Practical Guidance on the Role of Corticosteroids in the Treatment of Metastatic Castration-resistant Prostate Cancer

The rates of septicemia in older adults with prostate cancer treated with abiraterone or enzalutamide: A population-based study

INTRODUCTION

Prostate cancer (PCa) is the most common non-cutaneous tumor among American men. Androgen receptor signaling inhibitors such as abiraterone and enzalutamide have been approved for similar disease states among patients with advanced PCa. Existing data suggest using steroids is associated with an increased risk of infection. Because abiraterone is usually prescribed with prednisone, we sought to compare the risk of septicemia in patients using abiraterone vs. enzalutamide.

MATERIALS AND METHODS

We utilized the SEER-Medicare-linked data and used negative binomial regression models to compare the changes in the rates of septicemia-related hospitalizations six months pre- and post-abiraterone and enzalutamide initiation.

RESULTS

We found that the incidence of septicemia-related hospitalizations increased 2.77 fold within six months of initiating abiraterone (incidence rate ratio [IRR]: 2.77, 95% confidence interval [CI]: 2.17-3.53) 1.97 fold within six months of starting enzalutamide (IRR: 1.97, 95% CI: 1.43-2.72). However, the difference in the changes did not reach statistical significance (interaction IRR: 0.71, 95% CI: 0.48-1.06).

DISCUSSION

The findings suggest that both abiraterone and enzalutamide are associated with an increased risk of septicemia-related hospitalizations. However, the difference in the increase of septicemia risk following the two treatments did not reach statistical significance. Further studies are warranted to understand the mechanisms at play.

Microbiome and Prostate Cancer: Emerging Diagnostic and Therapeutic Opportunities

This review systematically addresses the correlation between the microbiome and prostate cancer and explores its diagnostic and therapeutic implications. Recent research has indicated an association between the urinary and gut microbiome composition and prostate cancer incidence and progression. Specifically, the urinary microbiome is a potential non-invasive biomarker for early detection and risk evaluation, with altered microbial profiles in prostate cancer patients. This represents an advancement in non-invasive diagnostic approaches to prostate cancer. The role of the gut microbiome in the efficacy of various cancer therapies has recently gained attention. Gut microbiota variations can affect the metabolism and effectiveness of standard treatment modalities, including chemotherapy, immunotherapy, and hormone therapy. This review explores the potential of gut microbiome modification through dietary interventions, prebiotics, probiotics, and fecal microbiota transplantation for improving the treatment response and mitigating adverse effects. Moreover, this review discusses the potential of microbiome profiling for patient stratification and personalized treatment strategies. While the current research identifies the pivotal role of the microbiome in prostate cancer, it also highlights the necessity for further investigations to fully understand these complex interactions and their practical applications in improving patient outcomes in prostate cancer management.

Drug resistance in metastatic castration-resistant prostate cancer: an update on the status quo

Prostate cancer (PCa) is a leading cause of cancer-related morbidity and mortality in men globally. Despite improvements in the diagnosis and treatment of PCa, a significant proportion of patients with high-risk localized disease and all patients with advanced disease at diagnosis will experience progression to metastatic castration-resistant prostate cancer (mCRPC). Multiple drugs are now approved as the standard of care treatments for patients with mCRPC that have been shown to prolong survival. Although the majority of patients will respond initially, primary and secondary resistance to these therapies make mCRPC an incurable disease. Several molecular mechanisms underlie the development of mCRPC, with the androgen receptor (AR) axis being the main driver as well as the key drug target. Understanding resistance mechanisms is crucial for discovering novel therapeutic strategies to delay or reverse the progression of the disease. In this review, we address the diverse mechanisms of drug resistance in mCRPC. In addition, we shed light on emerging targeted therapies currently being tested in clinical trials with promising potential to overcome mCRPC-drug resistance.

