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

Amiloride sensitizes prostate cancer cells to the reversible tyrosine kinase inhibitor lapatinib by modulating Erbb3 subcellular localization

Neoadjuvant therapy (NAT) has been studied in clinically localized prostate cancer (PCa) to improve the outcomes from radical prostatectomy (RP) by 'debulking' of high-risk PCa; however, using androgen deprivation therapy (ADT) at this point risks castration resistant PCa (CRPC) clonal proliferation. Our goal is to identify alternative NAT that reduce hormone sensitive PCa (HSPC) without affecting androgen receptor (AR) transcriptional activity. PCa is associated with increased expression and activation of the epidermal growth factor receptor (EGFR) family, including HER2 and ErbB3. The FDA-approved HER2 inhibitor lapatinib has been tested in PCa but was ineffective due to continued activation of ErbB3. We now demonstrate that this is due to ErbB3 being localized to the nucleus in HSPC and thus protected from lapatinib which affect membrane localized HER2/ErbB3 dimers. Here, we show that the well-established, well-tolerated potassium-sparing diuretic amiloride hydrochloride dose dependently prevented ErbB3 nuclear localization via formation of plasma membrane localized HER2/ErbB3 dimers. This in turn allowed lapatinib inactivation of these dimers via inhibition of its target HER2, which dephosphorylated ERK1/2 and inhibited survival. Amiloride combined with lapatinib significantly increased apoptosis at relatively low doses of both drugs but did not affect AR transcriptional activity. Thus, our data indicate that a combination of amiloride and lapatinib could target HSPC tumors without problems associated with using ADT as NAT in HSPC.

Amiloride Sensitizes Prostate Cancer Cells to the Reversible Tyrosine Kinase Inhibitor Lapatinib by Modulating ERBB3 Subcellular Localization

Neoadjuvant therapy (NAT) has been studied in clinically localized prostate cancer (PCa) to improve the outcomes from radical prostatectomy (RP) by 'debulking' of high-risk PCa; however, using androgen deprivation at this point risks castration resistant PCa (CRPC) clonal proliferation with potentially profound side effects such as fatigue, loss of libido, hot flashes, loss of muscle mass, and weight gain. Our goal is to identify alternative NAT that reduce hormone sensitive PCa (HSPC) without affecting androgen receptor (AR) transcriptional activity. PCa is associated with increased expression and activation of the epidermal growth factor receptor (EGFR) family, including HER2 and ErbB3. Dimerization between these receptors is required for activation of downstream targets involved in tumor progression. The FDA-approved HER2 inhibitor lapatinib has been tested in PCa but was ineffective due to continued activation of ErbB3. We now demonstrate that this is due to ErbB3 being localized to the nucleus in HSPC and thus protected from lapatinib which affect membrane localized HER2/ErbB3 dimers. Here, we show that the well-established, well-tolerated diuretic amiloride hydrochloride dose dependently prevented ErbB3 nuclear localization via formation of plasma membrane localized HER2/ErbB3 dimers. This in turn allowed lapatinib inactivation of these dimers via inhibition of its target HER2, which dephosphorylated downstream survival and proliferation regulators AKT and ERK1/2. Amiloride combined with lapatinib significantly increased apoptosis but did not affect AR transcriptional activity. Thus, our data indicate that a combination of amiloride and lapatinib could target HSPC tumors without problems associated with androgen deprivation therapy in localized PCa.

Perioperative Morbidity of Radical Prostatectomy After Intensive Neoadjuvant Androgen Blockade in Men With High-Risk Prostate Cancer: Results of Phase II Trial Compared to a Control Group

INTRODUCTION

Recent studies about intense neoadjuvant therapy followed by Radical Prostatectomy (RP) lack standardized criteria regarding surgical complications and comparison to a group of patients who underwent RP without the use of neoadjuvant therapy. The aim of this study is to describe and compare the perioperative complication rates.

MATERIALS AND METHODS

This was a prospective, single-center phase II trial in patients with high-risk prostate cancer (HRPCa). The control group included HRPCa patients who underwent RP outside the clinical trial during the same study recruitment period. The interventional group was randomized (1:1) to receive neoadjuvant androgen deprivation therapy plus abiraterone with or without apalutamide followed by RP. Complications observed up to 30 days of surgery were classified based on the Clavien-Dindo classification. Uni- and multivariate analyses were carried out to assess predictive factors associated with perioperative complications.

RESULTS

In total, 124 patients with HRPCa were underwent to RP between May 27, 2019 and August 6, 2021, including 61 patients in the intervention group and 63 patients in the control group. The general and major complications in the intervention group reached 29.6% and 6.6%, respectively, and 39.7% and 7.9% in the control group, respectively. There was no significant difference between groups. We observed 4.9% of thromboembolic event in the neoadjuvant group.

CONCLUSIONS

There was no significant increase in morbidity rate in RP after intense neoadjuvant therapy. The association of intense androgen deprivation neoadjuvant therapy with RP and extended pelvic lymphadenectomy may increase the risk of a perioperative thromboembolic events.

