We previously reported that abiraterone acetate and prednisolone (hereafter abiraterone) added at initiation of androgen deprivation therapy (ADT) improved survival of metastatic and very high-risk locally advanced prostate cancer and that combining with enzalutamide did not change efficacy.1 Using next-generation sequencing on plasma DNA, we previously showed that genomic alterations of the androgen receptor (AR) gene contribute to resistance to abiraterone or enzalutamide when initiated for metastatic castration-resistant prostate cancer after progression with ADT alone.2 It is unknown whether hormone intensification at start of ADT alters selection of AR alterations within the gene body and/or enhancer region.