Editor’s cAornEr Editor’s cornEr

The parental trastuzumab was first approved in 1998 and anti-HER2 pertuzumab (PERJETA™; Genentech/Roche) was first approved in 2012 as treatments for HER2-positive metastatic breast cancer. In the European Union, trastuzumab and per-tuzumab are approved, and trastuzumab emtansine is under-going regulatory review. Trastuzumab emtansine is approved for patients who were previously treated with trastuzumab and taxanes. It is currently also undergoing evaluation in the Phase 3 MARIANNE study (NCT01120184) of trastuzumab emtan-sine and pertuzumab vs. trastuzumab plus a taxane in patients with metastatic breast cancer; the Phase 3 TH3RESA study (NCT01419197) of trastuzumab emtansine compared with treat-ment of physician’s choice in patients with HER2-positive meta-static breast cancer who have received at least two prior regimens of HER2 directed therapy; and the Phase 3 KATHERINE stud