`My husband has been on clinical trial with keytruda and xtandi for 5 months. Scans are stable but psa continues to rise now at 16.3!!! I don't think it is working, asked doctor about psma or axumin scan, said insurance doesn't pay (we are in NJ) Not sure of cost, he said it could show other mets as more sensitive and that doesn't mean they weren't there before, and doesn't mean the immunotherapy not working. I think we need to see where it is, chemo probably next step. He is not concerned with psa but it has doubled in less than 6 months which is terrible sign. I am very worried.