Abiraterone acetate versus nonsteroidal antiandrogen with androgen deprivation therapy for high-risk metastatic hormone-sensitive prostate cancer

Comparison of abiraterone, enzalutamide, and apalutamide for metastatic hormone-sensitive prostate cancer: A multicenter study

PURPOSE

We aimed to assess the differential efficacy and safety of androgen receptor pathway inhibitors (ARPI), such as abiraterone, enzalutamide, and apalutamide, in patients with metastatic hormone-sensitive prostate cancer (mHSPC) in a real-world practice setting.

METHODS

We retrospectively reviewed the records of consequent 668 patients with mHSPC treated with ARPI plus androgen deprivation therapy between September 2015 and December 2023. Based on the LATITUDE criteria, the comparison among abiraterone, enzalutamide, and apalutamide was exclusively conducted in high-risk patients. Prostate-specific antigen (PSA) responses such as the achievement of 95% and 99% PSA decline, overall survival (OS), cancer-specific survival (CSS), time to castration-resistant prostate cancer (CRPC), and the incidence of adverse events (AEs) were compared. All two-group comparisons relied on propensity score matching (PSM) to minimize the effect on possible confounders.

RESULTS

In total, 297 patients with high-risk mHSPC treated with abiraterone, 127 with enzalutamide, and 142 with apalutamide were compared. There were no differences in time to CRPC (p = 0.13), OS (p = 0.7), and CSS (p = 0.5) among the three ARPIs. No differences were observed in the achievement rates for 95% PSA decline at 3 months among the three ARPIs, while abiraterone was significantly better in 99% PSA decline achievement compared to apalutamide (72% vs. 57%, p = 0.003). The aforementioned oncologic outcomes were sustained even when performing PSM analyzes. Although skin rash for APA (34%) was the highest incidence of AEs, there were no differences in the rates of severe AEs across the three ARPIs. Enzalutamide resulted in the lowest treatment discontinuation rates (10%) other than disease progression compared to the other regimens.

CONCLUSIONS

Abiraterone, enzalutamide, and apalutamide have comparable oncologic outcomes in terms of OS, CSS, and time to CRPC in patients with high-risk mHSPC. Our data on differential treatment discontinuation rates, PSA response, and AE profiles can help guide clinical decision-making.

Efficacy of androgen receptor signaling inhibitors in combination with androgen deprivation therapy for castration-sensitive metastatic prostate cancer: a retrospective analysis in a Japanese cohort

BACKGROUND

This study aimed to evaluate the efficacy of androgen receptor signaling inhibitors (ARSIs) combined with androgen deprivation therapy (ADT) for treating castration-sensitive metastatic prostate cancer in Japanese patients, focusing on the effects on time to the development of castration-resistant prostate cancer (CRPC) and overall survival (OS).

METHODS

This retrospective muti-institutional analysis included 332 patients diagnosed with metastatic prostate cancer in Japan between 2018 and 2023. The patients were categorized into two groups: patients receiving ADT combined with ARSI (ARSI group) and those receiving ADT alone or with bicalutamide (ADT group). Data on demographics, treatments, and outcomes were compared using the Kaplan-Meier method with propensity score matching.

RESULTS

We found an increasing trend in ARSI use over time. The median time to CRPC was significantly longer in the ARSI group than in the ADT group (47.1 vs. 15.2 months, p < 0.001); however, no significant differences in OS were observed before or after propensity score matching. The 1-year-survival rate of patients in the ARSI group tended to be higher than that of patients in the ADT group in subgroups with high tumor volume (96.1% vs. 85.0%) and high Gleason grade (98.1% vs. 85.9%).

CONCLUSIONS

Adding ARSI to ADT extended the time to CRPC but did not significantly affect OS. However, it potentially suppressed the short-term risk of death in high-risk subgroups. This study highlights the need for further research to explore the characteristics of Japanese patients with metastatic prostate cancer in whom upfront ARSIs are effective.

Dose modification in enzalutamide and abiraterone plus prednisolone for castration-resistant prostate cancer: A subanalysis from the ENABLE study for PCa

BACKGROUND

A head-to-head comparison between enzalutamide (ENZ) and abiraterone plus prednisolone (ABI) revealed similar survival benefits for castration-resistant prostate cancer (CRPC) in the ENABLE study for PCa. Considering that a dose reduction of ENZ and ABI has demonstrated sufficient inhibitory ability of androgen receptor (AR) signaling, we analyzed the efficacy of modified doses of these agents in the ENABLE study for PCa.

