Real-world (RW) experience with atezolizumab + bevacizumab (A+B) for the treatment of unresectable HCC (uHCC): A multicenter study.

537Background: A+B is the preferred first-line (1L) standard of care for uHCC, with emerging RW evidence supporting its use in a broad patient (pt) cohort. We evaluated pt characteristics, clinical and treatment outcomes in pts treated at five U.S. institutions: Mayo Clinic, Houston Methodist, Moffitt Cancer Center, Mays Cancer Center, and University of Arizona. Methods: This is a retrospective study of uHCC pts who initiated A+B after January 1, 2019. De-identified pt data were extracted by treating oncologists. Overall survival (OS) and real-world progression-free survival (rwPFS) were assessed using Kaplan-Meier methods for all pts and for a “trial-like” subgroup with characteristics similar to those in the IMbrave150 trial (ECOG performance status [PS] 0-1, Child-Pugh [CP] class A, albumin-bilirubin [ALBI] grade 1-2). HCC-related hospitalizations were evaluated within 1 year of A+B initiation. Results: A total of 300 eligible pts were treated with 1L A+B (median age 68 years, 79 79 82 4412% ECOG PS gt;1). Liver function was CP A in 7336, 31, 6, CP B in 2615, 7, 5), and CP C in 2 (lt;1 pts. Compared with CP A, more CP B pts had characteristics of compromised liver function (CP A vs B: cirrhosis: 611 ascites: 76 encephalopathy: 47 esophageal varices: 142, bile duct invasion (21, and ECOG PSgt;1 (82, all Pslt;0.001. Over a median follow-up of 8.7 mos, 244 (81 pts discontinued A+B, primarily due to disease progression. Toxicity-related treatment discontinuation and hospitalizations due to treatment-related adverse events (TRAE) were similar between the two groups (Table). Median OS (mOS) was 14.4 mos (95 12.3, 18.2) and median rwPFS was 6.8 mos (95 5.8, 8.4). In the trial-like subgroup (n=194), mOS was 19.5 mos (95 14.6, 24.7) and median rwPFS was 8.8 mos (95 7.6, 12.1). In the CP B subgroup, mOS was 5.6 mos (95 4.6, 11.3) and median rwPFS was 3.1 mos (95 2.4, 5.8). Conclusions: This study demonstrates the RW outcomes of 1L A+B in a diverse pt cohort. Results from the “trial-like” pts further confirm the reproducible efficacy of A+B in clinical practice. Although pts with CP-B had higher hospitalization rates due to disease progression or symptoms, consistent with their underlying liver complications, they had similar rates of toxicity-related treatment discontinuation and TRAE-related hospitalizations compared to CP-A. Further characterization of safety for A+B in CP B pts within a prospective, controlled trial is warranted.N (CP A (n=219)CP B (n=79)Treatment discontinuation*167 (76)75 (95)Atezolizumab-related toxicity20 (12)13 (17)Bevacizumab-related toxicity26 (16)16 (21)Hospitalization*87 (40)58 (73)Symptom-related42 (48)35 (60)Progression8 (9)11 (19)TRAE7 (8)6 (10)*P-value comparing CP A vs CP B lt;0.001.