ODM-201: a new-generation androgen receptor inhibitor in castration-resistant prostate cancer

Therapy resistance in prostate cancer: mechanism, signaling and reversal strategies

Prostate cancer (PC) depicts a major health challenge all over the globe due to its complexities in the treatment and diverse clinical trajectories. Even in the advances in the modern treatment strategies, the spectrum of resistance to the therapies continues to be a significant challenge. This review comprehensively examines the underlying mechanisms of the therapy resistance occurred in PC, focusing on both the tumor microenvironment and the signaling pathways implicated in the resistance. Tumor microenvironment comprises of stromal and epithelial cells, which influences tumor growth, response to therapy and progression. Mechanisms such as microenvironmental epithelial-mesenchymal transition (EMT), anoikis suppression and stimulation of angiogenesis results in therapy resistance. Moreover, dysregulation of signaling pathways including androgen receptor (AR), mammalian target of rapamycin/phosphoinositide 3 kinase/AKT (mTOR/PI3K/AKT), DNA damage repair and Janus kinase/signal transducers and activators of transcription (JAK/STAT) pathways drive therapy resistance by promoting tumor survival and proliferation. Understanding these molecular pathways is important for developing targeted therapeutic interventions which overcomes resistance. In conclusion, a complete grasp of mechanisms and pathways underlying medication resistance in PC is important for the development of individualized treatment plans and enhancements of clinical outcomes. By studying and understanding the complex mechanisms of signaling pathways and microenvironmental factors contributing to therapy resistance, this study focuses and aims to guide the development of innovative therapeutic approaches to effectively overcome the PC progression and improve the survival rate of patients.

Synergistic Strategies for Castration-Resistant Prostate Cancer: Targeting AR-V7, Exploring Natural Compounds, and Optimizing FDA-Approved Therapies

Castration-resistant prostate cancer (CRPC) remains a significant therapeutic challenge due to its resistance to standard androgen deprivation therapy (ADT). The emergence of androgen receptor splice variant 7 (AR-V7) has been implicated in CRPC progression, contributing to treatment resistance. Current treatments, including first-generation chemotherapy, androgen receptor blockers, radiation therapy, immune therapy, and PARP inhibitors, often come with substantial side effects and limited efficacy. Natural compounds, particularly those derived from herbal medicine, have garnered increasing interest as adjunctive therapeutic agents against CRPC. This review explores the role of AR-V7 in CRPC and highlights the promising benefits of natural compounds as complementary treatments to conventional drugs in reducing CRPC and overcoming therapeutic resistance. We delve into the mechanisms of action underlying the anti-CRPC effects of natural compounds, showcasing their potential to enhance therapeutic outcomes while mitigating the side effects associated with conventional therapies. The exploration of natural compounds offers promising avenues for developing novel treatment strategies that enhance therapeutic outcomes and reduce the adverse effects of conventional CRPC therapies. These compounds provide a safer, more effective approach to managing CRPC, representing a significant advancement in improving patient care.

A practical guide for the use of apalutamide for non-metastatic castration-resistant prostate cancer in Australia

Studies of patients with castrate-resistant prostate cancer at high risk of developing overt metastases but with no current evidence of evaluable disease on computed tomography or bone scan non-metastatic castrate-resistant prostrate cancer have demonstrated increased metastasis-free survival and overall survival following treatment with the next-generation oral anti-androgen apalutamide (in addition to therapies that aim to lower testosterone to castrate levels) or luteinizing hormone-releasing hormone antagonist or surgical castration. Patients receiving apalutamide can be managed by medical oncologists, radiation oncologists, or urologists, preferably as part of a multidisciplinary team. However, the importance of additional safety monitoring for significant adverse effects and drug interactions should not be underestimated. The toxicities of apalutamide are manageable with experience and should be managed proactively to minimize their impact on patients. Monitoring of patients for apalutamide-specific toxicities, including skin rash, hypothyroidism, and QT prolongation should be carried out regularly, particularly in the first few months following initiation. Monitoring should continue alongside monitoring for toxicities of androgen deprivation, including cardiovascular risk, hot flashes, weight gain, bone health, muscle wasting, and diabetic risk. This review is a practical guide to the use of apalutamide describing the management of patients including dosing and administration, toxicities, potential drug interactions, and safety monitoring requirements.

New-generation androgen receptor signaling inhibitors (ARSIs) in metastatic hormone-sensitive prostate cancer (mHSPC): pharmacokinetics, drug-drug interactions (DDIs), and clinical impact

INTRODUCTION

The therapeutic scenario of metastatic hormone-sensitive prostate cancer (mHSPC) has dramatically changed in recent years, with the approval of new-generation Androgen Receptor Signaling Inhibitors (ARSIs), in combination with the androgen deprivation therapy (ADT), which was the previous standard of care. Despite showing a similar clinical efficacy, ARSIs, all of which are administered orally, are different in terms of pharmacokinetic and drug-drug interactions (DDIs).

AREAS COVERED

This review covers the main pharmacokinetic characteristics of ARSIs that have been approved for the first-line therapy of mHSPC patients, underlying the differences among these molecules and focusing on the known or possible interactions with other drugs. Full-text articles and abstracts were searched in PubMed.

EXPERT OPINION

Since prostate cancer occurs mainly in older age, comorbidities and the consequent polypharmacy increase the DDI risk in mHSPC patients who are candidates for ARSI. Waiting for new therapeutic options, in the absence of direct comparisons, pharmacokinetic knowledge is essential to guide clinicians in prescribing ARSI in this setting.

Structure-Activity Relationship (SAR) Studies of Novel Monovalent AR/AR-V7 Dual Degraders with Potent Efficacy against Advanced Prostate Cancer

Androgen receptor (AR) has been extensively established as a potential therapeutic target for nearly all stages of prostate cancer (PCa). However, acquired resistance to AR-targeted drugs inevitably develops and severely limits their clinical efficacy. Particularly, there currently exists no efficient treatment for patients expressing the constitutively active AR splice variants, such as AR-V7. Herein, we report the structure-activity relationship studies of 55 N-heterocycle-substituted hydantoins, which identified the structural motifs required for AR/AR-V7 degradation. Among them, the most potent compound 27c exhibited selective AR/AR-V7 degradation over other hormone receptors and excellent antiproliferative activities in LNCaP and 22RV1 cells. RNA sequence analysis confirmed that 27c effectively suppressed transcriptional activity of the AR signaling pathway. Importantly, 27c demonstrated potent antitumor efficacy in an enzalutamide-resistant 22RV1 xenograft model. These results highlight the potential of 27c as a promising dual AR/AR-V7 degrader for overcoming drug resistance in advanced PCa expressing AR splice variants.

