TROPHY-U-01: A Phase II Open-Label Study of Sacituzumab Govitecan in Patients With Metastatic Urothelial Carcinoma Progressing After Platinum-Based Chemotherapy and Checkpoint Inhibitors

Current status and future prospects of antibody-drug conjugates in urological malignancies

Antibody-drug conjugates represent a promising new treatment option that uses the targeting ability of an antibody to deliver cytotoxic drugs directly to tumors. Antibody-drug conjugates provide the opportunity to deliver drugs to antigen-expressing cancer cells while minimizing toxicity to normal tissue, achieving wider therapeutic windows. To date, three antibody-drug conjugates have been approved by the US Food and Drug Administration, and many antibody-drug conjugates are under clinical development for urological malignancies. In this paper, we review the mechanism, history, and development of antibody-drug conjugates, and review the current landscape of antibody-drug conjugates in urological malignancies including 12 targets and 18 antibody-drug conjugates in prostate cancer, renal cancer, and urothelial cancer. Furthermore, we review the rational combination of antibody-drug conjugates with immune checkpoint inhibitors and consider future prospects to enhance the therapeutic activity of antibody-drug conjugates in urological malignancies.

Antibody-Drug Conjugates in Uro-Oncology

Currently available treatment options for patients with refractory metastatic prostate, bladder, or kidney cancers are limited with the prognosis remaining poor. Advances in the pathobiology of tumors has led to the discovery of cancer antigens that may be used as the target for cancer treatment. Antibody-drug conjugates (ADCs) are a relatively new concept in cancer treatment that broaden therapeutic landscape. ADCs are examples of a 'drug delivery into the tumor' system composed of an antigen-directed antibody linked to a cytotoxic drug that may release cytotoxic components after binding to the antigen located on the surface of tumor cells. The clinical properties of drugs are influenced by every component of ADCs. Regarding uro-oncology, enfortumab vedotin (EV) and sacituzumab govitecan (SG) are currently registered for patients with locally advanced or metastatic urothelial cancer following previous treatment with an immune checkpoint inhibitor (iCPI; programmed death receptor-1 [PD-1] or programmed death-ligand 1 [PD-L1]) inhibitor) and platinum-containing chemotherapy. The EV-301 trial showed that EV significantly prolonged the overall survival compared with classic chemotherapy. The TROPHY-U-01 trial conducted to evaluate SG demonstrated promising results as regards the objective response rate and duration of response. The safety and efficacy of ADCs in monotherapy and polytherapy (mainly with iCPIs) for different cancer stages and tumor types are assessed in numerous ongoing clinical trials. The aim of this review is to present new molecular biomarkers, specific mechanisms of action, and ongoing clinical trials of ADCs in genitourinary cancers. In the expert discussion, we assess the place of ADCs in uro-oncology and discuss their clinical value.

Impact of salvage cytotoxic chemotherapy on prognosis in patients with recurrence after radical cystectomy: a multi-institutional retrospective study

Background

In patients experiencing disease recurrence after radical cystectomy (RC) for bladder cancer, data about the impact of clinicopathologic factors, including salvage treatment using cytotoxic chemotherapy, on the survival are scarce. We investigated the prognostic value of clinicopathologic factors and the treatment effect of salvage cytotoxic chemotherapy (SC) in such patients.

Methods

In this retrospective study, we evaluated the clinical data for 86 patients who experienced recurrence after RC. Administration of SC or of best supportive care (BSC) was determined in consultation with the urologist in charge and in accordance with each patient’s performance status, wishes for treatment, and renal function. Statistical analyses explored for prognostic factors and evaluated the treatment effect of SC compared with BSC in terms of cancer-specific survival (CSS).

Results

Multivariate analyses showed that liver metastasis after RC (hazard ratio [HR] 2.13; 95% confidence interval [CI] 1.17 to 3.85; P = 0.01) and locally advanced disease at RC (HR 1.92; 95% CI 1.06 to 3.46; P = 0.03) are independent risk factors for worse CSS in patients experiencing recurrence after RC. In a risk stratification model, patients were assigned to one of two groups based on liver metastasis and locally advanced stage. In the high-risk group, which included 68 patients with 1–2 risk factors, CSS was significantly better for patients receiving SC than for those receiving BSC (median survival duration: 9.4 months vs. 2.4 months, P = 0.005). The therapeutic effect of SC was not related to a history of adjuvant chemotherapy.

Conclusions

The present study indicated the potential value of 1st-line SC in patients experiencing recurrence after RC even with advanced features, such as liver metastasis after RC and locally advanced disease at RC.

Genomics and Immunomics in the Treatment of Urothelial Carcinoma

Urothelial carcinoma is a complex cancer with genomic immunomic drivers that have prognostic and predictive treatment implications. Identifying potential targetable alterations via next-generation sequencing and RNA sequencing may allow for elucidation of such targets and exploitation with targeted therapeutics. The role of immunotherapy in treating urothelial carcinoma has shown benefit, but it is unclear in which patients immunotherapeutics have the highest yield. Continuing efforts into better identifying which patients may benefit most from targeted therapies, immunotherapies, and combination therapies may ultimately lead to improved outcomes for patients with this disease.

Metastatic Urothelial Carcinoma: Have We Take the Road to the Personalized Medicine?

Urothelial cancer is a lethal malignancy characterized by a wide diffusion in Western countries due to a larger exposure to known risk factors, such as aromatic amines, tobacco smoke and benzene [...].

Head-to-Head Comparison of the Expression Differences of NECTIN-4, TROP-2, and HER2 in Urothelial Carcinoma and Its Histologic Variants

Background

Antibody–drug conjugates (ADC), such as enfortumab vedotin (EV), sacituzumab govitecan (SG), and RC-48, have shown outstanding response rates to local advanced or metastatic urothelial carcinoma (UC). However, their corresponding target expression characteristics in UC and its histologic variants were unknown.

Methods

We detected the expression of NECTIN-4, TROP-2, and HER2, which are the corresponding targets of ADCs EV, SG, and RC-48 in muscle-invasive UC through immunohistochemistry.

Results

161 consecutive samples from 2017 to 2021 of muscle-invasive UC and its histologic variants were obtained in Peking University First Hospital. Variant histology types included 72UC, 10 squamous carcinomas, 23 glandular carcinomas, 19 small cell carcinomas, 19 micropapillary variants, and 18 nested variants. NECTIN-4 expression was found to be 57/72 (79.2%), 10/10 (100%), 15/23 (65.2%), 4/19 (21.1%), 15/19 (78.9%), and 16/18 (88.9%) in conventional UC, squamous carcinoma, glandular carcinoma, small cell carcinoma, micropapillary, and nested variant, respectively, compared with 65/72 (90.3%), 8/10 (80.0%), 13/23 (56.5%), 3/19 (15.8%), 16/19 (84.2%), and 15/18 (83.3%) of TROP-2, and 26/72 (36.1%), 0, 5/23 (21.7%), 6/19 (31.6%), 5/19 (26.3%), and 7/18 (38.9%) of HER2.

