Targeting the androgen receptor signaling pathway in advanced prostate cancer

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PURPOSE

This article summarizes current androgen receptor (AR)-directed therapies that have received regulatory approval for the treatment of advanced prostate adenocarcinoma (herein referred to as prostate cancer, PC).

SUMMARY

PC is an androgen-dependent malignancy in which ligands including testosterone and dihydrotestosterone bind to AR, initiating androgen-AR complex translocation to the nucleus followed by AR-mediated transcription of target genes. Androgen deprivation therapy (ADT), including gonadotropin hormone-releasing hormone (GnRH) agonists with or without AR antagonists (antiandrogens), GnRH antagonists, or bilateral orchiectomy, forms the backbone of treatment for patients with metastatic castration-naive PC and/or castration-resistant PC (CRPC). ADT is also an option for high-risk, early-stage PC after prostatectomy and/or radiation. While ADT is often very effective as initial therapy, resistance ultimately develops despite suppression of gonadal and/or adrenal androgens, leading to CRCPC, which is characterized by mechanisms such as reactivation of the AR signaling pathway, AR overexpression, and gene mutations in the ligand-binding domain of AR that lead to disease progression, resulting in increased symptom burden and ultimately death. However, disease in patients with CRPC is still dependent on androgen signaling, and these patients continue on ADT to maintain a castrate level of serum testosterone. Novel hormonal therapies including agents that target AR directly (eg, AR antagonists) are often added to ADT in this setting. Targeting the AR signaling pathway led to the development of second-generation AR antagonists, examples of which include enzalutamide, apalutamide, and darolutamide. These agents do not exhibit partial agonism or possess a higher affinity for AR and are not postulated to improve survival outcomes relative to their first-generation counterparts for patients with CRPC. Lastly, the emergence of ADT, including second-generation AR antagonists, has led to the development of supportive care for treatment-related adverse effects.

CONCLUSION

Major advances have been made in targeting the AR signaling pathway in patients with advanced PC. Further studies are warranted to identify the optimal sequencing of therapies to maximize treatment benefit. Mitigation of treatment-related adverse effects presents new opportunities to advance clinical pharmacy practice.

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.

Combination therapy with novel androgen receptor antagonists and statin for castration-resistant prostate cancer

BACKGROUND

One of the growth mechanisms of castration-resistant prostate cancer (CRPC) is de novo androgen synthesis from intracellular cholesterol, and statins may be able to inhibit this mechanism. In addition, statins have been reported to suppress the expression of androgen receptors (ARs) in prostate cancer cell lines. In this study, we investigated a combination therapy of novel AR antagonists and statin, simvastatin, for CRPC.

METHODS

LNCaP, 22Rv1, and PC-3 human prostate cancer cell lines were used. We developed androgen-independent LNCaP cells (LNCaP-LA). Microarray analysis was performed, followed by pathway analysis, and mRNA and protein expression was evaluated by quantitative real-time polymerase chain reaction and Western blot analysis, respectively. Cell viability was determined by MTS assay and cell counts. All evaluations were performed on cells treated with simvastatin and with or without AR antagonists (enzalutamide, apalutamide, and darolutamide).

RESULTS

The combination of darolutamide and simvastatin most significantly suppressed proliferation in LNCaP-LA and 22Rv1 cells. In a 22Rv1-derived mouse xenograft model, the combination of darolutamide and simvastatin enhanced the inhibition of cell proliferation. In LNCaP-LA cells, the combination of darolutamide and simvastatin led to reduction in the mRNA expression of the androgen-stimulated genes, KLK2 and PSA; however, this reduction in expression did not occur in 22Rv1 cells. The microarray data and pathway analyses showed that the number of differentially expressed genes in the darolutamide and simvastatin-treated 22Rv1 cells was the highest in the pathway termed "role of cell cycle." Consequently, we focused our efforts on the cell cycle regulator polo-like kinase 1 (PLK1), cyclin-dependent kinase 2 (CDK2), and cell cycle division 25C (CDC25C). In 22Rv1 cells, the combination of darolutamide and simvastatin suppressed the mRNA and protein expression of these three genes. In addition, in PC-3 cells (which lack AR expression), the combination of simvastatin and darolutamide enhanced the suppression of cell proliferation and expression of these genes.