METHODS

This investigator-initiated, multicenter, randomized controlled trial that was conducted in Japan analyzed the prespecified survival endpoints, prostate-specific antigen (PSA) response rate ( ≥50% decline from baseline), and safety profile in patients treated with modified doses (ENZ ≤ 120 mg/day, ABI ≤ 750 mg/day) compared with those treated with a standard dose (ENZ 160 mg/day, ABI 1000 mg/day) as a starting dose.

RESULTS

In total, 92 patients in each arm were treated and analyzed; 16 patients were treated with a modified dose in both the ENZ and ABI arms, respectively. Moreover, 32 patients treated with modified doses showed a significantly better time to PSA progression (TTPP) and overall survival (OS) compared with the 152 patients treated with a standard dose (HR 0.47, 95%CI 0.27-0.83, p = 0.0379, and HR 0.35, 95%CI 0.19-0.63, p = 0.0162). Despite a significantly longer TTPP in the modified ABI group than in the standard ABI group (HR 0.29, 95%CI 0.14-0.62, p = 0.0248), no significant difference was observed in the TTPP between the modified and standard ENZ groups (p = 0.5366). Furthermore, similar adverse event rates and grades were observed in each treatment dose group.

CONCLUSIONS

The modified doses of ABI showed better TTPP than the standard dose of ABI and may be a potential treatment option for CRPC patients; however, its mechanism is still unclear, although its ability to suppress AR signaling is equivalent to that of a standard dose.

Changes in the treatment landscape of metastatic hormone-sensitive prostate cancer following approval of upfront androgen receptor signaling inhibitors: A multicenter study

BACKGROUND

A multicenter database was utilized to examine the current treatment landscape and clinical outcomes among patients with metastatic hormone-sensitive prostate cancer (mHSPC) following approval of upfront androgen receptor signaling inhibitors (ARSIs).

METHODS

We retrospectively analyzed patients with mHSPC who commenced treatment between February 2018 and June 2023. The Kaplan-Meier method was used to assess oncological outcomes, including time to castration-resistant prostate cancer (CRPC), progression-free survival 2 (PFS2, duration from initial treatment to tumor progression during second-line treatment), cancer-specific survival (CSS), and overall survival (OS). Cox regression analyses were performed to determine the impact of treatment choices on oncological outcomes. In addition, the incidence rate of adverse events was assessed.

RESULTS

In total, 829 patients were analyzed; 42.5% received ARSIs with androgen deprivation therapy (ADT), 44.0% received combined androgen blockade (CAB), and 13.5% received ADT alone. Kaplan-Meier curves and multivariate Cox regression analyses indicated higher rates of CRPC and shorter PFS2 in patients treated with CAB versus ARSIs with ADT. By contrast, CSS and OS were not significantly different between the ARSI with ADT group and the CAB group. Grades 3-4 adverse events occurred in 1.9% of patients receiving CAB and 6.0% of those receiving ARSIs with ADT.

CONCLUSIONS

Initial treatment with ARSIs in combination with ADT resulted in a longer time to CRPC and longer PFS2 compared to CAB. Although CAB and ADT alone were associated with fewer adverse events, ARSIs with ADT should be considered a first-line treatment option given its superior oncological outcomes.

Novel Treatment Strategies for Low-Risk Metastatic Castration-Sensitive Prostate Cancer

BACKGROUND

The treatment strategy for metastatic castration-sensitive prostate cancer (mCSPC) has changed significantly in recent years. Based on various guidelines, an upfront androgen receptor signaling inhibitor (ARSI) is the first choice, but in patients of Asian descent, including Japanese patients, there are a certain number of cases in which androgen deprivation therapy (ADT) and CAB are more effective. If patients can be identified who show a marked response to ADT within 12 weeks after the initiation of ADT, which is the inclusion criterion for ARSI clinical trials targeting mCSPC, it would be valuable from an economic standpoint.

