Recombinant humanized anti-PD-1 monoclonal antibody (JS001) as salvage treatment for advanced esophageal squamous cell carcinoma: Preliminary results of an open-label, multi-cohort, phase Ib/II clinical study.

116Background: Patients with Esophageal squamous cell carcinoma (EC) often present with advanced and metastatic stage disease, which has poor prognosis and limited treatment options, and represent an important unmet medical need especially in China/Asia. JS001, a humanized recombinant IgG4 antibody against PD-1, selectively blocks the interactions of PD-1 with its ligands PD-L1 and PD-L2, and promotes antigen specific T-cell activation. A phase I study of JS001 in Chinese patients with heavily pretreated solid tumors has demonstrated an acceptable safety profile in doses up to 10 mg/kg Q2W. Here we report the safety and efficacy of JS001 in a phase Ib/II clinical study in Chinese patients with refractory/metastatic EC. (Clinical trial ID: NCT02915432) Methods: Refractory/metastatic EC Patients receive JS001 3 mg/kg Q2W until disease progression or unacceptable toxicity. All patients with measurable disease will be assessed for clinical response every 8 weeks according to the RECIST 1.1 criteria. Tumor PD-...