A phase II trial of sorafenib in first-line metastatic urothelial cancer: a study of the PMH Phase II Consortium

Advances in tumor microenvironment and underlying molecular mechanisms of bladder cancer: a systematic review

Bladder cancer is one of the most frequent malignant tumors of the urinary system. The prevalence of bladder cancer among men and women is roughly 5:2, and both its incidence and death have been rising steadily over the past few years. At the moment, metastasis and recurrence of advanced bladder cancer-which are believed to be connected to the malfunction of multigene and multilevel cell signaling network-remain the leading causes of bladder cancer-related death. The therapeutic treatment of bladder cancer will be greatly aided by the elucidation of these mechanisms. New concepts for the treatment of bladder cancer have been made possible by the advancement of research technologies and a number of new treatment options, including immunotherapy and targeted therapy. In this paper, we will extensively review the development of the tumor microenvironment and the possible molecular mechanisms of bladder cancer.

The Potential of Congo Red Supplied Aggregates of Multitargeted Tyrosine Kinase Inhibitor (Sorafenib, BAY-43-9006) in Enhancing Therapeutic Impact on Bladder Cancer

Bladder cancer is a common malignancy associated with high recurrence rates and potential progression to invasive forms. Sorafenib, a multi-targeted tyrosine kinase inhibitor, has shown promise in anti-cancer therapy, but its cytotoxicity to normal cells and aggregation in solution limits its clinical application. To address these challenges, we investigated the formation of supramolecular aggregates of sorafenib with Congo red (CR), a bis-azo dye known for its supramolecular interaction. We analyzed different mole ratios of CR-sorafenib aggregates and evaluated their effects on bladder cancer cells of varying levels of malignancy. In addition, we also evaluated the effect of the test compounds on normal uroepithelial cells. Our results demonstrated that sorafenib inhibits the proliferation of bladder cancer cells and induces apoptosis in a dose-dependent manner. However, high concentrations of sorafenib also showed cytotoxicity to normal uroepithelial cells. In contrast, the CR-BAY aggregates exhibited reduced cytotoxicity to normal cells while maintaining anti-cancer activity. The aggregates inhibited cancer cell migration and invasion, suggesting their potential for metastasis prevention. Dynamic light scattering and UV-VIS measurements confirmed the formation of stable co-aggregates with distinctive spectral properties. These CR-sorafenib aggregates may provide a promising approach to targeted therapy with reduced cytotoxicity and improved stability for drug delivery in bladder cancer treatment. This work shows that the drug-excipient aggregates proposed and described so far, as Congo red-sorafenib, can be a real step forward in anti-cancer therapies.

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.

Current Therapy for Metastatic Urothelial Carcinoma

Urothelial carcinoma (UC) is a highly lethal malignancy in the metastatic state. Platinum-based chemotherapy regimens have been the backbone treatment for patients with advanced UC in the first-line setting. However, a large subset of patients are suboptimal candidates for these combinations owing to poor renal function and/or other comorbidities. Patients who are unable to tolerate or who progress after frontline platinum chemotherapy face a poor outcome. Recent insights into UC biology and immunology are being translated into new therapies for metastatic UC (mUC) including immune checkpoint inhibitors (ICIs), erdafitinib, a FGFR inhibitor, and antibody drug conjugates (ADC) such enfortumab vedotin.

Future Strategies Involving Immune Checkpoint Inhibitors in Advanced Urothelial Carcinoma

OPINION STATEMENT

Immune checkpoint inhibitors have importantly improved the outcome of patients with urothelial carcinoma. Different immune checkpoint inhibitors are currently approved and used in first- and second-line setting. The multiple agents currently approved in these setting make the choice sometimes difficult for clinicians. Furthermore, only a minority of patients present drastic response and long-term benefit with current immunotherapy. In this review, we describe the current use of immunotherapy in urothelial carcinoma but we also highlight the new strategies of treatment involving immune checkpoint inhibitors; we describe the place of immunotherapy with chemotherapy, targeted agents, and anti-angiogenic agents, incorporating the recent results presented at ASCO 2020. This review explores also the different action mechanisms of immune checkpoint inhibitors and the molecular rational to evaluate these agents in other strategies, such as maintenance and salvage strategies. The new advances in biomarker development are also presented.

