Lonsurf combines trifluridine, an antineoplastic thymidine-based nucleoside analogue, with tipiracil hydrochloride, a thymidine phosphorylase inhibitor, in either 15mg/6.14 mg or 20mg/8.19mg tablets.
Trifluridine is incorporated into cellular DNA via phosphorylation, thereby disrupting DNA function and cellular proliferation. Tipiracil hydrochloride prevents the normal degradation of trifluridine by thymidine phosphorylase.
Lonsurf is indicated in patients who have been previously treated with, or who are not considered candidates for, available treatments (including fluoropyrimidine-, oxiplatin- or irinotecan-based chemotherapies, anti-VEGF agents and anti-EGFR agents).
Findings of the RECOURSE study (n=800) showed trifluridine/tipiracil to be superior to placebo in treating patients with metastatic colorectal cancer who were refractory to or unable to tolerate standard chemotherapies. Participants were randomised to receive either trifluridine/tipiracil (n=534) or placebo (n=266), both with best supportive care.
Median overall survival, the primary endpoint, was 7.1 months (95% CI 6.5-7.8) in the trifluridine/tipiracil group compared with 5.3 months (95% CI 4.6-6.0) in the placebo group (p<0.0001). One-year survival rates were also higher with trifluridine/tipiracil than placebo (26.6% vs 17.6%).
The most common adverse effects of trifluridine/tipiracil that resulted in treatment discontinuation or dose reduction, interruption or delay included neutropenia, anaemia, fatigue, diarrhoea and dyspnoea.