Secondary end points were consistently improved in the VR-CAP group , including the complete response rate ( 42 % vs. 53 % ) , the median duration of complete response ( 18.0 months vs. 42.1 months ) , the median treatment-free interval ( 20.5 months vs. 40.6 months ) , and the 4-year overall survival rate ( 54 % vs. 64 % ) .