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.

Neoadjuvant sorafenib, gemcitabine, and cisplatin administration preceding cystectomy in patients with muscle-invasive urothelial bladder carcinoma: An open-label, single-arm, single-center, phase 2 study

BACKGROUND

Outcomes of neoadjuvant chemotherapy in patients with muscle-invasive urothelial bladder carcinoma (MIUBC) should be improved. Sorafenib was combined with gemcitabine and cisplatin chemotherapy (SGC) in an open-label, single-arm, phase 2 trial (NCT01222676).

PATIENTS AND METHODS

After transurethral resection of the bladder, T2-T4a N0 patients received four cycles of SGC followed by cystectomy. Sorafenib 400mg q12h daily, continuously, was added to standard GC chemotherapy. In a Simon's 2-stage design, the primary endpoint was the pathologic complete response (pT0), assuming H0: ≤0.20 and H1: ≥0.40, with a type I and type II error of 5% and 10%, respectively.

RESULTS

From April 2011 to June 2016, 46 patients were enrolled. Pathologic T0 response was obtained in 20 patients (43.5%, 95% CI: 28.9-58.9); pT ≤ 1 in 25 (54.3%, 95% CI: 39.0-69.1). After a median follow-up of 35 months, the median progression-free survival was not reached (NR, interquartile range: 23.6-NR), nor was median overall survival (interquartile range: 30.3-NR). Hematologic and extrahematologic grade 3 to 4 adverse events occurred in 45.6% and 26.1% of patients, respectively. In 29 samples from responders (pT ≤ 1) and nonresponders, different distribution of missense mutations involved DNA-repair genes, RAS-RAF pathway genes, chromatin-remodeling genes, and HER-family genes. ERCC1 immunohistochemical expression was associated with pT ≤ 1 response (P = 0.047). The absence of a comparator arm prevented us to quantify sorafenib contribution.

CONCLUSIONS

SGC combination was active in MIUBC, and the identified molecular features included alterations that may help personalize treatment in MIUBC with new more potent targeted agents, combined with chemotherapy.

Contemporary update on neoadjuvant therapy for bladder cancer

Administration of neoadjuvant chemotherapy preceding radical cystectomy in patients with bladder cancer remains a matter of debate. Results of prospective, randomized studies have demonstrated an overall absolute survival benefit of 5% at 5 years, provided cisplatin-based combination regimens are used. Owing to the perception of a modest survival benefit, the medical community has been slow to adopt the use of neoadjuvant chemotherapy. Other reasons for the underuse of neoadjuvant chemotherapy range from patient ineligibility to fear of delaying potentially curative surgery in nonresponders. Instead, several institutions have adopted an individualized, risk-adapted approach, in which the decision to administer chemotherapy is based on clinical stage and patient comorbidity profile. The development of new cytotoxic and targeted therapies, in particular immune checkpoint inhibitors, warrants well-designed prospective studies to test their efficacy alone or in combination in the neoadjuvant setting. Moving forward, genomic characterization of muscle-invasive bladder cancer could offer information that aids clinicians in selecting the appropriate chemotherapy regimen. Following neoadjuvant therapy, every effort should be made to ensure optimal surgery, as surgical margins and the number of removed lymph nodes are prognostic factors; thus, radical cystectomy and a meticulous extended pelvic lymph node dissection should be performed by expert surgeons.

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.

Role of neoadjuvant chemotherapy in muscle-invasive bladder cancer: Clinical and cost effectiveness

Background:

Bladder cancer is one of the most common cancers in the Western world, with associated significant mortality. Once proven to be muscle invasive, radical therapy is required.

Objective:

We reviewed the literature associated with clinical effectiveness of neoadjuvant chemotherapy (NAC) for muscle-invasive bladder cancer.

Methods:

We conducted a systematic literature review of papers related to the search terms neoadjuvant chemotherapy, muscle invasive bladder cancer and clinical effectiveness; from 1984 through April 2014. We used the search terms of (neoadjuvant chemotherapy) AND (muscle invasive bladder cancer). We included primary research, but only included secondary research if it was a systematic review or meta-analyses. Papers outside this category were not included.

Results:

From the literature review, we found that the benefits of neoadjuvant chemotherapy for muscle-invasive bladder cancer are wide-ranging. This includes a greatly improved response rate, including complete response and improved survival rate. Potential disadvantages of NAC include less accurate staging, delays in curative surgery (risk is greater, if delay > 12 weeks) in non-responders and the well-known fact that non-responders will fare worse, later on.

Conclusions:

In conclusion, NAC followed by radical therapy is the gold standard for muscle-invasive bladder tumours, for patients whom are sufficiently fit; however, there are many unanswered questions. As yet, this intervention has not been examined by the National Institute for Health and Care Excellence.

Current and recent clinical trials for perioperative systemic therapy for muscle invasive bladder cancer: a systematic review

BACKGROUND

Although Muscle Invasive Bladder Cancer (MIBC) is increasing in incidence, treatment has largely remained limited to radical cystectomy with or without cisplatin-based neoadjuvant and/or adjuvant chemotherapy. We reviewed the current and recent clinical trials evaluating perioperative chemotherapy, targeted therapy, and novel therapeutic regimens for MIBC patients undergoing radical cystectomy.

METHODS

An overview of perioperative MIBC management was conducted initially using MEDLINE. The Clinical Trials Registry and MEDLINE were further searched specifically for perioperative MIBC chemotherapy, targeted therapy, and other novel therapeutic approaches. Trials involving non-perioperative management, operative management other than radical cystectomy, multiple tumors, or purely superficial or metastatic disease were excluded from selection. These criteria were not specifically fulfilled for mTOR inhibitor and immune therapy trials. Only phase III chemotherapy and phase II targeted therapy trials found in the Clinical Trials Registry were selected. MEDLINE searches of specific treatments were limited to January 2009 to January 2014 whereas the Clinical Trials Registry search had no timeline. Systematic MEDLINE searches had no phase restrictions. Trials known by the authors to fulfill search criteria but were not found via searches were also selected.

RESULTS

Twenty-five trials were selected from the Clinical Trials Registry including 7 phase III chemotherapy trials, 11 Phase II targeted therapy trials, 3 immune therapy trials, 1 mammalian target of rapamycin (mTOR) inhibitor trial, and 3 gene and vaccine therapy trials. Nine trials have been completed and 5 have been terminated early or withdrawn. Nine trials have data available when individually searched using MEDLINE and/or Google. Systematic searches of MEDLINE separately found 12 trials in the past 5 years. Two phase III chemotherapy trials were selected based on knowledge by the authors. No phase III trials of targeted therapy have been registered or published.

CONCLUSIONS

New trials are currently being conducted that may revolutionize MIBC treatment preceding or following cystectomy. Head-to-head phase III trials of perioperative chemotherapy and further phase II and phase III trials of targeted therapy and other therapeutic approaches are necessary before the current cisplatin-based perioperative chemotherapy paradigm is altered.