CONCLUSIONS

Simvastatin alters the expression of many genes involved in the cell cycle in CRPC cells. Thus, the combination of novel AR antagonists (darolutamide) and simvastatin can potentially affect CRPC growth through both androgen-dependent and androgen-independent mechanisms.

Treatment Landscape of Nonmetastatic Castration-Resistant Prostate Cancer: A Window of Opportunity

The treatment for nonmetastatic castration-resistant prostate cancer (nmCRPC) is a highly unmet medical need. The classic treatment approach for these patients-androgen deprivation therapy (ADT) alone-until metastatic progression is now considered suboptimal. Several randomized phase III clinical trials have demonstrated significant clinical benefits-including significantly better overall survival (OS)-for treatments that combine ADT with apalutamide, enzalutamide, and darolutamide. As a result, these approaches are now included in treatment guidelines and are considered a standard of care. In the present article, we discuss the changing landscape of the management of patients with nmCRPC.

Risk of cardiovascular toxicities and hypertension in nonmetastatic castration-resistant prostate cancer patients treated with novel hormonal agents: a systematic review and meta-analysis

Background: With hormonal agents quickly expanding as novel therapeutic options in nonmetastatic castration-resistant prostate cancer (nmCRPC), the toxicity profile of enzalutamide, apalutamide, and darolutamide should be kept in mind.Methods: We performed an updated meta-analysis with the aim to analyze the risk of treatment-related cardiovascular (CV) events, any grade, and grade 3-4 (G3-4) hypertension in nmCRPC patients treated with enzalutamide, apalutamide, and darolutamide plus androgen deprivation therapy (ADT) versus ADT plus placebo in randomized controlled trials (RCTs). Results were compared by calculating Relative Risk (RR) with 95% confidence intervals (CIs); RRs were combined with Mantel-Haenszel method.Results: Three RCTs involving 4110 patients were available for the meta-analysis. According to our results, the addition of novel hormonal agents was associated with a significantly increased risk of CV events (RR = 1.71; 95% CI 1.29-2.27) and G3-4 hypertension (RR = 1.53; 95% CI 1.19-1.97). In addition, a trend toward a higher risk of any grade hypertension was reported in the experimental arm.Conclusions: The use of enzalutamide, apalutamide, and darolutamide in nmCRPC patients implies a careful benefit-risk assessment. Real-world, large-cohort studies are warranted to confirm the findings of our meta-analysis.

Androgen receptor signaling inhibitors: post-chemotherapy, pre-chemotherapy and now in castration-sensitive prostate cancer

Based on pioneering work by Huggins, Hodges and others, hormonal therapies have been established as an effective approach for advanced prostate cancer (PC) for the past eight decades. However, it quickly became evident that androgen deprivation therapy (ADT) via surgical or medical castration accomplishes inadequate inhibition of the androgen receptor (AR) axis, with clinical resistance inevitably emerging due to adrenal and intratumoral sources of androgens and other mechanisms. Early efforts to augment ADT by adding adrenal-targeting agents (aminoglutethimide, ketoconazole) or AR antagonists (flutamide, bicalutamide, nilutamide, cyproterone) failed to achieve overall survival (OS) benefits, although they did exhibit some evidence of limited clinical activity. More recently, four new androgen receptor signaling inhibitors (ARSIs) successfully entered clinical practice. Specifically, the CYP17 inhibitor abiraterone acetate and the second generation AR antagonists (enzalutamide, apalutamide and darolutamide) achieved OS benefits for PC patients, confirmed the importance of reactivated AR signaling in castration-resistant PC and validated important concepts that had been proposed in the field several decades ago but had remained so far unproven, including adrenal-targeted therapy and combined androgen blockade. The past decade has seen steady advances toward more comprehensive AR axis targeting. Now the question is raised whether we have accomplished the maximum AR axis inhibition possible or there is still room for improvement. This review, marking the 80-year anniversary of ADT and 10-year anniversary of successful ARSIs, examines their current clinical use and discusses future directions, in particular combination regimens, to maximize their efficacy, delay emergence of resistance and improve patient outcomes.