New Treatment Options for Patients With Bladder Cancer

Bladder cancer is not rare—in men, it is the fourth most common cancer and the eighth leading cause of cancer-related death. The emergence of new systemic therapies, approval of PD-1 and PD-L1 inhibitors, and progress in the development of biomarkers have revolutionized the treatment of this urologic malignancy. The current NCCN Guidelines, which reflect the most up-to-date, evidence-based data relating to the evaluation and management of bladder cancer, support the incorporation of some of these novel therapeutics into clinical practice.

Antibody-drug conjugates: beyond current approvals and potential future strategies

The recent approvals for antibody-drug conjugates (ADCs) in multiple malignancies in recent years have fuelled the ongoing development of this class of drugs. These novel agents combine the benefits of high specific targeting of oncogenic cell surface antigens with the additional cell kill from high potency cytotoxic payloads, thus achieving wider therapeutic windows. This review will summarise the clinical activity of ADCs in tumour types not covered elsewhere in this issue, such as gastrointestinal (GI) and genitourinary (GU) cancers and glioblastoma (GBM). In addition to the ongoing clinical testing of existing ADCs, there is substantial preclinical and early phase testing of newer ADCs or ADC incorporating strategies. This review will provide selected insights into such future development, focusing on the development of novel ADCs against new antigen targets in the tumour microenvironment (TME) and combination of ADCs with immuno-oncology (IO) agents.

Recent Advances in Medical Therapy for Urological Cancers

The mainstay of medical treatment has been tyrosine kinase inhibitors (TKIs) for renal cell cancer (RCC), cytotoxic chemotherapy for urothelial cancer (UC), and androgen deprivation therapy for prostate cancer. These therapeutic modalities still play important roles in these malignancies. However, immune checkpoint inhibitors (ICIs) that target PD-1/PD-L1 or CTLA-4 are being rapidly introduced for the treatment of metastatic urological cancers, just as they have been for other malignancies. Currently, the paradigm of medical treatment for patients with metastatic urological cancer is dramatically changing. Accordingly, we need to organize and summarize the new therapeutic tools, which include immune checkpoint inhibitors, poly (ADP-ribose) polymerase (PARP) inhibitors, and antibody-drug conjugates (ADCs). This review provides an overview of agents and regimens that have just launched or will be launched in the near future in Japan. Based on the promising anti-tumor efficacy and manageable safety profiles being demonstrated in clinical trials, these new agents and therapies are expected to be rapidly introduced in Japanese clinical practice. Additionally, the newly designed ADC, enfortumab vedotin, which comprises a fully human monoclonal antibody conjugated to an anti-cancerous agent via a protease-cleavable linker, has just been launched in Japan. In order to provide the optimal treatment for our patients, we need to completely understand these new therapeutic tools.

2022 American Society of Clinical Oncology (ASCO) Genitourinary Cancers Symposium: Meeting highlights

The 2022 American Society of Clinical Oncology (ASCO) Genitourinary (GU) Cancers Symposium was held in San Francisco and online from February 17–19, 2022. Following the symposium, on February 22, the Canadian Urological Association (CUA) held an online webinar where Canadian experts highlighted key research findings in prostate, bladder, and kidney cancers. In this report, we summarize these exciting advances in GU oncology. The entire webinar can be viewed on the CUA website, and meeting abstracts can be viewed at the ASCO meeting library.

Molecularly Targeted Therapy towards Genetic Alterations in Advanced Bladder Cancer

Despite the introduction of immune checkpoint inhibitors and antibody-drug conjugates to the management of advanced urothelial carcinoma, the disease is generally incurable. The increasing incorporation of next-generation sequencing of tumor tissue into the characterization of bladder cancer has led to a better understanding of the somatic genetic aberrations potentially involved in its pathogenesis. Genetic alterations have been observed in kinases, such as FGFRs, ErbBs, PI3K/Akt/mTOR, and Ras-MAPK, and genetic alterations in critical cellular processes, such as chromatin remodeling, cell cycle regulation, and DNA damage repair. However, activating mutations or fusions of FGFR2 and FGFR3 remains the only validated therapeutically actionable alteration, with erdafitinib as the only targeted agent currently approved for this group. Bladder cancer is characterized by genomic heterogeneity and a high tumor mutation burden. This review highlights the potential relevance of aberrations and discusses the current status of targeted therapies directed at them.

[Update on systemic treatment of urothelial cancer: therapy in transition]

The systemic treatment of locally advanced and metastatic urothelial carcinoma has been changing at a breathtaking pace for a few years. However, platinum-based chemotherapy continues to be the central component of perioperative therapies and first-line treatment in the metastatic stage. Immunotherapies with immune checkpoint inhibitors are now an integral part of therapy algorithms. New targeted forms of chemotherapy are about to be approved. Advances in understanding the molecular genetic analysis of tumour tissue will soon enable personalised therapy options. This article is intended to provide an overview of current systemic therapy options and the underlying database. New developments are identified by presenting ongoing phase III trials. After reading this article, the reader should feel informed about the current status of systemic therapy for urothelial carcinoma.

Management of Advanced Urothelial Carcinoma in Older and Frail Patients: Have Novel Treatment Approaches Improved Their Care?

Patients with urothelial carcinoma tend to be older and frailer with a large number of chronic medical conditions. This is particularly pronounced in those with unresectable locally advanced and metastatic urothelial carcinoma. Prior to 2016, treatment options in advanced urothelial carcinoma were limited to chemotherapy, and as a result, a large number of patients were not receiving disease-directed management. Over the last 6 years, multiple alternative modalities including immune checkpoint inhibitors and targeted therapies have been introduced. They are being utilized clinically in older and frail patients, but there are limited studies investigating outcomes in these specific populations. Based upon current evidence, age does not impact the efficacy and tolerance of immune checkpoint inhibitors if patients are fit enough to receive therapy. In frailer patients, immune checkpoint inhibitors appear to be safe, but outcomes from largely retrospective studies demonstrate mixed data regarding their efficacy. Although there are indications from clinical trials that enfortumab vedotin, sacituzumab govitecan, and erdafitinib are also efficacious irrespective of age, there is still not enough evidence to draw definitive conclusions about their use in older and frail patients. Regardless, in all older patients with advanced urothelial carcinoma, it is critical to evaluate for frailty through geriatric screening tools and comprehensive assessments. Combining these evaluations with consideration of an individual patient's goals should be the foundation upon which therapeutic decisions are made in this population of patients.

