Enzalutamide in Japanese patients with chemotherapy-naïve, metastatic castration-resistant prostate cancer: A post-hoc analysis of the placebo-controlled PREVAIL trial

Determination of enzalutamide long-term safety and efficacy for castration-resistant prostate cancer patients after combined anti-androgen blockade followed by alternative anti-androgen therapy: a multicenter prospective DELC study

BACKGROUND

Alternative anti-androgen therapy has been widely used as a first-line treatment for castration-resistant prostate cancer, and it may affect treatment outcome of subsequent agents targeting the androgen receptor axis. We conducted the prospective observational DELC (Determination of Enzalutamide Long-term safety and efficacy for Castration-resistant prostate cancer patients after combined anti-androgen blockade followed by alternative anti-androgen therapy) study to evaluate the efficacy of enzalutamide in patients with castration-resistant prostate cancer who underwent prior combined androgen blockade with bicalutamide and then alternative anti-androgen therapy with flutamide.

METHODS

The DELC study enrolled 163 Japanese patients with castration-resistant prostate cancer who underwent alternative anti-androgen therapy with flutamide following failure of initial combined androgen blockade with bicalutamide in multiple institutions between January 2016 and March 2019. Primary endpoint was overall survival. Administration of enzalutamide was started at 160 mg orally once daily in all patients.

RESULTS

The rate of decline of prostate-specific antigen by 50% or more was 72.2%, and median overall survival was 42.05 months. Multivariate analysis revealed that higher pretreatment serum levels of prostate-specific antigen (≥11.3 ng/mL; P = 0.004), neuron-specific enolase (P = 0.014) and interleukin-6 (≥2.15 pg/mL; P = 0.004) were independent risk factors for overall survival. Fatigue (30.0%), constipation (19.6%) and appetite loss (17.8%) were the most common clinically relevant adverse events. The enzalutamide dose was not reduced in any patient under the age of 70, but adherence was decreased in those over 70.

CONCLUSIONS

In the DELC study, the safety of enzalutamide was comparable to that in previous reports. Serum levels of neuron-specific enolase and interleukin-6 were suggested as prognostic factors for castration-resistant prostate cancer with potential clinical utility.

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.

Initial dose reduction of enzalutamide does not decrease the incidence of adverse events in castration-resistant prostate cancer

Background

There was no clear evidence whether the initial dose of enzalutamide affects the incidence of adverse events (AEs), and oncological outcome in patients with castration-resistant prostate cancer (CRPC).

Methods

The clinical charts of 233 patients with CRPC treated with enzalutamide were reviewed retrospectively. After 1:3 propensity score matching (PSM), 124 patients were divided into a reduced dose group and a standard dose group, and the prostate specific antigen (PSA) response and the incidence of AEs were compared.

Results

190 patients with CRPC initiated with standard dose enzalutamide were younger and better performance status compared with 43 patients beginning with reduced dose. After PSM, the baseline characteristics were not different between the standard and the reduced dose group. In the PSM cohort, the PSA response rate was significantly lower in the reduced dose group than in the standard dose group (-66.3% and -87.4%, p = 0.02). The incidence rates of AEs were not statistically different between the groups (22.6% and 34.4%, respectively, p = 0.24).

Conclusion

Initiating treatment with a reduced dose of enzalutamide did not significantly decrease the incidence rate of AEs, and it showed poorer PSA response rate. There is no clear rationale for treating with a reduced initial dose of enzalutamide to reduce the incidence of AEs.

High Tumor Burden Predicts Poor Response to Enzalutamide in Metastatic Castration-Resistant Prostate Cancer Patients

Simple Summary

Several available medications are involved in the treatment of metastatic castration-resistant prostate cancer (mCRPC). In this Taiwanese mCRPC cohort receiving enzalutamide patients with high tumor burden (HTB) were defined as those with either appendicular bony metastasis or visceral metastasis. A high tumor burden reduced the PSA response rate, radiological response rate, and progression-free survival duration. In addition, patients’ comorbidities and laboratory data—such as ALP, LDH, ALT, and hemoglobin—were correlated with the treatment efficacy of enzalutamide. Our study revealed a tumor burden before the use of enzalutamide was associated with treatment outcomes. The physician can use this information to estimate the response rate of enzalutamide and help formulate a personalized treatment plan for mCRPC patients.

