LAUSR

BACKGROUND The novel oral nucleoside antineoplastic agent trifluridine/tipiracil was approved for metastatic colorectal cancer in Japan in March 2014. In this post-marketing surveillance study, we investigated the safety and efficacy of trifluridine/tipiracil in a real-world setting, particularly haematological drug reactions classified according to the baseline renal and hepatic functions. METHODS We investigated patients with metastatic colorectal cancer who received trifluridine/tipiracil during the first four treatment cycles prospectively. The patients typically received 35 mg/m2 trifluridine/tipiracil twice daily on days 1-5 and 8-12 every 28 days. The primary objective was to assess the safety of trifluridine/tipiracil, but its efficacy was also evaluated. RESULTS Between July 2014 and June 2016, 860 patients were enrolled in the study, and the safety and efficacy of trifluridine/tipiracil were evaluated in 823 patients. Adverse drug reactions occurred in 89.7% of the patients. The most common adverse drug reactions were decreased white blood cell count (67.0%) and neutrophil count (63.9%). Haematological drug reactions of grade ≥3 were observed in 41.7% of the patients with normal renal function; 50.3, 65.6 and 78.9% of the patients had mild, moderate and severe renal impairments, respectively. Hepatic impairment was not associated with a higher incidence of haematological drug reactions. The median overall survival was 8.4 months, with a 1-year survival rate of 33.7%. CONCLUSION This post-marketing surveillance study further confirmed the safety and tolerability profile of trifluridine/tipiracil observed in a clinical study setting.