Value of c-MET and Associated Signaling Elements for Predicting Outcomes and Targeted Therapy in Penile Cancer

Whereas the lack of biomarkers in penile cancer (PeCa) impedes the development of efficacious treatment protocols, preliminary evidence suggests that c-MET and associated signaling elements may be dysregulated in this disorder. In the following study, we investigated whether c-MET and associated key molecular elements may have prognostic and therapeutic utility in PeCa. Formalin-fixed, paraffin-embedded tumor tissue from therapy-naïve patients with invasive PeCa was used for tissue microarray (TMA) analysis. Immunohistochemical staining was performed to determine the expression of the proteins c-MET, PPARg, β-catenin, snail, survivin, and n-MYC. In total, 94 PeCa patients with available tumor tissue were included. The median age was 64.9 years. High-grade tumors were present in 23.4%, and high-risk HPV was detected in 25.5%. The median follow-up was 32.5 months. High expression of snail was associated with HPV-positive tumors. Expression of β-catenin was inversely associated with grading. In both univariate COX regression analysis and the log-rank test, an increased expression of PPARg and c-MET was predictive of inferior disease-specific survival (DSS). Moreover, in multivariate analysis, a higher expression of c-MET was independently associated with worse DSS. Blocking c-MET with cabozantinib and tivantinib induced a significant decrease in viability in the primary PeCa cell line UKF-PeC3 isolated from the tumor tissue as well as in cisplatin- and osimertinib-resistant sublines. Strikingly, a higher sensitivity to tivantinib could be detected in the latter, pointing to the promising option of utilizing this agent in the second-line treatment setting.

The Evolution of Immune Checkpoint Inhibitors in Advanced Urothelial Carcinoma

Simple Summary

Urothelial carcinoma is an aggressive cancer with a high risk of metastatic progression. Chemotherapy plays a key role in the management of metastatic urothelial carcinoma, with, however, no possibility of cure. Immune checkpoint inhibitors have significantly improved the outcomes of patients, delaying progression of disease and improving quality of life. However, many questions remain concerning the optimal use of immunotherapy in urothelial carcinoma: When to start? Which biomarker of sensitivity/resistance to use? Which of the available options will increase the efficacy of immune checkpoint inhibitors? We review the mechanisms of immune checkpoint inhibitors as well as the current management of patients with metastatic urothelial carcinoma in the era of immunotherapy.

Abstract

Urothelial carcinoma is an aggressive cancer and development of metastases remains a challenge for clinicians. Immune checkpoint inhibitors (ICIs) are significantly improving the outcomes of patients with metastatic urothelial cancer (mUC). These agents were first used in monotherapy after failure of platinum-based chemotherapy, but different strategies explored the optimal use of ICIs in a first-line metastatic setting. The “maintenance” strategy consists of the introduction of ICIs in patients who experienced benefit from first-line chemotherapy in a metastatic setting. This allows an earlier use of ICIs, without waiting for disease progression. We review the optimal management of mUC in the era of ICIs, based on the key clinical messages arising from the pivotal trials.

Current and emerging role of sacituzumab govitecan in the management of urothelial carcinoma

INTRODUCTION

Despite rapid advances in the treatment landscape of urothelial cancer, there is a substantial unmet need for safe and effective therapies for patients with locally advanced and metastatic urothelial cancer. Sacituzumab govitecan (SG) is an antibody-drug conjugate, consisting of a Trop-2 directed monoclonal antibody linked to SN-38, the active metabolite of irinotecan. Trop-2 is a glycoprotein overexpressed in various carcinomas, including urothelial carcinomas.

AREAS COVERED

We review the available data on SG, including mechanism of action, pharmacology, efficacy, safety, and clinical studies regarding locally advanced or metastatic urothelial cancer.

EXPERT OPINION

SG performed well in the TROPHY-U-01 phase II trial with an objective response rate of 27%. The most common adverse effects were diarrhea, nausea, fatigue, alopecia, and neutropenia, with the most common grade ≥ 3 treatment-related AEs being neutropenia, leukopenia, anemia, diarrhea, and febrile neutropenia. However, these effects were managed effectively with supportive care. SG currently has an accelerated approval for patients with locally advanced or metastatic urothelial cancer who have received platinum-based chemotherapy and either programmed cell death receptor-1 (PD-1) or programmed death-ligand 1 (PD-L1) inhibitor. Several studies are evaluating SG in urothelial cancers as single-agent or in combination with other agents.

Improving the role of immune checkpoint inhibitors in the management of advanced urothelial carcinoma, where do we stand?

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Immune checkpoint inhibitors improve outcome in metastatic urothelial carcinoma.

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Maintenance strategy involves early use of avelumab after efficient chemotherapy.

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Patients with no progression on chemotherapy should receive maintenance avelumab.

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There is no place for PD-L1 testing when considering maintenance strategy.

Immune checkpoint inhibitors (ICIs) have significantly improved the outcome of patients with metastatic urothelial cancer (mUC). If these agents were first used in monotherapy after failure of platinum-based chemotherapy, new strategies have been evaluated in the last years, including association of ICIs, ICI plus chemotherapy association or maintenance therapy. This maintenance concept allows a better management of mUC, which is particularly interesting in cisplatin-ineligible patients.

This paper aims to review the current knowledge of ICIs in urothelial carcinoma as well as the new indications of these agents in mUC.

Antibody-drug conjugates: Smart chemotherapy delivery across tumor histologies

As distinct cancer biomarkers have been discovered in recent years, a need to reclassify tumors by more than their histology has been proposed, and therapies are now tailored to treat cancers based on specific molecular aberrations and immunologic markers. In fact, multiple histology-agnostic therapies are currently adopted in clinical practice for treating patients regardless of their tumor site of origin. In parallel with this new model for drug development, in the past few years, several novel antibody-drug conjugates (ADCs) have been approved to treat solid tumors, benefiting from engineering improvements in the conjugation process and the introduction of novel linkers and payloads. With the recognition that numerous surface targets are expressed across various cancer histologies, alongside the remarkable activity of modern ADCs, this drug class has been increasingly evaluated as suitable for a histology-agnostic expansion of indication. For illustration, the anti-HER2 ADC trastuzumab deruxtecan has demonstrated compelling activity in HER2-overexpressing breast, gastric, colorectal, and lung cancer. Examples of additional novel and potentially histology-agnostic ADC targets include trophoblast cell-surface antigen 2 (Trop-2) and nectin-4, among others. In the current review article, the authors summarize the current approvals of ADCs by the US Food and Drug Administration focusing on solid tumors and discuss the challenges and opportunities posed by the multihistological expansion of ADCs.

