Prior long response to androgen deprivation predicts response to next-generation androgen receptor axis targeted drugs in castration resistant prostate cancer

Outcomes and patterns of use of Radium-223 in metastatic castration-resistant prostate cancer

Introduction

Radium-223 dichloride (Ra-223) is recommended as a treatment option for metastatic castration-resistant prostate cancer (mCRPC) patients with symptomatic bone metastases and no visceral disease, after docetaxel failure, or in patients who are not candidates to receive it. In this study, we aimed to ambispectively analyze overall survival (OS) and prognostic features in mCRPC in patients receiving Ra-223 as per clinical routine practice and identify the most suitable treatment sequence.

Patients and methods

This study is observational, multicentric, and ambispective. Eligibility criteria included mCRPC patients treated with Ra-223, with an Eastern Cooperative Oncology Group (ECOG) performance status of 0-2, without visceral metastases, and no more than three cm involved lymph nodes.

Results

A total of 145 patients were included; the median age was 73.97 years, and a Gleason score of more than or equal to 7 in 61 (48%) patients; 73 (81%) had previously received docetaxel. The most important benefit was reached by those patients who received Ra-223 in the second-line setting, with a median OS of 17 months (95% CI, 12-21), and by patients who received six cycles of treatment, with a median OS of 19 months (95% CI, 14-21). An alkaline phosphatase (ALP) decrease was also identified as a prognosis marker. When performing the multivariate analysis, the time to develop castration-resistant disease longer than 24 months was the most important prognostic factor to predict the evolution of the patients receiving Ra-223. Ra-223 was well tolerated, with thrombocytopenia, anemia, and diarrhea being the main adverse events.

Conclusion

There is a benefit for those patients who received Ra-223 in the second-line setting, regardless of prior use of docetaxel. In addition, a survival benefit for patients presenting with a decline in ALP was observed.

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

BACKGROUND AND OBJECTIVE

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

METHODS

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

KEY FINDINGS AND LIMITATIONS

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

CONCLUSIONS AND CLINICAL IMPLICATIONS

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

PATIENT SUMMARY

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

Initial management approach for localized/locally advanced disease is critical to guide metastatic castration-resistant prostate cancer care

BACKGROUND

Currently, several therapies are available for metastatic castration-resistant prostate cancer (mCRPC) but no specific clinical factors to personalize treatment. We first sought the prognostic value of duration on androgen-deprivation therapy (ADT) for hormone-sensitive prostate cancer (HSPC) in patients receiving androgen-receptor-signaling inhibitors (ARSI) for mCRPC.

METHODS

A multicenter cohort of mCRPC patients who started ARSI between July 2011 and October 2021 was identified. Based on their initial disease burden and duration on ADT for HSPC, primary progressive (PP) men were classified into four groups: low/intermediate-risk localized disease (LOC) and high-risk localized/locally advanced disease (LAD) and short-term (ST) < 24 vs. long-term (LT) ADT ≥ 24 months, whereas de novo (DN) mHSPC were subdivided into short-time vs. long-time to CRPC.

RESULTS

We included 919 mCRPC patients with a median age of 77 years [interquartile range (IQR) = 71-82)]. Median ADT duration in HSPC was 24 months (IQR = 14-40). Median follow-up was 91 months (IQR = 62-138), median OS and PFS from ARSI start were 20 (IQR 10-32) and 10 months (IQR = 5-19), respectively. In PP developing metastatic disease (n = 655, 71.3%), LOC and LAD with ST ADT had a greater than almost double-risk of death compared to LT ADT (LOC/ST: hazard ratio [HR] = 2.01; 95% CI 1.54-2.64; LAD/ST: HR = 1.73; 95% CI 1.34-2.24; p < 0.001). In the multivariate analysis including age, prognostic cohort, Gleason, ECOG, radical radiotherapy and prostatectomy, groups with ST ADT were associated with worse OS compared to LT ADT (LOC/ST: HR = 1.84; 95% CI 1.38-2.45; p < 0.001; LAD/ST: HR = 1.59; 95% CI 1.21-2.10; p < 0.001), along with ECOG > 2 (HR = 1.55; 95% CI 1.06-2.26; p = 0.03). There were also similar results of PFS. Moreover, long-time to CRPC in patients with history of DN mHSPC (n = 264, 28.7%) resulted in a better OS/PFS (HR = 0.76, 95% CI 0.56-1.02, p = 0.064 and HR = 0.74, 95% CI 0.55-0.99, p = 0.042, respectively).

CONCLUSIONS

Our study showed that duration on ADT for mHSPC was significantly associated with survival in mCRPC undergoing ARSI. These findings suggest a possible connection between initial management of prostate tumour and a better prognostication in mCRPC. Prospective trials are warranted.

Real-World Treatment Patterns Among French Patients With Metastatic Castration-Resistant Prostate Cancer Under Abiraterone or Enzalutamide

PURPOSE

Using large French retrospective study cohort of chemotherapy-naïve metastatic castration-resistant prostate cancer patients (mCRPC; n = 10,308) comparing survival between patients who initiated abiraterone (ABI; 64%) and those initiating enzalutamide (ENZ; 36%), the present objective was to describe treatment patterns in the 2 years following initiation.

METHOD

Using the national health data system (SNDS) from 2014 to 2018, we first explored the number of treatment lines, and secondly, patterns of patient management using state sequence analysis; cluster analyses were performed on the 0 to 12 month and 13 to 24 month periods. Age, Charlson score, and duration of androgen deprivation therapy (ADT) were obtained for each cluster in the first year of follow-up.

RESULTS

Patients with only 1 treatment line accounted for 52%. In the 0 to 12 month sequence analysis, the main clusters among ABI/ENZ new users involved patients who continued the initial treatment (54% of 65% respectively) and discontinued active treatment (14.5% for both). Less than 2 years exposure to ADT prior to ABI/ENZ initiation was frequently observed for noncontrolled mCRPC, as shown in the death and switch from ABI/ENZ to docetaxel clusters. The clusters for a switch ABI/ENZ to ENZ/ABI involved 6% to 11% of the patients.

CONCLUSION

Our study suggested fairly similar patterns between ABI and ENZ initiation. The cluster of patients with active treatment discontinuation needs to be further investigated, as well as factors influencing therapeutic choice. Better understanding for the use of second-generation hormone therapy in mCRPC in real life, could improve its implementation by clinicians in the early stages of prostate cancer.

Clinical characteristics of patients with metastatic castration-resistant prostate cancer after treatment with combined androgen blockade

BACKGROUND

Although the second-generation androgen receptor inhibitors and taxanes have recently been recommended for the initial treatment of metastatic prostate cancer, bicalutamide and flutamide are still used in a large number of cases. Therefore, it is important to elucidate the clinical characteristics of these treated CRPC cases and their sensitivity to the currently used therapeutic agents. We aimed to examine the outcomes of metastatic castration-resistant prostate cancer following combined androgen blockade as initial therapy at our institution.

METHODS

Ninety-four patients who developed metastatic castration-resistant prostate cancer after hormonal treatment with combined nonsteroidal androgen receptor antagonists and continuous androgen deprivation therapy between January 2015 and December 2020 were included. The presence of visceral metastases, duration of efficacy of each treatment, and overall survival after castration-resistant prostate cancer were evaluated.

RESULTS

Patients with a longer duration of castration-resistant prostate cancer tended to have a longer response duration to subsequent enzalutamide administration (p = 0.003). Patients who achieved a 90% reduction in prostate-specific antigen levels with enzalutamide had a significantly better castration-resistant prostate cancer prognosis (p = 0.002). Meanwhile, those with visceral metastases at the time of castration-resistant prostate cancer diagnosis had a significantly poorer prognosis (p < 0.001). A positive correlation was observed between the treatment efficacy of abiraterone and taxanes for castration-resistant prostate cancer.

CONCLUSION

The study provides scientific evidence to support that patients with longer time to castration-resistant prostate cancer are more sensitive to enzalutamide, and the use of abiraterone between docetaxel and cabazitaxel has favorable prognostic impact. These findings provide instrumental evidence that can enable better treatment selection for prostate cancer patients.

The presence of lymph node metastases and time to castration resistance predict the therapeutic effect of enzalutamide for castration-resistant prostate cancer

BACKGROUND

Enzalutamide is effective against castration-resistant prostate cancer (CRPC). However, it is unclear which patients would benefit more from enzalutamide treatment. Here, we analyzed patients who received enzalutamide as first-line therapy for CRPC and evaluated the factors that predict treatment response and prognosis.

METHODS

We retrospectively analyzed 101 patients treated with enzalutamide for CRPC at our institution. As primary endpoints we regarded the prostate-specific antigen (PSA) response rate and PSA-progression-free survival (PSA-PFS) from the start of enzalutamide treatment. Laboratory and imaging data were analyzed to predict treatment efficacy.

