January 21, 2015 Emma Shtivelman, PhD
Pertuzumab (Perjeta) is a relatively new drug that targets HER2, a protein found at higher-than-normal levels in about 15% to 20% of all breast cancers. Too much HER2 leads to tumor growth. Currently, all newly diagnosed breast cancer patients have their tumors’ HER2 levels tested. Knowing whether a patient’s HER2 levels are abnormally high (HER2-positive) or normal (HER2-negative) is a major factor in choosing a treatment, thanks to the availability of trastuzumab (Herceptin) and, now, other HER2-targeted drugs such as Perjeta, T-DM1 (Kadcyla), and lapatinib (Tykerb). These drugs are all used to treat HER2-positive patients.