635P - Randomized Phase Ii Study of Cpt-11 Vs Ptx Vs Each Combination Chemotherapy with S-1 in Patients with Advanced Gastric Cancer Refractory to S-1 or S-1 Plus Cddp (Ogsg0701)

Abstract

ABSTRACT Aim: S-1 plus cisplatin (SP) is recognized as standard first-line chemotherapy for advanced gastric cancer (AGC) and S-1 monotherapy is recognized as standard adjuvant chemotherapy for locally AGC in Japan. Taxane and CPT-11 are two main options and a retrospective analysis has reported that S-1 combination chemotherapy extended overall survival (OS), as second-line chemotherapy for AGC refractory to S1-based chemotherapy. Thus, this prospective multicenter phase II study was carried out to examine efficacy and safety comparing CPT-11, PTX, and each combination chemotherapy with S-1 refractory to S-1 or SP. Methods: Patients with AGC after first-line chemotherapy with S-1 or SP, or during adjuvant chemotherapy or within 26 weeks after adjuvant chemotherapy completion with S-1 who confirmed disease progression by imaging were eligible. Patients were randomly divided into four groups by treatment as follows; Group A: CPT-11 150 mg/m2, day1, q14days, Group B: PTX 80 mg/m2, day1, 8,15, q28days, Group C1: CPT-11 80 mg/m2, day1, 15, S-1 80 mg/m2, day1-21, q35days, Group C2: PTX 50 mg/m2, day1, 8, S-1 80 mg/m2, day1-14, q21days. Primary endpoint was OS, and secondary endpoints were progression-free survival (PFS), response rate and safety. Results: From July 2008 to March 2012, 127 patients were enrolled. Reason for terminating the protocol treatment was for progressive disease(PD) in 86/81/86/76 (Group A/B/C1/C2, %), respectively. Median OS was 11.3/11.3/14.6/10.5 months(M) (Group A/B/C1/C2), 11.8 M in Group A + C1 and 11.1 M in Group B + C2 (p = 0.922, HR: 0.981 [0.679-1.419]), and 11.3 M in Group A + B and 11.1 M in Group C1 + C2 (p = 0.808, HR:0.952 [0.643-1.412]), respectively. Median PFS was 3.0/4.4/3.8/3.5 M (Group A/B/C1/C2), 3.6 M in Group A + C1 and 4.1 M in Group B + C2 (p = 0.035, HR:0.674 [0.468-0.972]), and 3.7 M in Group A + B and 3.7 M in Group C1 + C2 (p = 0.931, HR: 1.017 [0.643-1.412]), respectively. Grade 3 or 4 adverse events (Group A/B/C1/C2, %), were leukopenia (12/7/5/0), neutropenia (29/16/24/24), anemia (7/9/14/14), anorexia (10/2/14/10), nausea (7/2/10/5), diarrhea (5/0/10/0), and fatigue (5/2/10/5). Conclusions: The difference in OS between CPT-11 and PTX, and the efficacy of S-1 sequential therapy were not observed in second-line chemotherapy for AGC refractory to S-1 or SP. Disclosure: All authors have declared no conflicts of interest.