RESULTS

PSA reductions of ≥ 50% and ≥ 90% were observed in 78 (77%) and 47 (47%) patients, respectively, compared with the baseline. During the follow-up period, 67 (66%) patients showed PSA progression, with a median PSA-PFS of 11 months. Moreover, 31 patients (31%) died, with a median overall survival of 64 months. On multivariate analysis, lymph node metastases at the start of enzalutamide treatment [odds ratio (OR) 0.0575, 95% confidence interval (CI) 0.0105-0.316, p = 0.0010] and time to CRPC (OR 0.177, 95% CI 0.0428-0.731, p = 0.0167] were associated with ≥ 90% PSA response. Lymph node metastases (hazard ratio [HR] 3.00, 95% CI 1.48-6.09, p = 0.0023) and time to CRPC (HR 1.84, 95% CI 1.02-3.30, p = 0.0419) were also predictors of PSA-PFS on a multivariate model.

CONCLUSIONS

Time to CRPC and lymph node metastasis were predictors of the PSA response rate and PSA-PFS.

Time to castration resistance is a novel prognostic factor of cancer-specific survival in patients with nonmetastatic castration-resistant prostate cancer

We aimed to identify prognostic factors of cancer-specific survival (CSS) in non-metastatic castration-resistant prostate cancer (M0CRPC) patients. The final analysis of this retrospective cohort included 82 patients who were diagnosed as M0CRPC between 1998 and 2018 at the University of Tokyo Hospital. CRPC was defined as prostate-specific antigen (PSA) progression (increased PSA ≥ 25% and ≥ 2 ng/mL above the nadir or detection of a metastatic lesion). The median value of age and PSA at the time of CRPC were 76 (range 55-94) years and 2.84 (range 2.04-22.5) ng/mL, respectively. The median follow-up time from CRPC diagnosis was 38 (range 3-188) months. The prognostic factors of CSS were 'PSA doubling time (PSADT) ≤ 3 months', 'time to CRPC diagnosis from the start of androgen deprivation therapy (TTCRPC) ≤ 12 months', of which TTCRPC was a novel risk factor of CSS. In the multivariate analysis, 'PSADT ≤ 3 months' and TTCRPC ≤ 12 months' remained as statistically significant predictors of CSS. Novel risk stratification was developed based on the number of these risk factors. The high-risk group showed a hazard ratio of 4.416 (95% confidence interval 1.701-11.47, C-index = 0.727).

Evaluation and Effectiveness of Clinical Trials with Hormone Therapy in the Treatment of Prostate Cancer

Background: Prostate cancer is currently the most common malignant tumour in men. Research on hormone therapy advances is necessary because, unfortunately, some tumours are not organ-confined. Objective: To review and analyse the current state of evidence regarding clinical trials with neoadjuvant or adjuvant hormone therapy for prostate cancer and determine the contribution of these trials to the clinical practice. Methods: A critical systematic analysis of hormone therapy clinical trials for prostate cancer in the American Society of Clinical Oncology (ASCO) 2022 official database was carried out and following the Cochrane Handbook for Systematic Reviews ofInterventions, a meta-analysis of random effects and standard mean descriptive statistics were performed. Groups: Group A = Neoadjuvant (n = 53) clinical trials and Group B = Adjuvant (n = 73) clinical hormone therapy. Variables: Phase of the trial, modality of primary treatment, investigated intervention or drug, molecular targets, trial length, sponsors and collaborators, country/countries of trial development, estimated enrolment, assignment of patients, intervention and masking model, trial purpose, related articles, the average number of studied patients, and conclusive results in clinical practice. Results: A total of 7.15% of the studies were in phase I, 14.28% between phase I-phase II, 52.38% in phase II, 0.23% between phase II-phase III and 23.80% in phase III. In the neoadjuvant group, enzalutamide and abiraterone were more frequently used, the androgen receptor was more frequently investigated as a molecular target. In the adjuvant group, abiraterone and prednisone were more frequently used and the androgen receptor and cytochrome P450 were more frequently investigated. The mean number of articles related to each trial was 5.26 (SD 3.15, 1–10). In 47.27% of the published articles directly related to the trials, the investigated treatment was superior to the standard treatment. Adjuvant investigated drugs showed more superiority (52.22%) than neoadjuvant drugs (41.33%). Conclusions: Only 41.33% of neoadjuvant studies and 52.22% of adjuvant studies show conclusive results of superiority for the proposed therapeutic strategies. About a third of related scientific publications that transfer the results to clinical practice did not report conclusive results for either neoadjuvant (32%) or adjuvant (37.78%) therapy.

Time on treatment with abiraterone and enzalutamide in the Patient-overview Prostate Cancer in The National Prostate Cancer Register of Sweden

BACKGROUND

There are little and inconsistent data from clinical practice on time on treatment with the androgen receptor-targeted drugs (ART) abiraterone and enzalutamide in men with metastatic castration-resistant prostate cancer (mCRPC). We assessed time on treatment with ART and investigated predictors of time on treatment.

MATERIAL AND METHODS

Time on treatment with ART in men with mCRPC in the patient-overview prostate cancer (PPC), a subregister of the National Prostate Cancer Register (NPCR) of Sweden, was assessed by use of Kaplan-Meier plots and Cox regression. To assess the representativity of PPC for time on treatment, a comparison was made with all men in NPCR who had a filling for ART in the Prescribed Drug Registry.

RESULTS

2038 men in PPC received ART between 2015 and 2019. Median time on treatment in chemo-naïve men was 10.8 (95% confidence interval 9.1-13.1) months for abiraterone and 14.1 (13.5-15.5) for enzalutamide. After the use of docetaxel, time on treatment was 8.2 (6.5-12.4) months for abiraterone and 11.1 (9.8-12.6) for enzalutamide. Predictors of a long time on treatment with ART were long duration of ADT prior to ART, low serum levels of PSA at start of ART, absence of visceral metastasis, good performance status, and no prior use of docetaxel. PPC captured 2522/6337 (40%) of all men in NPCR who had filled a prescription for ART. Based on fillings in the Prescribed Drug Registry, men in PPC had a slightly longer median time on treatment with ART compared to all men in NPCR, 9.6 (9.1-10.3) vs. 8.6 (6.3-9.1) months.

CONCLUSIONS

Time on treatment in clinical practice was similar or shorter than that in published RCTs, due to older age, poorer performance status and more comorbidities.

Predictive factors of survival outcomes in first-line therapy for metastatic castration-resistant prostate cancer

OBJECTIVES

To investigate predictive factors of survival of metastatic castration-resistant prostate cancer patients undergoing first-line treatment with androgen receptor pathway inhibitors or docetaxel.

METHODS

Japanese patients with metastatic castration-resistant prostate cancer treated with androgen receptor pathway inhibitor or docetaxel between 2008 and 2018 were included. The differential impact of various clinicopathological factors on the outcome, including progression-free survival and overall survival, was compared between treatment with androgen receptor pathway inhibitor and docetaxel.

RESULTS

Of 254 patients with metastatic castration-resistant prostate cancer, 119 (46.9%) and 135 (53.2%) were treated with androgen receptor pathway inhibitor and docetaxel, respectively. The multivariate analysis showed that androgen receptor pathway inhibitor was an independent prognostic factor for better progression-free survival (hazard ratio 0.62, 95% confidence interval 0.42-0.92, P = 0.016) and overall survival (hazard ratio 0.61, 95% confidence interval 0.41-0.93, P = 0.021), compared with docetaxel. Pretreatment prostate-specific antigen levels and time to castration-resistant prostate cancer were differentially associated with progression-free survival and overall survival between androgen receptor pathway inhibitor or docetaxel. In patients who presented <6 months to castration-resistant prostate cancer, progression-free survival was shorter in those treated with androgen receptor pathway inhibitor (median 1.1 months, 95% confidence interval 0.2-2.8 months) compared with those who received docetaxel (median 5.0 months, 95% confidence interval 1.8-6.7 months; P = 0.014).

CONCLUSIONS

First-line therapy with androgen receptor pathway inhibitor is associated with a better prognosis when compared with docetaxel, even after adjustment for prognostic factors. However, a shorter time to castration-resistant prostate cancer is associated with better progression-free survival for patients receiving docetaxel, suggesting that docetaxel is the preferred option for patients with a shorter time to castration-resistant prostate cancer.