Abstract

To assess the predictive value of tumor burden on the biochemical response, and radiological response in Taiwanese metastatic castration-resistant prostate cancer (mCRPC) patients receiving enzalutamide. The mCRPC patients treated with enzalutamide were recruited from three hospitals. High tumor burden (HTB) was classified as metastases at either appendicular bone or visceral organ. Good prostate-specific antigen (PSA) response was defined as PSA reduction of 80%. In this cohort, there were 104 (54.2%) HTB patients and 88 (45.8%) with low tumor burden (LTB). Compared to LTB patients, fewer HTB patients had good PSA response (odds ratio: 0.43, range: 0.22–0.87, p = 0.019) and fewer radiological response (complete and partial remission) (odds ratio: 0.78, range: 0.36–1.68, p = 0.52) to enzalutamide. The disease control rate which also contained stable disease, was still lower in HTB (76.0%) than LTB group (92.9%, OR: 0.24, range: 0.07–0.77, p = 0.016) in the multivariable model. In addition, HTB patients had significantly shorter progression–free survival duration than did LTB patients (median: 8.3 vs. 21.6 months, log-rank test p = 0.003) in the univariable analysis. The tumor burden before the use of enzalutamide was associated with treatment outcomes. HTB reduced PSA response rate, radiological response rate and progression-free survival duration.

Enzalutamide with androgen deprivation therapy in Japanese men with metastatic hormone-sensitive prostate cancer: A subgroup analysis of the phase III ARCHES study

Objective

To evaluate the efficacy and safety of enzalutamide plus androgen deprivation therapy in Japanese men with metastatic hormone‐sensitive prostate cancer.

Methods

A post‐hoc analysis of the Japanese subgroup in the phase III, randomized, multinational ARCHES study (NCT02677896) was carried out. Patients with metastatic hormone‐sensitive prostate cancer were randomized to receive enzalutamide or a placebo, plus androgen deprivation therapy, stratified by disease volume and prior docetaxel therapy. The primary end‐point was radiographic progression‐free survival. Secondary end‐points included time to prostate‐specific antigen progression and overall survival.

Results

Of 1150 patients, 92 Japanese patients were randomized to enzalutamide (n = 36) or a placebo (n = 56), plus androgen deprivation therapy; none received prior docetaxel. Enzalutamide plus androgen deprivation therapy reduced the risk of radiographic progression or death in Japanese patients by 61% versus the placebo, similar to the overall population. Similar results were observed with secondary end‐points, showing clinical benefit of enzalutamide plus androgen deprivation therapy in Japanese patients. Overall survival data were immature. Grade 3–4 adverse events were reported in 47% and 25% of the enzalutamide and placebo groups, respectively. Nasopharyngitis, hypertension and abnormal hepatic function were reported more frequently in Japanese patients versus the overall population.

Conclusions

Enzalutamide plus androgen deprivation therapy has clinical benefit with a tolerable safety profile in Japanese men with metastatic hormone‐sensitive prostate cancer, consistent with the overall population.

Comparison of efficacy outcomes of anticancer drugs between Japanese patients and the overall population

BACKGROUND

It is important to recognize regional and racial differences in drug efficacy and safety when performing multi-regional clinical trials (MRCTs). To understand regional differences, we compared the efficacy results in Japanese patients and the overall population in the MRCTs of anticancer drugs.

METHODS

All new approvals of oncology drugs in Japan from January 2009 to December 2018 were searched using the Pharmaceuticals and Medical Devices Agency web site to find phase 3 MRCTs for the analysis. As the supporting data source, a literature search was performed in PubMed and Google Scholar. Linear regression analysis was performed and Pearson correlation coefficients (r) were calculated to compare the overall survival (OS), progression-free survival (PFS), and objective response rate (ORR) between Japanese patients and the overall population.

RESULTS

Seventy MRCTs were identified. The correlation of hazard ratios (HRs) for OS between Japanese patients and the overall population was moderate (r = 0.45), and OS was 1.31 times longer in Japanese patients than in the overall population, although the correlation of median OS was strong (r = 0.91). The HRs for PFS were moderately correlated (r = 0.70) and the correlation of median PFS was strong (r = 0.90). The correlation of ORR was very strong (r = 0.96).

