QKY-613 is a prodrug that enhances immune surveillance by targeting nucleic acid modification pathways. QKY-613 promotes the selective incorporation of 6mdA (N6-methyldeoxyadenosine) into viral DNA, enhancing the phase separation potential of DNA, thereby increasing the activation of cGAS and strengthening host immune surveillance. In virus-infected mouse models, QKY-613 significantly reduced mortality in aged mice. QKY-613 holds promise for research on nucleic acid modification-based immune surveillance mechanisms.