Antibody-Drug Conjugates in Urothelial Carcinoma: A New Therapeutic Opportunity Moves from Bench to Bedside

Significant progress has been achieved over the last decades in understanding the biology and mechanisms of tumor progression in urothelial carcinoma (UC). Although the therapeutic landscape has dramatically changed in recent years with the introduction of immune checkpoint inhibitors, advanced UC is still associated with rapidly progressing disease and poor survival. The increasing knowledge of the pathogenesis and molecular pathways underlying cancer development and progression is leading the introduction of target therapies, such as the recently approved FGFR inhibitor Erdafitinib, or the anti-nectin 4 antibody drug-conjugate Enfortumab vedotin. Antibody drug conjugates represent an innovative therapeutic approach that allows the combination of a tar get-specific monoclonal antibody covalently conjugated via a linker to a cytotoxic agent (payload). UC is a perfect candidate for this therapeutic approach since it is particularly enriched in antigen expression on its surface and each specific antigen can represent a potential therapeutic target. In this review we summarize the mechanism of action of ADCs, their applications in localized and metastatic UC, the main mechanisms of resistance, and future perspectives for their use in clinical practice.

Antibody-drug conjugates: Resurgent anticancer agents with multi-targeted therapeutic potential

Antibody-drug conjugates (ADCs) constitute a relatively new group of anticancer agents, whose first appearance took place about two decades ago, but a renewed interest occurred in recent years, following the success of anti-cancer immunotherapy with monoclonal antibodies. Indeed, an ADC combines the selectivity of a monoclonal antibody with the cell killing properties of a chemotherapeutic agent (payload), joined together through an appropriate linker. The antibody moiety targets a specific cell surface antigen expressed by tumor cells and/or cells of the tumor microenvironment and acts as a carrier that delivers the cytotoxic payload within the tumor mass. Despite advantages in terms of selectivity and potency, the development of ADCs is not devoid of challenges, due to: i) low tumor selectivity when the target antigens are not exclusively expressed by cancer cells; ii) premature release of the cytotoxic drug into the bloodstream as a consequence of linker instability; iii) development of tumor resistance mechanisms to the payload. All these factors may result in lack of efficacy and/or in no safety improvement compared to unconjugated cytotoxic agents. Nevertheless, the development of antibodies engineered to remain inert until activated in the tumor (e.g., antibodies activated proteolytically after internalization or by the acidic conditions of the tumor microenvironment) together with the discovery of innovative targets and cytotoxic or immunomodulatory payloads, have allowed the design of next-generation ADCs that are expected to possess improved therapeutic properties. This review provides an overview of approved ADCs, with related advantages and limitations, and of novel targets exploited by ADCs that are presently under clinical investigation.

Bone metastases from urothelial carcinoma. The dark side of the moon

Bone metastases are common in genitourinary cancers, but they are underreported and not well researched. Synchronous bone metastases occur in 1.39-5.5% of bladder cancer patients, while 30-40% of cases are metachronous. Bone morphogenetic proteins (BMPs) play a key role in regulating proliferation, migration and invasion of tumor cells in bone microenvironment of bone metastases from metastatic urothelial carcinoma (mUC). Bone metastases represent a poor prognostic factor due to high morbidity and mortality correlated to skeletal-related events (SREs). The incidence rate of SREs in bladder, renal pelvis, and ureteral cancer varies from 39 to 68%. Radiotherapy is the most frequent treatment for SREs. The early use of bone targeted therapies (BTT), zoledronic acid and denosumab, improves SREs incidence and morbidity and it seems to improve overall survival (OS). To date, several new agents (immunotherapy and targeted drugs) demonstrated efficacy in mUC. However, subgroup analysis for bone metastases is often not available, due to difficulties in analysing bone samples, non-RECIST lesions and delay in systemic treatment due to SREs that limit the enrolment of bone mUC patients in clinical trials. Larger solid tumor studies that included UC patients are the main source of data for the management of mUC patients with bone metastases. For these patients, multidisciplinary approach should be preferred, involving orthopaedics, radiotherapists and rehabilitation to improve outcome and quality of life. New prospective trials should characterize clinical and molecular features of patients with bone metastases and the impact of new drugs on this poor prognostic metastatic site.

Repeat Treatment of Patients With Advanced Urothelial Carcinoma With Immune Checkpoint Inhibitors Following Prior Progression on a Checkpoint Inhibitor Regimen: A Case Series

INTRODUCTION

Immune checkpoint inhibitors (ICIs) have become one of the mainstays of systemic therapy for advanced urothelial carcinoma (aUC). Increasingly ICIs are also being utilized earlier in the course of UC treatment. Limited data are available regarding ICI treatment efficacy in aUC patients who have progressed on prior ICI regimens. This case series aims to address this knowledge gap.

PATIENTS AND METHODS

We identified all aUC patients treated with ICI or combination following prior progression on another ICI regimen at two academic institutions. Patient demographic, clinicopathologic and treatment data were retrospectively collected from chart review at each site. Best response to ICI treatment was defined by investigator at each site.

RESULTS

Among 7 patients with aUC who received ICI treatment following prior progression on a different ICI regimen, radiographic response to the second ICI regimen was observed in only 1 patient (14%) treated with combination of pembrolizumab/enfortumab vedotin.

CONCLUSION

Efficacy of ICI treatment in patients who previously progressed on another ICI regimen appears limited. These observations should be validated in larger cohorts, as it is anticipated that this clinical scenario will become more common in the future.

Synthesis and evaluation of highly releasable and structurally stable antibody-SN-38-conjugates

Camptothecins, traditional chemotherapy drugs, have been clinically used in antibody-drug conjugates (ADCs), which refreshes the recognition that ADCs preferably incorporate highly potent payloads. However, SN-38, active metabolite of irinotecan from camptothecins, tended to be incorporated into ADCs with an unstable acid sensitive bond, not with the widely used Cathepsin B (CTSB) sensitive bond, which may pose the risk of off-target. Herein, we reported a novel strategy to construct highly releasable and structurally stable SN-38-conjugates, in which CTSB linkers directly connected to the 10-OH group through ether bond, not to the common 20-OH group of lactones of SN-38. In this paper, rapid release of SN-38 was skillfully demonstrated by utilizing the fluorescence properties of SN-38. The SN-38-ether-ADC displayed highly stable serum stability with the half-life over 10 days. Moreover, the drug-antibody-ratio (DAR) of ADC could be elevated to 7.1 through the introduction of polyethylene glycol (PEG) moieties without aggregation. The optimized ADC exhibited potent in vitro activities up to 5.5 nM, comparable to SN-38. Moreover, this ADC group significantly delayed tumor growth in vivo. In conclusion, the novel strategy has the potential to promote the development of SN38-ADCs and enrich the conjugation approaches for hydroxyl-bearing payloads.

