CUA 2017: Impact of Abiraterone Acetate in Post-Docetaxel Setting on the Survival of Metastatic Castration-Resistant Prostate Cancer Patients: A Population-Based Study in Quebec

Toronto, Ontario ( Abiraterone acetate (Abi) is a novel steroidal CYP17A inhibitor that is approved for use for patients with metastatic castration-resistant prostate cancer (CRPC). The COU-AA-301 study1 established its efficacy in a post-docetaxel setting, and ultimately, it was shown to be efficacious in men prior to chemotherapy treatment. Recent results from ASCO 2017 have now demonstrated its efficacy even in hormone-naïve metastatic prostate cancer, when given in conjunction with androgen deprivation therapy (ADT).

In this poster, the authors evaluate the efficacy of Abi in Quebec for its original indication – post-docetaxel therapy for mCRPC. Approved in 2012, they analyzed retrospectively a Quebec cohort using a Quebec public healthcare administrative database. The cohort consisted of mCRPC patients receiving abiraterone from 2012‒2013 (n=303). The abiraterone group was stratified into abiraterone post-chemotherapy (n=99) and abiraterone without chemotherapy (n=204, unfit for chemotherapy and qualified for abiraterone with the “exception patient” measure). The median age was 75 years for the abiraterone post-chemotherapy group and 80 years for the abiraterone “exception patient” group.

They found the median survival of these groups to be 12 and 14 months, respectively. Risk of death was similar in the abiraterone post-chemotherapy and abiraterone “exception patient” groups, either in an unadjusted or adjusted analysis (hazard ratio [HR] 0.89; 95% confidence interval [CI] 0.57‒1.38).

The take-home message from this study is that it essentially validates the COU-AA-301 study results in a real world population. However, their “exception patient” group represents a cohort similar to the COU-AA-302 group, and they found similar results in that cohort as well. 

While it does not provide any new information, it does establish the efficacy of Abi in a real-world Canadian population.

Limitations / Discussion Points:
1. No clinical information (PSA, ECOG status, testosterone levels, symptom measurement) available. 

2. No identification of precise date of entry into mCRPC stage, so it wasn’t possible to clinically similar mCRPC with whom to match the patients. 

Presented By: Alice Dragomir, PhD, MSc, McGill University, Montreal, Quebec

Co-Authors: Joice Rocha, PhD; Marie Vanhuyse, MD; Fabio L Cury, MD; Jason Hu, BSc; Noemie Prevost, MSc; Armen G Aprikian, MD
Institution: McGill University, Montreal, Quebec  

Written By: Thenappan Chandrasekar, MD, Clinical Fellow, University of Toronto   Twitter: @tchandra_uromd at the  72nd Canadian Urological Association Annual Meeting - June 24 - 27, 2017 - Toronto, Ontario, Canada


1. Abiraterone acetate for treatment of metastatic castration-resistant prostate cancer: final overall survival analysis of the COU-AA-301 randomised, double-blind, placebo-controlled phase 3 study. Fizazi K, Scher HI, Molina A, Logothetis CJ, Chi KN, Jones RJ, Staffurth JN, North S, Vogelzang NJ, Saad F, Mainwaring P, Harland S, Goodman OB Jr, Sternberg CN, Li JH, Kheoh T, Haqq CM, de Bono JS; COU-AA-301 Investigators. Lancet Oncol. 2012 Oct;13(10):983-92. doi: 10.1016/S1470-2045(12)70379-0. Epub 2012 Sep 18. Erratum in: Lancet Oncol. 2012 Nov;13(11):e464. Lancet Oncol. 2014 Aug;15(9):e365.