A multicentre analysis of abiraterone acetate in Canadian patients with metastatic castration resistant prostate cancer

  • Ravinder Clayton Tom Baker Cancer Centre Calgary, AB
  • Jackson Wu Tom Baker Cancer Centre Calgary, AB
  • Daniel Y Heng Tom Baker Cancer Centre Calgary, AB
  • Scott A North Cross Cancer Institute Edmonton, AB
  • Urban Emmenegger Odette Cancer Centre Toronto, ON
  • Sebastien Hotte Juravinski Cancer Centre Hamilton, ON
  • Kim Chi BC Cancer Agency Vancouver, BC
  • Rob Zielinski BC Cancer Agency Vancouver, BC
  • Humaid Al-Shamsi Juravinski Cancer Centre Hamilton, ON
  • Leo Chen BC Cancer Agency Vancouver, BC
  • Bernhard Eigl BC Cancer Agency Vancouver, BC
Keywords: Abiraterone, Prostate Cancer

Abstract

Introducton: The COU-AA-301 trial showed that abiraterone acetate (abiraterone), an oral cytochrome p450 CYP17 inhibitor, improved survival for men with metastatic castration-resistant prostate cancer (mCRPC) progressing after docetaxel. To better understand the non-clinical trial experience with abiraterone, we undertook a multicentre retrospective analysis of Canadian mCRPC patients treated with abiraterone.

Methods: Consecutive patients with mCRPC who received abiraterone post-docetaxel were identified using centralized pharmacy records. These patients came from 5 Canadian tertiary cancer centres. Patients who received abiraterone for approved indications were included. Demographics, prognostic factors, treatment outcomes and adverse events were abstracted.

Results: We included 187 patients who initiated abiraterone between January 2011 and June 2012. The median age at diagnosis and abiraterone start was 65 and 73 years, respectively. Seventy-three (39%) patients had metastatic disease at diagnosis. The Eastern Cooperative Oncology Group (ECOG) performance status of 0, 1, 2 and 3 was noted in 17, 96, 39 and 8 patients, respectively. The median prostate-specific antigen (PSA) at abiraterone start was 132, with a median PSA doubling time of 2.8 months. The median follow-up of patients still on active follow-up was 13 months. The proportion of patients achieving a ≥50% PSA reduction was 64/177 (36%). PSA progression-free survival was 3.5 months (95% confidence interval [CI], 3.0, 4.0). Median overall survival from start of abiraterone was 11 months (95% CI, 8.0, 13) and 38 months (95% CI, 31, 41) from date of mCRPC. Anemia and fatigue were the most commonly reported adverse events.

Conclusions: This study carries the inherent limitations of a retrospective chart review. The outcomes in this series of men treated with abiraterone in a non-trial setting were expected, considering previous clinical trials. Our results, therefore, support the generalizability of the COU-AA-301 study results.

Published
2014-09-09
How to Cite
Clayton, R., Wu, J., Heng, D., North, S., Emmenegger, U., Hotte, S., Chi, K., Zielinski, R., Al-Shamsi, H., Chen, L., & Eigl, B. (2014). A multicentre analysis of abiraterone acetate in Canadian patients with metastatic castration resistant prostate cancer. Canadian Urological Association Journal, 8(9-10), e583-90. https://doi.org/10.5489/cuaj.1891
Section
Original Research