Real-World Association of HER2/ <i>ERBB2</i> Concordance with Trastuzumab Clinical Benefit in Advanced Esophagogastric Cancer
Stacey Stein, Jeremy Snider, Siraj M. Ali, Rebecca A. Miksad, Brian M. Alexander, Emily Castellanos, Alexa B. Schrock, Russell W. Madison, Akshay Swaminathan, Jeffrey M. Venstrom, Margaret McCusker
Abstract
Aim: To assess concordance between HER2 status measured by traditional methods and ERBB2 amplification measured by next-generation sequencing and its association with first-line trastuzumab clinical benefit in patients with advanced esophagogastric cancer. Methods: Retrospective analysis of HER2/ERBB2 concordance using a deidentified USA-based clinicogenomic database. Clinical outcomes were assessed for patients with HER2+ advanced esophagogastric cancer who received first-line trastuzumab. Results: Overall HER2/ERBB2 concordance was 87.5%. Among patients who received first-line trastuzumab, concordant HER2/ERBB2 was associated with longer time to treatment discontinuation (adjusted hazard ratio [aHR]: 0.63; 95% CI: 0.43–0.90) and overall survival (aHR: 0.51; 95% CI: 0.33–0.79). ERBB2 copy number ≥25 (median) was associated with longer time to treatment discontinuation (aHR: 0.56; 95% CI: 0.35–0.88) and overall survival (aHR: 0.52; 95% CI: 0.30–0.91). Conclusion: HER2/ERBB2 concordance and higher ERBB2 copy number predicted clinical benefit from trastuzumab.