A randomized, double-blind, placebo-controlled phase II study of vandetanib plus docetaxel/prednisolone in patients with hormone-refractory prostate cancer

Cancer-associated fibroblasts and prostate cancer stem cells: crosstalk mechanisms and implications for disease progression

The functional heterogeneity and ecological niche of prostate cancer stem cells (PCSCs), which are major drivers of prostate cancer development and treatment resistance, have attracted considerable research attention. Cancer-associated fibroblasts (CAFs), which are crucial components of the tumor microenvironment (TME), substantially affect PCSC stemness. Additionally, CAFs promote PCSC growth and survival by releasing signaling molecules and modifying the surrounding environment. Conversely, PCSCs may affect the characteristics and behavior of CAFs by producing various molecules. This crosstalk mechanism is potentially crucial for prostate cancer progression and the development of treatment resistance. Using organoids to model the TME enables an in-depth study of CAF-PCSC interactions, providing a valuable preclinical tool to accurately evaluate potential target genes and design novel treatment strategies for prostate cancer. The objective of this review is to discuss the current research on the multilevel and multitarget regulatory mechanisms underlying CAF-PCSC interactions and crosstalk, aiming to inform therapeutic approaches that address challenges in prostate cancer treatment.

The novel transcriptomic signature of angiogenesis predicts clinical outcome, tumor microenvironment and treatment response for prostate adenocarcinoma

Angiogenesis plays the critical roles in promoting tumor progression, aggressiveness, and metastasis. Although few studies have revealed some angiogenesis-related genes (ARGs) could serve as prognosis-related biomarkers for the prostate cancer (PCa), the integrated role of ARGs has not been systematically studied. The RNA-sequencing data and clinical information of prostate adenocarcinoma (PRAD) were downloaded from The Cancer Genome Atlas (TCGA) as discovery dataset. Twenty-three ARGs in total were identified to be correlated with prognosis of PRAD by the univariate Cox regression analysis, and a 19-ARG signature was further developed with significant correlation with the disease-free survival (DFS) of PRAD by the least absolute shrinkage and selection operator (LASSO) Cox regression with tenfold cross-validation. The signature stratified PRAD patients into high- and low-ARGs signature score groups, and those with high ARGs signature score were associated with significantly poorer outcomes (median DFS: 62.71 months vs unreached, p < 0.0001). The predicting ability of ARGs signature was subsequently validated in two independent cohorts of GSE40272 & PRAD_MSKCC. Notably, the 19-ARG signature outperformed the typical clinical features or each involved ARG in predicting the DFS of PRAD. Furthermore, a prognostic nomogram was constructed with three independent prognostic factors, including the ARGs signature, T stage and Gleason score. The predicted results from the nomogram (C-index = 0.799, 95%CI = 0.744-0.854) matched well with the observed outcomes, which was verified by the calibration curves. The values of area under receiver operating characteristic curve (AUC) for DFS at 1-, 3-, 5-year for the nomogram were 0.82, 0.83, and 0.83, respectively, indicating the performance of nomogram model is of reasonably high accuracy and robustness. Moreover, functional enrichment analysis demonstrated the potential targets of E2F targets, G2M checkpoint pathways, and cell cycle pathways to suppress the PRAD progression. Of note, the high-risk PRAD patients were more sensitive to immune therapies, but Treg might hinder benefits from immunotherapies. Additionally, this established tool also could predict response to neoadjuvant androgen deprivation therapy (ADT) and some chemotherapy drugs, such as cisplatin, paclitaxel, and docetaxel, etc. The novel ARGs signature, with prognostic significance, can further promote the application of targeted therapies in different stratifications of PCa patients.

Angiogenesis and Anti-Angiogenic Treatment in Prostate Cancer: Mechanisms of Action and Molecular Targets

Prostate cancer (PC) is the most common cancer in men and the second leading cause of cancer-related death worldwide. Many therapeutic advances over the last two decades have led to an improvement in the survival of patients with metastatic PC, yet the majority of these patients still succumb to their disease. Antiagiogenic therapies have shown substantial benefits for many types of cancer but only a marginal benefit for PC. Ongoing clinical trials investigate antiangiogenic monotherapies or combination therapies. Despite the important role of angiogenesis in PC, clinical trials in refractory castration-resistant PC (CRPC) have demonstrated increased toxicity with no clinical benefit. A better understanding of the mechanism of angiogenesis may help to understand the failure of trials, possibly leading to the development of new targeted anti-angiogenic therapies in PC. These could include the identification of specific subsets of patients who might benefit from these therapeutic strategies. This paper provides a comprehensive review of the pathways involved in the angiogenesis, the chemotherapeutic agents with antiangiogenic activity, the available studies on anti-angiogenic agents and the potential mechanisms of resistance.

Signaling Pathways That Control Apoptosis in Prostate Cancer

Prostate cancer is the second most common malignancy and the fifth leading cancer-caused death in men worldwide. Therapies that target the androgen receptor axis induce apoptosis in normal prostates and provide temporary relief for advanced disease, yet prostate cancer that acquired androgen independence (so called castration-resistant prostate cancer, CRPC) invariably progresses to lethal disease. There is accumulating evidence that androgen receptor signaling do not regulate apoptosis and proliferation in prostate epithelial cells in a cell-autonomous fashion. Instead, androgen receptor activation in stroma compartments induces expression of unknown paracrine factors that maintain homeostasis of the prostate epithelium. This paradigm calls for new studies to identify paracrine factors and signaling pathways that control the survival of normal epithelial cells and to determine which apoptosis regulatory molecules are targeted by these pathways. This review summarizes the recent progress in understanding the mechanism of apoptosis induced by androgen ablation in prostate epithelial cells with emphasis on the roles of BCL-2 family proteins and "druggable" signaling pathways that control these proteins. A summary of the clinical trials of inhibitors of anti-apoptotic signaling pathways is also provided. Evidently, better knowledge of the apoptosis regulation in prostate epithelial cells is needed to understand mechanisms of androgen-independence and implement life-extending therapies for CRPC.