Treatment of muscle-invasive and advanced bladder cancer in 2020

Bladder cancer accounts for nearly 170,000 deaths worldwide annually. For over 4 decades, the systemic management of muscle-invasive and advanced bladder cancer has primarily consisted of platinum-based chemotherapy. Over the past 10 years, innovations in sequencing technologies have led to rapid genomic characterization of bladder cancer, deepening our understanding of bladder cancer pathogenesis and exposing potential therapeutic vulnerabilities. On the basis of its high mutational burden, immune checkpoint inhibitors were investigated in advanced bladder cancer, revealing durable responses in a subset of patients. These agents are now approved for several indications and highlight the changing treatment landscape of advanced bladder cancer. In addition, commonly expressed molecular targets were leveraged to develop targeted therapies, such as fibroblast growth factor receptor inhibitors and antibody-drug conjugates. The molecular characterization of bladder cancer and the development of novel therapies also have stimulated investigations into optimizing treatment approaches for muscle-invasive bladder cancer. Herein, the authors review the history of muscle-invasive and advanced bladder cancer management, highlight the important molecular characteristics of bladder cancer, describe the major advances in treatment, and offer future directions for therapeutic development.

Emerging biomarkers in urothelial carcinoma: Challenges and opportunities

Advanced urothelial carcinoma (UC) is a very important cause of cancer-related morbidity and mortality with, until recently, only a few available therapeutic options. The treatment landscape has dramatically changed in recent years with the introduction of immune checkpoint inhibitors and the development of novel targeted agents, such as erdafitinib, and antibody-drug conjugates, such as enfortumab vedotin. Cost-effective utilization of this rapidly expanding therapeutic armamentarium can be further optimized via the identification and validation of reliable prognostic and predictive biomarkers that inform prognostication and patient selection. In this review, we aim to summarize examples of recent developments in the rapidly expanding field of emerging biomarkers in UC, outlining challenges and opportunities.

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.

Multicenter Phase 2 Trial of Gemcitabine, Carboplatin, and Sorafenib in Patients With Metastatic or Unresectable Transitional-Cell Carcinoma

BACKGROUND

Sorafenib, an oral tyrosine kinase inhibitor, may enhance the antitumor activity of platinum-based chemotherapy in transitional-cell carcinoma. This study investigated the safety and clinical outcome of adding sorafenib to gemcitabine and carboplatin for patients with advanced transitional-cell carcinoma.

PATIENTS AND METHODS

Subjects with metastatic or unresectable chemotherapy-naive TCC with Eastern Cooperative Oncology Group performance status 0 or 1 received gemcitabine (1000 mg/m² on days 1 and 8) and carboplatin (area under the curve of 5 on day 1) with sorafenib (400 mg 2 times a day on days 2-19 every 21 days) for 6 cycles. Subjects with stable disease or partial or complete response continued to receive sorafenib until disease progression. The primary end point was progression-free survival (PFS) at 5 months with a secondary end point of response (partial or complete).

RESULTS

Seventeen subjects were enrolled. The median number of cycles of gemcitabine and carboplatin with sorafenib provided was 4.4. A total of 15, 5, and 8 subjects required reductions of gemcitabine, carboplatin, and sorafenib, respectively. Thirteen subjects (76%) required multiple dose reductions. Eleven subjects (65%) were free of progression at 5 months. The overall response rate was 54% (95% confidence interval [CI], 0.28-077), with 4 patients experiencing complete response (24%; 95% CI, 0.07-0.50) and 5 partial response (29%; 95% CI, 0.10-0.56); 7 subjects (41%) had stable disease. Median PFS was 9.5 months (95% CI, 0.43-1.26), and median overall survival was 25.2 months (95% CI, 0.96-5.65). One-year PFS was 31%, and 1-year overall survival was 72%. Eleven subjects (65%) discontinued treatment because of toxicity. There were no toxic deaths.

CONCLUSION

Gemcitabine and carboplatin with sorafenib showed clinical activity in advanced TCC, with some prolonged progression-free intervals. However, gemcitabine and carboplatin with sorafenib was associated with significant toxicity, causing discontinuation of therapy in most patients.

