Concurrent or layered treatment with radium-223 and enzalutamide or abiraterone/prednisone: real-world clinical outcomes in patients with metastatic castration-resistant prostate cancer.

In this study, we evaluated real-world data on radium-223 plus abiraterone/prednisone or enzalutamide. Previously, the ERA 223 trial (NCT02043678) demonstrated increased fracture risk with concurrent treatment with radium-223 and abiraterone plus prednisone/prednisolone in patients with metastatic castration-resistant prostate cancer (mCRPC).

We used the Flatiron Health database to perform a retrospective study of patients with mCRPC treated with radium-223. Treatment with radium-223 plus abiraterone/prednisone or enzalutamide was defined as concurrent if both drugs started within 30 days of one another, or layered when the second drug started ≥30 days after the first. The index date was defined as the day of the first radium-223 dose. Outcome measures included symptomatic skeletal events (SSEs), overall survival (OS), and patterns of treatments received.

Of the 625 patients treated with radium-223, 22% received it together with abiraterone/prednisone and 27% with enzalutamide. When these agents were combined, they were often initiated in a layered fashion (73% layered, 23% concurrent). Prior or concomitant bone health agents (BHAs) were received by 67% and 55% of patients, respectively. Median follow-up was 9 months. Overall, incidence rates for SSEs and pathologic fractures were 0.35 and 0.11 patients per person-year, respectively. Median OS from mCRPC diagnosis was 28.1 months.

In this real-world setting, combination treatments with radium-223 and abiraterone/prednisone or enzalutamide were common. These agents were more commonly given in a layered than a concurrent fashion. Incidence rates for SSEs were reduced when BHAs were used; however, BHAs were underutilized.

Prostate cancer and prostatic diseases. 2020 May 13 [Epub ahead of print]

Neal Shore, Celestia S Higano, Daniel J George, Cora N Sternberg, Fred Saad, Bertrand Tombal, Kurt Miller, Jan Kalinovsky, XiaoLong Jiao, Krishna Tangirala, Oliver Sartor

Carolina Urologic Research Center, Myrtle Beach, SC, USA. ., Department of Medicine, University of Washington and Fred Hutchinson Cancer Research Center, Seattle, WA, USA., Departments of Medicine and Surgery, Duke Cancer Institute, Duke University, Durham, NC, USA., Weill Cornell Department of Medicine, New York-Presbyterian Hospital, New York, NY, USA., University of Montreal Hospital Center, Montreal, QC, Canada., Division of Urology, IREC, Cliniques Universitaires Saint Luc, UCLouvain, Brussels, Belgium., Charité Universitätsmedizin Berlin, Urologische Klinik und Hochschulambulanz, Berlin, Germany., Bayer Consumer Care AG, Basel, Switzerland., Bayer HealthCare Pharmaceuticals, Whippany, NJ, USA., Tulane Cancer Center, Tulane University School of Medicine, New Orleans, LA, USA.