Evaluation of Darolutamide (ODM201) Efficiency on Androgen Receptor Mutants Reported to Date in Prostate Cancer Patients

Resistance to drug treatments is common in prostate cancer (PCa), and the gain-of-function mutations in human androgen receptor (AR) represent one of the most dominant drivers of progression to resistance to AR pathway inhibitors (ARPI). Previously, we evaluated the in vitro response of 24 AR mutations, identified in men with castration-resistant PCa, to five AR antagonists. In the current work, we evaluated 44 additional PCa-associated AR mutants, reported in the literature, and thus expanded the study of the effect of darolutamide to a total of 68 AR mutants. Unlike other AR antagonists, we demonstrate that darolutamide exhibits consistent efficiency against all characterized gain-of-function mutations in a full-length AR. Additionally, the response of the AR mutants to clinically used bicalutamide and enzalutamide, as well as to major endogenous steroids (DHT, estradiol, progesterone and hydrocortisone), was also investigated. As genomic profiling of PCa patients becomes increasingly feasible, the developed "AR functional encyclopedia" could provide decision-makers with a tool to guide the treatment choice for PCa patients based on their AR mutation status.

Novel Treatment Strategy Using Second-Generation Androgen Receptor Inhibitors for Non-Metastatic Castration-Resistant Prostate Cancer

Non-metastatic castration-resistant prostate cancer (nmCRPC) is defined by a progressively rising prostate-specific antigen level, despite a castrate level of testosterone, in the absence of obvious radiologic evidence of metastatic disease on conventional imaging modalities. As a significant proportion of patients with nmCRPC develop metastatic diseases, the therapeutic goals of physicians for these patients are to delay metastasis development, preserve quality of life, and increase overall survival (OS). Since 2018, the treatment of nmCRPC has changed dramatically with the introduction of second-generation androgen receptor inhibitors, such as enzalutamide (ENZA), apalutamide (APA), and darolutamide (DARO). These drugs demonstrated substantial improvements in metastasis-free survival (MFS) and OS in phase III randomized clinical trials. In addition, these drugs have an excellent safety profile, preserve quality of life, and can delay disease-related symptoms. A recently published indirect meta-analysis reported that APA and ENZA showed better findings in MFS and that DARO had relatively fewer adverse effects. However, in the absence of a direct comparison, careful interpretation is required. Thus, APA, ENZA, and DARO should be considered the new standard drugs for treating nmCRPC.

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.

Darolutamide as a Second-Generation Androgen Receptor Inhibitor in the Treatment of Prostate Cancer

Prostate cancer (PC) is known as the most frequent cancer among men in the world. Androgen Deprivation Therapy (ADT) is one of the initial treatment approaches in the PC therapy and various drugs can be used in routine Hormonal therapy for PC therapy. Nevertheless, PC cells can survive and continue their growth via different mechanisms which lead to their resistance to common treatments i.e., Enzalutamide. olutamide (ODM-201) is a second-generation androgen receptor (AR) inhibitor with a new chemical structure and has a high affinity to the AR. Darolutamide does not cross the blood-brain barrier and for this reason, reduces the possibility of seizures. Darolutamide can also inhibit the transcriptional activity of several AR mutant variants (F877L, F877L/T878A, and H875Y/T878A), which are Enzalutamide resistant. In this review, we reviewed the results of different studies: in vitro, animal model and phase 1, 2 and 3 clinical trials (ARADES, ARAFOR and ARAMIS). We shall discuss worldwide phase 2 and 3 clinical trials (ARASENS and ODENZA) that are in progress, in order to demonstrate the advantages of Darolutamide consumption in different groups of patients. Darolutamide has shown high potential in inhibiting the growth of MR49F (Enzalutamide resistant PC cells) and VCaP (Castration-resistant PC cells) cell lines and transcriptional activities of AR. Fewer doses of Darolutamide are needed compared to Enzalutamide. The drug had significant anti-tumor activity and no effect on serum testosterone levels in animal models. Darolutamide demonstrates its safety and efficacy in different studies and was well tolerated nearly in all of the patients.

Indirect Comparison of Darolutamide versus Apalutamide and Enzalutamide for Nonmetastatic Castration-Resistant Prostate Cancer

PURPOSE

No published head-to-head randomized trials have compared the safety and efficacy of darolutamide vs apalutamide or enzalutamide in nonmetastatic castration-resistant prostate cancer. This study compares prespecified adverse events and metastasis-free survival associated with darolutamide vs apalutamide, and darolutamide vs enzalutamide, via matching-adjusted indirect comparisons.

