A phase Ib/II open label study of IMU-131 HER2/Neu peptide vaccine plus cisplatin and either 5-fluorouracil or capecitabine chemotherapy in patients with HER2/Neu overexpressing metastatic or advanced adenocarcinoma of the stomach or gastroesophageal junction.

TPS176Background: Gastric cancer is the 5th most frequently diagnosed cancer and the 3rd leading cause of cancer deaths. HER2/neu is overexpressed in 15% to 25% of patients with gastric cancer and associated with a poor prognosis. Monoclonal antibodies against HER2/neu have been shown to be effective but alternative treatments are needed due to cost and global availability issues. IMU-131 is a B-cell peptide vaccine composed of 3 B cell epitopes derived from the extracellular domain of HER2/neu. Polyclonal antibodies against IMU-131 peptides binding 3 separate regions (DIII, IV) of HER2/neu have been shown to elicit antitumor activity in vitro and a phase I study demonstrated safety and immunogenicity in Her-2 +/++ metastatic breast cancer patients. Fusion of the single peptides into a hybrid peptide conjugated to CRM197 in conjunction with the adjuvant Montanide (P467-CRM-Montanide) improved formulation and stability of the vaccine. With the present Phase 1b/2 trial performed in patients with HER2/neu ov...