Comparison of S-1-cisplatin every 5 weeks with capecitabine-cisplatin every 3 weeks for HER2-negative gastric cancer (recurrent after S-1 adjuvant therapy or chemotherapy-naïve advanced): pooled analysis of HERBIS-2 (OGSG 1103) and HERBIS-4A (OGSG 1105) trials.

BACKGROUND: We previously reported the HERBIS-4A phase II trial comparing S-1 plus cisplatin (SP) with capecitabine plus cisplatin (XP) in chemotherapy-naïve patients with HER2-negative advanced gastric cancer (GC). We performed a pooled analysis of HERBIS-4A and HERBIS-2, the phase II trial comparing SP with XP in HER2-negative recurrent GC patients with a recurrence-free interval after S-1 adjuvant therapy of ≥ 6 months. PATIENTS AND METHODS: Patients were randomly assigned to receive either SP [S-1 (40-60 mg twice daily for 21 days) plus cisplatin (60 mg/m2 on day 8), every 5 weeks] or XP [capecitabine (1000 mg/m2 twice daily for 14 days) plus cisplatin (80 mg/m2 on day 1), every 3 weeks]. RESULTS: In the pooled analysis, SP (n = 44-50) showed a longer progression-free survival [6.4 versus 5.1 months; hazard ratio (HR), 0.666; P = 0.062], overall survival (14.8 versus 10.6 months; HR, 0.695; P = 0.099), and time to treatment failure (4.6 versus 3.6 months; HR, 0.668; P = 0.045) as well as a higher disease control rate (86.4% versus 68.1%, P = 0.149) compared with XP (n = 47-51). A significant survival advantage for SP over XP was apparent in patients with a performance status of 0, a differentiated-type tumor histology, or a primary tumor localization to the upper portion of the stomach. CONCLUSION: Our pooled analysis supports the use of SP in the first-line setting for patients with HER2-negative advanced or recurrent GC with a recurrence-free interval of ≥ 6 months. CLINICAL TRIAL REGISTRATION: The HERBIS-2 trial was registered with UMIN-CTR as UMIN000006105.