Efficacy and safety of enzalutamide versus bicalutamide for patients with metastatic prostate cancer (TERRAIN): a randomised, double-blind, phase 2 study

Risk of Fractures and Falls in Men with Advanced or Metastatic Prostate Cancer Receiving Androgen Deprivation Therapy and Treated with Novel Androgen Receptor Signalling Inhibitors: A Systematic Review and Meta-analysis of Randomised Controlled Trials

CONTEXT

The addition of androgen receptor signalling inhibitors (ARSIs) to standard androgen deprivation therapy (ADT) has improved survival outcomes in patients with advanced prostate cancer (PCa). Advanced PCa patients have a higher incidence of osteoporosis, compounded by rapid bone density loss upon commencement of ADT resulting in an increased fracture risk. The effect of treatment intensification with ARSIs on fall and fracture risk is unclear.

OBJECTIVE

To assess the risk of falls and fractures in men with PCa treated with ARSIs.

EVIDENCE ACQUISITION

A systematic review of EMBASE, MEDLINE, The Cochrane Library, and The Health Technology Assessment Database for randomised control trials between 1990 and June 2023 was conducted in accordance with Preferred Reporting Items for Systematic Review and Meta-analyses guidance. Risk ratios were estimated for the incidence of fracture and fall events. Subgroup analyses by grade of event and disease state were conducted.

EVIDENCE SYNTHESIS

Twenty-three studies were eligible for inclusion. Fracture outcomes were reported in 17 studies (N = 18 811) and fall outcomes in 16 studies (N = 16 537). A pooled analysis demonstrated that ARSIs increased the risk of fractures (relative risk [RR] 2.32, 95% confidence interval [CI] 2.00-2.71; p < 0.01) and falls (RR 2.22, 95% CI 1.81-2.72; p < 0.01) compared with control. A subgroup analysis demonstrated an increased risk of both fractures (RR 2.13, 95% CI 1.70-2.67; p < 0.01) and falls (RR 2.19, 95% CI 1.53-3.12; p < 0.0001) in metastatic hormone-sensitive PCa patients, and an increased risk of fractures in the nonmetastatic (RR 2.27, 95% CI 1.60-3.20; p < 0.00001) and metastatic castrate-resistant (RR 2.85, 95% CI 2.16-3.76; p < 0.00001) settings. The key limitations include an inability to distinguish fragility from pathological fractures and potential for a competing risk bias.

CONCLUSIONS

Addition of an ARSI to standard ADT significantly increases the risk of fractures and falls in men with prostate cancer.

PATIENT SUMMARY

We found a significantly increased risk of both fractures and falls with a combination of novel androgen signalling inhibitors and traditional forms of hormone therapy.

Comparative effectiveness of first-line systemic treatments for metastatic castration-resistant prostate cancer: a systematic review and network meta-analysis

OBJECTIVES

No head-to-head trials had been performed to estimate the relative effectiveness of poly ADP-ribose polymerase inhibitor (PARPi) and androgen receptor signaling inhibitor (ARSi) in the first-line treatment for metastatic castration-resistant prostate cancer (mCRPC). We aimed to perform a systematic review and network meta-analysis to evaluate the comparative effectiveness of various systemic treatment agents for patients with mCRPC.

METHODS

A comprehensive literature search was conducted for abstracts and full-text articles from the database's inception through April 27, 2023. The study concentrated on assessing radiographic progression-free survival (rPFS) for both overall and homologous recombination repair mutation (HRRm) population, with overall survival (OS) as the secondary measure. Under the Bayesian framework, the overall effect was pooled using the fixed-effects model in base case analysis. Scenario analysis using restricted mean survival time (RMST) methods was performed to test the robustness of the results.

RESULTS

Nine studies with 6,830 patients and 8 unique treatment options were included. Network meta-analysis demonstrated that talazoparib in combination with enzalutamide (TALA + ENZA; overall population, hazard ratio [HR], 0.20; 95% credible interval [CrI]: 0.16-0.26; RMST, 3.51; 95% confidence interval [CI] 2.46-4.60; HRRm population, HR, 0.15; 95% CrI: 0.09-0.23; RMST, 4.14; 95% CI 2.84-5.39) was superior to other treatments in the first-line setting in terms of rPFS. The results of Bayesian framework and RMST models showed consistent efficacy ranks. When extrapolated to overall survival benefit, within the Bayesian framework, olaparib plus abiraterone acetate and prednisone (OLAP + AAP) achieved the highest OS benefit for the overall population, which was not statistically significant when compared to TALA + ENZA. However, TALA + ENZA achieved the highest OS benefit at 3 years by applying RMST.

CONCLUSIONS

We suggest that talazoparib in combination with enzalutamide is probably a preferred treatment agent for the overall population and HRRm patients with mCRPC. Given the limitations of network framework and the modeling assumptions undertaken to finalize the analyses, results should be cautiously interpreted.

Current uses and resistance mechanisms of enzalutamide in prostate cancer treatment

INTRODUCTION

Prostate cancer continues to be a major cause of morbidity and mortality for men worldwide. Enzalutamide, a second-generation non-steroidal antiandrogen that blocks androgen receptor (AR) transcriptional activity, is a treatment for biochemically recurrent, metastatic, castration-sensitive, and castration-resistant tumors. Unfortunately, most patients ultimately develop resistance to enzalutamide, making long-term treatment with this agent challenging.

AREAS COVERED

We performed a literature search of PubMed without date restrictions to investigate the literature surrounding enzalutamide and discuss the current uses of enzalutamide, proposed mechanisms driving resistance, and summarize current efforts to mitigate this resistance.

EXPERT OPINION

Enzalutamide is an effective prostate cancer therapy that is currently used in biochemically recurrent and metastatic disease and for both castration-sensitive and castration-resistant tumors. Unfortunately, resistance to enzalutamide occurs in each of these scenarios. In the clinical setting, enzalutamide-resistant tumors are either AR-driven or AR-indifferent. AR-dependent resistance mechanisms include genomic or epigenomic events that result in enhanced AR signaling. Tumors that do not require AR signaling instead may depend on alternative oncogenic pathways. There are numerous strategies to mitigate enzalutamide resistance, including concurrent use of PARP inhibitors or immune therapies. Additional work is required to uncover novel approaches to treat patients in the enzalutamide-resistant setting.

Cardiovascular events among men with prostate cancer treated with androgen receptor signaling inhibitors: a systematic review, meta-analysis, and network meta-analysis

BACKGROUND

Androgen-receptor pathway inhibitors (ARPIs) have dramatically changed the management of advanced/metastatic prostate cancer (PCa). However, their cardiovascular toxicity remains to be clarified.

OBJECTIVE

To analyze and compare the risks of cardiovascular events secondary to treatment of PCa patients with different ARPIs.

METHODS

In August 2023, we queried PubMed, Scopus, and Web of Science databases to identify randomized controlled studies (RCTs) that analyze PCa patients treated with abiraterone, apalutamide, darolutamide, and enzalutamide. The primary outcomes of interest were the incidence of cardiac disorder, heart failure, ischemic heart disease (IHD), atrial fibrillation (AF), and hypertension. Network meta-analyses (NMAs) were conducted to compare the differential outcomes of each ARPI plus androgen deprivation therapy (ADT) compared to standard of care (SOC).

RESULTS

Overall, 26 RCTs were included. ARPIs were associated with an increased risk of cardiac disorders (RR: 1.74, 95% CI: 1.13-2.68, p = 0.01), heart failure (RR: 2.49, 95% CI: 1.05-5.91, p = 0.04), AF (RR: 2.15, 95% CI: 1.14-4.07, p = 0.02), and hypertension (RR: 2.06, 95% CI: 1.67-2.54, p < 0.01) at grade ≥3. Based on NMAs, abiraterone increased the risk of grade ≥3 cardiac disorder (RR:2.40, 95% CI: 1.42-4.06) and hypertension (RR:2.19, 95% CI: 1.77-2.70). Enzalutamide was associated with the increase of grade ≥3 AF(RR: 3.17, 95% CI: 1.05-9.58) and hypertension (RR:2.30, 95% CI: 1.82-2.92).

CONCLUSIONS

The addition of ARPIs to ADT increases the risk of cardiac disorders, including IHD and AF, as well as hypertension. Each ARPI exhibits a distinct cardiovascular event profile. Selecting patients carefully and vigilant monitoring for cardiovascular issues is imperative for those undergoing ARPI + ADT treatment.

Exploring the top 30 drugs associated with drug-induced constipation based on the FDA adverse event reporting system

Objective

This project aims to identify the top 30 drugs most commonly associated with constipation and their signal values within the FDA Adverse Event Reporting System database.

Methods

We extracted adverse drug events (ADEs) related to constipation from the FAERS database spanning from January 1, 2004, to September 30, 2023. We compiled the 30 most frequently reported drugs based on the frequency of constipation events. We employed signal detection methodologies to ascertain whether these drugs elicited significant signals, including reporting odds ratio, proportional reporting ratio, multi-item gamma Poisson shrinker, and information component given by the Bayesian confidence propagation neural network. Furthermore, we conducted a time-to-onset (TTO) analysis for drugs generating significant signals using the medians, quartiles, and the Weibull shape parameter test.

