Exploratory analyses showed that low VEGF-A levels were associated with longer progression-free survival ( 7.4 versus 6.1 months ; hazard ratio , 1.57 ; 95 % confidence intervals , 1.17 to 2.09 ; p = 0.002 ) and overall survival ( 19.8 versus 11.1 months ; hazard ratio , 1.57 ; 95 % confidence interval , 1.15-2 .13 ; p = 0.004 ) compared with these in high baseline plasma VEGF-A levels .