Bone Scan Index and Progression-free Survival Data for Progressive Metastatic Castration-resistant Prostate Cancer Patients Who Received ODM-201 in the ARADES Multicentre Study

Mariana Reza, Robert Jones, John Aspegren, Christophe Massard, Leena Mattila, Mika Mustonen, Per Wollmer, Elin Trägårdh, Eva Bondesson, Lars Edenbrandt, Karim Fizazi, Anders Bjartell

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    Abstract

    Background ODM-201, a new-generation androgen receptor inhibitor, has shown clinical efficacy in prostate cancer (PCa). Quantitative methods are needed to accurately assess changes in bone as a measurement of treatment response. The Bone Scan Index (BSI) reflects the percentage of skeletal mass a given tumour affects. Objective To evaluate the predictive value of the BSI in metastatic castration-resistant PCa (mCRPC) patients undergoing treatment with ODM-201. Design, setting, and participants From a total of 134 mCRPC patients who participated in the Activity and Safety of ODM-201 in Patients with Progressive Metastatic Castration-resistant Prostate Cancer clinical trial and received ODM-201, we retrospectively selected all those patients who had bone scan image data of sufficient quality to allow for both baseline and 12-wk follow-up BSI-assessments (n = 47). We used the automated EXINI bone BSI software (EXINI Diagnostics AB, Lund, Sweden) to obtain BSI data. Outcome measurements and statistical analysis We used the Cox proportional hazards model and Kaplan-Meier estimates to investigate the association among BSI, traditional clinical parameters, disease progression, and radiographic progression-free survival (rPFS). Results and limitations In the BSI assessments, at follow-up, patients who had a decrease or at most a 20% increase from BSI baseline had a significantly longer time to progression in bone (median not reached vs 23 wk, hazard ratio [HR]: 0.20; 95% confidence interval [CI], 0.07–0.58; p = 0.003) and rPFS (median: 50 wk vs 14 wk; HR: 0.35; 95% CI, 0.17–0.74; p = 0.006) than those who had a BSI increase >20% during treatment. Conclusions The on-treatment change in BSI was significantly associated with rPFS in mCRPC patients, and an increase >20% in BSI predicted reduced rPFS. BSI for quantification of bone metastases may be a valuable complementary method for evaluation of treatment response in mCRPC patients. Patient summary An increase in Bone Scan Index (BSI) was associated with shorter time to disease progression in patients treated with ODM-201. BSI may be a valuable method of complementing treatment response evaluation in patients with advanced prostate cancer.

    Original languageEnglish
    Pages (from-to)547-552
    Number of pages6
    JournalEuropean Urology Focus
    Volume2
    Issue number5
    DOIs
    Publication statusPublished - 1 Dec 2016

    Keywords

    • Androgen receptor antagonists
    • Bone metastasis
    • Bone scan index
    • Metastatic castration-resistant prostate cancer
    • ODM-201
    • Radiographic progression-free survival

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