Phase 2 study of neoadjuvant docetaxel plus bevacizumab in patients with high-risk localized prostate cancer: a Prostate Cancer Clinical Trials Consortium trial

The Association Between [68Ga]PSMA PET/CT Response and Biochemical Progression in Patients with High-Risk Prostate Cancer Receiving Neoadjuvant Therapy

Our previous study found that the prostate-specific membrane antigen (PSMA) PET/CT response of primary prostate cancer (PCa) to neoadjuvant therapy can predict the pathologic response. This study was designed to investigate the association between [68Ga]PSMA PET/CT changes and biochemical progression-free survival (bPFS) in high-risk patients who underwent neoadjuvant therapy before radical prostatectomy (RP). Methods: Seventy-five patients with high-risk PCa in 2 phase II clinical trials who received neoadjuvant therapy before RP were included. The patients received androgen deprivation therapy plus docetaxel (n = 33) or androgen deprivation therapy plus abiraterone (n = 42) as neoadjuvant treatment. All patients had serial [68Ga]PSMA PET/CT scans before and after neoadjuvant therapy. Age, initial prostate-specific antigen level, nadir prostate-specific antigen level before RP, tumor grade at biopsy, treatment regimen, clinical T stage, PET imaging features, pathologic N stage, and pathologic response on final pathology were included for univariate and multivariate Cox regression analyses to identify independent predictors of bPFS. Results: With a median follow-up of 30 mo, 18 patients (24%) experienced biochemical progression. Multivariate Cox regression analyses revealed that only SUVmax derived from posttreatment [68Ga]PSMA PET/CT and pathologic response on final pathology were independent factors for the prediction of bPFS, with hazard ratios of 1.02 (95% CI, 1.00-1.04; P = 0.02) and 0.12 (95% CI, 0.02-0.98; P = 0.048), respectively. Kaplan-Meier analysis revealed that patients with a favorable [68Ga]PSMA PET/CT response (posttreatment SUVmax < 8.5) or a favorable pathologic response (pathologic complete response or minimal residual disease) had a significantly lower rate of 3-y biochemical progression. Conclusion: Our results indicated that [68Ga]PSMA PET/CT response was an independent risk factor for the prediction of bPFS in patients with high-risk PCa receiving neoadjuvant therapy and RP, suggesting [68Ga]PSMA PET/CT to be an ideal tool to monitor response to neoadjuvant therapy.

Different predictive values of microvessel density for biochemical recurrence among different PCa populations: A systematic review and meta-analysis

BACKGROUND

Several studies have explored the relationship between intratumoral microvessel density (MVD) and the risk of postoperative biochemical recurrence (BCR) in prostate cancer (PCa), although the results are contradictory. Therefore, we conducted a meta-analysis to investigate the effect of MVD on BCR in PCa.

METHOD

We searched PubMed, MEDLINE, Science Direct/Elsevier, the Cochrane Library, CNKI, and EMBase databases from inception through January 2022, with no year or language restrictions, and used NOS guidelines to evaluate the quality of the 19 eligible studies. The derived hazard ratio (HR) and 95% confidence interval (95%CI) were used to assess each endpoint. Data synthesis was performed with RevMan to assess the prognostic value of MVD in PCa and its heterogeneity, while the publication bias was examined using STATA 16.0.

RESULTS

Our meta-analysis included 19 articles (4 for T1-2, 6 for T1-3, and 9 for T1-4) on postoperative biochemical recurrence of PCa, among which, 3933 patients were pooled. The predictive ability of intratumoral MVD for different stages of PCa on BCR was T1-2 (HR, 2.46; 95% CI, 1.08-5.58; p = 0.03; I²  = 83%), T1-3 (HR, 2.38, 95% CI, 1.41-4.01; p = 0.001; I²  = 82%), T1-4 (HR, 1.61; 95% CI, 1.19-2.19; p = 0.002; I²  = 61%).The subgroup analyses based on European and immunohistochemical antibody none-factor VII were consistent with primary one. Sensitivity analysis excluding those studies judged to be at high risk of bias in T1-2 showed a HR of 2.99[1.70,5.27] (I²  = 38%, p = 0.0001), demonstrating the robustness of risk estimates of MVD for the assessment of biochemical recurrence.

CONCLUSION

Microvessel density is a predictor of BCR among patients with PCa, and earlier T stage PCa with a stronger MVD is associated with BCR. Further studies are needed to investigate neoangiogenesis in different T stages of PCa and whether MVD will be of benefit to the EAU-recommended tool for biochemical recurrence risk assessment.

Trial Watch: Tumor-targeting monoclonal antibodies in cancer therapy

In 1997, for the first time in history, a monoclonal antibody (mAb), i.e., the chimeric anti-CD20 molecule rituximab, was approved by the US Food and Drug Administration for use in cancer patients. Since then, the panel of mAbs that are approved by international regulatory agencies for the treatment of hematopoietic and solid malignancies has not stopped to expand, nowadays encompassing a stunning amount of 15 distinct molecules. This therapeutic armamentarium includes mAbs that target tumor-associated antigens, as well as molecules that interfere with tumor-stroma interactions or exert direct immunostimulatory effects. These three classes of mAbs exert antineoplastic activity via distinct mechanisms, which may or may not involve immune effectors other than the mAbs themselves. In previous issues of OncoImmunology, we provided a brief scientific background to the use of mAbs, all types confounded, in cancer therapy, and discussed the results of recent clinical trials investigating the safety and efficacy of this approach. Here, we focus on mAbs that primarily target malignant cells or their interactions with stromal components, as opposed to mAbs that mediate antineoplastic effects by activating the immune system. In particular, we discuss relevant clinical findings that have been published during the last 13 months as well as clinical trials that have been launched in the same period to investigate the therapeutic profile of hitherto investigational tumor-targeting mAbs.

