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.

Targeted agents in second-line bladder cancer therapy

The treatment of metastasized urothelial cancer has been evolving in recent years. In particular, in the second-line setting after the failure of platinum-containing therapy, options are few and besides vinflunine, the recently approved standard in Europe, well-designed highly selective clinical trials may be possible alternatives for patients in this palliative situation. However, targeted therapy approaches have not achieved the same results in urothelial cancer as for instance in renal cell carcinoma. Many of the new targeted drugs have been investigated as single agents in phase II clinical trials without convincing oncologic outcome. This review aims to highlight the most relevant clinical studies examining targeted agents in the second-line setting of metastasized transitional carcinoma of the urothelium.

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.

Emerging therapies for urothelial cancer

Urothelial carcinoma is one of the leading causes of death in Europe and the United States. Despite its chemosensitivity, median overall survival for advanced disease is still nearly 1 year. Most second-line chemotherapeutic agents tested have been disappointing. Thus, new treatment strategies are clearly needed. This review focuses on emerging therapies in urothelial carcinoma. Results from recent clinical trials, investigating the activity of new generation cytostatic agents, as well as results from studies assessing the toxicity and efficacy of novel targeted therapies, are discussed. In this setting, anti-epidermal growth factor receptor, angiogenesis, and phosphatidylinositol 3-kinase/mammalian target of rapamycin inhibitors account for the majority of phase I and II trials.