Structural Development of Androgen Receptor Antagonists Using Phenylferrocene Framework as a Hydrophobic Pharmacophore

We previously identified nitrophenylferrocenes and cyanophenylferrocenes as promising lead structures of novel androgen receptor (AR) antagonists, based on the structural similarity between ferrocene and the steroidal skeleton. In the present research, we explored the structure-activity relationship (SAR) of phenylferrocene derivatives. Introduction of a hydrophobic substituent such as a chlorine atom at the 2-position or 3-position of phenylferrocene derivatives significantly increased the antagonistic activity toward wild-type AR, and among the synthesized compounds, 3-chloro-4-cyanophenylferrocene (29) exhibited the most potent anti-proliferative activity toward the androgen-dependent growth of SC-3 cells expressing wild-type AR (IC50 14 nM). Like conventional antiandrogens such as hydroxyflutamide, the major active metabolite of flutamide, compound 29 exhibited agonistic activity toward T877A-AR, a mutant AR expressed in human prostate cancer cell line LNCaP. Notably, however, the 2-chloro isomer 27 showed potent antagonistic activity toward wild-type AR (IC50 49 nM) and also exhibited antagonistic activity toward T877A-AR. Our SAR data should prove helpful for the development of new-generation AR antagonists based on phenylferrocene as candidate agents to treat drug-resistant prostate cancer.

Utility of green chemistry for sustainable fluorescence derivatization approach for spectrofluorimetric quantification of Darolutamide as antineoplastic drug in pharmaceutical formulation and spiked human plasma

Darolutamide is an oral nonsteroidal androgen receptor antagonist used to delay the process of prostate cancer to metastatic disease and to increase the quality of life for people with advanced prostate cancer. Here, a second spectrofluorimetric method was advanced for quantifying Darolutamide in pharmaceutical formulation and spiked human plasma. This method depends on the fluorescence derivatization of Darolutamide with 4-chloro-7-nitrobenzo-2-oxa-1,3-diazole (NBD-Cl) at 75°C in a (pH 9) of borate buffer to produce a fluorescent derivative that can be detected at 520 nm after excitation at 460 nm. The method has been validated using ICH criteria, and it demonstrated linearity in the range 5-200 ng ml-1 . The limit of detection (LOD) and limit of quantitation (LOQ) were 1.15 and 3.84 nm, respectively. The proposed method was applied precisely and accurately for quantifying Darolutamide within the pharmaceutical formulation and spiking human plasma without any interferences. Moreover, the method's sustainability was evaluated and compared with the published method using two greenness assessment tools termed analytical eco-scale and Analytical GREEnness (AGREE). These findings suggest that the method is more sustainable than the published method.

Synthesis and application of clinically approved small-molecule drugs targeting androgen receptor

Androgen receptor (AR) plays a crucial role in various physiological processes. Dysregulation of AR signaling has been implicated in several diseases, such as prostate cancer and androgenetic alopecia. Therefore, the development of drugs that specifically target AR has gained significant attention in the field of drug discovery. This review provides an overview of the synthetic routes of clinically approved small molecule drugs targeting AR and discusses the clinical applications of these drugs in the treatment of AR-related diseases. The review also highlights the challenges and future perspectives in this field, including the need for improved drug design and the exploration of novel therapeutic targets. Through an integrated analysis of the therapeutic applications, synthetic methodologies, and mechanisms of action associated with these approved drugs, this review facilitates a holistic understanding of the versatile roles and therapeutic potential of AR-targeted interventions. Overall, this comprehensive review serves as a valuable resource for medicinal chemists interested in the development of small-molecule drugs targeting AR.

Synthesis and clinical application of small-molecule drugs approved to treat prostatic cancer

Prostate cancer is a prevalent form of cancer that primarily affects men, with a high incidence and mortality rate. It is the second most common cancer among males, following lung cancer. Typically occurring in individuals aged 50 and above, this malignant tumor originates from abnormal cells in the prostate tissue. If left untreated, it can spread to nearby tissues, lymph nodes, and even bones. Current treatment methods include surgery, radiotherapy, and chemotherapy. However, these treatments have certain limitations and side effects. Therefore, researching and developing new small-molecule drugs to treat prostate cancer is of great significance. In recent years, many small-molecule drugs have been proven to have therapeutic effects on prostate cancer. The purpose of this review is to give a comprehensive look at the clinical uses and synthetic methods of various significant small-molecule drugs that have been approved to treat prostate cancer, to facilitate the development of more powerful and innovative drugs for the effective control of prostate cancer.

Updates in the Treatment of Non-Metastatic Castrate-Resistant Prostate Cancer: The Benefit of Second-Generation Androgen Receptor Antagonists

OBJECTIVE

To review pharmacology, efficacy, safety, and considerations for use, of second-generation androgen receptor (AR) antagonists in treatment of nonmetastatic castrate-resistant prostate cancer (M0CRPC).

DATA SOURCES

Conducted search in PubMed and Google scholar (January, 1, 2002-December 31, 2022), using relevant terms.

STUDY SELECTION AND DATA EXTRACTION

Relevant English-language studies, conducted in humans evaluating second-generation AR antagonists for M0CRPC, and additional articles and package inserts were considered.

DATA SYNTHESIS

Apalutamide, darolutamide, and enzalutamide are effective in delaying the time to development of metastatic prostate cancer in men with M0CRPC with a rapid prostate-specific antigen (PSA) doubling time (<10 months). No head-to-head, randomized, clinical trials have been conducted. The most common adverse effects include fatigue and hypertension, and quality of life is maintained in most patients. Cost is similar among the agents (~$15,000/month). Drug-drug interactions vary among these agents and should be considered, when selecting therapy as well as likely adherence. Darolutamide is administered twice daily with the others once daily.

RELEVANCE TO PATIENT CARE AND CLINICAL PRACTICE

Second-generation AR antagonists are effective in reducing time to development of metastatic disease and prolonging overall survival in patients with M0CRPC and a PSA doubling time of <10 months. Recent imaging advances may alter how we evaluate outcomes.

CONCLUSIONS

Second-generation AR antagonists improve disease control and overall survival. Generally, they are well tolerated and QOL is maintained. Selection of the best agent is based on the adverse effect profile, potential for drug- and disease-interactions, administration, cost, and patient preference.

Genomic Profiling of Metastatic Castration-Resistant Prostate Cancer Samples Resistant to Androgen Receptor Pathway Inhibitors

PURPOSE

The androgen receptor axis inhibitors (ARPI; e.g., enzalutamide, abiraterone acetate) are administered in daily practice for men with metastatic castration-resistant prostate cancer (mCRPC). However, not all patients respond, and mechanisms of both primary and acquired resistance remain largely unknown.

EXPERIMENTAL DESIGN

In the prospective trial MATCH-R (NCT02517892), 59 patients with mCRPC underwent whole-exome sequencing (WES) and/or RNA sequencing (RNA-seq) of samples collected before starting ARPI. Also, 18 patients with mCRPC underwent biopsy at time of resistance. The objectives were to identify genomic alterations associated with resistance to ARPIs as well as to describe clonal evolution. Associations of genomic and transcriptomic alterations with primary resistance were determined using Wilcoxon and Fisher exact tests.

