Perjeta is a medicine that targets the HER2 receptor, a protein found on the outside of many normal cells and in high quantities on the outside of cancer cells in HER2-positive cancers. Perjeta is designed specifically to prevent the HER2 receptor from pairing (or ‘dimerising’) with other HER receptors (EGFR/HER1, HER3 and HER4) on the surface of cells, a process that is believed to play a role in tumour growth and survival. Binding of Perjeta to HER2 may also signal the body’s immune system to destroy the cancer cells. The mechanisms of action of Perjeta and Herceptin (trastuzumab) are believed to complement each other, as both bind to the HER2 receptor, but to different locations. The combination of Perjeta and Herceptin is thought to provide a more comprehensive, dual blockade of HER signalling pathways, thus preventing tumour cell growth and survival.
In the US, Europe and other countries, Perjeta is approved in combination with Herceptin and chemotherapy for the neoadjuvant (pre-surgery) treatment of people with HER2-positive, locally advanced, inflammatory, or early stage breast cancer, and as a first-line treatment for advanced HER2-positive breast cancer. Perjeta is also approved in over 80 countries, including the EU and US, in combination with Herceptin and chemotherapy (the Perjeta-based regimen) for the adjuvant (post-surgery) treatment of people with HER2-positive early breast cancer at high risk of recurrence.