Fatigue, health-related quality-of-life and metabolic changes in men treated with enzalutamide or abiraterone acetate plus prednisone for metastatic castration-resistant prostate cancer: A randomised clinical trial (HEAT)

INTRODUCTION

Enzalutamide and abiraterone acetate plus prednisone (AAP) have similar efficacy in metastatic castration-resistant prostate cancer (mCRPC). Herein, we compare fatigue, health-related quality-of-life (HRQoL) and metabolic changes in men with mCRPC treated with enzalutamide and AAP.

MATERIALS AND METHODS

In this single-centre, open-labelled, phase IV trial, patients with metastatic prostate cancer progressing on androgen deprivation therapy were randomly assigned to enzalutamide (160 mg daily) or AAP (1000 mg abiraterone acetate and 10 mg prednisone daily) as first-line mCRPC treatment. The primary outcome was the difference in changed fatigue (Functional Assessment of Chronic Illness Therapy-Fatigue questionnaire). The secondary outcomes were differences in changed HRQoL (Functional Assessment of Cancer Therapy-Prostate questionnaire), body composition, weight, glucose homeostasis, lipid profile and blood pressure. All outcomes were assessed at baseline and at 12-week follow-up.

TRIAL REGISTRATION

clinicaltrialsregister.eu (2017-000099-27).

RESULTS

170 patients were randomised (1:1) to enzalutamide or AAP. The primary outcome was positive with a clinically meaningful difference in fatigue, favouring AAP (3.4 points, 95% CI 1.2; 5.6, P = 0.003). The group difference in changed HRQoL did not reach clinical significance. The most important metabolic finding was a higher increase in glycated haemoglobin (HbA1c) for AAP than enzalutamide (3.4 mmol/mol, 95% CI 2.1; 4.8, P = 0.001). Eight patients developed type 2 diabetes (T2D) in the AAP group and none in the enzalutamide group. No treatment-related serious adverse event was observed.

CONCLUSIONS

AAP resulted in less fatigue than enzalutamide in a randomised setting. This was at the expense of a higher HbA1c increase and incidence of T2D.

Quality of life in men with metastatic castration-resistant prostate cancer treated with enzalutamide or abiraterone: a systematic review and meta-analysis

BACKGROUND

Enzalutamide and abiraterone acetate plus prednisone (AAP) have similar efficacy in metastatic castration-resistant prostate cancer (mCRPC), but different mechanisms of action. The aim was to compare patient-reported health-related quality of life (HRQoL) in men treated with enzalutamide vs AAP for mCRPC.

METHODS

We systematically reviewed the literature in June 2020 according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) recommendations. Patient-reported outcomes (PROs) until the last follow-up were summarised in a narrative synthesis. Short-term changes (12 weeks) in HRQoL, measured by the Functional Assessment of Cancer Therapy-Prostate total score (FACT-P), were compared between treatment groups and were analysed for enzalutamide and AAP in separate meta-analyses. Higher FACT-P scores indicate better HRQoL.

RESULTS

Eight studies were included in the systematic review, four of which were randomised clinical trials (RCTs) eligible for the meta-analyses. The meta-analyses showed mean within-subject FACT-P changes from baseline to week 12 of -1.3 points (95% confidence interval [CI] -2.7; 0.1) for enzalutamide and 4.7 points (95% CI -0.1; 9.6) for AAP. One RCT and three non-randomised studies directly compared enzalutamide with AAP. The RCT showed better short-term HRQoL for AAP (6.8 FACT-P-points, 95% CI 1.7; 11.8) and better long-term HRQoL for AAP in men ≥75 years (7.35 FACT-P-points, 95% CI 2.59; 12.11). The non-randomised studies showed no difference in long-term HRQoL but had all a serious risk of bias. Limitations of the included studies include that the PRO in the included trials were inconsistently reported and that only one study defined the HRQoL measures in their published protocol.

CONCLUSIONS

AAP seems to be associated with better short-term HRQoL than enzalutamide. This difference was not apparent at longer follow-up, but the long-term studies had serious risks of bias.

