The US Food and Drug Administration (FDA) approved pertuzumab (Perjeta; Genentech) for intravenous use in patients with HER2-positive metastatic breast cancer. Pertuzumab, a humanized monoclonal antibody, is approved for use in combination with the other anti-HER2 trastuzumab (Herceptin) and docetaxel (Taxotere) chemotherapy in patients with metastatic breast cancer who have not been treated previously with an anti-HER2 therapy or with chemotherapy. The approval was done under the expedited review process.
In a clinical trial designed to evaluate the safety and efficacy of pertuzumab, 808 patients with HER2-positive metastatic breast cancer were randomized to trastuzumab plus docetaxel combined with either pertuzumab or with placebo. The median progression-free survival was 18.5 months in patients receiving the pertuzumab combination compared with 12.4 months with the placebo combination.
The most common side effects in the pertuzumab combination group were diarrhea, hair loss, a decrease in white blood cells, nausea, fatigue, rash, and peripheral neuropathy.
Pertuzumab works by targeting a different part of the HER2 protein than trastuzumab, which may explain the added benefits when these 2 anti-HER2 drugs are administered together.
Pertuzumab was approved with a boxed warning regarding the potential risk of death or severe effects in a fetus. Pregnancy status must be verified before the start of pertuzumab treatment.
In addition, because of production issues that could affect the long-term supply of pertuzumab, the FDA approval was limited to drug product that has not been affected by those issues.
“Given the need for additional treatments for metastatic breast cancer, we made the decision to approve this drug today and not to delay its availability to patients pending resolution of the production issues relating to future supply,” said Janet Woodcock, MD, Director of FDA’s Center for Drug Evaluation and Research. “Genentech is currently developing a plan to mitigate the effect on patients of any potential shortage of Perjeta.” (June 8, 2012)
