Real world outcomes in patients with follicular lymphoma treated with RCHOP vs BR.

e19038 Background: In patients (pts) with (w) follicular lymphoma (FL), BR is associated w improved progression free survival (PFS) compared to RCHOP. In clinical practice, RCHOP is frequently utilized in pts w grade (G) 1-2 FL w high SUVs or Ki-67% proliferation index, and G 3A FL due to concern for transformation. Using real world data, we compared treatment trends and outcomes in pts w FL treated w first line (1L) BR versus (vs) RCHOP. Methods: This study used the nationwide Flatiron Health electronic health record-derived de-identified database. Pts diagnosed w FL G 1-2 or 3A and treated between (bt) 2011-2022 w 1L BR or RCHOP were included. The primary objective was to compare time to next treatment or death (TTNT) bt the two cohorts. Overall survival (OS), and transformation and POD24 rate were also analyzed. Univariable and multivariable Cox regression models were used to evaluate the impact of various clinical factors (sex, ethnicity, ECOG PS, treatment center type, FL G, FLIPI, rituximab maintenance mtn) on TTNT and OS. Results: The study included 2,089 pts; 1,475 pts received BR (BR n=1387, BO obinutuzumab n=88,), and 614 pts received RCHOP (RCHOP n=459, OCHOP n=8, RCEOP etoposide n=4, RCHP n=1, RCEP n=1, RCVP n=137, OCVP n=4). Median age at diagnosis was 64. Most patients were male (53%), non-Hispanic (90%), had advanced stage disease (82%), ECOG PS 0 (57%), G 1-2 FL (85%), intermediate FLIPI (62%), were treated at a community practice (83%), and did not receive rituximab mtn (54%). At median follow up of 90 mos, median TTNT bt BR and RCHOP was 96 vs 78 mos (HR 1.146, 95% CI 0.986-1.332, p = 0.076). In a multivariable model, there was no significant association bt RCHOP and TTNT. Male sex, ECOG PS ≥ 2, and high FLIPI were associated w worse TTNT, and Rituximab mtn w improved TTNT. Among G 3A pts (n=304), more pts received RCHOP (57% vs 43%), and median TTNT bt BR and RCHOP was 73 vs 78 mos (HR 0.787, 95% CI 0.542-1.142, p=0.207). Median OS bt BR vs RCHOP was 126 vs 138 months (HR 0.878, 95% CI 0.718-1.075, p=0.207). Male sex, ECOG PS ≥ 2, high FLIPI, and treatment in community setting were associated w worse OS. Rituximab mtn was associated w improved OS. 115 (5.5%) pts had transformation to aggressive lymphoma. Transformation rates bt BR vs RCHOP were 4.83% vs 6.50% (p=0.2) among all G 1-2 pts (n=1785), and 3.85% vs 9.2% (p=0.069) among all G 3A pts (n=304). 310 (14.8%) pts had POD 24, including 13.3% of all pts treated with BR and 18.6% with RHCOP (p=0.002). Autologous stem cell transplant (ASCT) was used in 26 (8.4%) POD 24 pts, among whom there was no difference in ASCT rate bt BR vs RCHOP (8.2% vs 8.8%, p=0.9). Conclusions: This retrospective analysis of real-world data showed clinical improvement in TTNT w BR compared to RCHOP in all FL patients. Among patients w G 3A FL, there was no significant improvement in TTNT with RCHOP. Rituximab mtn was associated w improved OS. Rate of transformation was higher in G 3A patients treated with RCHOP. There was low rate of ASCT in POD24 pts.