Optimal Sequencing and Predictive Biomarkers in Patients with Advanced Prostate Cancer

The treatment landscape of advanced prostate cancer has completely changed during the last decades. Chemotherapy (docetaxel, cabazitaxel), androgen-receptor signaling inhibitors (ARSi) (abiraterone acetate, enzalutamide), and radium-223 have revolutionized the management of metastatic castration-resistant prostate cancer (mCRPC). Lutetium-177-PSMA-617 is also going to become another treatment option for these patients. In addition, docetaxel, abiraterone acetate, apalutamide, enzalutamide, and radiotherapy to primary tumor have demonstrated the ability to significantly prolong the survival of patients with metastatic hormone-sensitive prostate cancer (mHSPC). Finally, apalutamide, enzalutamide, and darolutamide have recently provided impactful data in patients with nonmetastatic castration-resistant disease (nmCRPC). However, which is the best treatment sequence for patients with advanced prostate cancer? This comprehensive review aims at discussing the available literature data to identify the optimal sequencing approaches in patients with prostate cancer at different disease stages. Our work also highlights the potential impact of predictive biomarkers in treatment sequencing and exploring the role of specific agents (i.e., olaparib, rucaparib, talazoparib, niraparib, and ipatasertib) in biomarker-selected populations of patients with prostate cancer (i.e., those harboring alterations in DNA damage and response genes or PTEN).

Prognostic role of the duration of response to androgen deprivation therapy in patients with metastatic castration resistant prostate cancer treated with enzalutamide or abiraterone acetate

BACKGROUND

Our retrospective study aims to evaluate the prognostic role of duration of response to androgen deprivation therapy (ADT) in metastatic castration resistant prostate cancer (mCRPC) patients treated with enzalutamide (E) or abiraterone acetate (AA).

MATERIALS AND METHODS

Data about ADT start and duration were available in 255 (82%) of 311 patients treated with AA or E. Patients were divided in three groups according to ADT response (group 1 [G1]: <12 months; group 2 [G2]: 12-36 months; group 3 [G3]: >36 months). Outcome measures were progression-free survival (PFS) and overall survival (OS).

RESULTS

Patients with longer ADT response had better OS (median 17.3 months G1, 19.9 months G2, 31.6 months G3; HR G3 vs G1 0.41, 95% CI 0.25-0.64; p = 0.001) and better PFS (median 5.9 months G1, 8.8 months G2, 11.7 months G3; HR G3 vs G1 0.41, 95% CI 0.41-0.27; p < 0001). In docetaxel-naive patients, median OS was 18.8 in G1, 35.2 in G2, and not reached in G3 (HR G3 vs G1 0.33, 95% CI 0.14-0.78; p = 0.038), median PFS was 7 months G1, 9.3 months G2, and 20 months G3 (HR G3 vs G1 0.31, 95% CI 0.15-0.62; p = 0.003). In postdocetaxel patients, median OS was 13.1 months in G1, 17.2 months in G2, and 21.4 months in G3 (HR G3 vs G1 0.52, 95% CI 0.29-0.94; p = 0.082), while median PFS was 5.2 months in G1, 6.8 months in G2, and 8.3 months in G3 (HR G3 vs G1 0.54, 95% CI 0.32-0.91; p = 0.067).

CONCLUSIONS

Duration of ADT response is an independent prognostic factor of outcome with AA or E.

Efficacy and safety of abiraterone acetate plus prednisolone in patients with early metastatic castration-resistant prostate cancer who failed first-line androgen-deprivation therapy: a single-arm, phase 4 study

Aim

The aim was to evaluate the efficacy and safety of abiraterone acetate plus prednisolone in patients with chemotherapy-naïve early metastatic castration-resistant prostate cancer who failed first-line androgen deprivation therapy.

Methods

Patients with early metastatic castration-resistant prostate cancer with confirmed prostate-specific antigen progression within 1-year or prostate-specific antigen progression without having normal prostate-specific antigen level (<4.0 ng/mL) during first-line androgen deprivation therapy were enrolled and administered abiraterone acetate (1000 mg) plus prednisolone (10 mg). A minimum of 48 patients were required according to Simon’s minimax design. The primary endpoint was prostate-specific antigen response rate (≥50% prostate-specific antigen decline by 12 weeks), secondary endpoints included prostate-specific antigen progression-free survival and overall survival. Safety parameters were also assessed.

Results

For efficacy, 49/50 patients were evaluable. Median age was 73 (range: 55–86) years. The median duration of initial androgen deprivation therapy was 32.4 (range: 13.4–84.1) weeks and 48 patients experienced prostate-specific antigen progression within 1-year after initiation of androgen deprivation therapy. prostate-specific antigen response rate was 55.1% (95% confidence interval: 40.2%–69.3%), median prostate-specific antigen–progression-free survival was 24.1 weeks, and median overall survival was 102.9 weeks (95% confidence interval: 64.86 not estimable [NE]). Most common adverse event was nasopharyngitis (15/50 patients, 30.0%). The most common ≥grade 3 adverse event was alanine aminotransferase increased (6/50 patients, 12.0%).

Conclusions

Abiraterone acetate plus prednisolone demonstrated a high prostate-specific antigen response rate of 55.1%, suggesting tumor growth still depends on androgen synthesis in patients with early metastatic castration-resistant prostate cancer. However, prostate-specific antigen–progression-free survival was shorter than that reported in previous studies. Considering the benefit–risk profile, abiraterone acetate plus prednisolone would be a beneficial treatment option for patients with chemotherapy-naive metastatic prostate cancer who show early castration resistance.

Efficacy and tolerability of current treatments for hormone-refractory prostate cancer patients with visceral metastases

Aim: To assess the efficacy and tolerability of the first-line treatment options for hormone-refractory prostate cancer patients with visceral metastases. Materials & methods: The records of 191 patients diagnosed with hormone-refractory prostate cancer with visceral metastases were analyzed retrospectively. Results: Docetaxel was administered to 61.2% (n = 117), abiraterone to 14.2% (n = 27) and enzalutamide to 9.4% (n = 18) as the first-line treatment. The median survival of the patients receiving docetaxel, abiraterone and enzalutamide as the first-line treatment during the hormone-refractory period was 15 (95% Cl: 12.9-17) months, 6 (95% Cl: 1.8-10.1) months and 11 (95% Cl: 0.9-23.1) months (p = 0.038), respectively. Conclusion: The present study established a statistically significant difference in favor of docetaxel in terms of overall survival and progression-free survival.

Preclinical Models in Prostate Cancer: Resistance to AR Targeting Therapies in Prostate Cancer

Prostate cancer is an androgen-driven tumor. Different prostate cancer therapies consequently focus on blocking the androgen receptor pathway. Clinical studies reported tumor resistance mechanisms by reactivating and bypassing the androgen pathway. Preclinical models allowed the identification, confirmation, and thorough study of these pathways. This review looks into the current and future role of preclinical models to understand resistance to androgen receptor-targeted therapies. Increasing knowledge on this resistance will greatly improve insights into tumor pathophysiology and future treatment strategies in prostate cancer.

Impact of Time to Castration Resistance on Cytoreductive Radiotherapy in Metastatic Castration-Resistant Prostate Cancer

Background

The role of local radiotherapy in metastatic castration-resistant prostate cancer (mCRPC) remains undefined. This study aimed to identify the value of local radiotherapy and potential candidates for mCRPC.

Methods

A total of 215 patients with mCRPC treated with or without cytoreductive radiotherapy (CRT) between June 2011 and February 2019 were analyzed. Overall survival (OS) was calculated from the onset of mCRPC. The receiver-operating characteristic (ROC) curve was used to find the cutoff point for time to castration resistance (TCR).

Results

One-hundred and fifty-five (72.1%) patients received abiraterone after mCRPC, and 54 (25.1%) patients received CRT. The median TCR was 14.9 months. After a median follow-up of 31.7 months, the median OS was 33.3 months. The Eastern Cooperative Oncology Group (ECOG) performance scores 0-1, oligometastases, abiraterone after mCRPC, CRT, and TCR ≥9 months were independent prognostic factors for better OS. Stratified analyses showed improved survival when CRT was applied to patients treated with abiraterone (HR 0.44; 95% CI 0.23-0.83; P = 0.012) and TCR ≥9 months (HR 0.39; 95% CI 0.21-0.74; P = 0.004). The percentage of PSA response after radiotherapy was higher in patients with TCR ≥9 months compared to those with TCR <9 months. No grade 3 or worse adverse events after radiotherapy were reported.

Conclusions

ECOG performance score, oligometastases, abiraterone application, TCR and CRT were independent prognostic factors for OS in patients with mCRPC. Patients with a short duration of response to primary androgen deprivation therapy were less likely to benefit from CRT.

[Early- vs. late-onset treatment using abiraterone acetate plus prednisone in chemo-naïve, asymptomatic or mildly symptomatic patients with metastatic CRPC after androgen deprivation therapy]

BACKGROUND

 Abiraterone acetate (AA) is a prodrug of abiraterone, which is an irreversible inhibitor of 17α-hydroxylase/C17, 20-lyase. Since 2011, abiraterone acetate has been available in combination with prednisone/prednisolone (AA + P) for the treatment of metastatic castration-resistant prostate cancer (mCRPC) after pre-treatment with docetaxel, and since 2012 for the treatment of chemotherapy-naïve asymptomatic or mildly symptomatic mCRPC patients. A revision of the guidelines of the European Association of Urology in 2014 redefining castration resistance gave rise to the question of when the treatment of mCRPC with abiraterone acetate plus prednisone should be initiated after prior hormone treatment and how successful it would be. This led us to observe an early-onset AA + P therapy cohort (EC) and a late-onset therapy cohort (LC) of patients.

