Background: Capecitabine plus cisplatin (XP) is a standard global regimen, while S-1 plus cisplatin (SP) is a Japanese standard for first-line treatment of advanced gastric cancer (AGC). We conducted a phase II trial comparing XP with SP for patients with AGC to confirm whether these regimens can be used as controls in a phase III study and to explore whether histological subtypes favour XP or SP.
Patients and methods: Eligible patients were randomised to receive either S-1 40 mg/m2 for 21 days plus cisplatin 60 mg/m2 (q5w) or capecitabine 1000 mg/m2 for 14 days plus cisplatin 80 mg/m2 (q3w). The primary end-point was progression-free survival (PFS). The secondary end-points were overall survival (OS), overall response rate (ORR) and safety.
Results: In 110 eligible patients, 24-week PFS was higher in both groups (SP 50.9%, XP 43.5%) than the protocol-specified threshold of 40%. The median PFS for SP versus XP was 5.6 and 5.1 months (hazard ratio [HR], 1.126; p = 0.5626); OS was 13.5 and 12.6 months (HR, 0.942; p = 0.7769) and the ORR was 42.4% and 69.4% (p = 0.0237), respectively. The most common grade ≥3 adverse events with SP/XP were anaemia (16%/20%), neutropenia (9%/18%) and anorexia (18%/13%). Subgroup analysis by histological classification showed no statistical difference between treatments.
Conclusions: XP and SP are comparable and can be recommended as control arms in a phase III study for AGC. Histological subtypes were not sensitive markers for the selection of XP or SP.
Clinical trial registration: NCT00140624.
Keywords: Advanced gastric cancer; Capecitabine plus cisplatin (XP); First-line chemotherapy; Histological subtypes; S-1 plus cisplatin (SP).
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