Pseudomonas Exotoxin A Based Toxins Targeting Epidermal Growth Factor Receptor for the Treatment of Prostate Cancer

The epidermal growth factor receptor (EGFR) was found to be a valuable target on prostate cancer (PCa) cells. However, EGFR inhibitors mostly failed in clinical studies with patients suffering from PCa. We therefore tested the targeted toxins EGF-PE40 and EGF-PE24mut consisting of the natural ligand EGF as binding domain and PE40, the natural toxin domain of Pseudomonas Exotoxin A, or PE24mut, the de-immunized variant thereof, as toxin domains. Both targeted toxins were expressed in the periplasm of E.coli and evoked an inhibition of protein biosynthesis in EGFR-expressing PCa cells. Concentration- and time-dependent killing of PCa cells was found with IC50 values after 48 and 72 h in the low nanomolar or picomolar range based on the induction of apoptosis. EGF-PE24mut was found to be about 11- to 120-fold less toxic than EGF-PE40. Both targeted toxins were more than 600 to 140,000-fold more cytotoxic than the EGFR inhibitor erlotinib. Due to their high and specific cytotoxicity, the EGF-based targeted toxins EGF-PE40 and EGF-PE24mut represent promising candidates for the future treatment of PCa.

Angiogenesis Inhibition in Prostate Cancer: An Update

Prostate cancer (PCa), like all other solid tumors, relies on angiogenesis for growth, progression, and the dissemination of tumor cells to other parts of the body. Despite data from in vitro and in vivo preclinical studies, as well as human specimen studies indicating the crucial role played by angiogenesis in PCa, angiogenesis inhibition in clinical settings has not shown significant benefits to patients, thus challenging the inclusion and usefulness of antiangiogenic agents for the treatment of PCa. However, one of the apparent reasons why these antiangiogenic agents failed to meet expectations in PCa can be due to the choice of the antiangiogenic agents, because the majority of these drugs target vascular endothelial growth factor-A (VEGFA) and its receptors. The other relevant causes might be inappropriate drug combinations, the duration of treatment, and the method of endpoint determination. In this review, we will first discuss the role of angiogenesis in PCa growth and progression. We will then summarize the different angiogenic growth factors that influence PCa growth dynamics and review the outcomes of clinical trials conducted with antiangiogenic agents in PCa patients and, finally, critically assess the current status and fate of antiangiogenic therapy in this disease.

Incidence and risk of hypertension associated with vascular endothelial growth factor receptor tyrosine kinase inhibitors in cancer patients: a comprehensive network meta-analysis of 72 randomized controlled trials involving 30013 patients

Background

Tyrosine kinase inhibitors (TKIs) have been developed during the last decade that target the vascular endothelial growth factor receptor (VEGFR) are currently being evaluated as treatments for malignant tumors. The increased application of VEGFR-TKIs means that the probability of hypertension is a serious concern. However, the reported incidence varies markedly between clinical trials. Here, we undertook an up-to-date, comprehensive meta-analysis on clinical works to build the incidence of hypertension along with VEGFR-TKIs. The goal was to understand better of the overall venture of cancer patients’ hypertension treated with these drugs.

Methods

Databases (EMBASE, PubMed, and Cochrane library) and the abstracts of the American Society of Clinical Oncology annual meeting and European Society of Medical Oncology were searched to identify related studies. 95% confidence intervals (CIs), summary incidences, and relative risk (RR) were calculated utilizing either fixed-effects models on the basis of the heterogeneity of the included studies or random-effects.

Results

Seventy-two randomized controlled trials (including 30013 patients) were involved. The total incidence of high-grade and all-grade hypertensive events along with VEGFR-TKIs was 23.0% (95% CI, 20.1–26.0%) and 4.4% (95% CI, 3.7–5.0%), respectively. The use of VEGFR-TKIs remarkably enhanced the venture of developing high-grade (RR, 4.60; 95% CI, 3.92–5.40; P < 0.001) and all-grade (RR, 3.85; 95% CI, 3.37–4.40; P < 0.001) hypertensive events. Subgroup analyses revealed that the risk of a hypertensive event varied significantly in accordance with tumor type, VEGFR-TKI, trial phase, VEGFR-TKIs-based regimen, control therapy, and chemotherapy regimen.

Conclusions

Patients with cancer that receive VEGFR-TKIs are at a remarkable venture of developing hypertension. Therefore, suitable treatment and monitoring should be introduced to avoid cardiovascular complications.

Cardiovascular diseases in patients receiving small molecules with anti-vascular endothelial growth factor activity: A meta-analysis of approximately 29,000 cancer patients

Background

Targeted therapy with tyrosine kinase inhibitors with anti-vascular endothelial growth factor activity improves survival of cancer patients. Cardiovascular complications are critical and it is unknown whether these require specific treatment strategies. We aimed to clarify the associated risk of cardiovascular adverse events in patients treated with tyrosine kinase inhibitors.

Design

The design of this study was a meta-analysis of randomised controlled trials.

Methods

We searched PubMed, Cochrane, EMBASE and Web of Science databases for randomised controlled trials published until January 2017 that assessed patients with different types of cancer treated with or without tyrosine kinase inhibitors in addition to standard chemotherapy.