A critical review on ramucirumab in the treatment of advanced urothelial cancer

Advanced urothelial cancer (UC) is a lethal disease despite current advances in systemic therapy, including platinum chemotherapy combinations and immune checkpoint inhibition. Tumor angiogenesis is involved in UC growth and metastatic progression. Proangiogenic signaling through the VEGFR is a key process in UC with prognostic significance. Targeting of VEGFR2 with the monoclonal antibody ramucirumab has been tested in various different tumor types. In this review, we discuss the development of the drug in the context of its preclinical and clinical use with a focus on UC. Improvements in our ability to predict responses and resistance are key for maximizing its efficacy and selecting the most appropriate combinations with other active agents.

Emerging first line treatment options for bladder cancer: a review of phase II and III therapies in the pipeline

INTRODUCTION

The treatment of urothelial carcinoma (UC) had remained unchanged for several years until the recent FDA approval of immune checkpoint inhibitors (CPIs) in the salvage setting. Novel dual CPI-CPI and CPI-chemotherapy combinations are now being investigated aggressively as first line therapy for metastatic disease. Areas covered: We discuss the recent insights into the tumor biology of UC, which may impact the prognosis as well as assist in developing precision medicine. This is followed by an overview of existing treatment including conventional chemotherapy as well as the trials that led to the recent approval of PD-1 and PD-L1 inhibitors. Ongoing phase II and phase III trials developing PD-1/PD-L1 inhibitors, CTLA-4 inhibitors and VEGF inhibitors as first-line therapy are discussed. Expert opinion: The treatment paradigm for the first-line therapy of UC is expected to shift from conventional platinum-based combination chemotherapy towards novel therapy incorporating CPI immunotherapy. Finding the right combination of drugs in the appropriate disease setting and identifying the right patient population based on biomarkers are important questions to be answered. Another major challenge will be the financial burden associated with these new drugs.

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.

Interleukin-27 augments the inhibitory effects of sorafenib on bladder cancer cells

Both sorafenib and interleukin-27 (IL-27) are antineoplastic drugs. This study aimed to investigate the synergistic effect of these two drugs on bladder cancer cells. HTB-9 and T24 cells were stimulated with IL-27 (50 ng/mL), sorafenib (2 μM) or the synergistic action of these two drugs. The cells without treatment acted as control. Cell proliferation, apoptosis and invasion were measured by bromodeoxyuridine assay, flow cytometry and modified Boyden chamber, respectively. Simultaneously, both modified Boyden chamber and scratch assay were used to assess cell migration. Finally, the phosphorylation levels of key kinases in the Akt/mechanistic target of rapamycin (mTOR)/mitogen-activated protein kinase (MAPK) pathway, and expression levels of matrix metalloproteinase (MMP)-2 and MMP-9 were detected by western blot analysis. Stimulation with IL-27 or sorafenib repressed proliferation, migration and invasion but promoted apoptosis, and the effects were all enhanced by the combination of these two drugs in HTB-9 cells. The effect of the combined treatment on bladder cancer cells was verified in T24 cells. Additionally, the phosphorylation levels of AKT, mTOR and MAPK as well as the expression levels of MMP-2 and MMP-9 were all decreased by a single treatment of IL-27 or sorafenib, and further decreased by the combined treatment of these two drugs. The combination of IL-27 and sorafenib inhibited proliferation, migration and invasion and promoted apoptosis of bladder cancer cells compared with mono-drug treatment. Additionally, the AKT/mTOR/MAPK pathway might be implicated in the functional effects by down-regulations of MMP-2 and MMP-9.

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.

Inefficiencies and Patient Burdens in the Development of the Targeted Cancer Drug Sorafenib: A Systematic Review

Failure in cancer drug development exacts heavy burdens on patients and research systems. To investigate inefficiencies and burdens in targeted drug development in cancer, we conducted a systematic review of all prelicensure trials for the anticancer drug, sorafenib (Bayer/Onyx Pharmaceuticals). We searched Embase and MEDLINE databases on October 14, 2014, for prelicensure clinical trials testing sorafenib against cancers. We measured risk by serious adverse event rates, benefit by objective response rates and survival, and trial success by prespecified primary endpoint attainment with acceptable toxicity. The first two clinically useful applications of sorafenib were discovered in the first 2 efficacy trials, after five drug-related deaths (4.6% of 108 total) and 93 total patient-years of involvement (2.4% of 3,928 total). Thereafter, sorafenib was tested in 26 indications and 67 drug combinations, leading to one additional licensure. Drug developers tested 5 indications in over 5 trials each, comprising 56 drug-related deaths (51.8% of 108 total) and 1,155 patient-years (29.4% of 3,928 total) of burden in unsuccessful attempts to discover utility against these malignancies. Overall, 32 Phase II trials (26% of Phase II activity) were duplicative, lacked appropriate follow-up, or were uninformative because of accrual failure, constituting 1,773 patients (15.6% of 11,355 total) participating in prelicensure sorafenib trials. The clinical utility of sorafenib was established early in development, with low burden on patients and resources. However, these early successes were followed by rapid and exhaustive testing against various malignancies and combination regimens, leading to excess patient burden. Our evaluation of sorafenib development suggests many opportunities for reducing costs and unnecessary patient burden in cancer drug development.

