Immunotherapy and Targeted Therapy for Advanced Gastroesophageal Cancer: ASCO Guideline Update

The target population for these recommendations is patients with unresectable locally advanced, advanced, or metastatic gastroesophageal cancer. Results from testing for actionable biomarkers should be available as soon as possible to inform treatment decision making. Immunotherapy with doublet chemotherapy is recommended for patients with proficient mismatch repair (pMMR)/microsatellite stable (MSS) human epidermal growth factor receptor 2 (HER2)-negative gastroesophageal adenocarcinoma or squamous cell carcinoma and PD-L1 expression ≥1; patients with higher PD-L1 expression are more likely to benefit from immunotherapy. Zolbetuximab is recommended for patients with gastroesophageal adenocarcinoma, PD-L1 <1, and positive CLDN18.2 expression. Patients with dual PD-L1 and CLDN18.2 positivity should engage in shared decision making, considering the factors outlined in the guideline. Doublet chemotherapy alone is recommended for patients who are not positive for actionable biomarkers or are not considered candidates for targeted therapy or immunotherapy. For patients with pMMR/MSS HER2-positive gastric/gastroesophageal junction (GEJ) adenocarcinoma, trastuzumab and doublet chemotherapy is recommended; for patients with PD-L1 expression ≥1, the addition of pembrolizumab is recommended. Immunotherapy alone or with doublet chemotherapy is recommended for patients with mismatch repair deficient/microsatellite instability-high gastroesophageal cancer. Second-line therapy options include ramucirumab with paclitaxel, trastuzumab deruxtecan for HER2-positive gastric/GEJ adenocarcinoma, and immunotherapy for PD-L1 ≥1 esophageal squamous cell carcinoma after first-line combination chemotherapy without immunotherapy.Additional information is available at www.asco.org/gastrointestinal-cancer-guidelines.