Abstract A037: FLIPI24 stratifies outcomes in follicular lymphoma treated with R2-based therapy: A pooled MD Anderson trial cohort

Abstract Background: Follicular lymphoma (FL) is the most common indolent lymphoma and remains incurable with standard therapy, with marked heterogeneity in clinical outcomes. Although FLIPI24 was developed in a large cohort to predict lymphoma-related mortality, its ability to predict treatment response and progression-free survival (PFS) in patients receiving contemporary immunotherapy, including rituximab plus lenalidomide (R2)-based regimens, has not been well characterized. Methods: We pooled data from three investigator-initiated trials conducted at MD Anderson Cancer Center: R2 (NCT00695786; n = 79), ibrutinib plus R2 (NCT02532257; n = 38), and obinutuzumab plus lenalidomide (NCT02871219; n = 90). The primary objective was to assess end-of-induction complete response (CR), CR at 30 months (CR30), PFS, and overall survival (OS), stratified by FLIPI24 risk. Results: A total of 207 patients were included (median age, 57 years; range, 29-84). By FLIPI24, 48%, 39%, and 13% of patients were classified as low, intermediate, and high risk, respectively. End-of-induction CR rates were similar across FLIPI24 groups (91% vs 90% vs 83%). In contrast, high-risk FLIPI24 was associated with significantly lower CR30 compared with low- and intermediate-risk patients (59% vs 79% vs 84%; p = 0.044). After a median follow-up of 9.1 years, high-risk FLIPI24 was associated with inferior PFS (5-year PFS: 58% vs 79% vs 79%; p = 0.049), while no significant differences in OS were observed. Conclusion: FLIPI24 is a robust prognostic model for predicting outcomes in patients receiving R2-based first-line therapy and the study results may serve as a reference framework for future clinical trials. Citation Format: Dai Chihara, Zhiping Luo, Ruitao Lin, Christopher R. Flowers. FLIPI24 stratifies outcomes in follicular lymphoma treated with R2-based therapy: A pooled MD Anderson trial cohort [abstract]. In: Proceedings of the Fifth AACR International Meeting on Advances in Malignant Lymphoma: From Discovery to Clinical Impact; 2026 Jun 24-27; Philadelphia, PA. Philadelphia (PA): AACR; Blood Cancer Discov 2026;7(3_Suppl):Abstract nr A037.