Distinct Characteristics and Changes in Liver Function of Patients with Hepatocellular Carcinoma Treated with Atezolizumab Plus Bevacizumab for More Than 1 Year.

Purpose: Since 2020, atezolizumab plus bevacizumab (Ate/Bev) has been the standard first-line therapy for unresectable hepatocellular carcinoma (HCC), but long-term treatment studies are limited. This study evaluated the clinical characteristics and effects of Ate/Bev for over 1 year.

Materials and methods: This study included patients with unresectable HCC treated with first-line Ate/Bev between May 2020 and April 2022. Those receiving Ate/Bev for 1 year or more were classified as the long-term treatment group.

Results: Of 246 patients, 69 (28.0%) were in the long-term treatment group, which comprised more proportions of intrahepatic tumor burden < 25%, Eastern Cooperative Oncology Group 0, and a lower proportion of portal vein tumor thrombosis than the short-term treatment group. The long-term treatment group had a higher incidence of atezolizumab-related thyroid dysfunction (31.9% vs. 10.7%, p < 0.001; median time to onset [mTTO], 2.8 months), dermatologic toxicity (29.0% vs. 14.7%, p=0.017; mTTO, 3.3 months), bevacizumab-related hypertension (44.9% vs. 22.0%, p=0.001; mTTO, 4.2 months), and proteinuria (69.6% vs. 38.4%, p < 0.001; mTTO, 6.8 months), compared to the short-term treatment group. Regarding liver function in the long-term treatment group, patients initially classified as Child-Pugh class A decreased from 87.0% to 75.4%, and albumin-bilirubin grade 1 decreased from 68.1% to 50.7% after 1 year of treatment.

Conclusion: The Ate/Bev long-term treatment group had a lower intrahepatic tumor burden, less portal vein tumor thrombosis, and better performance status and liver function at baseline. Atezolizumab-related immunological adverse events emerged relatively early in treatment compared to the bevacizumab-related. Additionally, some patients demonstrated liver function deterioration during long-term Ate/Bev treatment.