Results

A total of 29,252 patients from 71 randomised controlled trials were included. Tyrosine kinase inhibitor treatment was associated with a higher cardiac ischaemia relative risk (relative risk = 1.69; 95% confidence interval: 1.12–2.57; p = 0.01), with the highest risks observed for sorafenib and patients with renal cancer. Risk of thrombocytopaenia (relative risk = 2.2; 95% confidence interval: 1.73–2.79; p < 0.001) was highest for regorafenib and patients with breast cancer. Left ventricular systolic dysfunction was increased after tyrosine kinase inhibitor therapy (relative risk = 2.53; 95% confidence interval:1.79 – 3.57; p < 0.001), with the highest risks reported for sunitinib and hepatocellular cancer. QT corrected interval prolongation (relative risk = 6.25; 95% confidence interval: 3.44–11.38; p < 0.001) and arterial hypertension (relative risk = 3.78; 95% confidence interval: 3.15-4.54; p < 0.001) were reported. The relative risks of arterial adverse events, cerebral ischaemia, venous adverse events and pulmonary embolism were similar across groups.

Conclusion

Tyrosine kinase inhibitors increase the risk of severe cardiovascular and particularly thrombotic adverse events. Specific treatment regimens when prescribing tyrosine kinase inhibitor therapies appear desirable.

Early use of chemotherapy in metastatic prostate cancer

Since 2010, five new antineoplastic therapies have been FDA approved for the treatment of metastatic prostate cancer. With additional treatment options, questions arose about the optimal sequence of these agents. Until recently, chemotherapy has been deferred until later in the disease course in favor of next-generation androgen deprivation therapy. Prior to the development of abiraterone acetate and enzalutamide, clinical trials were opened investigating the combination of chemotherapy with androgen deprivation therapy in patients with metastatic hormone-sensitive disease. With the development of new oral therapies used to treat castration-resistant disease, these trials were largely forgotten or felt to be obsolete. Recently, two trials have been reported showing an overall survival benefit of the early use of chemotherapy in patients with hormone-naive prostate cancer, changing the treatment paradigm for metastatic disease. Here we review the history of chemotherapy in treating prostate cancer and the emerging evidence favoring its use as first-line therapy against metastatic hormone-sensitive disease.

[Prostate cancer microenvironment: Its structure, functions and therapeutic applications]

INTRODUCTION

In the field of prostate cancer there is a growing tendency for more and more studies to emphasise the predominant role of the zone situated between the tumour and the host: the tumour microenvironment. The aim of this article is to describe the structure and the functions of the prostate cancer microenvironment as well as the principal treatments that are being applied to it.

MATERIAL AND METHODS

PubMed and ScienceDirect databases have been interrogated using the association of keywords "tumour microenvironment" and "neoplasm therapy" along with "microenvironnement tumoral" and "traitements". Of the 593 articles initially found, 50 were finally included.

RESULTS

The tumour microenvironment principally includes host elements that are diverted from their primary functions and encourage the development of the tumour. In it we find immunity cells, support tissue as well as vascular and lymphatic neovascularization. Highlighting the major role played by this microenvironment has led to the development of specific treatments, notably antiangiogenic therapy and immunotherapy.

CONCLUSION

The tumour microenvironment, the tumour and the host influence themselves mutually and create a variable situation over time. Improvement of the knowledge of the prostate cancer microenvironment gradually enables us to pass from an approach centred on the tumour to a broader approach to the whole tumoral ecosystem. This enabled the emergence of new treatments whose place in the therapeutic arsenal still need to be found.

Repositioning "old" drugs for new causes: identifying new inhibitors of prostate cancer cell migration and invasion

The majority of prostate cancer (PCa) deaths occur due to the metastatic spread of tumor cells to distant organs. Currently, there is a lack of effective therapies once tumor cells have spread outside the prostate. It is therefore imperative to rapidly develop therapeutics to inhibit the metastatic spread of tumor cells. Gain of cell motility and invasive properties is the first step of metastasis and by inhibiting motility one can potentially inhibit metastasis. Using the drug repositioning strategy, we developed a cell-based multi-parameter primary screening assay to identify drugs that inhibit the migratory and invasive properties of metastatic PC-3 PCa cells. Following the completion of the primary screening assay, 33 drugs were identified from an FDA approved drug library that either inhibited migration or were cytotoxic to the PC-3 cells. Based on the data obtained from the subsequent validation studies, mitoxantrone hydrochloride, simvastatin, fluvastatin and vandetanib were identified as strong candidates that can inhibit both the migration and invasion of PC-3 cells without significantly affecting cell viability. By employing the drug repositioning strategy instead of a de novo drug discovery and development strategy, the identified drug candidates have the potential to be rapidly translated into the clinic for the management of men with aggressive forms of PCa.

Chemotherapy options in castration-resistant prostate cancer

Introduction:

The treatment landscape for patients with metastatic castration-resistant prostate cancer (CRPC) is evolving, with recent approvals of immune therapy, novel hormonal therapy, and bone-targeted therapy. Chemotherapy remains an essential component of the armamentarium. Herein, we review current chemotherapy options for patients with CRPC and discuss future challenges.

Methods:

We reviewed literature for chemotherapy agents in prostate cancer, with special attention to the evidence for efficacy of the currently approved agents. We also reviewed emerging data on biomarkers of response to chemotherapy for CRPC.

Results:

Taxanes, especially docetaxel and cabazitaxel, have first- and second-line indications for CRPC, respectively, with both providing a survival benefit. Multiple attempts to improve on the single agent efficacy of docetaxel with combination therapy have not generally been successful although platinum combinations are used for resistant phenotypes. Reductions in prostate-specific antigen by ≥30% and reductions in circulating tumor cells (CTCs) to ≤ 5 are associated with improved survival on chemotherapy. Chemotherapy may continue to be effective therapy for patients with biomarkers that are associated with resistance to androgen-directed therapies (androgen receptor splice variant 7 positivity in CTCs or high CTC heterogeneity).