Incorporating VEGF-targeted therapy in advanced urothelial cancer

Patients with relapsed or refractory urothelial carcinoma (UC) have poor prognosis coupled with few options for systemic treatment. The role of angiogenesis in the evolution of cancers has been established, and studies have shown that it plays a key role in the pathogenesis of UC. Many targeted agents have been used in phase I-II trials for the treatment of UC, with encouraging but modest results. Recently, studies combining angiogenesis inhibitors with other chemotherapeutic agents were able to achieve objective responses higher than most commonly used second-line therapies in UC. Future efforts in investigating these therapies in UC rely on identification of biomarkers and other predictors of response to anti-VEGF therapy.

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.

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.

The role of genomics in the management of advanced bladder cancer

OPINION STATEMENT

Advanced bladder cancer (ABC) is an aggressive malignancy with a poor prognosis. For the last 30 years, the standard of care for this disease has consisted of combination chemotherapy with a platinum-containing regimen as first-line therapy. Cisplatin is the most active cytotoxic agent against bladder cancer, but because of competing comorbidities, many patients are ineligible for this agent and instead receive carboplatin. The two-drug regimen of cisplatin and gemcitabine was found to be better tolerated and have comparable efficacy as the four-drug regimen of methotrexate, vinblastine, doxorubicin, and cisplatin (MVAC) in a randomized study of patients with advanced disease. Therefore, cisplatin (or carboplatin) and gemcitabine is the most commonly used first-line regimen in this setting. No agents have been approved by the Food and Drug Administration (FDA) for second-line therapy in ABC. If patients are eligible for additional systemic treatment at the time of progression, options include single-agent therapy such as a taxane or pemetrexed, though given the lack of standard approaches participation in a clinical trial should be strongly encouraged. Recent molecular characterization of ABC reveals significant genetic heterogeneity and actionable genomic alterations in the majority of tumors. Emerging therapies may effectively target known molecular drivers of ABC, including the FGFR2, EGFR/HER2, VEGF, MET, and PI3/AKT/mTOR pathways. Reports of dramatic and prolonged responses to targeted therapy provide additional support for the use of genome sequencing in the rationale selection of treatment for subsets of patients. The current focus of clinical trial development is to design molecularly driven studies that "match" tumors with driver mutations and appropriate targeted therapies rather than a "one-size-fits-all" approach based on clinical and pathologic parameters of disease. The hope of patients and clinicians alike is that this therapeutic approach combined with novel agents may usher in a new era of effective treatments for patients with ABC.

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.

Safety and efficacy of combination therapy with low-dose gemcitabine, paclitaxel, and sorafenib in patients with cisplatin-resistant urothelial cancer

Various regimens including molecular targeted agents have been examined in patients with cisplatin (CDDP)-resistant urothelial cancer (UC). However, some studies have been stopped owing to the development of severe adverse events. The main aim of this study was to examine the anticancer effects, changes in the quality of life (QoL), and safety of combined therapy of low-dose gemcitabine, paclitaxel, and sorafenib (LD-GPS) in patients with CDDP-resistant UC. Twenty patients were treated with gemcitabine (700 mg/m(2) on day 1), paclitaxel (70 mg/m(2) on day 1), and sorafenib (400 mg/day on days 8-22). QoL and pain relief were evaluated using the short-form survey (SF)-36 for bodily pain and the visual analog scale (VAS). VAS scores were significantly decreased by both the second- and third-line therapies (P = 0.012 and 0.028, respectively). The bodily pain score from the SF-36 survey was also significantly (P = 0.012) decreased. Complete responses, partial responses, and stable disease were found in 0 (0.0 %), 1 (5.0 %), and 13 patients (65 %), respectively. The median (interquartile range) period of overall survival after starting of this therapy was 7 (5-11) months. Three patients (15.0 %) stopped therapy because of grade 3 fatigue and hand-foot reactions. LD-GPS therapy was well tolerated by patients with CDDP-resistant UC. QoL was maintained, and improvements in their pain levels were found after treatment; pain relief was detected after third-line therapy. We suggest that this treatment regimen is worthy of consideration as second- and third-line therapy for patients with CDDP-resistant UC.