Animal models of chemotherapy-induced cognitive decline in preclinical drug development

RATIONALE

Chemotherapy-induced cognitive impairment (CICI), chemobrain, and chemofog are the common terms for mental dysfunction in a cancer patient/survivor under the influence of chemotherapeutics. CICI is manifested as short/long term memory problems and delayed mental processing, which interferes with a person's day-to-day activities. Understanding CICI mechanisms help in developing therapeutic interventions that may alleviate the disease condition. Animal models facilitate critical evaluation to elucidate the underlying mechanisms and form an integral part of verifying different treatment hypotheses and strategies.

OBJECTIVES

A methodical evaluation of scientific literature is required to understand cognitive changes associated with the use of chemotherapeutic agents in different preclinical studies. This review mainly emphasizes animal models developed with various chemotherapeutic agents individually and in combination, with their proposed mechanisms contributing to the cognitive dysfunction. This review also points toward the analysis of chemobrain in healthy animals to understand the mechanism of interventions in absence of tumor and in tumor-bearing animals to mimic human cancer conditions to screen potential drug candidates against chemobrain.

RESULTS

Substantial memory deficit as a result of commonly used chemotherapeutic agents was evidenced in healthy and tumor-bearing animals. Spatial and episodic cognitive impairments, alterations in neurotrophins, oxidative and inflammatory markers, and changes in long-term potentiation were commonly observed changes in different animal models irrespective of the chemotherapeutic agent.

CONCLUSION

Dyscognition exists as one of the serious side effects of cancer chemotherapy. Due to differing mechanisms of chemotherapeutic agents with differing tendencies to alter behavioral and biochemical parameters, chemotherapy may present a significant risk in resulting memory impairments in healthy as well as tumor-bearing animals.

Neoadjuvant Therapy in High-Risk Prostate Cancer

High-risk prostate cancer (PCa) is associated with higher rates of biochemical recurrence, clinical recurrence, metastasis, and PCa-specific death, compared to low-and intermediate-risk disease. Herein, we review the various definitions of high-risk PCa, describe the rationale for neoadjuvant therapy prior to radical prostatectomy, and summarize the contemporary data on neoadjuvant therapies. Since the 1990s, several randomized trials of neoadjuvant androgen deprivation therapy (ADT) have consistently demonstrated improved pathological parameters, specifically tumor downstaging and reduced extraprostatic extension, seminal vesicle invasion, and positive surgical margins without improvements in cancer-specific or overall survival. These studies, however, were not exclusive to high-risk patients and were limited by suboptimal follow-up periods. Newer studies of neoadjuvant ADT in high-risk PCa show promising pathological and oncological outcomes. Recent level 1 data suggests neoadjuvant chemohormonal therapy (CHT) may improve longer-term survival in high-risk PCa. Immunologic neoadjuvant trials are in their infancy, and further study is required. Neoadjuvant therapies may be promising additions to the multimodal therapeutic landscape of high-risk and locally advanced PCa in the near future.

Systemic treatments for high-risk localized prostate cancer

The majority of patients with prostate cancer who later develop lethal metastatic disease have high-risk localized disease at presentation, emphasizing the importance of effective treatment strategies at this stage. Multimodal treatment approaches that combine systemic and local therapies offer a promising strategy for improving the clinical outcomes of patients with high-risk localized prostate cancer. Combinations of neoadjuvant and adjuvant chemotherapy, hormonal therapy, or chemohormonal therapy are considered to be the standard of care in most solid tumours and should be investigated in the future for the treatment of prostate cancer to improve patient outcomes. However, although the combination of androgen deprivation therapy and radiotherapy is a standard of care in high-risk localized or locally advanced prostate cancer, the benefit of chemotherapy or chemohormonal therapy has yet to be demonstrated outside of the metastatic setting. Moreover, the benefit of neoadjuvant and/or adjuvant systemic therapies in combination with radical prostatectomy has not been proved. The development of next-generation hormonal agents, which have been approved for the treatment of castration-resistant prostate cancer, offers further therapeutic possibilities that are being assessed in early-phase clinical trials.

Docetaxel-loaded human serum albumin (HSA) nanoparticles: synthesis, characterization, and evaluation

Background

Docetaxel (DTX) is an anticancer drug that is currently formulated with polysorbate 80 and ethanol (50:50, v/v) in clinical use. Unfortunately, this formulation causes hypersensitivity reactions, leading to severe side-effects, which have been primarily attributed to polysorbate 80.

Methods

In this study, a DTX-loaded human serum albumin (HSA) nanoparticle (DTX-NP) was designed to overcome the hypersensitivity reactions that are induced by polysorbate 80. The methods of preparing the DTX-NPs have been optimized based on factors including the drug-to-HSA weight ratio, the duration of HSA incubation, and the choice of using a stabilizer. Synthesized DTX-NPs were characterized with regard to their particle diameters, drug loading capacities, and drug release kinetics. The morphology of the DTX-NPs was observed via scanning electron microscopy (SEM) and the successful preparation of DTX-NPs was confirmed via differential scanning calorimetry (DSC). The cytotoxicity and cellular uptake of DTX-NPs were investigated in the non-small cell lung cancer cell line A549 and the maximum tolerated dose (MTD) of DTX-NPs was evaluated via investigations with BALB/c mice.

Results

The study showed that the loading capacity and the encapsulation efficiency of DTX-NPs prepared under the optimal conditions was 11.2 wt% and 63.1 wt%, respectively and the mean diameter was less than 200 nm, resulting in higher permeability and controlled release. Similar cytotoxicity against A549 cells was exhibited by the DTX-NPs in comparison to DTX alone while higher maximum tolerated dose (MTD) with the DTX-NPs (75 mg/kg) than with DTX (30 mg/kg) was demonstrated in mice, suggesting that the DTX-NPs prepared with HSA yielded similar anti-tumor activity but were accompanied by less systemic toxicity than solvent formulated DTX.

Conclusions

DTX-NPs warrant further investigation and are promising candidates for clinical applications.

A systematic review of contemporary management of oligometastatic prostate cancer: fighting a challenge or tilting at windmills?

PURPOSE

Amongst the unanswered questions regarding prostate cancer (PCa), the optimal management of oligometastatic disease remains one of the major concerns of the scientific community. The very existence of this category is still subject to controversy. Aim of this systematic review is to summarize current available data on the most appropriate management of oligometastatic PCa.

