Dr. Hwang on the Addition of Radium-223 to Abiraterone Acetate and Prednisone in mCRPC

Clara Hwang, MD, a medical oncologist with Henry Ford Health System, discusses the phase 3 ERA-223 trial evaluating the addition of radium-223 dichloride (Xofigo) to abiraterone acetate (Zytiga) and prednisone in patients with metastatic castration-resistant prostate cancer (mCRPC) and bone metastases.

In the trial, investigators examined the addition of radium-223, a bone-targeting agent and alpha emitter, in this patient population, says Hwang. Investigators know that when radium-223 is used in bone-predominant disease, it can improve survival based on the data from the ALSYMPCA trial. The primary end point of the ERA-223 trial was symptomatic skeletal event-free survival. Data from the primary analysis revealed that 49% of patients in the radium-223 group experienced at least 1 symptomatic skeletal event or died, compared with 47% in the placebo group. The median symptomatic skeletal event-free survival was 22.3 months in the radium-223 group versus 26.0 months in the placebo group.

Unfortunately, the trial was negative and there was a signal that these skeletal events would be increased with the addition of radium-223, Hwang adds. This trial shows that there may be some bone toxicities with both of these agents, and when added together, patients need to be carefully monitored, concludes Hwang.