#GU15 - Prior and concurrent use of abiraterone and enzalutamide with Ra-223 in an expanded access setting - Session Highlights

ORLANDO, FL, USA (UroToday.com) - The aim of the prospective early-access program (EAP) was to monitor acute and long-term safety of Ra-223. The ALSYMPCA RA-223 Phase III trial that led to FDA approval of Ra-223 was completed prior to approval of abiraterone (AA) and Enzalutamide (ENZ). EAP provides a valuable resource to report on experience with RA-223 in relationship to AA and ENZ

gucancerssympaltSymptomatic bone metastatic CRPC patients in the United States who were ineligible for, or had prior docetaxel, were enrolled in the study. Treatment included Ra-223 concurrent with standard of care medications, which can include AA and ENZ. Analyses were conducted to assess safety and overall survival (OS) in patients with prior and concurrent AA and ENZ.

Of 184 treated, 120 (65%) had prior and 35 (19%) patients had concurrent AA. Fifty-nine (32%) had prior and 25 (14%) patients had concurrent ENZ. Patients with no concurrent AA or ENZ had a similar OS to the overall group (AA 16 mo, ENZ 17 mo, overall 17 mo). Patients who received concurrent first-line therapy (AA or ENZ) with no prior AA or ENZ appear to have a longer OS. However, median OS was not calculated due to small number of events. Eight deaths occurred during treatment and none were related to RA-223.

The rate of Grade 3-5 AEs was similar across concurrent (AA 37%, ENZ 36%) and prior groups (AA 43%, ENZ 42%) vs overall 41%. Most frequently occurring Gr 3-4 events were anemia (AA 17%, ENZ 8%, overall 11%), thrombocytopenia (AA 6%, overall 3%), and back pain (ENZ 8%, overall 4%).

In conclusion, this study provides important information of the utility of Ra-223 along with abiraterone or enzalutamide. Ra-223 was well tolerated when added to AA or ENZ or concurrently administered with Ra-223. Preliminary findings of OS in patients receiving first-line AA or ENZ concurrently with Ra-223 is provocative, needs further follow-up, and needs further investigation.

Presented by A. Oliver Sartor, Daniel Celestino Fernandez, Michael J. Morris, Andrei Iagaru, Alan Brown, Fabio Almeida, Christopher Sweeney, Matthew Raymond Smith, Adam Dicker, Yu-Ning Wong, Neal D. Shore, Jeremy Gratt, Oana Petrenciuc, and Nicholas J. Vogelzang at the 2015 Genitourinary Cancers Symposium - "Integrating Biology Into Patient-Centric Care" - February 26 - 28, 2015 - Rosen Shingle Creek - Orlando, Florida USA

Tulane Cancer Center, New Orleans, LA; Moffitt Cancer Center, Tampa, FL; Memorial Sloan Kettering Cancer Center, New York, NY; Stanford University, Stanford, CA; 21st Century Oncology, Fort Myers, FL; Arizona Molecular Imaging Center, Phoenix, AZ; Dana-Farber Cancer Institute, Boston, MA; Massachusetts General Hospital, Boston, MA; Thomas Jefferson University, Philadelphia, PA; Fox Chase Cancer Center, Temple University Health System, Philadelphia, PA; Carolina Urologic Research Center, Myrtle Beach, SC; Bayer HealthCare, Whippany, NJ; Comprehensive Cancer Centers of Nevada, Las Vegas, NV

Reported by Mohammed Haseebuddin, MD, medical writer for UroToday.com