EVIDENCE ACQUISITION

All relevant studies published in English up to November the 1st were identified through systematic searches in PubMed, EMBASE, Cochrane Library, CINAHL, Google Scholar and Ovid database. A search was performed including the combination of following words: (prostate cancer) and (metastatic) and [(oligo) or (PSMA) or (cytoreductive) or (stereotaxic radiotherapy) or (prostatectomy)]. 3335 articles were reviewed. After title screening and abstract reading, 118 papers were considered for full reading, leaving a total of 36 articles for the systematic review.

EVIDENCE SYNTHESIS

There is still no consensus on the definition of oligometastatic disease, nor on the imaging modalities used for its detection. While retrospective studies suggest an added benefit with the treatment the primitive tumor by cytoreductive prostatectomy (55% survival rate vs 21%, p < 0.001), prospective studies do not validate the same outcome. Nonetheless, most studies have reported a reduction in local complications after cytoreductive prostatectomy (< 10%) compared to the best systemic treatment (25-30%). Concerning radiotherapy, an overall survival benefit for patients with a low metastatic burden was found in STAMPEDE (HR 0.68, 95% CI 0.52-0.90; p = 0.007) and suggested in subgroup analysis of the HORRAD trial. Regarding the impact of metastases-directed therapy (MDT), the STOMP and ORIOLE trials suggested that metastatic disease control might improve androgen deprivation therapy-free survival (in STOMP: 21 vs 13 months for MDT vs standard of care). Nonetheless, the impact of MDT on long-term oncologic results remains unclear. Finally, oligometastatic disease appears to be a biologically different entity compared to high-burden metastatic disease. New findings on exosomes appear to make them intriguing biomarkers in the early phases of oligometastatic PCa.

CONCLUSION

Oligometastatic PCa is today a poorly understood disease. The implementation of new imaging techniques as whole-body MRI and PSMA PET/CT has increased exponentially the number of oligometastatic patients detected. Data of available trials suggest a benefit from cytoreductive prostatectomy to reduce local complication, though its impact on survival remains unknown. Radiotherapy may be beneficial for patients with low-burden metastatic PCa, while MDT may delay the need for androgen deprivation therapy. Results from ongoing trials data are eagerly awaited to draw reliable recommendations.

The addition of chemotherapy in the definitive management of high risk prostate cancer

In attempt to improve long-term disease control outcomes for high-risk prostate cancer, numerous clinical trials have tested the addition of chemotherapy (CTX)-either adjuvant or neoadjuvant-to definitive local therapy, either radical prostatectomy (RP) or radiation therapy (RT). Neoadjuvant trials generally confirm safety, feasibility, and pre-RP PSA reduction, but rates of pathologic complete response are rare, and no indications for neoadjuvant CTX have been firmly established. Adjuvant regimens have included CTX alone or in combination with androgen deprivation therapy (ADT). Here we provide a review of the relevant literature, and also quantify utilization of CTX in the definitive management of localized high-risk prostate cancer by querying the National Cancer Data Base. Between 2004 and 2013, 177 patients (of 29,659 total) treated with definitive RT, and 995 (of 367,570 total) treated with RP had CTX incorporated into their treatment regimens. Low numbers of RT + CTX patients precluded further analysis of this population, but we investigated the impact of CTX on overall survival (OS) for patients treated with RP +/- CTX. Disease-free survival or biochemical-recurrence-free survival are not available through the National Cancer Data Base. Propensity-score matching was conducted as patients treated with CTX were a higher-risk group. For nonmatched groups, OS at 5-years was 89.6% for the CTX group vs. 95.6%, for the no-CTX group (P < 0.01). The difference in OS between CTX and no-CTX groups did not persist after propensity-score matching, with 5-year OS 89.6% vs. 90.9%, respectively (Hazard ratio 0.99; P = 0.88). In summary, CTX was not shown to improve OS in this retrospective study. Multimodal regimens-such as RP followed by ADT, RT, and CTX; or RT in conjunction with ADT followed by CTX-have shown promise, but long-term follow-up of randomized data is required.

Systematic Review of Systemic Therapies and Therapeutic Combinations with Local Treatments for High-risk Localized Prostate Cancer

CONTEXT

Systemic therapies, combined with local treatment for high-risk prostate cancer, are recommended by the international guidelines for specific subgroups of patients; however, for many of the clinical scenarios, it remains a research field.

OBJECTIVE

To perform a systematic review, and describe current evidence and perspectives about the multimodal treatment of high-risk prostate cancer.

EVIDENCE ACQUISITION

We performed a systematic review of PubMED, Embase, Cochrane Library, European Society of Medical Oncology/American Society of Clinical Oncology Annual proceedings, and clinicalTrial.gov between January 2010 and February 2018 following the Preferred Reporting Items for Systematic Reviews and Meta-analysis statement.

EVIDENCE SYNTHESIS

Seventy-seven prospective trials were identified. According to multiple randomized trials, combining androgen deprivation therapy (ADT) with external-beam radiotherapy (EBRT) outperforms EBRT alone for both relapse-free and overall survival. Neoadjuvant ADT did not show significant improvement compared with prostatectomy alone. The role of adjuvant ADT after prostatectomy in patients with high-risk disease is still debated, with lack of data from phase 3 trials in pN0 patients. Novel androgen pathway inhibitors have been tested only in early-phase trials in addition to primary treatment. GETUG 12, RTOG 0521, and nonmetastatic subgroup of the STAMPEDE trial showed improved relapse-free survival for docetaxel in patients treated with EBRT plus ADT, although mature metastasis-free survival data are still pending. Both the SPCG-12 and the VACSP#553 trial showed no improvement in relapse-free survival for adjuvant docetaxel after prostatectomy.

CONCLUSIONS

In contrast to the clearly demonstrated survival benefits of long-term adjuvant ADT when used with EBRT, its role after prostatectomy remains unclear especially in pN0 patients. Adding docetaxel to EBRT-ADT improves relapse-free survival, with immature results on overall survival. Novel androgen receptor pathway inhibitors are currently being tested in the neoadjuvant and adjuvant setting.

