Study endpoints and statistical analysis
The primary endpoint of this study was PFS, which was defined as time from the start of therapy to death or progression of disease. Additional endpoints were OS, CR, and overall response rate (ORR), and nonhematologic toxicity. PFS and OS were calculated using Kaplan-Meier estimates, and survival estimates were compared among subgroups of patients using the log-rank test. Responses were assessed as per intention-to-treatment analysis by pretreatment characteristics and compared using Fisher exact test (2-tailed). Difference were considered significant if P was < .05. All analyses were performed on Statistica Version 6.1 (Stat-soft).