Real‐world outcome with abiraterone acetate plus prednisone in Asian men with metastatic castrate‐resistant prostate cancer: The Singapore experience

Abstract

Introduction: Several small studies have reviewed the efficacy of abiraterone acetate plus prednisolone (AAP) in clinical practice outside a trial setting. We report the largest cohort study of clinical outcomes in metastatic castrate-resistant prostate cancer (mCRPC) patients treated with AAP in a multicenter multiracial clinical setting. Methods:A retrospective analysis on mCRPC patients treated at four tertiary hospitals in Singapore from 2012 to 2017 was conducted. Disease characteristics, treatment outcomes, and adverse events were retrieved from electronic medical records. Primary clinical end-point was overall survival (OS). A subset analysis of patients with various variables and OS curves were generated using the Kaplan-Meier method and compared using the log-rank test. Results:Out of 200 patients with mCRPC treated with AAP, 163 (81.5%) patients were chemonaïve (CN) and 37 (18.5%) patients were postchemotherapy (PC), with the median age of 68 (34-87) and 65 (52-80) years, respectively. Median OS was 20.0 (95% CI, 18.3-22.9) and 10.5 months (95% CI, 1.1-40.5) for CN and PC cohorts, respectively. A subset analysis of 108 patients showed a significantly longer OS in patients who had prior ADT for more than 12 months in CN patients (P < 0.001). Incidences of G3/G4 events were around 6.6%; most common side effect being hypertension with an incidence of 2.4%. Conclusions: Treatment of CN and PC patients with AAP was associated with a comparable OSand progression-free survival to the reported series. Patients who were responsive to prior ADT of 12 months or more were associated with an improved OS. K E Y W O R D S abiraterone acetate, efficacy, metastatic castrate resistant prostate cancer, overall survival 1 INTRODUCTION Androgen deprivation therapy (ADT) is the mainstay of treatment for metastatic prostate cancer. 1 Since 2012, novel anti-androgens like abiraterone acetate plus prednisone/prednisolone (AAP) or enzalutamide have been available in Singapore as a treatment option in the metastatic castrate-resistant prostate cancer (mCRPC) either prior to or after docetaxel. AA, is a prodrug of abiraterone, a specific inhibitor of CYP17 enzyme leading to persistent androgen biosynthesis inhibition. 1 Updated analysis of the COU-AA-302 and COU-AA-301 studies where AAP was randomized against placebo and prednisone in the chemotherapy naïve (CN) and postchemotherapy (PC) setting showed a significant improvement in median overall survival (mOS) of 34.7 versus 30.3 months (hazard ratio [HR] = 0.81; 95% Asia-Pac J Clin Oncol. 2020;16:75-79. c

Real-world experience of abiraterone acetate plus prednisone in chemotherapy-naive patients with metastatic castration-resistant prostate cancer: long-term results of the prospective ABItude study

“…The favorable results of first-line abiraterone in men with mCRPC emerged in previous relatively small retrospective real-life investigations 26 , 27 , 28 , 29 , 30 are here confirmed in a prospective large study with long follow-up.…”

Real-World Data on Outcomes in Metastatic Castrate-Resistant Prostate Cancer Patients Treated With Abiraterone or Enzalutamide: A Regional Experience

“…This can have impact on survival outcomes. A subset analysis in Chan et al of chemotherapy naive patients with an ECOG 2-4 showed a poorer OS and PFS (12). Similarly, Boegemann et al (15), also showed that poorer ECOG was associated with shorter time to treatment failure.…”

“…Interestingly, similar to our study, real world studies on abiraterone in mCRPC have showed poorer outcomes than in the COU trials. A Singaporean retrospective audit (12) looking at abiraterone in the real world mCRPC population of 200 patients demonstrated a median OS of 20 months for men who were chemotherapy naïve and only 11.3 months for men who have had prior chemotherapy. The variability in patient population in terms of ECOG performance status and comorbidities in the real world are important factors to consider given the majority of patients with prostate cancer are elderly often with multiple medical problems.…”

Efficacy and safety of therapies for advanced prostate cancer in Asia: Evidence from a systematic literature review

“…Forty-seven were removed as duplicates due to overlapping among databases. After screening the titles and abstracts and then the full texts, 27 publications 17 – 43 were shortlisted. No additional studies were identified from the bibliographic search.…”

“…One RCT 26 and four real-world studies 29 – 33 contributed evidence for AAP in patients with mCRPC. In the RCT, Ye et al .…”