PATIENT SUMMARY

Treatment of high-risk prostate cancer is based on a multimodality approach that includes systemic treatments. The best treatment or therapy combination remains to be defined.

Issues and promises of bevacizumab in prostate cancer treatment

INTRODUCTION

There is general agreement that increased angiogenesis is an important factor in determining prostate cancer development and prognosis. Vascular Endothelial Growth Factor (VEGF) is thought to play a primary role in the molecular events that lead to prostate cancer progression, from androgen-dependency to castration-resistance until dissemination to the skeleton. Bevacizumab is a recombinant anti-VEGF monoclonal antibody that has exhibited clinical activity in different cancer types. Areas covered: In this review we summarize the data of clinical trials, investigating the effects of bevacizumab in prostate cancer patients. Until now, the drug has demonstrated anti-tumoral activity although with no improvements in overall survival (OS) and a wide range of alarming side effects in metastatic castration-resistant prostate cancer (mCRPC). Recently, promising results were achieved, using bevacizumab in combination with androgen deprivation therapy (ADT) in patients with recurrent prostate cancer after definitive local therapy. Expert opinion: The suboptimal efficacy of bevacizumab may relate to molecular events triggered during disease progression, such as redundancy of angiogenic factors or the interfering influence of androgens on angiogenic pathways. Further studies, using bevacizumab in combination with ADT and/or inhibitors of other key pathways on the subset of patients with low burden, hormone sensitive prostate cancer, need to be conducted.

Role of chemotherapy in prostate cancer

Chemotherapy in prostate cancer (PCa) has undergone dramatic landscape changes. While earlier studies utilized varying chemotherapy regimens which were found to be largely palliative in nature and hardly resulted in durable or meaningful responses, docetaxel resulted in the first chemotherapy agent that showed improvement in overall survival in metastatic castration-resistant prostate cancer (mCRPC). However, combination chemotherapy or any agents added to docetaxel have failed to yield incremental benefits. The improvement in overall survival as well as secondary endpoints of prostate-specific antigen (PSA) and time to recurrence when using docetaxel in the metastatic hormone-sensitive state has changed the standard of care for treatment of newly diagnosed de novo metastatic PCa. There are also promising results in locally advanced PCa and high-risk PCa in both the neoadjuvant and adjuvant settings. This review summarizes the historical as well as the more contemporary use of chemotherapeutic agents in PCa in varying states and phases of disease.

Radical Prostatectomy for High-risk Localized or Node-Positive Prostate Cancer: Removing the Primary

PURPOSE OF REVIEW

We reviewed the literature to determine what role, if any, radical prostatectomy should play in the treatment of high-risk and/or node-positive prostate cancer.

RECENT FINDINGS

The AUA, NCCN, and EAU all include radical prostatectomy as a treatment option for high-risk prostate cancer based on evidence that has shown improvements in biochemical-free and disease-specific survival. Lymph node-positive patients may also derive benefit from radical prostatectomy with lymph node dissection, however, only retrospective studies with high risk of selection bias have been published to date. High-risk prostate cancer is a heterogeneous disease representing a wide range of disease characteristics. Radical surgery, historically avoided in such patients, may now be considered a valid treatment option for select cases. The adverse effects of surgery using modern techniques lead to similar quality of life outcomes as radiation therapy, and treatment of the primary tumor is likely beneficial when compared to ADT alone.

Neoadjuvant and adjuvant treatment in high-risk prostate cancer

INTRODUCTION

High-risk prostate cancer (HRPCa) represents a heterogeneous disease with potential risk for local and distant progression. In these patients, a multi-modal approach consisting of neoadjuvant and/or adjuvant systemic therapies has been proposed. The aim of this review is to summarize the emerging roles of neoadjuvant and adjuvant therapies in HRPCa patients. Areas covered: This review collects the most relevant phase III randomized controlled trials (RCTs) testing the effect of neoadjuvant and adjuvant systemic therapies in combination with radical prostatectomy (RP) or radiotherapy (RT) for HRPCa patients. Specifically, the review examines the benefit provided by androgen deprivation therapy (ADT), chemotherapy (CHT), and novel antiandrogen agents in this setting. A search of bibliographic databases for peer-reviewed literature was conducted. Expert commentary: Three decades of RCTs demonstrated that adjuvant ADT is fundamental in HRPCa treated with RT. Conversely, ADT and CHT did not improve the survival of HRPCa patients managed with RP. The recent introduction of novel antiandrogen agents combined with an appropriated selection of patients at risk of cancer progression, may ultimately extend the indication of neoadjuvant and adjuvant therapy in surgical- and radio-treated patients.

Role of radical prostatectomy in metastatic prostate cancer: A review

CONTEXT

Recent demonstration of efficacy with the use of chemohormonal therapy for men with metastatic prostate cancer (mPCa) has expanded the therapeutic options for these patients. Furthermore, multimodal therapy to treat systemic disease in the context of locoregional control has gained increasing interest. Concomitantly, the role of radical prostatectomy (RP) in multimodal treatment for locally advanced prostate cancer is expanding. As a result, there is interest in investigating the potential benefit of cytoreductive RP in mPCa.

OBJECTIVE

To review the literature regarding the role of cytoreductive prostatectomy in the setting of mPCa.

EVIDENCE ACQUISITION

MEDLINE and PubMed electronic databases were queried for English language articles related to patients with mPCa who underwent RP from January 1990 to June 2016. Key words used in our search included cytoreductive prostatectomy, radical prostatectomy, and metastatic prostate cancer. Preclinical, retrospective, and prospective studies were included.

EVIDENCE SYNTHESIS

There are no published randomized control trials examining the role of cytoreduction in mPCa. Local symptoms are high in mPCa and often provide a necessity for palliative procedures with the impact on oncologic outcomes being uncertain. Recently, preclinical and retrospective population-based data suggest a benefit from treatment of the primary tumor in metastatic disease. Potential mechanisms mediating this benefit include prevention of symptomatic local progression and modulation of disease biology, resulting in an improvement in progression-free and overall survival. Current literature supports the feasibility of cytoreductive prostatectomy as it is associated with acceptable side effects that are comparable to RP for high-risk localized disease. In aggregate, these data compel prospective evaluation of the hypothesis that cytoreductive prostatectomy improves the outcome of men with mPCa.

