The FDA has accepted Roche’s Biologics License Application for pertuzumab (Omnitarg) and granted Priority Review. The proposed indication is pertuzumab in combination with trastuzumab (Herceptin) and docetaxel chemotherapy for people with HER2-positive metastatic or locally recurrent, unresectable breast cancer, who have not received previous treatment or whose disease has relapsed after adjuvant therapy. The FDA confirmed the action date is June 8, 2012.
The pertuzumab application is based on results from the pivotal phase III CLEOPATRA study. The study demonstrated a 6.1-month improvement in median progression-free survival for people who received a pertuzumab-based regimen (pertuzumab combined with trastuzumab and docetaxel) compared to those who received trastuzumab and chemotherapy alone (median progression-free survival = 18.5 vs 12.4 months).
Underlying Mechanisms
Pertuzumab, a humanized monoclonal antibody, is unique in that it is designed specifically to prevent the HER2 receptor from pairing with other HER receptors, a process that is believed to play a critical role in the growth and formation of several different cancer types. By preventing receptor pairing, pertuzumab is thought to block cell signalling, which may inhibit cancer cell growth or lead to the death of the cancer cell. Binding of pertuzumab to HER2 may also signal the body’s immune system to destroy the cancer cells.
The mechanisms of action of pertuzumab and trastuzumab are believed to complement each other, as both bind to the HER2 receptor but on different regions. ■
