Statistical Considerations A. Study statistics This is a phase I study designed to evaluate (1) the toxicity of a HER2 HLA -A2 specific peptide -based vaccine administered concomitantly with trastuzumab and (2) the immunogenicity of HER2 HLA -A2 specific peptide - based vaccine administered concomitantly with trastuzumab. The first objective will be a chieved by assessing baseline, the type and grade of toxicities and any adverse events noted by the investigator.