Emerging concepts on drug resistance in bladder cancer: Implications for future strategies

The combination chemotherapies with methotrexate plus vinblastine, doxorubicin and cisplatin (MVAC or CMV regimens) or gemcitabine plus cisplatin represent the standard as first-line therapy for patients with metastatic urothelial cancer. In Europe, vinflunine is an option for second-line therapy for patients progressed during first-line or perioperative platinum-containing regimen. Alternative regimens containing taxanes and/or gemcitabine may be valuated case by case. Furthermore, carboplatin should be considered in patients unfit for cisplatin both in the first and second-line setting. Based on these findings, a better comprehension of the mechanisms underlying the development of drug resistance in patients with bladder cancer will represent a major step forward in optimizing patients' outcome. This article reviews the current knowledge of the mechanisms and emerging strategies to overcome resistance in patients with 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.

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.

Sorafenib induces cathepsin B-mediated apoptosis of bladder cancer cells by regulating the Akt/PTEN pathway. The Akt inhibitor, perifosine, enhances the sorafenib-induced cytotoxicity against bladder cancer cells

Sorafenib, a tyrosine kinase inhibitor, has been demonstrated to exert anti-tumor effects. However, the molecular mechanisms underlying its effects on bladder cancer remain unknown.

Here, we evaluated the mechanisms responsible for the sorafenib-induced anti-tumor effects on 5637 and T24 bladder cancer cells. We demonstrated that sorafenib reduces cell viability, stimulates lysosome permeabilization and induces apoptosis of bladder cancer cells. These effects are dependent by the activation of cathepsin B released from lysosomes. The sorafenib-increased cathepsin B activity induced the proteolysis of Bid into tBid that stimulates the intrinsic pathway of apoptosis characterized by mitochondrial membrane depolarization, oxygen radical generation and cytochrome c release. Moreover, we found that cathepsin B enzymatic activity, induced by sorafenib, is dependent on its dephosphorylation via PTEN activation and Akt inactivation. Pretreatment with orthovanadate rescued bladder cancer cells from apoptosis. In addition, the Akt inhibitor perifosine increased the sensitivity of bladder cancer cells to sorafenib-induced cytotoxicity.

Overall, our results show that apoptotic cell death induced by sorafenib in bladder cancer cells is dependent on cathepsin B activity and involved PTEN and Akt signaling pathways. The Akt inhibitor perifosine increased the cytotoxic effects of sorafenib in bladder cancer cells.

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.

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.

Multiple mechanisms mediate resistance to sorafenib in urothelial cancer

Genetic and epigenetic changes in the mitogen activated protein kinase (MAPK) signaling render urothelial cancer a potential target for tyrosine kinase inhibitor (TKI) treatment. However, clinical trials of several TKIs failed to prove efficacy. In this context, we investigated changes in MAPK signaling activity, downstream apoptotic regulators and changes in cell cycle distribution in different urothelial cancer cell lines (UCCs) upon treatment with the multikinase inhibitor sorafenib. None of the classical sorafenib targets (vascular endothelial growth factor receptor 1/-receptor 2, VEGFR1/-R2; platelet-derived growth factor receptor α/-receptor β, PDGFR-α/-β; c-KIT) was expressed at significant levels leaving RAF proteins as its likely molecular target. Low sorafenib concentrations paradoxically increased cell viability, whereas higher concentrations induced G1 arrest and eventually apoptosis. MAPK signaling remained partly active after sorafenib treatment, especially in T24 cells with an oncogenic HRAS mutation. AKT phosphorylation was increased, suggesting compensatory activation of the phosphatidylinositol-3-kinase (PI3K) pathway. Sorafenib regularly down regulated the anti-apoptotic myeloid cell leukemia 1 (Mcl-1) protein, but combinatorial treatment with ABT-737 targeting other B-cell lymphoma 2 (Bcl-2) family proteins did not result in synergistic effects. In summary, efficacy of sorafenib in urothelial cancer cell lines appears hampered by limited effects on MAPK signaling, crosstalk with further cancer pathways and an anti-apoptotic state of UCCs. These observations may account for the lack of efficacy of sorafenib in clinical trials and should be considered more broadly in the development of signaling pathway inhibitors for drug therapy in urothelial carcinoma.

