ORLANDO, FL, USA (UroToday.com) - Radium-223 is an approved alpha-emitter shown to prolong survival in castrate-resistant prostate cancer (CRPC) with symptomatic bone metastasis. Here the group presents the results of their phase 1/2 study examining the safety and antitumor effects of Ra-223 + docetaxel vs docetaxel alone on bone alkaline phosphatase (bALP) and PSA.
Patients eligible for docetaxel with progressive CRPC and ≥ 2 bone metastasis were randomized 2:1 to Ra-223 + docetaxel vs docetaxel alone. bALP and PSA were recorded q3-6 weeks during treatment. Changes in both markers are described by the % of patients who achieved ≥ 30%, > 50%, and > 80% declines between baseline. Patients with elevated baseline bALP (≥ 21 µg/L) levels were included for the bALP analysis. bALP to below the upper limit of normal (ULN) was also recorded, regardless of % decline.
Forty-six patients (33 Ra-223 + docetaxel vs 13 docetaxel alone) were enrolled. Thirty-four patients had bALP above upper limit of normal. No patients in either group had an increase in bALP. Greater responses in bALP were seen in the Ra-223 + docetaxel group. For example, normalization of bALP was seen in 91% in Ra-223 + docetaxel group as opposed to 55% in the docetaxel only group. Additionally, greater decreases in PSA were also seen in the Ra-223 + docetaxel group. For example, 79% of patients in Ra-223 + docetaxel group experienced ≥ 30% decrease in PSA as compared to 62% in docetaxel only group.
They concluded that Ra-223 + docetaxel appears to favorably impact posttreatment PSA and bALP decline. Ra-223 + docetaxel also is particularly effective at normalizing bALP. The clinical benefits of changes in these serum markers still need to be determined.
Presented by Michael J. Morris, Celestia S. Higano, Howard I. Scher, Christopher Sweeney, Emmanuel S. Antonarakis, Daniel H. Shevrin, Charles J. Ryan, Yohann Loriot, Karim Fizazi, Neeta Pandit-Taskar, Jose E. Garcia-Vargas, Kari Lyseng, Marianne Bloma, Anne-Kirsti Aksnes, and Jorge A. Carrasquillo at the 2015 Genitourinary Cancers Symposium - "Integrating Biology Into Patient-Centric Care" - February 26 - 28, 2015 - Rosen Shingle Creek - Orlando, Florida USA
Memorial Sloan Kettering Cancer Center, New York, NY; Fred Hutchinson Cancer Research Center, Seattle, WA; Dana-Farber Cancer Institute, Boston, MA; The Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, Baltimore, MD; NorthShore University HealthSystem, Evanston, IL; UCSF Helen Diller Family Comprehensive Cancer Center, San Francisco, CA; Institut Gustave Roussy, University of Paris Sud, Villejuif, France; Bayer HealthCare, Whippany, NJ; Bayer AS, Oslo, Norway
Reported by Mohammed Haseebuddin, MD, medical writer for UroToday.com