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Oncologist. 2021 Dec;26(12):1006-e2129. doi: 10.1002/onco.13949. Epub 2021 Sep 23.

Radium-223 plus Enzalutamide Versus Enzalutamide in Metastatic Castration-Refractory Prostate Cancer: Final Safety and Efficacy Results.

The oncologist

Benjamin L Maughan, Adam Kessel, Taylor Ryan McFarland, Nicolas Sayegh, Roberto Nussenzveig, Andrew W Hahn, John M Hoffman, Kathyrn Morton, Deepika Sirohi, Manish Kohli, Umang Swami, Kenneth Boucher, Benjamin Haaland, Neeraj Agarwal

Affiliations

  1. Genitourinary Oncology, Huntsman Cancer Institute, Salt Lake City, Utah, USA.
  2. The University of Texas MD Anderson Cancer Center, Houston, Texas, USA.
  3. Center for Quantitative Cancer Imaging, Huntsman Cancer Institute, Salt Lake City, Utah, USA.
  4. Department of Radiology and Imaging Sciences, Huntsman Cancer Institute, Salt Lake City, Utah, USA.
  5. ARUP Laboratories, University of Utah, Salt Lake City, Utah, USA.

PMID: 34423501 DOI: 10.1002/onco.13949

Abstract

LESSONS LEARNED: Long-term safety of radium-223 with enzalutamide was confirmed in this clinical trial. PSA-PFS2 was prolonged with the combination compared with enzalutamide alone.

BACKGROUND: Previously, we showed the combination of radium-223 and enzalutamide to be safe and associated with improved efficacy based on a concomitant decline in serum bone metabolism markers compared with enzalutamide alone in a phase II trial of men with metastatic castration-resistant prostate cancer (mCRPC) [1].

METHODS: Secondary endpoints were not included in our initial report, and we include them herein, after a median follow-up of 22 months. These objectives included long-term safety, prostate-specific antigen (PSA)-progression-free survival (PFS), and radiographic progression-free survival; PSA-PFS2 (time from start of protocol therapy to PSA progression on subsequent therapy); time to next therapy (TTNT); and overall survival (OS). Survival analysis and log-rank tests were performed using the R statistical package v.4.0.2 (https://www.r-project.org). Statistical significance was defined as p < .05.

RESULTS: Of 47 patients (median age, 68 years), 35 received the combination and 12 enzalutamide alone. After a median follow-up of 22 months, final safety results did not show any increase in fractures or other adverse events in the combination arm. PSA-PFS2 was significantly improved, and other efficacy parameters were numerically improved in the combination over the enzalutamide arm.

CONCLUSION: The combination of enzalutamide and radium-223 was found to be safe and associated with promising efficacy in men with mCRPC. These hypothesis-generating results portend well for the ongoing phase III PEACE III trial in this setting.

© AlphaMed Press; the data published online to support this summary are the property of the authors.

Keywords: Enzalutamide; Metastatic castration-refractory prostate cancer; Radium-223

References

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