Wednesday 19 December 2012

Zytiga to be Trialled as First Line Therapy

A three arm clinical trial has started looking at comparing Zytiga plus Prednisone alone, versus Zytiga plus Prednisone in combination with Degarelix, versus Degarelix alone for men who have received surgical prostate removal but the PSA has started to rise.

This will be the first time the Zytiga Prednisone Combo (ZPC) alone has been tested as the first line therapeutic option once surgery has failed.

Degarelix is a new LHRH antagonist given as a monthly injection and has similar activity in lowering testosterone levels to the LHRH agonists Lupron and Zoladex. Zytiga is taken as 4 x 250 mg tablets daily together with 5 mg of Prednisone daily. This is not a blinded trial since the patients will know if they are taking daily tablets or receiving a monthly injection.

Degarelix does not stop androgen production altogether and low levels of testosterone can be detected in the plasma of patients taking Degarelix. In contrast Zytiga inhibits CYP17 to bring about total androgen ablation as a single agent so Zytiga alone should work better than Degarelix alone and the combination of Degarelix with Zytiga will possibly be no better than Zytiga alone making since mechanistically speaking Zytiga makes Degarelix redundant.

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