198P - Molecular biomarker study in randomized phase II trial of capecitabine plus cisplatin versus S-1 plus cisplatin as a first-line treatment for advan...

Date 19 December 2015
Event ESMO Asia 2015 Congress
Session Poster presentation 1
Topics Anti-Cancer Agents & Biologic Therapy
Gastric Cancer
Translational Research
Presenter Akira Tsuburaya
Citation Annals of Oncology (2015) 26 (suppl_9): 42-70. 10.1093/annonc/mdv523
Authors A. Tsuburaya1, K. Nishikawa2, M. Kobayashi3, J. Kawada4, T. Namikawa3, R. Fukushima5, H. Kojima6, K. Tanabe7, K. Yamaguchi8, S. Yoshino9, M. Takahashi10, N. Hirabayashi11, S. Sato12, H. Nemoto13, Y. Rino14, T. Yoshikawa15, J. Nakajima16, P. Tan17, S. Morita18, J. Sakamoto19
  • 1Gastroenterological Center, Yokohama City University Medical Center, 2320024 - Yokohama/JP
  • 2Surgery, National Hospital Organization Osaka National Hospital, 540-0006 - Osaka/JP
  • 3Human Health And Medical Sciences, Kochi Medical School Hospital, Nangoku/JP
  • 4Surgery, Osaka General Medical Center, Osaka/JP
  • 5Surgery, Teikyo University, Tokyo/JP
  • 6Gastroenterological Surgery, Aichi Cancer Center - Aichi Hospital, Okazaki/JP
  • 7Gastroenterological And Transplant Surgery, Hiroshima University, Hiroshima/JP
  • 8Surgical Oncology, Gifu University, Graduate School of Medicine, 5011194 - Gifu/JP
  • 9Department Of Digestive Surgery And Surgical Oncol, Yamaguchi University Graduate School of Medicine, 755-8505 - Ube/JP
  • 10Surgery, Yokohama Municipal Citizen's Hospital, Yokohama/JP
  • 11Surgery, Hiroshima City Asa Hospital, 731-0223 - Hiroshima/JP
  • 12Gastroenterological Surgery, Saga-Ken Medical Center Koseikan, Saga/JP
  • 13Gastroenterological And General Surgery, Showa University Fujigaoka Hospital, Yokohama/JP
  • 14Surgery, Yokohama City University, Yokohama/JP
  • 15Gastrointestinal Surgery, Kanagawa Cancer Center, Yokohama/JP
  • 16Surgery, Obihiro Kousei Hospital JA Hokkaidoukouseiren, Obihiro/JP
  • 17Cancer And Stem Cell Biology, Duke-NUS Graduate Medical School Singapore, Singapore/SG
  • 18Biomedical Statistics And Bioinformatics, Kyoto University-Graduate school of medicine, Kyoto/JP
  • 19Hospital Director, Tokai Central Hospital, Kakamigahara/JP

Abstract

Aim/Background

Among standard chemotherapy regimens for advanced gastric cancer; capecitabine plus cisplatin (XP) and S-1 plus cisplatin (SP) were comparable in a multicenter randomized phase II trial, XParTS II. This study was designed to identify molecular biomarkers for XP and SP in the trial.

Methods

Paraffin-embedded primary tumor specimens were collected in 98 of 116 randomized patients in XParTS II. The mRNA was measured with a real-time PCR for thymidine phosphorylase (TP), dihydropyrimidine dehydrogenase (DPD), orotate phosphoribosyltransferase (OPRT), and thymidylate synthase (TS), and categorized at median into low or high subgroups in order to analyze their association with efficacy endpoints.

Results

Baseline demographic and clinical characteristics of the subjects were similar to the results of the original trial. There was no significant difference in each marker between XP and SP groups; while TP was higher in samples from patients with measurable lesions, and TS was higher in patients with intestinal type and measurable tumors. In comparison for efficacy between XP and SP groups, there was no interaction for PFS and TTF for each marker. While for OS, OPRT was associated with efficacy of the treatment regimens; for XP vs. SP, hazard ratios were 2.0 and 0.73 for low and high mRNA, respectively (P = 0.098 for interaction).

Conclusions

OPRT is suggested to be a candidate predictive biomarker for the first-line treatment of advanced gastric cancer by XP or SP. Further examination is warranted to confirm these results in other clinical trials and/or cohort studies.

Clinical trial identification

NCT0140624

Disclosure

All authors have declared no conflicts of interest.