Consensus on the Treatment and Follow-Up for Metastatic Castration-Resistant Prostate Cancer: A Report From the First Global Prostate Cancer Consensus Conference for Developing Countries (PCCCDC)

PURPOSE

To present a summary of the recommendations for the treatment and follow-up for metastatic castration-resistant prostate cancer (mCRPC) as acquired through a questionnaire administered to 99 physicians working in the field of prostate cancer in developing countries who attended the Prostate Cancer Consensus Conference for Developing Countries.

METHODS

A total of 106 questions out of more than 300 questions addressed the use of imaging in staging mCRPC, treatment recommendations across availability and response to prior drug treatments, appropriate drug treatments, and follow-up, and those same scenarios when limited resources needed to be considered. Responses were compiled and the percentages were presented by clinicians to support each response. Most questions had five to seven relevant options for response including abstain and/or unqualified to answer, or in the case of yes or no questions, the option to abstain was offered.

RESULTS

Most of the recommendations from this panel were in line with prior consensus, including the preference of a new antiandrogen for first-line therapy of mCRPC. Important aspects highlighted in the scenario of limited resources included the option of docetaxel as treatment preference as first-line treatment in several scenarios, docetaxel retreatment, consideration for reduced doses of abiraterone, and alternative schedules of an osteoclast-targeted therapy.

CONCLUSION

There was wide-ranging consensus in the treatment for men with mCRPC in both optimal and limited resource settings.

Practice review: Evidence-based quality use of corticosteroids in the palliative care of patients with advanced cancer

BACKGROUND

It would be unusual for a patient with advanced cancer not to be prescribed corticosteroids at some stage of their disease course for a variety of specific and non-specific indications.

AIM

The aim of this practice review was to provide a pragmatic overview of the evidence supporting current practice and to identify areas in which further research is indicated.

DESIGN

A 'state-of-the-art' review approach was used to examine the evidence supporting the use of corticosteroids for the management of cancer-related complications and in symptom control, in the context of known risks and harms to inform quality use of this medicine. We developed 'Do', 'Do not', and 'Don't know' recommendations based on current literature and identified areas for future investigation and research.

DATA SOURCES

We searched MEDLINE, EMBASE and the Cochrane library from inception to 14th October 2020. Our initial search limited to reviews, reviews of reviews, randomised controlled trials (RCTs) and controlled trials was supplemented by supporting literature as appropriate.

RESULTS

Evidence to support common practice in the use of corticosteroids is lacking for most indications. This is in the context of strong evidence for the potential for significant toxicity and poor quality use of medicine.

CONCLUSION

Guidelines recommending the widespread use of corticosteroids should acknowledge the poor evidence base supporting much current dogma. Quality research is essential not only to define the role of corticosteroids in this context but to ensure good prescribing practice.

Discovery of A031 as effective proteolysis targeting chimera (PROTAC) androgen receptor (AR) degrader for the treatment of prostate cancer

Androgen receptor (AR) is an effective therapeutic target for the treatment of prostate cancer. We report herein the design, synthesis, and biological evaluation of highly effective proteolysis targeting chimeras (PROTAC) androgen receptor (AR) degraders, such as compound A031. It could induce the degradation of AR protein in VCaP cell lines in a time-dependent manner, achieving the IC 50 value of less than 0.25 μM. The A031 is 5 times less toxic than EZLA and works with an appropriate half-life (t 1/2) or clearance rate (Cl). Also, it has a significant inhibitory effect on tumor growth in zebrafish transplanted with human prostate cancer (VCaP). Therefore, A031 provides a further idea of developing novel drugs for prostate cancer.

Economic Outcomes in Patients with Chemotherapy-Naïve Metastatic Castration-Resistant Prostate Cancer Treated with Enzalutamide or Abiraterone Acetate Plus Prednisone

Introduction

Prostate cancer (PC) is the second leading cause of cancer death among US men and accounts for considerable healthcare expenditures. We evaluated economic outcomes in men with chemotherapy-naïve metastatic castration-resistant PC (mCRPC) treated with enzalutamide or abiraterone acetate plus prednisone (abiraterone).

