Assessment of the Safety of Glucocorticoid Regimens in Combination With Abiraterone Acetate for Metastatic Castration-Resistant Prostate Cancer: A Randomized, Open-label Phase 2 Study

Importance

Abiraterone acetate is combined with prednisone, 5 mg, twice daily for metastatic castration-resistant prostate cancer (mCRPC) and with prednisone, 5 mg, once daily for newly diagnosed, high-risk, metastatic castration-sensitive prostate cancer. Understanding the physiological effects of these and other regimens is important.

Objective

To evaluate the safety of abiraterone acetate with 4 glucocorticoid regimens.

Design, Setting, and Participants

Open-label, randomized clinical trial (1:1:1:1) of 164 men with mCRPC from 22 hospitals in 5 countries who were randomly assigned to 1 of 4 intervention groups between June 2013 and October 2014. Analyses were conducted from August 2017 to June 2018.

Interventions

Abiraterone acetate, 1000 mg, once daily with prednisone, 5 mg, twice daily (n = 41), 5 mg once daily (n = 41), 2.5 mg twice daily (n = 40), or dexamethasone, 0.5 mg, once daily (n = 42).

Main Outcomes and Measures

Primary end point was no mineralocorticoid excess (grade ≥1 hypokalemia or grade ≥2 hypertension) through 24 weeks (6 cycles) from treatment.

Results

Of 164 men (median [range] age, 70 [50-90] years) randomized to receive abiraterone acetate, 1000 mg, daily with prednisone, 5 mg, twice daily, once daily, or 2.5 mg twice daily, or dexamethasone, 0.5 mg, once daily, 24 (70.6%) of 34 patients (95% CI, 53.8%-83.2%), 14 (36.8%) of 38 patients (95% CI, 23.4%-52.7%), 21 (60.0%) of 35 patients (95% CI, 43.6%-74.4%), and 26 (70.3%) of 37 patients (95% CI, 54.2%-82.5%), respectively, had no mineralocorticoid excess. Plasma adrenocorticotrophic hormone and urinary mineralocorticoid metabolites after 8 weeks were higher with prednisone, 2.5 mg, twice daily and 5 mg once daily than with 5 mg twice daily or dexamethasone, 0.5 mg, once daily. The level of urinary glucocorticoid metabolites appeared higher in patients who did not meet the primary end point, regardless of glucocorticoid regimen. Total lean body mass decreased in the prednisone groups and total body fat increased in the prednisone, 5 mg, twice daily and dexamethasone groups. In the dexamethasone group, there was an increase in serum insulin and homeostatic model assessment of insulin resistance, while total bone mineral density decreased. In the prednisone, 5 mg, twice daily, 5 mg once daily, 2.5 mg twice daily, and dexamethasone groups, median radiographic progression-free survival was 18.5, 15.3, 12.8, and 26.6 months, respectively.

Conclusions and Relevance

Abiraterone acetate with prednisone, 5 mg, twice daily or dexamethasone, 0.5 mg, once daily met the prespecified threshold for the primary end point (95% CI excluded 50% mineralocorticoid excess); abiraterone acetate with prednisone, 5 mg, once daily or 2.5 mg twice daily did not meet the threshold. Abiraterone acetate in combination with dexamethasone appeared to be particularly active but may be associated with adverse metabolic consequences.

Trial Registration

ClinicalTrials.gov identifier: NCT01867710.

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.

Impact of abiraterone acetate plus prednisone or enzalutamide on fatigue and cognition in patients with metastatic castration-resistant prostate cancer: initial results from the observational AQUARiUS study

Introduction

Abiraterone acetate plus prednisone (AAP) and enzalutamide (ENZ) are commonly prescribed for metastatic castration-resistant prostate cancer (mCRPC). Data comparing their effects on patient-reported outcomes (PROs) from routine clinical practice are limited.

