189P - Phase II trial of S-1 plus panitumumab for wild-type KRAS unresectable colorectal cancer patients previously treated with 5-fluorouracil (5-FU), ox...

Date 17 December 2016
Event ESMO Asia 2016 Congress
Session Poster lunch
Topics Anticancer Agents
Colon and Rectal Cancer
Rectal Cancer
Presenter Yasuo Sakamoto
Citation Annals of Oncology (2016) 27 (suppl_9): ix53-ix67. 10.1093/annonc/mdw581
Authors Y. Sakamoto1, Y. Yoshida2, H. Ishikawa3, T. Ohchi4, H. Takeshita5, Y. Emi6, H. Komatsu7, T. Sawai8, T. Shimose9, E. Oki10, H. Saeki11, Y. Kakeji12, Y. Yoshida13, H. Baba14, Y. Maehara10
  • 1Deapartment Of Gastroenterological Surgery, Kumamoto University, 860-8556 - Kumamoto/JP
  • 2Gastroenterological Surgery, Fukuoka University Faculty of Medicine, 814-0180 - Fukuoka/JP
  • 3Gastorointestinal Surgery, Sasebo City General Hospital, 857-8511 - Nagasaki/JP
  • 4Surgery, Kurume University School of Medicine, 830-0011 - Kurume/JP
  • 5Surgical Oncology, Nagaski University Hospital, 852-8501 - Nagasaki/JP
  • 6Surgery, Saiseikai Fukuoka General Hospital, 810-0001 - Fukuoka/JP
  • 7Surgery, Japan Community Health care Organization Isahaya General Hospital, 854- - Isahaya/JP
  • 8Division Of Nursing, Nagasaki University School of Health Sciences, 852-8520 - Nagasaki/JP
  • 9Gastorointestinal Surgery, Clinical Research Support Center Kyushu, 812-8582 - Fukuoka/JP
  • 10Gastroenterological Surgery, Kyushu University Hospital, 812-8582 - Fukuoka/JP
  • 11Graduate School Of Medical Sciences, Kyushu University Hospital, 812-8582 - Fukuoka/JP
  • 12Surgery And Science, Graduate School Of Medical Sciences, Kyushu University Hospital, 812-8582 - Fukuoka/JP
  • 13Gastroenterological Surgery, Kurume University, 830-0011 - Kurume/JP
  • 14Gastroenterological Surgery, Kumamoto University, 860-8556 - Kumamoto/JP



Anti-epidermal growth factor receptor antibody is been a promising third-line regimen for wild-type RAS patients who have already treated with oxaliplatin- and irinotecan-based regimens. The purpose of this phase II study is to explore the efficacy and safety of S-1 plus panitumumab for the wild-type KRAS unresectable colorectal cancer patients who have been previously treated with key drugs for colorectal cancer, such as 5-FU, oxaliplatin and irinotecan.


Wild-type KRAS unresectable colorectal cancer patients who were treated by key drugs were enrolled in this study. They protocol regimen consisting of oral S-1 40-80 mg twice daily was administered on days 1 to 28 every 6 weeks followed by a 2-week rest period plus intravenous panitumumab 6 mg/m2 every 2 weeks until disease progression. The primary endpoint was progression-free survival.


Of the thirty-two patients enrolled in this study, twenty-eight patients were analyzed for efficacy, because four patients had to be excluded due to their short washout period. The most frequent hematological adverse event was anemia (any grade: 81.3%, grade 3/4: 9.4%). Other common severe adverse events (Grade 3/4) were skin rash (31.3%), anorexia (18.8%) and diarrhea (9.4%). Response rate and disease-control rate were 17.9% (95% confidential interval: 6.1-36.9%) and 50.0% (95% C.I.: 30.7-69.4%), respectively. Six-month and 1-year progression-free survival (PFS) rates were 25.9% (90% C.I.: 13.4-40.3%) and 7.4% (90% C.I.: 1.8-18.4%), respectively. Median PFS time was 4.0 months (90% C.I.: 2.76-5.42 months). The one-year overall survival (OS) rate was 47.6% (95% C.I.: 28.1-64.9%). Median survival time was 11.9 months.


This trial couldn’t show the efficacy of S-1 plus panitumumab since the lower limit of median PFS lowered than threshold. While a small number of pts indicate that this conclusion be viewed with caution, S-1 plus panitumumab induced high incidence of Grade 3 skin rash. Serious drug interaction between S-1 and panitumumab might increase the risk of skin toxicity.

Clinical trial indentification


Legal entity responsible for the study



Kyushu Study group of Clinical Cancer


All authors have declared no conflicts of interest.