Results

We extracted a total of 50, 659, 288 ADEs, among which 169,897 (0.34%) were related to constipation. We selected and ranked the top 30 drugs. The drug with the highest ranking was lenalidomide (7,730 cases, 4.55%), with the most prevalent drug class being antineoplastic and immunomodulating agents. Signal detection was performed for the 30 drugs, with constipation risk signals identified for 26 of them. Among the 26 drugs, 22 exhibited constipation signals consistent with those listed on the FDA-approved drug labels. However, four drugs (orlistat, nintedanib, palbociclib, and dimethyl fumarate) presented an unexpected risk of constipation. Ranked by signal values, sevelamer carbonate emerged as the drug with the strongest risk signal [reporting odds ratio (95% CI): 115.51 (110.14, 121.15); PRR (χ2): 83.78 (191,709.73); EBGM (EB05): 82.63 (79.4); IC (IC025): 6.37 (4.70)]. A TTO analysis was conducted for the 26 drugs that generated risk signals, revealing that all drugs exhibited an early failure type. The median TTO for orlistat was 3 days, the shortest of all the drugs, while the median TTO for clozapine was 1,065 days, the longest of all the drugs.

Conclusion

Our study provides a list of drugs potentially associated with drug-induced constipation (DIC). This could potentially inform clinicians about some alternative medications to consider when managing secondary causes of constipation or caring for patients prone to DIC, thereby reducing the incidence and mortality associated with DIC.

Association mechanism of bicalutamide and human serum albumin for potential clinical implications

The binding mechanism of molecular interaction between bicalutamide and human serum albumin (HSA) in a pH 7.4 phosphate buffer was studied using various spectroscopic techniques in combination with molecular modeling. Fluorescence data revealed that the fluorescence quenching of HSA by bicalutamide was a static quenching procedure. The binding constants and number of binding sites were evaluated at different temperatures. The thermodynamic parameters, ΔH and ΔS, were calculated to be 4.30 × 104 J·mol-1 and 245 J·mol-1·K-1, respectively, suggesting that the binding of bicalutamide to HSA was driven mainly by hydrophobic interactions and hydrogen bonds. The displacement studies indicated neither Sudlow's site I nor II but subdomain IB as the main binding site for bicalutamide on HSA. The binding distance between bicalutamide and HSA was determined to be 3.54 nm based on the Förster theory. Analysis of circular dichroism, synchronous, and 3D fluorescence spectra demonstrated that HSA conformation was slightly altered in the presence of bicalutamide.

Sialylation Inhibition Can Partially Revert Acquired Resistance to Enzalutamide in Prostate Cancer Cells

Prostate cancer is a lethal solid malignancy and a leading cause of cancer-related deaths in males worldwide. Treatments, including radical prostatectomy, radiotherapy, and hormone therapy, are available and have improved patient survival; however, recurrence remains a huge clinical challenge. Enzalutamide is a second-generation androgen receptor antagonist that is used to treat castrate-resistant prostate cancer. Among patients who initially respond to enzalutamide, virtually all acquire secondary resistance, and an improved understanding of the mechanisms involved is urgently needed. Aberrant glycosylation, and, in particular, alterations to sialylated glycans, have been reported as mediators of therapy resistance in cancer, but a link between tumour-associated glycans and resistance to therapy in prostate cancer has not yet been investigated. Here, using cell line models, we show that prostate cancer cells with acquired resistance to enzalutamide therapy have an upregulation of the sialyltransferase ST6 beta-galactoside alpha-2,6-sialyltransferase 1 (ST6GAL1) and increased levels of α2,6-sialylated N-glycans. Furthermore, using the sialyltransferase inhibitor P-SiaFNEtoc, we discover that acquired resistance to enzalutamide can be partially reversed by combining enzalutamide therapy with sialic acid blockade. Our findings identify a potential role for ST6GAL1-mediated aberrant sialylation in acquired resistance to enzalutamide therapy for prostate cancer and suggest that sialic acid blockade in combination with enzalutamide may represent a novel therapeutic approach in patients with advanced disease. Our study also highlights the potential to bridge the fields of cancer biology and glycobiology to develop novel combination therapies for prostate cancer.

EAU-EANM-ESTRO-ESUR-ISUP-SIOG Guidelines on Prostate Cancer. Part II-2024 Update: Treatment of Relapsing and Metastatic Prostate Cancer

BACKGROUND AND OBJECTIVE

The European Association of Urology (EAU)-European Association of Nuclear Medicine (EANM)-European Society for Radiotherapy and Oncology (ESTRO)-European Society of Urogenital Radiology (ESUR)-International Society of Urological Pathology (ISUP)-International Society of Geriatric Oncology (SIOG) guidelines on the treatment of relapsing, metastatic, and castration-resistant prostate cancer (PCa) have been updated. Here we provide a summary of the 2024 guidelines.

METHODS

The panel performed a literature review of new data, covering the time frame between 2020 and 2023. The guidelines were updated and a strength rating for each recommendation was added on the basis of a systematic review of the evidence.

KEY FINDINGS AND LIMITATIONS

Risk stratification for relapsing PCa after primary therapy may guide salvage therapy decisions. New treatment options, such as androgen receptor-targeted agents (ARTAs), ARTA + chemotherapy combinations, PARP inhibitors and their combinations, and prostate-specific membrane antigen-based therapy have become available for men with metastatic PCa.

CONCLUSIONS AND CLINICAL IMPLICATIONS

Evidence for relapsing, metastatic, and castration-resistant PCa is evolving rapidly. These guidelines reflect the multidisciplinary nature of PCa management. The full version is available online (http://uroweb.org/guideline/ prostate-cancer/).

PATIENT SUMMARY

This article summarises the 2024 guidelines for the treatment of relapsing, metastatic, and castration-resistant prostate cancer. These guidelines are based on evidence and guide doctors in discussing treatment decisions with their patients. The guidelines are updated every year.

Cardiovascular Events and Androgen Receptor Signaling Inhibitors in Advanced Prostate Cancer: A Systematic Review and Meta-Analysis

Importance

Cardiovascular (CV) events remain a substantial cause of mortality among men with advanced and metastatic prostate cancer (PCa). The introduction of novel androgen receptor signaling inhibitors (ARSI) has transformed the treatment landscape of PCa in recent years; however, their associated CV toxic effects remains unclear.

Objective

To assess the incidence of CV events with addition of ARSI to standard of care (SOC) in locally advanced (M0) and metastatic (M1) PCa.

Data Sources

Systematic searches of PubMed, Scopus, Web of Science, EMBASE, and ClinicalTrials.gov were performed from inception up to May 2023.

Study Selection

Randomized clinical trials of ARSI agents (abiraterone, apalutamide, darolutamide, enzalutamide) that reported CV events among individuals with M0 and M1, hormone-sensitive prostate cancer (HSPC) and castration-resistant prostate cancer (CRPC).

Data Extraction and Synthesis

A systematic review was performed in accordance with PRISMA guidance. Two authors screened and independently evaluated studies eligible for inclusion. Data extraction and bias assessment was subsequently performed.

Main Outcomes and Measures

A random-effects meta-analysis was performed to estimate risk ratios for the incidence of all grade and grade 3 or higher CV events (primary outcomes), in addition to hypertension, acute coronary syndrome (ACS), cardiac dysrhythmia, CV death, cerebrovascular event, and venous thromboembolism (secondary outcomes). Sources of heterogeneity were explored using meta-regression.

Results

There were 24 studies (n = 22 166 patients; median age range, 63-77 years; median follow-up time range, 3.9-96 months) eligible for inclusion. ARSI therapy was associated with increased risk of all grade CV event (risk ratio [RR], 1.75; 95% CI, 1.50-2.04; P < .001) and grade 3 or higher CV events (RR, 2.10; 95%, 1.72-2.55; P < .001). ARSI therapy also was associated with increased risk for grade 3 or higher events for hypertension (RR, 2.25; 95% CI, 1.74-2.90; P < .001), ACS (RR, 1.93; 95% CI, 1.43-1.60; P < .01), cardiac dysrhythmia (RR, 1.64; 95% CI, 1.23-2.17; P < .001), cerebrovascular events (RR, 1.86; 95% CI, 1.34-2.59; P < .001) and for CV-related death (RR, 2.02; 95% CI, 1.32-3.10; P = .001). Subgroup analysis demonstrated increased risk of all CV events across the disease spectrum (M0 HSPC: RR, 2.26; 95% CI, 1.36-3.75; P = .002; M1 HSPC: RR, 1.85; 95% CI, 1.47-2.31; P < .001; M0 CRPC: RR, 1.79; 95% CI, 1.13-2.81; P = .01; M1 CRPC: RR, 1.46; 95% CI, 1.16-1.83; P = .001).

Conclusions and Relevance

This systematic review and meta-analysis found that the addition of ARSIs to traditional ADT was associated with increased risk of CV events across the prostate cancer disease spectrum. These results suggest that patients with prostate cancer should be advised about and monitored for the potential of increased risk of CV events with initiation of ARSI therapy alongside conventional hormonal therapy.

