Harnessing the immune system against cancer: current immunotherapy approaches and therapeutic targets

Cancer immunotherapy is a rapidly evolving concept that has been given the tag "fifth pillar" of cancer therapy while radiation therapy, chemotherapy, surgery and targeted therapy remain the other four pillars. This involves the stimulation of the immune system to control tumor growth and it specifically targets the neoplastic cells rather than the normal cells. Conventional chemotherapy has many limitations which include drug resistance, recurrence of cancer and severe adverse effects. Immunology has made major treatment breakthroughs for several cancers such as colorectal cancer, prostate cancer, breast cancer, lung cancer, liver cancer, kidney cancer, stomach cancer, acute lymphoblastic leukaemia etc. Currently, therapeutic strategies harnessing the immune system involve Checkpoint inhibitors, Chimeric antigen receptor T cells (CAR T cells), Monoclonal antibodies, Cancer vaccines, Cytokines, Radio-immunotherapy and Oncolytic virus therapy. The molecular characterization of several tumor antigens (TA) indicates that these TA can be utilized as promising candidates in cancer immunotherapy strategies. Here in this review, we highlight and summarize the different categories of emerging cancer immunotherapies along with the immunologically recognized tumor antigens involved in the tumor microenvironment.

Developing Precision Medicine for Bladder Cancer

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

Advances in the management of urothelial carcinoma: is immunotherapy the answer?

Introduction: Urothelial carcinoma (UC) is the second most common malignancy of the genitourinary system in the US, but mortality rate has not significantly improved despite advances in therapy. Over the past few years, the treatment landscape of non-muscle-invasive, muscle-invasive and metastatic UC (mUC) has evolved with the advent of immunotherapy.Areas covered: This paper summarizes current data and ongoing research into the use of immune checkpoint inhibitors (ICIs) in various settings of UC, including as maintenance therapy in chemotherapy-responsive mUC (with recent approval for avelumab in this setting) and as neoadjuvant and adjuvant therapies in localized and non-muscle-invasive disease. In addition, the authors review the combination of ICIs with chemotherapy, radiation and targeted therapies in an effort to increase response durability and efficacy.Expert opinion: While there has been a rapid expansion in clinical trials, platinum-based chemotherapy remains standard treatment in perioperative and first-line metastatic UC. The identification of biomarkers that can identify patients who will respond to ICIs has yielded conflicting results and has been largely non-generalizable to clinical practice. Further research into novel strategies and combinations with ICIs is needed to better characterize the role of immunotherapy in UC.

Emerging Targeted Therapy for Bladder Cancer

For the last decade, biology of urothelial tumorigenesis has been widely explored, helping to better understand the molecular pathways in urothelial carcinoma (UC). Until recently, no targeted therapies have been approved in UC. However, several new molecules have shown promising results in metastatic UC: fibroblast growth factor receptor inhibitors, conjugated antibodies, PARP inhibitors, and antiangiogenics. In this article, the authors review the targeted therapies that are being evaluated in bladder UC.

Sequential therapies for advanced urothelial cancer: Hope meets new challenges

A dramatic change in the treatment of advanced urothelial carcinomas (UC) occurred in the last 3 years, initially with the development of several check-point inhibitors, for second and first-line therapy. More recently, the approval of anti-FGFR (Fibroblast Growth Factor Receptor) and anti-nectin-4 inhibitors based on phase 2 studies in refractory disease, and the preliminary results of 3 randomized phase 3 trials combining chemotherapy and immunotherapy in first-line as well as using maintenance immunotherapy after chemotherapy induction, created a new paradigm in the treatment of metastatic disease. In this review, we will explore the new classes of agents and how they could be incorporated in the clinical practice as well as the results of recently presented randomized studies, guiding oncologists on the possible sequences for patients with advanced urothelial carcinoma.

Genomic profiling of Chinese patients with urothelial carcinoma

BACKGROUNDS

Urothelial carcinoma (UC) is the most common genitourinary malignancy in China. In this study, we surveyed the genomic features in Chinese UC patients and investigated the concordance of genetic alterations between circulating tumor DNA (ctDNA) in plasma and matched tumor tissue.