MATERIALS AND METHODS

Individual patient data from the phase III ARAMIS trial (N_PLACEBO=553; N_DAROLUTAMIDE=943) were selected and reweighted to match the inclusion criteria and baseline characteristics published for the phase III SPARTAN (N_PLACEBO=401; N_APALUTAMIDE=806) and PROSPER (N_PLACEBO=468; N_ENZALUTAMIDE=933) trials. Only baseline factors consistently reported across trials were included as matching covariates. Both indirect comparisons matched on age, prostate specific antigen level and doubling time, Eastern Cooperative Oncology Group performance status, Gleason score, and bone-sparing agent use. Darolutamide vs apalutamide also matched on prior surgery and darolutamide vs enzalutamide also matched on region. Risk differences and odds ratios were calculated for adverse events and hazard ratios for metastasis-free survival.

RESULTS

No differences in metastasis-free survival hazard ratios were found after matching in either comparison. However, fall, fracture and rash rates were statistically significantly lower in favor of darolutamide vs apalutamide. Fall, dizziness, mental impairment, fatigue and severe fatigue rates were statistically significantly lower in favor of darolutamide vs enzalutamide.

CONCLUSIONS

While metastasis-free survival did not differ across drugs in these cross-trial indirect comparisons, darolutamide showed a favorable safety and tolerability profile in prespecified adverse events vs apalutamide and enzalutamide. Consideration of these adverse events is important in clinical decision-making and treatment selection in nonmetastatic castration-resistant prostate cancer.

Darolutamide and survival in nonmetastatic, castration-resistant prostate cancer: a patient perspective of the ARAMIS trial

This is a summary of a publication about the ARAMIS (Androgen Receptor Antagonizing Agent for Metastasis-free Survival) trial, which was published in the New England Journal of Medicine in September 2020. The trial was in adult participants with nonmetastatic, castration-resistant prostate cancer (nmCRPC) who received a trial treatment called darolutamide (brand name Nubeqa®). Darolutamide is currently available as an oral treatment for adults with nmCRPC. The ARAMIS trial looked at darolutamide taken by mouth in 1509 participants from 36 countries with nmCRPC (prostate cancer that has not spread to other parts of the body and no longer responds adequately to initial hormone therapy). The trial showed that darolutamide in addition to hormone therapy increased the length of time that the trial participants were still alive for and lowered the risk of death by 31% compared with placebo (sugar pill) and hormone therapy. The participants who received darolutamide and hormone therapy also had longer time to worsening pain, needing chemotherapy, and having cancer-related bone fractures or symptoms related to cancer-related bone fractures compared with those who received placebo and hormone therapy during the trial. In general, the percentage of participants who experienced medical problems (referred to as adverse events) was similar between those who received darolutamide and those who received placebo, in addition to hormone therapy. This summary also includes insights and perspectives from a participant who was in the ARAMIS trial and from a prostate cancer patient advocate. To read the full Plain Language Summary of this article, click on the View Article button above and download the PDF. Clinical Trial Registration: NCT02200614 (ClinicalTrials.gov).

Apalutamide, darolutamide and enzalutamide in nonmetastatic castration-resistant prostate cancer: a meta-analysis

Aim: Comparison of the efficacy/safety/health-related quality of life of apalutamide, enzalutamide and darolutamide in Phase III clinical trials involving patients with nonmetastatic castration-resistant prostate cancer was performed. Materials & methods: Relevant studies were identified by searching PubMed as well as conference abstracts reporting updated overall survival. Three pivotal trials were identified, SPARTAN (apalutamide), PROSPER (enzalutamide) and ARAMIS (darolutamide), and form the basis of this analysis. Results: All three drugs significantly prolonged metastasis-free survival, prostate-specific antigen response and overall survival versus placebo, and were generally well tolerated. Conclusion: Drug selection will likely be influenced by tolerability/safety and other factors, such as the propensity for drug-drug interactions and the presence of comorbidities, that affect the risk-benefit balance in individual patients.

Next-generation androgen receptor inhibitors in non-metastatic castration-resistant prostate cancer

Until recently, continuing androgen deprivation therapy (ADT) and closely monitoring patients until evolution towards metastatic castration-resistant prostate cancer (CRPC) were recommended in men with non-metastatic CRPC (nmCRPC). Because delaying the development of metastases and symptoms in these patients is a major issue, several trials have investigated next-generation androgen receptor (AR) axis inhibitors such as apalutamide, darolutamide, and enzalutamide in this setting. This review summarizes the recent advances in the management of nmCRPC, highlighting the favourable impact of next-generation AR inhibitors on metastases-free survival, overall survival and other clinically meaningful endpoints.