PATIENTS AND METHODS

 We designed a combined retrospective and prospective, multicentre, non-interventional two-cohort study to obtain data on the effectiveness and safety of an early-onset AA + P therapy in mCRPC patients in the clinical routine compared to a late therapy onset. The EC comprised patients who received AA + P immediately after castration resistance without a prior first-generation antiandrogen such as bicalutamide or flutamide. The LC included patients who, after castration resistance had occurred, started treatment with AA + P only after unsuccessful treatment with a first-generation antiandrogen. Patients with mCRPC who received AA + P therapy according to the physician's routine clinical practice decision were considered. The patients were consecutively included in the study on the basis of their medical records, with the treatment decision having been made independently of and before patient enrolment. Patients were documented or followed from the beginning of AA + P therapy until the start of a carcinoma-specific systemic follow-up therapy (retrospectively if before and prospectively if after start of data collection). Effectiveness analyses were done for all patients with at least two AA + P administrations and safety analyses for all treated patients.

RESULTS

 Of the 159 patients included, 44 received early therapy and 105 received later therapy with AA + P. 10 patients could not be clearly assigned and were summarised in a third cohort (missed early-onset therapy assignment; MEC). 56/159 patients (35.2 %) were still alive at study start and 103/159 patients (64.8 %) had already deceased (31/44 [70.5 %] in EC, 64/105 [61.0 %] in LC, and 8/10 [80.0 %] in MEC). 24/159 patients (15.1 %) were documented both retrospectively and prospectively. The median duration of AA + P treatment was 11.3 months for EC, 12.0 months for LC, and 8.3 months for MEC patients. The median time to next systemic cancer therapy or death was 12.3 months for EC and 12.8 months for LC patients (p = 0.2820). The median time to the next systemic cancer therapy alone (i. e. without the event 'death') was 22.7 months for EC and 23.3 months for LC patients (p = 0.5995). Median overall survival (OS) was 22.3 months for EC and 39.2 months for LC patients (p = 0.0232). The incidence of serious adverse events (SAEs) was low. SAEs occurred in 3/44 EC (6.8 %), 4/105 LC (3.8 %), and 1/10 MEC patients (10.0 %). One SAE in EC and one in LC resulted in death.

CONCLUSIONS

 In contrast to the new definition of castration resistance, AA + P was still more frequently used in daily clinical practice during the study observation period in patients treated with antiandrogens of the first generation after occurrence of castration resistance. Nevertheless, AA + P therapy appears to be effective and well tolerated during clinical routine in mCRPC patients. A comparison of the study results with earlier 'real-world' studies, however, has to take limiting factors into account. The observed difference in median overall survival might be explained by the imbalance of baseline characteristics between both cohorts with regard to number of patients, patients already deceased at start of documentation, patients with visceral metastases and patients with opioids at start of AA + P. For these reasons, patients in the EC initially might have had a poorer prognosis. A prospective randomised and controlled clinical trial would therefore be necessary to assess a possible difference in overall survival and response of the AA + P treatment with respect to therapy onset.

Is the duration of castration resistance predictive for sequential treatment responses in the metastatic castration-resistant prostate cancer setting?

OBJECTIVE

Prostate cancer is the second leading cause of cancer death in men. Androgen deprivation therapy (ADT) has been the primary therapeutic approach for treatment of prostate cancer. However,nearly all patients develop the castration-resistant disease . We evaluated real-world data with abiraterone and enzalutamide treatment. By this data, we aimed to analyze whether that prior short response to ADT could predict response to subsequent therapy with androgen receptor axis targeted agent (ARATA).

MATERIAL AND METHOD

We collected data from two cancer centers, 151 consecutive patients with treated abiraterone or enzalutamide in the first line of metastatic castration resistant prostat cancer (mCRPC) setting were included. The patients who received docetaxel in castration naive setting is also included. Time to castration resistance (TTCR) was defined as the duration from the initial to failure of primary ADT.

RESULTS

Patients with treated ARATA were divided into two groups according to the time to castration resistance (TTCR). Patients who became resistant to ADT up to one year had a median PFS of 6.6 months, compared to median PFS of 13.3 months for patients who responded ADT for more than 1 year. (p = 0.002). In the post-docetaxel setting, median PFS is 12.6 months of patients with treated ARATA who had TTCR for more than one year, and median PFS is 6.6 months in those who had TTCR less than one year (p = 0.007).Univariate and multivariate analyses were performed to determine the clinical factors on ARATA outcomes. Eastern Cooperative Oncology Group (ECOG) performance status(PS), median prostate-specific antigen(PSA) and time to CRPC were significantly predicted outcomes of ARATA on multivariate analysis.

CONCLUSION

TTCR is also a predictor for PFS of the patients who were treated ARATA both whole cohort and post-docetaxel.

Emerging promising biomarkers for treatment decision in metastatic castration-resistant prostate cancer

Prostate cancer is one of the most common causes of death in males. Even if treatment is often of curative intent in early stages of the disease, up to 50% of patients relapse after primary therapy. Moreover, 10% to 15% of patients present in a primary metastatic stage of disease. In the past years the treatment landscape of metastatic castration-resistant prostate cancer expanded due to the development of second-generation antiandrogens (abiraterone acetate, enzalutamide), chemotherapeutic agents and radium-223. With the availability of several therapeutic lines, we are now confronted with the problem of choosing the most suitable therapy in each state of disease. As often observed in clinical routine, prostate specific antigen is not sufficient for early prediction of a therapy response. Furthermore, biomarkers for prediction of the optimal first-line therapy are badly needed in order to avoid primary resistance. Therefore, the present short review article gives an overview of currently available clinical and preclinical biomarkers for treatment response to metastatic castration-resistant prostate cancer therapeutic agents with the aim of providing support for a personalized decision-making process in everyday use.

Predictors of resistance to abiraterone acetate or enzalutamide in patients with metastatic castration-resistant prostate cancer in post-docetaxel setting: a single-center cohort study

Treatment with abiraterone acetate or enzalutamide is one of the approved approaches in men with metastatic castration-resistant prostate cancer (mCRPC) in the post-docetaxel setting. However, a significant fraction of patients do not respond to treatment, and we aimed to determine their characteristics. From April 2015 to May 2019, 71 patients with mCRPC were treated with abiraterone acetate (N = 34) or enzalutamide (N = 37) at our institution. Resistance to treatment was defined as radiological or scintigraphic progression within 3 months, as documented at the first control. After a median follow-up of 14.9 months, resistance was detected in 22 patients (31%). Many of the baseline characteristics differed between responders and nonresponders but did not serve as predictors with clinically acceptable certainty. To overcome this, the resistance score was defined as the number of positive out of the following six predictors: Most patients with resistance and a few responders had >3 positive predictors. Therefore, by using a cutoff of four positive predictors, the resistance score showed both a high sensitivity of 82% [57-96%; 95% confidence interval (CI)] and a specificity of 88% (74-96%; 95% CI). The proposed resistance score integrates the diagnostic performances of multiple predictors and may serve to decide which patients with mCRPC should be offered treatments other than hormonal therapy.

Successful management of prostate cancer with bulky pelvic lymph node metastases after rapid development of castration-resistant prostate cancer: a case report with review of the literature

The rapid development of castration-resistant prostate cancer (CRPC) is a poor prognostic sign for loco-regionally advanced prostate cancer. Non-metastatic CRPC (nmCRPC) with bulky regional lymph node metastases is extremely rare and difficult to treat clinically without reported case. We present a case of a 72-year-old man with locally advanced prostate cancer with bulky lymph node metastases (53 mm × 77 mm × 67 mm), developing nmCRPC after 9-month ADT treatment. Immunohistochemistry (IHC) tests found partially positive MUC1 and negative BRCA1 expression in the initial biopsy specimens. Next-generation sequence analysis on the blood specimen after CRPC predicted a good tolerance to docetaxel. According to the multidisciplinary team recommendations, he was administrated docetaxel 75 mg/m² on day 1 every 21 days for 6 cycles, and subsequently radiotherapy, with the delivery of a total dose of 67.5, 60-65 and 47.5 Gy in 25 fractions to the prostate, the enlarged lymph nodes and the whole pelvis respectively. Over a follow-up of 50 months, his disease has achieved good local control and he is alive without evidence of distant metastases or late adverse events. This case highlights individualized and multimodal therapy of intensification of systemic therapy and timely application of radiotherapy in such rare condition.

