Besifovir is primarily used in the treatment of chronic hepatitis B virus (HBV) infection. It functions as a nucleotide analog that inhibits viral DNA synthesis by targeting the HBV polymerase enzyme, thereby suppressing viral replication. Due to its high potency and favorable resistance profile, it offers a therapeutic option for patients who may not respond well to other antiviral agents. Besifovir has shown improved renal safety compared to older antivirals, making it suitable for long-term administration. It is under clinical development and has demonstrated effective reduction of HBV DNA levels in serum, with potential for use in both HBeAg-positive and HBeAg-negative chronic hepatitis B patients.