US approval for anti-HER2 therapy Perjeta (pertuzumab) against breast cancer

The US Food and Drug Administration (FDA) has approved the use of anti-HER2 therapy Perjeta (pertuzumab) to treat patients with previously untreated HER2-positive metastatic breast cancer.

The protein human epidermal growth factor receptor 2 (HER2) is involved in normal cell growth, but it is overproduced by some cancer cells (known as HER2-positive). This overproduction plays a key part of the growth of these cancerous cells, and hence the development of the disease. Perjeta – marketed by Genentech, a member of the Roche group – is a monoclonal antibody that targets the HER2 protein.

Metastatic breast cancer is where the cancerous cells have spread to other sites in the body. HER2 positive breast cancer account for 15-20% of breast cancers, and is a particularly aggressive form of the disease.

Perjeta has been approved for use alongside Herceptin (trastuzumab) – another anti-HER2 therapy – and the chemotherapeutic docetaxel. Herceptin and Perjeta are believed to target different regions the HER2 protein, meaning they are more effective when used together.

The approval came after a Phase III clinical trial demonstrated that this three-pronged approach gave patients a median of over 6 months longer (18.5 months compared with 12.4) without their cancer progressing compared to using just Herceptin and docetaxel together.