S1 to supplant Gemcitabine in resected PCA?

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Keepin' it real yo
10+ Year Member
Nov 28, 2005
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Just presented at the ASCO GI Symposium:

Background: Gemcitabine (GEM) has been a standard treatment of adjuvant chemotherapy for resected pancreatic cancer (PC). S-1 is an oral fluoropyrimidine, and shown to be non-inferior to GEM on overall survival (OS) for unresectable PC. The aim of this study is to determine non-inferiority of S-1 to GEM on OS as an adjuvant chemotherapy for resected PC. Methods: Patients (pts), who met the following criteria; histologically confirmed ductal adenocarcinoma of the pancreas, R0 or R1 resection, pathological stage I, II, or III with resection of the celiac axis, age >20, no prior chemotherapy or radiotherapy within 3 years, and adequate organ functions, were randomly assigned to GEM (1000 mg/m2, div on days 1, 8 and 15, repeated every 4 weeks, for 6 courses) or S-1 (40-60 mg according to the body surface, twice a day, for 4 weeks, repeated every 6 weeks, for 4 courses). Primary endpoint was OS. With 180 pts in each, the study had 80% power to prove non-inferiority with a non-inferiority margin of hazard ratio (HR) 1.25 on the basis of expected HR 0.87, at 0.05 two-sided alpha. An interim analysis was planned after 180 deaths. Results: From 4/2007 to 6/2010, 385 pts were enrolled (GEM: 193, S-1: 192) from 33 hospitals in Japan. In 378 pts (GEM: 191, S-1:187) of the full analysis set, background factors were well balanced between groups. Based on the interim analysis on survival data obtained by 7/2012, the independent data monitoring committee recommended to publish the results soon. The HR for S-1 to GEM was 0.56 (95% CI, 0.42-0.74, p<0.0001 for non-inferiority, p<0.0001 for superiority). The 2-year survival rates were 53% (95% CI, 46-60) for GEM and 70% (63-76) for S-1. The reasons for treatment discontinuation (recurrence/toxicity/patient’s refusal/others) were 27/48/5/2 in GEM and 9/40/3/0 in S-1. Incidences (%) of grade 3/4 toxicities in GEM/S-1 were fatigue (4.7/5.4), anorexia (5.8/8.0), leukopenia (38.7/8.6), thrombocytopenia (9.4/4.3), anemia (17.3/13.4), and elevated AST (5.2/1.1). Conclusions: S-1 adjuvant chemotherapy is shown non-inferior, and furthermore, even superior to GEM. S-1 may be considered as the new standard treatment for resected PC pts. Clinical trial information: UMIN000000655.