Preclinical and Clinical Research Models of Prostate Cancer: A Brief Overview

The incidence and mortality from prostate cancer (PCa) are on the rise which poses a major public health concern worldwide. In this narrative review, we have summarized the characteristics of major in vitro and in vivo PCa models including their utility in developing treatment strategies. Androgens, particularly, testosterone and dihydrotestosterone (DHT) activate the androgen receptor (AR) signaling pathway that facilitates the development and progression of castration resistant PCa. Several enzymes namely, CYP17A1, HSD17B, and SRD5A are essential to furnishing DHT from dehydroepiandrosterone in the classical pathway while DHT is formed from androstanediol in the backdoor pathway. The advancement in delineating the molecular heterogeneity of PCa has been possible through the development of several in vitro and in vivo research models. Generally, tissue culture models are advantageous to understand PCa biology and investigate the efficacy and toxicity of novel agents; nevertheless, animal models are indispensable to studying the PCa etiology and treatment since they can simulate the tumor microenvironment that plays a central role in initiation and progression of the disease. Moreover, the availability of several genetically engineered mouse models has made it possible to study the metastasis process. However, the conventional models are not devoid of limitations. For example, the lack of heterogeneity in tissue culture models and the variation of metastatic characteristics in xenograft models are obviously challenging. Additionally, due to the racial and ethnic disparities in PCa pathophysiology, a new model that can represent PCa encompassing different ethnicities is urgently needed. New models should continue to evolve to address the genetic and molecular complexities as well as to further elucidate the finer details of the steroidogenic pathway associated with PCa.

Neoadjuvant Hormonal Therapy for Prostate Cancer: Morphologic Features and Predictive Parameters of Therapy Response

The primary goals of neoadjuvant hormonal therapy (NHT) in prostate cancer (PCa) are to reduce the size of the tumor, lower positive surgical margin rate, attempt to reach pathologic remission, and improve survival. Although NHT has not been recommended by the National Comprehensive Cancer Network as a primary treatment option for patients with localized PCa, NHT is increasingly used in clinical trials for locally advanced PCa. More importantly, with the development of novel androgen signaling inhibitors, such as abiraterone and enzalutamide, there has been renewed interests in revisiting the role of such treatment in the neoadjuvant setting. Following NHT, the PCa tissues shows characteristic morphologic alterations. Of note, the collapse of malignant glands most likely leads to an artificial increase of Gleason score in the residual disease. Communicating these changes to the clinician in a way that can help assess the tumor's response poses a challenge for pathologists. In addition, little is known of morphologic features and predictive makers both in pretreated and posttreated specimens that can be of value in predicting tumor response to NHT. In the current review, we summarize the morphologic changes associated with neoadjuvant-treated PCa, focusing on the predictive value of pathologic parameters to therapy response. We also describe the evaluation system in the stratification of pathologic response to NHT in PCa management.

NEAR trial: A single-arm phase II trial of neoadjuvant apalutamide monotherapy and radical prostatectomy in intermediate- and high-risk prostate cancer

OBJECTIVE

Treatment efficacy of androgen deprivation therapy with radical prostatectomy for intermediate- to high-risk prostate cancer is less well-studied. The NEAR trial is a single-arm, phase II investigation of neoadjuvant apalutamide monotherapy and radical prostatectomy (RP) in the treatment of D'Amico intermediate- and high-risk prostate cancer (NCT03124433).

MATERIALS AND METHODS

Patients with histologically-proven, D'Amico intermediate- to high-risk prostate adenocarcinoma received apalutamide 240 mg once-daily for 12 weeks followed by RP + /-lymphadenectomy. Primary outcome was pathological complete response (pCR) rate. Secondary outcomes included rate of biochemical response (defined by PSA < 0.03 ng/mL at week 24 from starting apalutamide without subsequent PSA relapse), treatment-related adverse events, and RP complication rates. Correlative biomarker analyses were performed to examine for molecular predictors of treatment responses.

RESULTS

From 2017 to 2019, 30 patients were recruited, of which 20 and 10 were high and intermediate risk, respectively; 25 completed treatment as per-protocol. We did not observe any pCR on trial; median reduction of cancer burden was 41.7% (IQR: 33.3%-60.0%). 18 out of 25 patients were classified as having a biochemical response (4 did not achieve PSA of <0.03 ng/mL at week 24 and 3 developed PSA relapse subsequently). Dry skin (N = 16; 53.3%), fatigue (N = 10; 33.3%) and skin rash (N = 9; 30.0%) were the most common adverse events, and there was no major peri-operative complication. We observed an association between tumours of low androgen receptor activity and PAM50 basal status with biochemical non-responders, albeit these molecular phenotypes were not associated with pathological response.

CONCLUSIONS

A 12-week course of neoadjuvant apalutamide prior to RP did not meet the primary endpoint of pCR in this trial. Tumours with low androgen receptor activity or of the PAM50 basal subtype may have a reduced response to apalutamide.

Biomarkers of Response to Neoadjuvant Androgen Deprivation in Localised Prostate Cancer

Simple Summary

Prostate cancer is the second leading cause of cancer deaths in men. Attempts to improve patient outcomes include trials of neoadjuvant androgen deprivation therapy for patients with high-risk disease. Neoadjuvant treatment refers to androgen deprivation therapy that is administered prior to surgery (or radiation therapy). Patients typically respond well to this treatment regimen, showing a decrease in tumour size, but a significant proportion of patients eventually relapse and progress to metastatic disease. The mechanisms driving this resistance to neoadjuvant treatment are currently unknown. This review explores theories of resistance broadly, and their possible applications in the prostate cancer setting. Additionally, this review draws comparisons between breakthrough resistance and neoadjuvant resistance, and lastly investigates the current biomarkers for treatment sensitivity.

