- In men with high-risk metastatic castration-resistant prostate cancer (mCRPC), detection of androgen receptor splice variant 7 (AR-V7) in circulating tumor cells (CTC) was independently associated with worse survival with abiraterone or enzalutamide.
Why this matters
- AR-V7-positive patients should be offered alternative treatments.
- Multicenter, prospective-blinded PROPHECY study of 118 men with high-risk mCRPC who received abiraterone acetate or enzalutamide.
- AR-V7 detection was done by 2 blood-based Johns Hopkins University (JHU)-modified and EPIC sciences assays.
- Funding: Prostate Cancer Foundation; Movember.
- Median follow-up time, 19.6 months.
- The percentage agreement between the 2 assays was 82%.
- Presence of AR-V7 by Johns Hopkins and Epic AR-V7 assays was independently associated with shorter:
- PFS (HR, 1.9 [P=.032] and HR, 2.4 [P=.020], respectively).
- OS (HR, 4.2 [95% CI, 2.1-8.5] and HR, 3.5 [95% CI, 1.6-8.1], respectively).
- No Epic AR-V7-positive patients had a confirmed PSA or RECIST response.
- 11% and 6% of JHU AR-V7-positive patients had confirmed PSA and RECIST responses, respectively.
- Lack of testing with alternative treatment strategies.