Proteomic profiling of prostate cancer reveals molecular signatures under antiandrogen treatment

BACKGROUND

Tumorigenesis and progression of prostate cancer (PCa) are indispensably dependent on androgen receptor (AR). Antiandrogen treatment is the principal preference for patients with advanced PCa. However, the molecular characteristics of PCa with antiandrogen intervention have not yet been fully uncovered.

METHODS

We first performed proteome analysis with 32 PCa tumor samples and 10 adjacent tissues using data-independent acquisition (DIA)- parallel accumulation serial fragmentation (PASEF) proteomics. Then label-free quantification (LFQ) mass spectrometry was employed to analyze protein profiles in LNCaP and PC3 cells.

RESULTS

M-type creatine kinase CKM and cartilage oligomeric matrix protein COMP were demonstrated to have the potential to be diagnostic biomarkers for PCa at both mRNA and protein levels. Several E3 ubiquitin ligases and deubiquitinating enzymes (DUBs) were significantly altered in PCa and PCa cells under enzalutamide treatment, and these proteins might reprogram proteostasis at protein levels in PCa. Finally, we discovered 127 significantly varied proteins in PCa samples with antiandrogen therapy and further uncovered 4 proteins in LNCaP cells upon enzalutamide treatment.

CONCLUSIONS

Our research reveals new potential diagnostic biomarkers for prostate cancer and might help resensitize resistance to antiandrogen therapy.

A Rare Case of Bicalutamide-Induced Severe Congestive Heart Failure in a Patient With Advanced Prostate Cancer

Bicalutamide, a nonsteroidal androgen receptor inhibitor, is an established therapeutic agent for advanced prostate cancer but is associated with severe cardiovascular side effects in rare cases. This case report discusses a rare occurrence of severe systolic congestive heart failure (CHF) in a 68-year-old male undergoing treatment for advanced prostate cancer with bicalutamide, without concurrent use of gonadotropin-releasing hormone antagonists. The patient presented with non-specific abdominal and bilateral foot pain. The initial assessment indicated anemia and severe dyspnea, revealing a significant decrease in left ventricular ejection fraction (LVEF) from 55% to 15% on transthoracic echocardiography (TTE), indicative of severe CHF. Bicalutamide was identified as the likely culprit given the temporal association and lack of other identifiable causes, leading to its discontinuation and initiation of guideline-directed medical therapy (GDMT). A remarkable recovery of cardiac function was subsequently observed, with LVEF improving to 60%. The patient was managed with GDMT, and a gonadotropin-releasing hormone antagonist, degarelix, was later introduced for prostate cancer treatment, along with ongoing cardiac monitoring. The recovery of LVEF and the absence of other etiologies reinforce the likelihood of bicalutamide-induced cardiotoxicity. This report underscores the importance of vigilant cardiovascular monitoring in patients receiving bicalutamide, prompt identification of cardiac dysfunction and possible mechanisms of bicalutamide cardiotoxicity, and the potential for cardiac recovery upon drug discontinuation and initiation of GDMT.

A net-work meta-analysis of the cardiac safety for next-generation hormonal agents in treating castration-resistant prostate cancer: How to choose drugs appropriately?

BACKGROUND

Researchers have shown that using next-generation hormonal agents (NHA) for castration-resistant prostate cancer (CRPC) would lead to increased risk of cardiac adverse effects, making clinician choices more complex.

METHODS

We systematically searched Pubmed, Cochrane Library, and Embase databases for research published before October 2022. Agents were ranked according to their effectiveness based on cardiac adverse effects using the surface under the cumulative ranking curve.

RESULTS

A total of 21 Randomized Controlled Trials (RCT) with 19, 083 patients were included in present study. Our results showed that abiraterone and enzalutamide could lead to a significantly higher hypertension rate compared with placebo; whereas no significant difference was detected between four NHAs and placebo in ischemic heart disease incidence. All four NHAs could significantly increase the risk of cardiotoxicity.

CONCLUSIONS

NHAs are generally acceptable in terms of cardiovascular disease compared to placebo in patients with CRPC.

Long-Term Efficacy and Safety of Enzalutamide Monotherapy in Elderly Patients with Metastatic Castration-Resistant Prostate Cancer: A Case Report

Introduction

Prostate cancer is one of the most common cancers in men. Despite the sharp rise in incidence, mortality is decreasing. ARTA preparations are preferred options for asymptomatic or mildly symptomatic patients with mCRPC. The use of enzalutamide in elderly patients with mCRPC is risky and depends on a number of factors. An increased risk of falls and fractures has been shown.

Case Presentation

We present a case report of an elderly patient with mCRPC treated with enzalutamide with very good long-term tolerance and efficacy.

Conclusion

Despite the older age, no reduction of therapy was necessary in the patient due to good tolerance. Administration of enzalutamide in full doses resulted in a very good effect of therapy.

Central Nervous System-related Conditions and Associated Healthcare Resource Use Among Japanese nmCRPC Patients Based on Retrospective Claims Data

Background: Japanese patients with prostate cancer are typically treated with primary androgen deprivation therapy (ADT), most commonly administered as a combination of a luteinizing hormone-releasing hormone (LHRH) agonist and an antiandrogen (AA). Since LHRH agonists and AA therapy can be maintained for several years, the long-term effects of these treatments on patients must be carefully considered, including the risk of concomitant central nervous system (CNS) conditions which could affect treatment choices. Objective: To describe CNS-related concomitant conditions during ADT and/or AA treatment and the subsequent healthcare resource utilization in Japanese nonmetastatic castration-resistant prostate cancer (nmCRPC) patients. Methods: Patients diagnosed with nmCRPC and CNS-related conditions while on ADT and/or AA therapy between April 2009 and August 2017 were retrospectively followed up for a maximum of 2 years using a claims database. Results: A total of 455 patients (average age, 78.5 years), were included. The 3 most common concomitant CNS-related conditions were pain (~60% of events), insomnia (~30%), and headache (2%-3%). The frequency of CNS-related conditions in these patients increased approximately threefold after starting AA therapy (before, 969 events; after, 2802). On average, a patient had 10 episodes of concomitant CNS-related conditions in a year. Medical costs did not significantly increase due to CNS-related conditions. Discussion: The most frequently reported CNS-related conditions were pain, insomnia, and headaches. Furthermore, more concomitant CNS-related conditions 1 year after CRPC diagnosis and 1 year after starting AA treatment were recorded. Conclusion: Patients with nmCRPC experience an increase in the frequency of concomitant CNS-related conditions, including pain, insomnia, and headaches, after CRPC diagnosis or starting AA treatment. Future research should explore the causes of this increased frequency.

Cardiovascular Adverse Events Associated With New-Generation Androgen Receptor Pathway Inhibitors (ARPI) for Prostate Cancer: A Disproportionality Analysis Based on the FDA Adverse Event Reporting System (FAERS)

BACKGROUND

The potential cardiovascular adverse events associated with new-generation androgen receptor pathway inhibitors (ARPI) in the treatment of prostate cancer remain unclear. We aimed to assess the pharmacovigilance (PV), reporting rate, severity, and reaction outcomes of major adverse cardiovascular events (MACE) related to new-generation ARPI for prostate cancer reported to the United States Food and Drug Administration Adverse Event Reporting System (FAERS).

METHODS

We analyzed reports of cardiovascular adverse events associated with drug therapy for prostate cancer submitted to FAERS between January 2014 and December 2022. Three primary new-generation ARPIs were identified: abiraterone acetate, enzalutamide, and apalutamide. Our primary composite endpoint was the PV of MACE caused by ARPIs in the treatment of prostate cancer, and the secondary endpoint was PV of other cardiovascular events. The software implemented was STATA 17.0 MP.

RESULTS

A total of 278,031 suspected drug-adverse event pairs related to drug treatment in patients with prostate cancer were identified, of which 10,861 reports were cardiovascular events, including 5800 reports of MACE and 5061 reports of other cardiovascular events. The majority of these cardiovascular adverse event reports came from the United States (36.6%) and were mostly older men (age 76.0 ± 8.6 years). Compared with enzalutamide, the constituent ratio of MACE caused by abiraterone acetate and apalutamide was significantly increased, but the incidence of severe MACE decreased significantly. The PV signal regarding MACE was detected in abiraterone acetate and apalutamide but not in enzalutamide.

CONCLUSION

Abiraterone acetate and apalutamide presumably are associated with a higher risk of MACE than enzalutamide in new-generation ARPI for prostate cancer. More extensive prospective studies and more extended follow-up periods need to confirm this further.