RESULTS

WES analysis indicated that no single-gene genomic alterations were strongly associated with primary resistance. RNA-seq analysis showed that androgen receptor (AR) gene alterations and expression levels were similar between responders and nonresponders. RNA-based pathway analysis found that patients with primary resistance had a higher Hedgehog pathway score, a lower AR pathway score and a lower NOTCH pathway score than patients with a response. Subclonal evolution and acquisition of new alterations in AR-related genes or neuroendocrine differentiation are associated with acquired resistance. ARPIs do not induce significant changes in the tumor transcriptome of most patients; however, programs associated with cell proliferation are enriched in resistant samples.

CONCLUSIONS

Low AR activity, activation of stemness programs, and Hedgehog pathway were associated with primary ARPIs' resistance, whereas most acquired resistance was associated with subclonal evolution, AR-related events, and neuroendocrine differentiation. See related commentary by Slovin, p. 4323.

Darolutamide for non-metastatic castration-resistant prostate cancer: Efficacy, safety, and clinical perspectives of use

Darolutamide, a second-generation androgen receptor inhibitor (SGARI), has been shown to increase metastasis-free survival and overall survival among men with non-metastatic castration-resistant prostate cancer (nmCRPC). Its unique chemical structure potentially provides efficacy and safety advantages over the SGARIs apalutamide and enzalutamide, which are also indicated for nmCRPC. Despite a lack of direct comparisons, the SGARIs appear to have similar efficacy, safety, and quality of life (QoL) results. Indirect evidence suggests that darolutamide is preferred for its good adverse event profile, an attribute valued by physicians, patients, and their caregivers for maintaining QoL. Darolutamide and others in its class are costly; access may be a challenge for many patients and may lead to modifications to guideline-recommended regimens.

Safe and Efficient Continuous-Flow Synthesis and Batchwise Hydrolysis of Ethyl 5-Acetyl-1H-pyrazole-3-carboxylate: A Key Synthon of Darolutamide

A safe and metal-free process using ethyl glycinate hydrochloride as the starting material has been developed for the preparation of ethyl 5-acetyl-1H-pyrazole-3-carboxylate, a key intermediate for the synthesis of potential blockbuster drug substance darolutamide. In the key step, the toxic and explosive intermediate, ethyl diazoacetate was generated and used in situ. Reaction parameters were optimized for both the batchwise and the continuous-flow variant of the synthesis. In the next step, alkaline hydrolysis of the ester led to 5-acetyl-1H-pyrazole-3-carboxylic acid, which can not only be used as a darolutamide intermediate, but it can also be considered as a valuable building block for other types of organic and medicinal chemistry transformations.

Racial Disparity in Quadruple Negative Breast Cancer: Aggressive Biology and Potential Therapeutic Targeting and Prevention

Simple Summary

Quadruple negative breast cancer (QNBC), a subgroup of triple negative BC, has emerged as a highly aggressive BC subtype that disproportionately afflicts and impacts Black/African-American (AA) women. In this article, we review molecular distinctions in Black/AA and White/European-American (EA) QNBC biology as well as address potential non-genetic risk factors that could be underlying this racially disparate burden. We aim to provide deeper insight and provide a framework for novel discovery of actionable therapeutic targets and identify lifestyle changes to improve outcomes for Black/AA QNBC patients.

Abstract

Black/African-American (AA) women, relative to their White/European-American (EA) counterparts, experience disproportionately high breast cancer mortality. Central to this survival disparity, Black/AA women have an unequal burden of aggressive breast cancer subtypes, such as triple-negative breast cancer (ER/PR-, HER2-wild type; TNBC). While TNBC has been well characterized, recent studies have identified a highly aggressive androgen receptor (AR)-negative subtype of TNBC, quadruple-negative breast cancer (ER/PR-, HER2-wildtype, AR-; QNBC). Similar to TNBC, QNBC disproportionately impacts Black/AA women and likely plays an important role in the breast cancer survival disparities experienced by Black/AA women. Here, we discuss the racial disparities of QNBC and molecular signaling pathways that may contribute to the aggressive biology of QNBC in Black/AA women. Our immediate goal is to spotlight potential prevention and therapeutic targets for Black/AA QNBC; ultimately our goal is to provide greater insight into reducing the breast cancer survival burden experienced by Black/AA women.

Adaptation to Hypoxia May Promote Therapeutic Resistance to Androgen Receptor Inhibition in Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) surpasses other BC subtypes as the most challenging to treat due to its lack of traditional BC biomarkers. Nearly 30% of TNBC patients express the androgen receptor (AR), and the blockade of androgen production and AR signaling have been the cornerstones of therapies for AR-positive TNBC. However, the majority of women are resistant to AR-targeted therapy, which is a major impediment to improving outcomes for the AR-positive TNBC subpopulation. The hypoxia signaling cascade is frequently activated in the tumor microenvironment in response to low oxygen levels; activation of the hypoxia signaling cascade allows tumors to survive despite hypoxia-mediated interference with cellular metabolism. The activation of hypoxia signaling networks in TNBC promotes resistance to most anticancer drugs including AR inhibitors. The activation of hypoxia network signaling occurs more frequently in TNBC compared to other BC subtypes. Herein, we examine the (1) interplay between hypoxia signaling networks and AR and (2) whether hypoxia and hypoxic stress adaptive pathways promote the emergence of resistance to therapies that target AR. We also pose the well-supported question, “Can the efficacy of androgen-/AR-targeted treatments be enhanced by co-targeting hypoxia?” By critically examining the evidence and the complex entwinement of these two oncogenic pathways, we argue that the simultaneous targeting of androgen biosynthesis/AR signaling and hypoxia may enhance the sensitivity of AR-positive TNBCs to AR-targeted treatments, derail the emergence of therapy resistance, and improve patient outcomes.

Utility of green chemistry for native spectrofluorimetric quantification of darolutamide as a modern anti-neoplastic drug in its market form and biological fluids

A simple, new, green, and sensitive approach was established and validated for assay of the recently approved antineoplastic medication; darolutamide (DAR) in its authentic form, pharmaceutical formulation, and biological fluids fluorimetrically. This experiment relied on the native fluorescence of the cited drug and detects the ideal solvent utilized throughout the approach. The proposed approach was validated regarding linearity, accuracy, and precision. The calibration graph showed linearity over the range of 0.1-2.0 μg mL-1. The limit of detection and quantitation (LOD and LOQ) were 0.032 μg mL-1 and 0.09 μg mL-1, respectively. Because of the approach's high sensitivity, it was decided to spike the mentioned drug in plasma and urine samples. At last, checking for content uniformity was performed regarding the United States Pharmacopoeia (USP) by adjusting the proposed approach.