METHODS

A total of 218 patients with pure prostate adenocarcinoma and treated with ADT at the Kanazawa University Hospital between January 2000 and December 2020 were included in this study. As a risk classification for mCSPC, in addition to the LATITUDE and CHAARTED criteria, we used the castration-sensitive prostate cancer classification proposed by Kanazawa University (Canazawa), developed by the Department of Urology of Kanazawa University. The Canazawa classification was based on three factors: Gleason pattern 5, bone scan index (BSI) ≥ 1.5, and lactate dehydrogenase (LDH) ≥ 300 IU/L. It defined patients with one factor or less as low-risk and patients with two or three factors as high-risk. The overall survival (OS) and time to castration resistance (TTCR) were estimated retrospectively using the Kaplan-Meier method, and factors associated with TTCR were identified using univariate and multivariate analyses.

RESULTS

The median follow-up period was 40.4 months, the median OS period was 85.2 months, and the median TTCR period was 16.4 months. The Canazawa risk classification provided the clearest distinction between the OS and TTCR in mCSPC patients. Multivariate analysis revealed a decrease in PSA levels of <95% at 12 weeks after ADT initiation and was a predictor of short TTCR in low-risk, low-volume patients across all risk classifications.

CONCLUSION

The Canazawa classification differentiated the prognosis of mCSPC patients more clearly. A PSA reduction rate of <95% at 12 w after starting ADT in low-risk, low-volume patients of all risk classifications was significantly shorter than the TTCR. We propose a new treatment strategy, in which patients with low-risk mCSPC are treated with ADT and switched to ARSIs based on the rate of PSA reduction at 12 w.

Clinical Outcomes of Patients with High-risk Metastatic Hormone-naïve Prostate Cancer: A 3-year Interim Analysis of the Observational J-ROCK Study

BACKGROUND

Androgen deprivation therapy (ADT), administered alone, as combined androgen blockade (CAB) or as ADT plus androgen receptor signalling inhibitors (ARSIs) or ADT plus docetaxel, is the standard treatment for metastatic hormone-naïve prostate cancer (mHNPC) in Japanese real-world practice.

OBJECTIVE

To investigate treatment patterns and clinical outcomes in LATITUDE criteria high-risk mHNPC.

DESIGN, SETTING, AND PARTICIPANTS

The longitudinal, multicentre, J-ROCK registry study enrolled patients initiating ADT in Japan after May 2019, and categorised them as cohort 1 (ADT or CAB) or cohort 2 (ADT plus ARSIs or docetaxel).

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Prostate-specific antigen (PSA) response, progression-free survival (PFS), time to castrate-resistant prostate cancer (CRPC), overall survival (OS), and safety were evaluated. PFS, time to CRPC, and OS were estimated via the Kaplan-Meier method and between-cohort comparisons via multivariate Cox regression models.

RESULTS AND LIMITATIONS

In total, 974 patients were included (cohort 1: 38.1%, cohort 2: 61.9%). CAB was preferred (67.4%) to ADT alone in cohort 1, and abiraterone acetate plus prednisolone was used most frequently in cohort 2 (59.4%). The proportion of patients with ≥50%/≥90% PSA decline or who achieved PSA ≤0.2/≤0.1 ng/ml tended to be higher in cohort 2. PFS (adjusted hazard ratio 0.42; 95% confidence interval [CI] 0.31-0.55), time to CRPC (0.28; 95% CI 0.23-0.36), and OS (0.54; 95% CI 0.35-0.82) were longer in cohort 2. In cohorts 1 and 2, adverse drug reactions of special interest (ADRSIs) occurred in 1.3% and 15.1%, and fatal adverse events occurred in 1.9% and 1.7%, respectively. Limitations included nonrandomised design, varying time since marketing authorisation for ARSIs, and limited safety assessments.

CONCLUSIONS

ADT plus ARSIs or docetaxel was used more frequently to treat high-risk mHNPC than standard ADT/CAB and was associated with more favourable clinical outcomes. Although ADRSIs were reported more in cohort 2, the safety profile was considered tolerable.

PATIENT SUMMARY

Although many treatment options are available for high-risk metastatic prostate cancer, there are limited reports on real-world clinical experience with different therapies outside of the clinical trial setting. In this study, we compared clinical and safety outcomes with different treatment regimens, using a large series of patients with high-risk metastatic hormone-naïve prostate cancer across Japan. We found that androgen deprivation therapy in combination with newer androgen receptor signalling inhibitors resulted in improved response compared with androgen deprivation therapy alone or in combination with a first-generation antiandrogen.

