Development of a sensitive, multi-assay platform to monitor low levels of HBV DNA and pgRNA in patients with chronic hepatitis B virus infection

HBV cure rates remain low despite prolonged nucleos(t)ide (NrtI) therapy, likely due to persistent residual viral replication and an inability to eliminate covalently closed circular DNA (cccDNA). Therapies with novel mechanisms of action against hepatitis B virus (HBV) are being explored with the goal of achieving sustained off-treatment response and a functional cure without requiring lifelong therapy. Recent studies have indicated that serum HBV DNA levels (a biomarker for viral replication) combined with serum pregenomic RNA (pgRNA) levels (a surrogate for intrahepatic cccDNA transcriptional activity), may provide a better prediction for the risk of liver-related complications. Current HBV DNA assays, such as the COBAS AmpliPrep/COBAS TaqMan HBV test v2.0, quantitate HBV DNA down to 20 IU/mL, but are not able to monitor loss of residual virus in patients on NrtI therapy. There are no commercially available assays approved to detect serum/plasma HBV pgRNA levels. We have developed a multi-assay panel of highly sensitive nucleic acid assays designed to monitor levels of HBV DNA, pgRNA and total nucleic acids (TNA, composite DNA + pgRNA) in clinical specimens and to monitor changes during treatment with new antiviral combination regimens.