Dr. Luke Nordquist on Radium-223 Retreatment

Luke Nordquist, MD, FACP, a urologic medical oncologist and CEO of the Urology Cancer Center and GU Research Network, discusses a multicenter, prospective study of radium-223 retreatment in metastatic castration-resistant prostate cancer (mCRPC).

There were many questions that remained unanswered after the ALSYMPCA study, which led to the approval of radium-223, said Nordquist. One area where uncertainty remains is proper dosing. While this drug is approved at 50 kBq/kg monthly for 6 months in mCRPC, a higher dose may have more benefit.

To investigate this, a study was conduced with 44 patients who had mCRPC. The patients received up to an additional 6 doses of radium-223 after the original 6. The primary endpoint of the study was safety, but there were exploratory endpoints with radiographic progression and progression-free survival looking at PSA. In terms of safety, there was no marked differences compared with the safety of the ALSYMPCA trial. There was not a difference in the hematologic toxicity with the additional 6 doses, and there were no grade 4/5 hematologic toxicities reported, said Nordquist.