CONCLUSION

The PFS and ORR were consistent between Japanese patients and the overall population. A longer median OS was observed in Japanese patients. Our results would be a useful reference when planning and conducting MRCTs that include Japan for global simultaneous drug development.

Efficacy, Prognostic Factors, and Safety Profile of Enzalutamide for Non-metastatic and Metastatic Castration-Resistant Prostate Cancer: A Retrospective Single-Center Analysis in Japan

BACKGROUND

Enzalutamide is a novel, non-steroidal anti-androgen that has demonstrated excellent anti-tumor activity for both non-metastatic and metastatic castration-resistant prostate cancer (nmCRPC and mCRPC) patients, and that is being rapidly introduced into clinical practice in Japan.

OBJECTIVE

We retrospectively investigated the treatment efficacy, safety profile, and prognostic factors of enzalutamide over a relatively long observation period in Japanese patients with nmCRPC and mCRPC.

PATIENTS AND METHODS

The medical records of 184 consecutive Japanese patients with nmCRPC and mCRPC who started enzalutamide treatment in our institution between January 2012 and April 2018 were reviewed. Efficacy and safety profiles were assessed and statistically analyzed.

RESULTS

Among these 184 patients, 44 (23.9%) nmCRPC patients, 89 (48.4%) docetaxel-naïve mCRPC patients, and 51 docetaxel-pretreated (27.7%) mCRPC patients underwent enzalutamide therapy. The median prostate-specific antigen progression-free survival (PSA-PFS) and overall survival (OS) periods for nmCRPC patients were 39.2 months and not reached; those for docetaxel-naïve mCRPC patients were 16.5 months and 59.8 months; and those for docetaxel-pretreated mCRPC patients were 7.0 months and 30.4 months, respectively. Multivariate analysis identified performance status ≥ 2, PSA > 8.89 ng/mL (median value), hemoglobin < lower limit of normal range, neutrophil to lymphocyte ratio > 3.0, and 4-week PSA decline < 50% as the predictive factors for shorter OS. Our respective prognostic models using these factors successfully demonstrated distinctly separated survival curves (p < 0.001). In addition, among these patients, 30 (16.3%) experienced adverse events and 16 (8.7%) experienced adverse events resulting in the discontinuation of therapy. Fatigue (14%) and appetite loss (7%) were the most common such events.

CONCLUSIONS

Both the survival period and risk factors were extracted from a relatively long-term observation period. Since enzalutamide was approved for administration to patients with castration-sensitive prostate cancer earlier this year (2020), we believe that the data presented here will be useful for both physicians and patients in clinical practice.

Efficacy and Safety of Non-Steroidal Anti-Androgens in Patients with Metastatic Prostate Cancer: Meta-Analysis of Randomized Controlled Trials

BACKGROUND

Prostate cancer (PCa) is the sixth primary cause of cancer death. However, conflicts are present about the efficacy and safety of Non-steroidal anti-androgens (NSAA) for its treatment. The aim of this study was to assess the efficacy and safety of NSAAs versus any comparator for the treatment of advanced or metastatic PCa (mPCa).

METHODS

MEDLINE and the Cochrane Library were searched. References of included studies and clinicaltrials.gov were also searched for relevant studies. Only English language studies after 1990 were considered for review. Randomized controlled trials (RCTs) examining the efficacy and safety of NSAAs as compared with any other comparator including surgery or chemotherapy in mPCa patients were included. The outcomes include efficacy, safety and the tolerability of the treatment. The Cochrane Risk of Bias Assessment Tool was used for quality assessment. Two authors were independently involved in the selection, extraction and quality assessment of included studies and disagreements were resolved by discussion or by consulting a third reviewer.

