On June 11, 2012, U.S. Food and Drug Administration (FDA) has approved PerjetaTM (pertuzumab). Perjeta is approved in combination with Herceptin® (trastuzumab) and docetaxel chemotherapy for the treatment of people with HER2-positive metastatic breast cancer (mBC) who have not received prior anti-HER2 therapy or chemotherapy for metastatic disease. This approval is based on data from a Phase III study which showed that people with previously untreated HER2-positive metastatic breast cancer who received the combination of Perjeta, Herceptin and docetaxel chemotherapy lived a median of 6.1 months longer without their cancer getting worse (progression-free survival, or PFS) compared to Herceptin plus docetaxel chemotherapy (median PFS 18.5 vs. 12.4 months).
This is an exciting development. It must be kept in mind that the study was first line. It is not known how this regimen would work in patients who already failed Herceptin and other agents in the past and it would be premature to view it as a powerful salvage regimen. Baselga et al (2010) did find that the combination of pertuzumab and trastuzumab is active and well tolerated in patients with metastatic HER2-positive breast cancer who had experienced progression during prior trastuzumab therapy. However, how it compares to other available and active therapies is not known.
Intravenous pertuzumab is currently being evaluated in patients with breast cancer in the following trials: MARIANNE (advanced breast cancer), NEOSPHERE (early breast cancer), TRYPHAENA (HER2-positive stage II/III breats cancer) and APHINITY (HER2-positive nonmetastatic breast cancer). It might turn out to be powerful drug for previously Herceptin treated patients but this remains to be proven.
In September 2013, the FDA approved Perjeta for neoadjuvant use, based on very good results. Read the Professional version here.