Combining targeted therapies: the benefits of directly targeting HER2+ breast cancer

The authors aimed to determine the effectiveness of targeted treatments and also compared combination therapies.

HER2 positive breast cancer is associated with the over-expression (production) of the human epidermal growth factor receptor 2 (HER2+). HER2+ breast cancer is known to be more aggressive with a poorer prognosis (outlook). Currently, trastuzumab (Herceptin), pertuzumab (Perjeta) and lapatinib (Tyverb) are approved as standard treatment for this form of cancer. These treatments block the activity of HER2.

Studies have now begun to suggest, however, that using a combination of these targeted therapies would result in increased survival and prognosis.

The aims of this study were to fully compare the effectiveness and safety of combination therapies that target HER2+ expression of breast cancer.

This study reviewed 25 articles that included the treatment of 11,276 women with HER2+ breast cancer over a course of 31 months.

Six different HER2-targeted treatments were compared. These included trastuzumab emtansine (Kadcyla), lapatinib, trastuzumab, pertuzumab, alone or in combination. Patients received targeted treatments along with chemotherapy treatments.

Overall, trastuzumab emtansine combination therapy proved to be the most efficient treatment in terms of survival (40% reduced risk of death compared to those treated with lapatinib only). A combination of pertuzumab and trastuzumab was 1.85 times more likely to lead to a respose (such as tumor shrinkage) than trastuzumab alone, and 3 times more likely than pertuzumab alone.

Reduced side effects, such as rash and diarrhea, were also observed in those who received the pertuzumab and trastuzumab combination compared to other treatments.

The authors concluded that combinations of HER2 targeted treatments were safe and more effective than single treatments. 

This was an analysis of multiple studies, and some patient groups were larger than others.