Novel methodology to perform incurred sample reanalysis on dried blood spot cards: Experimental data using darolutamide and filgotinib

Different options on performing incurred sample reanalysis (ISR) on dried blood spot (DBS) cards were investigated using drugs belonging to various therapeutic areas: (a) darolutamide (to treat prostate cancer) and (b) filgotinib (to treat rheumatoid arthritis). The proposed novel methodology included the generation of half-DBS and quarter-DBS discs after initial blood collection using the full-DBS discs. Accordingly, blood collection via DBS was performed in male BALB/c mice following intravenous and oral dosing of darolutamide; in male Sprague Dawley rats following intravenous and oral dosing of filgotinib. The ISR data generated from the full-DBS disc, half-DBS disc and quarter-DBS disc were compared for the assessment of the proposed methodology. Quantification of darolutamide and filgotinib was accomplished using liquid chromatography-electrospray ionization/tandem mass spectrometry methods. Darolutamide and filgotinib ISR samples, which were collected and prepared using full-, half- and quarter-DBS discs, met the acceptance criteria for ISR analysis. In conclusion, this is the first report showing a viable tool for the performance of ISR on DBS cards. The use of quarter- or half-DBS discs would aid in not only ISR but also in long-term storage experiments of analytes because it would avoid the need for additional blood sampling in patients.

Evaluation of Cognitive Function in Trials Testing New-Generation Hormonal Therapy in Patients with Prostate Cancer: A Systematic Review

Simple Summary

In patients with prostate cancer, the use of new-generation hormonal therapy, added to androgen deprivation therapy, requires careful evaluation of cognitive function. The aim of this systematic review is to describe the evidence about cognitive function in randomized trials testing new-generation hormonal therapy (abiraterone, enzalutamide, apalutamide, darolutamide). For each trial, we assessed the availability of both investigator-assessed cognitive impairment and disorders and patient-reported evaluation of cognitive function. Out of 19 trials, the investigator-based evaluation of cognitive impairment was available in seven (36.8%), while patient-reported evaluation of cognitive function results was presented only in one trial (5.3%). This analysis shows that, despite cognitive deterioration could be relevant in patients with prostate cancer, clinical development of new-generation hormonal drugs has not included a systematic evaluation of cognitive function.

Abstract

In patients with prostate cancer, earlier use and longer duration of new-generation hormonal therapy (NGHT), added to androgen deprivation therapy, requires careful evaluation of cognitive function. The aim of this systematic review is to describe the evidence about cognitive function in all the randomized trials (RCTs) testing NGHT (abiraterone, enzalutamide, apalutamide, darolutamide). We assessed the availability of both investigator-assessed cognitive impairment and disorders and patient-reported evaluation of cognitive function. Nineteen RCTs (17,617 patients) were included. The investigator-based evaluation of cognitive impairment was available in seven RCTs (36.8%). In total, 19/19 RCTs (100%) included patient-reported outcomes (PROs) collection, but PRO tools adopted allowed evaluation of cognitive function in two RCTs (10.5%). Among them, PRO-based cognitive function results were presented only in one RCT (5.3%): in ENZAMET, mean changes from baseline were worse with enzalutamide than with placebo, but deterioration-free survival favored enzalutamide. Despite cognitive deterioration could be relevant, clinical development of NGHT has not included a systematic evaluation of cognitive function. Assessment by investigators is at risk of underreporting, and commonly used PROs do not allow proper cognitive function analysis. Furthermore, the methodology of analysis can jeopardize the interpretation of results. Although direct comparisons are scanty, there could be differences between different NGHTs.

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.

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.

Non-metastatic castration-resistant prostate cancer: current status and future directions

INTRODUCTION

The emergence of novel hormonal therapies and the increase availability of sensitive next-generation imaging techniques has significantly changed the management of recurrent prostate cancer.

AREAS COVERED

In this review, we summarize the definition, diagnosis, treatment, and ongoing clinical trials in non-metastatic castration resistant prostate cancer (M0CRPC). We have also discussed the role of newer imaging modalities in the detection of advanced prostate cancer.