Abstract

Prostate cancer (PCa) is a hormone driven cancer, characterised by defects in androgen receptor signalling which drive the disease process. As such, androgen targeted therapies have been the mainstay for PCa treatment for over 70 years. High-risk PCa presents unique therapeutic challenges, namely in minimising the primary tumour, and eliminating any undetected micro metastases. Trials of neoadjuvant androgen deprivation therapy aim to address these challenges. Patients typically respond well to neoadjuvant treatment, showing regression of the primary tumour and negative surgical margins at the time of resection, however the majority of patients relapse and progress to metastatic disease. The mechanisms affording this resistance are largely unknown. This commentary attempts to explore theories of resistance more broadly, namely, clonal evolution, cancer stem cells, cell persistence, and drug tolerance. Moreover, it aims to explore the application of these theories in the PCa setting. This commentary also highlights the distinction between castration resistant PCa, and neoadjuvant resistant disease, and identifies the markers and characteristics of neoadjuvant resistant disease presented by current literature.

Molecular features of exceptional response to neoadjuvant anti-androgen therapy in high-risk localized prostate cancer

High-risk localized prostate cancer (HRLPC) is associated with a substantial risk of recurrence and disease mortality. Recent clinical trials have shown that intensifying anti-androgen therapies administered before prostatectomy can induce pathologic complete responses or minimal residual disease, called exceptional response, although the molecular determinants of these clinical outcomes are largely unknown. Here, we perform whole-exome and transcriptome sequencing on pre-treatment multi-regional tumor biopsies from exceptional responders (ERs) and non-responders (NRs, pathologic T3 or lymph node-positive disease) to intensive neoadjuvant anti-androgen therapies. Clonal SPOP mutation and SPOPL copy-number loss are exclusively observed in ERs, while clonal TP53 mutation and PTEN copy-number loss are exclusively observed in NRs. Transcriptional programs involving androgen signaling and TGF-β signaling are enriched in ERs and NRs, respectively. These findings may guide prospective validation studies of these molecular features in large HRLPC clinical cohorts treated with neoadjuvant anti-androgens to improve patient stratification.

Feasibility and outcome of radical prostatectomy following inductive neoadjuvant therapy in patients with suspicion of rectal infiltration

OBJECTIVE

To determine the feasibility and outcome of radical prostatectomy (RP) following neoadjuvant therapy (NAT) in patients with initial inoperable, rectum-infiltrating cT4 prostate cancer (PCa).

METHODS

From 01/2018 to 12/2020, 26 patients with clinical (DRE) or radiographical (mpMRI) suspicion of rectum infiltrating PCa at diagnosis and NAT prior to RP were retrospectively identified from our prospective institutional database. Two patients were still inoperable after NAT. Downsizing was administered for at least 20 weeks and RP was performed after excluding ongoing rectal infiltration.

RESULTS

At diagnosis, median PSA was 42.5 ng/ml (IQR: 23.0-66.1). Inductive NAT consisted of androgen deprivation therapy (ADT) in combination with chemotherapy (n = 9) or without chemotherapy (n = 14). Median preoperative PSA was 0.93 ng/ml (IQR: 0.24-0.40). Median time from NAT to RP was 6 months (IQR: 5-7). Two patients were still inoperable after NAT. Of 24 patients undergoing RP, abortion of surgery due to inoperability was observed in 2 patients (8.4%), demonstrating a total failure rate of NAT in 4 out of 26 patients (15.4%). One patient suffered a rectal injury with consecutive colostomy (4.2%). No Clavien-Dindo complication Grade IV or V were observed. Urinary continence was achieved in 16 patients (84.2%). Sufficient erection for sexual intercourse was present in 2 patients (10.5%). All patients received adjuvant ADT with or without radiation therapy. Median PSA at 13 months was 0.08 ng/ml (IQR: 0.01-0.74).

CONCLUSION

RP of initially rectum infiltrating PCa is feasible and safe after inductive NAT, however complications rates tend to be higher compared to standard RP.

Results of a Randomized Phase II Trial of Intense Androgen Deprivation Therapy prior to Radical Prostatectomy in Men with High-Risk Localized Prostate Cancer

PURPOSE

This multicenter randomized phase 2 trial investigates the impact of intense androgen deprivation on radical prostatectomy pathologic response and radiographic and tissue biomarkers in localized prostate cancer (NCT02903368).

MATERIALS AND METHODS

Eligible patients had a Gleason score ≥4+3=7, prostate specific antigen >20 ng/mL or T3 disease and lymph nodes <20 mm. In Part 1, patients were randomized 1:1 to apalutamide, abiraterone acetate, prednisone and leuprolide (AAPL) or abiraterone, prednisone, leuprolide (APL) for 6 cycles (1 cycle=28 days) followed by radical prostatectomy. Surgical specimens underwent central review. The primary end point was the rate of pathologic complete response or minimum residual disease (minimum residual disease, tumor ≤5 mm). Secondary end points included prostate specific antigen response, positive margin rate and safety. Magnetic resonance imaging and tissue biomarkers of pathologic outcomes were explored.

RESULTS

The study enrolled 118 patients at 4 sites. Median age was 61 years and 94% of patients had high-risk disease. The combined pathologic complete response or minimum residual disease rate was 22% in the AAPL arm and 20% in the APL arm (difference: 1.5%; 1-sided 95% CI -11%, 14%; 1-sided p=0.4). No new safety signals were observed. There was low concordance and correlation between posttherapy magnetic resonance imaging assessed and pathologically assessed tumor volume. PTEN-loss, ERG positivity and presence of intraductal carcinoma were associated with extensive residual tumor.

CONCLUSIONS

Intense neoadjuvant hormone therapy in high-risk prostate cancer resulted in favorable pathologic responses (tumor <5 mm) in 21% of patients. Pathologic responses were similar between treatment arms. Part 2 of this study will investigate the impact of adjuvant hormone therapy on biochemical recurrence.

