Risk of HBV reactivation in patients with immune checkpoint inhibitor-treated unresectable hepatocellular carcinoma

BACKGROUND: Immunotherapy with immune checkpoint inhibitor (ICI) is a promising treatment for unresectable hepatocellular carcinoma (HCC). However, whether ICIs would have the risk of hepatitis B virus (HBV) reactivation and the necessary of nucleos(t)ide analogs (NUCs) prophylaxis are still unclear. We aimed to investigate the role of NUCs prophylaxis in HBV-infected patients who underwent ICIs treatment. METHODS: The study was a retrospective prospective design to review and follow-up consecutive 62 patients with chronic hepatitis B or resolved HBV infection who had received ICIs treatment for the unresectable HCC. Of them, 60 patients with documented baseline serum HBV DNA value were classified into three categories according to the baseline HBV viral load and the status of antiviral therapy before ICI treatment. The clinical status, including tumor response, viral kinetics and liver function, was recorded and investigated. RESULTS: No HBV reactivation occurred in the 35 patients with HBV DNA ≤100 IU/mL on NUCs therapy. Of the 19 patients with HBV DNA >100 IU/mL who started NUCs simultaneously with ICI treatment, none encountered HBV reactivation during the immunotherapy. Of the six HBV patients without NUCs treatment, three had a greater than 1 log decrease in HBV viral load, and one maintained his serum HBV DNA in undetectable status during ICI treatment. Eventually, one out of six experienced HBV reactivation after 9 weeks of ICI treatment. CONCLUSION: No patients on antiviral therapy developed HBV reactivation, and one out of six not receiving antiviral therapy had HBV reactivation. HBV viral load higher than 100 IU/mL is safe and not a contraindication for ICI treatment for HCC, if NUCs can be coadministrated.