Safety, Activity, and Biomarkers of SHR-1210, an Anti-PD-1 Antibody, for Patients with Advanced Esophageal Carcinoma

Purpose: The current management of advanced esophageal squamous cell carcinoma (ESCC) remains unsatisfactory. We investigated the safety, efficacy, and biomarkers of SHR-1210, an anti-PD-1 antibody, in patients with recurrent or metastatic ESCC. Experimental Design: This study was part of a phase I trial in China. Patients with advanced ESCC who were refractory or intolerant to previous chemotherapy were enrolled. Eligible patients received intravenous SHR-1210 at a dose of 60 mg, with escalation to 200 and 400 mg (4-week interval after first dose followed by a 2-week schedule) until disease progression or intolerable toxicity. The associations between candidate biomarkers (PD-L1 and somatic mutation load) and the efficacy of SHR-1210 were also explored. Results: Between May 11, 2016, and December 9, 2016, a total of 30 patients from one site in China were enrolled. Ten patients (33.3%) had an independently assessed objective response. Median progression-free survival was 3.6 months (95% CI, 0–7.2). Three (10.0%) treatment-related grade 3 adverse events were reported: two (6.7%) pneumonitis and one (3.3%) increased cardiac troponin I. No grade 4 or grade 5 treatment-related adverse events were reported. The exome sequencing and analysis showed that the mutational burden and the potential mutation-associated neoantigen count were associated with better responses. An objective response was more common in patients with PD-L1–positive tumors as defined by ≥5% staining (7 of 15 patients) than in those with PD-L1–negative tumors (1 of 9 patients). Conclusions: In this population of ESCC patients, SHR-1210 had a manageable safety profile and promising antitumor activity. Clin Cancer Res; 24(6); 1296–304. ©2018 AACR.