Kaplan-Meier estimates of RS survival according to the RS score. The RS score is calculated by adding one point for each of the following risk factors: ECOG PS > 1, LDH > 1.5 ULN, platelet count < 100 × 10⁹/L, tumor size > 5 cm, and number of prior CLL therapies > 1. RS score 0-1: events/N, 14/34; median survival, 62.5 months; 95% CI, 19.4-105.6 months. RS score 2: events/N, 11/15; median survival, 11.0 months; 95% CI, 1.9-20.0 monhts. RS score 3: events/N, 20/24; median survival, 10.5 months; 95% CI, 0.7-20.3 months. RS score 4-5: events/N, 8/9; median survival, 3.8 months; 95% CI, 0-11.1 months.