Prostate-specific membrane antigen in circulating tumor cells is a new poor prognostic marker for castration-resistant prostate cancer

The aim of this study is to elucidate the clinical significance of prostate-specific membrane antigen (PSMA) expression in circulating tumor cells (CTCs) from castration-resistant prostate cancer (CRPC) patients. We analyzed a total of 203 CTC samples from 79 CRPC patients to investigate the proportion of positive mRNA expressions at different treatment phases. Among them, we elected to focus on specimens from 56 CRPC patients who progressed on therapy and were subsequently provided a new treatment (treatment-switch cohort). In this cohort, we investigated the association between PSMA expression in CTCs and treatment response. CTCs were detected in 55/79 patients and median serum PSA in CTC-positive patients was 67.0 ng/ml. In the treatment-switch cohort of 56 patients, 20 patients were positive for PSMA in CTCs. PSMA expression was inversely associated with percentage of change in prostate-specific antigen (PSA). The median PSA progression-free survival and overall survival were significantly shorter in the PSMA-positive cohort. Furthermore, PSMA expression was predictive of poorer treatment response, shorter PSA progression-free survival and overall survival. PSMA expression in circulating tumor cells may be a novel poor prognostic marker for CRPC.

The Evolving Systemic Treatment Landscape for Patients with Advanced Prostate Cancer

Prostate cancer (PC) is a major health issue in developed countries, with, on the one hand, men suffering from sequelae related to unnecessary treatment of non-lethal PC, and, on the other hand, still dying because of advanced PC that progresses to castration-resistant disease. Systemic treatment is the mainstay of therapy of castration-resistant PC (CRPC). To date, a multitude of systemic agents have been tested and many of these have failed to provide a clinically meaningful benefit in CRPC, while others have been approved by the US Food and Drug Administration and/or the European Medicines Agency, including antiandrogen hormonal drugs (abiraterone, enzalutamide, apalutamide), chemotherapy (docetaxel and cabazitaxel), immunotherapy (Sipuleucel-T), and radiopharmaceutical (Radium-223) agents. In this review, systemic treatments regarded as most likely to have an impact in clinical practice are presented and discussed. In addition to the pivotal clinical studies, selected retrospective and non-randomized clinical trials are also discussed if deemed to have an impact on clinical practice or future research. A comprehensive appraisal of the expanding landscape of systemic therapies for advanced PC is provided from an expert perspective, with a focus on novel classification and diagnostic tools that have been paving the way for the development of precision medicine in PC.

Plasma Androgen Receptor Copy Number Status at Emergence of Metastatic Castration-Resistant Prostate Cancer: A Pooled Multicohort Analysis

PURPOSE

Increases in androgen receptor (AR) copy number (CN) can be detected in plasma DNA when patients develop metastatic castration-resistant prostate cancer. We aim to evaluate the association between AR CN as a continuous variable and clinical outcome.

PATIENTS AND METHODS

PCR2023 was an international, multi-institution, open-label, phase II study of abiraterone acetate plus prednisolone (AAP) or abiraterone acetate plus dexamethasone that included plasma AR assessment as a predefined exploratory secondary end point. Plasma AR CN data (ClinicalTrials.gov identifier: NCT01867710) from this study (n = 133) were pooled with data from the following three other cohorts: cohort A, which was treated with either AAP or enzalutamide (n = 73); the PREMIERE trial (ClinicalTrials.gov identifier: NCT02288936) of biomarkers for enzalutamide (n = 94); and a phase II trial from British Columbia (ClinicalTrials.gov identifier: NCT02125357) that randomly assigned men to either AAP or enzalutamide (n = 201). The primary outcome measures for the biomarker analysis were overall survival and progression-free survival.

RESULTS

Using multivariable fractional polynomials analysis using Cox regression models, a nonlinear relationship between plasma AR CN and outcome was identified for overall survival, where initially for small incremental gains in CN there was a large added hazard ratio that plateaued at higher CN. The CN cut point associated with the highest local hazard ratio was 1.92. A similar nonlinear association was observed with progression-free survival. In an exploratory analysis of PCR2023, the time from start of long-term androgen-deprivation therapy to start of AAP or abiraterone acetate plus dexamethasone was significantly shorter in patients with plasma AR CN of 1.92 or greater than patients with plasma AR CN of less than 1.92 (43 v 130 weeks, respectively; P = .005). This was confirmed in cohort A (P = .003), the PREMIERE cohort (P = .03), and the British Colombia cohort (P = .003).

CONCLUSION

Patients with metastatic castration-resistant prostate cancer can be dichotomized by a plasma AR CN cut point of 1.92. Plasma AR CN value of 1.92 or greater identifies aggressive disease that is poorly responsive to AR targeting and is associated with a prior short response to primary androgen-deprivation therapy.

Values of alkaline phosphatase at the diagnosis of castration resistance and response to primary androgen deprivation therapy as predictors of subsequent metastasis in non-metastatic castration-resistant prostate cancer

PURPOSE

Among various therapeutic options available for metastatic castration-resistant prostate cancer (mCRPC), only apalutamide and enzalutamide have shown evidences of improved metastasis-free survival (MFS) for non-metastatic castration-resistant prostate cancer (nmCRPC). However, there is a paucity of evidence to indicate who may be targeted for aggressive therapy among patients with nmCRPC. The objectives of this retrospective study were to explore predictors of metastasis in patients with nmCRPC and to identify a subpopulation of patients with nmCRPC who may benefit from aggressive therapy.

METHODS

A total of 115 patients with CRPC who had no metastasis detected at the time of diagnosis of CRPC were included in this retrospective study. All patients were treated at Jikei University and its affiliated hospitals. The primary outcome measure was MFS from the time of diagnosis of CRPC. Predictors of MFS were also explored with a multivariate Cox hazard model.

RESULTS

The median observation period after diagnosis of CRPC was 30 months (range 2-143 months). Kaplan-Meier analysis revealed a median MFS of 76. Multivariate analysis demonstrated that low alkaline phosphatase (ALP) values at diagnosis of CRPC and favorable response to primary androgen deprivation therapy (ADT) were significant predictors of longer MFS (P = 0.011, and 0.031, respectively).

CONCLUSIONS

Results of this study suggest that high ALP values at diagnosis of CRPC and poor response to primary ADT may predict the propensity of metastasis in patients with nmCRPC. Further prospective studies will be required enrolling more patients to confirm our findings.

The β2-Adrenergic Receptor Is a Molecular Switch for Neuroendocrine Transdifferentiation of Prostate Cancer Cells

The incidence of treatment-related neuroendocrine prostate cancer (t-NEPC) is rising as more potent drugs targeting the androgen signaling axis are clinically implemented. Neuroendocrine transdifferentiation (NEtD), an putative initial step in t-NEPC development, is induced by androgen-deprivation therapy (ADT) or anti-androgens, and by activation of the β₂-adrenergic receptor (ADRB2) in prostate cancer cell lines. Thus, understanding whether ADRB2 is involved in ADT-initiated NEtD may assist in developing treatment strategies that can prevent or reverse t-NEPC emergence, thereby prolonging therapeutic responses. Here we found that in primary, treatment-naïve prostate cancers, ADRB2 mRNA was positively correlated with expression of luminal differentiation markers, and ADRB2 protein levels were inversely correlated with Gleason grade. ADRB2 mRNA was upregulated in metastatic prostate cancer, and progressively downregulated during ADT and t-NEPC emergence. In androgen-deprivated medium, high ADRB2 was required for LNCaP cells to undergo NEtD, measured as increased neurite outgrowth and expression of neuron differentiation and neuroendocrine genes. ADRB2 overexpression induced a neuroendocrine-like morphology in both androgen receptor (AR)-positive and -negative prostate cancer cell lines. ADRB2 downregulation in LNCaP cells increased canonical Wnt signaling, and GSK3α/β inhibition reduced the expression of neuron differentiation and neuroendocrine genes. In LNCaP xenografts, more pronounced castration-induced NEtD was observed in tumors derived from high than low ADRB2 cells. In conclusion, high ADRB2 expression is required for ADT-induced NEtD, characterized by ADRB2 downregulation and t-NEPC emergence. IMPLICATIONS: This data suggest a potential application of β-blockers to prevent cancer cells committed to a neuroendocrine lineage from evolving into t-NEPC.

Prognostic significance of antihypertensive agents in men with castration-resistant prostate cancer

PURPOSE

Comorbidity with hypertension (HTN) may affect the outcome of castration-resistant prostate cancer (CRPC). In this study, we evaluated the prognostic impact of antihypertensive agents in patients with CRPC treated with androgen receptor axis-targeting (ARAT) agents or docetaxel chemotherapy.

PATIENTS AND METHODS

This study included 156 Japanese men with CRPC who were treated with ARAT agents (n = 85) or docetaxel (n = 71) at our hospital between 2008 and 2017. Associations between clinicopathological factors, HTN status, progression-free survival (PFS) and overall survival (OS) were evaluated by univariate and multivariate analysis.