CONCLUSIONS

Cytoreductive prostatectomy in mPCa is a feasible procedure that may improve outcomes for men when combined with multimodal management. Preclinical, translational, and retrospective evidence supports local therapy for metastatic disease. However, currently, evidence is limited and is subject to bias. The results of ongoing prospective randomized trials are required before incorporating this therapeutic strategy into clinical practice.

The role of chemotherapy and new targeted agents in the management of primary prostate cancer

While early treatment of primary prostate cancer is very effective, the incidence of primary prostate cancer continues to rise and therefore the detection of men with high-risk non-metastatic prostate cancer and their subsequent management is becoming increasingly important. There continues to be no molecularly-targeted or chemotherapeutic options with proven, statistically significant survival benefit in this setting. However, there are indications that further risk stratification using molecular features could potentially help distinguish indolent from aggressive prostate cancer, ultimately providing biological markers that could guide a more personalised approach to therapy selection.

A Randomized Phase II Trial of Short-Course Androgen Deprivation Therapy With or Without Bevacizumab for Patients With Recurrent Prostate Cancer After Definitive Local Therapy

PURPOSE

Patients with recurrent prostate cancer after local treatment make up a heterogeneous population for whom androgen deprivation therapy (ADT) is the usual treatment. The purpose of this randomized phase II trial was to investigate the efficacy and toxicity of short-course ADT with or without bevacizumab in men with hormone-sensitive prostate cancer.

PATIENTS AND METHODS

Eligible patients had an increasing prostate-specific antigen (PSA) of ≤ 50 ng/mL and PSA doubling time of less than 18 months. Patients had either no metastases or low burden, asymptomatic metastases (lymph nodes < 3 cm and five or fewer bone metastases). Patients were randomly assigned 2:1 to a luteinizing hormone-releasing hormone agonist, bicalutamide and bevacizumab or ADT alone, for 6 months. The primary end point was PSA relapse-free survival (RFS). Relapse was defined as a PSA of more than 0.2 ng/mL for prostatectomy patients or PSA of more than 2.0 ng/mL for primary radiation therapy patients.

RESULTS

Sixty-six patients received ADT + bevacizumab and 36 received ADT alone. Patients receiving ADT + bevacizumab had a statistically significant improvement in RFS compared with patients treated with ADT alone (13.3 months for ADT + bevacizumab v 10.2 months for ADT alone; hazard ratio, 0.47; 95% CI, 0.29 to 0.77; log-rank P = .002). Hypertension was the most common adverse event in patients receiving ADT + bevacizumab (36%).

CONCLUSION

ADT combined with bevacizumab resulted in an improved RFS for patients with hormone-sensitive prostate cancer. Long-term follow-up is needed to determine whether some patients have a durable PSA response and are able to remain off ADT for prolonged periods. Our data provide rationale for combining vascular endothelial growth factor-targeting therapy with ADT in hormone-sensitive prostate cancer.

Neoadjuvant therapy for localized prostate cancer: Examining mechanism of action and efficacy within the tumor

OBJECTIVES

Efforts to improve the clinical outcome for patients with localized high-risk prostate cancer have led to the development of neoadjuvant systemic therapies. We review the different modalities of neoadjuvant therapies for localized prostate cancer and highlight emerging treatment approaches including immunotherapy and targeted therapy.

METHODS

We performed a PubMed search of clinical trials evaluating preoperative systemic therapies for treating high-risk prostate cancer published after 2000, and those studies with the highest clinical relevance to current treatment approaches were selected for review. The database at clinicaltrials.gov was queried for neoadjuvant studies in high-risk prostate cancer, and those evaluating novel targeted therapies and immunotherapies are spotlighted here.

RESULTS

Neoadjuvant chemotherapy has become standard of care for treating some malignancies, including breast and bladder cancers. In prostate cancer, preoperative hormonal therapy or chemotherapy has failed to demonstrate improvements in overall survival. Nevertheless, the emergence of novel treatment modalities such as targeted small molecules and immunotherapy has spawned neoadjuvant clinical trials that provide a unique vantage from which to study mechanism of action and biological potency. Tissue-based biomarkers are being developed to elucidate the biological efficacy of these treatments. With targeted therapy, these can include phospho-proteomic signatures of target pathway activation and deactivation. With immunotherapies, including sipuleucel-T and ipilimumab, recruitment of immune cells to the tumor microenvironment can also be used as robust markers of a biological effect. Such studies can provide insight not only into mechanism of action for these therapies but can also provide paths forward to improving clinical efficacy like with rationally designed combinations and dose selection.

CONCLUSIONS

The use of neoadjuvant androgen-deprivation therapy and chemotherapy either singly or in combination before radical prostatectomy is generally safe and feasible while reducing prostate volume and tumor burden. However, pathologic complete response rates are low and no long-term survival benefit has been observed with the addition of neoadjuvant therapies over surgery alone at present, and therefore preoperative therapy is not the current standard of care in prostate cancer treatment.

Evading anti-angiogenic therapy: resistance to anti-angiogenic therapy in solid tumors

Vascular endothelial growth factor (VEGF) dependent tumor angiogenesis is an essential step for the initiation and promotion of tumor progression. The hypothesis that VEGF-driven tumor angiogenesis is necessary and sufficient for metastatic progression of the tumor, has been the major premise of the use of anti-VEGF therapy for decades. While the success of anti-VEGF therapy in solid tumors has led to the success of knowledge-based-therapies over the past several years, failures of this therapeutic approach due to the development of inherent/acquired resistance has led to the increased understanding of VEGF-independent angiogenesis. Today, tumor-angiogenesis is not a synonymous term to VEGF-dependent function. The extensive study of VEGF-independent angiogenesis has revealed several key factors responsible for this phenomenon including the role of myeloid cells, and the contribution of entirely new phenomenon like vascular mimicry. In this review, we will present the cellular and molecular factors related to the development of anti-angiogenic resistance following anti-VEGF therapy in different solid tumors.