Approved spectrofluorimetric strategies for assurance of three modern antineoplastic drugs; Tepotinib, Sotorasib and Darolutamide in their dose forms and biological liquids utilizing mercurochrome

Approved, straightforward, fast and delicate spectrofluorimetric strategy has been developed for the estimation of tepotinib (TEPO), sotorasib (SOTO) and darolutamide (DARO) as a new antineoplastic drugs. Spectrofluorimetric strategy was based on quantitative fluorescence quenching of MER at 538 nm after being excited at 350 nm by the addition of cited drugs in presence of acetate buffer (pH 3.5). The degree of fluorescence quenching is directly proportional to the concentrations of the cited drugs within the concentration range of 0.5-10.0, 0.2-10 and 0.4-10.0 μg mL^-1 for TEPO, SOTO and DARO, respectively. Mean ± S.D. were calculated for the studied drugs as follows; 99.9±0.87, 99.72±1.08 and 100.21±1.44, for TEPO, SOTO and DARO, respectively. LOD values were 0.16, 0.05 and 0.11 μg mL^-1 while LOQ values were 0.5, 0.15 and 0.36 μg mL^-1 for TEPO, SOTO and DARO, respectively. Statistical comparison of comes about with those gotten by detailed strategies given great understanding and uncovered that there were no noteworthy contrasts in exactness and exactness between strategies. The proposed strategy was connected effectively to analyze measurement shapes containing the examined drugs. Moreover, the recommended fluorimetric strategy was connected for examination of TEPO, SOTO and DARO in human plasma and urine test.

Y06014 is a selective BET inhibitor for the treatment of prostate cancer

Bromodomain and extra-terminal proteins (BETs) are potential targets for the therapeutic treatment of prostate cancer (PC). Herein, we report the design, the synthesis, and a structure-activity relationship study of 6-(3,5-dimethylisoxazol-4-yl)benzo[cd]indol-2(1H)-one derivative as novel selective BET inhibitors. One representative compound, 19 (Y06014), bound to BRD4(1) in the low micromolar range and demonstrated high selectivity for BRD4(1) over other non-BET bromodomain-containing proteins. This molecule also potently inhibited cell growth, colony formation, and mRNA expression of AR-regulated genes in PC cell lines. Y06014 also shows stronger activity than the second-generation antiandrogen enzalutamide. Y06014 may serve as a new small molecule probe for further validation of BET as a molecular target for PC drug development.

A Systematic Comparison of Antiandrogens Identifies Androgen Receptor Protein Stability as an Indicator for Treatment Response

Antiandrogen therapy is a primary treatment for patients with metastasized prostate cancer. Whilst the biologic mechanisms of antiandrogens have been extensively studied, the operating protocols used for the characterization of these drugs were not identical, limiting their comparison. Here, the antiandrogens Bicalutamide, Enzalutamide, Apalutamide, and Darolutamide were systematically compared using identical experimental setups. Androgen-dependent LNCaP and LAPC4 cells as well as androgen-independent C4-2 cells were treated with distinct concentrations of antiandrogens. Androgen receptor (AR)-mediated gene transactivation was determined using qPCR. Cell viability was measured by WST1 assay. Protein stability and AR localization were determined using western blot. Response to the tested antiandrogens across cellular backgrounds differed primarily in AR-mediated gene transactivation and cell viability. Antiandrogen treatment in LNCaP and LAPC4 cells resulted in AR protein level reduction, whereas in C4-2 cells marginal decreased AR protein was observed after treatment. In addition, AR downregulation was already detectable after 4 h, whereas reduced AR-mediated gene transactivation was not observed before 6 h. None of the tested antiandrogens displayed an advantage on the tested parameters within one cell line as opposed to the cellular background, which seems to be the primary influence on antiandrogen efficacy. Moreover, the results revealed a prominent role in AR protein stability. It is one of the first events triggered by antiandrogens and correlated with antiandrogen efficiency. Therefore, AR stability may surrogate antiandrogen response and may be a possible target to reverse antiandrogen resistance.

Application of network pharmacology and molecular docking to elucidate the potential mechanism of Astragalus-Scorpion against prostate cancer

The present study aimed to investigate the molecular mechanism of the Astragalus-Scorpion drug pair in the treatment of prostate cancer (PCa). We employed network pharmacology and molecular docking technology to retrieving the active ingredients and corresponding targets of Astragalus-Scorpion by using TCMSP, BATMAN-TCM, TCMID and Swiss Target Prediction Databases. The targets related to PCa were retrieved through GeneCards. Cytoscape software was used to construct the 'active ingredient-target disease' network, and GO and KEGG enrichment analyses were performed on the common targets. Autodock software was used for molecular docking verification. In total, 26 active ingredients, 340 potential targets related to active ingredients and 122 common targets were screened from Astragalus-Scorpion drug pair. The core targets of the protein-protein interaction (PPI) network were JUN, AKT1, IL6, MAPK1 and RELA, whereas the core active ingredients were quercetin, kaempferol, formononetin, 7-o-methylisomucronulatol and calycosin. Nearly 762 GO entries and 154 pathways were obtained by using the pathway enrichment analysis. Molecular docking results revealed that quercetin and kaempferol bind to AKT1 and formononetin binds to RELA, all of which were found to be stable bounds.

Darolutamide in hormone-sensitive and castration-resistant prostate cancer

Introduction: Important changes in the treatment of prostate cancer have taken place in recent years. Non-metastatic castration-resistant prostate cancer (nmCRPC) has been clinically delineated. In this setting, three drugs have been approved in high-risk disease: apalutamide, enzalutamide and darolutamide.Areas covered:This manuscript aims to profile darolutamide, its clinical development, pharmacologic properties, efficacy and safety. We presented the results of published clinical studies, but we also investigated ongoing ones.Expert opinion: An indirect comparison with the other two aforementioned drugs emerged. While the clinical efficacy is comparable, the toxicity profile is different for darolutamide, resulting in greater tolerance. We must wait for the results of the trials that study darolutamide in hormone-sensitive disease, both in the metastatic phase and in the localized phase. Clinical experience will also be important to determine ever more personalized treatments for patients.

Volume matters and intensification is needed: emerging trends in the management of advanced prostate cancer

Significant changes in the management of patients with de novo metastatic prostate cancer have led to the use of novel oral agents and docetaxel-based chemotherapy earlier in the natural history of their disease. Our main challenge is the lack of prospective randomized data comparing these regimens. It is clear that treatment intensification is needed. Yet, the heterogeneity of this patient population coupled with the lack of understanding of the specific biology for a given individual makes treatment selection challenging. The aim of this narrative review is to discuss the importance of defining advanced disease by volume, the necessity for treatment intensification, and the current and future landscape of metastatic hormone-sensitive prostate cancer management.

A Clinical Evaluation of Enzalutamide in Metastatic Castration-Sensitive Prostate Cancer: Guiding Principles for Treatment Selection and Perspectives on Research

Enzalutamide was the first novel androgen receptor signaling inhibitor to demonstrate an overall survival benefit in non-metastatic and metastatic castration-sensitive prostate cancer (CSPC). It has emerged as one of the most commonly prescribed oral prostate cancer therapies (ARSI) by medical oncologists and urologists. Amongst a panoply of treatment options for metastatic CSPC, safe and effective utilization of enzalutamide dictates a detailed understanding of alternative therapy options and competing toxicity profiles. Ongoing research supports the potential for expanded enzalutamide use in earlier disease states, in combination with other systemic agents and as monotherapy (without androgen deprivation therapy). Optimal application of enzalutamide will ultimately require greater insight and attention to mitigating strategies for treatment-associated fatigue, cognitive impairment, and functional decline. This publication will comprehensively analyze the clinical evidence and guiding principles of enzalutamide use in CSPC. We will also provide a critical review of ongoing and future ARSI research focusing on pharmacologic approaches to overcome treatment resistance and strategies to improve treatment-associated functional impairment.