RESULTS

When adjusted for age, prostate-specific antigen levels at pretreatment, Gleason score, and clinical M-stage, comorbid HTN was significantly associated with better OS (hazards ratio, 95% confidence interval: 0.41, 0.21-0.77; P = 0.0051), but not with PFS (hazards ratio, 95% confidence interval: 0.64, 0.38-1.11; P = 0.11) in patients treated with ARAT agent. However, HTN was not associated with PFS or OS for patients treated with docetaxel.

CONCLUSIONS

Use of antihypertensive agents has prognostic significance for patients with CRPC treated with ARAT agent, but not docetaxel.

Higher Serum Testosterone Levels Associated with Favorable Prognosis in Enzalutamide- and Abiraterone-Treated Castration-Resistant Prostate Cancer

Testosterone plays a significant role in maintaining the tumor microenvironment. The role of the target serum testosterone (TST) level in enzalutamide- (Enza) and abiraterone (Abi)-treated castration-resistant prostate cancer (CRPC) patients was studied. In total, 107 patients treated with Enza and/or Abi at Chiba University Hospital and affiliated hospitals were studied. The relationships between progression-free survival (PFS), overall survival (OS), and clinical factors were studied by Cox proportional hazard and Kaplan–Meier models. In the Abi and Enza groups overall, TST ≥ 13 ng/dL (median) (Hazard Ratio (HR) 0.43, p = 0.0032) remained an independent prognostic factor for PFS. In the Enza group, TST ≥ 13 ng/dL (median) was found to be a significant prognostic factor (HR 0.28, p = 0.0044), while, in the Abi group, TST ≥ 12 ng/dL (median) was not significant (HR 0.40, p = 0.0891). TST showed significant correlation with PFS periods (r = 0. 32, p = 0.0067), whereas, for OS, TST ≥ 13 ng/dL (median) showed no significant difference in the Abi and Enza groups overall. According to Kaplan–Meier analysis, a longer PFS at first-line therapy showed a favorable prognosis in the Enza group (p = 0.0429), while no difference was observed in the Abi group (p = 0.6051). The TST level and PFS of first-line therapy may be considered when determining the treatment strategy for CRPC patients.

Abiraterone acetate plus prednisone for the Management of Metastatic Castration-Resistant Prostate Cancer (mCRPC) without prior use of chemotherapy: report from a large, international, real-world retrospective cohort study

Background

With the recent introduction of novel treatment options, real-world data from patients with metastatic castration-resistant prostate cancer (mCRPC) are required to better understand the impact on routine clinical practice. This study primarily aimed to describe the time to treatment failure (TTF) of mCRPC patients treated with abiraterone acetate plus prednisone or the corticosteroid of choice (AAP) in the pre-chemotherapy setting. Other relevant outcomes, clinical and treatment characteristics of these patients were also evaluated.

Methods

This retrospective, observational study collected data from chemotherapy-naïve mCRPC patients treated with AAP from four European countries. Kaplan-Meier curves were used to estimate TTF, progression-free survival (PFS), and time to first skeletal-related event. The impact of baseline characteristics on TTF and PFS was explored using univariate and multivariate Cox proportional hazard models. Log-rank test was used to assess the potential role of duration of response to ADT in predicting response to AAP treatment.

Results

Data from 481 eligible patients (Belgium: 68; France: 61; Germany: 150; UK: 202) were analysed. At AAP initiation, the median age of patients was 75.0 years (interquartile range [IQR]: 69.0–81.0), and the median PSA was 56.2 ng/mL (IQR: 22.2–133.1), with over 50% of patients presenting an ECOG score of 0 or 1. Visceral metastases were present in 7.5% of patients; an exclusion criterion in the COU-AA-302 clinical trial. The median TTF with AAP was 10.0 months (95%CI: 9.2–11.1) and the median PFS was 10.8 months (95%CI: 9.6–11.8). Shorter TTF was significantly associated with higher ALP (> 119 units/L), higher PSA (> 56.2 ng/mL), or poorer ECOG PS scores at AAP initiation (p < 0.05). Patients with longer duration of response to ADT (≥12 months) presented longer TTF and longer time to progression (p < 0.0001).

Conclusions

This European real-world study provides valuable insights into the characteristics, treatment, and outcomes of chemotherapy-naïve patients with mCRPC who received AAP in routine clinical practice. Treatment effectiveness of AAP in the real-world is maintained despite patients having poorer clinical features at initiation than those observed in the COU-AA-302 trial population.

Electronic supplementary material

The online version of this article (10.1186/s12885-019-5280-6) contains supplementary material, which is available to authorized users.

Abiraterone acetate for chemotherapy-naive metastatic castration-resistant prostate cancer: a single-centre prospective study of efficacy, safety, and prognostic factors

Background

To evaluate the efficacy and safety of abiraterone acetate (AA) plus prednisone compared with prednisone alone in Asian patients with chemotherapy-naive metastatic castration-resistant prostate cancer (mCRPC), and to identify predictive factors.

Methods

We reviewed the medical records of 60 patients with chemotherapy-naive mCRPC at Renji Hospital who were treated with AA plus prednisone (n = 43) or prednisone alone (n = 17). All patients were assessed for prostate-specific antigen (PSA) response, PSA progression-free survival (PSA PFS), radiographic progression-free survival (rPFS), and overall survival (OS). The ability of several parameters to predict PSA PFS, rPFS, and OS was studied.

Results

The median follow-up time was 14.0 months (range 7.0–18.5 months), at which time 19 death events had been reported: 11 in the AA + prednisone group and 8 in the prednisone group. The AA + prednisone group had significantly longer median PSA PFS (10.3 vs 3.0 months, P < 0.001), rPFS (13.9 vs 3.9 months, P < 0.001), and OS (23.3 vs 17.5 months, P = 0.016) than the prednisone-alone group. The most frequently reported grade 3 or 4 adverse event in both the AA + prednisone and prednisone-alone groups was elevated alanine aminotransferase level in 5 of 43 patients (11.6%) and 2 of 17 patients (11.8%), respectively. No adverse events led to discontinuation of therapy. In multivariate analysis, time from androgen deprivation therapy (ADT) to castration resistance of ≤18 months was a determinant of shorter OS (P = 0.007).

Conclusions

These results support the favourable safety and efficacy profile of AA for the treatment of Asian patients with chemotherapy-naive mCRPC. Longer duration of ADT response was significantly associated with longer survival.

Electronic supplementary material

The online version of this article (10.1186/s12894-018-0416-6) contains supplementary material, which is available to authorized users.

Serum testosterone level as possible predictive marker in androgen receptor axis-targeting agents and taxane chemotherapies for castration-resistant prostate cancer

PURPOSE

Currently, several therapeutic options for castration-resistant prostate cancer (CRPC) are available, for which predictive biomarkers have not been established. Therefore, we aimed to reveal the association between pretreatment serum testosterone level and antitumor outcomes when treated with androgen receptor axis-targeting agents and taxane chemotherapies for CRPC.

PATIENTS AND METHODS

The present study included Japanese patients with metastatic prostate cancer whose serum testosterone levels during androgen-deprivation therapy were available. The antitumor outcomes when treated with enzalutamide, abiraterone, docetaxel, and cabazitaxel with clinicopathological parameters including serum testosterone levels during androgen-deprivation therapy, as well as prognoses including progression-free survival and overall survival, were examined.

RESULTS

Progression-free survival among men with higher serum testosterone level was superior to that among men with lower serum testosterone level when treated with enzalutamide. On the contrary, progression-free survival and overall survival among men with higher serum testosterone level were significantly inferior to those among men with lower serum testosterone level when treated with docetaxel and cabazitaxel, respectively.

CONCLUSIONS

The present study indicated distinct prognostic values of serum testosterone level when treated with androgen receptor axis-targeting agent and taxane chemotherapy for CRPC, suggesting that serum testosterone level may be useful predictive biomarker to navigate the appropriate therapy in patients with CRPC.

Sequencing of Taxanes and New Androgen-targeted Therapies in Metastatic Castration-resistant Prostate Cancer: Results of the International Multicentre Retrospective CATS Database

BACKGROUND

The optimal sequence of life-extending therapies in metastatic castration-resistant prostate cancer (mCRPC) is unknown.

OBJECTIVE

To evaluate outcomes among mCRPC patients treated with docetaxel (DOC), cabazitaxel (CABA), and a novel androgen receptor-targeted agent (ART; abiraterone acetate or enzalutamide) according to three different sequences.

DESIGN, SETTING, AND PARTICIPANTS

Data from 669 consecutive mCRPC patients were retrospectively collected between November 2012 and October 2016.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The primary endpoint was the prostate-specific antigen (PSA) response (decrease ≥50% from baseline) to each therapy. Secondary endpoints included best clinical benefit, time to PSA progression, radiological progression-free survival (rPFS), overall survival (OS), and toxicity.

