methotrexate + mitoxantrone + tamoxifen

This is a combination regimen consisting of three drugs—methotrexate, mitoxantrone, and tamoxifen—used primarily in the treatment of advanced or metastatic breast cancer. Methotrexate is an antimetabolite and antifolate agent that inhibits dihydrofolate reductase, leading to suppression of DNA synthesis and cell division. Mitoxantrone is an anthracenedione antineoplastic agent that intercalates into DNA and inhibits topoisomerase II, resulting in cytotoxicity to rapidly dividing cells. Tamoxifen is a selective estrogen receptor modulator (SERM) that competitively inhibits estrogen binding to its receptor, thereby blocking the growth-promoting effects of estrogen on breast cancer cells. This combination leverages both cytotoxic chemotherapy (methotrexate and mitoxantrone) and hormonal therapy (tamoxifen) for synergistic anti-tumor activity[5][6][10]. The regimen has been studied as part of multi-drug protocols for advanced breast cancer in postmenopausal women[1].