ORLANDO, FL, USA (UroToday.com) - In this poster presentation, Dr. Chris Parker presented updated safety data from the ALSYMPCA trial. The ALSYMPCA trial was a phase III randomized, double-blind, placebo-controlled trial published in 2013 which demonstrated an overall survival benefit and increased time to a first skeletal-related event with the administration of radium-223 to men with metastatic CRPC with multiple symptomatic bony metastases.
At the time of initial publication and subsequent follow-up studies, radium-223 was found to have a favorable safety profile, owing to decreased depth of penetration of alpha particles, and thus decreased risk for myelosuppression. In this study presenting 3-year safety data, the authors reported that in both the radium-223 and placebo groups, over 90% of patients reported experiencing at least one treatment-related adverse event in the initial treatment period including the time up to 12 weeks from the last injection. A significantly lower proportion of patients receiving radium-223 (16%), however, experienced a grade 5 treatment-related adverse event during this time period compared to those receiving placebo 23% or those crossing over from placebo to treatment (21%). In the period from 12 weeks after the last injection to 3 years posttreatment, there was no difference between the groups with regards to treatment-related adverse events (5% vs. 3% vs. 8% for radium-223, placebo and crossover patients respectively). No difference was seen with regards to hematologic adverse events.
Serious adverse events experienced by radium-223 patients during this time period included aplastic anemia, anemia, constipation, diarrhea, multiorgan failure and pneumonia. In contrast, placebo-related adverse events included anemia and cardiopulmonary failure. At 3 years, 2 radium-223 patients and 3 placebo patients developed secondary malignancies (bladder and lymph node metastases not related to prostate cancer in radium-223; skin (2) and colon adenocarcinoma in placebo). No hematologic malignancies were reported. Six deaths were considered potentially attributable to radium-223 administration, of which 4 occurred in the 3 year posttreatment follow up period. The causes of these 4 deaths occurred once each and included, pulmonary embolism, pneumonia, multiorgan failure, and cerebrovascular accident.
The authors concluded that at 3 years, radium-223 remained safe and well-tolerated. Given its combined safety and efficacy, radium-223 remains a solid therapeutic option for mCRPC patients with bony metastases in the absence of visceral metastases.
Presented by Chris Parker, Nicholas J. Vogelzang, A. Oliver Sartor, Robert E. Coleman, Fang Fang, Irene Skjorestad, and Sten Nilsson at the 2015 Genitourinary Cancers Symposium - "Integrating Biology Into Patient-Centric Care" - February 26 - 28, 2015 - Rosen Shingle Creek - Orlando, Florida USA
The Royal Marsden NHS Foundation Trust and Institute of Cancer Research, Sutton, UK; Comprehensive Cancer Centers of Nevada, Las Vegas, NV, USA; Tulane Cancer Center, New Orleans, LA, USA; Weston Park Hospital, Sheffield, UK; Bayer HealthCare, Whippany, NJ, USA; Bayer AS (formerly Algeta ASA), Oslo, Norway; Karolinska University Hospital, Stockholm, Sweden
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Reported by Timothy Ito, MD, medical writer for UroToday.com