RESULTS AND LIMITATIONS

A total of 158 patients received DOC→CABA→ART (group 1), 456 received DOC→ART→CABA (group 2), and 55 received ART→DOC→CABA (group 3). At baseline, PSA progression only and Gleason <8 were more common in group 3. PSA response on DOC was lower in group 3 than in other groups (p=0.02) and PSA response on CABA was higher in the second than in the third line (p=0.001). In Group 3, rPFS on ART (6.6 mo) and DOC (9.2 mo) was also shorter than in the other groups. OS calculated from the first life-extending therapy reached 34.8, 35.8, and 28.9 mo in groups 1, 2 and 3, respectively (p=0.007). Toxicity was comparable between the arms. The main limitations of the trial are its retrospective design and the low number of patients in group 3.

CONCLUSIONS

In this retrospective trial, sequencing of DOC, CABA, and one ART, was associated with median OS of up to 35.8 mo. CABA seemed to retain its activity regardless of treatment sequence. DOC activity after ART appeared to be reduced, but the data are insufficient to conclude that cross-resistance occurs.

PATIENT SUMMARY

The order of drugs administered to patients with metastatic castration-resistant prostate cancer could impact their efficacy, with cabazitaxel appearing to retain its activity whatever the therapeutic sequence.

ATM‑JAK‑PD‑L1 signaling pathway inhibition decreases EMT and metastasis of androgen‑independent prostate cancer

Castration-resistant prostate cancer (CRPC), also known as androgen-independent prostate cancer, frequently develops local and distant metastases, the underlying mechanisms of which remain undetermined. In the present study, surgical specimens obtained from patients with clinical prostate cancer were investigated, and it was revealed that the expression levels of ataxia telangiectasia mutated kinase (ATM) were significantly enhanced in prostate cancer tissues isolated from patients with CRPC compared with from patients with hormone-dependent prostate cancer. CRPC C4-2 and CWR22Rv1 cells lines were subsequently selected to establish prostate cancer models, and ATM knockout cells were established via lentivirus infection. The results of the present study demonstrated that the migration and epithelial-mesenchymal transition (EMT) of ATM knockout cells were significantly decreased, which suggested that ATM is closely associated with CRPC cell migration and EMT. To further investigate the mechanisms underlying this process, programmed cell death 1 ligand 1 (PD-L1) expression was investigated in ATM knockout cells. In addition, inhibitors of Janus kinase (JAK) and signal transducer and activator of transcription 3 (STAT3; Stattic) were added to C4-2-Sc and CWR22Rv1-Sc cells, and the results demonstrated that PD-L1 expression was significantly decreased following the addition of JAK inhibitor 1; however, no significant change was observed following the addition of Stattic. Furthermore, a PD-L1 antibody and JAK inhibitor 1 were added to C4-2-Sc and CWR22Rv1-Sc cells, and it was revealed that cell migration ability was significantly decreased and the expression of EMT-associated markers was effectively reversed. The results of the present study suggested that via inhibition of the ATM-JAK-PD-L1 signaling pathway, EMT, metastasis and progression of CRPC may be effectively suppressed, which may represent a novel therapeutic approach for targeted therapy for patients with CRPC.

Current treatment strategies for advanced prostate cancer

During the past decade, treatment strategies for patients with advanced prostate cancer involving stage IV (T4N0M0, N1M0 or M1) hormone-sensitive prostate cancer and recurrent prostate cancer after treatment with curative intent, as well as castration-resistant prostate cancer, have extensively evolved with the introduction and approval of several new agents including sipuleucel-T, radium-223, abiraterone, enzalutamide and cabazitaxel, all of which have shown significant improvement on overall survival. The appropriate use of these agents and the proper sequencing of these agents are still not optimized. The results of several recently reported randomized controlled trials and retrospective studies could assist in developing a treatment strategy for advanced prostate cancer. In addition, prospective studies and molecular characterization of tumors to address these issues are ongoing.

Predictors of long-term response to abiraterone in patients with metastastic castration-resistant prostate cancer: a retrospective cohort study

We aimed to identify clinical predictors of long-term response to abiraterone (defined as >12 months drug exposure) in a retrospective cohort of metastatic castration-resistant prostate cancer patients treated in post-docetaxel setting at 24 Italian centers. The Cox proportional hazards model was used to analyze the association between clinical features and the duration of drug exposure. Results were expressed as hazard ratios (HR) with associated 95% confidence intervals (CI). A total of 143 patients met the inclusion criteria. Their median age was 73 years, median Gleason score 8 and median abiraterone exposure 20 months. At the univariate analysis, a significant correlation with the duration of abiraterone exposure was found for Gleason score (HR 0.82, 95% CI 0.71-0.96; p=0.012), PSA (HR 1.10, 95% CI 1.03-1.18; p=0.08) and lactic dehydrogenase levels (HR 1.22, 95% CI 1.02-1.46; p=0.027), while the association between lower alkaline phosphatase levels and treatment duration was marginally significant (HR 1.07, 95% CI 0.99-1.16; p=0.074). Only PSA and Gleason score were predictive of long-term treatment duration in the multivariate analysis. No other clinical factors resulted to be predictive of sustained response to abiraterone, including metastatic disease at diagnosis and visceral disease, suggesting that all subgroups of patients may derive a substantial clinical benefit from abiraterone treatment. These findings need to be validated in prospective, larger studies.

Duration of response to first androgen deprivation therapy, time to castration resistance prostate cancer, and outcome of metastatic castration resistance prostate cancer patients treated with abiraterone acetate

Abiraterone acetate (AA) demonstrated its efficacy in the treatment of patients with metastatic castration resistance prostate cancer (mCRPC) in predocetaxel and postdocetaxel setting. However, we learn from pivotal studies that forms of primary and acquired resistance to this drug exist. Patient selection becomes so crucial to optimize treatment results. Potential predictive biomarkers have been identified but are not yet validated. In this scenario, clinical features and disease characteristics may still be of value in selecting patients for different treatments. The objective of this retrospective study was to assess whether or not a correlation between duration of response to first androgen deprivation therapy (ADT), time to castration-resistant prostate cancer (TTCRPC), and outcome of AA therapy exists. A retrospective analysis of clinical data of mCRPC patients treated with AA at two Italian cancer centers was carried out. The Kaplan-Meier method and Cox proportional hazard model were used to analyze survival data. Correlation between median duration of response to first ADT or median TTCRPC and the outcome of patients treated with AA was analyzed. From January 2015 to November 2015, data of 59 patients with mCRPC were collected. We observed no differences in patient's median progression-free survival (PFS) and biochemical progression-free survival (bPFS), according to both median duration of response to first-line ADT (duration of first ADT<13 months: median PFS and bPFS were 11 and 5 months, respectively; duration of ADT≥13 months: median PFS and bPFS were 9 and 6 months, respectively) and median TTCRPC (TTCRPC<28 months: median PFS and bPFS were 8 and 5 months, respectively; TTCRPC≥28 months: median PFS and bPFS were 10 and 9 months, respectively). Overall survival, in the same group, did not differ between patients with a duration of response to first ADT over or under 13 months (P=0.90) but in patients with a TTCRPC of 28 months or more, there was a trend toward longer survival than patients with TTCRPC less than 28 months (5-year overall survival was 74 vs. 50%; P=0.14). The duration of response to first-line ADT and the TTCRPC showed no significant association with outcome of AA therapy in patients with mCRPC. However, large prospective trials are desirable to confirm these data.

First-line management of metastatic castrate-resistant prostate cancer patients: Audit of real-life practices

BACKGROUND

No reliable guidelines are available for choosing the best option between docetaxel and new hormonal therapies (NHTs) (i.e., abiraterone and enzalutamide) in first-line therapy for metastatic castration-resistant prostate cancer (mCRPC) patients. We performed an audit of real-life practices.

METHODS

We built an online questionnaire and distributed it with the help of French oncology networks. This questionnaire was sent to 481 physicians who treat patients with mCRPC. All of the answers were declarative, individual, and anonymized. A descriptive analysis was done. A univariate logistic regression analysis was performed for the criteria of choice between docetaxel and NHTs.

RESULTS

From March to July 2015, 109/481 physicians (22.6%) completed the questionnaire. The selection criteria for initially choosing docetaxel were as follows: presence of visceral metastases (79.8%), heavy tumor burden (68.8%), aggressive tumor disease (66.1%), and short-term efficacy of castration (66.1%). The selection criteria for initially choosing NHTs were as follows: long-term efficacy of castration (66.1%), higher age (67.9%), low tumor grade (56.9%), and absence of symptoms (54.1%). With docetaxel, the first tumor assessment was typically performed after three (1-6) cycles, including prostate-specific antigen (PSA) testing (96.3%), a thoraco-abdominopelvic CT scan (68.8%), and bone scintigraphy (59.6%). With NHTs, tumor assessment was mainly performed after 3 months of treatment (1-6) and included PSA testing, a thoraco-abdominopelvic CT, and bone scintigraphy in 90.8%, 61.5%, and 63.3% of cases, respectively.

