envofolimab + irinotecan + leucovorin calcium + 5-fluorouracil

Envofolimab + irinotecan + leucovorin calcium + 5-fluorouracil is a multi-drug combination therapy, presumably developed for the treatment of advanced or metastatic solid tumors, most notably colorectal cancer. This regimen combines: - **Envofolimab**, a monoclonal antibody PD-L1 checkpoint inhibitor, believed to block the interaction between PD-L1 and PD-1, thereby enhancing the body's immune response against tumors (mechanism inferred from general PD-L1 inhibitors, as no specific trial information is retrieved for envofolimab in this exact combination). - **Irinotecan**, a small molecule that inhibits topoisomerase I, causing DNA damage and apoptosis in dividing cancer cells[2][3]. - **Leucovorin calcium** (folinic acid), a biomodulator used to enhance the efficacy of fluorouracil by stabilizing the binding between 5-fluorouracil and thymidylate synthase[3]. - **5-fluorouracil**, a small molecule pyrimidine analog antimetabolite that irreversibly inhibits thymidylate synthase, thereby suppressing DNA synthesis in rapidly dividing cells[2][3]. This combination likely aims to leverage direct cytotoxic effects of chemotherapy with immune checkpoint blockade. Regimens with irinotecan, leucovorin calcium, and 5-fluorouracil are established as "FOLFIRI" in colorectal cancer; addition of envofolimab is a novel investigational variant designed to further enhance anti-tumor activity via immunotherapy.