CI-898 HCl is a lipophilic antifolate inhibitor of dihydrofolate reductase (DHFR). It has enhanced binding to DHFR in the presence of the cofactor NADPH. Cl-898 HCl inhibits cell growth and halts the cell cycle at the G1/S phase in L1210 mouse lymphocytic leukemia cells and is active against methotrexate-resistant cancer cell lines. It also enhances the activity of doxorubicin, cyclophosphamide, and 6-thioguanine (6-TG) in mice with advanced stage P338 leukemia.