MATERIALS AND METHODS

A total of 112 UC patients were enrolled, of which 31 were upper tract UC (UTUC) and 81 were UC of bladder (UCB). Genomic alterations in 92 selected genes were analyzed by targeted next-generation sequencing.

RESULTS

In the study cohort, 94.64, 86.61 and 62.50% of patients were identified as having valid somatic, oncogenic and actionable somatic alterations, respectively. The most frequently altered genes included TP53, KMT2D, KDM6A, FAT4, FAT1, CREBBP and ARID1A. The higher prevalence of HRAS (22.0% vs 3.7%) and KMT2D (59.26% vs 34.57%) was identified in UTUC than in UCB. Comparisons of somatic alterations of UCB and UTUC between the study cohort and western cohorts revealed significant differences in mutant prevalence. Notably, 28.57, 17.86 and 47.32% of the cases harbored alterations in FGFRs, ERBBs and DNA damage repair genes, respectively. Furthermore, 75% of the patients carried non-benign germline variants, but only two (1.79%) were pathogenic. The overall concordance for genomic alterations in ctDNA and matched tumor tissue was 42.97% (0-100%). Notably, 47.25% of alterations detected in ctDNA were not detected in the matched tissue, and 54.14% of which were oncogenic mutations.

CONCLUSIONS

We found a unique genomic feature of Chinese UC patients. A reasonably good concordance of genomic features between ctDNA and tissue samples were identified.

Novel Tyrosine Kinase Targets in Urothelial Carcinoma

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

Poly(ADP-ribose) polymerase inhibitors in prostate and urothelial cancer

PURPOSE OF REVIEW

The aim of this article is to give an overview of poly(ADP-ribose) polymerase inhibitors (PARPis) trials in prostate cancer and to discuss emerging approaches with potential future clinical implementation in both prostate and urothelial cancer.

RECENT FINDINGS

PARPis are a class of drugs that can be applied for the treatment of homologous recombination repair (HRR)-deficient tumors. Tumors are potentially sensitive to PARPi harbor mutations in genes relevant for DNA damage repair, such as BRCA1/2 or ATM, which are present to a significant degree in metastatic prostate and urothelial cancer patients. Several PARPis have been successfully tested in clinical trials for HRR-deficient metastatic castration-resistant prostate cancer (mCRPC), and olaparib and rucaparib have recently received breakthrough approval in BRCA1/2 mutated mCRPC. Combination treatment of PARPis with androgen-receptor inhibitors or with checkpoint inhibitors and earlier frontline applications are currently being evaluated, and clinical trials enrolling bladder cancer (BCa) patients with HRR deficiency have recently been initiated.

SUMMARY

Approximately 10% of mCRPC patients and 34% of metastatic BCa patients have tumors with HRR deficiency and may benefit from PARPi treatment. Correct identification of these patients as well as determining the most adequate time point for drug administration will be key to successful clinical implementation.

Frontiers in combining immune checkpoint inhibitors for advanced urothelial cancer management

PURPOSE OF REVIEW

This review provides an overview of currently ongoing clinical trials evaluating the combination of immune checkpoint inhibitors (CPI) with other therapies in locally advanced or metastatic urothelial cancer and the rationale for this combination approach. We discuss the preliminary results from early data presented at recent meetings regarding the efficacy and safety of novel combination therapies including a CPI for metastatic urothelial cancer.

RECENT FINDINGS

CPI emerged as novel first-line or second-line treatment options in advanced and metastatic urothelial cancer (mUC). Although the response rates and their sustainability are promising, it is far from a home run. Combination therapies have already shown improved efficacy in several other tumor entities.

SUMMARY

Numerous clinical trials currently investigate combinations of CPI with other CPI, previously established systemic chemotherapy, targeted therapies, vaccines, or accompanied with radiotherapy. Preliminary data shows promising results. These results suggest that targeting pathways of immune response combined with established or novel oncological therapies may lead to a synergistic antitumor effect.