Conclusions:

Chemotherapy remains an essential component of CRPC therapy, and biomarkers are being identified to define clinical scenarios where chemotherapy may be the optimal therapy choice.

Risk of Gastrointestinal Events During Vandetanib Therapy in Patients With Cancer: A Systematic Review and Meta-analysis of Clinical Trials

Vandetanib, a tyrosine kinase inhibitor used as an anticancer therapeutic agent, has adverse events associated with treatment resulting in noncompliance and withdrawal from the therapy. Here, we performed meta-analysis of published clinical trials to determine relative risk (RR) and incidence of gastrointestinal events during vandetanib therapy in patients with cancer. A comprehensive literature search was performed and summary incidence, RR, and 95% confidence intervals (CIs) were calculated employing fixed- or random-effects models, depending on the heterogeneity of trials. Twenty-two trials with 6382 patients were included summary incidences of all-grade gastrointestinal events in patients with cancer were anorexia 24% (95% CI, 20%-28%), constipation 17% (95% CI, 13%-20%), diarrhea 46% (95% CI, 40%-53%), nausea 29% (95% CI, 25%-33%), and vomiting 17% (95% CI, 14%-21%). Incidences of vandetanib-associated gastrointestinal events stratified by tumor histology were statistically insignificant. Vandetanib was associated with a significant risk of all-grade diarrhea (RR 1.75, 95% CI, 1.42-2.16) and high-grade diarrhea (RR 1.94, 95% CI, 1.43-2.64) and significantly decreased risk of all-grade constipation (RR 0.80, 95% CI, 0.71-0.91). Summary RR showed a significant risk of vandetanib-associated constipation (RR 0.82, 95% CI, 0.72-0.93) and diarrhea (all-grade: RR 1.68, 95% CI, 1.31-2.14 and high-grade: RR 1.57, 95% CI, 1.14-2.17) in patients with non-small-cell lung cancer. This study revealed a significantly increased risk of diarrhea and a reduced risk of constipation in patients with cancer receiving vandetanib, suggesting that appropriate and frequent clinical monitoring should be emphasized.

Hepatotoxicity with vascular endothelial growth factor receptor tyrosine kinase inhibitors: A meta-analysis of randomized clinical trials

A meta-analysis of randomized controlled trials (RCT) was conducted to determine the relative risk (RR) of hepatotoxicity with vascular endothelial growth factor receptor (VEGFR) tyrosine kinase inhibitors (TKI). Citations from PubMed/Medline, abstracts from major conferences, clinicaltrials.gov and package inserts were reviewed to include RCTs comparing arms with or without a VEGFR TKI. The RRs of all-grade ALT, AST, ALP and bilirubin elevation in 18,282 patients from 52 trials were 1.57 (95% CI 1.38-1.79, p<0.001), 1.57 (95% CI 1.36-1.81, p<0.001), 1.20 (95% CI 1.09-1.83, p<0.001) and 1.55 (95% CI 1.21-1.97, p<0.001) respectively, and high-grade elevations were 1.66 (95% CI 1.25-2.20, p=0.001), 1.61 (95% CI 1.21-2.14, p=0.001), 1.02 (95% CI 0.70-1.47, p=0.932) and 1.34 (95% CI 1.0-1.81, p=0.054) respectively compared to those in the non-TKI group. The incidence of hepatic failure with VEGFR TKIs was 0.8%.

Docetaxel-based therapy with and without antiangiogenic agents as first-line chemotherapy for castration-resistant prostate cancer: A meta-analysis of nine randomized controlled trials

The aim of this study was to systematically assess the effectiveness and safety of the addition of antiangiogenic agents to docetaxel-based chemotherapy for the treatment of castration-resistant prostate cancer. Computerized electronic databases, including Embase, PubMed and The Cochrane Library were searched for randomized controlled trials (RCTs) on the comparison between docetaxel-based therapy with and without antiangiogenic agents for the treatment of prostate cancer. The search time limit was from the building of the database until July 18, 2013. Following extracting information and conducting a methodological quality evaluation for study inclusion based on inclusion and exclusion criteria, RevMan 5.2 and Stata 12.0 software were used to perform a meta-analysis and the Jadad scale was used for evaluation of study quality. A total of 9 RCTs and 4,681 patients were included in this meta-analysis. The comparison between docetaxel-based therapy with and without antiangiogenic agents revealed no statistically significant differences regarding prostate-specific antigen response rate [risk ratio (RR)=0.99, 95% confidence interval (CI): 0.87-1.12, P=0.84], overall survival (OS) [hazard ratio (HR)=0.97, 95%CI: 0.91-1.05)] and progression-free survival (PFS) (HR=0.99, 95%CI: 0.83-1.18); however, the incidence of treatment-related mortality was higher in the docetaxel-based therapy with antiangiogenic agents group (RR=1.95, 95%CI: 1.23-3.11, P=0.005), whereas the incidence of thrombus formation was higher in the docetaxel-based therapy without antiangiogenic agents group (RR=0.57, 95%CI: 0.41-0.80, P=0.001). In conclusion, our findings indicated that docetaxel combined with antiangiogenic agents did not increase the OS or the PFS of the patients with castration-resistant prostate cancer, whereas it may increase the risk of treatment-related mortality. However, further RCTs with larger, high-quality patient samples are required to verify these findings.

Risk of treatment-related deaths with vascular endothelial growth factor receptor tyrosine kinase inhibitors: a meta-analysis of 41 randomized controlled trials

Background

Vascular endothelial growth factor receptor (VEGFR) tyrosine kinase inhibitors (TKIs) have widely been used in advanced cancer. However, these drugs may also lead to serious adverse events. The present meta-analysis aimed to determine the overall incidence and risk of deaths due to VEGFR-TKIs with more detailed subgroup analysis.