Methods

We performed a retrospective analysis on 3174 men (18 years or older) utilizing the Veterans Health Administration (VHA) database from 1 April 2014 to 31 March 2018. Men with mCRPC were included if they had at least one pharmacy claim for enzalutamide or abiraterone (first claim date = index date) following surgical or medical castration, had no chemotherapy treatment within 12 months prior to the index date, and had continuous VHA enrollment for at least 12 months pre- and post-index date. Men were followed until death, disenrollment, or end of study and were 1:1 propensity score matched (PSM). All-cause and PC-related resource use and costs per patient per month (PPPM) in the 12 months post index were compared between matched cohorts.

Results

We identified 1229 men with mCRPC prescribed enzalutamide and 1945 prescribed abiraterone with mean ages of 74 and 73 years, respectively. After PSM, each cohort had 1160 patients. The enzalutamide cohort had fewer all-cause (2.51 vs 2.86; p < 0.0001) and PC-related outpatient visits (0.86 vs 1.03; p < 0.0001), with corresponding lower all-cause ($2588 vs $3115; p < 0.0001) and PC-related ($1356 vs $1775; p < 0.0001) PPPM outpatient costs compared with the abiraterone cohort. All-cause total costs (medical and pharmacy) PPPM ($8085 vs $9092; p = 0.0002) and PC-related total costs PPPM ($6321 vs $7280; p < 0.0001) were significantly lower in the enzalutamide cohort compared with the abiraterone cohort.

Conclusions

Enzalutamide-treated men with chemotherapy-naïve mCRPC had significantly lower resource utilization and healthcare costs compared with abiraterone-treated men.

Electronic Supplementary Material

The online version of this article (10.1007/s12325-020-01260-x) contains supplementary material, which is available to authorized users.

Prostate cancer (PC) is the second leading cause of death among men with cancer in the USA. Healthcare costs associated with PC, including hospitalizations, outpatient visits, and medications prescribed to treat adverse effects, depend on the severity of the disease and intensity of treatment, but are generally very high. Enzalutamide and abiraterone acetate with prednisone (abiraterone) are both approved treatments for men with PC that does not respond to treatments that reduce the male hormone testosterone, known as castration-resistant PC (CRPC). These drugs are associated with varying treatment duration and different adverse effects, and therefore could result in differences in the use of healthcare resources and overall cost of treatment. Here we evaluated the healthcare resource utilization (HCRU), which was calculated as the average number of healthcare encounters, including inpatient stays, outpatient visits, and pharmacy visits, and length of inpatient stays, and treatment costs associated with use of enzalutamide or abiraterone by men with metastatic CRPC (mCRPC), who had not received prior chemotherapy in the Veterans Health Administration. We found that men with chemotherapy-naïve mCRPC treated with enzalutamide used less healthcare resources and incurred lower total healthcare costs than men treated with abiraterone. On average, all-cause total healthcare costs were $1007 per patient per month lower and PC-related total healthcare costs were $959 per patient per month lower for patients treated with enzalutamide than those treated with abiraterone. These results support the hypothesis that the long-term HCRU and costs of enzalutamide may be lower compared with abiraterone.

Adverse Events Associated with Cumulative Corticosteroid Use in Patients with Castration-Resistant Prostate Cancer: An Administrative Claims Analysis

INTRODUCTION

Corticosteroids are a mainstay treatment for castration-resistant prostate cancer (CRPC). Although corticosteroids have been associated with adverse events, long-term outcomes related to their sustained use have not been assessed in men with CRPC.

OBJECTIVE

This study evaluated the impact of cumulative corticosteroid exposure on the risk of developing specific adverse events in men with CRPC.

METHODS

Data were obtained from administrative claims databases. Adult chemotherapy-naïve men who initiated CRPC treatment following surgical or medical castration were selected. Patients were grouped into four cohorts based on cumulative corticosteroid dose: no exposure, low exposure (< 0.5 g), medium exposure (0.5-2.0 g), and high exposure (> 2.0 g). Time to each adverse event was assessed using Kaplan-Meier analyses and time-dependent Cox proportional hazard models, adjusting for baseline characteristics.