EXPERT OPINION

M0CRPC is a disease state in prostate cancer when serologic progression (PSA only disease) occurs despite castrated levels of testosterone and imaging shows no evidence of metastasis. With the availability of next-generation imaging, more patients are migrating from M0CRPC to mCRPC space. This stage migration impacts the treatment options currently available in clinical practice and requires the integration of novel imaging in prospective studies moving forward. Until that data become available men with M0CRPC should be considered for therapy with any of these three novel oral AR inhibitors, with a positive impact in metastasis-free and overall survival. Treatment selection should be based on Quality of Life, side effects, and drug-drug interactions.

Second-Generation Androgen Receptor Antagonists as Hormonal Therapeutics for Three Forms of Prostate Cancer

Enzalutamide is the first second-generation nonsteroidal androgen receptor (AR) antagonist with a strong binding affinity to AR. Most significantly, enzalutamide can prolong not only overall survival time and metastatic free survival time for patients with lethal castration-resistant prostate cancer (CRPC), but also castration-resistant free survival time for patients with castration-sensitive prostate cancer (CSPC). Enzalutamide has thus been approved by the US Food and Drug Administration (FDA) for the treatment of both metastatic (in 2012) and non-metastatic (in 2018) CRPC, as well as CSPC (2019). This is an inspiring drug discovery story created by an amazing interdisciplinary collaboration. Equally important, the successful clinical use of enzalutamide proves the notion that the second-generation AR antagonists can serve as hormonal therapeutics for three forms of advanced prostate cancer. This has been further verified by the recent FDA approval of the other two second-generation AR antagonists, apalutamide and darolutamide, for the treatment of prostate cancer. This review focuses on the rational design and discovery of these three second-generation AR antagonists, and then highlights their syntheses, clinical studies, and use. Strategies to overcome the resistance to the second-generation AR antagonists are also reviewed.

Darolutamide For Castration-Resistant Prostate Cancer

The treatment landscape of advanced prostate cancer continues to evolve rapidly, with newer and more active drugs being used in earlier phases of the disease based on improved overall survival. After adoption of docetaxel for metastatic castration-sensitive disease, large trials with next-generation androgen receptor-signaling inhibitors (abiraterone, enzalutamide and apalutamide) have demonstrate significant improvements in survival and important secondary endpoints. For non-metastatic castration-resistant prostate cancer, recent phase III placebo-controlled trials with enzalutamide, apalutamide and darolutamide all demonstrated benefits in improving metastasis-free survival. This review aims to summarize the clinical development of darolutamide, a novel next-generation androgen receptor antagonist, including preclinical data, clinical studies and the potential of darolutamide for the treatment of advanced prostate cancer. To date, darolutamide efficacy and tolerability has been demonstrated in the ARAMIS trial, which demonstrated an improvement in metastasis-free survival compared to placebo for non-metastatic castration-resistant prostate cancer patients with a rapid PSA doubling time. Ongoing studies will further evaluate the role of darolutamide in metastatic castration-sensitive prostate cancer in combination with docetaxel (ARASENS trial) and also in other stages of the disease.

Combining prostate cancer radiotherapy with therapies targeting the androgen receptor axis

Background

Prostate cancer (pca) is the most common non-dermatologic cancer and the 3rd leading cause of male cancer mortality in Canada. In patients with high-risk localized or recurrent pca, management typically includes the combination of long-term androgen deprivation therapy (adt) and radiotherapy (rt). New androgen-receptor-axis targeted therapies (arats), which await validation, offer an option to intensify therapy.

Methods

In this narrative review, we report the relevant history that has supported combining adt with rt. The literature in PubMed was searched for studies involving pca and novel arats (abiraterone acetate, enzalutamide, apalutamide, darolutamide) published between 1995 and 2019. Literature discussing clinical trials in which those modalities were combined was extracted and synthesized into a combined molecular and clinical discussion. Potential treatment intensification mechanisms and rationales are explored.

Results

Early results from three phase i/ii trials demonstrated that concurrent abiraterone acetate, adt, and rt is safe, improves the extent of chemical castration, and is associated with limited treatment failures. A single in vitro study implies synergy for radiosensitization beyond that facilitated by conventional adt. Studies investigating the combination of other arats with rt are under way, including multiple phase iii trials, but short-term results are not yet available.

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.

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.