Common germline-somatic variant interactions in advanced urothelial cancer

The prevalence and biological consequences of deleterious germline variants in urothelial cancer (UC) are not fully characterized. We performed whole-exome sequencing (WES) of germline DNA and 157 primary and metastatic tumors from 80 UC patients. We developed a computational framework for identifying putative deleterious germline variants (pDGVs) from WES data. Here, we show that UC patients harbor a high prevalence of pDGVs that truncate tumor suppressor proteins. Deepening somatic loss of heterozygosity in serial tumor samples is observed, suggesting a critical role for these pDGVs in tumor progression. Significant intra-patient heterogeneity in germline-somatic variant interactions results in divergent biological pathway alterations between primary and metastatic tumors. Our results characterize the spectrum of germline variants in UC and highlight their roles in shaping the natural history of the disease. These findings could have broad clinical implications for cancer patients.

Alterations of DNA damage response genes correlate with response and overall survival in anti-PD-1/PD-L1-treated advanced urothelial cancer

DNA damage response (DDR) gene alterations in cancer are associated with a higher tumor mutational burden (TMB) and may impact clinical outcomes of urothelial cancer (UC). Here, we explore the prognostic role of DDR alterations in advanced UC treated with anti-PD-1/PD-L1 agents. The study included 53 patients who had FoundationOne genomic sequencing and received anti-PD-1/PD-L1 therapy. Fisher exact test and trend test were used to assess differences in objective response rate (ORR). Overall survival (OS) was measured from the time of initial UC diagnosis and Cox proportional hazard regression analysis was performed to calculate hazard ratio (HR) and 95% confidence interval (CI). The cohort had a median age of 66 with 64% receiving platinum-based chemotherapy. DDR alterations (including ATM) were associated with a non-significantly higher ORR to PD-1/PD-L1 blockade (41% vs. 21%, p = 0.136). Patients with DDR alterations (excluding ATM) had non-significantly longer OS, likely due to a small sample size (HR = 0.53, 95% CI 0.20-1.38, p = 0.19). ATM alterations were associated with a non-significantly higher ORR (40% vs. 29%, p = 0.6), but also with significantly shorter OS (HR = 5.7, 95% CI 1.65-19.74, p = 0.006). Patients with ≥ 3 DDR alterations (including ATM) had substantially higher TMB (p = 0.01) and higher ORR (80%) with PD-1/PD-L1 blockade versus 24% ORR in patients with <3 DDR alterations. In summary, DDR alterations were associated with non-significantly higher ORR and longer OS for patients with advanced UC receiving anti-PD-1/PD-L1 agents. ATM alterations were associated with shorter OS.

Fibroblast Growth Factor Receptor 3 Mutation as a Prognostic Indicator in Patients with Urothelial Carcinoma: A Systematic Review and Meta-analysis

Background

Fibroblast growth factor receptor 3 (FGFR3) mutations have been implicated in urothelial tumorigenesis. FGFR3 inhibitors are being explored in clinical trials.

Objective

We aimed to study the association between FGFR3 mutations and survival in urothelial carcinoma.

Design, setting, and participants

We performed a systematic literature search of PubMed, Cochrane, Ovid, and Web of Science from January 1985 to October 2018. The search terms were as follows: targeted therapies, FGFR and its subtypes, urothelial, bladder, and cancer. We included case-control or cohort studies of FGFR3 mutations in urothelial carcinoma. We included studies reporting hazard ratios (HRs) and 95% confidence intervals (CIs) for outcomes comparing FGFR3 mutations with FGFR3 wild type. Two reviewers performed article selection.

Outcome measurements and statistical analysis

We assessed heterogeneity among study-specific HRs using I² statistic. We used a random effect model to obtain HR and 95% CI for event-free survival (EFS), composed of recurrence-free and progression-free survival. Statistical tests were two sided.

Results and limitations

Eleven studies (seven retrospective and four prospective) comprising 2162 patients were included. Analysis was performed for two groups. The first group included 1651 patients with non–muscle-invasive (NMI) urothelial carcinomas (886 [53.6%] had FGFR3 mutations). Compared with FGFR3 wild type, FGFR3 mutation did not influence EFS (HR = 0.99, CI = 0.77–1.28, p =  0.96). There was no significant heterogeneity (I² = 25%). The second group included 511 patients with NMI and muscle-invasive (MI) urothelial carcinomas (151 [30%] had FGFR3 mutations). FGFR3 mutation was not prognostic (HR = 1.54, CI = 0.41–5.81, p =  0.52). There was heterogeneity (I² = 91%).

