Elbasvir Inhibits Hepatitis E Virus Internalization and, in Combination with Ribavirin, Achieves Sustained Viral Suppression In Vitro.

Hepatitis E virus (HEV) infection is generally self-limiting in immunocompetent individuals but may progress to chronic infection in immunocompromised patients, underscoring the need for effective antiviral therapies. Although ribavirin is currently used off-label for HEV treatment, its associated adverse effects highlight the need for safer alternatives. In this study, we screened an anti-viral compound library comprising 800 compounds using three HEV reporter systems designed to target distinct stages of the viral life cycle. Candidate compounds were further evaluated in PLC/PRF/5 cells using both acute and chronic infection models with wild-type genotype 3 HEV (HEV-3). Antiviral activity was assessed by measuring HEV RNA levels in culture supernatants. Elbasvir, a known inhibitor of hepatitis C virus (HCV) non-structural protein 5A (NS5A), was identified as the most potent candidate. Although multiple compounds showed inhibitory effects in reporter assays, only elbasvir achieved sustained suppression of HEV growth in long-term culture, reducing HEV RNA levels to below the limit of detection. In a chronic infection co-culture model, elbasvir maintained antiviral activity at non-cytotoxic concentrations. Time-of-addition analysis demonstrated that elbasvir inhibits an early step in the viral life cycle, specifically viral internalization. Furthermore, combination with ribavirin enhanced antiviral efficacy, resulting in sustained viral suppression without detectable cytotoxicity and exhibiting an additive interaction. Collectively, these findings identify elbasvir as a promising candidate for repurposing as an anti-HEV drug and support a combination strategy targeting distinct steps of the viral life cycle.