The Geriatric Nutritional Risk Index Predicts Prognosis in Japanese Patients with LATITUDE High-Risk Metastatic Hormone-Sensitive Prostate Cancer: A Multi-Center Study

Malnutrition is associated with prognosis in cancer. The geriatric nutritional risk index (GNRI), based on the ratio of actual to ideal body weight and also serum albumin level, is a simple screening tool for assessing nutrition. We investigated the GNRI as a prognostic factor for oncological outcomes in patients with high-risk metastatic hormone-sensitive prostate cancer (mHSPC) using a Japanese multicenter cohort. This study included a total of 175 patients with LATITUDE high-risk mHSPC, of whom 102 had received androgen deprivation therapy (ADT) plus upfront abiraterone acetate, and 73 had received ADT plus bicalutamide (Bica), from 14 institutions associated with the Tokai Urologic Oncology Research Seminar. Patients were classified into GNRI-low (<98) or GNRI-high (≥98) groups. The GNRI was based on the body mass index and serum albumin level. Kaplan-Meier analysis revealed that the median overall survival (OS) of a GNRI-low group (median 33.7 months; 95% confidence interval [CI]: 26.2-not reached [NR]) was significantly worse than that of a GNRI-high group (median: NR; 95% CI: NR-NR; p < 0.001). Multivariate analysis identified Bica and low GNRI (<98) as independent prognostic factors for reduced times to both castration-resistant prostate cancer and OS, and, therefore, a poor prognosis. Our findings indicate the GNRI may be a practical prognostic indicator in the evaluation of survival outcomes in patients with LATITUDE high-risk mHSPC.

Combination of docetaxel versus nonsteroidal antiandrogen with androgen deprivation therapy for high-volume metastatic hormone-sensitive prostate cancer: a propensity score-matched analysis

PURPOSE

The aim of this study was to investigate the oncologic efficacy of combining docetaxel with androgen deprivation therapy (ADT) versus nonsteroidal antiandrogen (NSAA) with ADT in patients with high-volume metastatic hormone-sensitive prostate cancer (mHSPC) with focus on the effect of sequential therapy in a real-world clinical practice setting.

METHODS

The records of 382 patients who harbored high-volume mHSPC, based on the CHAARTED criteria, and had received ADT with either docetaxel (n = 92) or NSAA (bicalutamide) (n = 290) were retrospectively analyzed. The cohorts were matched by one-to-one propensity scores based on patient demographics. Overall survival (OS), cancer-specific survival (CSS), progression-free survival (PFS), including time to castration-resistant prostate cancer (CRPC), and time to second-line progression (PFS2) were compared. 2nd-line PFS defined as the time from CRPC diagnosis to progression after second-line therapy was also compared.

RESULTS

After matching, a total of 170 patients were retained: 85 patients treated with docetaxel + ADT and 85 patients treated with NSAA + ADT. The median OS and CSS for docetaxel + ADT versus NSAA + ADT were not reached (NR) vs. 49 months (p = 0.02) and NR vs. 55 months (p = 0.02), respectively. Median time to CRPC and PFS2 in patients treated with docetaxel + ADT was significantly longer compared to those treated with NSAA (22 vs. 12 months; p = 0.003 and, NR vs. 28 months; p < 0.001, respectively). There was no significant difference in 2nd-line PFS between the two groups.

CONCLUSIONS

Our analysis suggested that ADT with docetaxel significantly prolonged OS and CSS owing to a better time to CRPC and PFS2 in comparison to NSAA + ADT in high-volume mHSPC.

