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.

Molecular Predictors of Complete Response Following Neoadjuvant Chemotherapy in Urothelial Carcinoma of the Bladder and Upper Tracts

Urothelial carcinoma of the bladder (UCB) and upper tracts (UTUC) is often regarded as one entity and is managed generally with similar principles. While neoadjuvant chemotherapy (NAC) followed by radical cystectomy (RC) is an established standard of care in UCB, strong evidence for a similar approach is lacking in UTUC. The longest survival is seen in patients with complete response (pT0) on pathological examination of the RC specimen, but impact of delayed RC in nonresponders may be detrimental. The rate of pT0 following NAC in UTUC is considerably lower than that in UCB due to differences in access and instrumentation. Molecular markers have been evaluated to try to predict response to chemotherapy to reduce unnecessary treatment and expedite different treatment for nonresponders. A variety of potential biomarkers have been evaluated to predict response to cisplatin based chemotherapy including DNA repair genes (ATM, RB1, FANCC, ERCC2, BRCA1, and ERCC1), regulators of apoptosis (survivin, Bcl-xL, and emmprin), receptor tyrosine kinases (EGFR and erbB2), genes involved in cellular efflux (MDR1 and CTR1), in addition to molecular subtypes (Basal, luminal, and p53-like). The current state of the literature on the prediction of response to NAC based on the presence of these biomarkers is discussed in this review.

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.

Molecular biomarkers to predict response to neoadjuvant chemotherapy for bladder cancer

Cystectomy is the gold standard for treatment of localized muscle-invasive bladder cancer. However, about 50% of patients develop metastases within 2years after cystectomy and subsequently die for the disease. Neoadjuvant cisplatin-based chemotherapy before cystectomy improves the overall survival in patients with muscle-invasive bladder cancer, and pathological response to neoadjuvant treatment (downstaging to ⩽pT1 at cystectomy) is a strong predictor of better disease-specific survival. Nevertheless, some patients do not benefit from neoadjuvant therapy. The identification of reliable biomarkers that could enable the clinicians to identify patients who will really benefit from neoadjuvant chemotherapy is a major issue. This approach could lead to individualized therapy, in order to optimize the chance of response, avoiding the impact of neoadjuvant treatment on quality of life and the delay of cystectomy in non-responder patients. However, no molecular predictive biomarkers have shown clinical utility. This paper aims to review currently available data about biomarkers predictive of response to neoadjuvant chemotherapy in muscle-invasive bladder cancer.

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

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

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

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

Perioperative and Maintenance Therapy After First-Line Therapy as Paradigms for Drug Discovery in Urothelial Carcinoma

Perioperative chemotherapy provided to increase the chance of cure for localized disease and maintenance therapy for metastatic disease represent 2 distinct aspects of the urothelial cancer disease treatment spectrum. The ability to access both pre- and postchemotherapy tissue in the neoadjuvant setting provides important opportunities for translational research to test novel therapies and identify predictors of response to therapy. The maintenance setting may be more complex, and study design and endpoints need to be determined on the basis of the candidate drugs' mechanisms of action and toxicity.

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.

Accelerated methotrexate, vinblastine, doxorubicin, and cisplatin is safe, effective, and efficient neoadjuvant treatment for muscle-invasive bladder cancer: results of a multicenter phase II study with molecular correlates of response and toxicity

PURPOSE

Neoadjuvant cisplatin-based chemotherapy is standard of care for muscle-invasive bladder cancer (MIBC); however, it is infrequently adopted in practice because of concerns regarding toxicity and delay to cystectomy. We hypothesized that three cycles of neoadjuvant accelerated methotrexate, vinblastine, doxorubicin, and cisplatin (AMVAC) would be safe, shorten the time to surgery, and yield similar pathologic complete response (pT0) rates compared with historical controls.

PATIENTS AND METHODS

Patients with cT2-T4a and N0-N1 MIBC were eligible and received three cycles of AMVAC with pegfilgrastim followed by radical cystectomy with lymph node dissection. The primary end point was pT0 rate. Telomere length (TL) and p53 mutation status were correlated with response and toxicity.