Gonadotropin-Releasing Hormone Receptors in Prostate Cancer: Molecular Aspects and Biological Functions

Pituitary Gonadotropin-Releasing Hormone receptors (GnRH-R) mediate the activity of the hypothalamic decapeptide GnRH, thus playing a key role in the regulation of the reproductive axis. Early-stage prostate cancer (PCa) is dependent on serum androgen levels, and androgen-deprivation therapy (ADT), based on GnRH agonists and antagonists, represents the standard therapeutic approach for PCa patients. Unfortunately, the tumor often progresses towards the more aggressive castration-resistant prostate cancer (CRPC) stage. GnRH receptors are also expressed in CRPC tissues, where their binding to both GnRH agonists and antagonists is associated with significant antiproliferative/proapoptotic, antimetastatic and antiangiogenic effects, mediated by the Gαi/cAMP signaling cascade. GnRH agonists and antagonists are now considered as an effective therapeutic strategy for CRPC patients with many clinical trials demonstrating that the combined use of these drugs with standard therapies (i.e., docetaxel, enzalutamide, abiraterone) significantly improves disease-free survival. In this context, GnRH-based bioconjugates (cytotoxic drugs covalently linked to a GnRH-based decapeptide) have been recently developed. The rationale of this treatment is that the GnRH peptide selectively binds to its receptors, delivering the cytotoxic drug to CRPC cells while sparing nontumor cells. Some of these compounds have already entered clinical trials.

Treatment and resistance mechanisms in castration-resistant prostate cancer: new implications for clinical decision making?

Introduction: The armamentarium of treatment options in metastatic and non-metastatic CRPC is rapidly evolving. However, the question of how individual treatment decisions should be balanced by available predictive clinical parameters, pharmacogenetic and drug interaction profiles, or compound-associated molecular biomarkers is a major challenge for clinical practice.Areas covered: We discuss treatment and resistance mechanisms in PC with regard to their association to drug efficacy and tolerability. Current efforts of combination treatment and putative predictive biomarkers of available and upcoming compounds are highlighted with regard to their implication on clinical decision-making.Expert opinion: Several treatment approaches are delineated, where identification of resistance mechanisms in CRPC may guide treatment selection. To date, most of these candidate biomarkers will however be found only in a small subset of patients. While current approaches of combination treatment in CRPC are proving synergistic effects on cancer biology, higher complexity with regard to biomarker analysis and interaction profiles of the respective compounds may be expected. Among other aspects of personalized treatment, consideration of drug-drug interaction and pharmacogenetics is an underrepresented issue. However, the non-metastatic castration resistant prostate cancer situation may be an example for treatment selection based on drug interaction profiles in the future.

Development of Androgen-Antagonistic Coumarinamides with a Unique Aromatic Folded Pharmacophore

First-generation nonsteroidal androgen receptor (AR) antagonists, such as flutamide (2a) and bicalutamide (3), are effective for most prostate cancer patients, but resistance often appears after several years due to the mutation of AR. Second-generation AR antagonists are effective against some of these castration-resistant prostate cancers, but their structural variety is still limited. In this study, we designed and synthesized 4-methyl-7-(N-alkyl-arylcarboxamido)coumarins as AR antagonist candidates and evaluated their growth-inhibitory activity toward androgen-dependent SC-3 cells. Coumarinamides with a secondary amide bond did not show inhibitory activity, but their N-methylated derivatives exhibited AR-antagonistic activity. Especially, 19b and 31b were more potent than the lead compound 7b, which was comparable to hydroxyflutamide (2b). Conformational analysis showed that the inactive coumarinamides with a secondary amide bond have an extended structure with a trans-amide bond, while the active N-methylated coumarinamides have a folded structure with a cis-amide bond, in which the two aromatic rings are placed face-to-face. Docking study suggested that this folded structure is important for binding to AR. Selected coumarinamide derivatives showed AR-antagonistic activity toward LNCaP cells with T877A AR, and they had weak progesterone receptor (PR)-antagonistic activity. The folded coumarinamide structure appears to be a unique pharmacophore, different from those of conventional AR antagonists.

Circulating-tumor DNA as predictor of enzalutamide response post-abiraterone treatment in metastatic castration-resistant prostate cancer

BACKGROUND

The crossover from abiraterone acetate (AA) to enzalutamide (ENZA) is a frequent approach in clinical practice. Our aim was to explore the role of genomic alterations as putative biomarkers of response to sequential AA followed by ENZA in mCRPC and their association with clinical outcomes.

PATIENTS AND METHODS

This was a multi-center, retrospective analysis of mCRPC patients with circulating-tumor DNA (ctDNA) post-AA and prior to ENZA treatment. Objectives of this analysis were to assess PSA response, time to PSA progression (TTP) and overall survival (OS) in mCRPC patients treated with ENZA following progression on AA with respect to genomic aberrations detected by ctDNA.

RESULTS

A total of 28 patients with mCRPC were identified. Median time between AA and ENZA was 3.1 months and median initial PSA prior to ENZA was 35.0 ng/mL. Nine patients (32.1%) achieved PSA responses to ENZA. Most patients (79.0%) achieved confirmed PSA progression with median TTP of 1.6 months (95% CI, 0.7-2.4). Somatic alterations in AR genes were detected in 36.0% of patients with other common alterations detected including 39.0% TP53, 11.0% DNA repair, and 11.0% PTEN. A lack of AR alterations was associated with better PSA response to ENZA (p = 0.04).

CONCLUSION

While lack of AR alterations in ctDNA was associated with more favorable outcomes, the present dataset is insufficient to recommend the use of ctDNA to impact clinical decision-making in this setting. Further understanding of the implications of the genomic phenotype in ctDNA of castration-resistant tumors and the potential therapeutic implications is required.

