Atezolizumab plus bevacizumab treatment for unresectable hepatocellular carcinoma progressing after molecular targeted therapy: A multicenter prospective observational study.

To evaluate the efficacy of atezolizumab plus bevacizumab treatment in patients with hepatocellular carcinoma (HCC) previously treated with molecular targeted agents (MTAs). Thirty-one patients treated with atezolizumab plus bevacizumab for unresectable HCC and previously treated with MTAs were enrolled in this study. The treatment lines ranged from second to sixth lines. The treatment effect on HCC differed from that during first-line treatment. The treatment effect was determined using the Response Evaluation Criteria in Solid Tumors (RECIST) and modified RECIST. The treatment response was different for each MTA immediately prior to atezolizumab + bevacizumab treatment. Tumors treated with lenvatinib followed by atezolizumab + bevacizumab showed rapid growth for a short period of time followed by shrinkage. However, patients who received ramucirumab, sorafenib, and regorafenib did not show such changes. This was likely because of differences in the mechanism of action of the MTA administered immediately beforehand. The side-effect profile differed from that observed in the IMbrave150 phase 3 study of atezolizumab plus bevacizumab, which showed more adverse events related to hepatic reserve. Patients treated with the combination of atezolizumab and bevacizumab after lenvatinib therapy may experience rapid tumor growth and subsequent shrinkage.