NEW ORLEANS, LA USA (UroToday.com) - During today’s moderated poster session on advanced prostate cancer, Dr. Neal Shore and associates presented their work on an expanded access program (EAP) to monitor the safety of radium-223. Ra-223 is the first approved alpha-emitting radiopharmaceutical with cytotoxic effect on bone metastases (mets). The phase 3 ALSYMPCA study showed OS improvement of 3.6 months compared to placebo and standard of care.
The EAP was a phase 2 prospective, open-label, multicenter study designed to provide early access of Ra-223 in patients with CRPC and symptomatic bone mets. A cohort of 184 men with 2+ radiographically proven mets and no lung/liver/brain mets were treated with 6 cycles of Ra-223 and assessed for performance score, skeletal events, and emergent adverse events. Secondary outcomes included analysis of overall survival, along with safety and survival stratified by treatment with abiraterone or enzalutamide. The treatment period was completed 30 days after the last dose.
Median age in the cohort was 70-years old. 165/184 (90%) had ECOG 0 or 1. Median PSA of the overall group was 129. Seventeen (9%) patients were on bisphosphonates, 31 (17%) had current use of denosumab, 110 (60%) had received prior docetaxel. Eighty-one patients received all 6 injections of Ra-223. The cohort included 120 (65%) patients previously on abiraterone and 25 (14%) patients concurrently on abiraterone. Fifty-nine (32%) previously used and 15 (8%) concurrently used enzalutamide. There were no deaths associated with Ra-223, and 8 deaths overall during the study period. Median OS was 17 months in the EAP population, which was similar among those with prior use of abiraterone and/or enzalutamide. Median OS for those with concurrent abiraterone was not estimable, and for those without concurrent abiraterone, it was 15.6 months. Median OS for those with and without concurrent enzalutamide was 10.7 and 17.1 months, respectively. Overall rate of Grade 3-4 events was 36%. The most common adverse events included anemia, thrombocytopenia, and back pain, and rates of adverse events were identical across all subgroups.
The authors concluded that Ra-223 was well tolerated among patients on abiraterone or enzalutamide. OS was comparable in Ra-223-treated patients who received prior abiraterone and/or enzalutamide vs the overall EAP population. This expanded access program study, along with further trials of Ra-223 combinations, adds important information to the growing body of literature on multi-agent therapy for advanced prostate cancer.
Presented by Neal D. Shore, MD at the American Urological Association (AUA) Annual Meeting - May 15 - 19, 2015 - New Orleans, LA USA
Carolina Urologic Research Center, Myrtle Beach, SC USA
Reported by Nikhil Waingankar, medical writer for UroToday.com