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Poster display session

4224 - Predictive value of primary tumor location: Results from randomized phase II study of panitumumab + irinotecan versus cetuximab + irinotecan in patients with KRAS exon2 wild-type metastatic colorectal cancer (WJOG6510G)


09 Sep 2017


Poster display session


Cytotoxic Therapy;  Colon and Rectal Cancer


Takao Tamura


Annals of Oncology (2017) 28 (suppl_5): v158-v208. 10.1093/annonc/mdx393


T. Tamura1, D. Sakai2, N. Sugimoto3, S. Tokunaga4, A. Tsuji5, H. Ishida6, S. Otsu7, T. Moriwaki8, H. Satake9, K. Uchino10, S. Matsumoto11, E. Baba12, M. Sato13, H. Taniguchi14, J. Kishimoto15, N. Boku16, I. Hyodo8, K. Muro14

Author affiliations

  • 1 Medical Oncology, Kindai University Faculty of Medicine, 589-8511 - Osaka/JP
  • 2 Department Of Frontier Science For Cancer And Chemotherapy, Osaka University Graduate School of Medicine, 565-0871 - Suita/JP
  • 3 Department Of Medical Oncology, Osaka International Cancer Institute, 541-8567 - Osaka/JP
  • 4 Department Of Clinical Oncology, Osaka City General Hospital, Osaka/JP
  • 5 Department Of Clinical Oncology Faculty Of Medicine, Kagawa University, 761-0793 - Kita-gun/JP
  • 6 Department Of Gastroenterology, Mito Medical Center, Higashi Ibaraki-gun/JP
  • 7 Department Of Medical Oncology And Hematology, Oita University Faculty of Medicine, Oita/JP
  • 8 Faculty Of Medicine, Division Of Gastroenterology, University of Tsukuba, 305-8577 - Tsukuba/JP
  • 9 Department Of Medical Oncology, Kobe City Medical Center General Hospital, Kobe/JP
  • 10 Department Of Medical Oncology, Kyushu Medical Center, Fukuoka/JP
  • 11 Therapeutic Oncology, Kyoto University-Graduate school of medicine, 606-8507 - Kyoto/JP
  • 12 Kyushu University Faculty Of Medical Sciences, Department of Comprehensive Clinical Oncology, Fukuoka/JP
  • 13 Department Of Gastroenterology And Hepatology, Ryugasaki Saiseikai Hopital, Ryugasaki/JP
  • 14 Department Of Clinical Oncology, Aichi Cancer Center Hospital, 464-8681 - Nagoya/JP
  • 15 Department Of Research And Development Of Next Generation Medicine Faculty Of Medical Sciences, Kyushu University, Fukuoka/JP
  • 16 Division Of Gastrointestinal Medical Oncology, National Cancer Center Hospital, 104-0045 - Tokyo/JP


Abstract 4224


WJOG6510G study compared cetuximab (Cmab) versus panitumumab (Pmab) in combination with irinotecan (IRI) for patients (pts) with KRAS exon2 wild-type (WT) metastatic colorectal cancer (mCRC) previously treated with fluoropyrimidine-, oxaliplation- and IRI- based chemotherapies. The study demonstrated that Pmab + IRI was not only non-inferior but slightly superior to Cmab + IRI in terms of PFS and OS (median PFS 4.3 months versus 5.4 months, HR 0.68, 95%CI 0.47-0.99, p = 0.040; median OS 11.5 months versus 14.9 months, HR 0.68, 95% CI 0.46-1.02, p = 0.06) (Sugimoto N, et al. ASCO-GI 2017). Here, we report predefined subgroup analyses of the study according to patient characteristics.


Pre-planned subgroup analyses investigated the homogeneity of treatment effects for PFS and OS across the following subgroups defined by age, gender, ECOG PS, histological type, prior resection of primary site, prior bevacizumab use, reason for oxaliplatin discontinuation, and primary tumor location. Cecum to transverse colon classified as right-sided CRC (RCRC), splenic flexure to rectum classified as left-sided CRC (LCRC).


Totally, 120 (Cmab arm 59, Pmab arm 61) pts were eligible for the analyses. The subgroup analyses in PFS and OS revealed favorable tendency of Pmab arm for almost all factors. Among patients with LCRC (n = 104), Pmab+IRI significantly improved PFS and OS relative to Cmab+IRI (median PFS 4.2 months versus 5.6 months, HR 0.65, 95% CI 0.44-0.97, p = 0.030; median OS 11.1 months versus 15.4 months, HR 0.62, 95% CI 0.40-0.96, p = 0.030). In contrast, in RCRC tumors, comparable survival outcomes were observed between Cmab arm and Pmab arm.


Pmab + IRI for pretreated mCRC patients was associated with favorable PFS and OS compared to Cmab + IRI, especially with left-sided colorectal tumors.

Clinical trial identification


Legal entity responsible for the study

West Japan Oncology Group (WJOG)




A. Tsuji: Honoraria: Daiichi Sankyo, Taiho Pharmaceutical, Chugai Pharma, Merck Serono, Takeda Pharmaceutical, Bristol-Myers Squibb Japan. Speakers\' Bureau: Chugai Pharma, Taiho Pharmaceutical, Takeda, Merck Serono. T. Moriwaki: Corporate-sponsored research: Taiho, Chugai, Takeda, Boelinger Ingelheim, Sanofi-Aventis, and Yakult Honsha. H. Satake: Honoraria from Bayer, Chugai Pharma, Eli Lilly Japan, Merck Serono, Takeda, Taiho Pharmaceutical, and Yakult Honsha. E. Baba: Speakers\' Bureau: Chugai Pharm, Eli Lilly. H. Taniguchi: Honoraria for speaking from Takeda and Merck Serono. Research funding from Takeda. I. Hyodo: Honoraria from Taiichi-Sankyo, Chugai, and Taiho Pharmaceutical Companies. All other authors have declared no conflicts of interest.

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