RESULTS

Overall, 9425 patients were included (no exposure, N = 6765; low exposure, N = 1660; medium exposure, N = 655; high exposure, N = 345). The mean age was 71-76 years across cohorts. During the study period, cumulative corticosteroid exposure was associated with a significantly higher risk of developing an infection [high vs. no exposure, adjusted hazard ratio (HR) 2.55; 95% confidence interval (CI) 2.27-2.85; p < 0.001 for trend], peptic ulcer (HR 1.91; 95% CI 1.39-2.64; p < 0.001), acute cardiovascular events (HR 1.62; 95% CI 1.43-1.83; p < 0.001), endocrine disorder (HR 1.61; 95% CI 1.34-1.94; p < 0.001), fracture (HR 1.59; 95% CI 1.37-1.86; p < 0.001), or mental health condition (HR 1.28; 95% CI 1.06-1.55; p = 0.014). Exposure to corticosteroids was associated with a more rapid onset of adverse events.

CONCLUSION

Patients with CRPC receiving corticosteroids had a higher risk of developing a wide range of adverse events than those not receiving them. The increased adverse event risk was observed after accounting, to the extent possible, for patients' overall disease severity.

Health Care Resource Utilization and Costs Associated with Corticosteroid Use in Patients with Castration-Resistant Prostate Cancer: An Administrative Claims Analysis

BACKGROUND

Corticosteroids are used in the management of castration-resistant prostate cancer (CRPC) to reduce tumor-related symptoms because of CRPC therapies. Since corticosteroids have been associated with a range of toxicities, their use may increase the economic burden sustained by patients with CRPC. However, the economic impact of using corticosteroids in patients with CRPC has not been well characterized.

OBJECTIVE

To assess the effect of previous corticosteroid use on health care resource utilization (HRU) and health care costs among men with CRPC.

METHODS

Using administrative claims data (2007-2016), adult chemotherapy-naive patients who initiated CRPC treatment following surgical or medical castration were identified. Based on the cumulative corticosteroid dose during the 12 months before CRPC treatment initiation, patients were grouped into 4 cohorts: no corticosteroid (0 gm), low corticosteroid (< 0.5 gm), medium corticosteroid (0.5-2.0 gm), and high corticosteroid (> 2.0 gm). All-cause HRU and costs (2017 U.S. dollars) were compared between cohorts during the 1-year study period following CRPC treatment initiation using the no corticosteroid cohort as reference. Multivariable regression models were used to adjust for baseline covariates, including age, region, index year, Charlson Comorbidity Index score, presence of bone metastases, baseline all-cause HRU, and corticosteroid-related clinical events during baseline.

RESULTS

9,425 patients were included (no corticosteroid = 6,765, low corticosteroid = 1,660, medium corticosteroid = 655, and high corticosteroid = 345). On average, patients in the no corticosteroid cohort were older and had a lower baseline HRU and comorbidity burden than patients in the other 3 cohorts. During the study period, patients with corticosteroid exposure (across all corticosteroid cohorts) had significantly more inpatient admissions (high corticosteroid vs. no corticosteroid adjusted incidence rate ratio [IRR] = 1.56; P < 0.001), emergency department visits (high corticosteroid vs. no corticosteroid adjusted IRR = 1.30; P = 0.001), and outpatient visits (high corticosteroid vs. no corticosteroid adjusted IRR = 1.11; P < 0.001). In addition, compared with the no corticosteroid cohort, patients with corticosteroid exposure had significantly higher monthly total costs (high corticosteroid vs. no corticosteroid adjusted difference = $2,600; P < 0.001), including medical service costs (high corticosteroid vs. no corticosteroid adjusted difference = $1,564; P < 0.001) and pharmacy costs (high corticosteroid vs. no corticosteroid adjusted difference = $825; P < 0.001).