RESULTS

Fifty-eight out of 1307 non-duplicate RCTs with 29154 patients were considered for the review. NSAA showed significantly better progression-free survival [PFS] (Hazard ratio [HR], 0.60; 95% confidence interval [CI], 0.46-0.78; P=0.0001), time to distant metastasis or death [TTD] (HR, 0.80; 95% CI 0.73-0.91; P<0.0001), objective response (Odds ratio [OR], 1.64; 95% CI 1.06-2.54; P=0.03) and clinical benefits (OR, 1.33; 95% CI 1.08-1.63; P=0.006) as compared to the control group. There was no significant difference observed between the groups in terms of overall survival (HR, 0.95; 95%CI, 0.87-1.03; P=0.18) and time to progression (HR, 0.93; 95% CI 0.77-1.11; P=0.43). Treatment-related adverse events were more with the NSAA group, but the discontinuation due to lack of efficacy reason was 43% significantly lesser than the control group in patients with mPCa. Rest of the outcomes were appeared to be non-significant.

CONCLUSION

Treatment with NSAA was appeared to be better efficacious with respect to PFS, TTD, and response rate with considerable adverse events when compared to the control group in patients with metastatic PCa.

Enzalutamide: A Review in Castration-Resistant Prostate Cancer

Oral enzalutamide (Xtandi^®), a second generation androgen receptor inhibitor, is indicated for the treatment of castration-resistant prostate cancer (CRPC) in numerous countries worldwide, with specific indications in this patient population varying between individual countries. Based on extensive experience in the clinical trial and/or real-world settings, oral enzalutamide 160 mg once daily is an effective and generally well tolerated treatment in a broad spectrum of patients with CRPC, including in nonmetastatic and metastatic disease and in chemotherapy-naive and -experienced metastatic CRPC. Enzalutamide is an emerging option for the treatment of men with nonmetastatic CRPC who are at high-risk for developing metastatic disease, and remains an important first-line option in chemotherapy-naive or -experienced patients with metastatic CRPC.

Enzalutamide versus flutamide for castration-resistant prostate cancer after combined androgen blockade therapy with bicalutamide: study protocol for a multicenter randomized phase II trial (the OCUU-CRPC study)

Background

Enzalutamide is an oral androgen receptor targeted agent that has been shown to improve survival in PREVAIL trials and has been approved for patients with chemo-naïve metastatic castration-resistant prostate cancer (CRPC). Meanwhile, flutamide is a non-steroidal oral anti-androgen that was commonly used before the approval of bicalutamide. The objective of the OCUU-CRPC study is to compare the efficacy and safety between second-line hormonal therapy of enzalutamide and flutamide as alternative anti-androgen therapy (AAT) after combined androgen blockade (CAB) therapy that included bicalutamide in patients with CRPC.

Methods

A total of 100 patients with CRPC with or without distant metastases after disease progression who received CAB therapy with bicalutamide were randomly assigned at a 1:1 ratio according to distant metastases to the enzalutamide (160 mg/day, 4 × 40 mg capsules once daily) and flutamide (375 mg/day; 3 × 125 mg tablets thrice daily) groups. The primary endpoint for the drug efficacy is the response rate of prostate-specific antigen (PSA) (i.e., the ratio of patients whose PSA declined by ≥50% from baseline) at 3 months. Meanwhile, the secondary endpoints are PSA progression rate at 3 and 6 months, PSA response rate at 6 months, change in quality of life, PSA progression-free survival, and safety. The patient registration started in January 2015 and will end in March 2018, and the follow-up period is 6 months after the last patient registration. The main result will be reported in March 2019.

Discussion

In the OCUU-CRPC study, we compare the efficacy and safety of enzalutamide or alternative AAT with flutamide in participants with CRPC who were previously treated with a CAB therapy with bicalutamide. The expected results of this study will be that enzalutamide is superior to flutamide in terms of PSA response. A longer time to disease progression with enzalutamide over flutamide may translate to better overall survival. However, flutamide may be more accessible for patients owing to its lower cost than enzalutamide.

Trial registration

The OCUU-CRPC study was prospectively registered at clinicaltrials.gov (NCT02346578, January 2015) and University Hospital Medical Information Network (UMIN000016301, January 2015).

Survival Outcomes, Prostate-specific Antigen Response, and Tolerance in First and Later Lines of Enzalutamide Treatment for Metastatic Castration-resistant Prostate Cancer: A Real-World Experience in Hong Kong

BACKGROUND

The present study retrospectively evaluated the efficacy and safety of enzalutamide in different lines of metastatic castration-resistant prostate cancer (mCRPC) treatment in a real-world setting.

