Management of metastatic urothelial carcinoma: Current approach, emerging agents, and future perspectives

Metastatic urothelial carcinoma (mUC) is a lethal disease for which platinum-based chemotherapy represents the standard of care; however, long-term survival is achieved only in a minority of patients. Recently, along with important advances in the comprehension of the biology of this disease, the treatment paradigm of mUC has undergone a rapid expansion with the approval of several immune-checkpoint inhibitors (ICIs) and targeted agents in both first- and second-line settings. Cisplatin-based chemotherapy remains the backbone of first-therapy for mUC; nevertheless, for those patients who do not progress after the full course of first-line chemotherapy, maintenance treatment with the anti-PD-L1 avelumab showed to prolong overall survival compared observation alone. Moreover, the disappointing results of chemotherapy in pre-treated patients have led to the investigation and the subsequent approval of the anti-PD-1 pembrolizumab, which showed an unprecedented survival benefit when compared to second-line chemotherapy. Recently, target therapy with the antibody-drug conjugate (ADC) enfortumab vedotin, directed against Nectin-4, showed outstanding results in patients treated with both chemotherapy and immunotherapy. The FGFR inhibitor erdafitinib and sacituzumab govitecan, an ADC targeting Trop-2, demonstrated encouraging activity in phase II studies and are currently under investigation in randomized phase III trials. ICIs and targeted therapies also demonstrated promising results as first-line treatment of cisplatin-ineligible patients; randomized trials of ICIs alone or in combination with targeted agents are ongoing and may broaden the therapeutic armamentarium for this category of patients. In this review, we describe the current state of art for the treatment of mUC; in addition, we present the latest evidences from the most recent literature and congress presentations. Finally, we illustrate the key ongoing clinical trials, focusing on ICIs and target therapies.

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.

Salvage systemic therapy for metastatic urothelial carcinoma: an unmet clinical need

INTRODUCTION

Metastatic urothelial carcinoma (mUC) remains a fatal malignancy, despite the recent addition of immune check point inhibitors (ICIs), an FGFR inhibitor and an antibody-drug conjugate (ADC) to the therapeutic armamentarium. The survival rates are particularly dismal after first-line treatment failure, entailing an urgent need for more effective therapies. Advances in understanding biomarkers and identifying targetable molecules have broadened the pathways under investigation in mUC.

AREAS COVERED

This review summarizes mUC salvage therapy options, including chemotherapy, ICI, and novel promising agents, including targeted therapies, ADCs, cytotoxic agents and vaccines. For the literature review, a PubMed search and relevant data presented at international conferences were used.

EXPERT OPINION

The approval of ICIs, FGFR inhibitor erdafitinib and ADC enfortumab vedotin in the salvage setting has transformed the mUC landscape. Yet there are additional promising agents currently under study. Toxicities are observed with ADCs and FGFR inhibitors, but appear manageable in most patients. The molecular heterogeneity and complex tumor biology are challenging barriers for progress in the therapy of mUC. Advances in molecular profiling, defining validated predictive markers, rational combinations of agents and therapeutically actionable targets will help develop personalized compounds with higher efficacy and less toxicity with hopes to improve outcomes for mUC.

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.

The landscape of immunotherapy in metastatic urothelial carcinoma

PURPOSE OF REVIEW

This review provides an overview of clinical trials recently completed or currently ongoing evaluating the role of checkpoint blockade in metastatic urothelial carcinoma.

RECENT FINDINGS

In 2016, five immunotherapy agents were approved for metastatic urothelial carcinoma patients who had progressed on platinum-based chemotherapy All five agents evinced an approximately 20% overall response rate coupled with durability of response in a subset of these patients. Several putative predictive biomarkers of sensitivity to checkpoint blockade have been examined although which of these should be incorporated into standard practice is unclear. Moreover, as most patients do not respond to checkpoint blockade, research has focused on combination therapies in both the first-line and second-line settings.

SUMMARY

The durability of response and general tolerability of checkpoint blockade has transformed the treatment of metastatic urothelial carcinoma. However, only a minority of patients responds to single-agent therapy. Potential approaches to overcome this challenge include the incorporation of combination checkpoint blockade as well as chemotherapy and targeted agents.