methotrexate + thiotepa + dexamethasone + idarubicin + cytarabine

This regimen is a **multi-agent chemotherapy combination** containing five small-molecule antineoplastic drugs: methotrexate, thiotepa, dexamethasone, idarubicin, and cytarabine. Each drug exerts distinct but often synergistic anti-cancer effects. - **Methotrexate** is an antimetabolite and antifolate that inhibits dihydrofolate reductase, leading to impaired DNA synthesis. - **Thiotepa** is an alkylating agent that crosslinks DNA, inhibiting replication and transcription. - **Dexamethasone** is a synthetic glucocorticoid with anti-inflammatory and cytotoxic effects on lymphoid cells. - **Idarubicin** is an anthracycline that intercalates DNA and inhibits topoisomerase II, promoting apoptosis. - **Cytarabine** is a pyrimidine analog antimetabolite that inhibits DNA polymerase, primarily affecting rapidly dividing cells. This intensive regimen is used in specific hematological malignancies, particularly some high-risk lymphomas and leukemias, including situations where central nervous system (CNS) involvement or aggressive disease requires multi-drug combination therapy. This specific combination resembles modifications or intensifications of established regimens such as MATRIx or other high-dose CNS lymphoma or leukemia protocols.