Prognostic significance of the follicular lymphoma international prognostic index (FLIPI) in the E1496 trial of chemotherapy with or without maintenance rituximab

Abstract

6526 Background: In the E1496 trial, maintenance rituximab significantly prolonged progression free survival (PFS) after CVP (cyclophosphamide, vincristine, prednisone) chemotherapy in patients (pts) with advanced indolent non-Hodgkin’s lymphoma (Proc ASCO 2004:6502). A new follicular lymphoma international prognostic index (FLIPI) for overall survival (OS) has been recently reported (Blood 2004, 105:1258) in pts treated with conventional therapy but its significance for other endpoints and in the setting of chemo-immunotherapy has not been reported. Methods: The FLIPI score (low=0,1; intermediate=2; poor=3–5) was determined for 297 pts (227 follicular) who received CVP and 239 stable or responding pts (185 follicular) subsequently randomized to observation or rituximab. Correlations with response rate (RR), PFS and OS are reported. Results: The distribution of FLIPI score was 21% low, 32% intermediate (int) and 47% poor risk. FLIPI score correlated with RR to CVP for all pts (RR: 81% low, 74% int, 63% poor risk, p=0.02) and follicular pts (RR: 80% low, 76% int, 64% poor risk, p=0.09). For follicular lymphoma pts, two-year PFS (62% v 47%, p=0.04) and OS (97% v 84%, p=0.05) were shorter in FLIPI high compared to low risk pts after CVP induction. For all pts, FLIPI high compared to low risk resulted in shorter PFS (p=0.09) and OS (p=0.03). The distribution of FLIPI score among maintenance pts was 24% low, 35% int and 41% poor. To date, no difference in PFS and OS were observed according to FLIPI risk group for all pts or for follicular pts in the randomized groups, rituximab or observation. Conclusions: FLIPI score ≥3 was predictive for response to CVP and also for PFS and OS after CVP in the E1496 trial. To date, the FLIPI score in stable and responding pts was not significantly associated with PFS or OS in the observation and maintenance rituximab groups. These data suggest that much of the predicitive power of the FLIPI score is associated with response to induction therapy and indicate the importance of study pt characteristics in the interpretation of clinical results in indolent lymphoma. Author Disclosure Employment or Leadership Consultant or Advisory Role Stock Ownership Honoraria Research Funding Expert Testimony Other Remuneration Genentech