Docetaxel, bevacizumab, and androgen deprivation therapy for biochemical disease recurrence after definitive local therapy for prostate cancer

BACKGROUND

Patients with biochemical disease recurrence (BCR) after definitive treatment for prostate cancer comprise a heterogeneous population for whom standard therapy options are lacking. The purpose of the current trial was to evaluate the feasibility, toxicity, and efficacy of early multimodality systemic therapy in men with BCR.

METHODS

Eligible patients had an increasing prostate-specific antigen (PSA) level, a PSA doubling time ≤10 months, and no evidence of metastases after radical prostatectomy (RP) and/or radiotherapy (RT) for localized disease. Treatment consisted of docetaxel at a dose of 75 mg/m(2) every 3 weeks for 4 cycles, bevacizumab at a dose of 15 mg/kg every 3 weeks for 8 cycles, and androgen deprivation therapy (ADT) for 18 months. The primary endpoint was the percentage of patients who were free from PSA progression 1 year after the completion of therapy.

RESULTS

A total of 41 patients were included in the analysis. At 1 year after the completion of ADT, 45% of patients (13 of 29 patients) and 29% of patients (5 of 17 patients) with a testosterone level ≥100 ng/dL and ≥240 ng/dL, respectively, had a PSA <0.2 ng/mL. The median follow-up was 27.5 months (interquartile range, 21.8-38.1 months). Eight patients (20%) were free from PSA progression, 19 patients (46%) did not reinitiate ADT, and 34 patients (83%) were free from metastasis. Sixteen patients (39%) experienced grade 3 and 5 patients (12%) experienced grade 4 toxicities (toxicity was assessed using the National Cancer Institute Common Terminology Criteria for Adverse Events [version 3.0]).

CONCLUSIONS

Multimodality systemic therapy with docetaxel, bevacizumab, and ADT is feasible and produces PSA responses in men with BCR. Long-term follow-up is needed to determine the percentage of patients with a durable PSA response who are able to avoid having to reinitiate prostate cancer therapy.

Chemotherapy and novel therapeutics before radical prostatectomy for high-risk clinically localized prostate cancer

Although both surgery and radiation are potential curative options for men with clinically localized prostate cancer, a significant proportion of men with high-risk and locally advanced disease will demonstrate biochemical and potentially clinical progression of their disease. Neoadjuvant systemic therapy before radical prostatectomy (RP) is a logical strategy to improve treatment outcomes for men with clinically localized high-risk prostate cancer. Furthermore, delivery of chemotherapy and other systemic agents before RP affords an opportunity to explore the efficacy of these agents with pathologic end points. Neoadjuvant chemotherapy, primarily with docetaxel (with or without androgen deprivation therapy), has demonstrated feasibility and safety in men undergoing RP, but no study to date has established the efficacy of neoadjuvant chemotherapy or neoadjuvant chemohormonal therapies. Other novel agents, such as those targeting the vascular endothelial growth factor receptor, epidermal growth factor receptor, platelet-derived growth factor receptor, clusterin, and immunomodulatory therapeutics, are currently under investigation.

Intense androgen-deprivation therapy with abiraterone acetate plus leuprolide acetate in patients with localized high-risk prostate cancer: results of a randomized phase II neoadjuvant study

PURPOSE

Cure rates for localized high-risk prostate cancers (PCa) and some intermediate-risk PCa are frequently suboptimal with local therapy. Outcomes are improved by concomitant androgen-deprivation therapy (ADT) with radiation therapy, but not by concomitant ADT with surgery. Luteinizing hormone-releasing hormone agonist (LHRHa; leuprolide acetate) does not reduce serum androgens as effectively as abiraterone acetate (AA), a prodrug of abiraterone, a CYP17 inhibitor that lowers serum testosterone (< 1 ng/dL) and improves survival in metastatic PCa. The possibility that greater androgen suppression in patients with localized high-risk PCa will result in improved clinical outcomes makes paramount the reassessment of neoadjuvant ADT with more robust androgen suppression.

PATIENTS AND METHODS

A neoadjuvant randomized phase II trial of LHRHa with AA was conducted in patients with localized high-risk PCa (N = 58). For the first 12 weeks, patients were randomly assigned to LHRHa versus LHRHa plus AA. After a research prostate biopsy, all patients received 12 additional weeks of LHRHa plus AA followed by prostatectomy.

RESULTS

The levels of intraprostatic androgens from 12-week prostate biopsies, including the primary end point (dihydrotestosterone/testosterone), were significantly lower (dehydroepiandrosterone, Δ(4)-androstene-3,17-dione, dihydrotestosterone, all P < .001; testosterone, P < .05) with LHRHa plus AA compared with LHRHa alone. Prostatectomy pathologic staging demonstrated a low incidence of complete responses and minimal residual disease, with residual T3- or lymph node-positive disease in the majority.

CONCLUSION

LHRHa plus AA treatment suppresses tissue androgens more effectively than LHRHa alone. Intensive intratumoral androgen suppression with LHRHa plus AA before prostatectomy for localized high-risk PCa may reduce tumor burden.

Surgical management of prostate cancer

Surgery remains a mainstay in the management of localized prostate cancer. This article addresses surgical aspects germane to the management of men with prostate cancer, including patient selection for surgery, nerve-sparing approaches, minimization of positive surgical margins, and indications for pelvic lymph node dissection. Outcomes for men with high-risk prostate cancer following surgery are reviewed, and the present role of neoadjuvant therapy before radical prostatectomy is discussed. In addition, there is a review of the published literature on surgical ablative therapies for prostate cancer.

[Neoadjuvant before surgery treatments: state of the art in prostate cancer]

GOAL

To study the impact of systemic treatment in neoadjuvant strategy before surgery in prostate cancer.

MATERIALS

Literature reviews with data analysis from PubMed search using the keywords "neoadjuvant", "chemotherapy", "hormonal therapy", "prostate surgery", "radical prostatectomy", but also reports from ASCO and ESMO conferences. The articles on neoadjuvant treatment before radiotherapy were excluded.

