Atezolizumab plus bevacizumab in Child-Pugh B advanced hepatocellular carcinoma patients

397 Background: Atezolizumab plus bevacizumab (Ate/Bev) demonstrated promising efficacy and safety in patients with advanced hepatocellular carcinoma (aHCC) in the phase III IMbrave 150 trial. However, despite the high unmet need in Child-Pugh B patients, this subgroup of patients was not included in this study. Therefore, we aimed to investigate the efficacy and safety of Ate/Bev in Child-Pugh B HCC patients. Methods: This multicenter retrospective study included 27 HCC patients classified as Child-Pugh B who received Ate/Bev at four cancer referral centers between May 2020 and August 2021. Comparative analyses were performed with an independent cohort of Child-Pugh A patients from the same registry (n=130). Results: All patients received Ate/Bev as first-line systemic treatment for aHCC. The objective response rates of patients in Child-Pugh groups B and A were 14.8% and 32.3%, and the disease control rates were 55.5% and 76.1%, respectively. The median progression-free survival (PFS) and overall survival (OS) were 3.0 months (95% CI, 1.6-4.3) and 6.0 months (95% CI, 4.9-7.0) in Child-Pugh B patients, while the median PFS was 6.0 months (95% CI, 4.6-13.4) and the median OS was not-reached (95% CI not available) in Child-Pugh A group. Compared to Child-Pugh A group, grade 3-4 adverse events (AEs) were more common in the Child-Pugh B group (48.1% vs 17.7%, p=0.001), with the most frequent grade 3-4 AEs being thrombocytopenia (11.1%) and AST elevation (11.1%). The rate of treatment discontinuation due to AEs was higher in the Child-Pugh B group (14.8% vs 3.1%, p=0.030), and the reasons for discontinuation were gastrointestinal (GI) bleeding (n=2), GI perforation (n=1) and interstitial pneumonitis (n=1). Conclusions: In the Child-Pugh B subgroup of patients with aHCC, Ate/Bev treatment showed modest clinical activity. However, due to the increased frequency of serious AEs, careful evaluation of treatment response and AE management is required in this subgroup patients. [Table: see text]