Efficacy of enfortumab vedotin in advanced urothelial cancer: Analysis from the Urothelial Cancer Network to Investigate Therapeutic Experiences (UNITE) study

BACKGROUND

Enfortumab vedotin (EV) is a novel antibody-drug conjugate approved for advanced urothelial cancer (aUC) refractory to prior therapy. In the Urothelial Cancer Network to Investigate Therapeutic Experiences (UNITE) study, the authors looked at the experience with EV in patient subsets of interest for which activity had not been well defined in clinical trials.

METHODS

UNITE was a retrospective study of patients with aUC treated with recently approved agents. This initial analysis focused on patients treated with EV. Patient data were abstracted from chart reviews by investigators at each site. The observed response rate (ORR) was investigator-assessed for patients with at least 1 post-baseline scan or clear evidence of clinical progression. ORRs were compared across subsets of interest for patients treated with EV monotherapy.

RESULTS

The initial UNITE analysis included 304 patients from 16 institutions; 260 of these patients were treated with EV monotherapy and included in the analyses. In the monotherapy cohort, the ORR was 52%, and it was >40% in all reported subsets of interest, including patients with comorbidities previously excluded from clinical trials (baseline renal impairment, diabetes, and neuropathy) and patients with fibroblast growth factor receptor 3 (FGFR3) alterations. Progression-free survival and overall survival were 6.8 and 14.4 months, respectively. Patients with a pure urothelial histology had a higher ORR than patients with a variant histology component (58% vs 42%; P = .06).

CONCLUSIONS

In a large retrospective cohort, responses to EV monotherapy were consistent with data previously reported in clinical trials and were also observed in various patient subsets, including patients with variant histology, patients with FGFR3 alterations, and patients previously excluded from clinical trials with an estimated glomerular filtration rate < 30 mL/min and significant comorbidities.

LAY SUMMARY

Enfortumab vedotin, approved by the Food and Drug Administration in 2019, is an important new drug for the treatment of patients with advanced bladder cancer. This study looks at the effectiveness of enfortumab vedotin as it has been used at multiple centers since approval, and focuses on important patient populations previously excluded from clinical trials. These populations include patients with decreased kidney function, diabetes, and important mutations. Enfortumab vedotin is effective for treating these patients. Previously reported clinical trial data have been replicated in this real-world setting, and support the use of this drug in broader patient populations.

Avelumab as neoadjuvant therapy in patients with urothelial non-metastatic muscle invasive bladder cancer: a multicenter, randomized, non-comparative, phase II study (Oncodistinct 004 - AURA trial)

Introduction

Cisplatin-based neoadjuvant chemotherapy (NAC) followed by surgery is the standard treatment for patients with non-metastatic muscle invasive bladder cancer (MIBC). Unfortunately, many patients are not candidates to receive cisplatin due to renal impairment. Additionally, no predictive biomarkers for pathological complete response (pCR) are currently validated in clinical practice. Studies evaluating immune checkpoint inhibitors in the peri-operative setting are emerging with promising results. Clinical trials are clearly required in the neoadjuvant setting in order to improve therapeutic strategies.

Methods and analysis

Oncodistinct 004 – AURA is an ongoing multicenter phase II randomized trial assessing the efficacy and safety of avelumab single-agent or combined to different NAC regimens in patients with non-metastatic MIBC. Patients are enrolled in two distinct cohorts according to their eligibility to receive cisplatin-based NAC. In the cisplatin eligible cohort, patients are randomized in a 1:1 fashion to receive avelumab combined with cisplatin-gemcitabine or with dose-dense methotrexate-vinblastine-doxorubicin-cisplatin. In the cisplatin ineligible cohort, patients are randomized at a 1:1 ratio to paclitaxel-gemcitabine associated to avelumab or avelumab alone. Primary endpoint is pCR. Secondary endpoints are pathological response and safety.

Ethics and dissemination

The study is approved by ethics committee from all participating centers. All participants provide informed consent prior inclusion to the study. Once completed, results will be published in peer-reviewed journals.

Trial registration number

ClinicalTrials.gov (NCT03674424).

A New Kid on the Block: Sacituzumab Govitecan for the Treatment of Breast Cancer and Other Solid Tumors

Human trophoblast cell-surface antigen-2 (Trop-2) is a membrane glycoprotein involved in cell proliferation and motility, frequently overexpressed in epithelial tumors. Thus, it represents an attractive target for anticancer therapies. Sacituzumab govitecan (SG) is a third-generation antibody-drug conjugate, consisting of an anti-Trop-2 monoclonal antibody (hRS7), a hydrolyzable linker, and a cytotoxin (SN38), which inhibits topoisomerase 1. Specific pharmacological features, such as the high antibody to payload ratio, the ultra-toxic nature of SN38, and the capacity to kill surrounding tumor cells (the bystander effect), make SG a very promising drug for cancer treatment. Indeed, unprecedented results have been observed with SG in patients with heavily pretreated advanced triple-negative breast cancer and urothelial carcinomas, and the drug has already received approval for these indications. These results are coupled with a manageable toxicity profile, with neutropenia and diarrhea as the most frequent adverse events, mainly of grades 1-2. While several trials are exploring SG activity in different tumor types and settings, potential biomarkers of response are under investigation. Among these, Trop-2 overexpression and the presence of BRCA1/2 mutations seem to be the most promising. We review the available literature concerning SG, with a focus on its toxicity spectrum and possible biomarkers of its response.

The emerging treatment landscape of advanced urothelial carcinoma

PURPOSE OF REVIEW

Urothelial carcinoma (UC) is one of the most common malignancies in the Western world. Historically, patients with advanced disease have had a poor prognosis and progress within months of completing upfront platinum-based chemotherapy. In the last two years, the treatment landscape for metastatic UC (mUC) has significantly shifted with the emergence of contemporary immunotherapy and targeted agents. The purpose of this review is to highlight the current and emerging systemic treatment options for mUC of the bladder.