RESULTS

Forty-four patients were accrued; 60% had stage III to IV disease; median age was 64 years. Forty patients were evaluable for response, with 15 (38%; 95% CI, 23% to 53%) showing pT0 at cystectomy, meeting the primary end point of the study. Another six patients (14%) were downstaged to non-muscle invasive disease. Most (82%) experienced only grade 1 to 2 treatment-related toxicities. There were no grade 3 or 4 renal toxicities and no treatment-related deaths. One patient developed metastases and thus did not undergo cystectomy; all others (n = 43) proceeded to cystectomy within 8 weeks after last chemotherapy administration. Median time from start of chemotherapy to cystectomy was 9.7 weeks. TL and p53 mutation did not predict response or toxicity.

CONCLUSION

AMVAC is well tolerated and results in similar pT0 rates with 6 weeks of treatment compared with standard 12-week regimens. Further analysis is ongoing to ascertain whether molecular alterations in tumor samples can predict response to chemotherapy.

Neoadjuvant dose-dense methotrexate, vinblastine, doxorubicin, and cisplatin with pegfilgrastim support in muscle-invasive urothelial cancer: pathologic, radiologic, and biomarker correlates

PURPOSE

In advanced urothelial cancer, treatment with dose-dense methotrexate, vinblastine, doxorubicin, and cisplatin (ddMVAC) results in a high response rate, less toxicity, and few dosing delays. We explored the efficacy and safety of neoadjuvant ddMVAC with pegfilgrastim support in muscle-invasive urothelial cancer (MIUC).

PATIENTS AND METHODS

Patients with cT2-cT4, N0-1, M0 MIUC were enrolled. Four cycles of ddMVAC were administered, followed by radical cystectomy. The primary end point was pathologic response (PaR) defined by pathologic downstaging to ≤ pT1N0M0. The study used Simon's optimal two-stage design to evaluate null and alternative hypotheses of PaR rate of 35% versus 55%. Secondary end points included toxicity, disease-free survival (DFS), radiologic response (RaR), and biomarker correlates, including ERCC1.

RESULTS

Between December 2008 and April 2012, 39 patients (cT2N0, 33%; cT3N0, 18%; cT4N0, 3%; cT2-4N1, 43%; unspecified, 3%) were enrolled. Median follow-up was 2 years. Overall, 49% (80% CI, 38 to 61) achieved PaR of ≤ pT1N0M0, and we concluded this regimen was effective. High-grade (grade ≥ 3) toxicities were observed in 10% of patients, with no neutropenic fevers or treatment-related death. One-year DFS was 89% versus 67% for patients who achieved PaR compared with those who did not (hazard ratio [HR], 2.6; 95% CI, 0.8 to 8.1; P = .08) and 86% versus 62% for patients who achieved RaR compared with those who did not (HR, 4.1; 95% CI, 1.3 to 12.5; P = .009). We found no association between serum tumor markers or ERCC1 expression with response or survival.

CONCLUSION

In patients with MIUC, neoadjuvant ddMVAC was well tolerated and resulted in significant pathologic and radiologic downstaging.

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.

Antiangiogenic Agents, Chemotherapy, and the Treatment of Metastatic Transitional Cell Carcinoma