Conclusions

There is no association between FGFR3 mutation and EFS in NMI urothelial carcinoma, and in NMI and MI urothelial carcinoma groups.

Patient summary

Fibroblast growth factor receptor 3 (FGFR3) mutation is not associated with a worse survival outcome in urothelial carcinoma. This is important as FGFR inhibitors are emerging as a new treatment option.

Combination therapy in advanced urothelial cancer: the role of PARP, HER-2 and mTOR inhibitors

INTRODUCTION

Despite significant advances in the treatment of metastatic urothelial carcinoma, including the advent of immune checkpoint inhibitors, this disease is still challenging to treat and associated poor outcomes remain. Genomic characterization of advanced-stage urothelial carcinoma is widening the field of potential treatments due to the identification of novel biologic drivers.

AREAS COVERED

In this review, we explore the role of PARP, HER-2, and mTOR inhibitors in the therapeutic scenario of advanced urothelial carcinoma, as these pathways are frequently altered in urothelial carcinoma. We report ongoing clinical trials involving these agents, either in monotherapy or in combination with other compounds, highlighting the dynamic scenario of metastatic urothelial carcinoma treatment.

EXPERT OPINION

Several challenges need to be faced in the development of new potential therapeutic strategies, such as inter/intratumoral heterogeneity and the lack of validated biomarkers.

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

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

Current Strategies and Novel Therapeutic Approaches for Metastatic Urothelial Carcinoma

Urothelial carcinoma (UC) is a frequent cause of cancer-related deaths worldwide. Metastatic UC has been historically associated with poor prognosis, with a median overall survival of approximately 15 months and a 5-year survival rate of 18%. Although platinum-based chemotherapy remains the mainstay of medical treatment for patients with metastatic UC, chemotherapy clinical trials produced modest benefit with short-lived, disappointing responses. In recent years, the better understanding of the role of immune system in cancer control has led to the development and approval of several immunotherapeutic approaches in UC therapy, where immune checkpoint inhibitors have been revolutionizing the treatment of metastatic UC. Because of a better tumor molecular profiling, FGFR inhibitors, PARP inhibitors, anti-HER2 agents, and antibody drug conjugates targeting Nectin-4 are also emerging as new therapeutic options. Moreover, a wide number of trials is ongoing with the aim to evaluate several other alterations and pathways as new potential targets in metastatic UC. In this review, we will discuss the recent advances and highlight future directions of the medical treatment of UC, with a particular focus on recently published data and ongoing active and recruiting trials.

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 future of bladder cancer therapy: Optimizing the inhibition of the fibroblast growth factor receptor

Therapeutic options for metastatic bladder cancer (BC) have seen minimal evolution over the past 30 years, with platinum-based chemotherapy remaining the mainstay of standard of care for metastatic BC. Recently, five immune checkpoint inhibitors (ICIs) have been approved by the FDA as second-line therapy, and two ICIs are approved as first-line treatment in selected patients. Molecular alterations of muscle-invasive bladder cancer (MIBC) have been reported by The Cancer Genome Atlas. About 15% of patients with MIBC have molecular alterations in the fibroblast growth factor (FGF) axis. Several ongoing trials are testing novel FGF receptor (FGFR) inhibitors in patients with FGFR genomic aberrations. Recently, erdafitinib, a pan-FGFR inhibitor, was approved by the FDA in patients with metastatic BC who have progressed on platinum-based chemotherapy. We reviewed the literature over the last decade and provide a summary of current knowledge of FGF signaling, and the prognosis associated with FGFR mutations in BC. We cover the role of FGFR inhibition with non-selective and selective tyrosine kinase inhibitors as well as novel agents in metastatic BC. Efficacy and safety data including insights from mechanism-based toxicity are reported for selected populations of metastatic BC with FGFR aberrations. Current strategies to managing resistance to anti-FGFR agents is addressed, and the importance of developing reliable biomarkers as the therapeutic landscape moves towards an individualized therapeutic approach.

Precision oncology in urothelial cancer

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