ERBB2 and breast cancer: Clinical trials of active-targeted nanocarriers, such as MM-302 (HER2-targeted liposomal doxorubicin), showed improved objective response rates (11% vs. 0% in controls) in phase II studies for advanced breast cancer, though PFS gains were modest (7.6 vs. 5.5 months) due to accelerated clearance in PEG-immunized patients [21].