive or metastatic disease remains low, and disease recurrence is common. The molecular chaperone Heat Shock Protein-90 (Hsp90) may offer an ideal treatment target, as it is a critical signaling hub in urothelial carcinoma pathogenesis and potentiates chemoradiation. Preclinical testing with Hsp90 inhibitors has demonstrated reduced proliferation, enhanced apoptosis and synergism with chemotherapies and radiation. Despite promising preclinical data, clinical trials utilizing Hsp90 inhibitors for other malignancies had modest efficacy. Therefore, we propose that Hsp90 inhibition would best serve as an adjuvant treatment in advanced muscle-invasive or metastatic bladder cancers to potentiate other therapies. An overview of bladder cancer biology, current treatments, molecular targeted therapies, and the role for Hsp90 inhibitors in the treatment of urothelial carcinoma is the focus of this review.

Novel molecular targets for urothelial carcinoma

INTRODUCTION

Urothelial cancer (UC) remains a significant public health problem, with no new second-line agents FDA-approved in the US. Next-generation sequencing technologies are starting to generate a molecular landscape of UC thus revealing novel molecular targets.

AREAS COVERED

In this review, the authors provide a detailed review of novel molecular targets in UC based on published genomic analyses of urothelial tumors. We provide an overview of each molecular target with a brief discussion of therapeutic strategies and clinical trials targeting each pathway.

EXPERT OPINION

UC continues to be a lethal disease with no FDA-approved effective second-line therapies. Platinum resistance continues to be a daunting clinical problem. Next-generation sequencing methods have led to the elucidation of numerous molecular targets in UC, including PI3K, to the elucidation of numerous molecular targets in UC, including PI3K, ERBB2 and FGFR3, among many others. These molecular perturbations can be exploited therapeutically with targeted therapies in patient populations enriched for these molecular alterations, thus paving the way for precision medicine in UC management.

Molecular biology and targeted therapies for urothelial carcinoma

Metastatic urothelial cancer (UC) is associated with poor prognosis. In the first-line setting, platinum-based chemotherapy is the standard of care but resistance rapidly occurs. With no validated treatment proven to increase survival after platinum failure, there is an urgent unmet medical need to develop new and efficacious cytotoxic agents. A better understanding of the molecular signaling pathways regulating UC has led to the development of new and innovative therapeutic strategies. Despite this, many recent drugs show only modest activity as single agents, and combining them with standard chemotherapy does not seem to enhance efficacy. Ongoing research is producing, however, a generation of new drugs that are showing promising results in clinical trials. This paper aims to review the most important mechanisms in bladder cancer tumorigenesis and describe the new therapeutic options currently undergoing evaluation in clinical trials.

Targeted therapy in advanced bladder cancer: what have we learned?

Despite advances in the treatment of other genitourinary malignancies, no novel therapies have been approved by the US Food and Drug Administration for urothelial carcinoma (UC) in the last 20 years. To date, no clinical trials of targeted agents in UC have led to improvements in survival compared with cytotoxic therapy. This article outlines representative trials of targeted therapies in UC and discusses the significance of genetic preselection in trial design as a method to optimize responses to these agents, thus, hopefully expanding the armamentarium of treatment options against this lethal disease.

Optimal treatment for metastatic bladder cancer

Metastatic bladder cancer is a lethal disease. Cisplatin-based chemotherapy, including the combination regimens gemcitabine-cisplatin and methotrexate-vinblastine-doxorubicin-cisplatin, are the standard first-line therapies. Second-line therapies have modest activity and no significant improvement in patient outcomes. Agents targeting growth, survival, and proliferation pathways have been added to cytotoxic therapy with limited added benefit to date. Modulating host immune response to cancer-associated antigens appears promising, with multiple new therapeutic approaches being pursued. Next-generation sequencing of invasive urothelial carcinoma has provided insights into the biology of this disease and potential actionable targets. Alterations in the receptor tyrosine kinase/Ras pathway and the phosphatidylinositol 3-kinase/protein kinase B/mammalian target of rapamycin pathway represent potential therapeutic targets in advanced disease, and novel agents are in development. Recent data from the Cancer Genome Atlas Research Network bladder cancer cohort and other efforts suggest that mutations in chromatin-regulatory genes are very common in invasive bladder tumors, and are more frequent than in other studied tumors. The discovery of new genomic alterations challenges drug development to change the course of this disease.

Second-line therapies in metastatic urothelial carcinoma

Patients with relapsed or refractory urothelial carcinoma (UC) face a poor prognosis and a dearth of available treatment options that improve their survival. End-organ function and performance status play a vital role in the choice of second-line therapies. Evidence supporting the use of cytotoxic chemotherapy, as single agents or in combination, arises from small phase 2 studies with modest responses. With the evolution of genomic testing in UC, several pathways amenable to available targeted therapies have emerged. Encouraging patient participation in clinical trials is critical to improve patient outcomes and to advance the current modest treatment armamentarium.

Future directions and targeted therapies in bladder cancer

There are substantial unmet needs for patients with metastatic urothelial carcinoma (UC). First-line cisplatin-based chemotherapy regimens yield a median survival of 12 to 15 months and long-term survival in 5% to 15%. Salvage systemic therapy yields a median survival of 6 to 8 months. Hence, the discovery of novel therapeutic targets is of paramount importance. Recent molecular analyses have provided insights regarding molecular tumor tissue alterations on multiple platforms. A multidisciplinary effort using innovative clinical trial designs and exploiting preclinical signals of robust activity guided by predictive biomarkers may provide much needed clinical advances in therapy for advanced UC.