587PThe impact of late-line treatment on overall survival (OS) from the initiation of first-line chemotherapy (CT) for patients (pts) with metastatic colorectal cancer (mCRC)

Abstract Background For the past 20 years, the improvement in OS has been achieved in mCRC. Active agents including anti-VEGF and anti-EGFR antibodies have contributed to this progress. Late-line treatment with regorafenib (REGO) or trifluridine/tipiracil (FTD/TPI) has also been demonstrated to be effective and these drugs are widely used as standard CT. However, no study has reported to what extent the availability of these two drugs changes the total OS of patients that is measured from the initiation of first-line CT. Methods We retrospectively enrolled consecutive mCRC pts at 3 institutions who received first-line CT between Jan 2005 and Sep 2016. We divided the pts into 3 groups according to the availability of drugs at the initiation of first-line CT; pts who started CT between Jan 2005 and Dec 2006 (cohort A: only cytotoxic drugs were available), between Jan 2007 and Dec 2011 (cohort B: anti-VEGF and anti-EGFR antibody were available), or between Jan 2012 and Sep 2016 (cohort C: REGO and FTD/TPI were available). Treatment outcomes were compared among the cohort A, B, and C. Results A total of 1,426 pts were analyzed. Pts characteristics of the cohort A (165 pts), B (626 pts), and C (635 pts) were as follows: median age, 62/64/65 years; ECOG PS ≥ 2, 8.5%/8.8%/8.2%; right-sided primary, 26.1%/29.4%/29.9%; tumor grade Grade 3, 10.1%/13.1%/11.9%; KRAS mutation, 28.6%/38.4%/41.1%; and number of metastatic sites ≥2, 63.6%/61.3%/58.1%. In the cohort A, B, and C, 1.2%, 10.7%, and 31.2% of the pts received at least one of late-line treatment with REGO or FTD/TPI. Median OS of the cohort A, B, and C was 18.6 month (M), 25.3 M, and 27.2 M. Hazard ratio (HR) of death was 0.82 (95% confidential interval [CI], 0.68-0.98; p = 0.0309) for the cohort B vs A, and 0.71 (95% CI, 0.59-0.86; p = 0.0004) for the cohort C vs A, and 0.87 (95% CI 0.77-0.99; p = 0.0356) for the cohort C vs B. Conclusions This real-world data analysis indicates that late-line treatment with REGO or FTD/TPI could contribute to the prolongation of OS from the initiation of first-line CT for mCRC pts. Legal entity responsible for the study The authors. Funding Has not received any funding. Disclosure T. Masuishi: Honoraria (self): Taiho Pharmaceutical, Merck Serono, Chugai Pharma, Yakult Honsha, Takeda, Eli Lilly, Bayer Yakuhin, Sanofi; Research grant / Funding (self): Yakult Honsha. Y. Kawamoto: Honoraria (self): Taiho Pharmaceutical, Daiichi Sankyo, Takeda Pharmaceutical, Chugai Pharmaceutical, Merck Biopharma, Eli Lilly. S. Yuki: Honoraria (self): Chugai Pharmaceutical Co., Ltd., Takeda Pharmaceutical Co., Ltd., Bristol-Myers Squibb Co., Ltd., Eli Lilly Japan K.K., Bayer Yakuhin Co., Ltd., Taiho Pharmaceutical Co., Ltd., Ono Pharmaceutical Co., Ltd., Sanofi K.K., Pharma International Inc., Yakult H. Y. Komatsu: Honoraria (self): Taiho, Chugai, Yakult, Daiichi Sankyo, Bayer, Merck, Takeda; Research grant / Funding (institution): Taiho, Chugai, Yakult, Daiichi Sankyo, Bayer, Merck, Takeda. K. Muro: Honoraria (self): Takeda, Chugai Pharma, Yakult Honsha, Merck Serono, Taiho Pharmaceutical, Lilly, Ono Pharmaceutical, Bayer; Research grant / Funding (self): Ono Pharmaceutical, MSD, Daiichi Sankyo, Shionogi, Kyowa Hakko Kirin, Gilead Sciences, Merck Serono, Pfizer, Sanofi. T. Yamanaka: Honoraria (self): Chugai, Takeda, Taiho, Boehringer-Ingelheim, Bayer, Pfizer; Advisory / Consultancy: Gilead Sciences, Daiichi-Sankyo, Sysmex, Huya Biosciences; Honoraria (institution): Chugai, Takeda, Taiho, Boehringer-Ingelheim, Bayer, Daiichi-Sankyo, Ono, Merck Serono, Astellas, Eli Lilly. K. Yamazaki: Honoraria (self): Chugai Pharma, Daiichi Sankyo, Yakult Honsha, Takeda, Bayer, Merck Serono, Bristol-Myers Squibb Japan, Taiho Pharmceutical, Lilly, Sanofi, Ono Pharmaceutical, MSD; Research grant / Funding (institution): Taiho Pharmaceutical. All other authors have declared no conflicts of interest.