Phase I trial of afatinib and 3-weekly trastuzumab with optimal anti-diarrheal management in patients with HER2-positive metastatic cancer.

Background Trastuzumab is the mainstay of therapy for patients with HER2-positive breast and gastric cancer but resistance frequently occurs. Afatinib, an irreversible oral ErbB family blocker, shows clinical activity in trastuzumab-refractory HER2-positive metastatic breast cancer.