RECENT FINDINGS

PD-1/PD-L1 immune checkpoint inhibitors (ICIs) have demonstrated activity in the postplatinum and platinum-ineligible settings. Additionally, they have become a standard maintenance treatment option after avelumab demonstrated increased overall survival in patients with stable disease or better after first line platinum-based chemotherapy. Novel targeted therapies and antibody-drug conjugates (ADCs) have been granted Food and Drug Administration approval for subsequent line therapy based on promising results in phase II and III trials.

SUMMARY

There has been a considerable increase in the variety of effective therapies for mUC, including the utility of ICIs, novel targeted agents, and ADCs. Platinum-based chemotherapy remains an effective first-line option. As the role of novel therapies continues to shift toward earlier in the disease course, there remains an important need to develop feasible, globally accessible predictive biomarkers that can aid in patient selection and inform sequencing of therapeutic options.

Efficacy of Platinum Rechallenge in Metastatic Urothelial Carcinoma After Previous Platinum-Based Chemotherapy for Metastatic Disease

BACKGROUND

Fit patients with metastatic urothelial carcinoma (mUC) receive first-line platinum-based combination chemotherapy (fPBC) as standard of care and may receive additional later-line chemotherapy after progression. Our study compares outcomes with subsequent platinum-based chemotherapy (sPBC) versus subsequent non-platinum-based chemotherapy (sNPBC).

MATERIALS AND METHODS

Patients from 27 international centers in the Retrospective International Study of Cancers of the Urothelium (RISC) who received fPBC for mUC and at least two cycles of subsequent chemotherapy were included in this study. A multivariable Cox proportional hazards model compared overall survival (OS) and progression-free survival (PFS).

RESULTS

One hundred thirty-five patients received sPBC and 161 received sNPBC. Baseline characteristics were similar between groups, except patients who received sPBC had higher baseline hemoglobin, higher disease control rate with fPBC, and longer time since fPBC. OS was superior in the sPBC group (median 7.9 vs 5.5 months) in a model adjusting for comorbidity burden, performance status, liver metastases, number of fPBC cycles received, best response to fPBC, and time since fPBC (hazard ratio, 0.72; 95% confidence interval, 0.53-0.98; p = .035). There was no difference in PFS. More patients in the sPBC group achieved disease control than in the sNPBC group (57.4% vs 44.8%; p = .041). Factors associated with achieving disease control in the sPBC group but not the sNPBC group included longer time since fPBC, achieving disease control with fPBC, and absence of liver metastases.

CONCLUSION

After receiving fPBC for mUC, patients who received sPBC had better OS and disease control. This may help inform the choice of subsequent chemotherapy in patients with mUC.

IMPLICATIONS FOR PRACTICE

Patients with progressive metastatic urothelial carcinoma after first-line platinum-based combination chemotherapy may now receive immuno-oncology agents, erdafitinib, enfortumab vedotin, or sacituzumab govitecan-hziy; however, those ineligible for these later-line therapies or who progress after receiving them may be considered for subsequent chemotherapy. In this retrospective study of 296 patients, survival outcomes and disease control rates were better in those receiving subsequent platinum-based rechallenge compared with non-platinum-based chemotherapy, suggesting that patients should receive platinum rechallenge if clinically able. Disease control with platinum rechallenge was more likely with prior first-line platinum having achieved disease control, longer time since first-line platinum, and absence of liver metastases.

Different Responses to Neoadjuvant Chemotherapy in Urothelial Carcinoma Molecular Subtypes

BACKGROUND

For muscle-invasive bladder cancer (MIBC), no tissue biomarkers are available for clinical use to predict response to neoadjuvant chemotherapy.

OBJECTIVE

To investigate how molecular subtypes impact pathological response and survival in patients receiving preoperative cisplatin-based chemotherapy.

DESIGN, SETTING, AND PARTICIPANTS

Classification of a retrospective cohort of 149 patients was performed by tumor transcriptomic profiling and immunostaining. A cohort treated with radical cystectomy alone and public data sets were used for comparison and external validation.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Complete pathological response in the cystectomy specimen (ypT0N0) and survival were compared in predefined molecular subtypes. Differential gene expression and chemotherapy response were explored beyond molecular subtypes.

RESULTS AND LIMITATIONS

Patients with genomically unstable (GU) and urothelial-like (Uro) tumors had higher proportions of complete pathological response (16/31 [52%] and 17/54 [31%]), versus five out of 24 (21%) with the basal/squamous (Ba/Sq) subtype following neoadjuvant chemotherapy and radical cystectomy. Molecular subtype was independently associated with improved survival for patients with GU tumors (hazard ratio [HR] 0.29, 95% confidence interval [CI]: 0.11-0.79) and UroC tumors (HR 0.37, 95% CI: 0.14-0.94) compared with Ba/Sq tumors, adjusting for clinical stage. In addition, expression of the gene coding for osteopontin (SPP1) showed a subtype-dependent effect on chemotherapy response.

CONCLUSIONS

Urothelial cancer of the luminal-like (GU and Uro) subtypes is more responsive to cisplatin-based neoadjuvant chemotherapy. A second-generation of subtype-specific biomarkers, for example, SPP1, may be a way forward to develop a more precision-based treatment approach for neoadjuvant chemotherapy in MIBC.

PATIENT SUMMARY

This study shows that tumor classification by gene expression profiling and molecular subtyping can identify patients who are more likely to benefit from chemotherapy before radical cystectomy for muscle-invasive bladder cancer. Together with other markers for response, molecular subtypes could have a role in selective administration of such chemotherapy.

The 2021 Updated European Association of Urology Guidelines on Metastatic Urothelial Carcinoma

CONTEXT

Treatment of metastatic urothelial carcinoma is currently undergoing a rapid evolution.

OBJECTIVE

This overview presents the updated European Association of Urology (EAU) guidelines for metastatic urothelial carcinoma.

EVIDENCE ACQUISITION

A comprehensive scoping exercise covering the topic of metastatic urothelial carcinoma is performed annually by the Guidelines Panel. Databases covered by the search included Medline, EMBASE, and the Cochrane Libraries, resulting in yearly guideline updates.

EVIDENCE SYNTHESIS

Platinum-based chemotherapy is the recommended first-line standard therapy for all patients fit to receive either cisplatin or carboplatin. Patients positive for programmed death ligand 1 (PD-L1) and ineligible for cisplatin may receive immunotherapy (atezolizumab or pembrolizumab). In case of nonprogressive disease on platinum-based chemotherapy, subsequent maintenance immunotherapy (avelumab) is recommended. For patients without maintenance therapy, the recommended second-line regimen is immunotherapy (pembrolizumab). Later-line treatment has undergone recent advances: the antibody-drug conjugate enfortumab vedotin demonstrated improved overall survival and the fibroblast growth factor receptor (FGFR) inhibitor erdafitinib appears active in case of FGFR3 alterations.