Combination Therapy, a Promising Approach to Enhance the Efficacy of Radionuclide and Targeted Radionuclide Therapy of Prostate and Breast Cancer

In recent years, radionuclide therapy (RT) and targeted radionuclide therapy (TRT) have gained great interest in cancer treatment. This is due to promising results obtained in both preclinical and clinical studies. However, a complete response is achieved in only a small percentage of patients that receive RT or TRT. As a consequence, there have been several strategies to improve RT and TRT outcomes including the combination of these treatments with other well-established anti-cancer therapies, for example, chemotherapy. Combinations of RT and TRT with other therapies with distinct mechanisms of action represent a promising strategy. As for prostate cancer and breast cancer, the two most prevalent cancer types worldwide, several combination-based therapies have been evaluated. In this review, we will provide an overview of the RT and TRT agents currently used or being investigated in combination with hormone therapy, chemotherapy, immunotherapy, and external beam radiation therapy for the treatment of prostate cancer and breast cancer.

Neoadjuvant Approaches Prior To Radical Prostatectomy

Patients with high-risk localized prostate cancer benefit from multimodality therapy of curative intent. Androgen-deprivation therapy (ADT) combined with radiation improves survival in this population. However, prior clinical trials of neoadjuvant ADT and surgery failed to consistently demonstrate a survival advantage. The development of novel, more potent hormonal agents presents an opportunity to revisit the potential for neoadjuvant therapy to improve long-term outcomes for patients with localized prostate cancer. We review recent advances in neoadjuvant approaches for prostate cancer and emerging clinical trials data supporting the use of neoadjuvant therapy prior to radical prostatectomy.

Recent Advances in the Management of High-Risk Localized Prostate Cancer: Local Therapy, Systemic Therapy, and Biomarkers to Guide Treatment Decisions

High-risk prostate cancer accounts for approximately 15% of all prostate cancer diagnoses. Patients with high-risk disease have an increased risk of developing biochemical recurrence, metastases, and death from prostate cancer. As the optimal management of high-risk disease in patients with prostate cancer continues to evolve, the contemporary treatment paradigm is moving toward a multidisciplinary integrated approach of systemic and local therapy for patients with high-risk disease. The strategies for definitive, adjuvant, and salvage local treatment, including radical prostatectomy or radiation therapy, serve as the backbone of therapy for patients with localized disease. Systemic therapy decisions regarding use in combination with surgery, choice of therapy (hormone therapy, chemotherapy), and treatment duration continue to be refined. As more effective hormonal agents populate the treatment landscape for advanced prostate cancer, including abiraterone and next-generation antiandrogens, an opportunity is provided to explore these treatments in patients with localized disease in the hope of improving the long-term outcome for patients. Integration of innovative blood and tissue-based biomarkers to guide therapy selection for patients with high-risk disease is an area of active research. Contemporary studies are using such biomarkers to stratify patients and select therapies. In this review, we summarize contemporary evidence for local treatment strategies, systemic therapy options, and biomarkers in development for the management of high-risk prostate cancer in patients.

Role of surgery in oligometastatic prostate cancer

Androgen deprivation therapy as single modality therapy was the standard management for oligometastatic prostate cancer (PCa). Current paradigm shifts toward a multimodality therapy approach, targeting all sites of disease, including treatment of the primary in the form of radical prostatectomy or radiation therapy. The objective of this article was to reveiw the literature regarding the role of surgery in oligometastatic PCa. PubMed and MEDLINE electronic databases were queried for English language articles from January 1, 1980 to March 31, 2019. Keywords use included oligometastatic PCa, metastatic prostate cancer (mPCa), radical prostatectomy, and cytoreductive prostatectomy. Preclinical, prospective, and retrospective studies were included. There is no published randomized controlled trials, evaluating the role of surgery in mPCa. Preclinical and retrospective data suggest benefit of primary tumor treatment in mPCa. Current literature supports the concept of cytoreductive surgery as it can prevent late symptomatic local progression, has acceptable complications, and may prolong survival in patients with mPCa. Surgery is a feasible procedure in mPCa which may improve outcome in mPCa. However, there is no Level 1 evidence, yet that support the role of surgery in mPCa. The results from well-organized prospective, randomized controlled trials are awaited before performing radical prostatectomy for mPCa in clinical practice.

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.

p53 nuclear accumulation as an early indicator of lethal prostate cancer

Background

After radical prostatectomy (RP) for prostate cancer (PC), p53 alterations predict biochemical relapse (BCR), however, recent evidence suggests that metastatic relapse (MR) not BCR is a surrogate for PC specific mortality (PCSM). This updated analysis of a previously published study investigated the association between p53 aberrations, MR and PCSM in men with localised PC.

Methods

Two hundred and seventy-one men with localised PC treated with RP were included. RP specimens stained for p53 by immunohistochemistry were scored as (a) percentage of p53-positive tumour nuclei; and (b) clustering, where ≥12 p53-positive cells within a ×200 power field was deemed ‘cluster positive’. Associations between p53 status and clinical outcomes (BCR, MR and PCSM) were evaluated.

Results

Increasing percentage of p53-positive nuclei was significantly associated with shorter time to BCR, MR and PCSM (All p < 0.001). Half of the patients were p53 cluster positive. p53 cluster positivity was significantly associated with poorer outcomes at all clinical endpoints (BCR: HR 2.0, 95% CI 1.51–2.65, p < 0.001; MR: HR 4.1, 95% CI 2.02–8.14, p < 0.001; PCSM: HR 12.2, 95% CI 1.6–93; p = 0.016). These associations were independent of other established prognostic variables.