Systemic Therapies for Metastatic Castration-Resistant Prostate Cancer: An Updated Review

The introduction of novel therapeutic agents for advanced prostate cancer has led to a wide range of treatment options for patients with metastatic castration-resistant prostate cancer (mCRPC). In the past decade, new treatment options for mCRPC, including abiraterone, enzalutamide, docetaxel, cabazitaxel, sipuleucel-T, radium-223, 177Lu-PSMA-617, and Olaparib, have demonstrated a survival benefit in phase 3 trials. Bone-modifying agents have become part of the overall treatment strategy for mCRPC, in which denosumab and zoledronic acid reduce skeletal-related events. Recently, androgen receptor-signaling inhibitors (ARSIs) and docetaxel have been used upfront against metastatic castration-sensitive prostate cancer. Further, triplet therapy with ARSI, docetaxel, and androgen deprivation therapy is emerging. However, cross-resistance may occur between these treatments, and the optimal treatment sequence must be considered. The sequential administration of ARSIs, such as abiraterone and enzalutamide, is associated with limited efficacy; however, cabazitaxel is effective for patients with mCRPC who were previously treated with docetaxel and had disease progression during treatment with ARSI. Radioligand therapy with 177Lu-PSMA-617 is a new effective class of therapy for patients with advanced PSMA-positive mCRPC. Tumors with gene alterations that affect homologous recombination repair, such as BRCA1 and BRCA2 alterations, are sensitive to poly (adenosine diphosphate-ribose) polymerase (PARP) inhibitors in mCRPC. This review sought to highlight recent advances in systemic therapy for mCRPC and strategies to support patient selection and treatment sequencing.

Impact of performance status on efficacy of systemic therapy for prostate cancer: a meta-analysis

OBJECTIVE

To evaluate the efficacy of systemic therapies in patients with worse performance status (PS) treated for high-risk non-metastatic prostate cancer (PCa), metastatic hormone-sensitive PCa (mHSPC), and non-metastatic/metastatic castration-resistant PCa (nmCRPC/mCRPC), as there is sparse pooled data showing the effect of PS on oncological outcomes in patients with PCa.

METHODS

Three databases were queried in June 2022 for randomised controlled trials (RCTs) analysing patients with PCa treated with systemic therapy (i.e., adding androgen receptor signalling inhibitor [ARSI] or docetaxel [DOC] to androgen-deprivation therapy [ADT]). We analysed the oncological outcomes of patients with PCa with worse PS, defined as Eastern Cooperative Oncology Group PS ≥ 1, treated with combination therapies and compared these to patients with good PS. The main outcomes of interest were overall survival (OS), metastasis-free survival (MFS), and progression-free survival.

RESULTS

Overall, 25 and 18 RCTs were included for systematic review and meta-analyses/network meta-analyses, respectively. In all clinical settings, combination systemic therapies significantly improved OS in patients with worse PS as well as in those with good PS, while the MFS benefit from ARSI in the nmCRPC setting was more pronounced in patients with good PS than in those with worse PS (P = 0.002). Analysis of treatment ranking in patients with mHSPC revealed that triplet therapy had the highest likelihood of improved OS irrespective of PS; specifically, adding darolutamide to DOC + ADT had the highest likelihood of improved OS in patients with worse PS. Analyses were limited by the small proportion of patients with a PS ≥ 1 (19%-28%) and that the number of PS 2 was rarely reported.

CONCLUSIONS

Among RCTs, novel systemic therapies seem to benefit the OS of patients with PCa irrespective of PS. Our findings suggest that worse PS should not discourage treatment intensification across all disease stages.

Targeted Therapy for Cancers: From Ongoing Clinical Trials to FDA-Approved Drugs

The development of targeted therapies has revolutionized cancer treatment, offering improved efficacy with reduced side effects compared with traditional chemotherapy. This review highlights the current landscape of targeted therapy in lung cancer, colorectal cancer, and prostate cancer, focusing on key molecular targets. Moreover, it aligns with US Food and Drug Administration (FDA)-approved drugs and drug candidates. In lung cancer, mutations in the epidermal growth factor receptor (EGFR) and anaplastic lymphoma kinase (ALK) gene rearrangements have emerged as significant targets. FDA-approved drugs like osimertinib and crizotinib specifically inhibit these aberrant pathways, providing remarkable benefits in patients with EGFR-mutated or ALK-positive lung cancer. Colorectal cancer treatment has been shaped by targeting the vascular endothelial growth factor (VEGF) and EGFR. Bevacizumab and cetuximab are prominent FDA-approved agents that hinder VEGF and EGFR signaling, significantly enhancing outcomes in metastatic colorectal cancer patients. In prostate cancer, androgen receptor (AR) targeting is pivotal. Drugs like enzalutamide, apalutamide, and darolutamide effectively inhibit AR signaling, demonstrating efficacy in castration-resistant prostate cancer. This review further highlights promising targets like mesenchymal-epithelial transition (MET), ROS1, BRAF, and poly(ADP-ribose) polymeras (PARP) in specific cancer subsets, along with ongoing clinical trials that continue to shape the future of targeted therapy.

An overview of hormonal directed pharmacotherapy for the treatment of prostate cancer

INTRODUCTION

Prostate cancer is the most common malignancy in the male. Androgen-deprivation therapy (ADT) has been the mainstay in the treatment of metastatic prostate cancer however, due to the outgrowth of castration-resistant cell population the disease inevitably progresses to an aggressive, difficult to handle stage.

AREAS COVERED

We have reviewed the literature regarding hormonal-directed therapy prostate cancer. New agents, namely abiraterone acetate, combined with prednisone, and next generation antiandrogens (enzalutamide, apalutamide and darolutamide) have shown considerable efficacy, not only in patients with metastatic but also in those with non-metastatic disease, either castration resistant (CRPC) or hormone sensitive (HSPC).

EXPERT OPINION

The addition of abiraterone and of the second-generation antiandrogens to our therapeutic armamentarium has improved prognosis ofprostate cancer in the last decade. Abiraterone is a viable option in patients with metastatic disease (hormone-sensitive and castration-resistant), whereas all next-generation antiandrogens have demonstrated efficacy in terms of metastasis-free and overall survival in non-metastatic CRPC. In addition, enzalutamide has also been found efficacious in mCRPC and mHSPC, while apalutamide in mHSPC. Currently there are no reliable data to indicate a potential superiority of one of these agents over the others in CRPC or HSPC as there are no relevant head to head studies . Sequencing hormone treatment modalities, chemotherapies and immunotherapies have not reached a consensus as yet. Randomized controlled trials are warranted to clearly define the role of novel antiandrogens in the treatment of prostate cancer. The choice of treatment should be individualized following discussion with the patient .

Newly identified adverse events of enzalutamide using the food and drug administration adverse event reporting system

OBJECTIVES

Enzalutamide, a second-generation anti-androgen drug, is an androgen receptor inhibitor developed to overcome resistance to first-generation anti-androgens, such as bicalutamide. This study aimed to identify previously undisclosed adverse events associated with enzalutamide.

METHODS

Adverse reactions following enzalutamide administration were extracted from the Food and Drug Administration Adverse Event Reporting System (FAERS) database, and the data obtained were from 2014 to 2023. Four algorithms, namely ROR, PRR, BCPNN, and EBGM, were used to detect signs of adverse reactions associated with enzalutamide use.

RESULTS

This study determined several adverse reactions in the nervous system, including hypogeusia, ageusia, dysgeusia, normal-pressure hydrocephalus, dementia, amnesia, balance disorders, and seizure-like phenomena. The mental aspects manifested as laziness, confusion, and eating disorders. Gastrointestinal system-related adverse reactions included dysphagia, constipation, fecal hardening, and abdominal discomfort. We identified several previously unreported adverse reactions, including normal-pressure hydrocephalus, dementia, balance disorders, eating disorders, and dysphagia.

CONCLUSION

Our study revealed novel adverse events associated with enzalutamide, particularly in the nervous system, that have not been previously documented. These findings have important implications for future clinical medication guidelines.

Adverse Events and Androgen Receptor Signaling Inhibitors in the Treatment of Prostate Cancer: A Systematic Review and Multivariate Network Meta-analysis

CONTEXT

Androgen receptor signaling inhibitor (ARSi) agents are emerging as standard treatments for prostate cancer across the disease spectrum, but much remains unknown regarding how their side-effect profiles compare.

OBJECTIVE

To systematically evaluate the literature regarding adverse events (AEs) between the ARSi drugs abiraterone, apalutamide, darolutamide, and enzalutamide in the treatment of metastatic castration-resistant prostate cancer (mCRPC), nonmetastatic CRPC (nmCRPC), and metastatic castration-sensitive prostate cancer (mCSPC).

EVIDENCE ACQUISITION

PubMed, Web of Science, and Embase were queried for double-blind, randomized controlled trials (RCTs) of ARSi therapy up to September 2022 according to the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) statement. Two teams reviewed titles and abstracts, and 14 RCTs were included for analysis.

EVIDENCE SYNTHESIS

Forest plots were used to summarize risk ratios for the most common AEs. According to surface under the cumulative ranking curve (SUCRA) values, enzalutamide was ranked as the most toxic treatment regarding hypertension outcomes (SUCRA 0%, most likely to be the bottom-ranked treatment) in both mCRPC and nmCRPC (SUCRA 0%). Enzalutamide was also ranked as the most toxic regarding headache across all prostate cancer entities (SUCRA 0%, for mCRPC, 1% for nmCRPC, and 3% for mCSPC).

