Differences in efficacy of biweekly irinotecan plus cisplatin versus irinotecan alone in second-line treatment of advanced gastric cancer with or without prior gastrectomy.

Abstract

Background: Biweekly irinotecan plus cisplatin combination therapy (BIRIP) and irinotecan monotherapy (IRI) are both expectable second-line chemotherapy (SLC) options for treating advanced gastric cancer (AGC). Although many patients receiving SLC have undergone gastrectomy, the impact of gastrectomy on SLC remains unclear, and the impact of gastrectomy may vary from regimen to regimen.

Patients and methods: A total of 290 eligible patients registered in two randomized phase III trials evaluating BIRIP (IRI, 60 mg/m²; CDDP, 30 mg/m², q2w) or IRI (150 mg/m², q2w) for patients with AGC was classified into the prior gastrectomy subgroup (PGG) or the no gastrectomy subgroup (NGG). We performed a subgroup analysis to evaluate the impact of gastrectomy on second-line BIRIP and IRI.

Results: The BIRIP demonstrated significantly longer OS (11.1 vs. 6.8 months; HR 0.64; P = 0.026) and PFS (3.7 vs. 2.3 months; HR 0.54; P = 0.003) than the IRI, as well as better ORR (23.5% vs. 7.1%, P = 0.046) and DCR (74.5% vs. 47.6%, P = 0.010) in NGG. Although in PGG, the BIRIP failed to demonstrate differences in OS (13.8 vs. 13.8 months; HR 0.94; P = 0.722), PFS (4.9 vs. 4.5 months; HR 0.82; P = 0.194), ORR (18.3% vs. 20.5%) and DCR (70.4% vs. 65.1%). The incidence of grade 3 or worse adverse events did not differ except for a high incidence of anemia in the BIRIP group in PGG.

Conclusions: BIRIP was an effective treatment option that may improve survival outcomes among patients with AGC without previous gastrectomy.

Clinical trial registration: UMIN000025367.