Conclusions

p53 aberrations in radical prostatectomy tissue predict clinically relevant endpoints of MR and PCSM.

Exceptional pathologic complete response achieved with androgen deprivation and docetaxel therapy in Gleason 10 prostate cancer

Pathologic complete response is an exceptionally rare occurrence in prostate cancer, especially in the setting of poorly differentiated cancer, with high risk and poor prognostic features. Patient reviewed and signed an informed consent. The case details were collected.

Patient had PSA of 52.6 ng/dl and Gleason score 5 + 5 = 10 prostate adenocarcinoma with focal signet ring cell pattern. Genomic testing revealed pathogenic p53 and SPOP mutations. The patient received androgen deprivation therapy and six cycles of docetaxel. His PSA declined to undetectable, and radical prostatectomy (RP) showed no evidence of malignancy. The patient has discontinued all therapy and continues in remission 12 months after surgery.

Tumor cell heterogeneity and resistance; report from the 2018 Coffey-Holden Prostate Cancer Academy Meeting

INTRODUCTION

The 2018 Coffey-Holden Prostate Cancer Academy (CHPCA) Meeting, "Tumor Cell Heterogeneity and Resistance," was held in Los Angeles, California from June 21 to 24, 2018.

METHODS

The CHPCA Meeting is a unique, discussion-oriented scientific conference convened annually by the Prostate Cancer Foundation (PCF), which focuses on the most critical topics in need of further study to advance the treatment of lethal prostate cancer. The 6th Annual CHPCA Meeting was attended by 70 investigators and concentrated on prostate cancer heterogeneity and treatment resistance.

RESULTS

The meeting focused on topics including: recognition of tumor heterogeneity, molecular drivers of heterogeneity, the role of the tumor microenvironment, the role of heterogeneity in disease progression, metastasis and treatment resistance, clinical trials designed to target resistance and tumor heterogeneity, and immunotherapeutic approaches to target and overcome tumor heterogeneity.

DISCUSSION

This review article summarizes the presentations and discussions from the 2018 CHPCA Meeting in order to share this knowledge with the scientific community and encourage new studies that will lead to improved treatments and outcomes for men with prostate cancer.

High-throughput screens identify HSP90 inhibitors as potent therapeutics that target inter-related growth and survival pathways in advanced prostate cancer

The development of new treatments for castrate resistant prostate cancer (CRPC) must address such challenges as intrinsic tumor heterogeneity and phenotypic plasticity. Combined PTEN/TP53 alterations represent a major genotype of CRPC (25–30%) and are associated with poor outcomes. Using tumor-derived, castration-resistant Pten/Tp53 null luminal prostate cells for comprehensive, high-throughput, mechanism-based screening, we identified several vulnerabilities among >1900 compounds, including inhibitors of: PI3K/AKT/mTOR, the proteasome, the cell cycle, heat shock proteins, DNA repair, NFκB, MAPK, and epigenetic modifiers. HSP90 inhibitors were one of the most active compound classes in the screen and have clinical potential for use in drug combinations to enhance efficacy and delay the development of resistance. To inform future design of rational drug combinations, we tested ganetespib, a potent second-generation HSP90 inhibitor, as a single agent in multiple CRPC genotypes and phenotypes. Ganetespib decreased growth of endogenous Pten/Tp53 null tumors, confirming therapeutic activity in situ. Fifteen human CRPC LuCaP PDX-derived organoid models were assayed for responses to 110 drugs, and HSP90 inhibitors (ganetespib and onalespib) were among the select group of drugs (<10%) that demonstrated broad activity (>75% of models) at high potency (IC50 <1 µM). Ganetespib inhibits multiple targets, including AR and PI3K pathways, which regulate mutually compensatory growth and survival signals in some forms of CRPC. Combined with castration, ganetespib displayed deeper PDX tumor regressions and delayed castration resistance relative to either monotherapy. In all, comprehensive data from near-patient models presents novel contexts for HSP90 inhibition in multiple CRPC genotypes and phenotypes, expands upon HSP90 inhibitors as simultaneous inhibitors of oncogenic signaling and resistance mechanisms, and suggests utility for combined HSP90/AR inhibition in CRPC.

Neoadjuvant Androgen Deprivation Therapy Prior to Radical Prostatectomy: Recent Trends in Utilization and Association with Postoperative Surgical Margin Status

PURPOSE

In this study, we sought to describe the contemporary trends in utilization of neoadjuvant androgen deprivation therapy (ADT). As a secondary endpoint, we assessed the community-level effect of neoadjuvant ADT on positive surgical margins after radical prostatectomy (RP).

METHODS

Using the National Cancer Database (2004-2014), we identified patients with clinically localized prostate cancer (PCa) [cT1-4N0M0] treated with RP. The estimated annual percentage change (EAPC) mixed linear regression methodology was used for temporal trend analysis of neoadjuvant ADT. Observed differences in baseline characteristics between patients treated with neoadjuvant ADT versus those who were not were then controlled for using an inverse probability of treatment weighting (IPTW) approach. IPTW-adjusted analyses were then performed to examine the odds of positive surgical margins.

RESULTS

Overall, 8184 (2.12%) and 377,843 (97.88%) individuals with PCa were treated with neoadjuvant ADT prior to RP versus RP only, respectively. There was a consistent trend in decreasing use of neoadjuvant ADT over time, with a nadir observed in 2011 [EAPC - 8.08; 95% confidence interval (CI) - 11.7 to - 4.32; p < 0.05]. In IPTW-adjusted analyses, the odds of positive surgical margins were lower in patients receiving neoadjuvant ADT with low-risk [odds ratio (OR) 0.65; 95% CI 0.51-0.84; p < 0.001] and intermediate-risk [OR 0.76; 95% CI 0.69-0.85; p < 0.001] PCa.