CONCLUSIONS

This is the first study assessing real-life practices among physicians who treat patients with mCRPC. These practices were found to be homogeneous.

Recent advances in genitourinary tumors: A review focused on biology and systemic treatment

Updated information published up to 2016 regarding major advances in renal cancer, bladder cancer, and prostate cancer is here presented. Based on an ever better understanding of the genetic and molecular alterations that govern the initial pathogenic mechanisms of tumor oncogenesis, an improvement in the characterization and treatment of urologic tumors has been achieved in the past year. According to the Cancer Genome Atlas (ATLAS) project, alterations in the MET pathway are characteristics of type 1 papillary renal cell carcinomas, and activation of NRF2-ARE pathway is associated with the biologically distinct type 2. While sunitinib and pazopanib continue to be the standard first-line treatment in metastatic renal cell carcinoma of clear cell histology, nivolumab and cabozantinib are now the agents of choice in the second-line setting. In relation to urothelial bladder carcinoma, new potential molecular targets such as FGFR3, PI3K/AKT, RTK/RAS, CDKN2A, ARIDIA, ERBB2 have been identified. Response to adjuvant cisplatin-based chemotherapy appears to be related to basal, luminal, and p53-like intrinsic subtypes. A phase II study with eribulin and a maintenance phase II trial with vinflunine have shown promising results. Similarly, the use of the check point inhibitors in advanced disease is likely to revolutionize the management of patients who have progressed after cisplatin-based chemotherapy. In prostate cancer, seven mutually exclusive molecular subtypes have been identified by the TCGA project. Chemotherapy has been consolidated as a key treatment for castration-sensitive metastatic prostate cancer, and abiraterone, enzalutamide, cabazitaxel, and radium-223 remain standard therapeutic options for men with metastatic castration-resistant prostate cancer. All this progress will undoubtedly contribute to the development of new treatments and therapeutic strategies that will improve the survival and quality of life of our patients.

Understanding prostate-specific antigen dynamics in monitoring metastatic castration-resistant prostate cancer: implications for clinical practice

Availability of novel hormonal therapies as well as docetaxel and cabazitaxel treatment for metastatic castration-resistant prostate cancer (CRPC) has changed the outlook for this group of patients with improvements in progression-free survival and overall survival. Physicians often diagnose the progression of prostate cancer using serum prostate-specific antigen (PSA). However, serum PSA is not always correlated with the clinical status in CRPC. To evaluate the PSA dynamics with greater precision, understanding of the control of PSA and of the mechanisms of development of CRPC is needed. Moreover, it is necessary to use new hormonal therapies with an appropriate timing to optimally improve the prognosis and the QOL of the patients. In the present review, we ascertain the PSA dynamics and the mechanisms of the development of CRPC to assist in optimal utilization of the new treatments for mCRPC.

Safety and Antitumour Activity of ODM-201 (BAY-1841788) in Castration-resistant, CYP17 Inhibitor-naïve Prostate Cancer: Results from Extended Follow-up of the ARADES Trial

BACKGROUND

Patients with castration-resistant prostate cancer (CRPC) had extended responses to the androgen receptor antagonist ODM-201, in phase 1/2 studies.

OBJECTIVE

To evaluate the safety and antitumour activity of prolonged ODM-201 treatment in patients with CRPC.

DESIGN, SETTING, AND PARTICIPANTS

The ARADES trial was a multicentre phase 1 (dose escalation) and phase 2 (dose expansion) trial; 134 patients with CRPC were stratified by previous chemotherapy to receive ODM-201. This paper reports extended follow-up in CYP17 inhibitor (CYP17i)-naïve patients.

INTERVENTION

Patients (n=77) received oral ODM-201 twice daily at daily doses of 200-1800mg.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Safety, measured as the occurrence of adverse events (AEs), prostate-specific antigen (PSA), and radiographic progression.

RESULTS AND LIMITATIONS

The safety profile of extended ODM-201 treatment (median treatment duration 8.2 mo, 95% confidence interval [CI] 5.6-11.0) was consistent with that reported at the time of the original data cutoff in the main ARADES trial, with no unexpected safety concerns over time. The majority of AEs (61.1%) were mild (grade 1); the most common AE was fatigue/asthenia (35.1% of patients), with no clear relationship to ODM-201. Median time to PSA progression was 25.2 mo (95% CI 11.3-25.2) for chemotherapy-naïve men and not reached (NR; 95% CI 5.5-NR) for chemotherapy-pretreated patients; a trend for improved antitumour response was observed for chemotherapy-naïve patients. The median time to radiographic progression was longer for chemotherapy-naïve (14.0 mo, 95% CI 8.1-33.3) than for chemotherapy-pretreated (7.2 mo, 95% CI 2.7-11.0) patients.

CONCLUSIONS

Prolonged exposure to ODM-201 was well tolerated, with no additional safety concerns; disease suppression was sustained, especially in chemotherapy-naïve patients. These data support further development of ODM-201 in men with CYP17i-naïve CRPC.

PATIENT SUMMARY

Extended ODM-201 therapy was well tolerated, with beneficial antitumour activity in men with advanced prostate cancer, indicating that ODM-201 may represent a new active treatment for men with CRPC. This extension trial is registered at ClinicalTrials.gov (www.clinicaltrials.gov) under identification number NCT01429064.

The Natural History and Outcome Predictors of Metastatic Castration-resistant Prostate Cancer

CONTEXT

Biomarkers for the treatment of metastatic castration-resistant prostate cancer (mCRPC) are urgently needed by clinicians to facilitate treatment decisions.

OBJECTIVE

To review current prognostic and predictive biomarkers in mCRPC.

EVIDENCE ACQUISITION

We performed a nonsystematic review of the literature from 2004 to August 2016 by searching in Medline. Cross-matching references were used to search for additional articles. We reviewed clinical research and review articles written in the English language.

EVIDENCE SYNTHESIS

Nomograms of prognostic factors (eg, albumin, lactate dehydrogenase) enable clinicians to estimate the prognosis of men with mCRPC. These prognostic tools may aid with when to trigger treatment, therapeutic monitoring, and follow-up. However, validated predictive biomarkers in mCRPC are still lacking. Androgen receptor (AR) splice variants (ie, AR-V7), gene fusions, and point mutations determined using liquid biopsies such as circulating tumor cells (CTCs) or cell-free DNA (cfDNA) are promising biomarkers that are the subject of ongoing research. Patient biomarkers (eg, neutrophil-to-lymphocyte ratio) are readily available and come with no extra cost but need further validation before their implementation in clinical practice.

CONCLUSIONS

Determination of AR-V7 in CTCs is a big step towards a more personalized treatment approach in mCRPC. Genomic characterization of liquid biopsies such as CTCs, cfDNA, and circulating RNA are noninvasive tools to further personalize treatment in prostate cancer. Clinical parameters are readily available, but are derived from retrospective studies and should be interpreted with care. Only by conducting biomarker-driven studies, rather than large one-size-fits-all trials, will we be able to improve prostate cancer treatment.

PATIENT SUMMARY

Several biomarkers are currently under investigation that may predict which patients will respond to specific therapies in the future of metastatic castration-resistant prostate cancer treatment.

Predictors of duration of abiraterone acetate in men with castration-resistant prostate cancer

BACKGROUND

Androgen receptor signaling remains important in castration-resistant prostate cancer (CRPC) as demonstrated by the efficacy of abiraterone acetate (henceforth abiraterone) in phase III trials. Given that heterogeneous patient responses are observed, we sought to identify clinical factors associated with duration of abiraterone.

METHODS

We retrospectively identified patients with CRPC treated with abiraterone in our database. Patient characteristics and types and duration of prostate cancer (PC) therapies were analyzed. These parameters were analyzed with duration of abiraterone in univariate and multivariable analyses.

RESULTS

We identified 161 patients who had received abiraterone. All had received primary androgen-deprivation therapy (ADT), 86% prior secondary hormone therapy (SHT) and 33% prior chemotherapy. The median duration of primary ADT was 23 months, duration of SHT (excluding abiraterone) was 17 months and duration of chemotherapy was 8 months. We demonstrated that lower PSA at abiraterone initiation, longer primary ADT duration, no prior ketoconazole, no prior chemotherapy and longer chemotherapy duration were associated with a longer duration on abiraterone in univariate analysis. In multivariable analysis, duration of primary ADT (duration of abiraterone 9 versus 13 months for ⩽12 versus >12 months, P=0.03) and no use of prior chemotherapy (duration of abiraterone 16 versus 7 months for no versus yes prior chemotherapy, P<0.01) were associated with duration of abiraterone.

CONCLUSIONS

Several clinical parameters, including type and duration of prior therapy, are predictive of responsiveness to abiraterone. These parameters are logical and correlate with smaller disease burden or less exposure to PC therapies. This information can help physicians counsel patients about the potential durability of efficacy of abiraterone. Identifying predictive biomarkers that inform patient selection for therapy is critical to optimizing treatment outcomes.