THE LONDON PROSTATE CANCER CENTRE NEWSLETTER | SPRING 2013 Abiraterone -A New Addition to the Armamentarium in Prostate Cancer Treatment D Scott Ernst MD FRCPC Launched in 2008, a large clinical trial (COU-AA-301) was conducted which compared Abiraterone to placebo in over 1000 men who had castrate resistant disease and who had failed primary chemotherapy. First reported in 2011, the study showed that the overall survival amongst those men who received the Abiraterone was increased by over 4 months and that the risk of dying from prostate cancer was reduced by 25%. No other previous treatments for patients who progressed after chemotherapy had proven to be as beneficial as Abiraterone. Abiraterone is taken in capsule form once a day. Side effects are generally quite mild and include fatigue, joint and muscle discomfort, swelling and diarrhea. Because Abiraterone interferes with the body’s natural cortisol production, a supplement (Prednisone) is required to be given along with the Abiraterone. The Prednisone may itself lead to side effects, such as low blood potassium, high blood pressure Cancer cells. and fluid retention. Although these agents are generally well tolerated, side effects should be reported and monitored. In some instances, the physician may need to make some changes or prescribe additional or alternate treatments. In January 2013, the New England Journal of Medicine reported on another trial (COU-AA-302) comparing Abiraterone to placebo in 1000+ men before they received chemotherapy. Once again, the use of Abiraterone appeared to be effective in delaying the need for standard chemotherapy and may improve survival outcomes if started earlier in the development of castrate resistance. The final results of this study have not yet been reported because patients still remain in the program and more follow-up time is required. continued on page 3 I t has been long established that prostate cancer cells require the presence of male hormones (androgens) such as testosterone , in order to grow and multiply. For the past 60 years, the cornerstone of treatment of advanced prostate cancer has been the use of anti-androgens, which work by suppressing the production of testosterone or by blocking its action with the androgen receptors on the tumor cells. It has also been found that, over time, the prostate cancer cells develop a renewed sensitivity to the presence of androgens and start to grow again -even when androgen levels are kept low. This phenomenon is termed “castrate resistance”. Chemotherapy is commonly used when castrate resistance develops. However, within 6-24 months, the prostate cancer cells will also become resistant to the chemotherapy and the prostate cancer will progress once again.