CONCLUSIONS

This 2021 update of the EAU guideline provides detailed and contemporary information on the treatment of metastatic urothelial carcinoma for incorporation into clinical practice.

PATIENT SUMMARY

In recent years, several new treatment options have been introduced for patients with metastatic urothelial cancer (including bladder cancer and cancer of the upper urinary tract and urethra). These include immunotherapy and targeted treatments. This updated guideline informs clinicians and patients about optimal tailoring of treatment of affected patients.

Synergistic antitumor activity of pan-PI3K inhibition and immune checkpoint blockade in bladder cancer

Background

Immune checkpoint blockade (ICB) induces durable response in approximately 20% of patients with advanced bladder urothelial cancer (aUC). Over 50% of aUCs harbor genomic alterations along the phosphoinositide 3-kinase (PI3K) pathway. The goal of this project was to determine the synergistic effects and mechanisms of action of PI3K inhibition and ICB combination in aUC.

Methods

Alterations affecting the PI3K pathway were examined in The Cancer Genome Atlas (TCGA) and the Cancer Dependency Map databases. Human and mouse cells with Pten deletion were used for in vitro studies. C57BL/6 mice carrying syngeneic tumors were used to determine in vivo activity, mechanisms of action and secondary resistance of pan-PI3K inhibition, ICB and combination.

Results

Alterations along the PI3K pathway occurred in 57% of aUCs in TCGA. CRISPR (clustered regularly interspaced short palindromic repeats) knockout of PIK3CA induced pronounced inhibition of cell proliferation (p=0.0046). PI3K inhibition suppressed cancer cell growth, migration and colony formation in vitro. Pan-PI3K inhibition, antiprogrammed death 1 (aPD1) therapy and combination improved the overall survival (OS) of syngeneic mice with PTEN-deleted tumors from 27 days of the control to 48, 37, and 65 days, respectively. In mice with tumors not containing a PI3K pathway alteration, OS was prolonged by the combination but not single treatments. Pan-PI3K inhibition significantly upregulated CD80, CD86, MHC-I, and MHC-II in dendritic cells, and downregulated the transforming growth factor beta pathway with a false discovery rate-adjusted q value of 0.001. Interferon alpha response was significantly upregulated with aPD1 therapy (q value: <0.001) and combination (q value: 0.027). Compared with the control, combination treatment increased CD8⁺ T-cell infiltration (p=0.005), decreased T_reg-cell infiltration (p=0.036), and upregulated the expression of multiple immunostimulatory cytokines and granzyme B (p<0.01). Secondary resistance was associated with upregulation of the mammalian target of rapamycin (mTOR) pathway and multiple Sprr family genes.

Conclusions

The combination Pan-PI3K inhibition and ICB has significant antitumor effects in aUC with or without activated PI3K pathway and warrants further clinical investigation. This combination creates an immunostimulatory tumor milieu. Secondary resistance is associated with upregulation of the mTOR pathway and Sprr family genes.

A Molecular Inquiry into the Role of Antibody-Drug Conjugates in Bacillus Calmette-Guérin-exposed Non-muscle-invasive Bladder Cancer

The treatment landscape for advanced urothelial cancer has changed dramatically owing to the US Food and Drug Administration approval and introduction of antibody-drug conjugates (ADCs), including enfortumab vedotin and sacituzumab govitecan. Efforts have begun to use these therapies in earlier disease states, specifically bacillus Calmette-Guérin (BCG)-unresponsive non-muscle-invasive bladder cancer (NMIBC). We assessed gene expression associated with these newly approved therapies in a novel cohort of treatment-naïve NMIBC tumors before and after BCG therapy. Multiple genes, including Nectin-4, Trop-2, and Her-2, exhibited increased expression after BCG therapy compared to baseline. However, few of the tumors with increased expression of ADC targets also exhibited increased PD-L1/PD-1 expression. Taken together, these data demonstrate the heterogeneous genomic landscape of BCG-exposed NMIBC, and provide evidence supporting the evaluation of ADCs in NMIBC. PATIENT SUMMARY: We evaluated the potential role of targeted therapies that have been approved in the USA for advanced non-muscle-invasive bladder cancer (NMIBC) that has recurred after treatment with bacillus Calmette-Guérin (BCG). By assessing levels of specific genes and proteins linked to the targeted therapies, we demonstrate that there is rationale for further evaluation of these therapies in NMIBC.

Emerging strategies for the improvement of chemotherapy in bladder cancer: Current knowledge and future perspectives

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The response of chemotherapy and prognosis in bladder cancer is unsatisfied.

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Immunotherapy, targeted therapy, and ADC improve the efficacy of chemotherapy.

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Emerging targets in cancer cells and TME spawned novel preclinical agents.

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Novel drug delivery, such as nanotechnology, enhances effects of chemotherapeutics.

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The organoid and PDX model are promising to screen and evaluate the target therapy.

Background

Chemotherapy is a first-line treatment for advanced and metastatic bladder cancer, but the unsatisfactory objective response rate to this treatment yields poor 5-year patient survival. Only PD-1/PD-L1-based immune checkpoint inhibitors, FGFR3 inhibitors and antibody-drug conjugates are approved by the FDA to be used in bladder cancer, mainly for platinum-refractory or platinum-ineligible locally advanced or metastatic urothelial carcinoma. Emerging studies indicate that the combination of targeted therapy and chemotherapy shows better efficacy than targeted therapy or chemotherapy alone. Newly identified targets in cancer cells and various functions of the tumour microenvironment have spawned novel agents and regimens, which give impetus to sensitizing chemotherapy in the bladder cancer setting.

Aim of Review

This review aims to present the current evidence for potentiating the efficacy of chemotherapy in bladder cancer. We focus on combining chemotherapy with other treatments as follows: targeted therapy, including immunotherapy and antibody-drug conjugates in clinic; novel targeted drugs and nanoparticles in preclinical models and potential targets that may contribute to chemosensitivity in future clinical practice. The prospect of precision therapy is also discussed in bladder cancer.

Key Scientific Concepts of Review

Combining chemotherapy drugs with immune checkpoint inhibitors, antibody-drug conjugates and VEGF inhibitors potentially elevates the response rate and survival. Novel targets, including cancer stem cells, DNA damage repair, antiapoptosis, drug metabolism and the tumour microenvironment, contribute to chemosensitization. Gene alteration-based drug selection and patient-derived xenograft- and organoid-based drug validation are the future for precision therapy.

