We have a number of newer hormone pathway drugs now available to treat men with metastatic castrate resistant prostate cancer (mCRPC). Researchers have shown that prostate specific antigen (PSA) response can be used as a pharmaco-dynamic end-point that may help identify men with early resistance to these new drugs. They found that there is clinical significance of an early PSA response (EPR) during therapy with enzalutamide, abiraterone acetate (AA) and orteronel in mCRPC.

The researchers evaluated PSA values at baseline and then 28 days after beginning treatment in men who were recruited from other clinical trials. They defined EPR as a decline >50% from baseline. The effects of clinical characteristics on radiographic progression-free survival (rPFS) and overall survival (OS) were also examined.

They determined that EPR is an independent prognostic factor in men with mCRPC treated with next-generation androgen pathway drugs and may be useful for the therapeutic decisions. So, if you are starting any of these drugs question your doctor if you should change your treatment if by the end of the first month of starting your PSA has not declined by at least 50%.

European journal of cancer (Oxford, England : 1990). 2016 May 02 [Epub ahead of print];Fuerea, Baciarello, Patrikidou; etal.

http://www.ncbi.nlm.nih.gov/pubmed/27151554