DISCLAIMER

The contents of the presentations above are designed for educational and scientific exchange purposes and are not promotional. They may contain information on investigational products or investigational uses of approved products. No conclusions regarding safety and/or efficacy for such investigational products or uses may be made.
 

SUMMARY

This analysis from the HERIZON‑GEA‑01 trial characterized gastrointestinal adverse events, with a focus on diarrhea, in patients with previously untreated HER2‑positive metastatic gastroesophageal adenocarcinoma treated with zanidatamab‑containing regimens or trastuzumab plus chemotherapy. Patients were randomized 1:1:1 to the investigational combination of zanidatamab plus tislelizumab plus chemotherapy, zanidatamab plus chemotherapy, or trastuzumab plus chemotherapy. Median treatment duration was 43.1 weeks, 31.0 weeks, and 30.0 weeks, respectively. Diarrhea was the most frequently reported gastrointestinal adverse event across all treatment arms, with most first‑onset events occurring during cycle 1 and a median duration of less than 2.5 weeks. Few patients experienced first‑onset diarrhea after cycle 6. Discontinuations, dose reductions, or delays of HER2‑targeted therapy due to diarrhea were infrequent, and diarrhea was more commonly managed through chemotherapy dose modification. Immune‑mediated colitis was reported in 2.7% of patients receiving zanidatamab plus tislelizumab plus chemotherapy.