Not FDA-approved yet. The FDA has recently accepted rPFS as a surrogate endpoint for overall survival. It remains to be seen if they will accept it for this indication. No data yet:
Xtandi beneficial in reducing radiogr... - Advanced Prostate...
Yes, that's why. It's not at all clear that delaying the detection of new metastases prolongs survival. The FDA has just issued new guidance on surrogate endpoints:
They suggest that drug companies consult with them before designing clinical trials. They approved Erleada and Xtandi for non-metastatic CRPC based on rPFS, but that's a different situation.