Clonal Emergence and Regression During Radium-223 Therapy for Metastatic Prostate Cancer

This study proposes to document the presence of clonal emergence and regression during radium-223 therapy for metastatic prostate cancer by serial ctDNA analysis of tumor-associated mutations, using the clinically-available Guardant 360 platform. These data may provide important mechanistic insights into radium-223 therapy by 1) identifying mutations associated with radium-223 resistance or sensitivity, 2) providing new markers of treatment response in an individual, and 3) revealing antitumor effects from radium-223 that are not easily recognized with standard tumor response metrics. Positive finding based on this clinically-available platform will be readily applied by the oncology treatment community.