Researchers from Sweden and Norway have reported that bone-targeted radium-223 was associated with significant palliation in patients with hormone refractory prostate cancer (HRPC). The details of this randomized trial appeared in the July, 2007 issue of Lancet Oncology. 

Patients with HRPC have a number of treatment options but most are associated with significant toxicities. In addition to chemotherapy and radiotherapy there are 2 FDA approved bone targeted radioisotopes: Strontium-89 (Metastron®) and Samarium-153/lexidronam (Quadramet®). Thrombocytopenia and leucopenia are common side effects of these isotopes. radium-223 is an alfa emitter that may be less marrow toxic than Strontium-89 or Samarium-153. 

In this study, 64 patients with HRPC were randomly allocated to receive 4 infusions of radium-223 or placebo at 4 week intervals. These authors reported that bone alkaline phosphatase levels decreased by 66% in the group receiving radium-223 compared to a 9% increase in the control group. Time to first skeletal related event in the radium-223 group was 14 months compared to 11 months in the control group. Time to prostate antigen progression was 26 weeks in the radium-223 group compared to 8 weeks in the control group. Median overall survival was 65.3 weeks in the radium-223 group and 46.4 weeks in the control group. Importantly, hematologic toxicity was not different between the two groups. The only increased toxicity identified in the treatment arm was constipation. These authors concluded that radium-223 had a significant effect on bone alkaline phosphatase and improved survival compared to placebo with minimal side effects. 

Comments: These data are of interest because of the lack of apparent toxicity of radium-223. Comparable or better effects, may possibly be achieved with chemotherapy or other isotopes but these therapies are associated with significant toxicities. The next controlled trial should compare radium-223 to known effective treatment strategies for HRPC. 

Reference:  Nilsson S, Franzen L, Parker C, et al. Bone-targeted radium-223 in symptomatic, hormone-refractory prostate cancer: a randomized, multicentre, placebo-controlled phase II trial. Lancet Oncology. 2007; 8:587-594.

Related News: 

Y-J591 May Be Effective for Hormone-Refractory Prostate Cancer (9/9/2004) 

Satraplatin Effective for Treatment of Hormone Refractory Prostate Cancer (06/15/2007)

Docetaxel Improves Outcomes of Patients with Advanced Hormone Refractory Prostate Cancer (10/11/2004)

Avastin® Can Be Combined with Taxotere® and Emcyt® for the Treatment of Hormone Refractory Prostate Cancer (06/30/2003)

Randomized Trial Documents Higher Response Rate for Novantrone® But No Improvement in Survival For Men with Hormone Refractory Prostate Cancer (11/12/2002)

A Regimen of Paclitaxel, Estramustine and Paraplatin® is Very Effective for Hormone Refractory Prostate Cancer (11/11/2002)

Taxotere®-Estramustine Regimen May Be Best Current Regimen for Hormone Refractory Prostate Cancer (11/04/2002)

TAXOTERE®-BASED REGIMENS SHOWN TO BE MORE EFFECTIVE THAN CURRENT STANDARD THERAPY IN HORMONE REFRACTORY PROSTATE CANCER PATIENTS (05/31/2002)