Darolutamide: An Evidenced-Based Review of Its Efficacy and Safety in the Treatment of Prostate Cancer

Men treated with androgen deprivation therapy for rising PSA after failed local therapy will often develop castrate resistance, and the appearance of metastases predicts a poor prognosis. Thus, researchers have long sought to prolong the onset of metastasis in patients with nonmetastatic castration-resistant prostate cancer (CRPC). Until 2018, patients in this group had no FDA-approved treatment options. They were typically managed with androgen-deprivation therapy (ADT) to maintain castrate systemic testosterone levels and given approved therapies for metastatic CRPC once metastases appeared. However, third-generation androgen receptor inhibitors (ARIs) have dramatically changed the treatment paradigm, having shown the ability to extend metastasis-free survival (MFS) significantly over ADT alone in Phase 3 trials. The newest of these, darolutamide, prolonged MFS 22 months over placebo while also improving a host of secondary and exploratory endpoints such as overall survival (OS), prostate-specific antigen (PSA) progression and time to pain progression, chemotherapy initiation, and symptomatic skeletal events. Among third-generation ARIs, darolutamide is unique in that it incorporates two pharmacologically active diastereomers and has demonstrated resistance to all known androgen receptor (AR) mutations. Additionally, patients taking darolutamide appear to experience comparatively few central nervous system-related adverse events (AEs) such as fatigue and falls, and no increases in seizures have been reported in the drug's clinical or preclinical development. Various authors attribute the low incidence of CNS-related AEs to darolutamide's minimal penetration of the blood-brain barrier (BBB). Other side effects ranging from hot flashes to hypothyroidism also occurred at rates similar to those of the placebo arm in Phase 3. As ADT in itself raises cardiovascular risk, the cardiovascular safety of third-generation antiandrogens as a category warrants continued scrutiny. In total, however, published data suggest that darolutamide provides a reasonable option for patients with nonmetastatic CRPC. Ongoing research will determine darolutamide's potential role in additional disease states such as localized and castration-sensitive PCa.

Mechanisms of Androgen Receptor Agonist- and Antagonist-Mediated Cellular Senescence in Prostate Cancer

The androgen receptor (AR) plays a leading role in the control of prostate cancer (PCa) growth. Interestingly, structurally different AR antagonists with distinct mechanisms of antagonism induce cell senescence, a mechanism that inhibits cell cycle progression, and thus seems to be a key cellular response for the treatment of PCa. Surprisingly, while physiological levels of androgens promote growth, supraphysiological androgen levels (SAL) inhibit PCa growth in an AR-dependent manner by inducing cell senescence in cancer cells. Thus, oppositional acting ligands, AR antagonists, and agonists are able to induce cellular senescence in PCa cells, as shown in cell culture model as well as ex vivo in patient tumor samples. This suggests a dual AR-signaling dependent on androgen levels that leads to the paradox of the rational to keep the AR constantly inactivated in order to treat PCa. These observations however opened the option to treat PCa patients with AR antagonists and/or with androgens at supraphysiological levels. The latter is currently used in clinical trials in so-called bipolar androgen therapy (BAT). Notably, cellular senescence is induced by AR antagonists or agonist in both androgen-dependent and castration-resistant PCa (CRPC). Pathway analysis suggests a crosstalk between AR and the non-receptor tyrosine kinase Src-Akt/PKB and the PI3K-mTOR-autophagy signaling in mediating AR-induced cellular senescence in PCa. In this review, we summarize the current knowledge of therapeutic induction and intracellular pathways of AR-mediated cellular senescence.

Renal and Cardiovascular Toxicities by New Systemic Treatments for Prostate Cancer

Prostate cancer (PC) is the most common male cancer in Western Countries. In recent years, the treatment of relapsed or metastatic disease had benefited by the introduction of a variety of new different drugs. In consideration of the relative long survival of PC patients, side effects of these drugs must be considered and monitored. In this review, we analyzed the newly developed therapies for PC treatment, describing the mechanism of action, the metabolism and latest clinical trials that led to the approval of these drugs in clinical practice. We then evaluated the cardiovascular and renal side effects from pivotal phase III and II studies and meta-analyses. Cardiovascular side effects are the most frequent, in particular hypertension, while renal toxicity is rarer and not well described in literature. Therefore, there is a need to better define the effects of these therapies, in order to personalize patient treatment on the basis of their comorbidities and preferences, in addition to their symptoms and disease load.

A novel androgen receptor antagonist JJ-450 inhibits enzalutamide-resistant mutant ARF876L nuclear import and function

BACKGROUND

Castration-resistant prostate cancer can develop resistance to enzalutamide because of androgen receptor (AR) point mutations, AR overexpression, constitutively active AR splice variants, and/or elevated intratumoral androgen synthesis. The point mutation AR^F876L was reported to be stimulated, instead of inhibited, by enzalutamide, thus contributing to enzalutamide resistance. We have recently developed JJ-450 as a novel AR antagonist with the potential to treat enzalutamide-resistant castration-resistant prostate cancer (CRPC).

METHODS

We employed several assays to determine the impact of JJ-450 and enzalutamide on prostate cancer cell lines expressing green fluorescent protein (GFP)-AR^F876L . These assays include a prostate-specific antigen enhancer/promoter-based luciferase assay to determine AR transcriptional activity, a quantitative real-time polymerase chain reaction assay, and Western blot analysis to detect expression of AR-target genes at the messenger RNA and protein level, fluorescence microscopy to show AR subcellular localization, and a 5-bromo-2'-deoxyuridine assay to measure prostate cancer cell proliferation.

RESULTS

As expected, enzalutamide inhibited wild-type (WT) AR but not AR^F876L transcriptional activity in the luciferase assay. In contrast, JJ-450 inhibited both WT-AR and AR^F876L transcriptional activity to a similar extent. Also, enzalutamide retarded androgen-induced nuclear import of GFP-AR, but not GFP-AR^F876L , whereas JJ-450 retarded nuclear import of both GFP-AR and GFP-AR^F876L . To further evaluate JJ-450 inhibition of AR^F876L , we stably transfected C4-2 cells separately with GFP-AR or GFP-AR^F876L . Enzalutamide inhibited endogenous AR-target gene expression in C4-2-GFP-AR^WT , but not in the C4-2-GFP-AR^F876L subline, whereas JJ-450 inhibited AR-target gene expression in both C4-2 sublines. More importantly, enzalutamide inhibited proliferation of C4-2-GFP-AR^WT , but not of the C4-2-GFP-AR^F876L subline, whereas JJ-450 inhibited proliferation of both C4-2 sublines.

CONCLUSION

JJ-450 inhibits enzalutamide-resistant AR^F876L mutant nuclear translocation and function. Our findings suggest that JJ-450 and its analogs should be further developed to provide a potential new approach for the treatment of enzalutamide-resistant CRPC.

Syringaresinol as a novel androgen receptor antagonist against wild and mutant androgen receptors for the treatment of castration-resistant prostate cancer: molecular docking, in-vitro and molecular dynamics study

Phytoestrogens are dietary estrogens having similar structure as of estrogen. Some of these phytoestrogens are androgen receptor (AR) antagonists and exhibit preventive role in the prostate cancer. However, in androgen-independent prostate cancer (AIPC) the ARs were mutated (T877A, W741L, F876L, etc.) and these mutant ARs convert the antagonist to agonist. Our aim in this study is to find phytoestrogens that could function as an antagonist with wild and mutant ARs. The phytoestrogens were analyzed for binding affinity with wild and mutant ARs in agonist and antagonist conformations. The point mutations were carried out using Chimera. The antagonist AR conformation was modeled using Modeller. We hypothesize that the compounds having binding affinity with agonist AR conformation could not function as a full or pure antagonist. Most of the phytoestrogens have binding affinity with agonist AR conformation contradicting previous results. For example, genistein which is a widely studied isoflavone has known AR antagonist property. However, in our study, it had good binding affinity with agonist AR conformation. Hence, to confirm our hypothesis, we tested genistein in LNCaP (T877A mutant AR) cells by qPCR studies. The genistein functioned as an antagonist only in the presence of an androgen indicting a partial agonist type of activity. The in-vitro results supported our docking hypothesis. We applied this principle and found syringaresinol could function as an antagonist with wild and mutated ARs. Further, we carried out molecular dynamics for the hit molecule to confirm its antagonist binding mode with mutant AR.Communicated by Ramaswamy H. Sarma.