CONCLUSIONS

Cumulative corticosteroid exposure before CRPC treatment initiation was associated with significantly higher HRU and costs. This increase in economic burden was more prominent among patients with annual cumulative corticosteroid doses of more than 2.0 gm. These results suggest that previous corticosteroid use may result in a higher economic burden among patients with CRPC.

DISCLOSURES

This study was funded by Astellas Pharma (Northbrook, IL) and Medivation, a Pfizer Company (San Francisco, CA), the codevelopers of enzalutamide. The study sponsor was involved in the study design, data interpretation, and review. All authors contributed to the development of the manuscript and maintained control over the final content. Schultz and Wilson are employed by Astellas Pharma. Schultz owns stock in Gilead Sciences and Shire. Song and Yang are employed by Analysis Group, which received consultancy fees from Astellas Pharma. Ramaswamy is employed by Pfizer, and Lowentritt is employed by Chesapeake Urology and has served as a speaker and consultant for Astellas Pharma, Pfizer, Bayer, Dendreon, and Janssen. A synopsis of the current research was presented in poster format at the AMCP Managed Care & Specialty Pharmacy Annual Meeting 2019, which took place in San Diego, CA, on March 25-28, 2019.

Effects of prednisone on docetaxel pharmacokinetics in men with metastatic prostate cancer: A randomized drug-drug interaction study

AIMS

Docetaxel has been approved for the treatment of metastatic prostate cancer in combination with prednisone. Since prednisone is known to induce the cytochrome P450 iso-enzyme CYP3A4, which is the main metabolizing enzyme of docetaxel in the liver, a potential drug-drug interaction may occur. In this prospective randomized pharmacokinetic cross-over study we investigated docetaxel exposure with concomitant prednisone, compared to docetaxel monotherapy in men with metastatic prostate cancer.

METHODS

Patients scheduled to receive at least 6 cycles of docetaxel (75 mg/m² ) and who gave written informed consent were randomized to receive either the 1^st 3 cycles, or the last 3 consecutive cycles with prednisone (twice daily 5 mg). Pharmacokinetic blood sampling was performed during cycle 3 and cycle 6. Primary endpoint was difference in docetaxel exposure, calculated as area under the curve (AUC_0-inf ) and analysed by means of a linear mixed model. Given the cross-over design the study was powered on 18 patients to answer the primary, pharmacokinetic, endpoint.

RESULTS

Eighteen evaluable patients were included in the trial. Docetaxel concentration with concomitant prednisone (AUC_0-inf 2784 ng*h/mL, 95% confidence interval 2436-3183 ng*h/mL) was similar to the concentration of docetaxel monotherapy (AUC_0-inf 2647 ng*h/mL, 95% confidence interval 2377-2949 ng*h/mL). Exploratory analysis showed no toxicity differences between docetaxel monotherapy and docetaxel cycles with prednisone.

CONCLUSION

No significant difference in docetaxel concentrations was observed. In addition, we found similar toxicity profiles in absence and presence of prednisone. Therefore, from a pharmacokinetic point of view, docetaxel may be administrated with or without prednisone.

Lipopolysaccharide (LPS) enhances prostate cancer metastasis potentially through NF-κB activation and recurrent dexamethasone administration fails to suppress it in vivo

BACKGROUND

Previous studies have shown the effect of bacterial lipopolysaccharide (LPS) on enhanced cancer cells' growth and metastasis. However, the effect of LPS on prostate cancer (PCa) cells metastasis has not been investigated in details. This study aimed to investigate the functional role of LPS on PCa cells metastasis and determine the effect of dexamethasone (DEX) on this event.

METHODS

Two different PCa reporter cells lines (DU145-NF-κB-Luc and MAT-LyLu- NF-κB-Luc) were used to assess the direct effect of LPS on NF-κB activation in PCa cells. Plasma collected from LPS-stimulated human and rodent blood were used to check the indirect effect of LPS on NF-κB activation in PCa cells. Trans-well migration assay and two different orthotopic PCa animal models were used to investigate the effect of LPS on DU145 and MAT-LyLu cells migration or metastasis in vitro and in vivo, respectively. In all the studies DEX was used with or without LPS stimulation.

