On the Advanced Prostate Cancer Listserv there was a question raised about the need to use an antiandrogen (bicalutamide/Casodex, flutamide/Eulexin, or nilutamide/Nilandron) along with degarelix, the recently approved LHRH antagonist (a drug that halts the production of testicular androgens). Doctors who are knowledgeable about the use of LHRH antagonists (Zoladex, Lupron, Eligard, Viadur and Firmagon (degarelex) will always prescribe an antiandrogen (other than with degarelex) prior to the administration of the drug. When the LHRH antagonists are first administered the body initially works harder to produce androgens which will cause a PSA flare (PSA in this case is a surrogate marker for an increase of tumor load). The radical increase of tumor load can cause symptoms as bone pain, compression of a nerve root, spinal cord compression, or blockage of one or both urethras. This situation is often painful and always dangerous.

Degarelix works differently than the other LHRH antagonist as it does not cause a PSA flare and does not cause an increase in tumor load. So, the next question is, should degarelix be combined with an antiandrogen?

The merits of combining degarelix with a antiandrogen is not a clear cut issue (CAB or combined androgen blockade). CAB eliminates testicular androgens and it also blocks the androgen receptors. CAB comes with additional potential side effects and so it must be weighed as part of the decision making process.
Several randomized trials comparing LHRH antagonists alone (however not degarelex) vs CAB have demonstrated a survival benefit with CAB. However, in one of the largest trials conducted by the United St