Pertuzumab and trastuzumab infusion related cytokine release syndrome in a chemotherapy naive patient with metastatic breast cancer.

Pertuzumab is a monoclonal antibody that targets and down regulates HER-2/neu expression in ductal breast tumors. Other HER-2/neu monoclonal antibodies, particularly trastuzumab, have been implicated to induce infusion related reactions such as cytokine release syndrome (CRS). Here, we report a case of pertuzumab associated CRS prior to infusion of trastuzumab which warranted hospitalization for symptom management.