Progression-free survival according to randomization. Seventy-nine (46.2%) of 171 patients treated with fludarabine had progressive disease, according to the NCI criteria, compared with 53 (31.5%) of 168 patients treated with FC, in whom disease progressed. Median progression-free survival was 20 months in the monotherapy arm and 48 months in the combination therapy arm (P = .001).