A 69-year-old man with a 100 pack-year history of smoking developed gross hematuria. His medical history included hypertension, a silent myocardial infarction, and a cerebrovascular accident complicated by seizures. Cystoscopy and biopsy showed a 4-cm mass at the right ureteral orifice positive for a high-grade papillary transitional cell carcinoma (TCC) with muscularis propria invasion (Fig 1). The computed tomography (CT)/positron emission tomography (PET) scan of the chest, abdomen, and pelvis showed hydronephrosis and hydroureter with marked cortical thinning and multiple bilateral PET-avid pulmonary nodules, with the largest in the left upper lung measuring 3.0 × 2.5 cm (Figs 2A, 3A), biopsy of which showed invasive high-grade urothelial carcinoma. The patient consented to join a clinical trial for metastatic TCC (USON [US Oncology Network study] 06040) involving treatment with gemcitabine, cisplatin, and sunitinib (GCS) 37.5 mg per day.1Four days later, he experienced a 10-day hospitalization for acute pancreatitis and neutropenia. Sunitinib was discontinued, and he completed four additional cycles of GC. CT/PET showed that the right ureteral mass and all lung nodules had regressed or disappeared (Figs 2B, 3B). The largest remaining lung nodule at 1.4 cm showed no metabolic activity. He underwent a radical cystoprostatectomy and right nephroureterectomy, disclosing residual high-grade urothelial carcinoma infiltrating the full thickness of the ureteral wall. There was carcinoma in situ of the bladder, and 42 nodes were negative for cancer. The surgery was followed by a small, uncomplicated myocardial infarction. A scheduled left thoracotomy to remove the remaining nodule was cancelled. No additional chemotherapy was administered, and the patient remains free of recurrence 2 years from initiation of chemotherapy. The 1.4-cm nodule has calcified and remains stable and metabolically inactive. He has no sequelae of chemotherapy or surgery, with a creatinine level of 1.35 mg/dL.

Oncologic outcomes obtained after neoadjuvant and adjuvant chemotherapy for the treatment of urothelial carcinomas of the upper urinary tract: a review

INTRODUCTION

Nephroureterectomy with excision of a bladder cuff is the gold standard in the treatment of upper urinary tract carcinomas (UTUC). But especially for patients suffering from advanced tumor stages, life expectancy has not improved over the years with local recurrence or distant metastases being the main reasons for treatment failure. Chemotherapy in an adjuvant or neoadjuvant setting seems therefore to be a promising approach.

METHODS

The literature of the last 20 years was searched using Medline. Articles were chosen by using the given abstracts. Only articles written in English and not older than 20 years were considered.

RESULTS

Most information concerning chemotherapy of urothelial carcinomas is gained from studies comprising patients suffering from lower urinary tract carcinomas. The combination of methotrexate, adriamycin, vinblastine and cisplatin as well as the combination of gemcitabine and cisplatin are the most used chemotherapy regimens in advanced UCC and have shown beneficial results. The summarized data of studies for UTUC contained no level one information. Down staging effects as well as prolongation of survival have been shown for some patients treated with neoadjuvant chemotherapy, but because of the small study groups and the retrospective design, no definite conclusions can be drawn from these results. In addition, there exists an uncertainty for preoperative staging. Results for adjuvant chemotherapy are lacking.

CONCLUSION

No definite recommendations for peri-operative chemotherapy in UTUC can be derived from the current literature. Current therapy is largely based on extrapolation from the bladder cancer literature. Prospective studies dedicated to UTUC are needed.

Novel molecular targets for the therapy of urothelial carcinoma

INTRODUCTION

First-line platinum-based combinations are active in locally advanced and metastatic urothelial carcinoma; however, long-term outcomes including disease-specific and overall survival remain suboptimal. In addition, approximately 40 - 50% of patients with advanced urothelial carcinoma have coexisting medical issues that preclude the use of cisplatin-based therapy. Improvements in our understanding of the molecular mechanisms of urothelial tumorigenesis have led to first-generation clinical trials evaluating novel agents targeting molecular pathways. These are particularly relevant in regard to subpopulations. Novel trial designs warrant consideration to accelerate accrual.

AREAS COVERED

In this review, novel molecular targets for the therapy of urothelial carcinoma, as well as recently completed and ongoing clinical trials utilizing novel targeted agents, are discussed. A Medline search with key words, abstracts reported at national conferences on urothelial carcinoma and NCI clinical trial identifiers was used for this review.

EXPERT OPINION

Improved understanding of molecular biology has identified a number of new molecular targets, but there is a seeming absence of one dominant molecular driver for urothelial cancer. An adaptive and biomarker-derived strategy may be warranted. Clinical trials utilizing targeted agents are ongoing and results are awaited.