CONCLUSIONS

Our findings suggest that the ARSi side-effect profiles do not significantly differ, except that enzalutamide was ranked the most toxic regarding hypertension in mCRPC and nmCRPC, and the most toxic regarding headache across all prostate cancer settings. These results highlight the importance of close blood-pressure monitoring for enzalutamide, and future research should explore possible connections between cardiovascular and neurological risk with ARSi therapy. In addition, these comparisons rely on the validity of cross-trial comparisons.

PATIENT SUMMARY

We reviewed the side-effect profiles of second-generation antiandrogen drugs for the treatment of prostate cancer. Side effects were similar, apart from higher risk of high blood pressure and headache risk with enzalutamide.

The efficacy and adverse events of conventional and second-generation androgen receptor inhibitors for castration-resistant prostate cancer: A network meta-analysis

Background

Second-generation androgen receptor inhibitors (ARIs) have been developed and approved for treating castration-resistant prostate cancer (CRPC). There is a lack of direct comparison of the therapeutic effects and adverse events between the conventional ARI (bicalutamide) and three second-generation ARIs (enzalutamide, apalutamide and darolutamide).

Methods

Our network meta-analysis evaluated therapeutic effects and adverse events of the conventional ARI (bicalutamide) and the second-generation ARIs in treating CRPC. We systematically searched the Pubmed, Cochrane library and Embase databases for studies published until October 2022 and only randomized clinical trials (RCTs) were included. The progression-free survival, prostate-specific antigen (PSA) progression-free survival, overall survival (PFS/PSA-PFS/OS), PSA response rate and relative adverse events (AEs) of CRPC patients were collected and synthesized. We then performed subgroup analysis. The non-metastatic and metastatic CRPC (nm/mCRPC) observations were analyzed separately. Data analyses were performed using R software (4.2.1) based on Bayesian framework.

Results

6,993 subjects from seven eligible RCTs were analyzed. Enzalutamide, apalutamide and darolutamide were more effective than bicalutamide in treating CRPC, and the performance of darolutamide was slightly worse than the other two second-generation ARIs. Similar adverse events rate were observed among the second-generation ARIs and bicalutamide. Apalutamide showed a slightly higher rate of Grade 3+ AEs, percentages of AE-related drug withdrawals and AE-related mortality. Patients receiving enzalutamide had significantly higher rate of hypertension and fatigue. In subgroup analysis, enzalutamide showed better therapeutic effects compared with bicalutamide in both nmCRPC and mCRPC groups. In nmCRPC group, enzalutamide and apalutamide had more benefits on PFS and PSA-PFS compared with darolutamide. We displayed the probability ranking map of PFS, PSA-PFS, OS, time to cytotoxic chemotherapy, PSA response rate and relative AE outcomes.

Conclusion

The current network meta-analysis indicated that the second-generation ARIs were superior to the conventional ARI, bicalutamide. The three second-generation ARIs showed incomplete equivalence on CRPC treatment. The darolutamide was slightly less effective compared with enzalutamide and apalutamide. The adverse events of apalutamide were worse than the others, but no statistical significance was observed among these vital AEs. All ARIs were generally well-tolerated. These results may provide reference to clinical decision and further direct comparison trials.

Systematic review registration

https://www.crd.york.ac.uk/PROSPERO, identifier CRD42022370842.

Mechanisms of Prostate Cancer Cells Survival and Their Therapeutic Targeting

Prostate cancer (PCa) is today the second most common cancer in the world, with almost 400,000 deaths annually. Multiple factors are involved in the etiology of PCa, such as older age, genetic mutations, ethnicity, diet, or inflammation. Modern treatment of PCa involves radical surgical treatment or radiation therapy in the stages when the tumor is limited to the prostate. When metastases develop, the standard procedure is androgen deprivation therapy, which aims to reduce the level of circulating testosterone, which is achieved by surgical or medical castration. However, when the level of testosterone decreases to the castration level, the tumor cells adapt to the new conditions through different mechanisms, which enable their unhindered growth and survival, despite the therapy. New knowledge about the biology of the so-called of castration-resistant PCa and the way it adapts to therapy will enable the development of new drugs, whose goal is to prolong the survival of patients with this stage of the disease, which will be discussed in this review.

Low-Dose Enzalutamide in Metastatic Prostate Cancer-Longevity Over Conventional Survival Analysis

BACKGROUND

Enzalutamide is an important drug in the treatment of prostate cancer. Standard dosing often requires dose reduction because of side effects. There is no information on survival outcomes with lower doses. We investigated the impact of starting enzalutamide at ≤ 50% dose on metastatic prostate cancer outcomes including patients' longevity.

PATIENTS AND METHODS

Records of metastatic prostate cancer patients treated with enzalutamide at one center were retrospectively reviewed. Low-dose enzalutamide (≤80 mg/day) was compared with standard-dose (160 mg/day). The primary objective was to compute the restricted mean survival time (RMST - time scale) and restricted mean attained age (RMAA - age scale) using the Irwin method. Secondary objectives included overall survival (OS), progression-free survival (PFS), and PSA progression per PCWG3 criteria (PSA PFS). We used the logrank test and the ∆ difference between RMSTs for comparison.

RESULTS

Of 111 patients treated, 32 received a low-dose and 79 the standard-dose. Low-dose patients had less prior abiraterone or chemotherapy (28.1% vs. 65.8%, P < .001); more testosterone assessment (65.6% vs. 40.5%, P = .016); poorer ECOG performance status (48.3% score ≥2 vs. 26.6%; P = .040), more comorbidities (75.9% vs. 46.3%; P = .010)) including increased cardiovascular disease (51.7% vs. 21.4%, P = .004). Baseline PSA value and doubling time at start of enzalutamide and distribution of metastases were similar between the groups. OS and PFS did not differ between low-dose and standard-dose. Patients on low-dose had a better longevity with significantly longer RMAA, 89.1 years, versus standard-dose RMAA of 83.8 years (∆ = 5.3 years, P = .003, logrank P = .025). In a subgroup analysis by age at start of enzalutamide, <75 versus ≥75 years old, longevity was also better with low-dose in younger patients (∆ = 2.9 years, P = .034, and older, ∆ = 3.3 years, P = .011).

CONCLUSION

The longevity advantage and reduced adverse events seen in patients with prostate cancer treated with low-dose enzalutamide warrants further investigation.

Risk of cognitive impairment in men with advanced prostate cancer treated with NHAs: A systematic review and network meta-analysis

Novel hormonal agents (NHAs) have significantly improved outcomes in men with advanced prostate cancer. However, it remains unclear whether NHAs are associated with subsequent cognitive impairment. Thus, we sought to perform a network meta-analysis to compare the risk of cognitive impairment across NHA types. Databases (PubMed, Embase, Scopus, and Web of Science), trial registries (Clinicaltrial.gov), the European Medicines Agency, and the US Food and Drug Administration drug safety reports were searched from inception through July 30, 2021. Eligible studies were clinical trials evaluating the risk of cognitive impairment between NHAs and placebo/standard care. Two independent investigators extracted the data and performed quality assessments using the Cochrane Risk of Bias Tool and ROBINS-I. We estimated the risk ratios by the frequentist approach and calculated the ranking probabilities of all treatments with the surface under the cumulative ranking probabilities. The primary outcome and secondary outcome were odds ratio (OR) and incidence rate ratio of cognitive impairment, respectively. We identified 15 trials with 14,723 participants comparing HNAs with placebo/standard care. Treatments associated with cognitive impairment, from the most to the least, were enzalutamide (OR, 3.66; 95% confidence interval [CI], 2.84-4.73), apalutamide (OR, 1.76; 95% CI, 1.08-2.87), abiraterone acetate (OR, 1.64; 95% CI, 1.01-2.45), and darolutamide (OR, 1.11 95% CI, 0.51-2.39). After adjustment of treatment time duration, enzalutamide still had the highest risk of cognitive impairment with an incidence rate ratio of 2.17 (95% CI, 1.65-2.78). These findings suggest that NHAs, especially enzalutamide, may increase the risk of cognitive impairment compared with placebo/standard care.

Transcriptional profiling of matched patient biopsies clarifies molecular determinants of enzalutamide-induced lineage plasticity

The androgen receptor (AR) signaling inhibitor enzalutamide (enza) is one of the principal treatments for metastatic castration-resistant prostate cancer (CRPC). Several emergent enza clinical resistance mechanisms have been described, including lineage plasticity in which the tumors manifest reduced dependency on the AR. To improve our understanding of enza resistance, herein we analyze the transcriptomes of matched biopsies from men with metastatic CRPC obtained prior to treatment and at progression (n = 21). RNA-sequencing analysis demonstrates that enza does not induce marked, sustained changes in the tumor transcriptome in most patients. However, three patients' progression biopsies show evidence of lineage plasticity. The transcription factor E2F1 and pathways linked to tumor stemness are highly activated in baseline biopsies from patients whose tumors undergo lineage plasticity. We find a gene signature enriched in these baseline biopsies that is strongly associated with poor survival in independent patient cohorts and with risk of castration-induced lineage plasticity in patient-derived xenograft models, suggesting that tumors harboring this gene expression program may be at particular risk for resistance mediated by lineage plasticity and poor outcomes.

