Trastuzumab Combined with Docetaxel-Based Regimens in Previously Treated Metastatic Gastric Cancer Patients with HER2 Over-Expression

Background/Aims: This study evaluates the efficacy and safety of trastuzumab combined with docetaxel-based chemotherapy in previously treated metastatic gastric carcinoma of Chinese patients with HER2 over-expression. Methodology: Twenty-two metastatic gastric cancer patients with HER2 over-expression (3+ by immunohistochemistry or HER2 amplification by fluorescence in situ hybridization) previously treated with 5-fluorouracil-based chemotherapy were eligible. Trastuzumab was administrated at 8mg/kg as a loading dose followed by 6mg/kg every 21 days. Docetaxel-based chemotherapy regimens were also given every 21 days. Results: Median age was 56 years. ECOG performance status was 0-2. Thirteen patients (59.1%) achieved partial response (PR) and 7 patients (31.8%) had stable disease (SD). Median progression free survival was 6.8 months and the median overall survival was 16.0 months. A patient with 3+ HER2 expression and HER2 gene amplification achieved PR after 6 cycles of combined treatment and received operation. Interestingly, his HER2 expression status in tumor tissue turned into negative after operation and he was still alive without progression until now. Trastuzumab combined with docetaxel-based chemotherapy was well tolerated. Grade 3-4 hematological toxicities were leucopenia (31.8%), neutropenia (18.2%) thrombocytopenia (9.1%) and anemia (4.5%). No unexpected toxicities, treatment-related deaths and symptomatic congestive heart failure were observed. Conclusions: Combinations of trastuzumab plus docetaxel-based regimens were well tolerated and effective in previously treated metastatic gastric cancer of Chinese patients with HER2 over-expression or gene amplification.