RESULTS

LPS and secretory factors present in plasma collected from LPS-stimulated blood, significantly activated NF-κB in DU145, and MAT-LyLu cells and enhanced their migration in vitro. DEX significantly suppressed LPS-mediated activation of cancer and blood cells and abrogated the direct and indirect pro-migratory effect of LPS on PCa cells. Systemic administration of LPS activated NF-κB in DU145 cells in vivo; however, failed to alter the metastatic properties of these cells. On the other hand, systemic administration of LPS to MAT-LyLu tumor bearing animals significantly enhanced the incidence of metastasis without altering the overall growth of primary tumors. Unexpectedly, though DEX significantly suppressed MAT-LyLu primary tumor weights, it aggravated metastasis of cancer cells in presence and absence of LPS. Moreover, consecutive DEX pre-treatment enhanced experimental peritoneal metastasis of MAT-LyLu cells. At the molecular level, LPS, and/or DEX induced overexpression of immunosuppressive molecules in MAT-LyLu tumors.

CONCLUSIONS

Overall, our study has shown that LPS and/or LPS induced inflammation can increase PCa metastasis and immunosuppressive dose of DEX might further enhance cancer metastasis.

Parameter identification of a model for prostate cancer treated by intermittent therapy

Adenocarcinoma is the most frequent cancer affecting the prostate walnut-size gland in the male reproductive system. Such cancer may have a very slow progression or may be associated with a "dark prognosis" when tumor cells are spreading very quickly. Prostate cancers have the particular properties to be marked by the level of prostate specific antigen (PSA) in blood which allows to follow its evolution. At least in its first phase, prostate adenocarcinoma is most often hormone-dependent and, consequently, hormone therapy is a possible treatment. Since few years, hormone therapy started to be provided intermittently for improving patient's quality of life. Today, durations of on- and off-treatment periods are still chosen empirically, most likely explaining why there is no clear benefit from the survival point of view. We therefore developed a model for describing the interaction between the tumor environment, the PSA produced by hormone-dependent and hormone-independent tumor cells, respectively, and the level of androgens. Model parameters were identified using a genetic algorithm applied to the PSA time series measured in a few patients who initially received prostatectomy and were then treated by intermittent hormone therapy (LHRH analogs and anti-androgen). The measured PSA time series is quite correctly reproduced by free runs over the whole follow-up. Model parameter values allow for distinguishing different types of patient (age and Gleason score) meaning that the model can be individualized. We thus showed that the long-term evolution of the cancer can be affected by durations of on- and off-treatment periods.

PSA response following the 'steroid switch' in patients with castration-resistant prostate cancer treated with abiraterone: A case report

A 69-year-old man presented initially with back pain and incomplete bilateral lower limb paralysis. The level of prostate-specific antigen (PSA) in the patient was elevated to 167.0 ng/ml, and multiple bone metastases were detected. Thoracic laminectomy was performed in an emergency due to spinal decompression. Subsequently, the patient was diagnosed with prostate cancer from an examination of resected bone specimens. Combined androgen blockade with degarelix and bicalutamide was initiated in October 2013. Consequently, the serum PSA level decreased to <1.0 ng/ml, but thereafter gradually increased. Subsequent bicalutamide withdrawal response was not observed, and switch of anti-androgen therapy to flutamide also resulted in a poor response. Then, abiraterone (1,000 mg daily) in combination with prednisolone (10 mg daily) was initiated when the level of PSA increased to 35.9 ng/ml in June 2015. The level of PSA decreased to the lowest point of 4 ng/ml; however, PSA level increased again to 21.7 ng/ml in April 2016. Consequently, a 'steroid switch' was attempted. Abiraterone therapy was continued, but concomitant corticosteroid was switched from prednisone to dexamethasone (1.0 mg per day). Fortunately, serum PSA level decreased promptly to the lowest point of 0.6 ng/ml. In the present case report, a review of recent literature was presented and potential explanations of the mechanism underlying the 'steroid switch' were described. Pharmacokinetic differences between dexamethasone and prednisolone may partially explain why the 'steroid switch' occurs. Other mechanisms may include the activation of the glucocorticoid receptor, mineralocorticoid receptor and/or mutant androgen receptor. Corticosteroids accelerate a number of transcription factors, cellular growth factors and cytokines, which may also be potential mechanisms. The 'steroid switch' at PSA progression might be a feasible option for therapy, which may delay the development of the disease. Although the underlying mechanisms require further study, clinicians should pay attention to this phenomenon.

