Francesca Vignani

Addition of Docetaxel to Androgen Deprivation Therapy for Patients with Hormone-sensitive Metastatic Prostate Cancer: A Systematic Review and Meta-analysis

CONTEXT Several randomized clinical trials (RCTs) have recently tested the early addition of docetaxel to androgen deprivation therapy (ADT) in hormone-sensitive metastatic prostate cancer (PCa). OBJECTIVE To perform a systematic review and meta-analysis of RCTs evaluating the combination of docetaxel and ADT in hormone-sensitive metastatic PCa. The primary end point was overall survival (OS). Secondary end point was progression-free survival. Exploratory subgroup analysis according to high-volume versus low-volume disease was performed. EVIDENCE ACQUISITION A systematic review of PubMed/Medline, Embase, and the proceedings of major international meetings was performed in June 2015 and updated in August 2015. Three trials were selected for inclusion. EVIDENCE SYNTHESIS Overall, 2951 patients were included in the three trials. Two trials enrolled only metastatic patients; in the third trial, 61% were metastatic. A total of 2262 patients (951 docetaxel and ADT; 1311 ADT alone) were metastatic. Most patients had a good performance status. In metastatic patients, the addition of docetaxel was associated with improved OS (hazard ratio [HR]: 0.73; 95% confidence interval [CI], 0.60-0.90; p=0.002), with nonsignificant heterogeneity among the three trials. Considering the whole study population (2951 patients), the addition of docetaxel was associated with a similar OS improvement (HR: 0.74; 95% CI, 0.61-0.91; p=0.003). Although with limited statistical power, no significant interaction was demonstrated between the addition of docetaxel and the high or low volume of disease (p=0.5). The addition of docetaxel was associated with improvement in progression-free survival (metastatic patients: HR: 0.63; 95% CI, 0.57-0.70; p<0.001). CONCLUSIONS This meta-analysis shows a significant OS benefit from concomitant administration of docetaxel and ADT in patients with metastatic hormone-sensitive PCa. PATIENT SUMMARY We synthesized the evidence available about the early administration of docetaxel in patients starting hormonal treatment for metastatic prostate cancer. Based on the results of this meta-analysis, we believe the combination of chemotherapy and hormonal treatment should be considered in fit patients.

Understanding and overcoming the mechanisms of primary and acquired resistance to abiraterone and enzalutamide in castration resistant prostate cancer

In recent years, in castration resistant prostate cancer (CRPC), several new drugs have been approved that prolong overall survival, including enzalutamide and abiraterone, two new-generation hormonal therapies. Despite the demonstrated benefit of these agents, not all patients with CRPC are responsive to treatment, the gain in median progression-free survival with these therapies compared to standard of care is, rather disappointingly, still less than six months and the appearance of acquired resistance is almost universal. Approximately one third of patients treated with abiraterone and 25% of those treated with enzalutamide show primary resistance to these agents. Even if the mechanisms of resistance to these agents are not fully defined, many hypotheses are emerging, including systemic and intratumoral androgen biosynthesis up-regulation, androgen receptor (AR) gene mutations and amplifications, alteration of pathways involved in cross-talk with AR signaling, glucocorticoid receptor overexpression, neuroendocrine differentiation, immune system deregulation and others. The aim of this paper is to review currently available data about mechanisms of resistance to abiraterone and enzalutamide, and to discuss how these mechanisms could be potentially overcome through novel therapeutic agents.

Skeletal metastases and impact of anticancer and bone-targeted agents in patients with castration-resistant prostate cancer

Incidence of bone metastases is very high in advanced prostate cancer patients. Bone metastases likely have a significant impact on functional status and quality of life, not only related to pain, but also to the relevant risk of skeletal-related events. A better understanding of mechanisms associated with bone metastatic disease secondary to prostate cancer and more specifically to the cross-talk between tumor cells and bone microenvironment in metastatic progression represented the background for the development of new effective bone-targeted therapies. Furthermore, a better knowledge of biological mechanisms driving disease progression led to significant advances in the treatment of castration-resistant prostate cancer, with the development and approval of new effective drugs. Aim of this review is to outline the physiopathology of bone metastases in prostate cancer and summarize the main results of clinical trials conducted with different drugs to control morbidity induced by skeletal metastases and bone disease progression. For each agent, therapeutic effect on bone metastases has been measured in terms of pain control and/or incidence of skeletal-related events, usually defined as a composite endpoint, including the need for local treatment (radiation therapy or surgery), spinal cord compression, pathological bone fractures. In details, data obtained with chemotherapy (mitoxantrone, docetaxel, cabazitaxel), new generation hormonal agents (abiraterone, enzalutamide), radium-223, bone-targeted agents (zoledronic acid, denosumab) and with several experimental agents (cabozantinib, dasatinib, anti-endothelin and other agents) in patients with castration-resistant prostate cancer are reviewed.

