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.

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.

• Authors: Mariana Reza, Robert Jones, John Aspegren, Christophe Massard, Leena Mattila, Mika Mustonen, Per Wollmer, Elin Trägårdh, Eva Bondesson, Lars Edenbrandt, Karim Fizazi, Anders Bjartell
• Journal: European urology focus (Eur Urol Focus) Vol. 2 Issue 5 Pg. 547-552 (Dec 2016) ISSN: 2405-4569 [Electronic] Netherlands
• PMID: 28723521 (Publication Type: Journal Article)
• Copyright: Copyright © 2016 European Association of Urology. Published by Elsevier B.V. All rights reserved.