AR-V7 status predicts abiraterone, enzalutamide response in mCRPC
medwireNews: Men positive for androgen receptor splice variant 7 (AR-V7) in circulating tumor cells (CTCs) derive little benefit from abiraterone or enzalutamide in the treatment of metastatic castration-resistant prostate cancer (mCRPC), US researchers report.
Andrew Armstrong (Duke University, Durham, North Carolina) and colleagues write in the Journal of Clinical Oncology that “such men with mCRPC should be offered alternative treatments.”
The prospective, blinded PROHPECY study included 118 men with progressive, high-risk mCRPC who were starting treatment with abiraterone acetate (n=55), enzalutamide (n=58), or both (n=5) at five academic medical centers in the USA.
Of these, 24% were AR-V7 positive using the Johns Hopkins University (JHU) modified-AdnaTest CTC AR-V7 messenger (m)RNA assay and 9% were AR-V7 positive according to the Epic Sciences CTC nuclear-specific AR-V7 protein assay (Epic, San Diego, California). The percentage agreement between the two assays was 82%, with 17 of the 19 discordant results being JHU AR-V7 positive but Epic AR-V7 negative.