Author Manuscript Published OnlineFirst on April 28, 2016; DOI: 10.1158/1078-0432.CCR-15-2783 Author manuscripts have been peer reviewed and accepted for publication but have not yet been edited. TAS-102 for Treatment of Advanced Colorectal Cancers that Are No Longer Responding to Other Therapies Daphne L. van der Velden1, Frans L. Opdam2, and Emile E. Voest1 1 The Netherlands Cancer Institute - Antoni van Leeuwenhoek Hospital, Department of Molecular Oncology, Amsterdam, the Netherlands 2 The Netherlands Cancer Institute - Antoni van Leeuwenhoek Hospital, Department of Clinical Pharmacology, Amsterdam, the Netherlands Corresponding Author: Frans L. Opdam, Division of Medical Oncology, The Netherlands Cancer Institute - Antoni van Leeuwenhoek Hospital, Postbus 90203, 1006 BE Amsterdam, the Netherlands. E-mail:
[email protected] Running Title: TAS-102 for Treatment of Advanced Colorectal Cancer Disclosure of Potential Conflicts of Interest No potential conflicts of interest were disclosed. Abstract TAS-102 is a novel oral formulation of trifluridine (TFT) and tipiracil hydrochloride (TPI), a thymidine phosphorylase inhibitor. TFT was originally synthesized in the 1960s and is a nucleoside analog that impedes DNA synthesis by inhibition of thymidylate synthase. TFT’s main mechanism of action however seems to be its incorporation into DNA, which distinguishes TFT from current well-known antimetabolites like 5-fluorouracil (5-FU). The rapid degradation of TFT brought initial clinical development to a halt, but TFT re-entered clinical trials when addition of a TPI was found to improve the bio-availability of TFT. The combined TFT-TPI formulation was tested in patients with treatment- refractory metastatic colorectal cancer in the randomized phase III RECOURSE study.