Aim: Abiraterone acetate has been approved by the PBS in Australia since mid 2013 as a treatment for men with castrate-refractory prostate cancer post-taxane based chemotherapy. This approval was based on the promising results from the COU AA 301 study which demonstrated a statistically significant 4.6 month improvement in median overall survival. This audit was conducted to look at the efficacy and tolerability of abiraterone acetate in the post chemotherapy setting in a regional cancer centre.
Methods:
A retrospective chart audit was done in Gold Coast University Hospital of patients who have been treated with Abiraterone from August 2013 till July 2014 A total of 22 patients were audited. Variables assessed included age, ECOG, disease burden, tissue diagnosis, and treatment prior to abiraterone. Outcomes assessed included side effects, PSA halving time, progression-free survival and treatment beyond progression.
Findings:
Twelve patients progressed on the treatment, with the duration of treatment ranging from two to ten cycles. Five patients subsequently discontinued therapy, and three were rechallenged with chemotherapy. Seven patients had stable disease, with the treatment duration ranging from one to eleven cycles of Abiraterone. The majority of the patients had one course of docetaxel prior to abiraterone, two patients having been rechallenged with docetaxel and cabazitaxel prior to starting abiraterone. Cycles of prior chemotherapy ranged from one to fourteen, with only two patients receiving more than ten cycles. Bone disease was predominant, followed by lymph node and visceral metastases.
Eight patient ceased the medication, four of them due to progression and four due to side effects. Fluid retention was the most common side effect, followed by fatigue,and dermatological toxicities. The median progression-free survival was 6 months, with overall survival being presented later.
Conclusion:
Abiraterone was generally well tolerated, with only four patients ceasing the medication secondary to side effects. The median progression free survival was six months which was comparable to the original study.