Used with first-line chemotherapy in patients with unresectable locally advanced or metastatic gastric and gastroesophageal junction adenocarcinoma, sintilimab significantly improved overall survival compared with placebo, researchers report. “Our results showed a statistically significant benefit of sintilimab for the primary endpoints of overall survival at the interim efficacy analysis among patients with a [combined positive score (CPS)] of 5 or more and in all randomized patients irrespective of baseline CPS score,” conclude the authors. Sintilimab is an IgG4 monoclonal antibody that binds to programmed cell death 1 (PD-1).
The phase 3 clinical trial of 650 patients was conducted at 62 hospitals in China. Randomized to sintilimab or placebo combined with capecitabine and oxaliplatin (the XELOX regimen) every 3 weeks for a maximum of 6 cycles for up to 2 years, participants had these outcomes based on a primary endpoint of overall survival time from randomization: “Among the randomized patients, 397 (61.1%) had tumors with a PD-L1 CPS of 5 or more; 563 (86.6%) discontinued study treatment and 388 (59.7%) died; 1 patient (<0.1%) was lost to follow-up. Among all randomized patients, sintilimab improved overall survival compared with placebo (median, 15.2 vs 12.3 months; stratified hazard ratio [HR], 0.77 [95% CI, 0.63-0.94]; P = .009). Among patients with a CPS of 5 or more, sintilimab improved overall survival compared with placebo (median, 18.4 vs 12.9 months; HR, 0.66 [95% CI, 0.50-0.86]; P = .002). The most common grade 3 or higher treatment-related adverse events were decreased platelet count (sintilimab, 24.7% vs placebo, 21.3%), decreased neutrophil count (sintilimab, 20.1% vs placebo, 18.8%), and anemia (sintilimab, 12.5% vs placebo, 8.8%).”