Promising efficacy of SHR-1210, a novel anti–programmed cell death 1 antibody, in patients with advanced gastric and gastroesophageal junction cancer in China

Background: The clinical response to anti–programmed cell death 1 (PD-1) antibodies in patients with advanced gastric and gastroesophageal junction (GEJ) cancer in China has not been reported. Methods: This study evaluated the efficacy and safety of SHR-1210, an anti–PD-1 antibody, in patients with advanced gastric/GEJ cancer in a phase 1 trial. The associations between candidate biomarkers (programmed death ligand 1 [PD-L1] expression, mismatch repair status, tumor mutation load, and lactate dehydrogenase [LDH] levels) and the efficacy of SHR-1210 were also explored. Results: Thirty patients with recurrent or metastatic gastric/GEJ adenocarcinoma who were refractory or intolerant to previous chemotherapy were enrolled between June 2, 2016, and June 8, 2017. Seven patients (23.3%) demonstrated objective responses, including 1 complete response. The objective response rates for patients with PD-L1–positive and PD-L1–negative tumors were 23.1% (3 of 13) and 26.7% (4 of 15), respectively (P = 1.000). Two treatment-related grade 3 or higher adverse events were reported: one was grade 3 pruritus, and the other (3.3%) was grade 5 interstitial lung disease. All 20 patients tested for the mismatch repair status had mismatch repair–proficient tumors, and the response rate was 30.0% (95% confidence interval, 11.9%-54.3%). Patients with a higher mutation load (4 of 10) tended to have better responses than those with fewer mutations (2 of 10), but the difference was not significant (P =.628). Patients with a >10% relative increase from the baseline LDH level were more likely to experience disease progression (90% [9 of 10]) than patients with a ≤10% change (40% [8 of 20]; P =.017). Conclusions: Anti–PD-1 antibody SHR-1210 shows encouraging efficacy in patients with advanced gastric/GEJ cancer in China, including mismatch repair–proficient subgroups.