The evolving landscape of metastatic hormone-sensitive prostate cancer: a critical review of the evidence for adding docetaxel or abiraterone to androgen deprivation

BACKGROUND

Until 2015, androgen deprivation therapy (ADT) alone was the standard-of-care for metastatic hormone-sensitive prostate cancer (mHSPC). In 2015, the CHAARTED and STAMPEDE-Docetaxel studies demonstrated marked survival benefit with the addition of docetaxel to ADT in the mHSPC setting, leading to a change in the standard-of-care for mHSPC. The recent LATITUDE and STAMPEDE-Abiraterone trials showed similar substantial improvement in survival with the addition of abiraterone plus prednisone to ADT in this space.

METHODS

We conducted a review of the randomized phase III studies that have investigated either the addition of docetaxel or abiraterone to ADT in patients with mHSPC.

RESULTS

We describe the study designs, key eligibility criteria, and key results for the CHAARTED, STAMPEDE-Docetaxel, GETUG-AFU 15, LATITUDE, and STAMPEDE-Abiraterone clinical trials. We compare the data for abiraterone/prednisone plus ADT in mHSPC with the evidence for docetaxel plus ADT in these patients. Finally, we discuss several factors that should be considered when choosing between docetaxel/ADT or abiraterone/prednisone/ADT in mHSPC.

CONCLUSIONS

The management of mHSPC is evolving. Abiraterone plus prednisone in addition to ADT has emerged as an alternative standard-of-care to docetaxel plus ADT, and ongoing trials should clarify whether combination vs. sequential approaches with AR-targeting agents and taxane chemotherapy are preferred for initial management in the hormone-sensitive setting.

The role of glucocorticoid receptor in prostate cancer progression: from bench to bedside

Glucocorticoids are a common class of adjuvant drugs for the treatment of castration-resistant prostate cancer (CRPC) combined with antitumour or antiandrogen agents. Glucocorticoids are administered clinically because they ameliorate toxic side effects and have inhibitory effects on adrenal androgen production, acting as a pituitary suppressant. However, their effects on prostate cancer cells especially the castration resistance prostate cancer cells are poorly defined. Glucocorticoids exert effects depend to a great extent on glucocorticoid receptor. In addition to a number of glucocorticoid receptor isoforms determined, it is found that the actions of glucocorticoids through GRα are influenced by other isoforms, such as GRβ and GRγ. Recently, studies found GR confers resistance to androgen deprivation therapy, and various glucocorticoids exert distinct efficacy in CRPC. In this review, we summarized the mechanisms of glucocorticoids and its clinical appliances on the basis of present evidence.

Treatment of metastatic castration-resistant prostate cancer (mCRPC) with enzalutamide

Prostate cancer is initially responsive to androgen deprivation therapy, but most patients eventually develop castration-resistant disease. Enzalutamide is an androgen receptor (AR) inhibitor that targets several steps in the AR signaling pathway and has shown significant efficacy in the treatment of metastatic castration-resistant prostate cancer in patients with or without prior chemotherapy. To provide optimal treatment, it is important to understand the implications of enzalutamide use in the context of other therapies, as recent findings have suggested cross-resistance occurs between and within drug classes. Mutations and splice variants of AR also impact the course of prostate cancer. Future strategies involving enzalutamide should account for previous exposure to taxanes or antiandrogen therapies and the presence of AR variants that could affect efficacy.