Are two HER-2 medications combined with hormone therapy effective?

This trial aimed to evaluate the use of a second treatment targeting HER-2 in a group of patients that had HER-2, HR positive metastatic breast cancer. This study found that patients treated with dual HER-2 medications with hormone therapy had a superior progression free survival as compared to those using one medication targeting HER-2. 

Breast cancer is classified into different subtypes depending on the presence or absence of certain receptors (proteins found on the surface of the cancer cells). These subtypes influence treatment options, and also directly affect disease prognosis. Hormone receptor (HR) positive cancer grows in response to female hormones such as estrogen. Another protein that influences breast tumor growth is HER-2.

Hormones and HER-2 can be targeted by medical treatment. Trastuzumab (Herceptin; TRAS) and apatinib (Tykerb; LAP) are medications that target HER-2. Treatments such as aromatase inhibitors (AI) target hormones such as estrogen.

It is known that HER-2 and HR targeting treatments used together are a good option for HER-2, HR positive metastatic breast cancers. It is unclear if an additional treatment that targets HER-2 would be of benefit. 

This trial aimed to evaluate the use of a second treatment targeting HER-2 in a group of patients who had HER-2, HR positive metastatic breast cancer. This trial included 355 patients. 120 received LAP + TRAS and AI, 117 received TRAS and AI, and 118 received LAP and AI. 

Progression free survival (time from treatment until disease progression) was 11 months for those who received LAP + TRAS and AI compared to 5.7 months for TRAS and AI. Overall response and overall survival was superior for LAP + TRAS + AI. Common side effects were diarrhea, skin rashes, nausea and nail changes. These were more common in the LAP + TRAS + AI group. 

This study found that patients treated with LAP + TRAS + AI had a superior progression free survival as compared to TRAS and AI in patients who had HER2-positive/HR-positive metastatic breast cancer.