Original Study Safety and Efficacy of Trifluridine/Tipiracil Monotherapy in Clinical Practice for Patients With Metastatic Colorectal Cancer: Experience at a Single Institution Daisuke Kotani, 1 Kohei Shitara, 1 Akihito Kawazoe, 1 Shota Fukuoka, 1 Yasutoshi Kuboki, 1 Hideaki Bando, 1 Wataru Okamoto, 1 Takashi Kojima, 1 Toshihiko Doi, 1 Atsushi Ohtsu, 2 Takayuki Yoshino 1 Abstract Little information is available regarding the safety and efficacy of trifluridine/tipiracil (TAS-102) monotherapy in clinical practice. A retrospective study of 55 patients at a single institution was performed to clarify the safety and efficacy of TAS-102 monotherapy in clinical practice. Our findings indicate that the safety and efficacy of TAS-102 seen in pivotal trials are maintained in clinical practice, regardless of the previous use of regorafenib. Background: The combination drug TAS-102 is a novel oral nucleoside antitumor agent containing trifluridine and tipiracil hydrochloride, which prevents the degradation of trifluridine. The global phase III RECOURSE trial (Study of TAS- 102 in Patients With Metastatic Colorectal Cancer Refractory to Standard Chemotherapies) demonstrated that TAS-102 prolonged the survival of patients with metastatic colorectal cancer (mCRC) whose disease progressed after standard therapies. TAS-102 was first approved in Japan in March 2014, and little is known about its safety and efficacy in clinical practice, especially for mCRC patients with previous regorafenib treatment. Patients and Methods: We investigated the safety and efficacy of TAS-102 monotherapy in clinical practice for patients with mCRC refractory to standard therapies who were treated from May 2014 to January 2015. Results: A total of 55 patients received TAS-102. The Eastern Cooperative Oncology Group performance status was 0, 1, and 2 in 41.8%, 47.3%, and 10.9% of patients. Of the 55 patients, 32 (58.2%) had been treated with regorafenib before receiving TAS-102. The median progression-free survival and overall survival was 2.0 months and 5.3 months, respectively. Emergency hospitalization was required for 23.6% of the patients during TAS-102 treatment, although most of the events (76.9%) were disease-related. The most common grade 3 or 4 adverse events were neutropenia (41.8%), leukopenia (27.2%), anemia (23.6%), febrile neutropenia (5.5%), and fatigue (3.6%). The frequency of grade  3 events was not significantly increased among the patients who had compared with those who had not received regorafenib. The progression-free survival (median 2.1 vs. 2.0 months) and overall survival (median 6.2 vs. 4.7 months) were similar for the 2 subgroups. Conclusion: The safety and efficacy of TAS-102 monotherapy in clinical practice were maintained, irrespective of previous regorafenib treatment. Clinical Colorectal Cancer, Vol. -, No. -, --- ª 2015 Elsevier Inc. All rights reserved. Keywords: ECOG PS, Novel oral nucleoside, Salvage line chemotherapy, TAS-102, With and without previous Regorafenib Introduction Colorectal cancer is the third most common cancer and the fourth leading cause of cancer death worldwide. 1 The development of combination chemotherapy regimens with cytotoxic drugs (eg, oxa- liplatin, irinotecan, and fluoropyrimidine) and molecular targeting agents (eg, bevacizumab, aflibercept, cetuximab, panitumumab, and 1 Department of Gastrointestinal Oncology, National Cancer Center Hospital East, Kashiwa, Chiba, Japan 2 Exploratory Oncology Research and Clinical Trial Center, National Cancer Center, Kashiwa, Chiba, Japan Submitted: Aug 27, 2015; Revised: Oct 23, 2015; Accepted: Nov 23, 2015 Address for correspondence: Kohei Shitara, MD, Department of Gastrointestinal Oncology, National Cancer Center Hospital East, 6-5-1 Kashiwanoha, Kashiwa, Chiba 277-8577, Japan E-mail contact: kouheis0824@yahoo.co.jp 1533-0028/$ - see frontmatter ª 2015 Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.clcc.2015.11.005 Clinical Colorectal Cancer Month 2015 - 1