Background: Prior studies suggest that elevated markers of bone turnover are prognostic for poor survival in castration-resistant prostate cancer (CRPC). The predictive role of these markers relative to bone-targeted therapy is unknown. We prospectively evaluated the prognostic and predictive value of bone biomarkers in sera from CRPC patients treated on a placebo-controlled phase III trial of docetaxel with or without the bone targeted endothelin-A receptor antagonist atrasentan (SWOG S0421).
Methods: Markers for bone resorption (N-telopeptide and pyridinoline) and formation (C-terminal collagen propeptide and bone alkaline phosphatase) were assayed in pretreatment and serial sera. Cox proportional hazards regression models were fit for overall survival. Models were fit with main effects for marker levels and with/without terms for marker-treatment interaction, adjusted for clinical variables, to assess the prognostic and predictive value of atrasentan. Analysis was adjusted for multiple comparisons. Two-sided P values were calculated using the Wald test.
Results: Sera from 778 patients were analyzed. Elevated baseline levels of each of the markers were associated with worse survival (P < .001). Increasing marker levels by week nine of therapy were also associated with subsequent poor survival (P < .001). Patients with the highest marker levels (upper 25th percentile for all markers) not only had a poor prognosis (hazard ratio [HR] = 4.3; 95% confidence interval [CI] = 2.41 to 7.65; P < .001) but also had a survival benefit from atrasentan (HR = 0.33; 95% CI = 0.15 to 0.71; median survival = 13 [atrasentan] vs 5 months [placebo]; P interaction = .005).
Conclusions: Serum bone metabolism markers have statistically significant independent prognostic value in CRPC. Importantly, a small group of patients (6%) with highly elevated markers of bone turnover appear to preferentially benefit from atrasentan therapy.
Written by:
Lara PN Jr1, Ely B, Quinn DI, Mack PC, Tangen C, Gertz E, Twardowski PW, Goldkorn A, Hussain M, Vogelzang NJ, Thompson IM, Van Loan MD Are you the author?
University of California Davis Comprehensive Cancer Center, Sacramento, CA (PNL, PCM); Southwest Oncology Group Statistical Center, Seattle, WA (BE, CT); University of Southern California Norris Cancer Center, Los Angeles, CA (DIQ, AG); USDA Western Human Nutrition Center at University of California Davis, Davis, CA (EG, MVL); City of Hope, Duarte, CA (PT); University of Michigan, Ann Arbor, MI (MH), US Oncology, Las Vegas, NV (NJV); Cancer Treatment and Research Center, University of Texas, San Antonio, TX (IT)
Reference: J Natl Cancer Inst. 2014 Mar 10. (Epub ahead of print)
doi: 10.1093/jnci/dju013
PubMed Abstract
PMID: 24565955