Materials and methods

PubMed, Web of Science, and Cochrane databases were searched for randomized controlled trials (RCTs) that compared VEGFR-TKIs with non-VEGFR-TKIs in the treatment of solid cancer. Pooled incidence, odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using random-effects or fixed-effects models based on the heterogeneity of included trials.

Results

A total of 14,139 participants from 41 RCTs were enrolled. The pooled incidence of death due to VEGFR-TKIs was 1.9% (95% CI: 1.6%–2.3%) with an OR of 1.85 (95% CI: 1.33–2.58; P<0.01) when compared with control groups. On subgroup analysis, significantly increased risk of death was found in patients with nonsmall-cell lung cancer (OR: 2.37; 95% CI: 1.19–4.73; P=0.01) and colorectal cancer (OR: 2.84; 95% CI: 1.02–7.96; P=0.05). Among different VEGFR-TKIs, sorafenib and sunitinib had significant risk of death when compared with control arms, respectively. VEGFR-TKIs in combination with other antineoplastic agents, but not VEGFR-TKI monotherapy, significantly increased the risk of treatment-related deaths. No heterogeneity was noted across all the prespecified subgroups regarding ORs.

Conclusion

The present work pointed out a significantly increased risk of death due to VEGFR-TKIs. Close monitoring should be emphasized in patients receiving these drugs.

Docetaxel and atrasentan versus docetaxel and placebo for men with advanced castration-resistant prostate cancer (SWOG S0421): a randomised phase 3 trial

BACKGROUND

The endothelin pathway has a role in bone metastases, which are characteristic of advanced prostate cancer. Atrasentan, an endothelin receptor antagonist, has shown activity in prostate cancer. We therefore assessed its effect on survival in patients with castration-resistant prostate cancer with bone metastases.

METHODS

In a double-blind phase 3 trial, men with metastatic castration-resistant prostate cancer, stratified for progression type (prostate-specific antigen or radiological), baseline pain, extraskeletal metastases, and bisphosphonate use, were randomly assigned in a 1:1 ratio to docetaxel (75 mg/m(2) every 21 days, intravenously) with atrasentan (10 mg/day, orally) or placebo for up to 12 cycles and treated until disease progression or unacceptable toxicity. Patients who did not progress on treatment were permitted to continue atrasentan or placebo for up to 52 weeks. Coprimary endpoints were progression-free survival (PFS) and overall survival. Analysis was by intention to treat. This trial is registered with ClinicalTrials.gov, number NCT00134056.

FINDINGS

498 patients were randomly assigned to the atrasentan group and 496 to the placebo group. The trial was halted early for futility in April, 2011, after a planned interim analysis. Median PFS was 9·2 months (95% CI 8·5-9·9) in the atrasentan group and 9·1 months (8·4-10·2) in the placebo group (hazard ratio 1·02, 0·89-1·16; p=0·81). Median overall survival was 17·8 months (16·4-19·8) in the atrasentan group versus 17·6 months (16·4-20·1) in the placebo group (1·04, 0·90-1·19; p=0·64). 278 (57%) of 492 patients in the atrasentan group had grade 3 and greater toxicity compared with 294 (60%) of 486 in the placebo group (p=0·22). Three deaths in the atrasentan group and seven in the placebo group were judged to be possibly or probably due to protocol treatment.

INTERPRETATION

Atrasentan, when added to docetaxel, does not improve overall survival or PFS in men with castration-resistant prostate cancer and bone metastases; therefore, single-agent docetaxel should remain as one of the standard treatments.

FUNDED

National Cancer Institute, Sanofi-Aventis, and Abbott Laboratories.

Incidence and risk of hypertension with vandetanib in cancer patients: a systematic review and meta-analysis of clinical trials

AIM

To perform a systematic review and meta-analysis of published clinical trials to determine incidence rate and overall risk of hypertension with vandetanib in cancer patients.

METHODS

A comprehensive literature search for studies published up to March 2012 was performed. Summary incidence rates, relative risk (RR), and 95% confidence intervals (CI) were calculated employing fixed- or random-effects models depending on the heterogeneity of the included trials.

RESULTS

A total of 11 trials with 3154 patients were included for the meta-analysis. The summary incidences of all-grade and high-grade hypertension in patients with cancer were 24.2% [95% confidence interval (CI), 18.1-30.2%] and 6.4% (95% CI, 3.3-9.5%), respectively. Subgroup analysis demonstrated that the pooled incidences of all-grade and high-grade hypertension were 21.8% [95% CI, 15-30.5%] and 7.6% (95% CI, 2.8-18.8%), respectively, among non-small-cell lung cancer (NSCLC) patients, and 32.1% (95% CI: 27.3-37.3%) and 8.8% (5.9%-12.9%), respectively, among MTC patients, and 15.4 (95% CI: 3.2-33.7%) and 3.4% (95% CI: 1%-11.1%) respectively, among non-MTC/NSCLC tumors patients. Furthermore, vandetanib was associated with a significant increased risk of all-grade hypertension (RR 5.1, 95% CI: 3.76-6.92, P = 0.000) and high-grade hypertension (RR 8.06, 95% CI: 3.41-19.04, P = 0.000) in comparison with controls.

CONCLUSIONS

There is a significant risk of developing hypertension in cancer patients receiving vandetanib. Appropriate monitoring and treatment is strongly recommended to prevent cardiovascular complications.

