What are the effects of trifluridine and tipiracil tablets (Lonsurf)?

Trifluridine and tipiracil tablets (Lonsurf) are composed of the thymidine-based nucleoside analog trifluridine and the thymidine phosphorylase inhibitor tipiracil, with a molar ratio of 1:0.5 (weight ratio of 1:0.471). Inhibiting the metabolism of trifluridine by thymidine phosphorylase, inclusion of tipiracil increases trifluridine exposure. After being taken up by cancer cells, tipiracil is integrated into DNA, interfering with DNA synthesis and inhibiting cell proliferation. Trifluridine/tipiracil demonstrated antitumor activity against KRAS wild-type and mutant human colorectal cancer xenografts in mice.