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 ) .