Phase II of trastuzumab and cisplatin in patients (pts) with advanced gastric cancer (AGC) with HER2/neu overexpression/amplification

4613 Background: Trastuzumab(T) exhibits activity in human gastric cancer cells that overexpress HER2/neu. We previously reported a 13.5% HER2/neu overexpression/amplification in AGC or gastroesofageal junction (GEJ) cancers (Gravalos C, et al. J Clin Oncol 24, 18S, 200s, abstr # 4089). We designed a phase II trial to determine the efficacy and tolerability of T and cisplatin(C) in pts with ACG with HER2/neu overexpression/amplification. Exploratory objectives include analysis of c-erbB-2 extracellular domain and correlation of the results with histological erB-2/neu overexpression and with clinical response Methods: Chemo-naive pts with adenocarcinoma histopatologically confirmed, HER2/neu overexpression/amplification, measurable, no operable, locally advanced or metastatic AGC, age ≥ 18, ECOG ≤ 2, FEVI ≥ 50% and adequate organ function were eligible. Prior adjuvant radiotherapy or/and chemotherapy were allowed. Immunohistochemistry (IHC) was performed using herceptest. A fluorescence in situ hybridizati...