Strategies for managing ACTH dependent mineralocorticoid excess induced by abiraterone

BACKGROUND Abiraterone strongly inhibits androgen synthesis but may lead to an increase in mineralocorticoid hormones that may impair its long term tolerability in patients with prostate cancer. How to implement available therapies in the management and prevention of these potential side effects is a matter of current clinical research. METHODS The acute and long term consequences of mineralocorticoid excess and the effects of available treatments have been reviewed. Prospective studies in which abiraterone was employed were identified to assess the frequency and severity of the mineralocorticoid excess syndrome and the efficacy of ameliorating therapeutic approaches. RESULTS Glucocorticoids to inhibit the ACTH increase that drives mineralocorticoid synthesis and mineralocorticoid receptor (MR) antagonists can be used in the management of the abiraterone-induced mineralocorticoid excess syndrome. Phase I and II trials of abiraterone without additional therapies revealed that mineralocorticoid excess symptoms occur in the majority of patients. Eplerenone, a specific MR antagonist, seems to be effective but it does not control the mineralocorticoid excess. Glucorticoid supplementation to control ACTH drive is therefore needed. In several randomized trials the addition of prednisone (10mg daily) to abiraterone was not able to prevent mineralocorticoid excess syndrome in many cases and thus cannot be considered the gold standard. CONCLUSION At present, the best conceivable treatment for managing the abiraterone-induced mineralocorticoid excess consists of the administration of glucocorticoid replacement at the lowest effective dose ± MR antagonists and salt deprivation. The drug doses should be modulated by monitoring blood pressure, fluid retention and potassium levels during therapy.

Prognostic role of neuroendocrine differentiation in prostate cancer, putting together the pieces of the puzzle

Neuroendocrine (NE) differentiation is a common feature in prostate cancer (PC). The clinical significance of this phenomenon is controversial; however preclinical and clinical data are in favor of an association with poor prognosis and early onset of a castrate resistant status. NE PC cells do not proliferate, but they can stimulate the proliferation of the exocrine component through the production of paracrine growth factors. The same paracrine signals may favor the outgrowth of castrate adapted tumors through androgen receptor dependent or independent mechanisms. Noteworthy, NE differentiation in PC is not a stable phenotype, being stimulated by several agents including androgen deprivation therapy, radiation therapy, and chemotherapy. The proportion of NE positive PC, therefore, is destined to increase during the natural history of the disease. This may complicate the assessment of the prognostic significance of this phenomenon. The majority of clinical studies have shown a significant correlation between NE differentiation and disease prognosis, confirming the preclinical rationale. In conclusion the NE phenotype is a prognostic parameter in PC. Whether this phenomenon is a pure prognostic factor or whether it can influence the prognosis by favoring the onset of a castrate resistance status is a matter of future research.

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.

Metastatic castration-resistant prostate cancer: time for innovation

Androgen deprivation is the mainstay of advanced prostate cancer treatment. Despite initial responses, almost all patients progress to castration-resistant prostate cancer (CRPC). The understanding of the biology of CRPC and the evidence that CRPC still remains driven by androgen receptor signaling led to the discovery of new therapeutic targets. In the last few years, large Phase III trials showed improvements in survival and outcomes and led to the approval of a CYP17 inhibitor (abiraterone), an androgen receptor antagonist (enzalutamide), the taxane cabazitaxel, an α-emitter (radium-223), the bone resorption-targeting drug denosumab and an immunotherapy (sipuleucel-T). This article describes the molecular mechanisms underlying castration resistance, discusses recent and ongoing trials and offers some insights into identifying the best sequence of new drugs.

