ERBB2 and breast cancer: In a Phase I trial of patients with advanced or metastatic HER2-positive BC pretreated with anti-HER2 drugs, MEDI4276 resulted in 1/47 complete response (0.5 mg/kg) and 2/47 partial responses (0.6 and 0.75 mg/kg) but intolerable toxicity primarily on increased liver function tests [55].