KIF14 mediates cabazitaxel-docetaxel cross-resistance in advanced prostate cancer by promoting AKT phosphorylation

Docetaxel is a first-line chemotherapy drug for castration-resistant prostate cancer (CRPC); yet, some CRPC patients develop docetaxel drug resistance. Cabazitaxel is approved in the post-docetaxel treatment setting. However, recent studies suggested cross-resistance between the development of drug resistance and current treatments. In this study, we used docetaxel-resistant cell lines DU145/DTX50 and PC-3/DTX30 to measure the responses to cabazitaxel. Our findings demonstrated that docetaxel resistance could lead to cross-resistance to cabazitaxel. After docetaxel-resistant cells were treated with cabazitaxel, transcriptome analysis was performed, and the results were analyzed in combination with survival analysis and correlation analysis with Gleason score to screen the cross-resistance genes. The continuously increased expression of kinesin family member 14 (KIF14) was identified as the main cause of cross-resistance to cabazitaxel in docetaxel-resistant cells. Silencing the expression of KIF14 could restore the sensitivity of resistant PCa cells to docetaxel and cabazitaxel, attenuate proliferation and promote apoptosis of the resistant PCa cells. Notably, the depressed expression of KIF14 inhibited the phosphorylation of Akt located downstream. In summary, KIF14 mediates the cross-resistance between docetaxel and cabazitaxel, and targeting KIF14 could be an effective measurement for reversing docetaxel or cabazitaxel chemotherapy failure or enhancing the anti-tumor effects of docetaxel or cabazitaxel.

Predictive factors for the efficacy of abiraterone acetate therapy in high-risk metastatic hormone-sensitive prostate cancer patients

PURPOSE

There is a discrepancy in the efficacy of abiraterone acetate for overall survival (OS) in patients with high-risk metastatic hormone-sensitive prostate cancer (mHSPC). This study aimed to identify predictive factors for the efficacy of abiraterone acetate for OS in high-risk mHSPC patients by analyzing them over a longer observation period.

METHODS

Five hundred high-risk mHSPC patients were retrospectively identified at our hospital and affiliated hospitals in the Kindai Oncology Study Group and Kyoto Prefectural University of Medicine Oncology Study Group between December 2013 and March 2022. Two hundred patients were treated with abiraterone acetate (1000 mg/day) plus prednisolone (5 mg/day) combined with androgen deprivation therapy (ADT). A total of 300 patients were treated with bicalutamide (80 mg/day) in combination with ADT.

RESULTS

OS was not significantly different between the two treatments in the overall cohort (p = 0.1643). In the subgroup without Gleason pattern 5 at the primary lesion, OS was significantly better in patients treated with abiraterone acetate than in those treated with bicalutamide (p = 0.0192). In the subgroup with Gleason pattern 5 at the primary lesion, no significant difference was found between the two treatments (p = 0.1799). Univariate and multivariate analyses in the subgroup without Gleason pattern 5 at the primary lesion suggested that abiraterone therapy may be an important and independent predictor of OS in high-risk mHSPC patients.

CONCLUSION

The presence of Gleason pattern 5 at the primary lesion may be a predictor for high-risk mHSPC patients who could benefit from abiraterone acetate treatment.

Factors influencing survival in metastatic castration resistant prostate cancer therapy

INTRODUCTION

The number of patients with metastatic castration resistant prostate cancer (mCRPC) is expecting to increase due to the long-life expectancy of those with advanced disease who are also more commonly diagnosed today because of stage migration. Several compounds are available for treating these patients.

AREAS COVERED

We reviewed currently available treatments for mCRPC, their mechanism of action and resistance and we explored possible predictors of treatment success useful to predict survival in mCRPC patients.

EXPERT OPINION

A combination of molecular, clinical, pathological, and imaging features is necessary to correctly estimate patients' risk of death. The combination of these biomarkers may allow clinicians to tailor treatments based on cancer history and patients' features. The search of predictive biomarkers remains an unmet medical need for most patients with mCRPC.

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.

Updates on Molecular and Biochemical Development and Progression of Prostate Cancer

Prostate cancer (PCa) represents the most commonly non-cutaneous diagnosed cancer in men worldwide and occupies a very wide area of preclinical and clinical research. Targeted therapy for any cancer depends on the understanding of the molecular bases and natural behaviour of the diseases. Despite the well-known effect of androgen deprivation on PCa, many patients develop resistance either for antiandrogen therapy or other new treatment modalities such as checkpoint inhibitors and chemotherapy. Comprehensive understanding of the development of PCa as well as of the mechanisms underlying its progression is mandatory to maximise the benefit of the current approved medications or to guide the future research for targeted therapy of PCa. The aim of this review was to provide updates on the most recent mechanisms regarding the development and the progression of PCa. According to the current understanding, future treatment strategies should include more predictive genetic and biomarker analysis to assign different patients to the expected most appropriate and effective treatment.