As a follow-up, the REASSURE trial is a single-arm, prospective long-term observational study designed to evaluate long-term safety at 7 years’ follow up. In the study, patients with mCRPC with bone metastases were enrolled and planned to receive Ra-223. In this abstract, the authors provide the first interim analysis of 244 men treated in the United States – they have enrolled over 1106 men globally (421 United States), but only 244 were eligible for analysis. The primary aim was a descriptive analysis of safety and characteristics according to (1) prior or (2) concomitant abiraterone/enzalutamide (abi/enza) or (3) prior docetaxel/cabazitaxel (chemo) treatment in men who had received ≥1 Ra-223 dose; median follow up 8 months. Most men were ECOG 0-1.
20% had received prior chemotherapy (docetaxel/cabazitaxel), 19% had received prior abiraterone and/or enzalutamide, and 34% were treated concomitantly with abi or enza. 48% of men who had received prior abi/enza had also received prior chemotherapy; 44% of men who had received prior chemotherapy had also received prior abi/enza.
The median number of Ra-223 doses received was 6. Close to 70% completed 5-6 injections.
The key findings were that:
1. Prior abi/enza and/or chemo men had higher median baseline PSA and were less likely to complete 5-6 doses.
2. Subgroups had similar median ALP, LDH and Hb
3. Drug-related tx-emergent adverse events occurred in 71 pts (29%) and serious AEs in 9 (3.7%). Most common AEs were diarrhea (9%), fatigue (8%) and anemia (7%). Drug-related serious AE’s occurred in 4% of patients.
4. AE incidence was numerically higher in pts who received prior chemo and/or prior abi/enza
5. In the updated safety analysis, 51/244 (21%) had a symptomatic skeletal related event (SSE)
Based on this interim analysis, there are no new safety concerns and most men complete 5-6 Ra-223 doses in routine US clinical practice. Men who received prior abi/enza or prior chemo had lower Ra-223 treatment completion and higher AE incidence – this is likely due to greater disease burden, as they had a higher median baseline PSA.
Speaker: Lauren Christine Harshman
Co-Authors: AA. Oliver Sartor, Timothy Richardson, John Sylvester, Daniel Y. Song, Constantine Mantz, Robert K. Brookland, Mark Perlmutter, Robert Given, Jan Kalinovsky, Svetlana Babajanyan, Yoriko De Sanctis, Celestia S. Higano
Institution(s): Dana-Farber Cancer Institute, Boston, MA; Tulane University School of Medicine, New Orleans, LA; Wichita Urology, Wichita, KS; 21st Century Oncology, Lakewood Ranch, FL; Johns Hopkins School of Medicine, Baltimore, MD; 21st Century Oncology, Fort Myers, FL; Chesapeake Urology, Towson, MD; Jersey Shore Medical Center, Neptune, NJ; Urology of Virginia, Virginia Beach, VA; Bayer HealthCare Pharmaceuticals Inc., Basel, Switzerland; Bayer HealthCare Pharmaceuticals Inc., Whippany, NJ; University of Washington and Fred Hutchinson Cancer Research Center, Seattle, WA
Written by: Thenappan Chandrasekar, MD, Clinical Fellow, University of Toronto, Twitter: @tchandra_uromd at the 2018 American Society of Clinical Oncology Genitourinary (ASCO GU) Cancers Symposium, February 8-10, 2018 - San Francisco, CA
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