Cross resistance xtandi after Zytiga?

I must again ask you to please post his PC history in your signature - I have no idea how to comment without it. You are not providing enough information.

Keto is available as a systemic antifungal and would be prescribed off label.

Now I understand better, thanks.

Casodex, which is the same as bicalutamide, will not work, because the cancer has evolved to be resistant to it, and may even use it as fuel. (If that's the case, his PSA may have dropped briefly when Casodex was stopped.) Xtandi (enzalutamide) is an anti-androgen, much more potent than Bicalutamide, Nilutamide, Flutamide, or any of the previous generation. If Xtandi doesn't work, it is very doubtful that any of the others will.

-Allen