Immunotherapy for Patients with Advanced Urothelial Cancer: Current Evidence and Future Perspectives

In recent years, immunotherapy has produced encouraging results in a rapidly increasing number of solid tumors. The responsiveness of bladder cancer to immunotherapy was first established in nonmuscle invasive disease in 1976 with intravesical instillations of bacillus Calmette-Guérin (BCG). Very recently immune checkpoint inhibitors demonstrated good activity and significant efficacy in metastatic disease. In particular the best results were obtained with programmed death-ligand-1 (PD-L1) and programmed death-1 (PD-1) inhibitors, but many other immune checkpoint inhibitors, including anti-cytotoxic T-lymphocyte-associated protein-4 (CTLA-4) antibodies, are currently under investigation in several trials. Simultaneously other therapeutic strategies which recruit an adaptive immune response against tumoral antigens or employ externally manipulated tumor infiltrating lymphocytes might change the natural history of bladder cancer in the near future. This review describes the rationale for the use of immunotherapy in bladder cancer and discusses recent and ongoing clinical trials with checkpoint inhibitors and other novel immunotherapy agents.

Antiandrogen withdrawal syndrome (AAWS) in the treatment of patients with prostate cancer

Antiandrogen withdrawal syndrome is an unpredictable event diagnosed in patients with hormone-sensitive prostate cancer treated with combined androgen blockade therapy. It is defined by prostate-specific antigen value reduction, occasionally associated with a radiological response, that occurs 4-6 weeks after first-generation antiandrogen therapy discontinuation. New-generation hormonal therapies, such as enzalutamide and abiraterone acetate, improved the overall survival in patients with metastatic castration-resistant prostate cancer, and recent trials have also shown the efficacy of abiraterone in hormone-sensitive disease. In the last few years, several case reports and retrospective studies suggested that the withdrawal syndrome may also occur with these new drugs. This review summarizes literature data and hypothesis about the biological rationale underlying the syndrome and its potential clinical relevance, focusing mainly on new-generation hormonal therapies. Several in vitro studies suggest that androgen receptor gain-of-function mutations are involved in this syndrome, shifting the antiandrogen activity from antagonist to agonist. Several different drug-specific point mutations have been reported. The association of the withdrawal syndrome for enzalutamide and abiraterone needs confirmation by additional investigations. However, new-generation hormonal therapies being increasingly used in all stages of disease, more patients may experience the syndrome when stopping the treatment at the time of disease progression, although the clinical relevance of this phenomenon in the management of metastatic castration-resistant prostate cancer remains to be defined.

Prognostic impact of pretreatment neutrophil-to-lymphocyte ratio in castration-resistant prostate cancer patients treated with first-line docetaxel

Abstract Background: The neutrophil-to-lymphocyte ratio (NLR), a measure of systemic inflammatory response, has been associated with poor outcome in several solid tumors, including prostate cancer. We retrospectively investigated the prognostic role of pretreatment NLR in metastatic castration-resistant prostate cancer (mCRPC) patients treated with first-line docetaxel. Methods: All CRPC patients treated with first-line docetaxel at two Italian institutions, with available data about baseline neutrophil and lymphocyte values, were included in this retrospective analysis. Patients were divided in two groups according to NLR ratio (low NLR: ≤3; high NLR: >3). Outcome measures were progression-free (PFS) and overall survival (OS), measured from the start of docetaxel treatment. Univariate and multivariate analysis (adjusting for baseline prostate-specific antigen, alkaline phosphatase, lactate dehydrogenase, hemoglobin, albumin, performance status, use of opioids and presence of visceral disease) were performed. Results: One hundred and seventy-nine patients treated between 2004 and 2016 were analyzed and 110 had information about pretreatment NLR. Forty-six patients (42%) had low NLR and 64 (58%) had high NLR. Median PFS was 8.8 months in patients with low NLR versus 7.3 months in those with high NLR [hazard ratio (HR) 1.12, 95% confidence interval (CI) 0.75–1.69, p = .58]. Median OS was 34.9 months in patients with low NLR versus 20.2 months in those with high NLR (HR 1.85, 95% CI 1.07–3.19, p = .02). At multivariate analysis, NLR confirmed an independent impact on OS (HR 3.16, 95% CI 1.50–6.65, p = .002). Conclusion: In this retrospective series, metastatic CRPC patients who started first-line docetaxel with a low pretreatment NLR had a significantly better survival. In addition to known prognostic factors, NLR can be useful to improve prognostic evaluation of patients in this setting.