The phase 2 ILUSTRO study investigated the combination of three drugs – zolbetuximab (an antibody against CLDN18.2), mFOLFOX6 chemotherapy and nivolumab (a PD-1 inhibitor) – as first-line treatment for patients with unresectable or metastatic adenocarcinoma of the stomach or gastroesophageal junction who were CLDN18.2 positive and HER2 negative[1][3]. In cohort 4B of 71 patients, median progression-free survival (PFS) was 14.8 months, with patients with high CLDN18.2 expression and a PD-L1 score of at least 1 extending to 23.6 months[2]. This efficacy was significantly better than historical data, where median PFS with first-line immunotherapy and chemotherapy was 7.5–8 months[3]. The treatment was safe, although 98.7% of patients experienced drug-related adverse effects, most commonly nausea (80.5%) and decreased appetite (72.7%)[2]. The results are promising and support further testing of this combination in phase 3 studies[1].