ONX 0801 (BGC 945) trisodium is a targeted thymidylate synthase (TS) inhibitor specifically designed to act against tumors overexpressing the α-folate receptor.

ONX 0801 (BGC 945) is designed to further reduce toxicity by more effectively targeting cancer cells that overexpress the α-FR[1]. ONX 0801 (BGC 945) exhibits IC 50 values of of 6.6 μM, 1.1 nM, 3.3 nM, 90 nM and 0.32 μM in A431, A431-FBP, KB, IGROV-1 and JEG-3 cells[2].

BGC 945 (100 mg/kg, ip/iv injection) in the tumor had a longer half-life (28 hours) compared with other tissues[2]. BGC 945 (100 mg/kg daily for 16 days) does not lead to body weight loss, macroscopic signs of toxicity to the major organs, or a change in renal function[2]. BGC 945 at 100mg/kg induces a 5-20-fold increase in tumor dUrd at 4-72h without increases in the plasma, consistent with tumor targeting[2]. Animal Model: Mice (on the folate-free diet for 5 days were transplanted with tumor and the implants)[2]. Dosage: 100 mg/kg (Pharmacokinetic Analysis). Administration: Single i.p. or iv injection. Result: After i.p. injection, the compound was well absorbed from the peritoneal cavity. The plasma AUC was 50% higher for i.p. compared with i.v. administration and was also higher in spleen, kidney, and liver by this route. Tumor AUC was similar via either route.