Updated results of the GEST study: Randomized phase III study of gemcitabine plus S-1 (GS) versus S-1 versus gemcitabine (GEM) in unresectable advanced pancreatic cancer in Japan and Taiwan.

Gastrointestinal (Noncolorectal) Cancer
Session Type and Session Title: 
General Poster Session, Gastrointestinal (Noncolorectal) Cancer
Abstract Number: 


J Clin Oncol 30, 2012 (suppl; abstr 4035)
Akira Fukutomi, Takuji Okusaka, Kazuya Sugimori, Hideki Ueno, Tatsuya Ioka, Shinichi Ohkawa, Narikazu Boku, Kenji Yamao, Kazuhiro Mizumoto, Junji Furuse, Akihiro Funakoshi, Takashi Hatori, Taketo Yamaguchi, Shinichi Egawa, Atsushi Sato, Yasuo Ohashi, Ann-Lii Cheng, Masao Tanaka; Shizuoka Cancer Center, Sunto-gun, Japan; National Cancer Center Hospital, Tokyo, Japan; Yokohama City University Medical Center, Yokohama, Japan; Osaka Medical Center for Cancer and Cardiovascular Diseases, Osaka, Japan; Kanagawa Cancer Center Hospital, Yokohama, Japan; Aichi Cancer Center Hospital, Nagoya, Japan; Kyushu University, Fukuoka, Japan; Kyorin University School of Medicine, Tokyo, Japan; Fukuoka Sanno Hospital, Fukuoka, Japan; Tokyo Women's Medical University, Tokyo, Japan; Chiba Cancer Center, Chiba, Japan; Tohoku University Graduate School of Medicine, Sendai, Japan; Showa University Hospital, Tokyo, Japan; The University of Tokyo, Tokyo, Japan; National Taiwan University Hospital, Taipei, Taiwan

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Abstract Disclosures


Background: The GEST study (Ioka et al. ASCO 2011, Abstract 4007) demonstrated the non-inferiority of S-1 to GEM with respect to the primary endpoint of overall survival (OS) in patients with pancreatic cancer (PC). We now report the updated results of this study. Methods: The GEST study was a randomized, 3-arm, phase III study. Chemotherapy-naive patients with unresectable advanced PC, an ECOG Performance status (PS) of 0-1, and adequate organ functions were randomly assigned to receive GEM (1000 mg/m2, iv, d1, 8 and 15, q4w), S-1 (80/100/120 mg/day based on BSA, po, d1-28, q6w), or GS (GEM 1000 mg/m2, iv, d1 and 8 plus S-1 60/80/100 mg/day based on BSA po, d1-14, q3w). The primary endpoint was OS, used to assess the non-inferiority of S-1 and the superiority of GS to GEM. Patient information was updated in July 2011. Results: At the time of this follow-up analysis, median follow-up was 29.8 months with 795 OS events, compared with 18.4 months with 710 OS events out of 832 patients at the previous analysis. Median OS was 8.8 months (95% CI: 8.0–9.7) in the GEM group and 9.7 months (95% CI: 7.6-10.8) in the S-1 group (HR=0.96, 97.5% CI: 0.79-1.17, p<0.001 for non-inferiority), which is consistent with prior results (HR=0.96, 97.5% CI: 0.78-1.18, p<0.001). In the GS group, median OS was 9.9 months (95% CI: 9.0-11.2). The HR was 0.91 (97.5%CI: 0.75-1.11, p=0.28 for superiority versus the GEM group). On subgroup analysis, GS was associated with a non-statistically significant trend toward better OS compared with GEM among patients with locally advanced disease and those with a PS of 1. Median OS was 12.7 months (95% CI: 9.7–14.9) in the GEM group and 15.9 months (95% CI: 13.0-19.7) in the GS group (HR=0.72, 95% CI: 0.51-1.03) among patients with locally advanced disease, and 6.2 months (95% CI: 4.9–8.3) in the GEM group and 9.6 months (95% CI: 8.0-10.9) in the GS group (HR=0.62, 95% CI: 0.46-0.83) among patients with a PS of 1. Conclusions: The non-inferiority of S-1 to Gem in terms of the primary endpoint of OS was reconfirmed. Monotherapy with S-1 can be used as one of the standard treatments for advanced PC. As for GS therapy, there is room for further investigation.