Lonsurf

【 Mechanism of Action 】 LONSURF is based on thymidine analogues, triflurouridine, and thymidine phosphorylase inhibitor, tipiracil, with a molar concentration ratio of 1:0.5 (weight ratio, 1:0.471). Including tipiracil inhibiting its metabolism through thymidine phosphorylase and increasing the exposure of triflurouracil.

After ingesting cancer cells, trafloxuridine is back doped into DNA, which interferes with DNA synthesis and inhibits cell proliferation. Trifluuridine /tipiracil showed antitumor activity against wild-type and mutant human colorectal cancer of KRAS in xenograft mice.

[Indications and uses] LONSURF is suitable for patients with metastatic colorectal cancer who have been treated with chemotherapy based on fluorouracil-,oxaliplatin-and irinotecan, an anti -VEGF biological therapy, and an anti -EGFR therapy such as RAS wild type.

[Formulation and specifications] Tablets; 15 mg trafloxuridine /6.14 mg tipiracil; 20 mg trafloxuridine /8.19 mg tipiracil

[Dosage and Administration Method]

⑴ Recommended dose: take 28 days as a course of treatment, and take it twice a day from the first day to the fifth day and the eighth day to the twelfth day. The dose is 35mg/㎡, and the maximum dose is 80mg.
⑵ Take the medicine 1 hour after breakfast or dinner.
⑶ Don’t take extra dose after losing dose or on the basis of original dose.

[Adverse reactions] The most common adverse reactions (≥10%) are anemia, neutropenia, weakness/fatigue, nausea, thrombocytopenia, anorexia, diarrhea, vomiting, abdominal pain, and fever.

“Used in special people”
(1) Medication during pregnancy: According to animal data and its mechanism of action, LONSURF can cause fetal harm. Advise pregnant women about the potential risks to the fetus.
(2) Medication in lactation: There is no data to evaluate the effects of LONSURF or its metabolites on breast-feeding or milk production. Because of its potential for serious adverse reactions in breast-feeding infants, women are advised not to breastfeed during the treatment with LONSURF and the day after the final dose.
(3) Medication for women and men with reproductive potential: advise women with reproductive potential to use effective contraception during treatment. Because of the potential for genotoxicity, men with reproductive potential female partners are advised to use condoms during treatment with LONSURF and to use contraception for at least 3 months after the final dose.