In patients with metastatic gastric cancer, median overall survival remains 
under 1 year and standard chemotherapy regimens are not able to substantially 
improve the prognosis of the patients. Amplification and over-expression of HER2 
is reported in approximately 20% of gastric tumours, challenging the use of 
targeted therapies. There are several targeted therapies in different stages of 
clinical development with trastuzumab being the first overcoming the regulatory 
hurdle and getting European Medicines Agency approval. In patients with advanced 
gastric or gastro-oesophageal junction cancer, addition of trastuzumab to 
chemotherapy significantly improved overall survival compared with chemotherapy 
alone. Addition of trastuzumab to chemotherapy did not increase the incidence of 
adverse events. Other agents targeting the HER2 pathway (lapatinib) or other 
domains of epidermal growth factor receptor family (cetuximab) are currently 
being investigated for the treatment of an advanced gastric cancer.