cyclophosphamide + filgrastim + fluorouracil + mitoxantrone

This is a combination regimen consisting of four agents: - Cyclophosphamide, an alkylating agent that crosslinks DNA, leading to cell death. - Filgrastim, a recombinant human granulocyte colony-stimulating factor (G-CSF) that stimulates the production of neutrophils and is used to reduce the risk of infection due to neutropenia caused by chemotherapy. - Fluorouracil (5-FU), an antimetabolite that inhibits thymidylate synthase, disrupting DNA synthesis and function. - Mitoxantrone, an anthracenedione antineoplastic agent that intercalates into DNA and inhibits topoisomerase II. This combination has been studied in advanced or metastatic breast cancer. Filgrastim is included specifically to support higher-dose chemotherapy regimens by mitigating neutropenia. The regimen aims for increased cytotoxic efficacy while managing hematologic toxicity with growth factor support[2][3][7].