P-245 - Cetuximab with infusional or oral fluorouracil in 1st line treatment for metastatic colorectal cancer: a comparison study

Date 04 July 2015
Event WorldGI 2015
Session Posters
Topics Anti-Cancer Agents & Biologic Therapy
Colon Cancer
Rectal Cancer
Presenter M. Kotaka
Citation Annals of Oncology (2015) 26 (suppl_4): 1-100. 10.1093/annonc/mdv233
Authors M. Kotaka1, H. Satake2, A. Tsuji2, T. Kotake2, Y. Okita2, Y. Hatachi2
  • 1Sano Hospital, Kobe-shi/JP
  • 2Kobe City Medical Center General Hospital, Kobe/JP

Abstract

Introduction

In RAS wild-type colorectal cancer, the anti-EGFR monoclonal antibody cetuximab has shown activity in various therapeutic settings, and has been successfully combined with different conventional chemotherapy regimens in randomized trials, including irinotecan- and oxaliplatin-based regimens. Subgroup analysis of the MRC COIN trial showed that cetuximab had a detrimental effect on combination with oral fluoropyrimidine (FU), capecitabine and oxaliplatin and the use of cetuximab in combination with capecitabine and oxaliplatin is accordingly not recommended. Furthermore, an infusional FU regimen is regarded as a more optimal backbone for the addition of cetuximab. S-1 is a new oral anticancer drug that combines tegafur, a prodrug of fluorouracil, with 5-chloro-2,4-dihydropyrimidine (CDHP), and potassium oxonate in a molar ration of 1:0.4:1. S-1 has shown an anti-cancer effect on combination with oxaliplatin (SOX regimen) or irinotecan (IRIS regimen) for colorectal cancer. Here, we evaluated the efficacy and safety of cetuximab in combination with oral FU-based regimens compared with infusional FU-based regimens.

Methods

From July 2011 to June 2013, 33 patients with metastatic colorectal cancer were given 1st line treatment with cetuximab in combination with cytotoxic regimens at two tertiary referral hospitals. Selection criteria were 1st line systemic chemotherapy for metastatic colorectal adenocarcinoma and KRAS exon 2 wild type. Long-term survival, safety and clinical outcomes were retrospectively evaluated. Results of the infusional and oral FU regimen groups were compared.

Results

Among 33 patients, 9 received infusional FU and the other 24 received oral FU, of whom 23 received oral S-1 and 1 received capecitabine. Thirty-one patients received an oxaliplatin-based regimen and two received an irinotecan-based regimen. With a median follow up of 16 months, median overall survival was significantly longer in the infusional FU group (not reached) than the oral FU group (21.4 months (95% confidence interval (CI) 12.7-30.0; p = 0.031). Progression-free survival did not statistically differ (13.4 months (95%CI 6.2-20.7) vs 8.0 months (95%CI 6.1-9.9), respectively; p = 0.087).

Conclusion

An S-1-based regimen showed inferior survival to infusional FU, as did capecitabine. Cetuximab combined with oral FU as an S-1-based regimen cannot be recommended for the treatment of metastatic colorectal cancer.