Methods

AQUARiUS (NCT02813408) is an ongoing, two-cohort, prospective, observational, non-randomised, multicentre, phase IV European study assessing the effects of AAP and ENZ on PROs in 211 patients with mCRPC over 12 months. Patients receive AAP or ENZ per routine clinical practice. Data on cognition, fatigue, pain and health-related quality of life are measured using the Functional Assessment of Cancer Therapy-Cognitive Function, Brief Fatigue Inventory-Short Form, Brief Pain Inventory-Short Form and European Organization for Research and Treatment of Cancer Quality of Life-C30 questionnaires, respectively.

Results

This 3-month analysis was conducted in 105 patients; 46 received AAP and 59 received ENZ. There were statistically significant differences in mean change from baseline favouring AAP over ENZ at months 1, 2 and 3 for perceived cognitive impairments and cognitive functioning. At each time-point, ENZ-treated patients had a significantly higher risk of experiencing clinically meaningful worsening in perceived cognitive impairments versus those receiving AAP.

Statistically significant differences in mean change from baseline favouring AAP over ENZ were seen for usual level of fatigue and fatigue interference at months 2 and 3 and for current fatigue and worse level of fatigue at month 3. Differences favouring AAP versus ENZ were seen for the fatigue scale of the QLQ-C30 questionnaire (months 1 and 3). There was a significantly higher risk of clinically meaningful worsening in usual level of fatigue with ENZ versus AAP at month 3.

No significant differences between cohorts were observed for pain (BPI-SF) at any time-point.

Conclusion

This analysis suggests more favourable outcomes with AAP versus ENZ for cognition and fatigue in the first 3 months of treatment initiation for mCRPC. These findings require confirmation from future analyses of data from AQUARiUS from a larger number of patients with a longer follow-up period.

Real-world treatment with abiraterone acetate in patients with chemotherapy-naive metastatic castration-resistant prostate cancer (mCRPC)

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Background: In the COU-AA-302 trial, abiraterone acetate plus prednisone (AAP) resulted in extension of radiographic progression-free survival (rPFS) and overall survival in chemotherapy-naïve mCRPC patients compared to prednisone alone. However, limited data on AAP treatment and outcomes is available in the real-world in this setting. The aim of this study is to describe the duration of AAP treatment in routine clinical practice in mCRPC patients prior to chemotherapy. Methods: The study was designed as a retrospective chart review of mCRPC patients identified through oncology and urology practice in Belgium, France, Germany and the UK. This first analysis reports baseline patient characteristics at AAP initiation for the first 224 patients. Treatment duration, PFS and rPFS were estimated using Kaplan-Meier curves. Potential factors associated with treatment duration were explored using the log-rank test. Results: Data from 224 mCRPC patients treated with AAP (Belgium: 67; Germany: 150; UK: 7; none from France) across 19 centres was considered in this initial analysis. At baseline, the median age was 75.5 years (interquartile range [IQR]: 69.0-82.0) and the median PSA level was 50.0 ng/mL (IQR: 21.0-121.0). Patients with visceral metastases (9.8%) and ECOG 2-3 (9.4%) were included in this study, in contrast to those included in the COU-AA-302 study. Median duration of AAP treatment was 11.6 months (95% confidence interval [CI]: 10.2-12.8), whilst median PFS and rPFS were 11.9 months (95% CI: 10.8-13.3) and 16.5 months (95% CI: 13.5-20.0), respectively. Reasons for discontinuing AAP involved PSA progression (52.2%), radiographic progression (38.9%), symptomatic progression (27.8%), non-toxic death (19.4%) and toxicity (2.2%). Treatment duration was significantly longer in mCRPC patients with either baseline ECOG status 0, lower PSA, alkaline phosphatase, aspartate aminotransferase, or lactate dehydrogenase levels (p < 0.05). Conclusions: The results of this study suggest similar treatment duration and rPFS for mCRPC patients in this real-life cohort with poorer clinical features compared to those observed in the COU-AA-302 trial population.