Dovitinib: rationale, preclinical and early clinical data in urothelial carcinoma of the bladder

INTRODUCTION

Bladder cancer (BC) is the third and fifth cancer in men in terms of incidence and mortality in the US. Overexpression and mutations of fibroblast growth factor receptor 3 (FGFR3) are frequently found in BC and can represent a very interesting therapeutic target. Different FGFR3-targeted strategies have been investigated through in vitro and in vivo settings, including FGFR3 tyrosine kinase inhibitors such as dovitinib .

AREAS COVERED

The authors review the data that provide a scientific rationale for FGFR3-targeted therapy in BC. They also provide an evaluation of the currently available in vitro and in vivo data on the use of dovitinib in BC patients.

EXPERT OPINION

The development and progression of BC rely on a very complex signaling network that involves many different receptors aside from FGFR3 and VEGFR2. The involved signaling network can also be very different from one BC to the other, and can also evolve through time in the same patient. Inhibiting only one single target may thus not be sufficient to achieve a complete downstream oncogenic signaling blockage. Additionally, in vitro data on the use of neutralizing monoclonal antibodies targeting FGFR3 show that it can be a more efficient strategy to reach the same goal, with the potential advantage of less toxicity.

Cytotoxic and DNA-targeted therapy in urothelial cancer: have we squeezed the lemon enough?

Urothelial cancer has long been known as a chemotherapy-sensitive disease. However, clinical trial data to date suggest a plateau to the magnitude of benefit from cytotoxic therapy alone. In spite of level 1 evidence supporting cisplatin-based chemotherapy for patients with muscle-invasive and metastatic urothelial cancer, underuse prevails among patients with localized disease and only a modest survival benefit exists in the metastatic setting, although trials have consistently demonstrated that there is a subset of patients who clearly benefit. Recent comprehensive genomic profiling has identified a high prevalence of actionable genomic alterations as well as other potential targets yet to be fully understood. Modern clinical trials must now focus on identifying predictive biomarkers to select those patients who will benefit most from cytotoxic chemotherapy, molecularly targeted therapy, or potentially both.

Targeted therapies in urothelial carcinoma

PURPOSE OF REVIEW

Greater understanding of the biology and genetics of urothelial carcinoma is helping to identify and define the role of molecules and pathways appropriate for novel-targeted therapies. Here, we review the targeted therapies that have been reported or are in ongoing urothelial carcinoma clinical trials, and highlight molecular targets characterized in preclinical and clinical studies.

RECENT FINDINGS

Trials in nonmuscle-invasive bladder cancer are evaluating the role of immunotherapy and agents targeting vascular endothelial growth factor (VEGF) or fibroblast growth factor receptor-3. In muscle-invasive bladder cancer, neoadjuvant studies have focused on combining VEGF agents with chemotherapy; adjuvant studies are testing vaccines and agents targeting the human epidermal growth factor receptor 2, p53, and Hsp27. In the first-line treatment of metastatic urothelial carcinoma, tubulin, cytotoxic T-lymphocyte antigen 4, Hsp27, and p53 are novel targets in clinical trials. The majority of targeted agents studied in urothelial carcinoma are in the second-line setting; new targets include CD105, polo-like kinase-1, phosphatidylinositide 3-kinases (PI3K), transforming growth factor β receptor/activin receptor-like kinase β, estrogen receptor, and the hepatocyte growth factor receptor (HGFR or MET).

SUMMARY

Development of targeted therapies for urothelial carcinoma is still in early stages, consequently there have been no major therapeutic advances to date. However, greater understanding of urothelial carcinoma and solid tumor biology has resulted in a proliferation of clinical trials that could lead to significant advances in treatment strategies.