Synthesis of Hydantoin Androgen Receptor Antagonists and Study on Their Antagonistic Activity

Hydroxymethylthiohydantoin, hydroxymethylthiohydantoin, and hydantoin, containing a pyridine group, were synthesized to study their androgen receptor antagonistic activities. Among them, compounds 6a/6c/7g/19a/19b exhibited excellent androgen receptor antagonistic activity, which was consistent with or even superior to enzalutamide. In addition, compounds 19a and 19b exhibited better antiproliferative activity than enzalutamide in prostate cancer cells. The results show that compound 19a has great potential as a new AR antagonist.

Emerging hormonal agents for the treatment of prostate cancer

INTRODUCTION

Prostate cancer is the most common solid organ malignancy in men in the United States. Until recently, treatment options for men with metastatic disease were limited and patients faced poor outcomes with minimal alternatives. The landscape of prostate cancer treatment has transformed and taken shape over the last 20 years with novel hormonal and non-hormonal therapeutics that have demonstrated significant improvement in survival. However, patients with advanced disease still face imminent progression on hormone blockade therapy.

AREAS COVERED

There is a significant market opportunity to devise novel, more potent agents for patients with hormone-resistant disease. Here we review the existing treatment options in men with advanced prostate cancer, the market opportunity within this field, goals of current research, and the novel agents under investigation, including androgen receptor degraders, testosterone synthesis pathway inhibitors, DNA-binding domain and N-terminal domain antagonists, and the combination of hormonal and non-hormonal agents.

EXPERT OPINION

Combination therapy regimens and novel agents targeting alternative binding domains of the androgen receptor are of great interest, as they may overcome resistance mechanisms and hold promise as the future of advanced prostate cancer treatment.

Androgen receptor axis‑targeted agents are not superior to conventional hormonal therapy for treatment of metastatic prostate cancer

The present study aimed to use real-world Japanese data to compare the treatment outcome of conventional hormonal therapy to that of using androgen receptor axis-targeted (ARAT) agents for patients with metastatic castration-resistant prostate cancer. The overall survival between the conventional hormonal therapy group and the ARAT agent therapy group was compared using a group of 75 Japanese patients who were treated for metastatic castration-resistant prostate cancer. A subgroup analysis was carried out and the risk factors that affected overall survival (OS) were determined. The median OS from the time of prostate-specific antigen recurrence was 73.1 months in the ARAT group and 45.2 months in the conventional treatment group (P=0.414). Although OS tended to be slightly longer in the ARAT group, the difference between the groups was not significant. Subgroup analysis suggested that the therapeutic outcome of using ARAT agents tended to be less beneficial in patients who were older, and in those with a higher tumor volume or low Gleason grade. In conclusion, use of ARAT agents did not impart a significant survival benefit to patients with metastatic castration-resistant prostate cancer when compared with survival rates in response to conventional therapy. However, there was some clinical benefit when ARAT agents were used after patients developed castration-resistant prostate cancer. These findings suggest that up-front therapy using ARAT agents at the time of the initial hormone therapy can impart clinical benefit in Japanese patients with metastatic prostate cancer.

CDK6 is upregulated and may be a potential therapeutic target in enzalutamide-resistant castration-resistant prostate cancer

Background

Androgen deprivation therapy (ADT) is still the first-line treatment of prostate cancer (PCa). However, after a certain period of therapy, primary PCa inevitably progresses into castration-resistant PCa (CRPC). Enzalutamide (Enz) is an androgen receptor (AR) signal inhibitor which can delay the progression of CRPC and increase survival of patients with metastatic CRPC. However, the mechanisms involved in enzalutamide-resistant (EnzR) CRPC are still controversial. In the study, we used bioinformatic methods to find potential genes that correlated with the occurrence of EnzR CRPC.

Methods

We collected RNA sequencing data of the EnzR CRPC cell line LNCaP (EnzR LNCaP) from GSE44905, GSE78201, and GSE150807. We found the hub genes from the three datasets. Then we tested the expression of the hub genes in different databases and the potential drugs that can affect the hub genes. Finally, we verified the hub gene expression and drug function.

Results

From GSE44905, GSE78201 and GSE150807, we found 45 differentially expressed genes (DEGs) between LNCaP and EnzR LNCaP. Ten hub genes were found in the protein–protein interaction (PPI) network. The expression of hub gene and survival analysis were analyzed by different databases. We found that cyclin-dependent kinase 6 (CDK6) was highly expressed in both the EnzR LNCaP cell and PCa patients. Ten potential small molecules could suppress CDK6 expression as per “CLUE COMMAND” findings. Finally, we found the expression of CDK6 increased in both PCa patients’ samples, CRPC and EnzR PCa cell lines. Three potential CDK6 inhibitors, namely apigenin, chrysin and fisetin, can decrease cell proliferation.

Conclusions

The study proved that the abnormal overexpression of CDK6 may be a reason behind EnzR CRPC occurrence and suppression CDK6 expression may help treat EnzR CRPC.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40001-022-00730-y.

From Therapy Resistance to Targeted Therapies in Prostate Cancer

Prostate cancer (PCa) is the second most common malignancy among men worldwide. Although early-stage disease is curable, advanced stage PCa is mostly incurable and eventually becomes resistant to standard therapeutic options. Different genetic and epigenetic alterations are associated with the development of therapy resistant PCa, with specific players being particularly involved in this process. Therefore, identification and targeting of these molecules with selective inhibitors might result in anti-tumoral effects. Herein, we describe the mechanisms underlying therapy resistance in PCa, focusing on the most relevant molecules, aiming to enlighten the current state of targeted therapies in PCa. We suggest that selective drug targeting, either alone or in combination with standard treatment options, might improve therapeutic sensitivity of resistant PCa. Moreover, an individualized analysis of tumor biology in each PCa patient might improve treatment selection and therapeutic response, enabling better disease management.

Inhibition of Cyclin-Dependent Kinase 8/Cyclin-Dependent Kinase 19 Suppresses Its Pro-Oncogenic Effects in Prostate Cancer

Progression of prostate cancer (PCa) is characterized by metastasis and castration resistance after response to androgen deprivation. Therapeutic options are limited, causing high morbidity and lethality. Recent work reported pro-oncogenic implications of the Mediator subunits cyclin-dependent kinase (CDK) 8 and 19 for the progression of PCa. The current study explored the underlying molecular mechanisms of CDK8/CDK19 and tested effects of novel CDK8/CDK19 inhibitors. PC3, DU145, LNCaP, and androgen-independent LNCaP Abl were used for in vitro experiments. Two inhibitors and CDK19 overexpression were used to modify CDK8/CDK19 activity. MTT assay, propidium iodide staining, wound healing assay, Boyden chamber assay, and adhesion assay were used to investigate cell viability, cell cycle, migration, and adhesion, respectively. Peptide-kinase screen using the PamGene platform was conducted to identify phosphorylated targets. Combining CDK8/CDK19 inhibitors with anti-androgens led to synergistic antiproliferative effects and sensitized androgen-independent cells to bicalutamide. CDK8/CDK19 inhibition resulted in reduced migration and increased collagen I-dependent adhesion. Phosphorylation of multiple peptides linked to cancer progression was identified to be dependent on CDK8/CDK19. In summary, this study substantially supports recent findings on CDK8/CDK19 in PCa progression. These findings contribute to a better understanding of underlying pro-oncogenic effects, which is needed to develop CDK8/CDK19 as a therapeutic target in PCa.

Rational Second-Generation Antiandrogen Use in Prostate Cancer

The second-generation antiandrogens have achieved an ever-growing list of approvals and indications in subsets of prostate cancer. Here, we provide an overview of second-generation antiandrogen trials and FDA approvals and outline a rational sequencing approach for the use of these agents as they relate to chemotherapy and other available treatment modalities in advanced prostate cancer. All published phase II-III randomized controlled trials reporting outcomes with the use of second-generation antiandrogens in prostate cancer are included as well as all published trials and retrospective studies of second-generation antiandrogen sequencing and/or combinations. Complete tabular and graphical representation of all available evidence is provided regarding the use and sequencing of second-generation antiandrogens in prostate cancer. In metastatic castration-resistant prostate cancer, evidence suggests prioritization of abiraterone before chemotherapy, chemotherapy after second-generation antiandrogen failure, and postchemotherapy enzalutamide in select patients to maximize agent efficacy and tolerability. We conclude that a rational, optimized sequencing of second-generation antiandrogens with other treatment options is feasible with present data.

