Tezacitabine is a cytostatic and cytotoxic antimetabolite and a nucleoside analogue with a dual mechanism of action that irreversibly inhibits ribonucleotide reductase and can be incorporated into DNA during replication or repair, causing DNA chain termination. It blocks tumor cells in the G1 and S phases of the cell cycle, inducing apoptotic cell death, with potential applications in treating leukemia and solid tumors[1][2].