Fiacitabine is a synthetic nucleoside analog primarily utilized in antiviral research, particularly for studying treatments against herpes viruses and other DNA viruses. It acts by inhibiting viral DNA polymerase, thereby preventing viral replication. Due to its mechanism, it has also been investigated in preclinical studies for potential anticancer applications, such as in acute myeloid leukemia (AML) and lymphomas, where it interferes with DNA synthesis in rapidly dividing cells. Its use is mainly in laboratory settings and early-stage trials to evaluate efficacy, mechanism of action, and safety, often in combination with other agents. It is not approved for clinical treatment and requires careful handling in research environments.