Lapatinib plus trastuzumab for a patient with heavily pre-treated gastric cancer that progressed after trastuzumab.

A 57-year-old female with advanced gastric cancer was referred to our hospital. She underwent neoadjuvant chemotherapy with S-1 plus cisplatin followed by curative gastrectomy. Weekly paclitaxel and combination chemotherapy with irinotecan plus cisplatin were administered for lymph node recurrence, but the tumor progressed. Since the human epidermal growth factor receptor 2 status of her gastric cancer specimen was strongly positive, docetaxel plus trastuzumab was administered for three cycles. However, the lymph node metastasis appeared to enlarge and abdominal pain worsened. Therefore, combination chemotherapy with lapatinib and weekly trastuzumab was initiated. A computed tomographic scan after 3 months of treatment showed stable disease. Although dose reduction of lapatinib was necessary due to Grade 3 diarrhea, the patient has continued this treatment on an outpatient basis without signs of disease progression for 8 months after initiation. In this case, trastuzumab plus lapatinib resulted in durable stable disease, despite the appearance of progression during prior chemotherapy with trastuzumab.