According to the European Medicines Agency, the best percentage change from baseline in the sum of the diameters of target lesions was −47.9% in the zolbetuximab group and −38.4% in the placebo group based on combined analyses of the GLOW and SPOTLIGHT studies.13) These findings suggest a promising antitumor effect of zolbetuximab as a molecularly targeted agent in patients with HER2-negative, CLDN-positive gastric cancer. This evidence concerns the gene ERBB2 and gastric cancer.