Which combination of treatments is better for HER2 positive advanced breast cancer?

This study compared two treatment regimes for HER2 positive breast cancer; pyrotinib (Irene) plus vinorelbine (Navelbine), or lapatinib (Tykerb) plus capecitabine (Xeloda). It found that pyrotinib plus vinorelbine (PV) improved survival without cancer progressing compared to lapatinib plus capecitabine (LC). 

HER2-positive breast cancer tumors produce a protein called HER2. The HER2 protein enables the tumor to grow fast. HER2-positive tumors are often treated with a combination of treatments. One treatment is used to block the HER2 protein and stop the rapid growth of the tumor. Pyrotinib and lapatinib are such therapies.

The second treatment is a chemotherapy drug used to kill the tumor cells. Vinorelbine and capecitabine are commonly used chemotherapies. It is not clear which combination of treatments is most effective in patients with HER2-positive breast cancer that has progressed after previous anti-HER2 therapy.

224 patients with advanced breast cancer were involved in this study. All patients had previously received trastuzumab (Herceptin) anti-HER2 therapy and a taxane chemotherapy. 132 patients received lapatinib plus capecitabine (LC and 92 patients received pyrotinib plus vinorelbine (PV). Patients were followed up for an average of 20 months.

The average time before the tumor progressed was 8.3 months with PV and 5 months with LC. PV was associated with a 53% higher chance of surviving without cancer worsening compared to LC. PV was associated with a higher risk of severe diarrhea (23.9%) compared to LC (8.3%).

This study showed that a combination of pyrotinib plus vinorelbine was more effective in treating advanced HER2-positive breast cancer than a combination of lapatinib plus capecitabine. 

This study is based in China. More studies are needed to see if these findings apply to other ethnicities.