CHOP + X

CHOP + X refers to a combination chemotherapy regimen based on the standard CHOP protocol, with the addition of an extra agent ("X"). The canonical CHOP regimen includes cyclophosphamide (an alkylating agent), doxorubicin (an anthracycline), vincristine (a vinca alkaloid), and prednisone or prednisolone (a corticosteroid)[1][2][7]. The "X" in "CHOP + X" denotes an additional drug added to this backbone, which can vary depending on the clinical trial or treatment protocol. Examples of such additions include rituximab (R-CHOP)[2][4], bryostatin 1[3], polatuzumab vedotin, etoposide phosphate (EPOCH regimens)[6], and others. The mechanism of action for CHOP is primarily cytotoxicity against rapidly dividing cells via DNA damage, inhibition of mitosis, and immunosuppression. The added agent ("X") may introduce targeted therapy or another cytotoxic mechanism depending on its identity.