Real-world analysis of impact of trastuzumab on survival outcomes of HER2-positive biliary tract cancers

Biliary tract cancers (BTCs), particularly gallbladder carcinoma (GBC), are aggressive malignancies and exhibit significant geographical disparity, with a high incidence in Northern India. HER2 amplification represents a key targetable alteration in a subset of patients. A retrospective analysis at Tata Memorial Centre (Varanasi, India) evaluated real-world outcomes of trastuzumab in combination with chemotherapy for HER2-positive BTCs. A total of 91 patients with HER2-positive (immunohistochemistry 2+ amplified or 3+) BTCs were analyzed. The primary endpoints were progression-free survival (PFS) and overall survival (OS). The median age was 50 years. Nearly all patients had GBC (98.9%) and HER2 3+ positivity (91.2%); 76.9% had metastatic disease. Forty-nine patients (53.8%) received trastuzumab, mostly in the first line (38.5%). Both PFS and OS were significantly longer in the patients receiving trastuzumab. The median PFS was 11.8 months (95% CI 7.7-15.8) with trastuzumab versus 2.8 months (2.4-3.1) without; the median OS was 17.3 months (13.5-21.1) versus 5.8 months (4.3-7.3). The 2-year OS rate was 32.7% versus 11.8%. The authors conclude that in the real-world cohort from a high-incidence region, trastuzumab-based therapy was associated with a significant and clinically meaningful improvement is survival outcomes for HER2-positive BTCs.