Therapies Targeted to Androgen Receptor Signaling Axis in Prostate Cancer: Progress, Challenges, and Hope

Prostate cancer is the mostly commonly diagnosed non-cutaneous malignancy and the second leading cause of cancer-related death affecting men in the United States. Moreover, it disproportionately affects the men of African origin, who exhibit significantly greater incidence and mortality as compared to the men of European origin. Since androgens play an important role in the growth of normal prostate and prostate tumors, targeting of androgen signaling has remained a mainstay for the treatment of aggressive prostate cancer. Over the years, multiple approaches have been evaluated to effectively target the androgen signaling pathway that include direct targeting of the androgens, androgen receptor (AR), AR co-regulators or other alternate mechanisms that impact the outcome of androgen signaling. Several of these approaches are currently in clinical practice, while some are still pending further development and clinical evaluation. This remarkable progress has resulted from extensive laboratory, pre-clinical and clinical efforts, and mechanistic learnings from the therapeutic success and failures. In this review, we describe the importance of androgen signaling in prostate cancer biology and advances made over the years to effectively target this signaling pathway. We also discuss emerging data on the resistance pathways associated with the failure of various androgen signaling- targeted therapies and potential of this knowledge for translation into future therapies for prostate cancer.

Non-Steroidal Androgen Receptor Antagonists and Prostate Cancer: A Survey on Chemical Structures Binding this Fast-Mutating Target

The Androgen Receptor (AR) pathway plays a major role in both the pathogenesis and progression of prostate cancer. In particular, AR is chiefly involved in the development of Castration-Resistant Prostate Cancer (CRPC) as well as in the resistance to the secondgeneration AR antagonist enzalutamide, and to the selective inhibitor of cytochrome P450 17A1 (CYP17A1) abiraterone. Several small molecules acting as AR antagonists have been designed and developed so far, also as a result of the ability of cells expressing this molecular target to rapidly develop resistance and turn pure receptor antagonists into ineffective or event detrimental molecules. This review covers a survey of most promising classes of non-steroidal androgen receptor antagonists, also providing insights into their mechanism of action and efficacy in treating prostate cancer.

Second-Generation Antiandrogens: From Discovery to Standard of Care in Castration Resistant Prostate Cancer

Prostate cancer is the most commonly diagnosed cancer affecting men in the United States. The prostate is a hormone-dependent gland in which androgen hormones testosterone and dihydrotestosterone bind to and activate the androgen receptor, initiating nuclear translocation of androgen receptor and a subsequent signaling cascade. Due to the androgen dependency of the prostate, androgen deprivation therapies have emerged as first line treatment for aggressive prostate cancer. Such therapies are effective until the point at which prostate cancer, through a variety of mechanisms including but not limited to generation of ligand-independent androgen receptor splice variants, or intratumoral androgen production, overcome hormone deprivation. These cancers are androgen ablation resistant, clinically termed castration resistant prostate cancer (CRPC) and remain incurable. First-generation antiandrogens established androgen receptor blockade as a therapeutic strategy, but these therapies do not completely block androgen receptor activity. Efficacy and potency have been improved by the development of second-generation antiandrogen therapies, which remain the standard of care for patients with CRPC. Four second-generation anti-androgens are currently approved by the Food and Drug Administration (FDA); abiraterone acetate, enzalutamide, and recently approved apalutamide and darolutamide. This review is intended to provide a thorough overview of FDA approved second-generation antiandrogen discovery, treatment application, strategies for combination therapy to overcome resistance, and an insight for the potential future approaches for therapeutic inhibition of androgen receptor.

Androgen receptor modulators: a review of recent patents and reports (2012-2018)

INTRODUCTION

Androgen receptor (AR) is one of the most promising targets of drug discovery because of its importance in male reproductive systems and homeostasis of bone and muscle. Various AR-modulating agents have been developed and used clinically to treat androgen-dependent disorders, including prostate cancer, and some new-generation antiandrogens have recently been approved. Intensive studies are underway to develop various AR-modulating compounds, including conventional antagonists, tissue-specific AR modulators (SARMs), degraders, and nonconventional AR-modulating compounds that target sites other than the ligand-binding domain (LBD), such as the N-terminal domain (NTD) or the DNA-binding domain (DBD).

AREAS COVERED

The authors provide an overview of AR-modulating agents from 2012 to 2018.

EXPERT OPINION

The LBD has been the primary target for AR modulation, and important AR-modulating agents, including SARMs and recently approved antiandrogens such as enzalutamide and apalutamide, have been developed as conventional LBD antagonists. Development of LBD-targeting antiandrogens to treat prostate cancer is a kind of cat-and-mouse game between clinical agents and AR mutations, and therefore next-generation antiandrogens are still required. Development of nonconventional AR-modulating agents targeting NTD and DBD, is likely to be a promising approach to develop multiple and synergistic strategies able to overcome any kind of androgen-dependent condition.

The Current Landscape of Treatment in Non-Metastatic Castration-Resistant Prostate Cancer

Non-metastatic castration-resistant prostate cancer (nmCRPC) is a heterogeneous disease with variable potential in developing into overt metastases. It is an area of increased unmet need in advanced prostate cancer and for which there had been no great treatments until recent US Food and Drug Administration (FDA) approval of 2 novel anti-androgens apalutamide and enzalutamide, which were both approved given benefit in metastasis-free survival. Early data on the use of darolutamide, another novel anti-androgen, are also explored. This review discusses the pivotal trials that led to the approval of apalutamide and enzalutamide in the nmCRPC setting and discusses the key promises and challenges with the use of these agents.

Timing of androgen deprivation monotherapy and combined treatments in castration-sensitive and castration-resistant prostate cancer: a narrative review

PURPOSE

Standard androgen deprivation therapy (ADT) can be initiated early at the time of diagnosis in asymptomatic castration-sensitive advanced prostate cancer. This definition has recently been expanded to also include an early combined treatment with standard ADT and new antihormonal drugs. We aimed to present the best available evidence for the timing of initiation of ADT monotherapy and combined treatments in castration-sensitive/-resistant prostate cancer.

METHODS

For this narrative review, we searched Cochrane reviews in the Cochrane Library, systematic reviews and randomized controlled trials in MEDLINE, phase III and ongoing trials in ClinicalTrials.gov and screened the reference lists to extract articles of interest. One author screened the references which were finally included after assessing their relevance through discussion with other experts in the field.