Metastatic Urothelial Cancer: a rapidly changing treatment landscape

Despite significant progress, metastatic urothelial cancer remains an incurable condition with a limited life expectancy. Platinum-based chemotherapy is still the mainstay of treatment for metastatic disease, but immunotherapy, antibody drug conjugates, and targeted agents have shown encouraging results in several recent practice changing trials. In this review, we discuss the standard of care, recent therapeutic advances, ongoing clinical trials, and future perspectives in metastatic urothelial carcinoma.

An Insight into FDA Approved Antibody-Drug Conjugates for Cancer Therapy

The large number of emerging antibody-drug conjugates (ADCs) for cancer therapy has resulted in a significant market 'boom', garnering worldwide attention. Despite ADCs presenting huge challenges to researchers, particularly regarding the identification of a suitable combination of antibody, linker, and payload, as of September 2021, 11 ADCs have been granted FDA approval, with eight of these approved since 2017 alone. Optimism for this therapeutic approach is clear, despite the COVID-19 pandemic, 2020 was a landmark year for deals and partnerships in the ADC arena, suggesting that there remains significant interest from Big Pharma. Herein we review the enthusiasm for ADCs by focusing on the features of those approved by the FDA, and offer some thoughts as to where the field is headed.

Genome-wide screening for the G-protein-coupled receptor (GPCR) pathway-related therapeutic gene RGS19 (regulator of G protein signaling 19) in bladder cancer

Bladder cancer is one of the most severe genitourinary cancers, causing high morbidity worldwide. However, the underlying molecular mechanism is not clear, and it is urgent to find target genes for treatment. G-protein-coupled receptors are currently a target of high interest for drug design. Thus, we aimed to identify a target gene-related to G-protein-coupled receptors for therapy. We used The Cancer Genome Atlas (TCGA) and DepMap databases to obtain the expression and clinical data of RGS19. The results showed that RGS19 was overexpressed in a wide range of tumor, especially bladder cancer. We also explored its effect on various types of cancer. High expression of RGS19 was also shown to be significantly associated with poor prognosis. Cell models were constructed for cell cycle detection. shRGS19 can halt the cell cycle at a polyploid point. RGS19 is a G-protein-coupled receptor signaling pathway-related gene with a significant effect on survival. We chose RGS19 as a therapeutic target gene in bladder cancer. The drug GSK1070916 was found to inhibit the effect of RGS19 via cell rescue experiments in vitro.

Immune Checkpoint Inhibitors in Urothelial Bladder Cancer: State of the Art and Future Perspectives

Bladder cancer (BC) is the most common malignancy of the genitourinary tract, with high morbidity and mortality rates. Until recently, the treatment of locally advanced or metastatic urothelial BC was based on the use of chemotherapy alone. Since 2016, five immune checkpoint inhibitors (ICIs) have been approved by the Food and Drug Administration (FDA) in different settings, i.e., first-line, maintenance and second-line treatment, while several trials are still ongoing in the perioperative context. Lately, pembrolizumab, a programmed death-1 (PD-1) inhibitor, has been approved for Bacillus Calmette-Guérin (BCG)-unresponsive high-risk non-muscle invasive bladder cancer (NMIBC), using immunotherapy at an early stage of the disease. This review investigates the current state and future perspectives of immunotherapy in BC, focusing on the rationale and results of combining immunotherapy with other therapeutic strategies.

Outcomes of metastatic urothelial carcinoma following discontinuation of enfortumab-vedotin

BACKGROUND

Enfortumab vedotin (EV) is approved to treat metastatic urothelial carcinoma (mUC) following platinum and PD1/L1 inhibitors. Since the outcomes and patterns of therapy of patients following discontinuation of EV are unknown, we conducted a retrospective study to assess this issue.

METHODS

Data were retrospectively obtained from patients with mUC following discontinuation of EV after prior platinum-based chemotherapy and PD1/L1 inhibitors. Objective response rate (ORR) was evaluated in those who received therapy post-EV. Statistical analyses were performed to describe the overall survival (OS) and compare patient characteristics and outcomes of those who did or did not receive treatment post-EV.

RESULTS

Data were available for 63 patients from 6 institutions: 46 (73%) were male and median age was 68 years (range 43-83). The median OS was 32 weeks. Thirty-two patients (51%) received therapy after EV. The OS of those who did vs. did not receive post-EV therapy was significantly different (median 43.1 vs. 16.9 weeks, P = .015). Longer duration of prior EV therapy was associated with receipt of post-EV therapy (P = .0437) as well as OS in both the treated (P = .045) and untreated groups (P = .012). Objective response was observed in 3 of 32 patients (9.4%) who received therapy post-EV.

CONCLUSION

Outcomes of patients with mUC following discontinuation of EV are dismal and only 51% received therapy after discontinuation of EV. This study identifies benchmarks for the interpretation of activity of new agents following EV and raises the hypothesis for duration of EV as a potential prognostic factor following discontinuation of EV.

Autocrine signaling by receptor tyrosine kinases in urothelial carcinoma of the bladder

Comprehensive characterizations of bladder cancer (BCa) have established molecular phenotype classes with distinct alterations and survival trends. Extending these studies within the tyrosine kinase (TK) family to identify disease drivers could improve our use of TK inhibitors to treat specific patient groups or individuals. We examined the expression distribution of TKs as a class (n = 89) in The Cancer Genome Atlas (TCGA) muscle invasive BCa data set (n >400). Patient profiles of potentially oncogenic alterations (overexpression and/or amplification) clustered TKs into 3 groups; alterations of group 1 and 3 TKs were associated with significantly worse patient survival relative to those without alterations. Many TK pathways induce epithelial-to-mesenchymal transition (EMT), which promotes tumor invasiveness and metastasis. Overexpression and/or amplification among 9 EMT transcriptional activators occurred in 43% of TCGA cases. Co-occurring alterations of TKs and EMT transcriptional activators involved most group 1 TKs; 24% of these events were associated with significantly worse patient survival. Co-occurring alterations of receptor TKs and their cognate ligands occurred in 16% of TCGA cases and several BCa-derived cell lines. Suppression of GAS6, MST1 or CSF1, or their respective receptors (AXL, MST1R and CSF1R), in BCa cell lines was associated with decreased receptor activation, cell migration, cell proliferation and anchorage independent cell growth. These studies reveal the patterns and prevalence of potentially oncogenic TK pathway-related alterations in BCa and identify specific alterations associated with reduced BCa patient survival. Detection of these features in BCa patients could better inform TK inhibitor use and improve clinical outcomes.