Long-Term Survival Analysis of the North American Intergroup Study C9011 Comparing Fludarabine (F) and Chlorambucil (C) in Previously Untreated Patients with Chronic Lymphocytic Leukemia (CLL).

Abstract

Abstract Abstract 536 Long-term outcomes following novel therapies for CLL have rarely been reported. Between 10/90 and 12/94, 509 eligible, untreated patients (pts) with symptomatic CLL were enrolled by 4 cooperative groups onto study C9011; 179 were randomized to F, 193 to C, and 137 to F+C. After slightly more than 5 years median follow up, with the time of last follow-up in June 1999, we reported in 2000 (NEJM 343:1750) that F provided significantly higher response rates and longer remission duration and progression-free survival (PFS) than C (p<0.001 for all 3 endpoints). The combination arm with F+C was stopped early because of high morbidity and mortality. There was no difference in overall survival (OS) among the 3 groups. Nearly 10 years have now elapsed since this report. Therefore, with the time of last follow-up in January 2009, we analyzed the long term outcomes of pts enrolled on the study. PFS was defined as the time between randomization and the occurrence of progressive disease or death due to any cause. Results: Of the 509 pts, 85% have now died; among pts on the F and C arms, 92% have progressed. We found that F treatment resulted in significantly longer PFS than did C (p < 0.001), with notable differences in PFS at 2, 3, and 4 years (Table). While the F and C arms had the same OS during the initial 5 years following randomization, our current analysis with longer follow-up shows that pts treated on the F arm had better survival than did those on the C arm during the ensuing years (Figure). The p-values for this difference are 0.04 (unadjusted for covariates) and 0.07 (covariate-adjusted). The emergence of improved survival following initial F treatment, appearing only after 5-6 years, is an unexpected and noteworthy finding. Reporting second malignancies was required on this study. There were 27 epithelial cancers reported (9 on F, 11 on C, 7 on F+C), involving colon, lung, breast, prostate, pancreas, liver, bladder and skin (6 squamous, 2 melanoma). Seven therapy-related myeloid neoplasms (t-MN) were reported; 6 were on F+C; 1 on F. Richter's transformation to non-Hodgkin lymphoma was reported in 34 pts; prolymphocytic leukemia occurred in 10; Hodgkin lymphoma in 6; myeloma in 2; hairy cell leukemia in 1. These cases were distributed with 18 on F, 18 on C, and 17 on F+C. Thus, the overall incidence of second malignancies reported was 17%. Conclusion: Initial treatment with F provides better long-term outcomes than initial treatment with C. Second malignancies are common, but the overall incidence is not increased on the F-containing treatment arms except for t-MN. Disclosures: No relevant conflicts of interest to declare.