Effect of enzalutamide on PK of P-gp and BCRP substrates in cancer patients: CYP450 induction may not always predict overall effect on transporters

Drug‐drug interaction (DDI) is an important consideration for clinical decision making in prostate cancer treatment. The objective of this study was to evaluate the effect of enzalutamide, an oral androgen receptor inhibitor, on the pharmacokinetics (PK) of digoxin (P‐glycoprotein [P‐gp] probe substrate) and rosuvastatin (breast cancer resistance protein [BCRP] probe substrate) in men with metastatic castration‐resistant prostate cancer (mCRPC). This was a phase I, open‐label, fixed‐sequence, crossover study (NCT04094519). Eligible men with mCRPC received a single dose of transporter probe cocktail containing 0.25 mg digoxin and 10 mg rosuvastatin plus enzalutamide placebo‐to‐match on day 1. On day 8, patients started 160 mg enzalutamide once daily through day 71. On day 64, patients also received a single dose of the cocktail. The primary end points were digoxin and rosuvastatin plasma maximum concentration (C_max), area under the concentration‐time curve from the time of dosing to the last measurable concentration (AUC_last), and AUC from the time of dosing extrapolated to time infinity (AUC_inf). Secondary end points were enzalutamide and N‐desmethyl enzalutamide (metabolite) plasma C_max, AUC during a dosing interval, where tau is the length of the dosing interval (AUC_tau), and concentration immediately prior to dosing at multiple dosing (C_trough). When administered with enzalutamide, there was a 17% increase in C_max, 29% increase in AUC_last, and 33% increase in AUC_inf of plasma digoxin compared to digoxin alone, indicating that enzalutamide is a “mild” inhibitor of P‐gp. No PK interaction was observed between enzalutamide and rosuvastatin (BCRP probe substrate). The PK of enzalutamide and N‐desmethyl enzalutamide were in agreement with previously reported data. The potential for transporter‐mediated DDI between enzalutamide and digoxin and rosuvastatin is low in men with prostate cancer. Therefore, concomitant administration of enzalutamide with medications that are substrates for P‐gp and BCRP does not require dose adjustment in this patient population.

The prostate cancer landscape in Europe: Current challenges, future opportunities

Prostate cancer (PCa) is the most common non-cutaneous cancer in men in Europe and is predicted to exhibit declining mortality in the European Union (EU) due to various recent improvements in treatment. The goal of this short review is to give insight into the European treatment landscape of PCa, while focusing on improvements in care.

Cellular specificity of androgen receptor, coregulators, and pioneer factors in prostate cancer

Androgen signalling, through the transcription factor androgen receptor (AR), is vital to all stages of prostate development and most prostate cancer progression. AR signalling controls differentiation, morphogenesis, and function of the prostate. It also drives proliferation and survival in prostate cancer cells as the tumour progresses; given this importance, it is the main therapeutic target for disseminated disease. AR is also essential in the surrounding stroma, for the embryonic development of the prostate and controlling epithelial glandular development. Stromal AR is also important in cancer initiation, regulating paracrine factors that excite cancer cell proliferation, but lower stromal AR expression correlates with shorter time to progression/worse outcomes. The profile of AR target genes is different between benign and cancerous epithelial cells, between castrate-resistant prostate cancer cells and treatment-naïve cancer cells, between metastatic and primary cancer cells, and between epithelial cells and fibroblasts. This is also true of AR DNA-binding profiles. Potentially regulating the cellular specificity of AR binding and action are pioneer factors and coregulators, which control and influence the ability of AR to bind to chromatin and regulate gene expression. The expression of these factors differs between benign and cancerous cells, as well as throughout disease progression. The expression profile is also different between fibroblast and mesenchymal cell types. The functional importance of coregulators and pioneer factors in androgen signalling makes them attractive therapeutic targets, but given the contextual expression of these factors, it is essential to understand their roles in different cancerous and cell-lineage states.

The circRAB3IP Mediated by eIF4A3 and LEF1 Contributes to Enzalutamide Resistance in Prostate Cancer by Targeting miR-133a-3p/miR-133b/SGK1 Pathway

An increasing number of studies have shown that circRNAs are closely related to the carcinogenesis and development of prostate cancer (PCa). However, little is known about the effect of the biological functions of circRNAs on the enzalutamide resistance of PCa. Through bioinformatic analysis and experiments, we investigated the expression pattern of circRNAs in enzalutamide-resistant PCa cells. Quantitative real-time PCR was used to detect the expression of circRAB3IP, and plasmids that knock down or overexpress circRAB3IP were used to evaluate its effect on the enzalutamide sensitivity of PCa cells. Mechanistically, we explored the potential regulatory effects of eIF4A3 and LEF1 on the biogenesis of circRAB3IP. Our in vivo and in vitro data indicated that increased expression of circRAB3IP was found in enzalutamide-resistant PCa, and knockdown of circRAB3IP significantly enhanced enzalutamide sensitivity in PCa cells. However, upregulation of circRAB3IP resulted in the opposite effects. Further mechanistic research demonstrated that circRAB3IP could regulate the expression of serum and glucocorticoid-regulated kinase 1 (SGK1) by serving as a sponge that directly targets miR-133a-3p/miR-133b. Then, we showed that circRAB3IP partially exerted its biological functions via SGK1 signaling. Furthermore, we discovered that eIF4A3 and LEF1 might increase circRAB3IP expression in PCa.

Apalutamide radio-sensitisation of prostate cancer

INTRODUCTION

The combination of radiotherapy with bicalutamide is the standard treatment of prostate cancer patients with high-risk or locally advanced disease. Whether new-generation anti-androgens, like apalutamide, can improve the radio-curability of these patients is an emerging challenge.

MATERIALS AND METHODS

We comparatively examined the radio-sensitising activity of apalutamide and bicalutamide in hormone-sensitive (22Rv1) and hormone-resistant (PC3, DU145) prostate cancer cell lines. Experiments with xenografts were performed for the 22Rv1 cell line.

RESULTS

Radiation dose-response viability and clonogenic assays showed that apalutamide had a stronger radio-sensitising activity for all three cell lines. Confocal imaging for γΗ2Αx showed similar DNA double-strand break repair kinetics for apalutamide and bicalutamide. No difference was noted in the apoptotic pathway. A striking cell death pattern involving nuclear karyorrhexis and cell pyknosis in the G1/S phase was exclusively noted when radiation was combined with apalutamide. In vivo experiments in SCID and R2G2 mice showed significantly higher efficacy of radiotherapy (2 and 4 Gy) when combined with apalutamide, resulting in extensive xenograft necrosis.

CONCLUSIONS

In vitro and in vivo experiments support the superiority of apalutamide over bicalutamide in combination with radiotherapy in prostate cancer. Clinical studies are encouraged to show whether replacement of bicalutamide with apalutamide may improve the curability rates.

Real-world use of first-generation antiandrogens: impact on patient outcomes and subsequent therapies in metastatic castration-resistant prostate cancer

OBJECTIVES

To investigate the recent real-world use of first-generation antiandrogens (FGAs) in metastatic castration-resistant prostate cancer (mCRPC) using a retrospective multicentre cohort study.

PATIENTS AND METHODS

The electronic CRPC Australian Database (ePAD) was interrogated to identify patients with mCRPC. Clinicopathological features, treatment and outcome data, stratified by FGA use, were retrieved and reported through descriptive statistics. Survival analyses were calculated using the Kaplan-Meier method and groups compared using log-rank tests. Factors influencing overall survival (OS) were analysed using Cox proportional hazards regression model.

RESULTS

We identified 634 patients with mCRPC, enrolled in ePAD between January 2016 and March 2019, including 322 (51%) who received FGAs. The median follow-up was 21.9 months. Patients treated with FGAs were more likely to have lower International Society of Urological Pathologists (ISUP) grade group (P = 0.04), longer median time to CRPC (25.6 vs 16.0 months, P < 0.001), and were less likely to have visceral metastases (5.0% vs 11.2%, P = 0.005) or to have received upfront docetaxel (P < 0.001). A ≥50% reduction from pre-treatment prostate-specific antigen (PSA) level (PSA50 response) during FGA treatment occurred in 119 (37%) patients and was independently associated with improved OS (hazard ratio 0.233, P < 0.001). Prior FGA treatment did not significantly influence the selection of subsequent life-prolonging treatments for mCRPC or their PSA50 response rates.

CONCLUSION

In our present cohort, FGAs were commonly used in lower-risk mCRPC and their use did not significantly influence the choice or duration of subsequent systemic therapy. A PSA50 response to FGA therapy was an independent favourable prognostic marker associated with improved OS.

Risk for stroke and myocardial infarction with abiraterone versus enzalutamide in metastatic prostate cancer patients

Background

Abiraterone and enzalutamide use is associated with significant cardiovascular (CV) morbidity in clinical trials, but the magnitude and clinical relevance of this association in real-world prostate cancer (PC) population remain unknown.

Materials and methods

We retrospectively reviewed the MarketScan claims databases (1 January 2013 to 30 September 2018) to identify adults with diagnosis of metastatic PC who received treatment with androgen deprivation therapy (ADT) and novel antiandrogen agents (abiraterone or enzalutamide). The primary CV outcome measure was composite outcome of acute myocardial infarction (MI) or stroke. Secondary outcomes were individual risks of MI or stroke. We used an intention-to-treat approach to analyze the CV outcomes associated with drug exposure among patients with metastatic PC. Cox regression model was used to estimate the independent association of two drugs with CV risk after adjustment for age, baseline atrial fibrillation, and Charlson Comorbidity Index.

