XELOX doublet regimen versus EOX triplet regimen as first-line treatment for advanced gastric cancer: An open-labeled, multicenter, randomized, prospective phase III trial (EXELOX)

Background: There is no consensus on whether triplet regimen is better than doublet regimen in the first-line treatment of advanced gastric cancer (AGC). We aimed to compare the efficacy and safety of oxaliplatin plus capecitabine (XELOX) and epirubicin, oxaliplatin, plus capecitabine (EOX) regimens in treating AGC.

Methods: This phase III trial enrolled previously untreated patients with AGC who were randomly assigned to receive the XELOX or EOX regimen. The primary endpoint was non-inferiority in progression-free survival (PFS) for XELOX as compared with EOX on an intention-to-treat basis.

Results: Between April 10, 2015 and August 20, 2020, 448 AGC patients were randomized to receive XELOX (n = 222) or EOX (n = 226). The median PFS (mPFS) was 5.0 months (95% confidence interval [CI] = 4.5-6.0 months) in the XELOX arm and 5.5 months (95% CI = 5.0-6.0 months) in the EOX arm (hazard ratio [HR] = 0.989, 95% CI = 0.812-1.203; P_{non-inferiority} = 0.003). There was no significant difference in median overall survival (mOS) (12.0 vs. 12.0 months, P = 0.384) or objective response rate (37.4% vs. 45.1%, P = 0.291) between the two groups. In patients with poorly differentiated adenocarcinoma and liver metastasis, the EOX arm had a significantly longer mOS (P = 0.021) and a trend of longer mPFS (P = 0.073) than the XELOX arm. The rate of grade 3/4 adverse events (AEs) was 42.2% (90/213) in the XELOX arm and 72.5% (156/215) in the EOX arm (P = 0.001). The global health-related quality of life (QoL) score was significantly higher in the XELOX arm than in the EOX arm during chemotherapy.

Conclusions: This non-inferiority trial demonstrated that the doublet regimen was as effective as the triplet regimen and had a better safety profile and QoL as a first-line treatment for AGC patients. However, the triplet regimen might have a survival advantage in patients with poorly differentiated adenocarcinoma and liver metastasis.