ERBB2 and Decreased total monocyte count: Early phase trials of the bispecific antibodies MDX-447 (humanized Fab’2 anti-FcγRI x humanized Fab’2 anti- EGFR), MDX-H210 (humanized Fab’2 anti-FcγRI x Fab’2 anti-HER2/neu) and MDX-33, an anti-FcγRI mAb, to treat several types of solid malignancies, resulted in monocytopenia and elevated serum cytokine levels.