Numbers of subchromosomal losses for each patient were determined using 50kXbal SNP array technology and a sliding window algorithm (the 8/7/1.45 rule) applied to dChip-based copy number estimates as described in “Derivation of a genomic complexity score, Algorithmic method.” Multivariate analysis was performed using Cox proportional hazards models. Modeling was performed separately using the 139 first treatment events for TTFT, and the 48 subsequent treatment events for TTST. All models included algorithmic genomic complexity based on losses only. The TTFT analysis included as binary covariates ZAP-70⁺, IgV_H status unmutated, Rai stage (coded as stage 1/2 vs 0), presence of either del11q or del17p,_presence of p53 exon 5-9 mutations and CD38 expression in > 30% of CD5⁺/CD19⁺ cells. The same factors except Rai stage were considered in the multivariate analysis for TTST. Models were interpreted based on the hazard ratio estimates for factors of interest and their P values.