Results

A total of 6294 patients with metastatic PC who were treated with ADT and either abiraterone or enzalutamide were included in the final analysis. Of these, 4017 (63.8%) patients used abiraterone and 2217 (32.2%) patients used enzalutamide. During the study period, 255 (6.3%) primary endpoint events occurred, resulting in an incidence rate of 4.3 per 100 patient-years. In multivariable analysis, abiraterone use was associated with a 31% increased risk of MI or stroke compared to enzalutamide (hazard ratio 1.31; 95% confidence interval 1.05-1.63; P = 0.01). The incidence rate was similar in patients who switched initial therapy from abiraterone to enzalutamide or vice versa (5.0 versus 5.6 per 100 patient-years, respectively).

Conclusions

To our knowledge, this is the first real-world assessment of MI and stroke among metastatic PC patients receiving novel anti-androgens. Our findings of increased MI and stroke risk with abiraterone compared with enzalutamide are consistent with data from clinical trials and suggest that enzalutamide may be preferable for prostate cancer patients at high CV risk.

•

Abiraterone and enzalutamide have comparable efficacy but substantial differences in CV toxicity.

•

We identified metastatic PC patients treated with ADT and abiraterone or enzalutamide from insurance claims-based database.

•

Abiraterone use was associated with a 31% increased risk for MI or stroke when compared to enzalutamide.

•

Enzalutamide may be preferable in patients with baseline high CV risk.

Neurotoxicities of novel non-steroidal anti-androgens for prostate cancer: A systematic review and meta-analysis

INTRODUCTION

Novel non-steroidal anti-androgens (NSAA) are increasingly part of the management of prostate cancer. We aimed to quantify and compare the neurologic side effects of NSAA agents.

MATERIALS AND METHODS

Phase III randomized controlled trials evaluating NSAAs in the treatment of prostate cancer were selected by two reviewers independently in MEDLINE. A random-effects model and the Mantel-Haenszel method were used. The Odds Ratio (OR) and its 95 % confidence interval were computed. The primary endpoints were the rates of neurologic adverse events.

RESULTS

Eight phase III trials evaluating novel NSAAs (vs. non-NSAAs) were included. Fatigue (OR:1.66 [1.32-2.08]), falls (OR:1.76 [1.25-2.49]), headache (OR:1.74 [1.42-2.14]), and dizziness (OR:1.70 [1.33-2.19]) were found to be significantly associated with NSAA use.

CONCLUSIONS

NSAAs are associated with an increase in various neurologic adverse events. When NSAAs are prescribed, neurologic adverse event prevention and management strategies should be discussed and implemented.

Efficacy of enzalutamide in subgroups of men with metastatic hormone-sensitive prostate cancer based on prior therapy, disease volume, and risk

BACKGROUND

While enzalutamide plus androgen deprivation therapy (ADT) significantly reduces the risk of radiographic progression-free survival (rPFS) and improves overall survival in metastatic hormone-sensitive prostate cancer (mHSPC), the efficacy in clinically relevant subgroups of patients based on prior local and systemic therapy, disease volume, and risk has not been analyzed to date. These post hoc analyses of the phase 3 ARCHES trial (NCT02677896) evaluated the efficacy of enzalutamide plus ADT according to prior local and systemic treatment, disease volume, and risk, assessed at trial baseline.

METHODS

In ARCHES, a global, double-blind, placebo-controlled, phase 3 study, 1150 patients with mHSPC were randomized 1:1 to receive enzalutamide (160 mg/day) plus ADT or placebo plus ADT, stratified by prior docetaxel therapy and disease volume. Primary endpoint was rPFS. Secondary endpoints included time to prostate-specific antigen progression, symptomatic skeletal events, and prostate-specific antigen and radiographic responses. Analyses of clinical endpoints were completed by prior local therapy, prior docetaxel exposure, CHAARTED (NCT00309985)-defined disease volume, and LATITUDE (NCT01715285)-defined risk groups.

RESULTS

Patients were randomized to enzalutamide plus ADT (n = 574) and placebo plus ADT (n = 576). Enzalutamide plus ADT significantly improved rPFS (hazard ratio: 0.39; p < 0.0001), with similar improvements reported in all subgroups based on prior local and docetaxel treatment, disease volume, and risk. Treatment benefits were observed with enzalutamide plus ADT in multiple secondary clinical endpoints in the overall population and all subgroups.

CONCLUSIONS

Enzalutamide plus ADT demonstrated clinical benefit across all patients with mHSPC, irrespective of prior local and systemic treatment, disease volume, and risk.

Histone acetyltransferase 1 upregulates androgen receptor expression to modulate CRPC cell resistance to enzalutamide

Castration-resistant prostate cancer (CRPC) is the latest stage of PCa, and there is almost no effective treatment available for the patients with CRPC when next-generation androgen deprivation therapy drugs, such as enzalutamide (ENZ), fail. The androgen receptor (AR) plays key roles in PCa and CRPC progression and drug resistance. Histone acetyltransferase 1 (HAT1) has recently been reported to be highly expressed in some tumors, such as lung carcinoma. However, what relationship between the AR and HAT1, and whether or how HAT1 plays roles in CRPC progression and drug resistance remain elusive. In the present study, we found that HAT1 is highly expressed in PCa cells, and the overexpression of HAT1 is linked with CRPC cell proliferation. Moreover, the HAT1 expression is positively correlated with the expression of AR, including both AR-FL (full-length) and AR-V7 (variant 7), which is mainly mediated by a bromodomain containing protein 4 (BRD4) -mediated pathway. Furthermore, knockdown of HAT1 can re-sensitize the response of CRPC cells to ENZ treatment in cells and mouse models. In addition, ascorbate was observed to decrease AR expression through downregulation of HAT1 expression. Collectively, our findings reveal a novel AR signaling regulation pathway in PCa and CRPC and suggest that HAT1 serves as a critical oncoprotein and an ideal target for the treatment of ENZ resistance in CRPC patients.

Apalutamide-induced severe interstitial lung disease: A report of two cases from Japan

Apalutamide, a competitive inhibitor of the androgen receptor, is being increasingly used for the treatment of prostate cancer. There have been few reports of interstitial lung disease in clinical trials of apalutamide. However, two cases of apalutamide-induced interstitial lung disease with respiratory failure in Japanese males, who were successfully treated with high-dose corticosteroids, are presented here. These cases suggest that clinicians should be alert to the potentially life-threatening risk of pulmonary toxicity associated with apalutamide treatment.

A drug safety evaluation of enzalutamide to treat advanced prostate cancer

INTRODUCTION

Prostate cancer (PC) is the most common cancer in North American men. Advanced PC is incurable. The androgen receptor antagonist enzalutamide is used to manage advanced PC, often over a period of months or years; it is therefore important to evaluate the safety profile of enzalutamide.

AREAS COVERED

This literature review presents safety data from pivotal trials and real-world data studies of enzalutamide in patients with advanced PC, including metastatic hormone-sensitive prostate cancer (mHSPC), nonmetastatic castration-resistant prostate cancer (nmCRPC), and metastatic castration-resistant prostate cancer (mCRPC). A large body of evidence supports the maintenance or improvement in the health-related quality of life (HRQoL) afforded by enzalutamide treatment in patients with mHSPC, nmCRPC, or chemotherapy-naïve mCRPC, as well as improvement in the HRQoL in patients with later-stage symptomatic mCRPC. Efficacy data from clinical trials are also briefly discussed.

EXPERT OPINION

We aim to provide clinicians with a better understanding of how to properly interpret enzalutamide clinical trial safety data. This knowledge may help clinicians guide their patients with PC to achieve optimal clinical benefit from enzalutamide therapy, and to properly manage their patients to mitigate any potential risk.

Recent Development and Future Prospects of Molecular Targeted Therapy in Prostate Cancer

Prostate cancer (PC) is a rapidly increasing ailment worldwide. The previous decade has observed a rapid advancement in PC therapies that was evident from the number of FDA approvals during this phase. Androgen deprivation therapies (ADT) have traditionally remained a mainstay for the management of PCs, but the past decade has experienced the emergence of newer classes of drugs that can be used with or without the administration of ADT. FDA approved poly (ADP-ribose) polymerase inhibitors (PARPi), such as olaparib and rucaparib, after successful clinical trials against gene-mutated metastatic castration-resistant prostate cancer. Furthermore, drugs like apalutamide, darolutamide, and enzalutamide with an androgen-targeted mechanism of action have manifested superior results in non-metastatic castration-resistant prostate cancer (nmCRPC), metastatic castration-sensitive prostate cancer (mCSPC), and metastatic castration-resistant prostate cancer (mCRPC), respectively, with or without previously administered docetaxel. Relugolix, an oral gonadotropin-releasing hormone antagonist, and a combination of abiraterone acetate plus prednisone were also approved by FDA after a successful trial in advanced PC and mCRPC, respectively. This review aims to analyze the FDA-approved agents in PC during the last decade and provide a summary of their clinical trials. It also presents an overview of the ongoing progress of prospective molecules still under trial.