Dr. Armstrong on the Rationale of the PROPHECY Trial in mCRPC

Andrew J. Armstrong, MD, professor of medicine, associate professor in pharmacology and cancer biology, and professor in surgery at Duke University School of Medicine and a member of the Duke Cancer Institute, discusses the rationale of the PROPHECY trial in metastatic castration-resistant prostate cancer (mCRPC).

The purpose of the PROPHECY study was to develop a molecular taxonomy of prostate cancer using liquid biopsies with a primary objective of validating AR-V7 as a predictive biomarker for treating men with metastatic CRPC with abiraterone acetate (Zytiga) or enzalutamide (Xtandi), explains Armstrong. This study was granted the Prostate Cancer Foundation Global Challenge Award and required 5 centers, as well as 5 central labs, to conduct the research.

The results were published in 2019 in the Journal of Clinical Oncology, which established AR-V7 as a negative predictive biomarker for response to abiraterone or enzalutamide. The biopsies were conducted using the Johns Hopkins University modified-AdnaTest CTC AR-V7 mRNA assay and the Epic Sciences CTC nuclear-specific AR-V7 protein assay. Both assays were associated with low possibility of prostate-specific antigen response, and objective response as well as short progression-free survival and overall survival in a multivaried analysis, concludes Armstrong.