CONCLUSIONS

After a period of steady decline, there appears to be a modest trend towards increased utilization of neoadjuvant ADT in more recent years. We found an association between neoadjuvant ADT and decreased odds of positive surgical margins among low- and intermediate-risk patients.

Neoadjuvant-Intensive Androgen Deprivation Therapy Selects for Prostate Tumor Foci with Diverse Subclonal Oncogenic Alterations

Primary prostate cancer can have extensive microheterogeneity, but its contribution to the later emergence of metastatic castration-resistant prostate cancer (mCRPC) remains unclear. In this study, we microdissected residual prostate cancer foci in radical prostatectomies from 18 men treated with neoadjuvant-intensive androgen deprivation therapy (leuprolide, abiraterone acetate, and prednisone) and analyzed them for resistance mechanisms. Transcriptome profiling showed reduced but persistent androgen receptor (AR) activity in residual tumors, with no increase in neuroendocrine differentiation. Proliferation correlated negatively with AR activity but positively with decreased RB1 expression, and whole-exome sequencing (WES) further showed enrichment for RB1 genomic loss. In 15 cases where 2 or 3 tumor foci were microdissected, WES confirmed a common clonal origin but identified multiple oncogenic alterations unique to each focus. These findings show that subclones with oncogenic alterations found in mCRPC are present in primary prostate cancer and are selected for by neoadjuvant-intense androgen deprivation therapy. In particular, this study indicates that subclonal RB1 loss may be more common than previously appreciated in intermediate- to high-risk primary prostate cancer and may be an early event, independent of neuroendocrine differentiation, in the development of mCRPC. Comprehensive molecular analyses of primary prostate cancer may detect aggressive subclones and possibly inform adjuvant strategies to prevent recurrence.Significance: Neoadjuvant androgen deprivation therapy for prostate cancer selects for tumor foci with subclonal genomic alterations, which may comprise the origin of metastatic castration-resistant prostate cancer. Cancer Res; 78(16); 4716-30. ©2018 AACR.

Neoadjuvant degarelix with or without apalutamide followed by radical prostatectomy for intermediate and high-risk prostate cancer: ARNEO, a randomized, double blind, placebo-controlled trial

BACKGROUND

Recent retrospective data suggest that neoadjuvant androgen deprivation therapy can improve the prognosis of high-risk prostate cancer (PCa) patients. Novel androgen receptor pathway inhibitors are nowadays available for treatment of metastatic PCa and these compounds are promising for early stage disease. Apalutamide is a pure androgen antagonist with a very high affinity with the androgen receptor. The combination of apalutamide with degarelix, an LHRH antagonist, could increase the efficacy compared to degarelix alone.

OBJECTIVE

The primary objective is to assess the difference in proportions of minimal residual disease at prostatectomy specimen between apalutamide + degarelix vs placebo + degarelix. Various secondary endpoints are assessed: variations of different biomarkers at the tumour level (tissue microarrays to evaluate DNA-PKs, PARP, AR and splice variants, PSMA, etc.), whole transcriptome sequencing, exome sequencing and clinical (PSA and testosterone kinetics, early biochemical recurrence free survival, quality of life, safety, etc.) and radiological endpoints.

METHODS

ARNEO is a single centre, phase II, randomized, double blind, placebo-controlled trial. The plan is to include at least 42 patients per each of the two study arms. Patients with intermediate/high-risk PCa and who are amenable for radical prostatectomy with pelvic lymph node dissection can be included. After signing an informed consent, every patient will undergo a pelvic 68Ga -PSMA-11 PSMA PET/MR and receive degarelix at standard dosage and start assuming apalutamide/placebo (60 mg 4 tablets/day) for 12 weeks. Within thirty days from the last study medication intake the same imaging will be repeated. Every patient will undergo PSA and testosterone testing the day of randomization, before the first drug intake, and after the last dose. Formalin fixed paraffin embedded tumour samples will be collected and used for transcriptome analysis, exome sequencing and immunohistochemistry.

DISCUSSION

ARNEO will allow us to answer, first, whether the combined treatment can result in an increased proportion of patients with minimal residual disease. Secondly, It will enable the study of the molecular consequences at the level of the tumour. Thirdly, what the consequences are of new generation androgen receptor pathway inhibitors on 68Ga -PSMA-11 PET/MR. Finally, various clinical, safety and quality of life data will be collected.

TRIAL REGISTRATION

EUDRaCT number: 2016-002854-19 (authorization date 3rd August 2017). clinicalTrial.gov: NCT03080116 .

Post prostatectomy outcomes of patients with high-risk prostate cancer treated with neoadjuvant androgen blockade

BACKGROUND

Patients with high-risk prostate cancer have an increased likelihood of experiencing a relapse following radical prostatectomy (RP). We previously conducted three neoadjuvant androgen-deprivation therapy (ADT) trials prior to RP in unfavorable intermediate and high-risk disease.

METHODS

In this analysis, we report on the post-RP outcomes of a subset of patients enrolled on these studies. We conducted a pooled analysis of patients with available follow-up data treated on three neoadjuvant trials at three institutions. All patients received intense ADT prior to RP. The primary endpoint was time to biochemical recurrence (BCR). BCR was defined as a PSA ≥ 0.2 ng/mL or treatment with radiation or androgen-deprivation therapy for a rising PSA < 0.2 ng/mL.

