Is capecitabine better with lapatinib or trastuzumab for HER2 positive metastatic breast cancer?

This paper studied the effect of lapatinib (Tyverb) plus capecitabine (Xeloda) versus trastuzumab (Herceptin) plus capecitabine in patients with human epidermal growth factor receptor 2 (HER2) positive breast cancer that has spread to other parts of the body.

Trastuzumab is used  to treat HER2 positive breast cancer, and can improves outcomes for patients with HER2 positive breast cancer that is metastatic (has spread to other parts of the body). However, it is not effective for breast cancer that has spread to the brain. Thus, trastutuzumab is given together with capecitabine, a drug that is effective against breast cancer that has spread to the brain.  Studies have suggested that lapatinib has an effect on the brain, and so a combination of lapatinib and capecitabine may be even more beneficial. 

The authors evaluated whether trastuzumab and capecitabine or lapatinib and capecitabine was more effective in preventing breast cancer spread to the brain after treatment for metastatic breast cancer. 

Patients were randomly assigned to receive lapatinib plus capecitabine or trastuzumab plus capecitabine. At the start of this study, none of these patients had any cancer that had spread to the brain.

In 3% in patients receiving lapatinib and 5% in patients receiving trastuzumab the brain was the first place to which cancer returned following treatment. The average time for cancer to first return to the brain was 5.7 months in patients receiving lapatinib and 4.4 months in patients receiving trastuzumab.

The average progression free survival (period without disease worsening) was shorter for patients receiving lapatinib than for patients receiving trastuzumab. The average overall survival was 22.7 months for patients receiving lapatinib. The average overall survival was 27.3 months for patients receiving trastuzumab.

There was a greater occurrence of diarrhoea, nausea and rash in patients taking lapatinib than in patients taking trastuzumab. 11% of patients taking lapatinib and 13% of patients taking trastuzumab stopped treatment due to adverse events (undesired effect of treatment).

The authors concluded that treatment that includes trastuzumab  continues to be the standard of care in metastatic breast cancer. Lapatinib plus capecitabine treatment should be used only after disease worsens while taking trastuzumab.

The study was terminated early.