Human IDE peptide

Nucleos(t)ide analogues (NAs) have been widely used for the treatment of chronic hepatitis B (CHB). Because viral DNA polymerase lacks proofreading function (3' exonuclease activity), theoretically, the incorporated NAs would irreversibly terminate viral DNA synthesis. This study explored the natures of nascent hepatitis B virus (HBV) DNA and infectivity of progeny virions produced under NA treatment. HBV infectivity was determined by infection of HepG2-NTCP cells and primary human hepatocytes (PHHs). Biochemical properties of HBV DNA in the progeny virions were investigated by qPCR, northern blotting, or Southern blotting hybridization, sucrose gradient centrifugation, and in vitro endogenous DNA polymerase assay. Progeny HBV virions produced under NA treatment were mainly not infectious to HepG2-NTCP cells or PHHs. Biochemical analysis revealed that under NA treatment, HBV DNA in nucleaocapsids or virions were predominantly short minus-strand DNA with irreversible termination. This finding was supported by the observation of first disappearance of relaxed circular DNA and then the proportional decline of HBV-DNA levels corresponding to the regions of PreC/C, S, and X genes in serial sera of patients receiving NA treatment. Conclusion: HBV virions produced under NA treatment are predominantly replication deficient because the viral genomes are truncated and elongation of DNA chains is irreversibly terminated. Clinically, our results suggest that the viral loads of CHB patients under NA therapy vary with the different regions of genome being detected by qPCR assays. Our findings also imply that NA prevention of perinatal and sexual HBV transmission as well as infection of transplanted livers works not only by reducing viral loads, but also by producing noninfectious virions.

Objective Although most patients with chronic hepatitis B (CHB) reach effective virological suppression with long-term nucleos(t)ide analogues (NA) therapy, some might not need to continue treatment for life. In this randomised, controlled, phase IV trial, we evaluated off-therapy outcomes in patients after discontinuing long-term NA therapy. Design Patients who had received NA therapy for >= 1 year and achieved virological suppression (hepatitis B e antigen (HBeAg) seroconversion combined with undetectable hepatitis B virus (HBV) DNA >= 12 months in HBeAg-positive patients or undetectable HBV DNA >= 36 months in HBeAg-negative patients) were randomised 2:1 to stop or continue NA therapy for 72 weeks. Sustained disease remission (HBeAg negative, HBV DNA <2000I U/mL and normal alanine aminotransferase (ALT)) was evaluated at 72 weeks after stopping NA therapy. Results Among 67 enrolled patients, sustained disease remission was observed in 13/45 (29%) stop versus 18/22 (82%) continue patients. Hepatitis B surface antigen (HBsAg) loss occurred in two patients (one in each group). The median HBsAg decline from randomisation to week 72 was similar in both groups (0.2 (0.0-0.4) vs 0.1 (0.0-0.2) log IU/mL in stop vs continue patients). Among patients who stopped, 15/45 (33%) had virological or biochemical relapse and 17/45 (38%) were retreated according to predefined criteria. A total of 11/18 (61%) pretreatment HBeAg-positive versus 6/27 (22%) HBeAg-negative patients required retreatment (p=0.01). Fourteen (31%) patients developed ALT >10x upper limit of normal (ULN) and another 7 (16%) had ALT >5x ULN. No patients experienced liver decompensation or died. Conclusion The findings of this prospective study suggest limited benefit of stopping NA therapy in chronic hepatitis B.