Targeting PD-L1 in Gastric Cancer

Immune checkpoint inhibitors targeting programmed death protein 1 (PD-1; including nivolumab, pembrolizumab, and tislelizumab) are combined with first-line chemotherapy in advanced gastric cancer, but the survival benefit is limited to patients testing positive for anti–programmed death-ligand 1 (PD-L1).

Investigators in China report results of the industry-sponsored, randomized, placebo-controlled GEMSTONE-303 trial evaluating the addition of the anti–PD-L1 agent sugemalimab to first line chemotherapy in patients with advanced gastric cancer and a PD-L1 combined positive score (CPS) >5%. Of the 479 patients treated with capecitabine/oxaliplatin combined with either sugemalimab or placebo, 90% had prior gastrectomy, 39% had hepatic metastases, 46% had CPS scores 5–9%, and 54% had scores >10%.

The coprimary endpoint of overall survival was improved for sugemalimab over placebo (median, 15.6 vs. 12.6 months; hazard ratio, 0.75), as was the coprimary endpoint of progression-free survival (7.6 vs. 6.1 months; HR, 0.66). Response rates were higher with sugemalimab compared with placebo (69% vs. 53%). No new safety signals were observed. Rates of grade 3–5 serious treatment-related adverse events were similar in the sugemalimab and placebo groups (54% and 51%).