S-1 plus oxaliplatin versus capecitabine plus oxaliplatin for first-line treatment of patients with metastatic colorectal cancer: a randomised, non-inferiority phase 3 trial.
BACKGROUND
Capecitabine plus oxaliplatin (CapeOX) is one of the reference doublet cytotoxic chemotherapy treatments for patients with metastatic colorectal cancer. We aimed to compare the efficacy and safety of CapeOX with that of S-1 plus oxaliplatin (SOX), a promising alternative treatment for patients with metastatic colorectal cancer.


METHODS
In this open-label, multicentre, randomised phase 3 trial, we randomly assigned patients (1:1) from 11 institutions in South Korea to receive either CapeOX (capecitabine 1000 mg/m(2) twice daily on days 1-14 and oxaliplatin 130 mg/m(2) on day 1) or SOX (S-1 40 mg/m(2) twice daily on days 1-14 and oxaliplatin 130 mg/m(2) on day 1). Treatment was repeated every 3 weeks and continued for as many as nine cycles of oxaliplatin-containing chemotherapy, except in instances of disease progression, unacceptable toxicity, or a patient's refusal. Maintenance chemotherapy with S-1 or capecitabine was allowed after discontinuation of oxaliplatin. Randomisation was done with a computer-generated sequence (stratified by primary sites, previous adjuvant or neoadjuvant treatment, and the presence of measurable lesions). The primary endpoint was to show non-inferiority of SOX relative to CapeOX in terms of progression-free survival (PFS). The primary analysis was by intention to treat. This study is registered with ClinicalTrials.gov, number NCT00677443.


RESULTS
Between May 14, 2008, and Sept 23, 2009, we randomly assigned 168 patients to receive SOX and 172 to receive CapeOX. Median PFS was 8·5 months (95% CI 7·6-9·3) in the SOX group and 6·7 months (6·2-7·1) in the CapeOX group (hazard ratio, 0·79 [95% CI 0·60-1·04]; p(non-inferiority)<0·0001, p(log-rank)=0·09). The upper limit of the CI was below the predefined margin of 1·43, showing the non-inferiority of SOX to CapeOX. We recorded a higher incidence of grade 3-4 neutropenia (49 [29%] vs 24 [15%]), thrombocytopenia (37 [22%] vs 11 [7%]), and diarrhoea (16 [10%] vs seven [4%]) in the SOX group than in the CapeOX group. The frequency of any grade of hand-foot syndrome was greater in the CapeOX group than it was in the SOX group (51 [31%] vs 23 [14%]).


CONCLUSIONS
The SOX regimen could be an alternative first-line doublet chemotherapy strategy for patients with metastatic colorectal cancer. Further investigation is needed to explore its potential when used together with other targeted agents or as adjuvant chemotherapy.


BACKGROUND
Korea Healthcare Technology Research and Development Project, Ministry of Health and Welfare, South Korea.
Department of Oncology, Asan Medical Centre, University of Ulsan College of Medicine, Seoul, South Korea.
Yong Sang
YS
Hong
Young Suk
YS
Park
Ho Yeong
HY
Lim
Jeeyun
J
Lee
Tae Won
TW
Kim
Kyu-pyo
KP
Kim
Sun Young
SY
Kim
Ji Yeon
JY
Baek
Jee Hyun
JH
Kim
Keun-Wook
KW
Lee
Ik-Joo
IJ
Chung
Sang-Hee
SH
Cho
Kyung Hee
KH
Lee
Sang Joon
SJ
Shin
Hye Jin
HJ
Kang
Dong Bok
DB
Shin
Sook Jung
SJ
Jo
Jae Won
JW
Lee
D000368:Aged; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000008:administration & dosage / Q000009:adverse effects; D000069287:Capecitabine; D015179:Colorectal Neoplasms / Q000188:drug therapy* / Q000473:pathology / Q000556:secondary; D003841:Deoxycytidine / Q000008:administration & dosage / Q000009:adverse effects / Q000031:analogs & derivatives*; D018572:Disease-Free Survival; D004338:Drug Combinations; D005260:Female; D005472:Fluorouracil / Q000008:administration & dosage / Q000009:adverse effects / Q000031:analogs & derivatives*; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D009944:Organoplatinum Compounds / Q000008:administration & dosage / Q000009:adverse effects; D000077150:Oxaliplatin; D010094:Oxonic Acid / Q000008:administration & dosage / Q000009:adverse effects; D056910:Republic of Korea; D005641:Tegafur / Q000008:administration & dosage / Q000009:adverse effects
D004338:Drug Combinations; D009944:Organoplatinum Compounds; D000077150:Oxaliplatin; D003841:Deoxycytidine; C079198:S 1 (combination); D005641:Tegafur; D010094:Oxonic Acid; D000069287:Capecitabine; D005472:Fluorouracil