 Statistical analysis Data will be analyzed according to both the intention-to-treat ITT and per protocol PP methods. The baseline characteristics will be expressed in mean SD. The Pearson chi -square test and Fischer exact test will be used for comparison of categorical data as appropriate. The t-test will be used for comparison of continuous variables. Cumulative survival will be estimated using Kaplan-Meier life table analysis, and the groups will be compared by log rank chi-square test. 