ARC-520 + entecavir + pegylated interferon alpha 2a

ARC-520 + entecavir + pegylated interferon alpha 2a is a combination regimen under investigation for **chronic hepatitis B virus (HBV) infection**. - **ARC-520** is a small interfering RNA (siRNA) therapy targeting HBV transcripts derived from covalently closed circular DNA (cccDNA) and integrated HBV DNA, thereby reducing hepatitis B surface antigen (HBsAg), hepatitis B e antigen (HBeAg), and HBV DNA levels through RNA interference[2][4][7]. - **Entecavir** is a nucleoside analogue reverse-transcriptase inhibitor (NUC) that suppresses HBV replication by inhibiting viral DNA synthesis[7]. - **Pegylated interferon alpha 2a** is an immunomodulatory agent that induces antiviral responses and clearance of infected hepatocytes. Combined, these agents act synergistically: entecavir mediates continuous suppression of HBV DNA, ARC-520 transiently but strongly suppresses HBsAg and HBeAg via RNAi, and interferon stimulates immune-mediated clearance[1][5][7]. The combination has been studied in treatment-naïve and NUC-experienced patients with different HBV genotypes, including HBeAg-positive and negative cases, and some cohorts for hepatitis delta virus (HDV)[1][5]. The regimen aims to achieve reductions in HBsAg, promote seroconversion, and potentially enable functional HBV cure[1][2][4].