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

INTRODUCTION

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

Cabozantinib in genitourinary malignancies

Cabozantinib inhibits a variety of cellular receptors including VEGFR1-3, MET, AXL, RET, FLT3 and KIT. These signaling pathways have been shown to be important in genitourinary malignancies. Along its clinical development, it has shown most activity in advanced renal cell carcinoma; the METEOR study compared cabozantinib to everolimus and showed clinically and statistically significant improvements in both progression-free survival and overall survival. Herein, we review the development of cabozantinib in the genitourinary malignancies of renal cell carcinoma, prostate adenocarcinoma and urothelial carcinoma.

Preliminary evaluation of urinary soluble Met as a biomarker for urothelial carcinoma of the bladder

BACKGROUND

Among genitourinary malignancies, bladder cancer (BCa) ranks second in both prevalence and cause of death. Biomarkers of BCa for diagnosis, prognosis and disease surveillance could potentially help prevent progression, improve survival rates and reduce health care costs. Among several oncogenic signaling pathways implicated in BCa progression is that of hepatocyte growth factor (HGF) and its cell surface receptor, Met, now targeted by 25 experimental anti-cancer agents in human clinical trials. The involvement of this pathway in several cancers is likely to preclude the use of urinary soluble Met (sMet), which has been correlated with malignancy, for initial BCa screening. However, its potential utility as an aid to disease surveillance and to identify patients likely to benefit from HGF/Met-targeted therapies provide the rationale for this preliminary retrospective study comparing sMet levels between benign conditions and primary BCa, and in BCa cases, between different disease stages.

METHODS

Normally voided urine samples were collected from patients with BCa (Total: 183; pTa: 55, pTis: 62, pT1: 24, pT2: 42) and without BCa (Total: 83) on tissue-procurement protocols at three institutions and sMet was measured and normalized to urinary creatinine. Normalized sMet values grouped by pathologic stage were compared using non-parametric tests for correlation and significant difference. ROC analyses were used to derive classification models for patients with or without BCa and patients with or without muscle-invasive BCa (MIBCa or NMIBCa).

RESULTS

Urinary sMet levels accurately distinguished patients with BCa from those without (p<0.0001, area under the curve (AUC): 0.7008) with limited sensitivity (61%) and moderate specificity (76%), and patients with MIBCa (n=42) from those with NMIBCa (n=141; p<0.0001, AUC: 0.8002) with moderate sensitivity and specificity (76% and 77%, respectively) and low false negative rate (8%).

CONCLUSIONS

Urinary sMet levels distinguish patients with BCa from those without, and patients with or without MIBCa, suggesting the potential utility of urinary sMet as a BCa biomarker for surveillance following initial treatment. Further studies are warranted to determine its potential value for prognosis in advanced disease, predicting treatment response, or identifying patients likely to benefit from Met-targeted therapies.

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.