A real-world analysis from Northern India found that trastuzumab-based therapy was associated with improved survival outcomes in patients with HER2-positive biliary tract cancers, a population largely represented by gallbladder carcinoma.
The study, REAL TAB, was published in JCO Oncology Advances on June 2, 2026.
Original article title: Impact of Trastuzumab on Survival Outcomes in Human Epidermal Growth Factor Receptor 2–Positive Biliary Tract Cancers: A Real-World Analysis From a High-Incidence Region (REAL TAB)
Authors: Anuj Gupta, Bal Krishna Mishra, Bipinesh Sansar, Ayushi Pragya, Ravindra Kumar, Arpita Singh, Ankita Pal, Arvind Upadhyay, Zachariah Chowdhury, Ipsita Dhal, Himani Rai, Neha Singh, Shreya Shukla, Lincoln Pujari, Somnath Dey, Mayank Tripathi, and Akhil Kapoor.
Background
Biliary tract cancers are aggressive malignancies that are often diagnosed at an advanced stage. Gallbladder carcinoma is particularly common in Northern India, where it represents a major clinical burden.
HER2 amplification or overexpression is a targetable alteration in a subset of biliary tract cancers, especially gallbladder carcinoma and extrahepatic cholangiocarcinoma. REAL TAB evaluated whether adding trastuzumab to chemotherapy was associated with improved outcomes in patients with HER2-positive biliary tract cancers treated in routine clinical practice.
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Study Design
REAL TAB was a retrospective, single-institution study conducted at a tertiary cancer center in North India.
The analysis included 91 patients with HER2-positive biliary tract cancers treated between January 2019 and August 2025. HER2 positivity was defined as immunohistochemistry 3+ or immunohistochemistry 2+ with confirmed amplification.
The primary endpoints were progression-free survival and overall survival. Among the included patients, the median age was 50 years, and 70.3% were women. Nearly all patients had gallbladder carcinoma, and 76.9% had metastatic disease. Most tumors were HER2 3+ positive.
Trastuzumab was administered with chemotherapy to 49 patients, while 42 patients received chemotherapy without trastuzumab. Trastuzumab was most commonly used in the first-line setting.
Key Results
In the overall cohort, median progression-free survival was 5.4 months, and median overall survival was 10.6 months. Patients who received trastuzumab had longer survival outcomes compared with those who did not receive trastuzumab. Median progression-free survival was 11.8 months with trastuzumab versus 2.8 months without trastuzumab. Median overall survival was 17.3 months with trastuzumab versus 5.8 months without trastuzumab.
The 2-year progression-free survival rate was 27.5% in the trastuzumab group, while no patients in the non-trastuzumab group reached 2-year progression-free survival. The 2-year overall survival rate was 32.7% in the trastuzumab group compared with 11.8% in the non-trastuzumab group.
In multivariable analysis, trastuzumab remained independently associated with improved overall survival (HR, 0.48; 95% CI, 0.29 to 0.80) and progression-free survival (HR, 0.24; 95% CI, 0.14 to 0.41). Sensitivity analyses, including metastatic-only patients and first-line trastuzumab use, showed concordant results.
Safety
Safety reporting was limited by the retrospective design. Among patients who received trastuzumab-based therapy, the most common grade 1 or 2 adverse events included nausea, anemia, fatigue, neutropenia, and peripheral sensory neuropathy.
Grade 3 or higher toxicities were reported in approximately 16% of patients in the trastuzumab group, mainly neutropenia and thrombocytopenia. No symptomatic trastuzumab-induced cardiotoxicity was reported.
Overall, the safety profile was consistent with gemcitabine- and platinum-based chemotherapy, and the addition of trastuzumab did not appear to substantially increase toxicity in this real-world cohort.
Limitations
The study was retrospective and nonrandomized, which introduces potential selection bias. Patients in the trastuzumab group had a lower disease burden than those in the non-trastuzumab group, which may have influenced outcomes. The sample size was modest, and residual confounding cannot be excluded despite adjusted and sensitivity analyses. Therefore, the findings should be interpreted as associative rather than definitively causal.
Takeaway
REAL TAB adds real-world evidence for trastuzumab-based therapy in HER2-positive biliary tract cancers, a cohort composed predominantly of gallbladder carcinoma from a high-incidence region. Patients who received trastuzumab with chemotherapy had longer progression-free and overall survival than those treated without trastuzumab. The findings also reinforce the value of routine HER2 testing in advanced biliary tract cancers, especially where gallbladder cancer is common.
The full article is available in the JCO Oncology Advances.
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