The authors retrospectively reviewed the Flatiron electronic health record database to identify patients with mCRPC who progressed on 1L NAH and started 2L monotherapy with Ra-223 (n=120) or NAH (n=226) between January 2013 and December 2018. The authors then descriptively characterized patient characteristics, overall survival (OS) from the start of second-line therapy, and symptomatic skeletal events (SSEs).
Patients who received a second NAH and those who switched to Ra-223 had generally similar characteristics at the time of initiating second-line therapy, including similar rates of bone-health agents. However, patients who initiated Ra-223 in the second-line setting had a higher incidence of bone-only metastases, a shorter duration of first-line NAH, and a higher rate of prior SSEs than the second-line NAH cohort.
From the start of second-line therapy, the median duration of second-line therapy was 5.6 months (median 4.5 doses) for patients receiving Ra-223 and 4.7 months for patients receiving second-line NAH. Median overall survival from the start of second-line therapy was 10.8 months for patients receiving Ra-223 and 11.2 months for patients receiving second-line NAH, with 49% and 39%, respectively, receiving subsequent therapy.
Among those who received subsequent therapy after the second-line setting, the use of subsequent taxanes was lower in the Ra-223 cohort (47%) than in the second-line NAH cohort (76%).
After the start of second-line therapy, SSEs were observed starting in 32 patients (27%) on Ra-223 and 49 (22%) on second-line NAH.
On the basis of these data, the authors conclude that overall survival is similar in these two subgroups of patients with mCRPC (hazard ratio 1.26, 95% confidence interval 0.92 to 1.74).
Presented by: Oliver A. Sartor, MD, Professor of Medicine; Medical Director, Tulane Cancer Center; C. E. and Bernadine Laborde Professor of Cancer Research in New Orleans, LA
Co-Authors: Daniel J. George, Bertrand Tombal, Celestia S. Higano, Cora N. Sternberg, Kurt Miller, Xiaolong Jiao, Helen Guo, Per Sandstrom, Frank Verholen, Fred Saad, Neal D. Shore
Written by: Christopher J.D. Wallis, Urologic Oncology Fellow, Vanderbilt University Medical Center Twitter @WallisCJD during the 2021 ASCO Genitourinary Cancers Symposium (ASCO GU), February 11th to 13th, 2021