Virological breakthrough after immune checkpoint inhibitor and nucleos(t)ide analog treatment in patients with hepatitis B surface antigen positive hepatocellular carcinoma: a real-world study

Background Immune checkpoint inhibitors (ICIs) have been shown to be a promising and effective treatment for hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC). However, there is a lack of evidence-based data demonstrating the impact of ICIs on HBV DNA level in HBV-HCC patients undergoing nucleos(t)ide analog (NA) therapy and of HBV DNA variation on patient survival. In this study, we aimed to investigate this issue in the real world. Methods In this single-center retrospective study, we reviewed 182 baseline hepatitis B surface antigen (HBsAg)-positive HBV-HCC patients who were treated with ICIs and pre-emptive NAs. The demographic characteristics, tumor status, treatments, HBV DNA, HBsAg, liver function, antitumor response, and patient survival were investigated. The primary endpoints were the virological breakthrough (VB) rate, HBV reactivation (HBVr) rate, and long-term HBV DNA control; the secondary endpoints were the overall survival (OS) and progression-free survival (PFS). Results (1) VB and HBVr occurred in 18.1% (33/182) and 4.4% (8/182) of patients with a median occurrence time of 3.9 months (range, 0.7-16.0) and 8.0 months (range, 3.0-16.0), respectively. The HBV DNA negative rates were 26.1% and 0 at 24 and 48 weeks in the VB group and 12.5% and 0 in the HBVr group, respectively. A baseline HBsAg level >= 200 IU/mL was the only risk factor for VB (OR 9.9, 95% CI 2.2 to 45.2, p=0.003); (2) patients with VB had much shorter median OS and median PFS than those without (12.3 months vs 18.1 months, p=0.035; 4.5 months vs 7.5 months, p=0.011). Conclusions There was a high risk of VB and a moderate risk of HBVr in HBsAg-positive HBV-HCC patients (with poor long-term HBV DNA control) undergoing ICI and pre-emptive NA therapies. The only risk factor for VB was the pretreatment HBsAg level. Further, VB might be considered as a clinical biomarker predicting inferior OS and PFS in the patients.