PATIENTS AND METHODS

The clinical records of patients with mCRPC treated with enzalutamide between August 2015 and October 2017 were retrieved from all 7 public oncology centers in Hong Kong and reviewed. The primary endpoint was progression-free survival (PFS) in first (1L), second (2L), and third or fourth lines (3L or 4L) of CRPC treatment. Secondary endpoints included overall survival (OS), prostate-specific antigen (PSA) response, and tolerance.

RESULTS

Among a total of 117 patients (median age of 73 years [range, 52-90 years]), 34 (29.1%), 57 (48.7%), and 26 (19.3%) patients had enzalutamide as their 1L (chemo-naive), 2L (post-docetaxel or -abiraterone), and 3L or above treatment options. The overall PSA response rates were 43.6%, and were 73.5%, 35.1%, and 19.2% for 1L, 2L, and 3L or 4L treatment, respectively. PFS and OS were significantly associated with the line of treatment in the univariate survival analysis (1L/2L/3L and 4L; PFS, 7.1/3.9/2.2 months; OS, not reached/15.8/7.4 months; both P = .0002) but not in the multivariate analysis. The observed incidence of any fatigue (grade 1 or 2, 54.7%; grade 3 or 4, 9.4%) was much higher than reported in the AFFIRM (A Study Evaluating the Efficacy and Safety of the Investigational Drug MDV3100 [ClinicalTrials.gov Identifier: NCT00974311]) (any grade, 34%) and PREVAIL (A Multinational Phase 3, Randomized, Double-blind, Placebo-controlled Efficacy And Safety Study Of Oral Mdv3100 In Chemotherapy-naïve Patients With Progressive Metastatic Prostate Cancer Who Have Failed Androgen Deprivation Therapy [ClinicalTrials.gov Identifier: NCT00974311]) (any grade, 36%) trials; as well, grade ≥ 2 fatigue was significantly associated with 3L or 4L treatment (P = .01 in both univariate and multivariate analyses).

CONCLUSION

In the real-life setting, there was a higher incidence of enzalutamide-related fatigue than reported in the trials. Earlier lines of enzalutamide treatment were associated with longer PFS and OS, more frequent PSA response, and less fatigue.

Cabazitaxel-conjugated nanoparticles for docetaxel-resistant and bone metastatic prostate cancer

Effective treatment of metastatic castration resistant prostate cancer (mCRPC) remains an unmet challenge. Cabazitaxel (CBZ) is approved for mCRPC after docetaxel (DTX) failure, but the improvement in survival is only moderate (∼2 months) and patients suffer from significant side effects. Here, we report the development of a polymer based delivery system for CBZ to improve its safety and efficacy against DTX-resistant mCRPC. CBZ was conjugated to a carboxymethylcellulose-based polymer (Cellax-CBZ), which self-assembled into ∼100 nm particles in saline and exhibited sustained drug release in serum at 10%/day. Cellax-CBZ delivered 157-fold higher CBZ to PC3-RES prostate tumor in mice and could be safely administered at a 25-fold higher dose compared to free CBZ, resulting in superior tumor inhibition in multiple mice models of DTX-resistant CRPC. In a metastatic bone model of CRPC, Cellax-CBZ significantly improves overall survival with a 70% long-term survival rate to day 120, while mice treated with free CBZ had a median survival of 40 days. Cellax-CBZ induced mild and reversible neutropenia in mice but no other tissue damage. Cellax-CBZ showed significant potential for improving therapy of mCRPC over clinically approved CBZ.

Therapies for castration-resistant prostate cancer in a new era: The indication of vintage hormonal therapy, chemotherapy and the new medicines

When advanced prostate cancer recurred during hormonal therapy and became the castration-resistant prostate cancer, "vintage hormonal therapy," such as antiandrogen alternating therapy or estrogen-related hormonal therapy, was widely carried out in Japan until 2013. This vintage hormonal therapy controlled the progression of castration-resistant prostate cancer. When castration-resistant prostate cancer relapses during these therapies, chemotherapy using docetaxel has been carried out subsequently. Since new hormonal therapies using abiraterone acetate and enzalutamide, which improve the prognosis of castration-resistant prostate cancer, became available in Japan from 2014, therapeutic options for castration-resistant prostate cancer have increased. Furthermore, the improvement of the further prognosis is promising by using cabazitaxel for docetaxel-resistant castration-resistant prostate cancer and radium-223 for castration-resistant prostate cancer with bone metastasis. An increase in therapeutic options gives rise to many questions, including best timing to use them and the indication. Furthermore, physicians have to consider the treatment for the recurrence after having carried out chemotherapy. We want to argue the difference in hormonal therapy between Japan and Western countries, and problems when carrying out new treatments, and the importance of imaging in the present review article.

