cytarabine + methotrexate + trastuzumab

This is a combination regimen consisting of three distinct drugs—cytarabine, methotrexate, and trastuzumab. Cytarabine and methotrexate are both antimetabolite chemotherapeutic agents commonly used in the treatment of hematologic malignancies such as leukemia and lymphoma. Trastuzumab is a monoclonal antibody targeting the human epidermal growth factor receptor 2 (HER2), primarily used in HER2-positive breast and gastric cancers. While cytarabine plus methotrexate combinations are established regimens for certain lymphomas (notably primary central nervous system lymphoma), the addition of trastuzumab would be considered investigational or off-label unless specifically indicated for tumors with HER2 overexpression. Each component acts via a different mechanism to inhibit cancer cell proliferation or survival.