RESULTS

The identified references were grouped by medication (standard ADT, androgen biosynthesis inhibitor, androgen receptor antagonists or combined therapies) and tumor stage (castration sensitive or resistant). The evidence was narratively summarized and discussed in the context of the current therapeutic landscape.

CONCLUSIONS

Early standard ADT can reduce symptoms of disease progression and may extend progression-free and overall survival. The patient should be well informed about the higher rates of treatment-related side effects. Deferring standard ADT might be indicated only for well-informed or unfit patients. Early standard ADT is increasingly combined with new antihormonal drugs in castration-sensitive metastatic prostate cancer to gain additional survival and quality of life benefits. Combined treatment at the time of development of castration-resistant disease is well established.

Investigational luteinizing hormone releasing hormone (LHRH) agonists and other hormonal agents in early stage clinical trials for prostate cancer

INTRODUCTION

The treatment and management of prostate cancer continues to evolve; newer classes of agents and combination therapies are being developed and some are being investigated in early phase clinical trials.

AREAS COVERED

We discuss investigational hormonal agents for the treatment of prostate cancer and focus primarily on luteinizing hormone releasing hormone (LHRH) agonists in early stage trials. We look at agents that target the hormonal axis, including anti-androgens, gonadotropins, estrogenic agents and progestogenic agents and other non-hormonal agents often used in combination with LHRH agonists. We review these candidates in the specific clinical niche in which they might find utility.

EXPERT OPINION

Of all candidate compounds being evaluated in clinical trials, very few will receive FDA approval. Few, if any of the investigational agents discussed here will be used routinely in clinical practice for treating prostate cancer. Recognizing the reasons for the failure of agents to advance to later stage trials is important. Furthermore, a thorough understanding of the mechanisms underlying prostate cancer pathogenesis, including various points in the HGPA and parallel pathways, will help identify potentially actionable targets.

Perspectives on the current and emerging chemical androgen receptor antagonists for the treatment of prostate cancer

INTRODUCTION

 Prostate cancer is the most common cancer in men. Regardless of the initial treatment of localized disease, almost all patients develop castration resistant prostate cancer (CRPC). A better understanding of the molecular mechanisms behind castration resistance has led to the approval of novel oral androgen receptor (AR) antagonists, such as enzalutamide and apalutamide. Indeed, research has accelerated with numerous agents being studied for the management of CRPC. Areas covered: Herein, the authors present currently used and emerging AR antagonists for the treatment of CRPC. Emerging agents include darolutamide, EZN-4176, AZD-3514, and AZD-5312, apatorsen, galeterone, ODM-2014, TRC-253, BMS-641988, and proxalutamide. Expert opinion: Further understanding of the mechanisms leading to castration resistance in prostate cancer can reveal potential targets for the development of novel AR antagonists. Current novel agents are associated with modest clinical and survival benefit, while acquired resistance and safety issues are under continuous evaluation. The combination of AR antagonists used and ideal sequencing strategies are key tasks ahead, along with the investigation of molecular biomarkers for future personalized targeted therapies. In the future, the challenge will be to determine an AR antagonist with the best combination of outcome and tolerability.

Clinical Development of Darolutamide: A Novel Androgen Receptor Antagonist for the Treatment of Prostate Cancer

Prostate cancer (PC) is the second most common cancer in men and is the fifth leading cause of cancer-related deaths among men. Androgen receptor (AR) signaling plays a key role in PC tumor growth and progression, with androgens stimulating PC proliferation and survival. Castration-resistant PC (CRPC) is characterized by increasing levels of prostate-specific antigen or radiographic progression despite androgen-deprivation therapy (ADT). In most patients, castration resistance results from aberrations in AR or the AR signaling pathway. Up to one-third of patients with localized high-risk PC will have disease progression on local therapy and develop CRPC. This review summarizes the key clinical data, including ongoing trials, for hormonal therapies in CRPC and provides an overview of the clinical development of darolutamide, a novel, nonsteroidal AR antagonist currently in phase III development for the treatment of nonmetastatic CRPC and metastatic hormone-sensitive PC. In phase I/II trials, darolutamide has demonstrated a favorable safety profile, antitumor activity, and significant decreases in prostate-specific antigen in patients with metastatic CRPC. In the phase III ARAMIS (NCT02200614; A Multinational, Randomized, Double-Blind, Placebo-Controlled, Phase III Efficacy and Safety Study of Darolutamide [ODM-201] in Men With High-Risk Non-metastatic Castration-Resistant Prostate Cancer) study, metastasis-free survival is being evaluated in men with nonmetastatic CRPC who will receive ADT in combination with darolutamide or placebo. The ARASENS (NCT02799602; A Randomized, Double-Blind, Placebo Controlled Phase III Study of Darolutamide [ODM-201] Versus Placebo in Addition to Standard Androgen Deprivation Therapy and Docetaxel in Patients With Metastatic Hormone Sensitive Prostate Cancer) study is a placebo-controlled trial assessing whether the addition of darolutamide to ADT and docetaxel significantly prolongs overall survival in men with metastatic hormone-sensitive PC.

Castration-Resistant Prostate Cancer: Sequencing Oral and Infusion Agents

PURPOSE OF REVIEW

To update treatment options and considerations for castration-resistant prostate cancer with specific attention to sequencing of agents based on available evidence and treatment rationale.

RECENT FINDINGS

The newest research developments over the last several years include multicenter studies that address the sequencing of therapies to improve the treatment of metastatic castration-resistant prostate cancer. Chemotherapy agents, as well as androgen receptor antagonists, are evolving, and there are new tests available to define which patients are more likely to benefit. In addition, there have been some additional trials looking into the safety and efficacy of combination treatment and new therapies. There are multiple factors that should be considered to determine the sequence and/or combinations of therapies for metastatic castration-resistant prostate cancer that can improve quality of life and survival. Promising novel agents in combination with personalized medicine will likely continue to improve treatment of these patients.

Management of nonmetastatic castration-resistant prostate cancer

PURPOSE OF REVIEW

The widespread use of prostate-specific antigen (PSA) resulted in stage migration of prostate cancer where androgen deprivation therapy (ADT) is administered for biochemical recurrence in patients following primary treatment. A proportion of these patients progress to a disease state termed nonmetastatic castration-resistant prostate cancer (nmCRPC), with a rising PSA despite ADT and without evidence of metastases on conventional imaging. We will review the treatment options in nmCRPC, especially in light of recent trials showing significant improvement in metastasis-free survival with newer agents.

RECENT FINDINGS

Historically, nmCRPC patients were followed-up if PSA doubling-time (PSADT) exceeded 10 months. Treatment options for patients with shorter PSADT included hormonal manipulations that often resulted in transient PSA decline. Denosumab was found to delay the onset of bone metastasis but did not impact survival. Recently, phase 3 trials showed that second-generation antiandrogens resulted in a significant delay in metastasis and a trend toward survival improvement in a select group of nmCRPC patients.

SUMMARY

The importance of reducing mortality and morbidity associated with metastasis has led to the acceptance of new primary endpoints in the design of trials for nmCRPC and might result in widespread approval of new agents for this disease state.