RESULTS

Overall, 72 patients were included of whom the majority had a Gleason score ≥ 8 (n = 46, 63.9%). Following neoadjuvant therapy, 55.7% of patients (n = 39/70) had pT3 disease, 40% (n = 28) had seminal vesicle invasion, 12.9% (n = 9) had positive margins, and 11.4% (n = 8) had lymph node involvement. Overall, 11 (15.7%) had tumor measuring ≤ 0.5 cm, which included four patients (5.7%) with a pathologic complete response and seven (10.0%) with residual tumor measuring 0.1-0.5 cm. Compared to pretreatment clinical staging, 10 patients (14.3%) had pathologic T downstaging at RP. The median follow-up was 3.4 years. Overall, the 3-year BCR-free rate was 70% (95% CI 57%, 90%). Of the 15 patients with either residual tumor ≤ 0.5 cm or pathologic T downstaging, no patient experienced a recurrence.

CONCLUSION

In this exploratory pooled clinical trials analysis, we highlight that neoadjuvant therapy prior to RP in unfavorable intermediate and high-risk patients may potentially have a positive impact on recurrence rates. Larger studies with longer follow-up periods are warranted to evaluate the impact of neoadjuvant hormone therapy on pathologic and long-term outcomes.

Carbon nanomaterials sensitize prostate cancer cells to docetaxel and mitomycin C via induction of apoptosis and inhibition of proliferation

We have previously shown that carbon nanofibers (CNFs) and carbon nanotubes (CNTs) can sensitize prostate cancer (PCa) cells to platinum-based chemotherapeutics. In order to further verify this concept and to avoid a bias, the present study investigates the chemosensitizing potential of CNFs and CNTs to the conventional chemotherapeutics docetaxel (DTX) and mitomycin C (MMC), which have different molecular structures and mechanisms of action than platinum-based chemotherapeutics. DU-145 PCa cells were treated with DTX and MMC alone or in combination with the carbon nanomaterials. The impact of the monotreatments and the combinatory treatments on cellular function was then systematically analyzed by using different experimental approaches (viability, short-term and long-term proliferation, cell death rate). DTX and MMC alone reduced the viability of PCa cells to 94% and 68%, respectively, whereas a combined treatment with CNFs led to less than 30% remaining viable cells. Up to 17- and 7-fold higher DTX and MMC concentrations were needed in order to evoke a similar inhibition of viability as mediated by the combinatory treatments. In contrast, the dose of platinum-based chemotherapeutics could only be reduced by up to 3-fold by combination with carbon nanomaterials. Furthermore, combinatory treatments with CNFs led mostly to an additive inhibition of short- and long-term proliferation compared to the individual treatments. Also, higher cell death rates were observed in combinatory treatments than in monotreatments, e.g., a combination of MMC and CNFs more than doubled the cell death rate mediated by apoptosis. Combinations with CNTs showed a similar, but less pronounced impact on cellular functions. In summary, carbon nanomaterials in combination with DTX and MMC evoked additive to partly synergistic anti-tumor effects. CNFs and CNTs possess the ability to sensitize cancer cells to a wide range of structurally diverse chemotherapeutics and thus represent an interesting option for the development of multimodal cancer therapies. Co-administration of chemotherapeutics with carbon nanomaterials could result in a reduction of the chemotherapeutic dosage and thus limit systemic side effects.

[Multimodal therapy of locally advanced prostate cancer]

Locally advanced prostate cancer (LAPCA) comprises about 5-10 % of all newly diagnosed prostate cancers and is associated with the highest prostate cancer specific mortality (approximately 8-20 %). LAPCA is defined by the presence of extraprostatic extension, seminal vesicle invasion, and bladder neck infiltration of pelvic lymph node metastases. It is evident that prognosis can only be improved by interdisciplinary multimodality treatment strategies. Adequate local staging by multiparametric MRI is one of the cornerstones for an individualized, risk-adapted treatment approach. This might consist of extended radical prostatectomy with an extended pelvic lymphadenectomy or intensity-modulated radiation therapy with androgen deprivation as the primary local therapeutic approach. Both treatment strategies may be combined with neoadjuvant or adjuvant radiation therapy or salvage surgery. Combination with neoadjuvant or adjuvant chemotherapy and new androgen receptor pathway inhibitors might also be possible. This article summarizes the current treatment strategies for LAPCA.

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 Novel System for Estimating Residual Disease and Pathologic Response to Neoadjuvant Treatment of Prostate Cancer

BACKGROUND

Pathologic variables that characterize response of prostate carcinoma to current neoadjuvant therapy have not been characterized in detail. This study reports (i) the histological features of prostate cancer treated with abiraterone and enzalutamide and inter-pathologist variance in identifying these features, and (ii) the effect of the novel androgen deprivation agents on residual cancer volume.

METHODS

We reviewed sections of prostatectomies from 37 patients treated with neoadjuvant agents and 22 untreated patients, tabulated the frequency of nine features of cancer (intact cancer glands, isolated cancer cells, poorly formed glands, cribriform architecture, clear spaces, intraductal carcinoma, solid sheets of cancer cells, prominent nucleoli, and previously described ABC grouping) and two features of benign glands (prominent basal cells and coalescent corpora amylacea). We used several methods, including a novel metric (visual grid system), to estimate residual tumor volume.

RESULTS

The most highly reproducible features were ABC grouping (κ = 0.56-0.7), presence of intraductal carcinoma (κ = 0.34-0.72), cribriform architecture (κ = 0.42-0.68), solid sheets of tumor cells (κ = 0.44-0.56), and coalescent corpora amylacea (κ = 0.4-0.54). Among poorly reproducible features were prominent nucleoli (κ = 0.03-0.11), clear spaces (κ = 0.05-0.07), and poorly formed cancer glands (κ = 0.02-0.1). Determination of tumor mass was excellent regardless of the method used-maximum tumor size (κ = 0.9-0.94), tumor area (κ = 0.94-0.96), and grid-based tumor cellularity (κ = 0.9).