RESULTS

First studies with former therapy are more than 15-years-old and with questionable methodology: lack of power to have a clear idea of the impact on survival criteria such as overall survival or relapse-free survival. However, the impact of neoadjuvant hormone therapy on the classic risk factors for relapse (positive margins, intraprostatic disease, positive lymph nodes) was demonstrated by these studies and a Cochrane meta-analysis. The association with hormone therapy seems mandatory in comparison to treatment based solely on chemotherapy and/or targeted therapy. Promising data on the use of new drugs and their combinations arise: abiraterone acetate combined with LHRH analogue showed a fast PSA decrease and higher rates of pathologic complete response. Other results are promising with hormonal blockages at various key points.

CONCLUSION

Studies with 2nd generation anti-androgene agents or enzyme inhibitors seem to show very promising results. To provide answers about the effectiveness of current neoadjuvant strategy in terms of survival, other studies are needed: randomized phase III or phase II exploring predictive biomarkers. The design of such trials requires a multidisciplinary approach with urologists, oncologists, radiologists and methodologists.

The novel toluidine sulphonamide EL102 shows pre-clinical in vitro and in vivo activity against prostate cancer and circumvents MDR1 resistance

Background:

Taxanes are routinely used for the treatment of prostate cancer, however the majority of patients eventually develop resistance. We investigated the potential efficacy of EL102, a novel toluidine sulphonamide, in pre-clinical models of prostate cancer.

Methods:

The effect of EL102 and/or docetaxel on PC-3, DU145, 22Rv1 and CWR22 prostate cancer cells was assessed using cell viability, cell cycle analysis and PARP cleavage assays. Tubulin polymerisation and immunofluorescence assays were used to assess tubulin dynamics. CWR22 xenograft murine model was used to assess effects on tumour proliferation. Multidrug-resistant lung cancer DLKPA was used to assess EL102 in a MDR1-mediated drug resistance background.

Results:

EL102 has in vitro activity against prostate cancer, characterised by accumulation in G2/M, induction of apoptosis, inhibition of Hif1α, and inhibition of tubulin polymerisation and decreased microtubule stability. In vivo, a combination of EL102 and docetaxel exhibits superior tumour inhibition. The DLKP cell line and multidrug-resistant DLKPA variant (which exhibits 205 to 691-fold greater resistance to docetaxel, paclitaxel, vincristine and doxorubicin) are equally sensitive to EL102.

Conclusion:

EL102 shows potential as both a single agent and within combination regimens for the treatment of prostate cancer, particularly in the chemoresistance setting.

Rationale for and review of neoadjuvant therapy prior to radical prostatectomy for patients with high-risk prostate cancer

Despite state of the art local therapy, a significant portion of men with high-risk prostate cancer develop progressive disease. Neoadjuvant systemic therapy prior to radical prostatectomy (RP) is an approach that can potentially maximize survival outcomes in patients with localized disease. This approach is under investigation with a wide array of agents and provides an opportunity to assess pathologic and biologic activity of novel treatments. The aim of this review is to explore the past and present role of neoadjuvant therapy prior to definitive therapy with RP in patients with high-risk localized or locally advanced disease. The results of neoadjuvant androgen-deprivation therapy (ADT), including use of newer agents such as abiraterone, are promising. Neoadjuvant chemotherapy, primarily with docetaxel, with or without ADT has also demonstrated efficacy in men with high-risk disease. Other novel agents targeting the vascular endothelial growth factor receptor (VEGFR), epidermal growth factor receptor (EGFR), platelet-derived growth factor receptor (PDGFR), clusterin, and the immune system are currently under investigation and have led to variable results in early clinical trials. Despite optimistic data, approval of neoadjuvant therapy prior to RP in patients with high-risk prostate cancer will depend on positive results from well designed phase III trials.

Prognostic value of vascular endothelial growth factor expression in patients with prostate cancer: a systematic review with meta-analysis

BACKGROUND

The vascular endothelial growth factor (VEGF) mediates vasculogenesis and angiogenesis through promoting endothelial cell growth, migration and mitosis, and has involvement in cancer pathogenesis, progression and metastasis. However, the prognostic value of VEGF in patients with prostate cancer remains controversial.

OBJECTIVES

The aim of our study was to evaluate the prognostic value of VEGF in prostate cancer, and summarise the results of related research on VEGF.

METHODS

In accordance with an established search strategy, 11 studies with 1,529 patients were included in our meta-analysis. The correlation of VEGF-expression with overall survival and progression-free survival was evaluated by hazard ratio, either given or calculated.

RESULTS

The studies were categorized by introduction of the author, demographic data in each study, prostate cancer-relatived information, VEGF cut-off value, VEGF subtype, methods of hazard ratio (HR) estimation and its 95% confidence interval (CI). High VEGF-expression in prostate cancer is a poor prognostic factor with statistical significance for OS (HR=2.32, 95%CI: 1.40-3.24). However, high VEGF-expression showed no effect on poor PFS (HR=1.30, 95%CI: 0.88-1.72). Using Begg's, Egger's test and funnel plots, we confirmed lack of publication bias in our analysis.

CONCLUSION

VEGF might be regarded as a prognostic maker for prostate cancer, as supported by our meta-analysis. To achieve a more definitive conclusion enabling the clinical use of VEGF in prostate cancer, we need more high-quality interventional original studies following agreed research approaches or standards.

Current role of neoadjuvant and adjuvant systemic therapy for high-risk localized prostate cancer

PURPOSE OF REVIEW

Although most men are diagnosed with readily curable localized prostate cancer, those with high-risk features face a significant mortality risk. Androgen deprivation therapy (ADT) is a standard adjunct to radiotherapy for high-risk prostate cancer, but its role around prostatectomy has not been as clearly defined, and concerns over cardiovascular toxicity have led to decreasing use. The use of chemotherapy for localized disease remains experimental. We review the most recently published trials of neoadjuvant or adjuvant systemic therapy for prostate cancer.