The potential role of aerobic exercise to modulate cardiotoxicity of molecularly targeted cancer therapeutics

Molecularly targeted therapeutics (MTT) are the future of cancer systemic therapy. They have already moved from palliative therapy for advanced solid malignancies into the setting of curative-intent treatment for early-stage disease. Cardiotoxicity is a frequent and potentially serious adverse complication of some targeted therapies, leading to a broad range of potentially life-threatening complications, therapy discontinuation, and poor quality of life. Low-cost pleiotropic interventions are therefore urgently required to effectively prevent and/or treat MTT-induced cardiotoxicity. Aerobic exercise therapy has the unique capacity to modulate, without toxicity, multiple gene expression pathways in several organ systems, including a plethora of cardiac-specific molecular and cell-signaling pathways implicated in MTT-induced cardiac toxicity. In this review, we examine the molecular signaling of antiangiogenic and HER2-directed therapies that may underpin cardiac toxicity and the hypothesized molecular mechanisms underlying the cardioprotective properties of aerobic exercise. It is hoped that this knowledge can be used to maximize the benefits of small molecule inhibitors, while minimizing cardiac damage in patients with solid malignancies.

Venous thromboembolic events with vascular endothelial growth factor receptor tyrosine kinase inhibitors: a systematic review and meta-analysis of randomized clinical trials

A trial-level meta-analysis was conducted to determine the relative risk (RR) of venous thromboembolic events (VTEs) associated with approved vascular endothelial growth factor receptor (VEGFR) tyrosine kinase inhibitors (TKI). Eligible studies included randomized phase 2 and 3 trials comparing arms with and without a Food and Drug Administration-approved VEGFR TKI (sunitinib, sorafenib, pazopanib, vandetanib, and axitinib). Statistical analyses calculated the RR and 95% confidence intervals (CI), using random-effects or fixed-effects models based on heterogeneity. A total of 7441 patients from 9 phase III trials and 8 phase II trials were selected. The RR of all grade and high-grade VTEs for the TKI vs. no TKI arms was 1.10 (95% CI 0.73-1.66, p=0.64) and 0.85 (95% CI: 0.58-1.25, p=0.41), respectively. No difference in risk was found based on tumor type, age and trial design. The majority of trials exhibited high quality per Jadad scoring and no heterogeneity or publication bias was found.

Risk of venous thromboembolic events associated with VEGFR-TKIs: a systematic review and meta-analysis

Vascular endothelial growth factor receptor (VEGFR) tyrosine kinase inhibitors (TKIs) have been widely used in advanced cancers. Concerns have arisen regarding the risk of venous thromboembolism with the use of these drugs. Currently, the contribution of VEGFR-TKIs to venous thromboembolism is still unknown. We performed a meta-analysis to determine the incidence and relative risk (RR) of venous thromboembolism events (VTEs) associated with these agents. Eligible studies included phase II and III prospective trials evaluating US Food and Drug Administration approved VEGFR-TKIs (pazopanib, sunitinib, sorafenib and vandetanib), and data on VTEs were available. Overall incidence rates, RR and 95% confidence intervals (CI) were calculated employing fixed- or random-effects models depending on the heterogeneity of included trials. A total of 14 studies (4,430 patients) were selected for this meta-analysis. The incidence of VTEs related to VEGFR-TKIs was 3% (95%CI: 1.7-5.1%), and there was no statistically significant increase in the risk of VTEs for VEGFR-TKIs versus controls in overall population (RR0.912, 95%CI: 0.617-1.348, p = 0.643). On subgroup analysis, no significant increase in the risk of VTEs was found among different VEGFR-TKIs or tumor types. No evidence of publication bias was observed. The use of VEGFR-TKIs does not significantly increase the risk of VTEs, the risk of VTEs in patients with cancer is driven predominantly by tumor types, host factors and concomitant usage of anticancer agents. These results would provide important information for clinicians who use VEGFR-TKIs to treat patients with solid cancer.

Addition of vandetanib to chemotherapy in advanced solid cancers: a meta-analysis

The addition of vandetanib to chemotherapy has been shown to have a marked effect on patients with advanced cancers who had failed previous chemotherapy. We carried out a meta-analysis to determine the efficacy and safety of vandetanib compared with chemotherapy in patients with advanced cancers. For this meta-analysis, we selected randomized clinical trials that compared vandetanib-based therapy (VBT) with the matched chemotherapy or placebo alone in patients with advanced cancers. The outcomes included overall survival (OS), progression-free survival (PFS), the objective response rate, and toxicities. Hazard ratios (HRs) and odds ratios were reported with 95% confidence intervals (CIs). A total of 14 eligible trials were included for the meta-analysis, with 2995 patients in the VBT group and 2479 patients in the control group. A significant improvement was observed in PFS (HR 0.76, 95% CI 0.68-0.86 in all cancers, HR 0.80, 95% CI 0.70-0.90 in lung cancer, HR 0.54, 95% CI 0.40-0.74 in thyroid cancer) and in objective response rate (odds ratio 2.09, 95% CI 1.42-3.07) in the VBT group. However, no significant difference was found in OS (HR 0.96, 95% CI 0.90-1.03). The subgroups of patients with non-small-cell lung cancer who benefited from vandetanib therapy were identified as those with a history of smoking (HR 0.87, 95% CI 0.80-0.95) and an adenocarcinoma histology (HR 0.85, 95% CI 0.77-0.94). In addition, patients who received VBT had an increased incidence of adverse events such as rash, diarrhea, and neutropenia. The addition of vandetanib to chemotherapy significantly improves PFS in patients with locally advanced or metastatic cancers, especially lung and thyroid cancer.