CONCLUSIONS

We propose using a set of parameters including maximum tumor size, tumor area/volume, cellularity, volume, and ABC grouping for evaluating radical prostatectomies post-neoadjuvant therapy. Prostate 76:1285-1292, 2016. © 2016 Wiley Periodicals, Inc.

Prostate Stem Cell Antigen Expression in Radical Prostatectomy Specimens Predicts Early Biochemical Recurrence in Patients with High Risk Prostate Cancer Receiving Neoadjuvant Hormonal Therapy

We aimed to identify tissue biomarkers that predict early biochemical recurrence (BCR) in patients with high-risk prostate cancer (PC), toward the goal of increasing the benefits of neoadjuvant hormonal therapy (NHT). In 2005–2012, prostatectomy specimens were collected from 134 PC patients who had received NHT and radical prostatectomy. The expression of 13 tissue biomarkers was assessed in the specimens via immunohistochemistry. Time to BCR and factors predictive of BCR were determined by using the Cox proportional hazards model. During the follow-up period (median, 57.5 months), 67 (50.0%) patients experienced BCR. Four (3.0%) patients were tumor-free in the final pathology assessment, and 101 (75.4%) had negative resection margins. Prostate stem cell antigen (PSCA) was the only significant prognostic tissue biomarker of BCR [hazard ratio (HR), 2.58; 95% confidence interval (CI), 1.06–6.27; p = 0.037] in a multivariable analysis adjusted by the clinicopathological variables that also significantly predicted BCR; these were seminal vesicle invasion (HR, 2.39; 95% CI, 1.32–4.34), initial prostate serum antigen level (HR 1.01; 95% CI, 1.001–1.020), prostate size (HR, 0.93; 95% CI, 0.90–0.97), and the Gleason score of preoperative biopsies (HR, 1.34; 95% CI, 1.01–1.79). We suggest that PSCA is a useful tissue marker for predicting BCR in patients with high risk PC receiving NHT and radical prostatectomy.

Proteomics of vitreous in neovascular age-related macular degeneration

Neovascular age-related macular degeneration (nAMD) has been described as a predominantly inflammatory and proangiogenic retino-choroidal disease. Vitreous humor (VH) is the adjacent and accessible compartment which, due to the vicinity to the retina, might best represent changes of protein-based mediators of nAMD. The aim of this clinical-experimental study was to analyze the nAMD associated VH proteome of previously untreated patients whilst taking different groups of nAMD into account, based on their clinical presentation (clinical diagnosis groups). Electrophoresis coupled online to mass spectrometry (CE-MS) as well as liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) were used to analyze VH of 108 nAMD patients and 24 controls with idiopathic floaters. A total of 101 different proteins with at least two unique peptides could be identified. Using a stringent statistical analysis with implementation of the closed test principle, we were able to identify four proteins that may be involved in the pathophysiology of nAMD: Clusterin, opticin, pigment epithelium-derived factor and prostaglandin-H2 d-isomerase. Using independent samples, ROC-Area under the curve was determined proving the validity of the results: Clusterin 0.747, opticin 0.656, pigment epithelium-derived factor 0.514, prostaglandin-H2 d-isomerase 0.712. In addition, validation through ELISA measurements was performed. The identified proteins may serve as potential biomarkers or even targets of therapy for nAMD.

The biology and treatment of oligometastatic cancer

Clinical reports of limited and treatable cancer metastases, a disease state that exists in a transitional zone between localized and widespread systemic disease, were noted on occasion historically and are now termed oligometastasis. The ramification of a diagnosis of oligometastasis is a change in treatment paradigm, i.e. if the primary cancer site (if still present) is controlled, or resected, and the metastatic sites are ablated (surgically or with radiation), a prolonged disease-free interval, and perhaps even cure, may be achieved. Contemporary molecular diagnostics are edging closer to being able to determine where an individual metastatic deposit is within the continuum of malignancy. Preclinical models are on the outset of laying the groundwork for understanding the oligometastatic state. Meanwhile, in the clinic, patients are increasingly being designated as having oligometastatic disease and being treated owing to improved diagnostic imaging, novel treatment options with the potential to provide either direct or bridging therapy, and progressively broad definitions of oligometastasis.

Advances in systemic therapies for metastatic castration-resistant prostate cancer

ABSTRACT 

The landscape of treatment for metastatic castration-resistant prostate cancer has rapidly evolved during the last 5 years alone. In this review, standard therapies as well as recent advances in the systemic treatment for prostate cancer are explored. Pivotal trial data are summarized with emphasis on indications for various anti-androgen drugs, androgen-biosynthesis inhibitors, chemotherapy, immunotherapy and bone-targeted agents. The clinical, biochemical and radiographic outcomes for men with metastatic castration-resistant prostate cancer are improving with the establishment of several promising novel agents.

Personalizing prostate cancer therapy: the way forward

Advances in genomic sequencing and molecular characterization are improving our understanding of the biology of prostate cancer and challenging us to translate emerging data into meaningful clinical outcomes. Several recently approved treatments for advanced prostate cancer extend survival; however, these therapies are not personalized based on predictive biomarkers. Innovative strategies for early phase drug testing that harness our growing knowledge of important prognostic markers and emerging predictive biomarkers are needed. In this review we discuss new strategies to assess drug response in early phase clinical trial testing.