RECENT FINDINGS

The optimal duration of ADT with higher dose modern radiation techniques is under active investigation, but current data support the use of longer duration as standard. Prostate-specific antigen (PSA) and MRI changes may be useful in future studies optimizing duration of neoadjuvant ADT. Two years of combined ADT after prostatectomy is associated with a lower risk of disease recurrence and better prostate cancer specific mortality than predicted. Persistence of intraprostatic androgens during neoadjuvant ADT may contribute to resistance.

SUMMARY

Androgen deprivation added to definitive radiation or surgery improves outcomes for high-risk prostate cancer, although the role of chemotherapy remains undefined. Molecular classification is needed to improve risk stratification.

Analysis of the correlation between endorectal MRI response to neoadjuvant chemotherapy and biochemical recurrence in patients with high-risk localized prostate cancer

BACKGROUND

Intermediate end points are desirable to expedite the integration of neoadjuvant systemic therapy into the treatment strategy for high-risk localized prostate cancer. Endorectal magnetic resonance imaging at 1.5 Tesla (1.5T erMRI) response has been utilized as an end point in neoadjuvant trials but has not been correlated with clinical outcomes.

METHODS

Data were pooled from two trials exploring neoadjuvant chemotherapy in high-risk localized prostate cancer. Trial 1 explored docetaxel for 6 months and Trial 2 explored docetaxel plus bevacizumab for 4.5 months, both before radical prostatectomy. erMRI was done at baseline and end of chemotherapy. 1.5T erMRI response, based upon T2W sequences, was recorded. Multivariable Cox regression was undertaken to evaluate the association between clinical parameters and biochemical recurrence.

RESULTS

There were 53 evaluable patients in the combined analysis: 20 (33%) achieved a PSA response, 16 (27%) achieved an erMRI partial response and 24 (40%) achieved an erMRI minor response. Median follow-up was 4.2 years, and 33 of 53 evaluable (62%) patients developed biochemical recurrence. On multivariable analysis, PSA response did not correlate with biochemical recurrence (hazard ratio=0.58, 95% confidence interval (CI) 0.25-1.33) and paradoxically erMRI response was associated with a significantly shorter time to biochemical recurrence (hazard ratio=2.47, 95% CI 1.00-6.13).

CONCLUSIONS

Response by 1.5T erMRI does not correlate with a decreased likelihood of biochemical recurrence in patients with high-risk localized prostate cancer treated with neoadjuvant docetaxel and may be associated with inferior outcomes. These data do not support the use of 1.5T erMRI response as a primary end point in neoadjuvant chemotherapy trials.

Neoadjuvant Chemotherapy prior to Radical Prostatectomy for Patients with High-Risk Prostate Cancer: A Systematic Review

High-risk prostate cancer represents a pretentious clinical problem since a significant number of its patients will relapse and progress after radical prostatectomy. Neoadjuvant chemotherapy may be valuable since its efficacy in hormone-resistant prostate cancer has been established. In this paper, we report studies of neoadjuvant chemotherapies that have been used in high-risk patients prior to radical prostatectomy. Even though the results regarding the prognostic surrogates are not significant, the effects on clinical and pathological outcomes are promising, while toxicity in most of the studies is in the expected field.

Angiogenesis and anti-angiogenic therapy in prostate cancer

Inhibition of angiogenic pathways has proven an effective strategy for the treatment of several common solid tumors however its role in the management of prostate cancer is yet to be defined. Advances in clinical research have resulted in five new treatments for metastatic prostate cancer in the last two years. The immunotherapy sipuleucel-T, the cytotoxic cabazitaxel, the androgen biosynthesis inhibitor abiraterone acetate, the radioisotope radium-223 and the antiandrogen enzalutamide have all been shown to improve overall survival in randomized phase III studies treatment paradigms are changing rapidly. Angiogenesis is known to play a central role in the progression of advanced prostate cancer however established antiangiogenic therapies including bevacizumab and sunitinib have failed to improve survival in randomized trials to date. Novel treatment combinations and novel agents such as cabozantinib are showing promising early results and it is hoped that further well-designed studies will validate the strong biological hypothesis for the benefit of antiangiogenic therapy to improve outcomes for patients with prostate cancer.

Targeting angiogenesis as a promising modality for the treatment of prostate cancer

Antiangiogenic therapy has been successful for the treatment of solid tumors. Several strategies have been used to target angiogenesis in prostate cancer. These strategies include blocking proangiogenic factors via monoclonal antibodies or small molecule inhibitors targeting downstream signaling effector pathways, or using agents with immune-modulatory effects. This review examines the general concepts of tumor angiogenesis and the key clinical trials that have used these agents and other novel biologics in prostate cancer. Targeting angiogenesis is still a promising treatment strategy in prostate cancer with a rational trial design and combination approach.

Pilot Phase II Trial of Bevacizumab Monotherapy in Nonmetastatic Castrate-Resistant Prostate Cancer

Introduction/Background. Nonmetastatic castrate resistant prostate cancer (CRPC) is a challenging disease state. The objective of this study was to evaluate the efficacy and tolerability of bevacizumab in nonmetastatic CRPC patients. Patients. Patients with prostate cancer who developed PSA recurrence after local therapy were included if they had absence of bone or visceral metastases and PSA progression despite androgen deprivation therapy. Methods. Bevacizumab 10 mg/kg intravenously was administered every 14 days until PSA progression, development of metastasis, or unacceptable toxicity. Results. 15 patients were enrolled and treated with bevacizumab for a median duration of 3.1 months. Median baseline PSA was 27 ng/mL, and seven patients had Gleason Score ≥8. Five patients had declined in PSA during the treatment. Median PSA doubling time was prolonged from 4.7 months pretreatment to 6.5 months. Median time to PSA progression and new metastasis were 2.8 and 7.9 months, respectively. There were three grade 3 adverse events (one proteinuria and two hypertension) and one pulmonary embolism. There was no treatment-related mortality. Conclusion. Bevacizumab therapy had minimal impact on the disease course of nonmetastatic CRPC, and investigation of novel strategies is needed.