thioguanine + bleomycin + fludarabine

This is a combination chemotherapy regimen consisting of three antineoplastic agents—thioguanine, bleomycin, and fludarabine. Each component has a distinct mechanism of action: - **Thioguanine** is an antimetabolite (6-thiopurine analogue) that incorporates into DNA and RNA as a false purine base after intracellular activation, disrupting nucleic acid synthesis during the S-phase of the cell cycle. It is primarily used in the treatment of acute nonlymphocytic leukemias[1][7]. - **Bleomycin** is an antibiotic with antitumor activity that induces DNA strand breaks through free radical formation. - **Fludarabine** is also an antimetabolite; it inhibits DNA polymerase alpha, ribonucleotide reductase, and DNA primase after conversion to its active triphosphate form inside cells. This results in inhibition of DNA synthesis and cell death[4][10]. This combination would be expected to have synergistic cytotoxic effects on rapidly dividing malignant cells by targeting different aspects of nucleic acid metabolism and integrity.