Impact of metformin on HBV replication: No evidence of suppression in vitro.

BACKGROUND: Outcomes of chronic Hepatitis B (CHB) infection have been increasingly associated with various metabolic syndromes, including metabolic-dysfunction associated steatotic liver disease (MASLD), with a potential for impact on liver disease progression. There is some evidence that metformin, a widely used anti-diabetic drug, may reduce hepatocellular carcinoma (HCC) incidence in people living with Hepatitis B Virus (HBV), but with little to no evidence of impact on the virus itself in vivo. However, previous in vitro studies suggest metformin may have a direct impact on HBV replication, although the mechanism remains unclear. OBJECTIVES: We aimed to investigate the impact of metformin on HBV replication in vitro. STUDY DESIGN: Hepatocyte cell lines constitutively expressing HBV (HepAD38) were treated once or thrice with escalating doses of metformin, using lamivudine and water as controls. We monitored cellular cytotoxicity as well as HBV biomarkers (HBeAg, HBsAg, HBV DNA and RNA) throughout the assay. RESULTS: We did not observe any impact of metformin on HBV replication after a single dose or three repeated treatments. CONCLUSIONS: In HepAD38 cells, HBV replication is not impacted by metformin treatment. This contrasts with prior in vitro data but is in line with clinical evidence that suggests metformin acts through an influence on liver disease progression rather than a direct antiviral impact on HBV itself.