Chemotherapeutic and targeted biological agents for metastatic bladder cancer: a comprehensive review

The American Cancer Society estimates that 73 510 new cases of bladder cancer will be diagnosed and 15 000 deaths will result this year. The paper summarizes the clinical evidence for the use of platinum-based, non-platinum-based and new targeted biological agents, while reporting the future directions in the treatment of metastatic bladder cancer. For cisplatin-base regimens, the combination of methotrexate, vinblastine, doxorubicin and cisplatin (M-VAC) has been the mainstream treatment for both advanced and metastatic bladder cancers. It showed significant improvement in the complete response rate and overall survival time in comparison with single-agent cisplatin. For cisplatin-ineligible patients, namely patients with renal impairment, symptomatic cardiac disease and poor performance status, alternative therapies consisting of paclitaxel, gemcitabine and carboplatin were shown to be of benefit. Pemetrexed and vinflunine have also shown effectiveness, with small but demonstrable overall survival benefits. Gemcitabine-based doublet therapies (combined with paclitaxel, docetaxel, irinotecan, oxaliplatin or epirubicin) have all been shown to be effective and well-tolerated. Several new targeted therapies, such as gefetinib, sorafenib and lapatinib, have received attention in recent years; however, their effectiveness as single agents in a relapse setting have not been optimal and more studies are warranted.

Emerging drugs for urothelial carcinoma

INTRODUCTION

Advanced urothelial carcinoma is associated with a poor prognosis. In the metastatic setting, the response rate to first-line, cisplatin-containing chemotherapy is high, but survival is poor. Second-line treatment options are limited. Advanced age at diagnosis and the presence of comorbidities often preclude treatment with cisplatin-containing regimens.

AREAS COVERED

This review addresses the current therapy of urothelial carcinoma, the unmet needs in treatment and the status of drug development in this disease. The molecular targets identified and efforts to incorporate targeted agents into therapy will be addressed.

EXPERT OPINION

There have been no major advances in the treatment of urothelial carcinoma in three decades. Despite high response rates in the first-line setting, survival is limited. Major impediments to improved outcomes include poor durability of response to first-line chemotherapy and lack of second-line treatments. Better understanding in tumor biology has identified multiple targets in urothelial carcinoma; however, such discoveries have yet to lead to the incorporation of targeted agents into the routine treatment of urothelial carcinoma. Multiple ongoing clinical trials are investigating the use of targeted agents in urothelial carcinoma. Continued efforts are underway to better understand the molecular drivers of disease and such efforts are likely to identify additional therapeutic targets.

Inhibitory role of the small leucine-rich proteoglycan biglycan in bladder cancer

BACKGROUND

Urothelial bladder cancer is the ninth most common cancer. Despite surgical and chemotherapeutic treatment the prognosis is still poor once bladder cancer progresses to a muscle-invasive state. Discovery of new diagnostic markers and pathophysiologic effectors might help to contribute to novel diagnostic and therapeutic options. The extracellular matrix microenvironment shaped by the extracellular matrix critically affects tumor cell and stroma cell functions. Therefore, aim of the present study was to assess the possible implication of the small leucine-rich proteoglycan biglycan in progression of human urothelial bladder cancer.

METHODS AND RESULTS

For this purpose tumor biopsies of 76 bladder cancer patients with different tumor stages (pTa, pT1-T4) were investigated with respect to biglycan expression and correlated with a long-term (10 years) clinical follow-up. Interestingly, higher biglycan mRNA expression was associated with higher tumor stages and muscle invasiveness. In vitro knock-down of endogenous biglycan in human urothelial carcinoma cells (J82 cells) increased proliferation, whereas addition of recombinant biglycan and overexpression of biglycan inhibited tumor cell proliferation. In line with this growth-inhibitory effect of biglycan, transplantation of J82 cells after knock-down of biglycan resulted in significantly increased growth of subcutaneous xenograft tumors in nude mice in vivo. Furthermore, treatment with two anti-proliferative, multi-receptor tyrosine kinase inhibitors-sunitinib and sorafenib-strongly upregulated biglycan expression. Collectively, the experimental data suggest that high biglycan expression is associated with reduced tumor cell proliferation. In accordance, Kaplan-Meier analysis revealed higher 10-year survival in patients with high biglycan mRNA expression in tumor biopsies.

CONCLUSION

In conclusion, the present data suggest that biglycan is an endogenous inhibitor of bladder cancer cell proliferation that is upregulated in response to anti-proliferative tyrosine kinase inhibitors. In addition, high biglycan expression is associated with favorable prognosis.