Patients with HER2– advanced-stage gastric or gastro-oesophageal junction (G/GEJ) cancers typically receive 5-fluorouracil, folinic acid and oxaliplatin (mFOLFOX6) or capecitabine and oxaliplatin (CAPOX), although survival with these regimens tends to be poor. Evidence suggests that CLDN18.2, a gastric-specific isoform of the tight-junction protein claudin 18 that is overexpressed in the majority of G/GEJ cancers, is a promising therapeutic target. Now, data from the phase III SPOTLIGHT trial show that addition of the anti-CLDN18.2 antibody zolbetuximab to mFOLFOX6 improves outcomes in this setting.