In a nutshell
This study examined whether the duration of primary (first round) hormone therapy impacts abiraterone (Zytiga) treatment for metastatic castration-resistant prostate cancer (mCRPC). Researchers concluded that the benefits of abiraterone were not dependent on the duration of primary hormone therapy.
Some background
Androgen deprivation therapy (ADT) is a type of hormone therapy for prostate cancer. It is often the first-line treatment for metastatic prostate cancer (cancer that has spread to distant parts of the body). Reducing the level of male sex hormones and their effect on cancer cell growth can dramatically improve survival. Over time, however, cancer can continue to spread despite standard hormone therapy. This is known as metastatic castration-resistant prostate cancer (mCRPC).
Abiraterone is often recommended as a secondary hormone therapy in men with mCRPC. Many studies have demonstrated improved survival with abiraterone treatment for mCRPC. Whether the duration of primary ADT can limit the effectiveness of abiraterone is still being investigated.
Methods & findings
This study aimed to examine the effect of previous ADT treatment time on abiraterone treatment for mCRPC.
The results of 2 separate trials involving a total of 4,277 men with mCRPC were included in analysis. Men were randomly assigned to receive either abiraterone treatment or placebo (control drug with no active effect). The average duration of previous ADT drug therapy was 36.7 to 45.1 months. 4 to 7% of men underwent surgical ADT (removal of testicles).
Overall, abiraterone significantly improved treatment outcomes compared to placebo. These included overall survival (time from treatment until death from any cause), disease progression (based on imaging tests), and treatment response (based on blood tests).
Previous ADT duration showed no significant effect on abiraterone treatment in terms of overall survival and disease progression. In fact, patients who received longer ADT showed a greater benefit with abiraterone. This was most pronounced among men who had not previously undergone chemotherapy.
Abiraterone improved overall survival by 22 to 32% among men with 61 months or more of ADT. In contrast, 28 months or less of previous ADT was associated with a benefit on overall survival of 1 to 21%. The time to disease progression was also more favorable with longer previous ADT.
The bottom line
Researchers concluded that abiraterone treatment improves survival and disease progression in men with mCRPC regardless of previous ADT duration.
Published By :
European Urology
Date :
Oct 24, 2015
