Sahin U, et al. - Whether or not IMAB362 is a potent, targeted immunotherapeutic agent was investigated via this first in-human phase I study with adult patients (N=15) with advanced gastric or gastro-esophageal junction cancer split into five sequential single dose–escalation cohorts (33, 100, 300, 600, and 1000 mg/m²) following a 3 + 3 design. In gastric or gastro-esophageal junction cancers, CLDN18.2 is a tumor-specific marker. Findings revealed a mediating effect of IMAB362 (an anti-CLDN18.2 mAb) in tumor cell death through ADCC and CDC. Generally good tolerability was observed for a single-dose of IMAB362 at doses of 33–1000 mg/m². They determined IMAB362 (300–600 mg/m²) was suitable for further evaluation.