The VEGF pathway in cancer and disease: responses, resistance, and the path forward

Antiangiogenesis was proposed as a novel target for the treatment of cancer 40 years ago. Since the original hypothesis put forward by Judah Folkman in 1971, factors that mediate angiogenesis, their cellular targets, many of the pathways they signal, and inhibitors of the cytokines and receptors have been identified. Vascular endothelial growth factor (VEGF) is the most prominent among the angiogenic cytokines and is believed to play a central role in the process of neovascularization, both in cancer as well as other inflammatory diseases. This article reviews the biology of VEGF and its receptors, the use of anti-VEGF approaches in clinical disease, the toxicity of these therapies, and the resistance mechanisms that have limited the activity of these agents when used as monotherapy.

Vandetanib for the treatment of metastatic medullary thyroid cancer

Medullary thyroid cancer (MTC) represents an aggressive form of thyroid malignancy. Some may occur spontaneously or can be associated with Multiple Endocrine Neoplasia syndromes, or Familial Medullary Thyroid Cancer syndrome. In these patients, the protooncogene RET (rearranged during transfection) is mutated. In patients who have unresectable or metastatic disease, the long term prognosis is poor. New treatments for this disease have focused on the use of targeted agents that inhibit the receptor tyrosine kinase of RET. One of these treatments, Vandetanib (Caprelsa, Astra Zeneca), recently has received approval from the Food and Drug Administration for the treatment of patients with progressive locally advanced and/or metastatic disease. This review highlights the studies that led to the drug's approval, and discusses on the potential financial costs of treatment and side effects of this therapy. The main clinical studies evaluating Vandetanib for the treatment of other solid tumors will also be reviewed.

Contrasted effects of the multitarget TKi vandetanib on docetaxel-sensitive and docetaxel-resistant prostate cancer cell lines

OBJECTIVES

Overexpression of epidermal growth factor receptor (EGFR) and angiogenic factors is associated with the progression of androgen-independent prostate cancer (AIPC). We examined the effects of vandetanib, an inhibitor of vascular endothelial growth factor (VEGFR), EGFR, and rearranged during transfection (RET) tyrosine-kinase activities, alone or combined with docetaxel, on PC3 docetaxel-sensitive (PC3wt) or docetaxel-resistant (PC3R) AIPC cell growth in vivo and in vitro.

METHODS

Mice bearing PC3wt or PC3R tumors were treated for 3 weeks with vandetanib (25 or 50 mg/kg/d p.o., 5 d/wk), docetaxel (10 or 30 mg/kg i.p., 1 d/wk), or their combination (low or high doses). Xenograft tumors were analyzed for expression of Ki-67, EGFR, VEGFR2, and production of VEGFA.

RESULTS

On PC3wt, vandetanib at both doses stimulated tumor growth, whereas docetaxel at both doses exerted strong growth-inhibiting effects. The low-dose vandetanib-docetaxel combination resulted in tumor growth similar to that of control, whereas the high-dose combination induced a significant antiproliferative effect. In contrast, on PC3R, the low-dose of vandetanib had no effect on tumor growth, whereas the high-dose of vandetanib significantly inhibited tumor growth. Docetaxel at both doses exerted moderate and transient antitumor effects. The combination of high-dose vandetanib with high-dose docetaxel resulted in antiproliferative effects, which were lower than expected from the sum of individual drug effects. Importantly, tumor analyses revealed overexpression of the EGFR/VEGFR pathways in PC3R relative to PC3wt.

CONCLUSION

Present results suggest that vandetanib should not be associated with docetaxel in treatment-naive or docetaxel-resistant prostate cancer (CaP). The use of high-dose vandetanib alone may warrant further investigation in patients with docetaxel-resistant AIPC overexpressing VEGFR/EGFR pathways.

Incidence and risk of QTc interval prolongation among cancer patients treated with vandetanib: a systematic review and meta-analysis

BACKGROUND

Vandetanib is a multikinase inhibitor that is under assessment for the treatment of various cancers. QTc interval prolongation is one of the major adverse effects of this drug, but the reported incidence varies substantially among clinical trials. We performed a systematic review and meta-analysis to obtain a better understanding in the risk of QTc interval prolongation among cancer patients administered vandetanib.

METHODOLOGY AND PRINCIPAL FINDINGS

Eligible studies were phase II and III prospective clinical trials that involved cancer patients who were prescribed vandetanib 300 mg/d and that included data on QTc interval prolongation. The overall incidence and risk of QTc interval prolongation were calculated using random-effects or fixed-effects models, depending on the heterogeneity of the included studies. Nine trials with 2,188 patients were included for the meta-analysis. The overall incidence of all-grade and high-grade QTc interval prolongation was 16.4% (95% CI, 8.1-30.4%) and 3.7% (8.1-30.4%), respectively, among non-thyroid cancer patients, and 18.0% (10.7-28.6%) and 12.0% (4.5-28.0%), respectively, among thyroid cancer patients. Patients with thyroid cancer who had longer treatment duration also had a higher incidence of high-grade events, with a relative risk of 3.24 (1.57-6.71), than patients who had non-thyroid cancer. Vandetanib was associated with a significantly increased risk of all-grade QTc interval prolongation with overall Peto odds ratios of 7.26 (4.36-12.09) and 5.70 (3.09-10.53) among patients with non-thyroid cancer and thyroid cancer, respectively, compared to the controls.

CONCLUSIONS/SIGNIFICANCE

Treatment with vandetanib is associated with a significant increase in the overall incidence and risk of QTc interval prolongation. Different cancer types and treatment durations may affect the risk of developing high-grade QTc interval prolongation.

Stevens-johnson syndrome induced by vandetanib

Vandetanib is a once-daily oral anticancer drug that selectively inhibits key signaling pathways in cancer by targeting vascular endothelial growth factor receptors, epidermal growth factor receptors tyrosine kinase, and rearranged during transfection-dependent tumor cell proliferation and survival. The most frequently reported adverse events attributed to vandetanib include diarrhea, elevated aminotransferase, asymptomatic corrected QT interval prolongation, and hypertension. Though a number of randomized, doubleblind studies, including cutaneous adverse events attributed to vandetanib, have been reported along with these general symptoms, no case of Stevens-Johnson syndrome (SJS) has been reported. This paper demonstrates a case of SJS induced by vandetanib.

