HBV Surface Antigen (subtype adw2, mutation D144A)

Generally, reactivation of hepatitis B virus (HBV) infection is induced by the administration of immunosuppressants or anticancer agents, but reactivation without such drugs has rarely been reported. Here we report an elder case with spontaneous reactivation of HBV replication accompanied by hepatitis B surface antigen (HBsAg) mutations. A 69-year-old man with a history of diabetes mellitus and chronic kidney disease (CKD) was found to be positive for HBsAg (0.072 IU/ml) in June 2018. In May 2019, marked hepatic dysfunction and increased HBsAg (2533.2 IU/ml) were observed when he visited the hospital due to diarrhea and worsening of CKD. At that time, hepatitis B surface antibody (HBsAb) was positive (268.9 mIU/ml) and HBV DNA was 6.0 log IU/ml. After treatment with entecavir, HBV DNA and HBsAg rapidly decreased. Full-genome HBV sequence analysis revealed that the patient was infected with HBV of subgenotype B1 and it had an "a" determinant mutation M133L in the S gene coding HBsAg. Notably, both HBsAg and HBsAb were positive at the time of HBV reactivation, suggesting that the HBV with these mutations escaped from neutralization by HBsAb. This case suggests that immune escape mutations could play an important role in spontaneous HBV reactivation.

Real-world results of nivolumab monotherapy against HCC are lacking in the hepatitis B virus (HBV)-endemic, Asia-Pacific regions. Moreover, heterogeneous responses to immune checkpoint inhibitors have rarely been described in advanced HCC. The aim of this study is to evaluate the efficacy and safety of nivolumab monotherapy in a real-world setting in 33 Korean patients with unresectable HCC. In our cohort, twenty-nine patients (88%) showed HBsAg positivity. At the time of nivolumab initiation, 4 among 33 patients (12%) were classified as Barcelona Clinic Liver Cancer (BCLC)-B stage and 29 (88%) as BCLC-C stage, respectively. Prior sorafenib treatment was given to 31 (94%) patients, and 13 (39%) received prior regorafenib treatment. For the liver reserve, patients were classified as Child-Pugh class A (79%) and B (21%), respectively. Grade 3 toxicities occurred in one patient, who developed pneumonitis after 5 cycles of nivolumab treatment. Best overall responses were complete response in 2 patients out of the 33 enrolled patients (6%), partial response in 4 patients (12%) and stable disease in 4 patients (12%). With 29 patients having images for the response evaluation, the objective response rate was 21.4%. The median overall survival (OS) of the cohort was 26.4 weeks (range 2.3-175.1). Achieving objective responses, pre-treatment small tumors (maximal diameter <5 cm) and favorable liver function as assessed by Albumin-Bilirubin grade were significant factors for the favorable OS. Interestingly, differential responses to nivolumab among multiple tumors in a single patient were noted in 6 patients (18%). In these patients, small metastatic tumors were regressed, although their larger tumors did not respond to nivolumab monotherapy. In summary, nivolumab treatment seems clinically efficacious in treating unresectable HCC in an endemic area of HBV infection. Further prospective evaluation is required to overcome the heterogeneous efficacy of nivolumab monotherapy according to the baseline tumor burden.