Post hoc analysis of Japanese patients from the placebo-controlled PREVAIL trial of enzalutamide in patients with chemotherapy-naive, metastatic castration-resistant prostate cancer-updated results

A post hoc analysis of interim results from PREVAIL, a Phase III, double-blind, placebo-controlled trial of men with metastatic castration-resistant prostate cancer, demonstrated that the treatment effects, safety and pharmacokinetics of enzalutamide in Japanese patients were generally consistent with those of the overall population. A recent longer term analysis of PREVAIL demonstrated continued benefit of enzalutamide treatment over placebo. Here, we report results from a post hoc analysis of Japanese patients enrolled in PREVAIL at the prespecified number of deaths for the final analysis. In Japanese patients, enzalutamide reduced the risk of death by 35% (hazard ratio, 0.65; 95% confidence interval, 0.28–1.51) and the risk of investigator-assessed radiographic progression or death by 60% (hazard ratio, 0.40; 95% confidence interval, 0.18–0.90). These results show that treatment effects and safety in Japanese patients in the final analysis of PREVAIL continued to be generally consistent with those of the overall population.

Patient preferences for treatment of castration-resistant prostate cancer in Japan: a discrete-choice experiment

Background

Up to a fifth of patients diagnosed with prostate cancer (PC) will develop castration-resistant prostate cancer (CRPC), which has been associated with a poor prognosis. The aim of this study was to consider the patient perspective as part of the overall treatment decision-making process for CRPC, given that an alignment between patient preference and prescribing has been shown to benefit patient outcomes. This study examines preferences of patients with CRPC in Japan for treatment features associated with treatments like RA-223, abiraterone, and docetaxel and to examine the extent to which treatment preferences may vary between symptomatic and asymptomatic patients.

Methods

A two-phase research approach was implemented. In Phase 1, N = 8 patients with CRPC were recruited from a single hospital to complete a qualitative interview to provide feedback on the draft survey. In Phase 2, N = 134 patients with CRPC were recruited from five hospitals to complete a paper survey. The survey included 6 treatment choice questions, each asking patients to choose between two hypothetical treatments for their CRPC. Each treatment alternative was defined by the following attributes: length of overall survival (OS), time to a symptomatic skeletal event (SSE), method of administration, reduction in the risk of bone pain, treatment-associated risk of fatigue and lost work days. A hierarchical Bayesian logistic regression was used to estimate relative preference weights for each attribute level and mean relative importance.

Results

A total of N = 133 patients with CRPC completed the survey and were included in the final analysis. Patients had a mean age of 75.4 years (SD = 7.4) and had been diagnosed with PC a mean of 6.5 years prior (SD = 4.4). Over the attribute levels shown, fatigue (relative importance [RI] = 24.9 %, 95 % CI: 24.7 %, 25.1 %) was the most important attribute, followed by reduction in the risk of bone pain (RI = 23.2 %, 95 % CI: 23.0 %, 23.5 %), and OS (RI = 19.2 %, 95 % CI: 19.0 %, 19.4 %). Although symptomatic patients placed significantly more importance on delaying an SSE (p < .05), no other preference differences were observed.

Conclusions

CRPC patients were more concerned about reduced quality of life from side effects of treatment rather than extension of survival, which may have implications for shared decision-making between patients and physicians.

Influences of the Results from STRIVE Trial on the Combination Androgen Depletion Therapy for Advanced Prostate Cancer

The clinical efficacy of combined therapy (CAB) has been clearly recognized by the results of the STRIVE trial. Although enzalutamide has shown a stronger effect on CRPC, bicultamide, a classical anti-androgen, has shown a significant effect. In addition, it can be deduced that CAB is a strong tool for hormone naïve advanced prostate cancer. Cost-effective evaluation for CAB with bicultamide or enzalutamide is warranted, especially for the resource-limited cohort.