Vandetanib: first global approval

Vandetanib is an orally active antagonist of vascular endothelial growth factor (VEGF) receptor-2 (VEGFR-2), epidermal growth factor receptor (EGFR or HER1 or ErbB1) and RET kinase, and is now available in the US for the treatment of metastatic medullary thyroid cancer (MTC). Regulatory submissions for this indication have been filed in the EU and Canada, with clinical development in malignant MTC ongoing in several other countries. Vandetanib is being developed by AstraZeneca, and is also in phase II development for biliary, breast and prostate cancer. Earlier, AstraZeneca withdrew regulatory filings for non-small cell lung cancer (NSCLC) in the US and EU, and later discontinued development. This article summarizes the milestones in the development of vandetanib leading to this first approval in malignant MTC.

Castration-resistant prostate cancer: many treatments, many options, many challenges ahead

Although the long natural history of prostate cancer presents challenges in the development of novel therapeutics, major contributions have been observed recently. A better understanding of the long-term complications of androgen deprivation has changed the initial approach to most patients with advanced disease. Specifically, recognition of the limitations of prostate-specific antigen has driven the pursuit of new tools capable of becoming true surrogates for disease outcome. Understanding the molecular biology of castration-resistant prostate cancer (CRPC) has led to a dramatic paradigm shift in the treatment of patients with metastatic disease where the androgen receptor becomes a central therapeutic target. Specific adrenal inhibitors and engineered super androgen receptor inhibitors have become the most promising agents in the disease. Novel immune therapies have been shown to improve survival in selected patients with castration-resistant disease despite the inability to impact traditional markers of response. Similarly, agents such as cabazitaxel and abiraterone acetate have demonstrated clinical benefit are now a standard of care in docetaxel-refractory metastatic CRPC patients. All these changes have occurred in a relatively short period and are likely to change the prostate cancer treatment paradigm. This review summarizes the current management of CRPC and discusses potential future directions.

Ten years of docetaxel-based therapies in prostate adenocarcinoma: a systematic review and meta-analysis of 2244 patients in 12 randomized clinical trials

BACKGROUND

Chemotherapy can reduce serum prostate-specific antigen (PSA) levels and relieve pain in some patients with castration-resistant prostate cancer (CRPC). To improve therapeutic efficacy numerous randomized trials have investigated docetaxel-based combination regimens. The present analysis tries to overcome the statistical limitations of the individual trials and investigates the treatment effects in total and in various combination groups.

METHODS

The Medline, Embase, Cancerlit, and American Society of Clinical Oncology Abstract databases were searched for published randomized placebo-controlled trials evaluating the use of docetaxel-based regimens in patients with CRPC. The outcomes assessed were overall survival, overall response rate, PSA response rate, and adverse effects.

RESULTS

Twelve articles (2244 participants) were included in the meta-analysis. The analysis demonstrates a higher PSA response rate from docetaxel-based combinations when compared with docetaxel alone (relative risk [RR] = 1.16; P = .010). The estimated median survival in docetaxel-based combinations was statistically significantly longer than in the docetaxel-alone group (22.0 vs. 18.4 months; P = .037). Grade 3 or 4 neutropenia as well as grade 3 or 4 thromboembolic events were similar in both arms (overall RR, 0.87 [confidence interval (CI) 0.71-1.07]; P = .20 and overall RR 1.52 [0.79 - 2.90]; P = .21, respectively).

CONCLUSION

The analysis of 12 randomized trials provides evidence in favor of docetaxel-based combination chemotherapy for patients with CRPC and good performance status.

The changing therapeutic landscape of castration-resistant prostate cancer

Castration-resistant prostate cancer (CRPC) has a poor prognosis and remains a significant therapeutic challenge. Before 2010, only docetaxel-based chemotherapy improved survival in patients with CRPC compared with mitoxantrone. Our improved understanding of the underlying biology of CRPC has heralded a new era in molecular anticancer drug development, with a myriad of novel anticancer drugs for CRPC entering the clinic. These include the novel taxane cabazitaxel, the vaccine sipuleucel-T, the CYP17 inhibitor abiraterone, the novel androgen-receptor antagonist MDV-3100 and the radioisotope alpharadin. With these developments, the management of patients with CRPC is changing. In this Review, we discuss these promising therapies along with other novel agents that are demonstrating early signs of activity in CRPC. We propose a treatment pathway for patients with CRPC and consider strategies to optimize the use of these agents, including the incorporation of predictive and intermediate end point biomarkers, such as circulating tumor cells.

EGFR Targeting in Hormone-Refractory Prostate Cancer: Current Appraisal and Prospects for Treatment

The incidence of prostate cancer increases with age and because of its high prevalence this disease has become a major public health concern. Despite advances in our understanding of the biological mechanisms responsible for the development of this cancer, the transition to the hormone refractory stage (HRPC) and metastatic progression pose real problems of clinical management. Currently, docetaxel chemotherapy has been shown to have a slight but significant impact on survival, though the gain in median survival is still less than three months. Research is therefore continuing to improve treatment outcomes. The progression of prostate cancer is accompanied by the overexpression of EGFR (epidermal growth factor receptor) in a very large majority of cases, suggesting that this may play a mechanistic role. Unfortunately, although preclinical findings seem to be promising for therapies targeting the EGFR in HRPC, current clinical results are disappointing. These results should however encourage us to look for different ways of using anti-EGFR agents or combining them with other targeted therapies.