Serum HER2 extracellular domain as a predictive biomarker for trastuzumab deruxtecan treatment response in HER2-positive gastric cancer: a real-world study

Yukiya Narita, Ryosuke Kumanishi, Koshi Takahashi, Toshiki Masuishi, Hiroya Taniguchi, Shigenori Kadowaki, Kazunori Honda, Masashi Ando, Tadahisa Fukui, Masahiro Tajika, Kei Muro

Therapeutic Advances in Gastroenterology

Published online on January 11, 2026

Abstract

Therapeutic Advances in Gastroenterology, Volume 19, January-December 2026.
Background:No established predictive biomarker beyond tissue HER2 status currently exists for trastuzumab deruxtecan (T-DXd) treatment response in human epidermal growth factor receptor 2 (HER2)-positive advanced gastric cancer (AGC). Serum HER2 ...